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Journal articles on the topic 'Traditional borehole drilling'
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1
Talalay, Pavel, Zhengyi Hu, Huiwen Xu, Dahui Yu, Lili Han, Junjie Han, and Lili Wang. "Environmental considerations of low-temperature drilling fluids." Annals of Glaciology 55, no. 65 (2014): 31–40. http://dx.doi.org/10.3189/2014aog65a226.
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AbstractThe introduction of low-temperature fluid into boreholes drilled in ice sheets helps to remove drilling cuttings and to prevent borehole closure through visco-plastic deformation. Only special fluids, or mixtures of fluids, can satisfy the very strict criteria for deep drilling in cold ice. The effects of drilling fluid on the natural environment are analyzed from the following points of view: (1) occupational safety and health; (2) ozone depletion and global warming; (3) chemical pollution; and (4) biological pollution. Traditional low-temperature drilling fluids (kerosene-based fluids with density additives, ethanol and n-butyl acetate) cannot be qualified as intelligent choices from the safety, environmental and technological standpoints. This paper introduces a new type of low-temperature drilling fluid composed of synthetic ESTISOLTM esters, which are non-hazardous substances. ESTISOLTM 140 mixtures with ESTISOLTM 165 or ESTISOLTM F2887 have an acceptable density and viscosity at low temperature. To avoid the potential for biological contamination of the subglacial environment, the borehole drilling fluid should be treated carefully on the surface.
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Zhang, Jun, Chi Ai, Bo Zeng, Yuwei Li, and Jia Zeng. "Study on Wellbore Stability of Shallow Sediments in Deepwater Drilling." Open Petroleum Engineering Journal 10, no. 1 (March 31, 2017): 48–63. http://dx.doi.org/10.2174/1874834101701010048.
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Background: The deepwater shallow formation has low fracture pressure and narrow safe window of mud density, which results in a high risk of wellbore instability in this kind of formation. Objective: Without considering the plastic state of shallow formation around the borehole or the influence of in-situ stress difference on wellbore stability, the prediction accuracy of the traditional wellbore stability analysis models are relatively low. This paper can provide a reliable method to accurately predict the safe window of drilling fluid density. Method: In this paper, the shallow formation around the borehole is divided into plastic zone and elastic zone considering it under non-uniform in-situ stress. The collapse pressure formula of shallow formation is derived by taking the shrinkage rate of the borehole as the instability criterion. The fracturing pressure calculation model of shallow sediment under non-uniform in-situ stress is derived by combining the theory of excess pore pressure and hydraulic fracturing. Conclusion: The calculated results indicate that the horizontal in-situ stress difference has a significant effect on the shape of the plastic zone, the shrinkage rate of borehole, collapse pressure and fracturing pressure. The calculated results are in good agreement with the field test results, and the prediction accuracy of this model is higher than that of other traditional models.
3
Chen, Yujia, Ao Li, Dingding Yang, Tianyu Liu, Xiaowei Li, Jun Tang, and Chenglin Jiang. "Study on the Interaction between Low-Viscosity High-Permeability Pregrouting Sealing Material and Coal and Its Application." Advances in Polymer Technology 2020 (February 12, 2020): 1–11. http://dx.doi.org/10.1155/2020/1217285.
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In order to ensure the intactness of pressure-measuring boreholes and the accuracy of gas pressure determination, pregrouting treatment with polymer materials is frequently applied to bedding drilling in coal mines. However, the existing polyurethane materials are of high viscosity, low permeability, and poor safety, bringing great difficulties to their field promotion and application. In view of this problem, after optimization and experiments, polylactide polyol/polyether polyol 4110/isocyanate was determined as the target system. Bio-based benzoxazine (Boz-F), red phosphorus, and melamine with a mass ratio of 2 : 1 : 2 were used as the flame retardant, which then underwent mechanical modification by hollow glass bubbles. Finally, the pregrouting material with low viscosity and high permeability was compounded, and its interaction with coal was experimentally studied. The results show that compared with traditional polyurethane, the new material increases the effective consolidation distance in the coal seam by 40% on average. Its permeation radius is also larger than the calculated radius of the plastic softening zone of a borehole. In addition, the strengths of coal-new material consolidated products with different ratios fully surpass those of coal-polyurethane material consolidated products. The enhancement of compressive strength and bending strength is up to 153% and 161%, respectively. The field application indicates that after pregrouting treatment of boreholes in the coal seam with the new material, the borehole formation rate reaches 100%. Therefore, the new material is safe and practical for gas pressure measurement through bedding drilling on site.
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Wang, Wen Cai, Hui Zhao, Hong Yu Zhao, and Qing Tian Zhang. "Characters of Electromagnetic Radiation in Coal and its Application in Forecast of Coal and Gas Outburst." Advanced Materials Research 962-965 (June 2014): 1051–55. http://dx.doi.org/10.4028/www.scientific.net/amr.962-965.1051.
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The coal can produce electromagnetic radiation when it is in the loading process. The electromagnetic radiation characteristics testing to the sample in the process of uniaxial compression failure in the lab shows that loading stress and the strength of electromagnetic radiation, the number of electromagnetic radiation pulse, the number of acoustic emission pulse are positively correlated relationship when it is in the loading process. They usually have a good corresponding relationship with each other, but are not completely synchronization. They test the corresponding relationship between the electromagnetic radiation intensity of coal and main parameters gas emission initial speed of traditional prediction of coal and gas outburst borehole and amount of drilling cuttings. The results show that the electromagnetic radiation intensity and gas emission initial speed of borehole and amount of drilling cuttings have a positive correlation, and the linear positive correlation equation is obtained. Thus it can be seen, electromagnetic radiation characteristics can be used for predicting the outburst of coal and gas.
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Zhao, Hong Shan, and Kun Zhang. "Field Test of Automated Strap-Down Vertical Drilling System in Well Anshun-1." Applied Mechanics and Materials 543-547 (March 2014): 387–90. http://dx.doi.org/10.4028/www.scientific.net/amm.543-547.387.
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Automated strap-down vertical drilling system (AVDS) with independent intellectual property rights is composed of a strap-down stabilization platform and a deviation control and correction mechanism. It performs deviation control and correction initiatively while drilling by applying dynamic push-lean, which can effectively solve the inclination control and fast drilling problems arising from high-steep structures and high dip formations. The system can release drilling pressure completely, so under the precondition of ensuring inclination precision, it could remarkably improve the penetration rate, shorten the drilling cycle and reduce the drilling costs. During the field test from 2436 to 2610.79m in well Anshun-1, inclination angle decreased to 0.25° from 6.25°. The average ROP was 1.02m/h, and the average footage was 87.4m. Compared with traditional drilling tools, it improved the penetration rate by 25.9% and the footage by 18.3%. The stability and reliability of the system was proved through the field test. It was suggested that field tests should be strengthened and AVDS applying for different borehole should be developed.
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Pan, Yue, Xiao He, Hao Chen, and Xiuming Wang. "Reflection signals and wellbore scattering waves in acoustic logging while drilling." Journal of Geophysics and Engineering 17, no. 3 (March 18, 2020): 552–61. http://dx.doi.org/10.1093/jge/gxaa014.
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Abstract In sonic logging while drilling (LWD), it is difficult to extract reflection signals for the goal of geo-steering as the wave fields are so complicated. It is important to analyse the reflection and scattering effects based on the synthetic acoustic signals of the real LWD models, while considering the medium discontinuity at the end of the borehole. We numerically investigate the acoustic LWD responses to reflective boundaries out of the borehole. To simulate the received signals, the 3D finite difference in time domain method is implemented. Mode conversions between the collar and the Stoneley waves are revealed. Strong reflections are generated at the bottom of the well, which can be equivalent to an additional scattering source (i.e. an apparent point source). The scattering waves by the wellbore bottom are generally much stronger than the reflections from the layer interfaces of formations. By comparing the models with stratified interfaces of opposite inclination directions, the propagation mechanisms of two newly recognised reflection waves are revealed in addition to the traditional body wave reflections (P and S waves) in LWD models. The energy of the collar wave radiates outside the borehole and then reflects at the bedding boundaries; meanwhile, the scattering waves from the well bottom can generate reflections too. These reflection arrivals match well with the time predicted by ray theories, respectively. Finally, we propose a possible means to estimate the dipping directions of geological interfaces by reflection waves emitted from both LWD transmitters and the apparent source at the well bottom.
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Sun, Pinghe, Junyi Zhu, Binkui Zhao, Xinxin Zhang, Han Cao, Mingjin Tian, Meng Han, and Weisheng Liu. "Study on the Mechanism of Ionic Stabilizers on Shale Gas Reservoir Mechanics in Northwestern Hunan." Energies 12, no. 12 (June 25, 2019): 2453. http://dx.doi.org/10.3390/en12122453.
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The shale of the lower Cambrian Niutitang formation in northwestern Hunan is an ideal reservoir for shale gas. There is a close connection between borehole stability and drilling fluid in shale gas drilling. Ionic stabilizer is a new type of stratum consolidation agent that inhibits the hydration expansion of clay minerals and improves mechanical strength of the borehole. The traditional idea of pore wall protection is to use drilling fluid additives to prevent shale from interacting with water. However, ionic stabilizer can change the hydrophilic of clay minerals in shale, making the particles become hydrophobic and dense, therefore, the formation stability can be enhanced simultaneously. The material used in this paper is different from the normal ionic stabilizer, some chemical bonds that have been changed in the new material called enhanced normality ionic (ENI) stabilizer. This paper utilized the shale samples those obtained from Niutitang formation to study the connection between ENI and the mechanical properties of shale. Mechanical tests and microscopic pore tests were performed on different samples which were soaked in water and the ENI with different concentrations. It has been found through tests that ENI can inhibit the development of shale pores, and as the concentration increases, the inhibition increases. In addition, as the ENI concentration increases, the uniaxial compressive strength and Young’s modulus of the shale increase, and the ratio of stability coefficients decreases. It can be concluded that the ENI can improve the mechanical strength of carbon shale, and prevent the development of rock damage. Moreover, it can improve the ability of rock to resist damage, and enhance borehole stability initiatively.
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Bordakov, Georgiy A., Alexander V. Kostin, John C. Rasmus, Denis Heliot, Harald Laastad, and Edward J. Stockhausen. "Improving LWD Image and Formation Evaluation by Utilizing Dynamically Corrected Drilling-Derived LWD Depth and Continuous Inclination and Azimuth Measurements." SPE Reservoir Evaluation & Engineering 12, no. 01 (February 26, 2009): 137–48. http://dx.doi.org/10.2118/109972-pa.
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Summary The paper illustrates the improvements in logging while drilling (LWD) images and subsequent formation evaluation by using a new methodology for depth and survey measurements corrections. LWD depth measurements are often considered inaccurate and, therefore, not as reliable for well-to-well correlations, correlations with data acquired with wireline measurements and formation layer thickness determinations. The reasons for these inaccuracies generally originate from the traditional practice that LWD depth is purposely made equal to the driller's depth, which is a static pipe length measurement made by tape at the surface. There is almost always a difference between the actual measured depth (MD) of the LWD sensor downhole and this static pipe measurement, because downhole the drillpipe is subject to an environment that is not representative of the derrick (e.g., varying drilling mechanical conditions and temperature changes). Here, we demonstrate the applications of the method, which allows dynamic driller's depth correction for the effects of drillstring weight, downhole friction, weight on bit, thermal expansion, residual rig heave, and tide. Another significant inaccuracy source is a standard practice of calculating borehole position from stationary survey points typically taken every 90 feet (ft) using the minimum curvature method. Neglecting the complex borehole shape between survey stations can lead to a systematic error in determining the borehole position. We consider using continuous inclination and azimuth measurements along with stationary surveys to correct these errors. We provide comparisons of LWD images before and after the depth and survey corrections to illustrate how the measurement errors affect formation dips interpreted from the images. We demonstrate how improved accuracy allows filtering out the artifacts and provides more decisive and accurate identification of geologic features. We show how using the corrected 3D position improves accuracy of the formation thicknesses calculations and therefore improves the reservoir summation results. As a result, we propose a borehole 3D position measurement that is accurate, consistent between wells (regardless of rig type or bottomhole assembly [BHA] configuration), and independent of the drilling mode. Using this new measurement significantly improves the quality of the formation evaluation.
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Liu, Sheng Hu, and Ya Min Xing. "Study on a Data Acquisition System for Logging while Drilling." Applied Mechanics and Materials 198-199 (September 2012): 1246–49. http://dx.doi.org/10.4028/www.scientific.net/amm.198-199.1246.
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This electronic Logging while drilling (LWD) is a new sort of well drilling technology developed in recent years. As to the traditional cable borehole survey, the LWD method has many advantages because of its higher accuracy, higher geologic strata resolution capacity, much less time and cost. To meet the current logging technology needs, A data acquisition and processing system for logging while drilling is designed．It minutely introduces the collection system structure, acquisition Program, the digital design of LWD and discusses the design and the implementation of each functional module．The system which designed on the basis of the high precise DSP and FPGA implements signal pretreatment, high speed A/D control and digitalization of the phase sensitive demodulation etc, optimizes the acquisition and processing system and supplies a new way for the development of logging while drilling．Experimental results show that system performance has attained the design requirement.
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Sudakov, Andrii, Andrii Dreus, Diana Sudakova, and Oleksandr Khamininch. "The study of melting process of the new plugging material at thermomechanical isolation technology of permeable horizons of mine opening." E3S Web of Conferences 60 (2018): 00027. http://dx.doi.org/10.1051/e3sconf/20186000027.
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The article presents the results of experimental and theoretical studies, the purpose of which was to substantiate the technology of drilling wells isolation using new thermoplastic composite material. The basis of the proposed material is gravel, and secondary polyethylene terephthalate acts as a binding material. The use of the proposed insulation material avoids a number of disadvantages specific for traditional grouting mortars. The technology of material application provides its melting in a well by thermomechanical drilling. The article deals with the issues, related to the substantiation of the optimal formulation of a thermoplastic composite material based on secondary polyethylene terephthalate, and the determination of rational operating parameters of thermomechanical drilling, which allow to melt effectively the material at the bottom of a well. The possibility of material application for the insulation of absorbing horizons in borehole conditions has been proved. Based on the analysis of the heat balance at the bottom of a well, the calculation procedure has been proposed and the dependences of the velocity and time of thermomechanical melting of the grouting thermoplastic composite material on the operating parameters of drilling, thermal properties and geometric characteristics of the drill bit, have been determined.
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Liang, Lin, Ting Lei, Adam Donald, and Matthew Blyth. "Physics-Driven Machine-Learning-Based Borehole Sonic Interpretation in the Presence of Casing and Drillpipe." SPE Reservoir Evaluation & Engineering 24, no. 02 (February 12, 2021): 310–24. http://dx.doi.org/10.2118/201542-pa.
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Summary Interpretation of sonic data acquired by a logging-while-drilling (LWD) tool or wireline tool in cased holes is complicated by the presence of drillpipe or casing because those steel pipes can act as a strong waveguide. Traditional solutions, which rely on using a frequency bandpass filter or waveform arrival-time separation to filter out the unwanted pipe mode, often fail when formation and pipe signals coexist in the same frequency band or arrival-time range. We hence developed a physics-driven machine-learning-based method to overcome the challenge. In this method, two synthetic databases are generated from a general root-finding mode-search routine on the basis of two assumed models: One is defined as a cemented cased hole for a wireline scenario, and the other is defined as a steel pipe immersed in a fluid-filled borehole for the logging-while-drilling scenario. The synthetic databases are used to train neural network models, which are first used to perform global sensitivity analysis on all relevant model parameters so that the influence of each parameter on the dipole dispersion data can be well understood. A least-squares inversion scheme using the trained model was developed and tested on synthetic cases. The scheme showed good results, and a reasonable uncertainty estimate was made for each parameter. We then extended the application of the trained model to develop a method for automated labeling and extraction of the dipole flexural dispersion mode from other disturbances. The method combines the clustering technique with the neural-network-model-based inversion and an adaptive filter. Testing on field data demonstrates that the new method is superior to traditional methods because it introduces a mechanism from which unwanted pipe mode can be physically filtered out. This novel physics-driven machine-learning-based method improved the interpretation of sonic dipole dispersion data to cope with the challenge brought by the existence of steel pipes. Unlike data-driven machine learning methods, it can provide global service with just one-time offline training. Compared with traditional methods, the new method is more accurate and reliable because the processing is confined by physical laws. This method is less dependent on input parameters; hence, a fully automated solution could be achieved.
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Li, Bo, Junxiang Zhang, Jianping Wei, and Qiang Zhang. "Preparation and Sealing Performance of a New Coal Dust Polymer Composite Sealing Material." Advances in Materials Science and Engineering 2018 (August 6, 2018): 1–10. http://dx.doi.org/10.1155/2018/8480913.
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In this study, a new coal-dust polymer composite material (CP) was fabricated to improve the borehole gas drainage effect and address the limitations of traditional sealing materials. This material used coal dust generated during underground drilling construction as filler, amino resin as binder, and also some other additives. Based on the orthogonal test scheme, 16 groups of experiments were conducted to investigate the effects of coal-dust content, water-material ratio, and cross-linking agent content on viscosity, 3-day (3-d) compressive strength, and gel time of the CP. The influences of the various factors were studied using a range of analytical methods to obtain the optimal proportion of the CP. Moreover, the mechanical property and microstructure of the CP were also analyzed to evaluate the sealing performance of this material. Results showed that this material exhibited obvious plastic characteristic and could provide an effective support for the borehole; it can adapt to the deformation of the borehole to some extent and achieve a long-term sealing effect. The scanning electron microscopy (SEM) results show a good correlation between the resin molecules and coal dust inside the material, which were conducive to improve the sealing performance of the CP material.
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Tong, Hua, Daqiang Guo, and Xiaohua Zhu. "Research on a probabilistic assessment criterion of casing deformation in an incomplete borehole in deep salt formation." Proceedings of the Institution of Mechanical Engineers, Part E: Journal of Process Mechanical Engineering 231, no. 3 (September 16, 2015): 444–54. http://dx.doi.org/10.1177/0954408915605975.
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Drilling and completing wells through complex salt formation is technically challenging and costing. Field data demonstrates that well casings designed by traditional safety coefficient criterion occurring failure in deep salt formation though their safety factors are greater than 1. To reveal the failure mechanism, a probabilistic computational model coupled with salt formation, defective cement and worn casing is established and analyzed using Monte Carlo simulation method. On the basis of reliability theory, the results calculated by 5000 times simulations show that the traditional safety coefficient criterion has been unable to adapt to the safety assessment of well casings under salt creep conditions. To gain a sophisticated evaluation, a new assessment criterion is established and applied to assess the security of well casings under salt creep conditions. This study provides a new perspective for revealing the failure mechanism and solutions of evaluation on well casings under salt creep conditions, which may be an alternative method to study and predict the life of well casings in deep complicated formation.
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Spicer, Bill. "Geophysical signature of the Victoria property, vectoring toward deep mineralization in the Sudbury Basin." Interpretation 4, no. 3 (August 1, 2016): T281—T290. http://dx.doi.org/10.1190/int-2014-0190.1.
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Exploration throughout KGHM International’s Victoria property in Sudbury, Ontario, occurred over an approximate 10-year period and resulted in the discovery of the Victoria Deposit. A variety of geophysical techniques were used with varying results to detect Cu-Ni-PGE-rich ore bodies at depth. Near-surface methods supplemented traditional mapping and geologic interpretation techniques to gain an understanding of property-scale depositional environments. The use of 3C borehole EM surveying facilitated the transition from a broad exploration program, which was based on surface geophysical signatures and geologic principles toward a targeted mineral definition campaign. The presence of off-hole features within several drillholes targeting a lesser massive sulfide lens identified a mass of strong conductors approximately 1 km deep. The drilling of thin-plate forward models derived from the borehole EMs resulted in the intersection of the Victoria Deposit. The tabular deposit has a downdip extent of more than 1500 m and remains open at depth. This significant discovery is an example of the opportunity that remains at depth within the Sudbury Basin, one of the world’s most prolific mining camps.
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Gao, Dewei, Jiajun Xie, Shengming Huang, Shenyao Wu, Pengcheng Wu, and Weian Huang. "Research and Application of Evaluation Methods for Functional Characteristics of Oil-Based Drilling Fluid in Shale Gas Wells." Geofluids 2021 (March 16, 2021): 1–9. http://dx.doi.org/10.1155/2021/8814032.
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Intelligent unconventional reservoir optimal production control technology is a comprehensive technology, involving geology, reservoir simulation, and efficient drilling and completion. Efficient drilling and completion provides a flow channel for unconventional oil and gas exploitation and a wellbore with good integrity for reservoir transformation, which is an important link in the efficient development of unconventional oil and gas. The application of industry standard method to evaluate the performance of oil-based drilling fluid has the problem of poor correlation. It cannot reflect the difference of performance among oil-based drilling fluid systems, which lacks the significance for field construction. Based on shale expansion, rolling dispersion experiment, and microporous membrane filtration loss test, the physicochemical mechanism of borehole wall instability in shale formation was investigated. The evaluation methods of shale lubrication, antiaccretion test, slake durability, buck hardness test, etc. are put forward, and the formula of oil-based drilling fluid is optimized. The lubrication and antiaccretion experiment method can effectively and intuitively characterize the cleaning and lubrication effect of drilling fluid on drilling tools. The slake durability evaluation method simulates the collision between drill cuttings and the drill string and well wall. The bucking hardness experiment is through testing the cuttings and the hardness change after drilling fluid action reflects its inhibitory effect. The new methods were used to evaluate the oil-based drilling fluid used in 4 wells in the Changning block. It was found that the drilling fluid of CN209H2 well adhered to the steel column with at least 0.41 g of cuttings; the recovery rate of the drilling fluid resistance of CN209H1 was up to 87.70%, and YX1200 oil-based drilling fluid plugging agent was selected through the microporous membrane experiment. In the process of drilling the well CN209H5, the new oil-based drilling fluid formulation improved the lubrication performance by 44%, accompanied by 95.48% recovery rate and less than 10 mL HTHP fluid loss at the same time. The research results show that the oil-based drilling fluid system optimized according to the new method can significantly inhibit shale hydration and dispersion and can effectively solve the problem of unstable performance of traditional oil-based drilling fluids in the Changning block.
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Kharitontseva, Polina, Andy Gardiner, Marina Tugarova, Dmitrii Chernov, Elizaveta Maksimova, Ilia Churochkin, and Valeriy Rukavishnikov. "An Integrated Approach for Formation Micro-Image Rock Typing Based on Petrography Data: A Case Study in Shallow Marine Carbonates." Geosciences 11, no. 6 (May 30, 2021): 235. http://dx.doi.org/10.3390/geosciences11060235.
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Core rock-typing (RT) is commonly used for creating geologically reliable models of porous media in carbonate reservoirs. This approach is more advanced than the traditional porosity–permeability relationship and is based on the division of carbonate rocks into groups, using common classifications (lithofacies, FZI, Winland–Pittman, etc.). These clustering methods can provide either geological or petrophysical descriptions of the identified rock types. Besides, the connection of identified core rock types with standard logs could be challenging due to the different scales of measurement. This paper considers the creation of a new approach, named “integrated rock-typing,” which connects geologically and petrophysically driven rock types using borehole image logs. The methodology was applied to an Upper Devonian–Lower Carboniferous carbonate field. The workflow comprises borehole image structural/textural analysis with vug fraction identification, quantitative geological descriptions from thin sections, and petrophysical measurements. The geological section is divided into six rock types, which were controlled by sedimentary and diagenetic processes. The created Rock Type Catalogue provides clear links between rock types and log data, including wells with standard suites of logs. The results will be useful for geological modelling and validation of the future drilling strategy for the studied field.
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Derbal, Massinissa, Mohamed Gharib, Shady S. Refaat, Alan Palazzolo, and Sadok Sassi. "Fractional-order controllers for stick-slip vibration mitigation in oil well drill-strings." Journal of Low Frequency Noise, Vibration and Active Control 40, no. 3 (January 11, 2021): 1571–84. http://dx.doi.org/10.1177/1461348420984040.
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Drillstring–borehole interaction can produce severely damaging vibrations. An example is stick–slip vibration, which negatively affects drilling performance, tool integrity and completion time, and costs. Attempts to mitigate stick–slip vibration typically use passive means and/or change the operation parameters, such as weight on bit and rotational speed. Automating the latter approach, by means of feedback control, holds the promise of quicker and more effective mitigation. The present work presents three separate fractional-order controllers for mitigating drillstring slip–stick vibrations. For the sake of illustration, the drillstring is represented by a torsional vibration lumped parameter model with four degrees of freedom, including parameter uncertainty. The robustness of these fractional-order controllers is compared with traditional proportional-integral-derivative controllers under variation of the weight on bit and the drill bit’s desired rotary speed. The results confirm the proposed controllers effectiveness and feasibility, with rapid time response and less overshoot than conventional proportional-integral-derivative controllers.
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Molohkov, Dmitry, Andy Pietsch, Jack Harfoushian, and Shahid Azizul Haq. "Application of formation pressure while drilling in Australia: North West Shelf examples." APPEA Journal 49, no. 2 (2009): 568. http://dx.doi.org/10.1071/aj08041.
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Since its introduction in the 1950s, the point-by-point wireline formation pressure measurement technique has been successfully used for formation evaluation and reservoir management, and has been an essential input into reservoir models. In exploration and appraisal wells, where depletion has not yet affected the reservoir, vertical pressure profiling can be used for fluid gradient determination that may be interpreted in terms of fluid densities and contacts. In a dynamic producing environment pressure measurements can help to identify vertical and horizontal boundaries and communication. Measurement of pressure distribution along the borehole was historically done with wireline instruments or, in difficult logging conditions, with wireline instruments conveyed by drill pipe. In some environments, especially in highly deviated and S-shaped wells or unconsolidated formations, drill pipe conveyance of wireline formation pressure testers introduces significant operational risk. Formation Pressure While Drilling (FPWD), introduced in 2003, offers a new cost-effective solution for gathering formation pressure data. FPWD is a new method to directly measure formation pore pressure as the well is being drilled, extending its application beyond traditional fluid typing, contacts and compartmentalisation determination to well control and drilling optimisation. The market for FPWD is developing rapidly with all major service companies providing their own implementations of the technology. The next step in the evolution of FPWD technology—sampling while drilling—is not commercially available yet, but this is just a matter of time. The case history presented in this extended abstract is an example of the application and lessons learned from the FPWD service used in one of the oil fields on the North West Shelf, Australia.
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Malik, Mayank, Scott A. Hanson, and Simon Clinch. "Tutorial: Maximizing Value From Mudlogs–Integrated Approach to Determine Net Pay." Petrophysics – The SPWLA Journal of Formation Evaluation and Reservoir Description 62, no. 1 (February 1, 2021): 4–15. http://dx.doi.org/10.30632/pjv62n1-2021t1.
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In the current business environment, operators are increasingly striving to reduce logging expenses when possible while maintaining safety of the drilling operations. Mudlogging has been remarkably successful through the oil industry downturn due to the value of information derived from the analysis as well as the relatively low cost. Information about the lithology and fluid content of the borehole during drilling is important for drilling optimization and qualitative petrophysical assessment. This tutorial takes mudlogs a step further to quantify net pay and estimate reserves in low-permeability reservoirs where traditional log analysis is challenging. Methods will be described for estimating gas-in-mud based on characterized gas measurement systems and obtaining bulk volume of gas per volume of rock drilled. Corrections are discussed for mud gas systems based on their mechanical operating parameters of mud flow into the gas extractor, gas sample suction rate out of the gas extractor, recirculated gas, and estimated gas extraction efficiencies. Applying these corrections yields normalized bulk gas volume and gas-oil ratio (GOR), which is calibrated with the petrophysical assessment from wireline logs and PVT samples. Finally, correlations between bulk hydrocarbon volume and permeability are used to estimate volumetrics. Case studies presented show that the calibrated mudlogs can be used for quantitative assessment of bulk volume of hydrocarbons in high-angle/horizontal wells where conveying wireline logs might be challenging. Pay flags computed from the mudlog interpretation can be used to guide completion decisions. Additionally, GOR estimates derived from mudlogs can be used for fluid typing and optimizing the fluid sampling program in deepwater development wells. Results presented clearly show that mudlogs can provide continuous, real-time, and quantitative petrophysical assessments.
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Ewusi, A., and J. Seidu. "Efficacy of Geophysical Techniques for Groundwater Exploration in the Volta Basin, Northern Region of Ghana." Ghana Mining Journal 20, no. 1 (July 7, 2020): 11–19. http://dx.doi.org/10.4314/gm.v20i1.2.
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Abstract
Groundwater, traditionally extracted from hand-dug wells and boreholes is the main drinking water source in the Northern Region of Ghana. Many boreholes have been constructed in the region to increase accessibility to potable water mainly as part of rural water supply projects where borehole siting has to be relatively cheaper. These projects have resulted in low success rates of borehole drilling because of the application of inefficient and simple geophysical techniques supposed to be cheaper. Field surveys were conducted with the Electrical Resistivity Imaging (ERI) technique, Electrokinetic System (EKS) sounding technique and Radon (222Rn) technique with the objectives of determining the best geophysical methods for borehole siting and its efficiency in the Volta Basin (VB) in the Northern Region of Ghana. The surveys were conducted at stations of existing dry and positive boreholes. Results show that the three geophysical techniques are efficient to identify groundwater accumulation zones. The ERI, EKS and 222Rn are efficient to identify discontinuities, calculate hydraulic conductivity of discontinuities and identify areas of water circulation respectively. It is recommended that the ERI be used to obtain discontinuities and weak zones for drilling on rural water supply projects in the VB. The EKS and 222Rn should be conducted to evaluate these features when high yield boreholes are required.
Keywords: Geophysical Techniques, Volta Basin, Borehole Drilling, Success Rates
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Sergei D., Viktorov, Zakalinskii Vladimir M., Shipovskii Ivan E., and Mingazov Rafael Ia. "New aspect of drilling development and application in today’s mineral extraction." Izvestiya vysshikh uchebnykh zavedenii. Gornyi zhurnal, no. 6 (September 24, 2020): 5. http://dx.doi.org/10.21440/0536-1028-2020-6-5-13.
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Introduction. The method of applying the factor of short period delay initiation in rock blasting and its effectiveness can be substantiated by the technical possibility of applying it for both conventional inter-row and current downhole delay intervals. The state of the art in blasting has made it possible to implement the technology of a short period delay. So it is rather relevant and extremely difficult to study of the technology’s aspects in full-scale production conditions. Methodology. This work analyzes the options for rock blasting and blasthole charges designs in order to find out how to implement them in a new and more effective way in modern conditions. A well-known method has been chosen, which combines the rock blasting method and the unconventional design of the blasthole charge. It is used as an example to demonstrate the possibility of expanding the practical range of the selected charge placement schemes. This work has been the first to introduce a hypothesis on the possibility of achieving the same effect in two different designs of blasthole charges, but "acting" in almost the same range of short period delay (SPD) use. The fact is that "vertical" distances between downhole short-delay detonators in a conventional blasthole charge (in this case, a single charge) and "horizontal" distances between parallel converged wells of a beam are almost the same. In this regard, it has become possible to focus not on its "internal" content on the "external" one and explain the features of these mechanisms by means of computer simulation. Due to the apparent specific character of conducting a blast in production conditions and intricate experimental observation, this approach is more realizable in practice and the only possible one. 12 "Izvestiya vysshikh uchebnykh zavedenii. Gornyi zhurnal". No. 6. 2020 ISSN 0536-1028 Results. It is proposed to test various methods of blasting (detonation) based on the idea of replacing (transforming, transferring) the explosion action of detonators ( ≥ 1) in a single well charge (conventionally large diameter) with the detonation of ( ≥ 1) lines of a beam of converged borehole charges of the corresponding small diameter. As soon as the number of beam charge design options increases, the range of research options that can lead to the results with improved quality expands significantly. To achieve this goal, the action of various configurations of charges with in-line short period delay blasting in a beam was studied. It should make it possible to come up to some recommendations for blast control. Summary. On the one hand, the proposed blast patterns show the technological departure from the traditional circular shape of the blast wave, on the other hand, they allow using the effect found in the course of numerical experiment for various purposes, in particular, to ensure blasting effect on (interaction with) design features of various mining methods and production systems in complex geomechanical environment
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Ivanov, Olexandr, Pavlo Prysyazhnyuk, Liubomyr Romanyshyn, Taras Romanyshyn, and Yurii Mosora. "Using FCAW with Electrodes Based on Fe-Ti-Mo-B-C System for Increasing of Durability of Junk Removal Tools." Multidisciplinary Aspects of Production Engineering 4, no. 1 (September 1, 2021): 132–41. http://dx.doi.org/10.2478/mape-2021-0012.
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Abstract In this work were analyzed factors and working conditions that leads to the wearing of junk mills tools that are a part of junk removal equipment used in drilling and workover of borehole. Such equipment is a part of oil and gas industry and work under condition of intense abrasive wearing with increased pressures and cyclic loads. Was established that traditional hardfacing materials based on the Fe-Cr-C system are not effective for improvement of abrasion resistance of elements of such equipment due to their low crack resistance and low hardness of chromium carbides. The aim of this work was to increase a durability of that equipment by using of flux cored electrodes with reaction components of pure metal powders, which leads to forming the fine-grained structure with increased hardness. Powders of Ti, Mo, B4C and their combinations were used. Structures of the hardfacing coatings were investigated by method of metallography, scanning electron microscopy (SEM). Abrasion wear tests were held under condition of fixed and non-fixed abrasion. Using of pure metal powders led to formation of a fine-grained structure with grains of Mo2FeB2 that forms around TiC, which work as modifier. It was investigated that the researched material based on Fe-Ti-Mo-C-B system that was used for increasing the wear resistance of junk mills led to increasing of the TBO period in 1.5-1.6 times comparing with serial hardfacing materials based on tungsten.
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Pirie, Iain, Jack Horkowitz, Gary Simpson, and John Hohman. "Advanced methods for the evaluation of a hybrid-type unconventional play: The Bakken petroleum system." Interpretation 4, no. 2 (May 1, 2016): SF93—SF111. http://dx.doi.org/10.1190/int-2015-0139.1.
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Hybrid-type plays such as the Bakken petroleum system (BPS) can be particularly challenging from an interpretation, completion, or production perspective due to the mix of conventional and unconventional elements coexisting within a relatively short depth interval. In the BPS, conventional aspects include the presence of separate reservoir intervals, which, depending on your location within the basin, may include the Scallion, Middle Bakken, Sanish, and Three Forks. Unconventional aspects include the Lower Bakken and Upper Bakken shales, which are organic-rich shales comprising source rock and reservoir. Developing an accurate petrophysical evaluation of these formations requires a priori knowledge of the mineralogy, fluids, and geomechanical properties such that appropriate logging measurements, core analysis methods, and interpretation techniques can be obtained and used. During the development phase of an oil field, the log and core measurements being acquired and the petrophysical evaluation being performed may vary significantly from well to well across the field. Some wells may have triple-combo wireline or logging-while-drilling measurements consisting of bulk density, neutron porosity, and induction or laterolog resistivity, supplemented with a total gamma ray measurement. Borehole sonic logs may also have been acquired in some wells primarily for seismic calibration, geomechanical modeling, and hydraulic stimulation design. If the “standard” suite of measurements and petrophysical evaluation being provided fail to accurately represent the true complexity of the formations being evaluated, the asset valuation will, in most cases, be negatively impacted. Our formation evaluation of the BPS led to the identification of unique petrophysical challenges for each of the formations comprising the BPS. Traditional formation evaluation methods were applied to the BPS based on triple-combo measurements, a traditional petrophysical analysis, and the evaluation of net feet of pay. Advanced evaluation methods and techniques were then applied to address the petrophysical complexities identified with core evaluation, advanced log measurements, and discrepancies between the two. New petrophysical models were developed and fine-tuned to address the shortcomings of the simple models, and the net feet of pay were reevaluated using these new models. The detailed formation evaluation program used to characterize the BPS consisted of standard triple-combo logs supplemented with advanced downhole measurements including: (1) triaxial resistivity for thin-bed analysis, (2) nuclear magnetic resonance for porosity, free-fluid, and kerogen identification, (3) dielectric dispersion for water saturation, (4) geochemical spectroscopy for mineralogy and total organic carbon, and (5) dipole sonic for dynamic rock properties. Petrophysical models were developed using deterministic and probabilistic methods to integrate the measurements acquired for the most accurate analysis of porosity, saturation, and mineralogy and to best describe the hydrocarbon production potential of the BPS.
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Whitby, David, Budi Utama, and Richard Reading. "Total Depth Solutions' technologies provide effective, efficient and safe well construction method to mitigate borehole problems." APPEA Journal 51, no. 1 (2011): 459. http://dx.doi.org/10.1071/aj10029.
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Permit TL/2 in the Carnarvon Basin, WA, presents several challenges for top hole drilling and casing running operations. Previous experience showed that drilling the 16” hole section and running 13⅜” casing was typically a time consuming phase of the well due to fluid losses and tight hole conditions, consequently requiring the use of seawater to drill, back reaming, wiper trips and occasional spotting of pills. The initial solution delivered to the operator as an alternative method to get 13⅜” casing to total depth (TD) was to employ a casing drill bit to ream the casing to bottom while also delivering an improved drill-out time. This would be coupled with a sophisticated, unique, reliable and simply operated top drive casing running system that was already installed on the rig. Reviewing the Weatherford Total Depth Solutions teamâs systems with cost, time and capabilities analysis, the operator was certain that the application of a complete drilling with casing system (DwC™) would mitigate the known hole problems and yield a safe and more cost-effective surface hole operation, significantly reducing non-productive time (NPT). This paper reviews: the problems that were traditionally encountered during conventional surface hole drilling and casing running operations; the decision-making process that the operator followed prior to employing DwC technology; and, the hazard mitigation and economic benefits realised through a one-way trip to total depth of about 1,000 m TVDRT, which broke to date the longest Weatherford 13⅜” DwC interval globally by the service company and operator.
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Neville, Thomas James, Geoff Weller, Ollivier Faivre, and Haitao Sun. "A New-Generation LWD Tool With Colocated Sensors Opens New Opportunities for Formation Evaluation." SPE Reservoir Evaluation & Engineering 10, no. 02 (April 1, 2007): 132–39. http://dx.doi.org/10.2118/97224-pa.
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Summary A new logging-while-drilling (LWD) tool that combines traditional measurements of gamma ray, propagation resistivity, gamma-gamma density, and thermal-neutron porosity with measurements unique to the LWD arena, including neutron capture spectroscopy and capture cross section, opens up new opportunities for formation evaluation on LWD. The compact design of the new-generation LWD tool greatly increases the likelihood that measurements will be made before the onset of significant invasion. The colocation of resistivity- and neutron-based sensors also means that key measurements are being made at the same depth at the same time and on a similar volume of the formation. These features ensure that all measurements are essentially seeing the same amount of invasion, thus removing a major complication in conventional LWD interpretation. Introduction A new-generation LWD tool has been developed that integrates measurements of gamma ray, propagation resistivity, gamma-gamma density, and thermal-neutron porosity with additional measurements unique to the LWD arena, including neutron capture spectroscopy and measurement of formation capture cross section (Weller et al. 2005). The EcoScope multifunction LWD service integrates all of these measurements in a single collar optimized to:Minimize measurement distance to bit.Improve real-time data-transmission rates.Improve service reliability.Minimize use of chemical nuclear sources. The new-generation LWD tool is currently available in a 6¾-in. collar size, with a total length of 26 ft (Fig. 1). The tool is rated to operate at up to 20,000 psi and 300°F. Other collar sizes are also under development to allow the tool to be deployed in a wider variety of hole sizes. Array propagation resistivity measurements and neutron-based measurements, including neutron porosity, neutron capture spectroscopy, and formation capture cross section, are colocated in the top half of the tool, with the highest measure point being less than 16 ft above the bottom of the tool. The conventional stabilized gamma-gamma density measurement is located within 8 ft of the bottom of the tool; this provides average and quadrant values and 16-sector images of bulk density and photoelectric factor. Stabilizers are available to support use in hole sizes ranging from approximately 8 to 10 in. Future developments of the tool will extend this range. Adjacent to the stabilizer are two diametrically opposed ultrasonic standoff sensors. These provide a 16-sector ultrasonic borehole image when the tool is rotating and allow for a caliper measurement even when sliding. Finally, an azimuthal gamma ray measurement device, capable of producing 16-sector gamma ray images as well as quadrant and average gamma ray measurements, is located only 5 ft above the bottom of the tool. The gamma ray detector uses a very large sodium iodide crystal to achieve high count rates, and owing to a focused design, the measurement has good azimuthal sensitivity; this enables gamma ray images to be acquired. Efforts to address the four objectives described above have led to the design of a tool with unprecedented application for formation evaluation. We will discuss here the application of the rich data set produced by this tool for the evaluation of lithology and mineralogy, porosity, and fluid saturations. Evaluation of these properties using a similar suite of measurements acquired while using wireline-logging tools has been presented previously (Herron et al. 2002). However, the suite of measurements available with this new tool, and the fact that many of the measurements are colocated, has allowed this methodology to be extended and enhanced. In addition, recent enhancements in data-transmission rates allow all of these measurements to be accessed in real time, thus bringing the possibility to use advanced formation-evaluation results to make while-drilling decisions.
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Lackowski, Marcin, Marek Tobiszewski, and Jacek Namieśnik. "Novel Desorber for Online Drilling Mud Gas Logging." Journal of Analytical Methods in Chemistry 2016 (2016): 1–9. http://dx.doi.org/10.1155/2016/7014068.
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This work presents the construction solution and experimental results of a novel desorber for online drilling mud gas logging. The traditional desorbers use mechanical mixing of the liquid to stimulate transfer of hydrocarbons to the gaseous phase that is further analyzed. The presented approach is based on transfer of hydrocarbons from the liquid to the gas bubbles flowing through it and further gas analysis. The desorber was checked for gas logging from four different drilling muds collected from Polish boreholes. The results of optimization studies are also presented in this study. The comparison of the novel desorber with a commercial one reveals strong advantages of the novel one. It is characterized by much better hydrocarbons recovery efficiency and allows reaching lower limits of detection of the whole analytical system. The presented desorber seems to be very attractive alternative over widely used mechanical desorbers.
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Sullivan, M. J., D. L. Belanger, and W. F. Stewart. "Use of Carbon/Oxygen Logs Run in Open Hole in Wells Drilled With Oil-Based Muds." SPE Reservoir Evaluation & Engineering 5, no. 01 (February 1, 2002): 60–67. http://dx.doi.org/10.2118/76643-pa.
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Summary Carbon/oxygen (C/O) logs have been run in open hole to assess zones that are potentially swept with fresh injection water in several infill wells offshore Cabinda, Angola. Interpretation of these logs has been challenging because of the invasion of oil-based mud (OBM) filtrate, mixed sand/carbonate lithology, variable water salinity, large boreholes, and lack of clean wet zones in which to normalize. We discuss the impact of these factors and our experiences in managing them. An example is included in which the results of time-lapse logging suggest that the invasion of OBM filtrate in water zones dissipates slowly or not at all. We show comparisons between saturations derived from the resistivity and the C/O ratio (COR) for these various conditions. Introduction The Angola Block 0 concession comprises new and mature reservoirs in an offshore operating environment. Waterflood operations are being used in several of these reservoirs to enhance recovery. Because the injected water has a relatively low water salinity (33 kppm NaCl equivalent seawater), detection of zones experiencing injection-water breakthrough is difficult when using traditional pulsed neutron capture (PNC) logging tools, which respond to the chloride ions in saline formation waters. One technique frequently employed in these circumstances is the use of C/O logging tools. These tools measure the relative abundance of carbon and oxygen, thereby distinguishing oil from water independent of salinity. These tools are usually run in cased hole in existing wells that have been on production for some time. In some fields, however, active infill drilling programs are under way in which new wells are drilled through producing horizons that may already have been swept with low-salinity injection water. These swept layers can be difficult to distinguish from oil-bearing intervals using conventional resistivity logs. Recently, C/O logging tools have been run in open hole as part of the standard openhole logging program. This has proven to be an effective means of distinguishing oil from low-salinity water before casing the well, despite the influence of mud-filtrate invasion. Peripheral waterflooding is under way or planned for many of the active developments. Most of the current waterflood activity is within the Vermelha formation, which is a complex lithology reservoir with variable amounts of sand, shale, and carbonate (dolomite with minor amounts of calcite and siderite) contained in the rock matrix. Reservoir surveillance in the early life of these fields centered around monitoring injection-well profiles and identifying water breakthrough in producers with production logs and PNC logs. Layer pressures are tracked with wireline formation tester data whenever an infill well is drilled. These data are used with fullfield reservoir simulations to track and predict water movement in the reservoir and develop infill drilling strategies. PNC logs provide accurate water-saturation information until low-salinity injection water reaches a logged well. Arrival of low-salinity injection water can be identified by a drop in produced water salinity, but it is impossible to tell which interval contributes the low-salinity injection water. Production-profile logs continue to provide valuable information after floodwater breakthrough occurs in the perforated intervals, but water saturation from PNC logs is no longer reliable. When low-salinity injection-water breakthrough is suspected (in perforated or unperforated sections), a C/O log is substituted for the PNC log to provide a salinity-independent means of determining water saturation.1–4 Despite the efforts to track the flood front and drill infill wells in unswept areas of the reservoir, there is a chance that breakthrough has already occurred in some of the proposed completion intervals. Most Block 0 wells are on gas lift, so minimizing water production is vital to maximizing oil production. The best way to minimize water production is to identify floodwater breakthrough during the openhole log analysis and complete only intervals that have not been swept by the waterflood. Standard Archie water-saturation analysis, based on resistivity and porosity, requires knowledge of the formation water resistivity (Rw). In a waterflood environment, the water resistivity can be variable, which adds considerable uncertainty in the computed water saturation. A salinity-independent means of determining water saturation, or at least discriminating fresh water from oil, has a significant impact on perforation selection. We were initially skeptical that reasonable C/O measurements could be made in an open hole with OBM because the borehole signal is an order of magnitude greater than the formation signal. When using OBM, small variations in the borehole size could produce a C/O response roughly equivalent to the response from oil in the formation.5 To date, we have run and confidently interpreted C/O data recorded with the 3.63-in.-diameter Pulsed Spectral Gamma Tool in 11 open and cased wellbores drilled with OBMs. Impact of Uncertainty in Water Salinity on Net Pay and Perforation Decisions The salinity of the Vermelha formation water is 200 kppm NaCl equivalent. Rw=0.025 ohm-m at 140°F (60°C). The formation water resistivity is higher in intervals in which floodwater breakthrough has occurred because of the presence of fresh floodwater. A conservative strategy for avoiding water production would be to assume floodwater might be present in any interval and compute Sw with a formation water resistivity that matches the floodwater. All intervals that still meet the Sw cutoff criterion are definitely pay, and there is no risk of producing water unexpectedly. The downside of this strategy is that some intervals that could have contributed water-free production will be eliminated. These intervals would pass the Sw cutoff criterion if 200 kppm water were actually present but would not pass the Sw cutoff criterion if 40 kppm water were present. An example of the impact of this is summarized in Table 1. The net pay calculated for Well TK-E10 is 375 ft assuming 200 kppm water and 250 ft assuming 40 kppm water. The difference of 125 ft represents 11.2 million bbl of oil in place (Sw=0.30, porosity=0.30, Bo=1.17). The value of the C/O log (or any log that can confirm the presence of fresh water) is tied to how much of this possible fresh water can be identified and avoided when perforating.
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Marsh, Roger, Abbas Khaksar, Oliver Gaede, Adrian White, Chris Wilson, and Scott Alexander. "Well integrity and the correlation between borehole breakouts, drilling-induced tensile fractures and cement-bond log response." APPEA Journal 52, no. 2 (2012): 696. http://dx.doi.org/10.1071/aj11110.
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Traditionally, image logs are acquired for sedimentary and structural analysis and more recently geo-mechanical analysis. Caliper logs are usually acquired for cement volume information and borehole condition information with pad tools. In general, cement bond logs have been the only logs used for the assessment of cement bond quality and thereby well integrity at the end of the well construction phase. Cement bond logs occasionally produce puzzling results—the cement job parameters indicate a successful cement job, yet the cement bond log indicates otherwise. In some circumstances, the presence of a micro-annulus can cause the appearance of a bad bond. In others, the causes of such cement bond log responses are less obvious. Wellbore breakouts and drilling induced tensile fractures can cause drilling problems such as increased losses, washouts and cave-ins; however, their association with cement bond quality is not always appreciated. This dataset consists of LWD StarTrak and Lithotrak caliper data and EWL Wellbore Geometry Instrument (WGI) data and Segmented Bond Tool (SBT) data The data shows extensive zones of borehole breakouts as well as tensile fractures, some of which exist in areas without breakouts. The SBT pad data shows large areas of poor bond between relatively thin-cemented sections. The VDL data shows formation arrivals that became more pronounced with depth. When the data are compared, the zones that showed tensile fractures coincided with zones showing poor bond. The zones showing no tensile fractures or breakouts were also the zones showing good cement bond.
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Pla´cido, Joa˜o Carlos R., He´lio M. R. Santos, and Yadira Diaz Galeano. "Drillstring Vibration and Wellbore Instability." Journal of Energy Resources Technology 124, no. 4 (November 20, 2002): 217–22. http://dx.doi.org/10.1115/1.1501302.
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Wellbore instability can be attributed to several causes. The ones thought to be most important include: chemical interaction with the drilling fluid, high tectonic stresses, and insufficient mud weight. Drillstring vibration, although not traditionally addressed as a potential cause, might influence the stability of wellbores drilled in specific formations. Evidence of the strong correlation between severe vibration and wellbore instability has been reported in the literature. However, a more thorough understanding of the phenomenon is still lacking. This paper describes a study that has been developed by PETROBRAS focusing on how drillstring vibration impacts wellbore instability. Vibration has been monitored in some wells, and events related to borehole enlargement were observed. Four field cases are presented showing a strong correlation between high vibration level and wellbore enlargement in different lithologies. Other sources of wellbore enlargement have also been identified, and they can be clearly separated from vibration.
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Stryczek, Stanisław, Rafał Wiśniowski, Andrzej Gonet, and Albert Złotkowski. "Influence of Specific Surface of Lignite Fluidal Ashes on Rheological Properties of Sealing Slurries / Wpływ Powierzchni Właściwej Popiołów Fluidalnych z Węgla Brunatnego na Właściwości Reologiczne Zaczynów Uszczelniających." Archives of Mining Sciences 57, no. 2 (November 12, 2012): 313–22. http://dx.doi.org/10.2478/v10267-012-0019-0.
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Abstract New generation fly ashes come from the combustion of coal in fluid-bed furnaces with simultaneous sulphur-removal from gases at ca. 850°C. Accordingly, all produced ashes basically differ in their physicochemical properties from the traditional silica ones. The aim of the laboratory analyses was determining the influence of specific surface and granular composition of fluidal ash on rheological properties of slurries used for sealing up the ground and rock mass media with hole injection methods, geoengineering works and cementing casing pipes in deep boreholes. Fluidal ash from the combustion of lignite contain active Puzzolan appearing in the form of dehydrated clayey minerals and active components activating the process of hydration ashes, i.e. CaO, anhydrite II and CaCO3. The ashes have a weak point, i.e. their high water diment, which the desired rheological properties related with the range of their propagation in the rock mass cannot not be acquired for injection works in the traditional sealing slurries technology. Increasing the water-to-mixture ratio should eliminate this feature of fluidal ashes. Laboratory analyses were performed for slurries based on metallurgical cement CEM III/A 32,5 having water-to-mixture ratios: 0.5; 0.6 ; 0.7 and 0.8; the fluidal ash concentration in the slurries was 30 wt.% (with respect to the mass of dry cement). Basing on the obtained results there were determined optimum recipes of sealing slurries in view of their rheological parameters which could be applied both in drilling technologies (cementing casing pipes, closing of boreholes, plugging) and in geoengineering works related with sealing up and reinforcing ground and rock mass media.
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Kabirzadeh, Hojjat, Elena Rangelova, Gyoo Ho Lee, Jaehoon Jeong, Ik Woo, Yu Zhang, and Jeong Woo Kim. "Dynamic Error Analysis of Measurement While Drilling Using Variable Geomagnetic In-Field Referencing." SPE Journal 23, no. 06 (October 17, 2018): 2327–38. http://dx.doi.org/10.2118/188653-pa.
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Summary The safe and economical determination of a wellbore trajectory in directional drilling is traditionally achieved by measurement-while-drilling (MWD) methods, which implement magnetic north-seeking sensor packages. Inaccuracies in the determination of well path arise because of random and systematic errors in the measurements of the sensors. Multistation analysis (MSA) and magnetic in-field referencing (IFR) have already demonstrated the potential to decrease the effects of errors because of magnetization of drillstring components along with variable errors caused by irregularities in the magnetization of crustal rocks in the vicinity of wells. Advanced MSA methodologies divide a borehole into several sections and use the average reference values of the total magnetic field, declination, and dip angle for analysis of errors in each section. Our investigations indicate that the variable-reference MSA (VR-MSA) can lead to a better determination of errors, specifically in areas of high magnetization. In this methodology, magnetic reference values are estimated at each station using forward and inverse modeling of surface-magnetic observations from IFR surveys. The fixed errors in magnetometer components are then calculated by minimizing the variance of the difference between the measured and unique estimated reference values at each station. A Levenberg-Marquardt algorithm (LMA) is adopted to solve the nonlinear optimization problem. Examination of this methodology using MWD data confirms more than 20% improvement in well-path-determination accuracy by comparing the results with the corrected path from the conventional MSA method and gyro surveys.
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Walker, M. J. "ADVANCES IN WIRELINE DATA ACQUISITION IN SYNTHETIC-BASED MUD SYSTEMS AND STRATEGIES FOR IMPROVED FORMATION EVALUATION." APPEA Journal 39, no. 1 (1999): 475. http://dx.doi.org/10.1071/aj98028.
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With the growth in popularity of synthetic-based mud (SBM) systems in Australia, and the emergence of more advanced wireline logging tools, there is an expectation that better hole conditions will give rise to better value- for-money evaluation programs. This is certainly true from the drilling cost perspective, where a logging job can be completed without need for 'wiper' trips to recondition the hole. However, in order to extract maximum value from the latest generation of logging tools, careful attention needs to be applied to the formation evaluation program.There have been some unexpected results from the wireline data quality viewpoint, with some positive results mixed with outcomes that fell below expectation, both linked to the complex nature of the synthetic-based mud recipes. Contrary to intuition, good quality electrical images may be obtained in synthetic-based muds, and some mud additives used to stop filtrate loss can seriously degrade the quality of acoustic images that are traditionally run in SBMs. Nuclear Magnetic Resonance works well in SBMs, especially where invasion is kept to a minimum. Holes drilled with SBMs do not normally display borehole ellipticity, which may be used to infer tectonic stress directions. However, oriented cross dipole shear-weave logging is able to detect azimuthal anisotropy, which may be related to tectonic stress, in holes with a circular profile.There are trade-offs using different SBM recipes, which will impact on formation evaluation programs. Close consultation with the logging contractor and mud company, as far ahead of the drilling of the well as possible is recommended to ensure a satisfactory outcome.
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Marc, Sohounou, Vissin Expédit Wilfrid, Sintondji Luc Olivier, Houssou Christophe S., Agbossou K. Euloge, and Edorh A. Patrick. "Physico-Chemical and Microbiological Qualities of Water From Wells, Drillings and Tanks Used as Drinking Water in the Municipality of Allada (Benin, West Africa)." European Scientific Journal, ESJ 13, no. 15 (May 31, 2017): 69. http://dx.doi.org/10.19044/esj.2017.v13n15p69.
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Water, source of life, is also a source of disease when it is polluted. The aim of this study is to analyze the physicochemical quality and the bacteriological quality of the wells, boreholes and tank for drinking water in the Commune of Allada. The methodology is based on the collection of data, data processing and analysis carried out at the Laboratory for Quality Control of Water and Food (LCQEA) of the Ministry of Health. From the water sampling carried out at three (03) traditional wells, two (02) boreholes, two (02) tanks and water of river (02), bacteriological and physicochemical analysis were performed. The results showed that pH is higher at the tank than other water sources. Well 3 (P3) has a very high electrical conductivity (EC) which was 384.95 μS / cm and 192.47 mg / L for total dissolved solids (TDS). The tank 2 exhibited high value in pH 9.14; 71.72 (μS / cm) for the electrical conductivity (CE) and 35.86 mg / L, in total dissolved solids (TDS). Well 2 (P2) has a high turbidity of 4.53 (NTU) at all analyzed water points. The concentration of iron, copper nickel and cobalt remains low(less than 0.4 mg / L).Wells 2 and tank 1 are concentrated in lead, respectively 20.75mg / L and 13.71mg / L. Tank 1 and 2 have a high concentration of cadmium compared to other water points. The presence of Escherichia coli with a high concentration at home SONEB (39 CFU) and at well 2 (7.10 2 ) was found. In view of these results some recommendations were made.
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Riedel, Marko, Calin Cosma, Nicoleta Enescu, Emilia Koivisto, Kari Komminaho, Katri Vaittinen, and Michał Malinowski. "Underground Vertical Seismic Profiling with Conventional and Fiber-Optic Systems for Exploration in the Kylylahti Polymetallic Mine, Eastern Finland." Minerals 8, no. 11 (November 20, 2018): 538. http://dx.doi.org/10.3390/min8110538.
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Seismic reflection methods have been used for the exploration of mineral resources for several decades. However, despite their unmatched spatial resolution and depth penetration, they only have played a minor role in mineral discoveries so far. Instead, mining and exploration companies have traditionally focused more on the use of potential field, electric and electromagnetic methods. In this context, we present a case study of an underground Vertical Seismic Profiling (VSP) experiment, which was designed to image a (semi-)massive sulfide deposit located in the Kylylahti polymetallic mine in eastern Finland. For the measurement, we used a conventional VSP with three-component geophones and a novel fiber-optic Distributed Acoustic Sensing (DAS) system. Both systems were deployed in boreholes located nearby the target sulfide deposit, and used in combination with an active seismic source that was fired from within the underground tunnels. With this setup, we successfully recorded seismic reflections from the deposit and its nearby geological contrasts. The recording systems provided data with a good signal-to-noise ratio and high spatial resolution. In addition to the measurements, we generated a realistic synthetic dataset based on a detailed geological model derived from extensive drilling data and petrophysical laboratory analysis. Specific processing and imaging of the acquired and synthetic datasets yielded high-resolution reflectivity images. Joint analysis of these images and cross-validation with lithological logging data from 135 nearby boreholes led to successful interpretation of key geological contacts including the target sulfide mineralization. In conclusion, our experiment demonstrates the value of in-mine VSP measurements for detailed resource delineation in a complex geological setting. In particular, we emphasize the potential benefit of using fiber-optic DAS systems, which provide reflection data at sufficient quality with less logistical effort and a higher acquisition rate. This amounts to a lower total acquisition cost, which makes DAS a valuable tool for future mineral exploration activities.
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Xia, Tong-qiang, Ke Gao, Hong-yun Ren, Jiao-fei He, and Zi-long Li. "Network Design Mode of In-Seam Gas Extraction Parameters Using Mathematical Modelling—Take Tangan Colliery as an Example." Geofluids 2020 (November 10, 2020): 1–12. http://dx.doi.org/10.1155/2020/8886068.
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Gas extraction is a practical and effective way to guarantee mining-process safety and deliver greater environmental benefits through reducing greenhouse gas emissions and increase the supply of a valuable clean gas resource. It has been effective in recent years, however it still has a series of problems that need to be solved. Gas extraction design mainly relies on engineering experience rather than quantitative design, resulting in low input-output ratio of gas extraction because of unreasonable design. How to build a bridge of communication between engineers and scientists is the key to realize scientific gas extraction. In this work, taking our previous gas-coal and gas-coal-heat coupling models of gas extraction as the theoretical basis, a new communication and design concept—an engineering design platform for gas extraction—is proposed using the network mode. Through the platform, on- and off-line interactions between service centre (scientific workers) and design objects (enterprises or individuals), such as data transmission, material review, scheme design and reviews, and so on. It greatly improves the efficiency and standardization of gas extraction design. Appling the networked platform, the gas extraction engineering parameters were quantitatively designed in the working face of 3307, Tangan colliery. According to the extraction time, the working face was divided into 6 extraction units. The number of boreholes were 763, the drilling capacity of coal was 0.03 m/t, and the extraction rate of each unit was more than 25%. The networked mode of in-seam gas extraction design would transform the traditional experience to the quantitative mode.
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Jackson, Charlie. "Tutorial: A Century of Sidewall Coring Evolution and Challenges, From Shallow Land to Deep Water." Petrophysics – The SPWLA Journal of Formation Evaluation and Reservoir Description 62, no. 3 (June 1, 2021): 230–43. http://dx.doi.org/10.30632/pjv62n3-2021t1.
Full textAbstract:
Due to the high cost of conventional coring operations, rotary sidewall coring has become increasingly important, particularly for deepwater operations. The rig costs, operational challenges, and amount of time involved to core wells below 30,000 ft are considerable, even for wireline operations. As wells get deeper, formation pressures will exceed 30,000 psi, and differential pressures can exceed 10,000 psi, which will eclipse the capabilities of traditional rotary coring tools. New technology has been introduced to enhance the recovery of rotary sidewall cores to improve operations and capabilities on these challenging wells that will be the primary subject of this paper. This new technology can also enhance coring operations and reliability for land and other offshore operations, in addition to deep water. New improvements and challenges include: * Reliable 1.5-in.-diameter core samples, with a 35,000-psi-rated tool * New high-powered coring tools with enhanced energy to address cutting Lower Tertiary wellcemented formations (Wilcox, Lower Miocene, etc.) * Higher torque and horsepower at the bit to enhance cutting and prevent stalling when coring * High-powered surface systems along with highstrength and high-power wireline cables * Upgrades to address high temperatures, highdifferential pressures, high-mud viscosity, large (24 in.) boreholes, and improved reliability * New drill bits and catcher rings to use a high-power system and operate in harsh coring environments * New cutting, retrieval, and core handling advancements for reliability in hard, consolidated formations * Combinability upgrades to reduce wireline trips and reduce rig costs for coring * Dual-coring tools with the ability to have different catcher rings and bits downhole simultaneously on a single run, along with tool redundancy downhole for improved reliability * Combination of rotary coring and formation sampling operations to obtain formation pressures, fluid samples, and rotary sidewall cores on a single run * Downhole monitoring of the coring operation, which includes drilling functions like torque, bit force, penetration rate, core bit penetration, and recovered core length, along with tool orientation * Core recovery information to enable 100% core verification downhole, so extra cores are not cut unnecessarily during the job, with individual core plugs measured and verified downhole * A unique method to seal the cores in a pressurecompensated coring tube downhole to capture all the formation fluids in the rock in downhole conditions * Complete rotary coring downhole operations can be monitored remotely for offsite interaction during the coring operation Besides reviewing historical coring tools and techniques, new technology is also discussed in more detail. The new technology starts with the introduction of the 1.5-in.-diameter rotary sidewall coring tools for deep water over a decade ago. Many applications and technologies are presented to show their effectiveness for deepwater operations. The successful examples include acquiring 1.5-in. cores in large boreholes, hard formations, deep wells, high-differential pressures, and extreme hydrostatic pressure. There are also examples of new technology available for future operations, including dual coring, combination coring, and sealed pressurized coring.
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Schiøler, Poul, Jan Andsbjerg, Ole R. Clausen, Gregers Dam, Karen Dybkjær, Lars Hamberg, Claus Heilmann-Clausen, Lars E. Kristensen, Iain Prince, and Jan A. Rasmussen. "A revised lithostratigraphy for the Palaeogene – lower Neogene of the Danish North Sea." Geological Survey of Denmark and Greenland (GEUS) Bulletin 7 (July 29, 2005): 21–24. http://dx.doi.org/10.34194/geusb.v7.4825.
Full textAbstract:
Intense drilling activity following the discovery of the Siri Field in 1995 has resulted in an improved understanding of the siliciclastic Palaeogene succession in the Danish North Sea sector (Fig. 1). Many of the new wells were drilled in the search for oil reservoirs in sand bodies of Paleocene–Eocene age. The existing lithostratigraphy was based on data from a generation of wells that were drilled with deeper stratigraphic targets, with little or no interest in the overlying Palaeogene sediments, and thus did not adequately consider the significance of the Palaeogene sandstone units in the Danish sector. In order to improve the understanding of the distribution, morphology and age of the Palaeogene sediments, in particular the economically important sandstone bodies, a detailed study of this succession in the Danish North Sea has recently been undertaken. An important aim of the project was to update the lithostratigraphic framework on the basis of the new data.The project was carried out at the Geological Survey of Denmark and Greenland (GEUS) with participants from the University of Aarhus, DONG E&P and Statoil Norway, and was supported by the Danish Energy Agency. Most scientific results cannot be released until September 2006, but a revised lithostratigraphic scheme may be published prior to that date. Formal definition of new units and revision of the lithostratigraphy are in preparation. All of the widespread Palaeogene mudstone units in the North Sea have previously been formally established in Norwegian or British wells, and no reference sections exist in the Danish sector. As the lithology of a stratigraphic unit may vary slightly from one area to another, Danish reference wells have been identified during the present project, and the lithological descriptions of the formations have been expanded to include the appearance of the units in the Danish sector. Many of the sandstone bodies recently discovered in the Danish sector have a limited spatial distribution and were sourced from other areas than their contemporaneous counterparts in the Norwegian and British sectors. These sandstone bodies are therefore defined as new lithostratigraphic units in the Danish sector, and are assigned Danish type and reference sections. There is a high degree of lithological similarity between the Palaeogene–Neogene mudstone succession from Danish offshore boreholes and that from onshore exposures and boreholes, and some of the mudstone units indeed seem identical. However, in order to acknowledge the traditional distinction between offshore and onshore stratigraphic nomenclature, the two sets of nomenclature are kept separate herein. In recent years oil companies operating in the North Sea have developed various in-house lithostratigraphic charts for the Paleocene–Eocene sand and mudstone successions in the Danish and Norwegian sectors. A number of informal lithostratigraphic units have been adopted and widely used. In the present project, these units have been formally defined and described, maintaining their original names whenever feasible, with the aim of providing an unequivocal nomenclature for the Palaeogene – lower Neogene succession in the Danish sector. It has not been the intention to establish a sequence stratigraphic model for this succession in the North Sea; the reader is referred to the comprehensive works of Michelsen (1993), Neal et al. (1994), Mudge & Bujak (1994, 1996a, b), Michelsen et al. (1995, 1998), Danielsen et al. (1997) and Rasmussen (2004).
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Baxter, M. F. W., Zulkiflie Abdullah, and M. R. Pearson. "Operational Procedures and Applications of a Wireline Formation Tester To Accurately Characterize the Gas Composition of Stacked Multiple Pools in the North Malay Basin." SPE Reservoir Evaluation & Engineering 3, no. 02 (April 1, 2000): 101–8. http://dx.doi.org/10.2118/62482-pa.
Full textAbstract:
Summary In this article we review the development of techniques to acquire reliable reservoir gas samples using a wireline formation tester in the Malaysia-Thailand Joint Development Area. This region is characterized by gas accumulations comprised of multiple stacked separate pools where reservoir conditions are often considered hostile for wireline logging operations. In the article we use data from the 16-well exploration and appraisal program, during which 1968 pre-tests and 124 samples were successfully acquired, to compare the quality of gas samples from a wireline formation tester with those obtained from drillstem tests in the same zones. Introduction Accurate knowledge of reservoir fluid composition, specifically the concentration of hydrocarbon gases and noncombustible gases such as carbon dioxide, is a key factor in the commercial assessment of upstream gas projects at the exploration and field appraisal drilling stages, and in development planning. The precise measurement of reservoir fluid composition requires the acquisition of a representative sample of formation fluid, free of drilling fluids and other contaminants. Traditionally, drill stem tests (DSTs) have offered the most reliable method by which to obtain this information. However, the cost of this method limits its application in gas accumulations comprised of multiple stacked separate pools where the individual reservoir fluid compositions need to be known well. In comparison with a DST, sampling with a wireline formation Tester results in lower total operating costs. An additional advantage lies in the fact that wireline formation testers are highly selective, allowing a series of reservoirs to be tested during a single trip into the hole. This is of particular significance in the context of Block A-18, where it would be prohibitively expensive to run DSTs on each individual hydrocarbon-bearing zone. Carigali Triton Operating Co. (CTOC) Sdn. Bhd., operator of Block A-18, JDA on behalf of its shareholders, Petronas Carigali (JDA) Sdn. Bhd., Triton Oil Co. of Thailand (JDA) Ltd., and Triton Oil Co. of Thailand Inc., is now consistently able to acquire reservoir fluid samples which are confirmed by on-site advanced chromatography, and calibrated by drill stem tests to be fully representative of in-situ native reservoir fluid compositions. This has been achieved through the use of a wireline formation tester with a pump-out capability and a downhole fluid analyzer, together with the development and implementation of key operational procedures for performing the logging operation. The study area is confined to Block A-18 of the Malaysia-Thailand Joint Development Area (MTJDA), which is geographically located offshore peninsular Malaysia and Thailand in the southern part of the Gulf of Thailand (Fig. 1). Geologically Block A-18 is located in the northern part of the Malay basin, a contiguous tertiary extensional basin system that consists of stacked multiple reservoirs (Fig. 2). Since signing of Block PSC in April 1994,1 CTOC has implemented an accelerated exploration and appraisal program. A total of 16 wells has been drilled since 1995 with a 100% success rate, resulting in the discovery of 8 fields to date. This program has made extensive use of an advanced wireline formation tester (WFT) to obtain reliable, representative reservoir fluid samples. The accuracy and reliability of the technique have been proven and refined over the 16-well program in Block A-18, where downhole conditions can be hostile, and tool operating time has exceeded 40 hours. This technique has enabled the operator to obtain specific and accurate information on the fluid composition of individual reservoirs, thereby reducing appraisal and development uncertainties in a fraction of the time that would have been needed for conventional drill stem testing and at a fraction of the cost. In this article we describe the tool used, together with the techniques that have been implemented at the wellsite to obtain representative reservoir fluid samples in an efficient and cost-effective manner. We compare the compositions of reservoir gas samples obtained with the wireline formation tester to those of samples acquired during drill stem tests (DSTs) on the same wells and reservoirs to demonstrate the accuracy and reliability of the methods employed. The success of this technique has allowed CTOC to reduce the number of DSTs required to accurately characterize the fluid composition of each reservoir. Data Acquisition Philosophy The accelerated exploration and appraisal program for Block A-18 required that an extremely thorough data acquisition philosophy be implemented. This has included seismic data acquisition [6000 line km of two dimensions (2D) and 1154 km2 of three dimensions (3D)], a total of 1,400 ft of conventional core, and over 40,000 ft of high-resolution borehole resistivity image and dipmeter logs,2 along with extensive WFT and DST programs. Implementation of the extensive WFT and DST data acquisition philosophy was also the result of several additional factors common to the North Malay basin.The geology of the area consists of multiple stacked clastic reservoirs, resulting in all fields having significant numbers of separate hydrocarbon-bearing intervals (pools) throughout the shallow, intermediate, and deep reservoirs.It was found that the concentration of hydrocarbon and nonhydrocarbon gases varies significantly with depth (Fig. 3), not only within individual fields but also between the fields (Fig. 4).The presence of abnormally high formation pressures (up to 17.5 ppg EMW) in the central part of the Block has necessitated extensive use of the wireline formation tester to facilitate the drilling operations. Varying pressure profiles are present both within individual fields and among fields (Fig. 5), which has led to complications in drilling the wells.
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Gao, Yue, Zhanli Liu, Zhuo Zhuang, Deli Gao, and Keh-Chih Hwang. "Cylindrical Borehole Failure in a Transversely Isotropic Poroelastic Medium." Journal of Applied Mechanics 84, no. 11 (September 26, 2017). http://dx.doi.org/10.1115/1.4037880.
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Rocks underground often have pores and bedding planes, which are appropriate to be described by the transversely isotropic poroelastic constitutive model. Drilling boreholes in these rocks must be careful, since stresses and pore pressure would change with time, because of the inherent time dependent property of poroelasticity as well as pore fluid diffusion. In order to correlate the behavior of transversely isotropic poroelastic model of borehole in plane strain with the behavior of isotropic poroelastic model, an equivalent isotropic material is built with carefully chosen material constants, and correlation rules are successfully developed. With the solutions for the borehole problem in an isotropic model obtained previously, the solutions to transversely isotropic model can be obtained. Two cases of tensile failure and six cases of shear failure for the borehole are considered. As a result, the allowable borehole working pressure range is formulated by explicit expressions. The failure case, time, and location could also be obtained for any given drilling pressure. Results obtained from the Hooke’s traditional elastic model are compared, and it is found that poroelastic model is necessary in borehole safety check, while Hooke’s model is not on the safe side.
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Chuan, Wu, Wen Guojun, and Han Lei. "Research on rotating speed measurement method of turbodrill based on tilt sensor." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science, July 22, 2020, 095440622094443. http://dx.doi.org/10.1177/0954406220944431.
Full textAbstract:
The rotating speed of turbodrill is a key parameter for adjusting the drilling process, which needs to be measured in real time. Based on this, a new rotating speed measurement method used in downhole turbodrill based on the tilt sensor is proposed in this paper. The basic principle is that a periodic signal will be generated by the tilt sensor along with the turbodrill, and then the rotating speed can be obtained by using fast Fourier transform to analyze the output data. Test results show that the measurement error is related to the inclination angle of the borehole, that is, this method cannot be used when the inclination angle is less than 0.4 degrees, while the measurement error is less than 3.5% when the inclination angle is more than 0.4 degrees, which meets the practical requirements. Compared with traditional methods, this method will not be interfered by mud, geological conditions and downhole vibration, and it is also a non-contact measurement method, which is very suitable for downhole environment.