Journal articles: 'Bottom-hole pressure'

1

Faizullin, Rinat, Sergey Miroshnichenko, and Ravil Sultanov. "Bottom-hole pressure optimization when operating the well lateral horizontal hole." E3S Web of Conferences 217 (2020): 03008. http://dx.doi.org/10.1051/e3sconf/202021703008.

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The problem of optimization of technological parameters as a way to improve the efficiency of oil deposit exploitation is considered in the paper. There are no standards for parameters of well bottom-hole pressure for exploitation of lateral horizontal holes. The paper presents the evaluation of optimum bottom-hole pressure at which it is advisable to exploit the deposit lateral horizontal hole with maximum “water-free” production rate. Following the calculations carried out and analysis of the graphs of additional oil and liquid production dependence on bottom-hole pressure, graphs of production dynamics and water encroachment, it was concluded that 3 groups of drilling (kickoff) of lateral holes (KLH) should be distinguished: with high forecasted starting water encroachment (>90%), average starting water encroachment (about 80%), and low starting water encroachment (about 20-50%). The distinguished 3 groups allow applying the differentiation of parameters, for which optimum bottom-hole pressure parameters for each drilling group were found.

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Astakhov, V. P., J. Frazao, and M. O. M. Osman. "On the Experimental Optimization of Tool Geometry for Uniform Pressure Distribution in Single Edge Gundrilling." Journal of Engineering for Industry 116, no. 4 (November 1, 1994): 449–56. http://dx.doi.org/10.1115/1.2902127.

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An investigation into the effect of gundrill geometry on the coolant flow, in gundrilling, is carried out. This investigation deals mainly with the loss of coolant pressure occurring in a limited space between the flank of the gundrill and the bottom of the predrilled hole. This space is named as “bottom clearance.” The pressure loss in the bottom clearance is classified into, (a) pressure loss due to flow interaction with the bottom of the drilled hole (impact pressure loss), and (b) pressure loss due to hydraulic resistance of the annular groove connecting the bottom clearance and the chip removal passage. The study indicates that a significant part of the pressure loss occurs due to flow deflection at the bottom of the hole. The reduction of pressure loss can be achieved either by reducing the coolant velocity at the orifice exit, or, by increasing the coolant pressure in the bottom clearance. In this study, the shoulder dub-off angle of the gundrill is experimentally optimized to increase the coolant pressure in the bottom clearance, thereby achieving uniform coolant pressure distribution. This uniform pressure distribution resulted in increased gundrill life without compromising the quality of the machined hole.

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Chang, Bao Hua, Jing Nan Zhang, Wei Xiong, and Shu Sheng Gao. "Elastic Exploring Law Analysis of the Deep Vuggy Reservoir." Applied Mechanics and Materials 110-116 (October 2011): 3068–73. http://dx.doi.org/10.4028/www.scientific.net/amm.110-116.3068.

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The deep cave is an important storage space in the fractured-vuggy reservoir in the Tahe oilfield, with large differences in spatial structure and the complex relationship between oil and water features, so far, mainly in elastic energy as the driving force for mining; this paper, base on the elasticity theory, analyses mining characteristics of the three fractured-vuggy model, and found that the bottom hole pressure has a certain relationship with the fracture and cave properties, the bottom hole pressure equation was established, and verified the bottom hole pressure variation of three fractured-vuggy mode by physical simulation, and analyzed the relationship between cumulative production and accumulation of pressure drop curves, the results showed that: showed a single index of changes in bottom hole pressure for the single cave mode and single-fractured-cave mode, and the cumulative production and cumulative pressure drop curve is linear, the bottom hole pressure showed double-index change for the cave-fractured-cave model, and the cumulative production and accumulation of pressure drop curves have a bend segment, this research provide a basis for the development in the deep vuggy reservoir .

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Awadalla, Medhat, and Hassan Yousef. "Neural Networks for Flow Bottom Hole Pressure Prediction." International Journal of Electrical and Computer Engineering (IJECE) 6, no. 4 (August 1, 2016): 1839. http://dx.doi.org/10.11591/ijece.v6i4.10774.

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Installation of down-hole gauges in oil wells to determine Flowing Bottom-Hole Pressure (FBHP) is a dominant process especially in wells lifted with electrical submersible pumps. However, intervening a well occasionally is an exhaustive task, associated with production risk, and interruption. The previous empirical correlations and mechanistic models failed to provide a satisfactory and reliable tool for estimating pressure drop in multiphase flowing wells. This paper aims to find the optimum parameters of Feed-Forward Neural Network (FFNN) with back-propagation algorithm to predict the flowing bottom-hole pressure in vertical oil wells. The developed neural network models rely on a large amount of available historical data measured from actual different oil fields. The unsurpassed number of neural network layers, the number of neurons per layer, and the number of trained samples required to get an outstanding performance have been obtained. Intensive experiments have been conducted and for the sake of qualitative comparison, Radial Basis neural and network and the empirical modes have been developed. The paper showed that the accuracy of FBHP estimation using FFNN with two hidden layer model is better than FFNN with single hidden layer model, Radial Basis neural network, and the empirical model in terms of data set used, mean square error, and the correlation coefficient error. With best results of 1.4 root mean square error (RMSE), 1.4 standard deviation of relative error (STD), correlation coefficient (R) 1.0 and 99.4% of the test data sets achieved less than 5% error. The minimum sufficient number of data sets used in training ANN model can be low as 12.5% of the total data sets to give 3.4 RMSE and 97% of the test data achieved 90% accuracy.

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Awadalla, Medhat, and Hassan Yousef. "Neural Networks for Flow Bottom Hole Pressure Prediction." International Journal of Electrical and Computer Engineering (IJECE) 6, no. 4 (August 1, 2016): 1839. http://dx.doi.org/10.11591/ijece.v6i4.pp1839-1856.

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Installation of down-hole gauges in oil wells to determine Flowing Bottom-Hole Pressure (FBHP) is a dominant process especially in wells lifted with electrical submersible pumps. However, intervening a well occasionally is an exhaustive task, associated with production risk, and interruption. The previous empirical correlations and mechanistic models failed to provide a satisfactory and reliable tool for estimating pressure drop in multiphase flowing wells. This paper aims to find the optimum parameters of Feed-Forward Neural Network (FFNN) with back-propagation algorithm to predict the flowing bottom-hole pressure in vertical oil wells. The developed neural network models rely on a large amount of available historical data measured from actual different oil fields. The unsurpassed number of neural network layers, the number of neurons per layer, and the number of trained samples required to get an outstanding performance have been obtained. Intensive experiments have been conducted and for the sake of qualitative comparison, Radial Basis neural and network and the empirical modes have been developed. The paper showed that the accuracy of FBHP estimation using FFNN with two hidden layer model is better than FFNN with single hidden layer model, Radial Basis neural network, and the empirical model in terms of data set used, mean square error, and the correlation coefficient error. With best results of 1.4 root mean square error (RMSE), 1.4 standard deviation of relative error (STD), correlation coefficient (R) 1.0 and 99.4% of the test data sets achieved less than 5% error. The minimum sufficient number of data sets used in training ANN model can be low as 12.5% of the total data sets to give 3.4 RMSE and 97% of the test data achieved 90% accuracy.

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Zhang, Yichi, Jin Yang, Wei Liu, Mu Li, Zhenxiang Zhang, and Xin Zhao. "Bottom Hole Pressure Calculation of Fractured Carbonate Formation." IOP Conference Series: Earth and Environmental Science 570 (November 12, 2020): 022018. http://dx.doi.org/10.1088/1755-1315/570/2/022018.

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7

Svalov, A. M. "Bottom-hole filtration at a positive differential pressure." Soviet Mining Science 25, no. 1 (January 1989): 56–60. http://dx.doi.org/10.1007/bf02528431.

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Zhao, Heqian, Huaizhong Shi, Zhongwei Huang, Zhenliang Chen, Ziang Gu, and Fei Gao. "Mechanism of Cuttings Removing at the Bottom Hole by Pulsed Jet." Energies 15, no. 9 (May 3, 2022): 3329. http://dx.doi.org/10.3390/en15093329.

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Vibration drilling technology induced by hydraulic pulse can assist the bit in breaking rock at deep formation. Simultaneously, the pulsed jet generated by the hydraulic pulse promotes removal of the cuttings from the bottom hole. Nowadays, the cuttings removal mechanism of the pulsed jet is not clear, which causes cuttings to accumulate at the bottom hole and increases the risk of repeated cutting. In this paper, a pressure-flow rate fluctuation model is established to analyze the fluctuation characteristics of the pulsed jet at the bottom hole. Based on the model, the effects of displacement, well depth, drilling fluid viscosity, and flow area of the pulsed jet tool on the feature of instantaneous flow at the bottom hole are discussed. The results show that the pulsed jet causes flow rate and pressure to fluctuate at the bottom hole. When the displacement changes from 20 L/s to 40 L/s in a 2000 m well, the pulsed jet generates a flow rate fluctuation of 4–9 L/s and pressure fluctuation of 0.1–0.5 MPa at the bottom hole. With the flow area of the tool increasing from 2 cm2 to 4 cm2, the amplitude of flow rate fluctuation decreases by 72.5%, and the amplitude of pressure fluctuation decreases by more than 60%. Combined with the fluctuation feature of the flow field and the water jet attenuation law at the bottom hole, the force acting on the cuttings under the pulsed jet is derived. It is found that flow rate fluctuation improves the mechanical state of cuttings and is beneficial for cuttings tumbled off the bottom hole. This research provides theoretical guidance for pulsed jet cuttings cleaning at the bottom hole.

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Xiong, Ping, Wang-shui Hu, Hai-xia Hu, and Hailong Liu. "Mechanism of shear failure near fracture face during drainage process of CBM well." Journal of Petroleum Exploration and Production Technology 10, no. 8 (April 27, 2018): 3309–17. http://dx.doi.org/10.1007/s13202-018-0467-y.

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Abstract In this paper, whether the coal fines can be induced by shear failure during drainage process has been discussed in detail. By coupling with the percolation theory, the elasticity mechanics were used to construe the extra stresses in the formation surrounding with the hydraulic fracture. The safe window of the bottom hole pressure was also calculated from the failure envelope. The research shows that the formation pressure on the fracture surface of the coal seam is negatively related with the bottom hole pressure, and the induced stress is positively related with the bottom hole pressure during the drainage process of fractured CBM wells. The pore pressure around the fracture changed due to pore-elastic effects, which also caused a significant change of the in situ stresses. In order to avoid the breakout of the coal seam around hydraulic fracture during drainage process, the model of the reasonable bottom hole pressure is also built.

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Wang, Xiaoming, Junbin Chen, Dazhong Ren, and Zhaolong Shi. "Role of Gas Viscosity for Shale Gas Percolation." Geofluids 2020 (September 30, 2020): 1–10. http://dx.doi.org/10.1155/2020/8892461.

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Viscosity is an important index to evaluate gas flowability. In this paper, a double-porosity model considering the effect of pressure on gas viscosity was established to study shale gas percolation through reservoir pressure, gas velocity, and bottom hole flowing pressure. The experimental results show that when pressure affects gas viscosity, shale gas viscosity decreases, which increases the percolation velocity and pressure drop velocity of the free state shale gas in matrix and fracture systems. And it is conducive to the desorption of adsorbed shale gas and effectively supplemented the bottom hole flowing pressure with the pressure wave propagation range and velocity increasing, so that the rate of pressure drop at the bottom of the well slows down, which makes the time that bottom hole flowing pressure reaches stability shortened. Therefore, the gas viscosity should be fully considered when studying the reservoir gas percolation.

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11

Shete, Hanmant V., and Madhav S. Sohani. "Effect of Process Parameters on Hole Diameter Accuracy in High Pressure Through Coolant Peck Drilling Using Taguchi Technique." International Journal of Materials Forming and Machining Processes 5, no. 1 (January 2018): 12–31. http://dx.doi.org/10.4018/ijmfmp.2018010102.

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Machining with pressurized coolant is nowadays widely accepted technique in the manufacturing industry, especially in high performance machining conditions. The data on the effects of variation of high coolant pressure in drilling operation is limited. This paper presents the effect of high coolant pressures along with spindle speed, feed rate and peck depth on hole diameter accuracy. Experiments were performed on EN9 steel with TiAIN coated through coolant drill on CNC vertical machining center. Taguchi technique was employed for design of experiments and analysis of results. Results showed that the higher values of optimal coolant pressure and spindle speed were demanded for drilling at bottom of hole as compared to that for drilling at top of hole. The optimal values of feed rate and peck depth were same for both the cases of drilling at top and bottom of hole. Use of high coolant pressure in drilling permits higher peck depth for better hole diameter control which results in reduced cycle time and hence production cost.

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12

Liu, Jia, Yinghong Liu, Ruyong Feng, and Na Li. "Method and Application of Reducing Pressure and Increasing Production in Nanometer Porous Coal Seam." Tobacco Regulatory Science 7, no. 5 (September 30, 2021): 4608–20. http://dx.doi.org/10.18001/trs.7.5.2.27.

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Objectives: In order to deeply analyze the feasibility of reducing pressure and increasing production of coalbed methane wells in nano-porous coal seams and clarify the principle of well selection. Methods: The sensitivity of bottom hole flowing pressure to coalbed methane production is analyzed by establishing productivity equation in stable production period of coalbed methane wells. Combined with the numerical simulation method, the drainage and production effect of L-1 well in the Block A is simulated after reducing the flowing pressure at the bottom of the well. Results: The results show that for CBM wells that have been put into production, the effect of increasing the production can be achieved by reducing the bottom hole flowing pressure, and when the bottom hole flowing pressure is large, reducing the bottom hole flowing pressure can obtain a larger increase in gas production. The cumulative gas production of Well L-1 can be increased by 110x104m3 compared with the previous measures, and the increase rate can reach 85%. Conclusion: Combining with the pressure-reducing and increasing production wells in the Block A, the applicable conditions for pressure-dropping and increasing production to increase the production of CBM wells are proposed, that is, continuous and stable drainage and production, and there is a certain height of liquid column between the moving liquid level and the coal roof before operation.

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Zhang, Ruiyao, Jun Li, Gonghui Liu, Hongwei Yang, and Hailong Jiang. "Analysis of Coupled Wellbore Temperature and Pressure Calculation Model and Influence Factors under Multi-Pressure System in Deep-Water Drilling." Energies 12, no. 18 (September 14, 2019): 3533. http://dx.doi.org/10.3390/en12183533.

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The purpose of this paper is to discuss the variation of wellbore temperature and bottom-hole pressure with key factors in the case of coupled temperature and pressure under multi-pressure system during deep-water drilling circulation. According to the law of energy conservation and momentum equation, the coupled temperature and pressure calculation model under multi-pressure system is developed by using the comprehensive convective heat transfer coefficient. The model is discretized and solved by finite difference method and Gauss Seidel iteration respectively. Then the calculation results of this paper are compared and verified with previous research models and field measured data. The results show that when the multi-pressure system is located in the middle formation, the temperature of the annulus corresponding to location of the system is the most affected, and the temperature of the other areas in annulus is hardly affected. However, when the multi-pressure system is located at the bottom hole, the annulus temperature is greatly affected from bottom hole to mudline. In addition, the thermo-physical parameters of the drilling fluid can be changed by overflow and leakage. When only overflow occurs, the annulus temperature increases the most, but the viscosity decreases the most. When only leakage occurs, the annulus temperature decreases the most and the viscosity increases the most. However, when the overflow rate is greater than the leakage rate, the mud density and bottom-hole pressure increase the most, and both increase the least when only leakage occurs. Meanwhile, bottom-hole pressure increases with the increase of pump rate but decreases with the increase of inlet temperature. The research results can provide theoretical guidance for safe drilling in complex formations such as multi-pressure systems.

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Ni, Hong Jian, Rui He Wang, Wei Qiang Song, and Hui Fang Song. "A Study on the Mechanism of Bottom Hole Hydraulic Pulse Increasing Drilling Rate." Advanced Materials Research 354-355 (October 2011): 621–26. http://dx.doi.org/10.4028/www.scientific.net/amr.354-355.621.

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Practically, the distribution and variation of the bottom-hole hydraulic energy has significant influence on drilling rate, and it’s helpful to induce bottom-hole hydraulic pulse to improve the rock breaking and drilling efficiency. The analysis of bottom-hole rock stress condition and cuttings start-up mechanism indicates that, bottom-hole hydraulic pulsation can decrease the bottom hole pressure, reduce the fracture strength of rock, and strengthen bottom-hole purification, thus improve the efficiency of rock breaking and drilling. The higher the pulsation value is, the more effective of the acceleration of the drilling rate, while well depth increases, the acceleration effect diminishes gradually. Simulation of jet flow field drilled by 3-nozzle 3-cone bit, combined with field application, verify the mechanism that bottom-hole hydraulic pulsation could improve ROP. The result of the study provides a basis for the development of practical technology.

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15

Awadalla, M., H. Yousef, A. Al-Shidani, and A. Al-Hinai. "Artificial Intelligent techniques for Flow Bottom Hole Pressure Prediction." INTERNATIONAL JOURNAL OF COMPUTERS & TECHNOLOGY 15, no. 12 (September 23, 2016): 7263–83. http://dx.doi.org/10.24297/ijct.v15i12.4354.

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This paper proposes Radial Basis and Feed-forward Neural Networks to predict the flowing bottom-hole pressure in vertical oil wells. The developed neural network models rely on a large amount of available historical data measured from actual different oil fields. The unsurpassed number of neural network layers, the number of neurons per layer, and the number of trained samples required to get an outstanding performance have been obtained. Intensive experiments have been conducted and the standard statistical analysis has beenÂ accomplished on the achieved results to validate the modelsâ€™ prediction accuracy. For the sake of qualitative comparison, empirical modes have been developed. The obtained results show that the proposed Feed-Forward Neural Network models outperforms and capable of estimating the FBHPaccurately.The paper showed that the accuracy of FBHP estimation using FFNN with two hidden layer model is better than FFNN with single hidden layer model, Radial Basis neural network, and the empirical model in terms of data set used, mean square error, and the correlation coefficient error. With best results of 1.4 root mean square error (RMSE), 1.4 standard deviation of relative error (STD), correlation coefficient (R) 1.0 and 99.4% of the test data sets achieved less than 5% error. The minimum sufficient number of data sets used in training ANN model can be low as 375 sets only to give a 3.4Â RMES and 97% of the test data achieved 90% accuracy.

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Sun, Xiao Feng, Jun Bo Qu, Tie Yan, and Li Wang. "Numerical Simulation for Gas-Liquid Two-Phase Flow along the Borehole after Air Cutting." Advanced Materials Research 821-822 (September 2013): 1414–17. http://dx.doi.org/10.4028/www.scientific.net/amr.821-822.1414.

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When gas kick Occurs during drilling, because of pressure, temperature, coefficient of gas compressibility and other parameters changing continuously, gas will slip along the borehole and also accompany expansion some extent, and bottom hole differential pressure increases, resulting in the amount of invasion gas increasing continuously until blowout. The procedure of gas kick till blowout in the borehole is transient gas-liquid two-phase flow, studying on The development of gas-liquid two-phase flow parameters variation characteristics and bottom hole pressure variation characteristics plays an significant role to understand blowout occurrence and development characteristics. This paper using methane-mud as the circulating medium simulates the procedure of gas kick till blowout near the bottom under the condition which is almost the onsite drilling process, Analyzing the flow pattern, bottom hole pressure variation characteristics, and velocity distribution under the different stages of gas kick, different influx, and obtained an initial understanding.

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Xiao, Ding Jun, Bin Li, Chuan Jin Pu, and Hui Qi Zhou. "Model Test and Numerical Simulation for Directional Pressure Relief Blasting." Advanced Materials Research 779-780 (September 2013): 848–56. http://dx.doi.org/10.4028/www.scientific.net/amr.779-780.848.

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To study directional pressure relief blasting, cement mortar model tests are carried out. Protecting borehole wall, free-face wall and bottom wall are tested of the dynamic strain. Three-dimensional numerical simulation and numerical calculation of the tests are conducted by using LS-DYNA3D. The pressure values and test results of the protecting borehole wall, free-face wall and bottom wall with the same distance from the explosives are compared. Development and distribution of pressure regularity are analyzed; blast hole pressure relief effect of protecting borehole wall materials and bottom interval air column are explicated. The present results indicate that there is an obvious stress concentration phenomenon on the free-face wall, with an average pressure decrease rate of 26% from the free-face wall to the protecting borehole wall with the same distance to the explosive center, while the isolation materialPVCU plays a good directional protection. The pressure effect of the blast hole bottom air column on the blast hole is apparent. The simulation results are consistent with the experimental dates.

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Liu, Mingze, Bing Bai, and Xiaochun Li. "A Unified Formula for Determination of Wellhead Pressure and Bottom-hole Pressure." Energy Procedia 37 (2013): 3291–98. http://dx.doi.org/10.1016/j.egypro.2013.06.217.

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Shi, Jun Tai, Xiang Fang Li, Lei Zhang, Wei Na Ren, Le Zhong Li, and Hui Du. "The Detectable Radius of an Oil Well Considering Pressure Gauge Resolution Ratio." Advanced Materials Research 560-561 (August 2012): 1188–94. http://dx.doi.org/10.4028/www.scientific.net/amr.560-561.1188.

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For a case of constant-rate liquid production from a single well centered in a horizontal, homogeneous-acting, isopachous, and infinite reservoir, based on fundamentals of fluid flow in porous media the bottom hole flowing pressure never stabilize. In the process of field well testing, however, pressure values measured by the pressure gauge which has a definite resolution value will not change after a period, so the bottom hole flowing pressure can be considered to be stabilized. According to this situation, through theoretical derivation, a stabilized time formula is firstly proposed, by which the time after which the bottom hole flowing pressure measured with a pressure gauge will be stabilized can be calculated, and the stabilized time for a given pressure gauge is in direct proportion to the liquid producing rate, but in inverse proportion to the resolution ratio of the pressure gauge. Applied the stabilized time formula, a new formula of detectable radius can be derived, by which the effect of resolution of the pressure gauge can be considered. Secondly, the time after which the value of the pressure gauge measured in the bottom hole of the observation well starts to change during interference testing is obtained, and the time is related to the fluid flow rate and the distance between the producing well and the observation well. The conclusion can be applied as a reference in the design process of working system during well testing.

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Liu, Xinfu, Chunhua Liu, and Jianjun Wu. "A Modern Approach to Analyzing the Flowing Pressures of a Two-Phase CBM and Water Column in Producing Wellbores." Geofluids 2019 (May 7, 2019): 1–9. http://dx.doi.org/10.1155/2019/3093707.

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A modern methodology is presented for the system analysis of flowing pressures in order to forecast the dynamic behavior and solve the forthcoming problems that emerge in two-phase coalbed methane (CBM) wellbores. The proposed methodology involves a numerical integration technique to calculate flowing pressures and pressure drops of CBM and water flow from the bottom hole to the well head. The methodology is validated against full-scale measured data in coalfields. The relationships developed match CBM reservoir behavior and wellbore conditions along the annulus with an overall accuracy of 1.13%. The computation of flowing pressures involves a liquid holdup and kinetic energy term with flow rate increments, a compressibility factor with depth increments, and a friction factor with Reynolds number. The flowing pressures of a two-phase column fully reflect the dynamic flowing performance due to the combined action of the water level, CBM, and water flow rates. The effect of CBM and water column pressures is more obvious than that of CBM column pressures. The pressure ratios of CBM and the water column to the bottom hole decline rapidly with the increase of the dynamic water level. CBM and water flow rates can be improved with increases in CBM and water column pressure for two-phase producing wellbores. The decrease of flowing pressures and increased increment of the pressure drop for the two-phase column are beneficial to CBM desorption and result in the increased CBM and water production. It will control the falling speed of the dynamic water level above CBM and the water column and enhance CBM reservoir productivity. The increases of CBM and water column pressure from 34.6 kPa to 922 kPa and the decreases of pressure in the bottom hole from 2.252 MPa to 1.328 MPa lead to the increases of the CBM flow rate from 3327 m3/d to 6721 m3/d.

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Malich, Mykola, Volodymyr Katan, Dmytro Vasyliev, and Ihor Chuhunkov. "Method of calculating the parameters of the mountain pressure epure." E3S Web of Conferences 109 (2019): 00055. http://dx.doi.org/10.1051/e3sconf/201910900055.

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Elevated bearing load pressure is formed near the exposed part of the coal seam, compared with static stresses normal to the reservoir. The loading of the near-bottom part of the coal seam is formed by linearly damped, according to the principle of Saint-Venant, from the bottom of the face to the massif of the tangential stresses from contact friction between the formation and lateral enclosing rocks in the form of a reference rock pressure, the epure of which is described by a convex quadratic function whose initial value is normal stress at the top of the bottom hole fracture, and the final stress is to the rock pressure in the zone of the intact massif. In connection with the above scientific position, a method has been developed for determining the vertical normal stress at the top of the bottom hole fracture, the length of the epure, and the distance from the bottom to the maximum of the reference pressure.

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Shihui, Sun, Yan Tie, Bi Xueliang, Chen Xun, and Zhang Nan. "Wellbore Flow Analysis of a Gas-Kick Well During Shut-In." Open Fuels & Energy Science Journal 8, no. 1 (March 31, 2015): 63–67. http://dx.doi.org/10.2174/1876973x01508010063.

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Due to the effects of wellbore storage, shut-in period allows additional inflow of gas bubbles into the annulus. Wellbore and casing pressures rise during shut-in of a gas kick as a consequence of gas upward migration and gas compressibility, which will threaten the safety of well control. Therefore, the variation law of surface and wellbore pressures for a gas kick well during shut-in should be investigated. Based on wellbore storage effect, a new model to the wellbore and casing pressure build-up during shut-in for a gas kick well is developed in this paper. Simulation results show that at different gas kick volumes, the rate of bottom-hole pressure rise increases as the permeability decreases. And surface casing pressure stabilizes quickly for low permeable formations. However, at equal initial annular gaseous volume, the rates of rise of the bottom-hole and surface casing pressures for low permeable formations are slower than for high permeability formations.

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Korganov, I. I., and A. Kh Mirzajanzade. "The relationship between filtration of liquid from the reservoir into the well and infiltration into the reservoir." Scientific Petroleum, no. 2 (December 30, 2021): 33–38. http://dx.doi.org/10.53404/sci.petro.0210200013.

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The article is devoted to determining the laws that govern the movement of fluid from the well into the reservoir and back. To study this pattern, the authors conducted experiments on a circular model. Based on the analysis of the experimental results, the following pattern was revealed: when a certain amount of liquid is injected into the reservoir, significantly less repression is required than depression is required when the same amount of liquid is taken from the reservoir. From what has been said, it can be concluded that the pick-up coefficient in all cases is significantly higher than the productivity coefficient. In addition, a certain pattern has been revealed between reservoir pressure and pressure gradients in the bottom-hole zone of the formation. This pattern also lies in the fact that the lower the reservoir pressure, the greater part of the total depression falls on the bottom-hole zone of the formation. This suggests that outside the bottom-hole zone of the formation (critical zone) at low pressure, the value of pressure gradients is insignificant. Therefore, a significant part of the pressure gradients falls on the critical zone. Of course, the work done does not pretend to be a complete study, but it nevertheless shows that the influence of local resistances must also be taken into account in hydrodynamic calculations. Keywords: Fluid movement; Filtration from the formation into the well; Infiltration into the formation; Bottom-hole zone of the formation; Critical zone; Modeling.

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Li, Zhiyuan, Naira Hovakimyan, and Glenn-Ole Kaasa. "Bottom hole pressure estimation and ℒ1 adaptive control in managed pressure drilling system." International Journal of Adaptive Control and Signal Processing 31, no. 4 (February 17, 2016): 545–61. http://dx.doi.org/10.1002/acs.2672.

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Adiyat, Muhammad Faza. "Desain Constant Bottom Hole Pressure Managed Pressure Drilling Lubang 12.25” Sumur Eksplorasi “X”." Majalah Ilmiah Swara Patra 11, no. 2 (September 30, 2021): 5–16. http://dx.doi.org/10.37525/sp/2021-2/283.

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Guan, Feng, Weiguo Ma, Yiliu Tu, Chuanxi Zhou, Ding Feng, and Bo Zhou. "An Experimental Study of Flow Behavior of Coiled Tubing Drilling System." Advances in Mechanical Engineering 6 (January 1, 2014): 935159. http://dx.doi.org/10.1155/2014/935159.

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Coiled tubing drilling has become an important development direction of drilling. The method of combining theoretical calculation with the experimental verification is adopted to analyze the flow of the coiled tubing drilling system. A set of experimental bench is developed, three kinds of curvature ratio of coiled tubing are used, and the frictional pressure losses of coiled tubing and partial pressure drop of each downhole tool are tested. The results of experiments with water agree well with rough pipe calculation model. The pressure losses of coiled tube are obviously larger than that of straight tube, and the value of it is about 11–17%. The larger the curvature ratio is, the more the pressure losses of coiled tubing are. The fluid experiment with the polymer presents obviously the drag reduction effect. Experiment of simulated bottom hole assembly shows that partial pressure drop of bottom hole assembly is large. It has a little effect on the pressure losses of coiled tubing when whole bottom hole assemblies are connected. The research results can be used as the basis for formulating coiled tubing drilling process parameters, which will provide a guide for engineering practice.

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Yi, Xian Zhong, Song Lin Yi, Hui Shu, Yuan Qiang Ji, and Sheng Zong Jiang. "Hydromechanics Analysis with Flow-Field Characteristics of High Pressure Water-Jet in Sloping Bottom Hole of Radial Horizontal Drilling." Advanced Materials Research 952 (May 2014): 190–93. http://dx.doi.org/10.4028/www.scientific.net/amr.952.190.

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According to the principle of fluid dynamics, the Fluent software is used for the numerical simulation analysis of three-dimensional single-hole nozzle submerged jet flow field of radial drilling inclined shaft. The results show that when the bottom is tilted, there are two sizes of spiral along the center axis, and the vortices along tilt direction of the wall are stronger. When the jet source closes the bottom, the kinetic energy of jet is converted into the impact for the bottom of well, making the pressure of bottom hole on the wall have a tendency to rise.

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Liu, Xinfu, Chunhua Liu, and Guoqiang Liu. "Dynamic behavior of coalbed methane flow along the annulus of single-phase production." International Journal of Coal Science & Technology 6, no. 4 (October 15, 2019): 547–55. http://dx.doi.org/10.1007/s40789-019-00276-1.

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Abstract Dynamic behavior of coalbed methane (CBM) flow will provide the theoretical basis to optimize production performance for a given well. A mathematical model is developed to simulate flowing pressures and pressure drops of CBM column from well head to bottom hole. The measured parameters and independent variables of flow rates, flowing pressures and temperatures are involved in CBM producing process along the annulus. The developed relationships are validated against full-scale measured data in single-phase CBM wellbores. The proposed methodology can analyze the dynamic behavior in CBM reservoir and process of CBM flow with an overall accuracy of 2%. The calculating process of flowing pressures involves friction factor with variable Reynolds number and CBM temperature and compressibility factor with gravitational gradients. The results showed that the effect of flowing pressure on CBM column was more obvious than that on CBM and water column accompanied by an increase of dynamic water level. The ratios of flowing pressure on increment of CBM column to the whole column increased with the declined flow rates of water column. Bottom-hole pressure declined with the decreased flowing pressure of CBM column along the annulus. It will lead to the results of the increased pressure drop of CBM column and CBM flow rate in single-phase CBM wellbores.

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29

Wang, Xiaoming, Junbin Chen, Jianhong Zhu, and Diguang Gong. "Effect of the Angle between Hydraulic Fracture and Natural Fracture on Shale Gas Seepage." Mathematical Problems in Engineering 2020 (December 23, 2020): 1–13. http://dx.doi.org/10.1155/2020/5136948.

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Fracturing technology is an effective measure to exploit shale gas and the fractures improve the seepage ability of shale reservoir after fracturing. In this paper, taking Chang 7 of Yanchang Formation as the study area, a double porosity seepage model considering natural fracture was established and it was solved by finite element method of COMSOL5.5; then, shale gas seepage was analyzed under different angles between hydraulic fracture and natural fracture finally. Meanwhile, angles between hydraulic fracture and natural fracture were optimized by analyzing both the reservoir pressure distribution and bottom hole flowing pressure. Also, a permeability experiment with liquid was conducted to verify the accuracy of the numerical simulation result. Both numerical simulation and permeability measurement experiment get a uniform result that the optimal angle between hydraulic fracture and natural fracture is 90°. Permeability is the highest, shale gas seepage rate is the fastest, bottom hole flowing pressure is the highest, and also it is beneficial to the desorption of adsorbed gas in the matrix system and then effectively supplements reservoir pressure and bottom hole flowing pressure. The research results will provide some theoretical guidance for fracturing design.

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30

Zhao, Yu, Kao Ping Song, and Yin Feng Liu. "Experimental Study on Fluid-Solid Coupling Seepage Flow in Putaohua Reservoir." Advanced Materials Research 594-597 (November 2012): 2602–6. http://dx.doi.org/10.4028/www.scientific.net/amr.594-597.2602.

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According to existing fluid-solid coupling models, reasonable range and control technology of pressure depression cone has not be formed in Putaohua reservoir. In this paper, using laboratory experiment, the relationship between rock elastic-plastic deformation, single phase permeability of oil or water and relative permeability curves has been measured and the following important facts has been established: oil well bottom hole pressure which is lower than formation pressure is in a reasonable range during the initial stage of commissioning, and a gently pressure depression cone is formed between the formation and wellbore, that can reduce the permeability loss by compaction settlement and particle migration and return to production in reasonable bottom hole pressure while the water flooding takes effect and thus enhance the oil recovery.

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31

陶, 瑞东. "Analyzing the Effect of Gas Layer Thickness on Bottom Hole Pressure." Journal of Oil and Gas Technology 38, no. 02 (2016): 59–65. http://dx.doi.org/10.12677/jogt.2016.382016.

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32

Hailong, Liu. "Analysis of Factors Affecting Bottom Hole Pressure in Tight Gas Reservoir." International Journal of Oil, Gas and Coal Engineering 7, no. 6 (2019): 118. http://dx.doi.org/10.11648/j.ogce.20190706.12.

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33

Zhou, Jing. "Adaptive PI Control of Bottom Hole Pressure during Oil Well Drilling." IFAC-PapersOnLine 51, no. 4 (2018): 166–71. http://dx.doi.org/10.1016/j.ifacol.2018.06.060.

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34

Ki, Seil, Ilsik Jang, Booho Cha, Jeonggyu Seo, and Oukwang Kwon. "Restoration of Missing Pressures in a Gas Well Using Recurrent Neural Networks with Long Short-Term Memory Cells." Energies 13, no. 18 (September 9, 2020): 4696. http://dx.doi.org/10.3390/en13184696.

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This study proposes a data-driven method based on recurrent neural networks (RNNs) with long short-term memory (LSTM) cells for restoring missing pressure data from a gas production well. Pressure data recorded by gauges installed at the bottom hole and wellhead of a production well often contain abnormal or missing values as a result of gauge malfunctions, noise, outliers, and operational instability. RNNs employing LSTM cells to prevent long-term memory loss have been widely used to predict time series data. In this study, an RNN with the LSTM method was used to restore abnormal or missing wellhead and bottom-hole pressures in three intervals within a production sequence of more than eight years in duration. The pressure restoration was performed using various input features for RNNs with LSTM models based on the characteristics of the available data. It was carried out through three sequential processes and the results were acceptable with a mean absolute percentage error no more than 5.18%. The reliability of the proposed method was verified through a comparison with the results of a physical model.

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35

Zhang, Guo Cheng, Yang Liu, and Zhao Hui Zhang. "Study on the Optimal Design Methodology of Fracture Spacing in Low-Permeability Reservoir Horizontal Well." Advanced Materials Research 868 (December 2013): 487–96. http://dx.doi.org/10.4028/www.scientific.net/amr.868.487.

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Threshold pressure gradient for extra-low permeability reservoir is studied experimentally. A production model is established which couples wellbore pipe flow, fracture linear flow and reservoir non-Darcy flow. The influence of bottom-hole pressure and reservoir permeability on threshold distance is performed based on the model. A fracture spacing design method is provided for different bottom-hole pressure and reservoir permeability. Results show that threshold pressure gradient increases considerably as permeability decreases when permeability is below 0.02 mD; threshold pressure gradient is relatively lower when permeability is greater than 0.1 mD; threshold pressure gradient decreases gradually and flattens when permeability lies between 0.02 mD and 0.1 mD. Simulated threshold pressure gradient of formation water is as one-third as that of crude oil. While permeability is between 0.01-0.05 mD, 0.05-0.1 mD, 0.1-0.5 mD and 0.5-1.0 mD, the optimal fracture spacing is about 9 m, 16 m; 36 m and 50 m.

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36

Astakhov, V. P., S. Abi Karam, and M. O. M. Osman. "The Correlation Between the Cutting Fluid Pressure Distribution and the Topography of Tool Wear in BTA Drilling." Journal of Manufacturing Science and Engineering 120, no. 4 (November 1, 1998): 820–22. http://dx.doi.org/10.1115/1.2830226.

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This paper investigates experimentally the correlation between the cutting fluid pressure distribution in the bottom clearance (the space enclosed by the bottom of the hole being drilled from one side and the flanks of the drill head from the other) and the flank wear of BTA drills. Two types of BTA drills were studied representing two basic drill designs in the current use: single- and multi-edge drilling heads. Experiments included the study of the bottom clearance topology, the measurements of the cutting fluid pressure distribution in the bottom clearance, and the study of the tool wear topology. The results reveal the notable correlation between the cutting fluid pressure distribution in the bottom clearance and the topography of tool wear.

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37

Bøggild, Carl Egede, Ole B. Olesen, P. Ahlstrøm Andreas, and Peer Jørgensen. "Automatic glacier ablation measurements using pressure transducers." Journal of Glaciology 50, no. 169 (2004): 303–4. http://dx.doi.org/10.3189/172756504781830097.

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AbstractAn instrument is described that automatically records ice ablation while eliminating the need for ablation stakes. A pressure transducer placed at the bottom of a hole drilled into the ice is connected by a hose to a bladder lying on the surface. Ice ablation is detected as a reduction in the hydrostatic pressure measured by the transducer.

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38

Zhu, Ge, and Shimin Dong. "Simulation Model of Bottom Hole Dynamic Pressure and Reservoir Dynamic Stress in Hydraulic Fracturing with Pulse Injection." Mathematical Problems in Engineering 2020 (October 19, 2020): 1–13. http://dx.doi.org/10.1155/2020/2906973.

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To study the mechanism of hydraulic fracturing with pulse injection theoretically, in this paper, the transient flow model of fracturing fluid in the pipe string was established, and it was solved by method of characteristics and finite difference method, respectively. Furthermore, the elastodynamic model of reservoir was also established. Based on the finite element method, the dynamic stress distribution in the reservoir was simulated and calculated. In addition, the influence of parameters in the pulse injection scheme on dynamic stress was analyzed. The results indicate that the unsteady injection produces a pulse pressure wave at the wellhead. The pressure wave propagates along the pipe string to the bottom of the well, and its amplitude attenuates due to the resistance loss. When the pressure wave propagates to the bottom of the well, it will be reflected and there is a superposition area of the downward pressure wave and upward reflection wave near the bottom hole. The bottom hole pressure of pulse injection is the sum of stable injection pressure and the above pressure wave. Simultaneously, this fluid pressure with pulse variation will stimulate reservoir to produce dynamic stress in its interior. The pulse adjustment time and adjustment amplitude in the injection scheme have a significant impact on the dynamic stress. The results of this paper are helpful to understand the mechanism of hydraulic fracturing with pulse fluid injection and provide guidance for its parameter design.

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39

Naghiyev, Faig Bakhman Ogli. "Amplitude-Frequency Characteristics of the Oscillations of Methane Gas Bubbles in Oil." International Journal of Chemoinformatics and Chemical Engineering 7, no. 2 (July 2018): 16–28. http://dx.doi.org/10.4018/ijcce.2018070102.

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The author presents an analytical solution to the problem of acoustic-wave-induced oscillations of methane gas bubbles in an oil reservoir at bottom-hole conditions. The amplitude-frequency characteristics are computed for realistic reservoir temperature, pressure, and dissolved gas parameters that make the oil compressibility, density, and viscosity quite different from those of the degassed oil at surface conditions. The author compares the damping decrement of these ultrasonic oscillations to those at normal atmospheric-pressure surface conditions. The solution allowed the author to estimate the ultrasonic vibration frequency range that is optimal and most effective for improving the flow characteristics in a producing reservoir in the near-well zone at a realistic bottom-hole regime.

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40

He, Zhang, and Tan Yun. "Implement intelligent dynamic analysis of bottom-hole pressure with naive Bayesian models." Multimedia Tools and Applications 78, no. 21 (July 15, 2018): 29805–21. http://dx.doi.org/10.1007/s11042-018-6340-7.

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41

Nait Amar, Menad, Nourddine Zeraibi, and Kheireddine Redouane. "Bottom hole pressure estimation using hybridization neural networks and grey wolves optimization." Petroleum 4, no. 4 (December 2018): 419–29. http://dx.doi.org/10.1016/j.petlm.2018.03.013.

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42

Guo, Wang, Fan Honghai, and Liu Gang. "Design and calculation of a MPD model with constant bottom hole pressure." Petroleum Exploration and Development 38, no. 1 (February 2011): 103–8. http://dx.doi.org/10.1016/s1876-3804(11)60017-7.

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43

Guo, Boyun, Na Wei, Jinze Song, and Jim Lee. "Prediction of the maximum allowable bottom hole pressure in CO2 injection wells." Journal of Petroleum Science and Engineering 156 (July 2017): 575–81. http://dx.doi.org/10.1016/j.petrol.2017.06.033.

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44

Taware, Satyajit, Akhil Dattagupta, and Srikanta Mishra. "Bottom-hole Pressure Data Integration for CO2 Sequestration in Deep Saline Aquifers." Energy Procedia 63 (2014): 4485–507. http://dx.doi.org/10.1016/j.egypro.2014.11.484.

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45

Petrov, N. S., I. I. Tseplyaev, and A. A. Makeev. "Determination of optimal bottom hole pressure using hydrodynamic studies of producing wells." Neftyanoe khozyaystvo - Oil Industry, no. 10 (2021): 82–84. http://dx.doi.org/10.24887/0028-2448-2021-10-82-84.

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46

Kang, Qing Ying, and Xiao Hui Cao. "The Analysis for Influence of Connecting Rod Strength with the Change of Interference of Connecting Rod Small End Bushing." Advanced Materials Research 602-604 (December 2012): 2151–54. http://dx.doi.org/10.4028/www.scientific.net/amr.602-604.2151.

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Stress analysis was performed for certain connecting rod assembly by the finite element method, exploring the influence of connecting rod strength with the change of interference. After calculation, it was found that the stress in oil hole of connecting rod small end and bottom edge in the inner hole of connecting rod small end was large. Through the comparison of the different scheme, it got that : the change of the interference of connecting rod small end bushing had a great effect on the stress in oil hole and bottom edge. The increasing of interference made the stress of the bottom edge in the inner hole increase gradually and basically linearly; The maximum stress of oil hole decreased at first, and then increased. Without considering interference, maximum stress was 117MPa. When the interference was 0.01mm, maximum stress got the minimum value about 96MPa. After it, with the increasing of interference, maximum stress increased gradually. When the interference is relatively small, the breakout pressure plays a key role in the stress of oil hole of connecting rod small end, and when the interference is relatively large, the interference plays the leading role.

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47

Mao, Liangjie, Mingjie Cai, Qingyou Liu, and Guorong Wang. "Dynamical well-killing simulation of a vertical H2S-containing natural gas well." Oil & Gas Science and Technology – Revue d’IFP Energies nouvelles 75 (2020): 71. http://dx.doi.org/10.2516/ogst/2020065.

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This work aims to explore the dynamical well-killing process of a vertical H2S-containing natural gas well. A dynamical well-killing model considering an H2S solubility was established to simulate the overflow and well-killing process of a vertical H2S-containing natural gas well. The mass and momentum equations of the coupled model were solved using finite difference method, while the transient temperature prediction model was solved using finite volume method. The coupled model was validated by reproducing experimental data and field data of Well Tiandong #5. The effect of H2S content, mud displacement, drilling fluid density, and initial overflow volume on the dynamical well-killing process of an H2S-containing natural gas well were obtained and analyzed in this work. Results showed that H2S will gasify near wellhead during well killing when casing pressure decreases. To balance the bottom hole pressure, when H2S releases, the casing pressure increases as H2S content increases. As initial overflow volume increases, the annular temperature, annular pressure and the casing pressure increase significantly. When H2S gasifies, the casing pressure applied at wellhead should be higher at lower initial overflow volume to balance bottom hole pressure. In the well-killing process, the annular pressure and temperature decrease as drilling fluid density increases and a lower casing pressure is needed for balancing bottom hole pressure. The casing pressure is lower at a higher displacement for higher friction resistance. Besides, as well-killing displacement increases H2S will gasify at an earlier time. When drilling for H2S-containing natural gas well, early detection of gas kick should be more frequent to avoid severe overflow. Besides, higher displacement and density of drilling fluid should be considered to avoid stratum fracturing and prevent leakage accidents under the premise of meeting drilling requirements.

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Yin, Dai Yin, Wei Zhou, Jian Xin Lu, and Cheng Li Zhang. "Interference between the Gas Wells in the Method of the Pesudo-Pressure." Applied Mechanics and Materials 229-231 (November 2012): 2606–9. http://dx.doi.org/10.4028/www.scientific.net/amm.229-231.2606.

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During the developing process of gas reservoirs, different gas well spacing will affect the production of the well and the bottom hole pressure. In this paper, the method of the advanced mechanics of fluids in porous media, the pressure changes into the pesudo-pressure, the changes of the pressure near the well have been obtained. Theoretical model of the gas reservoir has been established, which is built with constant pressure as internal boundary control conditions and infinite formation as outer boundary control conditions. According to the seepage differential equations of the pesudo-pressure, the changes in the production on bottom pressure can be derived in different well spacing. Then the pressure and production curves have been drawn.

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Kira, Akio, Kazuyuki Hokamoto, Yasuhiro Ujimoto, Shoichiro Kai, and Masahiro Fujita. "Collection of Product Synthesized Using Extremely High Impulsive Pressure Generator." Materials Science Forum 566 (November 2007): 315–20. http://dx.doi.org/10.4028/www.scientific.net/msf.566.315.

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A new method has been developed to generate an extremely high impulsive pressure by using a metal jet that is discharged when a metal collides with another metal. The high pressure is used to synthesize a new material. When a metal plate was accelerated by the detonation of an explosive, it collides with the concentric circle of the conic surface of a conical concave metal block metal jets are discharged from all parts on the concentric circle. The metal jets fly toward the center while converging and collide with each other at the central axis. Because those collide at high-speed pressure becomes extremely high. The flight direction of the converged metal jet changes downward. The metal jet collides with the bottom of the block. A large hole is formed inside the bottom. The formation process of the hole was examined by the observation of the section of the block. A specimen powder that was rubbed to the conic surface is discharged with the metal jet and become the high pressure. The specimen powder is synthesized to a different material. The synthesized material is held inside the formed hole. The existence of cBN was confirmed by the X-ray diffraction of the synthesized material, in the case that BN was used as the specimen powder. Similarly, the existence of diamond was confirmed in the case of graphite powder.

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50

Yao, Tingwei, Yang Zhang, Minhao Guo, Zhilin Tuo, Haiyang Wang, and Desheng Zhou. "Case study on diagnosis and identify the degree of bottom hole liquid accumulation in double-branch horizontal wells in PCOC." E3S Web of Conferences 248 (2021): 01071. http://dx.doi.org/10.1051/e3sconf/202124801071.

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In the process of continuous production of natural gas wells, formation pressure and gas flow rate decrease continuously. The ability to carry liquid decreases continuously, thus gradually forming bottom hole liquid. Bottom hole liquid accumulation is an important reason for the decrease of production or shutdown of natural gas wells. How to diagnose whether there is liquid accumulation in natural gas wells and identify the degree of liquid accumulation, to adopt drainage gas recovery operation in time, is the research focus of efficient development of natural gas reservoirs. In this paper, a method for diagnosing bottom hole liquid accumulation combining production performance curve and modified Fernando inclined well critical liquid-carrying model is designed for a large scale double-branch horizontal well used in unconventional reservoirs. The method is applied to the Well X2 of He 8 Member in PCOC. The application results showed that there was no liquid accumulation in the horizontal and vertical sections of the Well X2. The liquid in the wellbore was generated at the bottom of the inclined section and the liquid accumulation is upward along the wellbore from the bottom of the inclined section, with the height of 3 m.

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Journal articles on the topic 'Bottom-hole pressure'

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