Academic literature on the topic 'Monovalent lons'
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Journal articles on the topic "Monovalent lons"
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Tölgyesi, F., S. Györgyi, and I. P. Sugár. "Effect of Monovalent lons on the Phase Transition Behavior of DPPC-Water Dispersion." Molecular Crystals and Liquid Crystals 128, no. 3-4 (1985): 263–75. http://dx.doi.org/10.1080/00268948508079495.
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Patiño, Reynaldo, and Carl B. Schreck. "Spontaneous and ACTH-induced interrenal steroidogenesis in juvenile coho salmon (Oncorhynchus kisutch): Effects of monovalent lons and osmolality in vitro." General and Comparative Endocrinology 69, no. 3 (1988): 416–23. http://dx.doi.org/10.1016/0016-6480(88)90033-0.
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Schamel, Wolfgang W. A., Ignacio Arechaga, Ruth M. Risueño, et al. "Coexistence of multivalent and monovalent TCRs explains high sensitivity and wide range of response." Journal of Experimental Medicine 202, no. 4 (2005): 493–503. http://dx.doi.org/10.1084/jem.20042155.
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A long-standing paradox in the study of T cell antigen recognition is that of the high specificity–low affinity T cell receptor (TCR)–major histocompatibility complex peptide (MHCp) interaction. The existence of multivalent TCRs could resolve this paradox because they can simultaneously improve the avidity observed for monovalent interactions and allow for cooperative effects. We have studied the stoichiometry of the TCR by Blue Native–polyacrylamide gel electrophoresis and found that the TCR exists as a mixture of monovalent (αβγεδεζζ) and multivalent complexes with two or more ligand-binding TCRα/β subunits. The coexistence of monovalent and multivalent complexes was confirmed by electron microscopy after label fracture of intact T cells, thus ruling out any possible artifact caused by detergent solubilization. We found that although only the multivalent complexes become phosphorylated at low antigen doses, both multivalent and monovalent TCRs are phosphorylated at higher doses. Thus, the multivalent TCRs could be responsible for sensing low concentrations of antigen, whereas the monovalent TCRs could be responsible for dose-response effects at high concentrations, conditions in which the multivalent TCRs are saturated. Thus, besides resolving TCR stoichiometry, these data can explain how T cells respond to a wide range of MHCp concentrations while maintaining high sensitivity.
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Zhang, Guozhu, Chen Wang, Wataru Mizukami, et al. "Monovalent sulfur oxoanions enable millimeter-long single-crystalline h-WO3 nanowire synthesis." Nanoscale 12, no. 16 (2020): 9058–66. http://dx.doi.org/10.1039/c9nr10565d.
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Monovalent sulfur oxoanions (HSO<sub>4</sub><sup>−</sup> and CH<sub>3</sub>SO<sub>3</sub><sup>−</sup>), rather than the previously proposed SO<sub>4</sub><sup>2−</sup>, significantly promote the anisotropic nanowire growth of hexagonal WO<sub>3</sub>.
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Ghosh, Amalendu, Supriyo De, Jeremiah Bell, et al. "Generation and resolution of bivalent chromatin during hematopoiesis (HEM2P.259)." Journal of Immunology 192, no. 1_Supplement (2014): 50.4. http://dx.doi.org/10.4049/jimmunol.192.supp.50.4.
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Abstract Bivalent promoters, that are simultaneously marked by activation- and repression-associated histone modifications, have been proposed to maintain ES cell genes in a poised configuration. During differentiation such promoters resolve to fully active or inactive states, with associated changes in gene expression. Here we followed the fate of bivalent promoters during hematopoietic stem cell (HSC) differentiation to T lymphoid lineage committed cells. We show that HSC bivalents interconverted between monovalent and bivalent chromatin states at sequential developmental stages, with only a minority resolving to either monovalent state for the long-term. Conversely, bivalent promoters that were generated de novo interconverted between precursor states and bivalency. Neither generation nor resolution of bivalency was accompanied by changes in gene expression. Moreover, singly marked genes did not transition to the opposing monovalent state via a bivalent intermediate. Our observations reveal unprecedented dynamics of bivalent chromatin during hematopoiesis that suggests a developmental role beyond poising genes for future resolution.
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Wu, Qi, Xian Liu, Yeshuang Du, Chunlin Teng, and Fei Liang. "Nonlinear organic–inorganic halide hybrids containing unprecedented linear [MIX2]− coordination units and quasi-two-dimensional lone pairs." Chemical Communications 56, no. 36 (2020): 4894–97. http://dx.doi.org/10.1039/d0cc01532f.
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A first example of monovalent-metal-based hybrid halides [N(CH<sub>3</sub>)<sub>4</sub>]MCl<sub>2</sub> (M = Ga<sup>+</sup>, In<sup>+</sup>) with zero-dimensional configuration containing unprecedented linear [GaCl<sub>2</sub>]/[InCl<sub>2</sub>] units have been designed and synthesized.
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Li, Yaohua, Martin Girard, Meng Shen, Jaime Andres Millan, and Monica Olvera de la Cruz. "Strong attractions and repulsions mediated by monovalent salts." Proceedings of the National Academy of Sciences 114, no. 45 (2017): 11838–43. http://dx.doi.org/10.1073/pnas.1713168114.
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Controlling interactions between proteins and nanoparticles in electrolyte solutions is crucial for advancing biological sciences and biotechnology. The assembly of charged nanoparticles (NPs) and proteins in aqueous solutions can be directed by modifying the salt concentration. High concentrations of monovalent salt can induce the solubilization or crystallization of NPs and proteins. By using a multiscale coarse-grained molecular dynamics approach, we show that, due to ionic correlations in the electrolyte, NPs pairs at high monovalent salt concentrations interact via remarkably strong long-range attractions or repulsions, which can be split into three regimes depending on the surface charge densities of the NPs. NPs with zero-to-low surface charge densities interact via a long-range attraction that is stronger and has a similar range to the depletion attraction induced by polymers with radius of gyrations comparable to the NP diameter. On the other hand, moderately charged NPs with smooth surfaces as well as DNA-functionalized NPs with no possibility of hybridization between them interact via a strong repulsion of range and strength larger than the repulsion predicted by models that neglect ionic correlations, including the Derjaguin–Landau–Vervey–Overbeek (DLVO) model. Interactions between strongly charged NPs (>2 e/nm2), both types smooth and DNA-functionalized NPs, show an attractive potential well at intermediate-to-high salt concentrations, which demonstrates that electrolytes can induce aggregation of strongly charged NPs. Our work provides an improved understanding of the role of ionic correlations in NP assembly and design rules to utilize the salting-out process to crystallize NPs.
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Shuchita, Chandorkar, Shouche Shobha, and Pathak Jpn. "Impact of Starvation on Worms and ionic composition of Haemolymph of Philosamia Ricini." Biolife 4, no. 2 (2022): 382–85. https://doi.org/10.5281/zenodo.7318601.
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<strong>ABSTRACT</strong> The fifth instar larvae of <em>Philosamia ricini</em> were reared under food stress. These were kept on starvation for three days. After that the haemolymph was taken for the analysis. Monovalent cations sodium, potassium and divalent cations calcium and magnesium were estimated, to observe the impact of starvation. With respect to ther control worms Na+ ions increased significantly while Mg++ ions showed rather insignificant change. Divalent cation Calcium showed an insignificant change but Magnesium ions showed a significant decrease. <strong>KEYWORDS:</strong> Haemolymph, monovalent cation, divalent cation, starvation, <strong>REFERENCES</strong> Asperen, K. van and Esch, I.van (1956). The chemical composition of haemolymph in <em>Periplaneta americana. Arch.</em> <em>Neerl. Zool</em>. <strong>11</strong>, 342. Brady J. (1967a). Haemocytes and measurement of porassium in insect blood. <em>Nature, Lond</em>., <strong>215,</strong> 96-7. Brady J. (1967b). The relationship between blood ions and blood-cell density in insects. <em>J. exp. Biol</em>. <strong>47,</strong> 313-26. Cohen, A. C. and Patana, R. (1982). Ontogenetic and stress related changes in the haemolymph chemistry of beet armyworms. Comp. Biochem. Physiol. 71A, 193. Florkin M. and Jeuniaux C. (1974). Haemolymph: composition. In <em>The physiology of Insects</em>. Vol. V, pp.256-307. Nicolson, et al. (1974). Effects of starvation and dehydration on osmotic and ionic balance in <em>Carasius morosus</em>. <em>J. Insect</em>. <em>Physiol</em>. <strong>20</strong>, 2061-2069. Pant R, and Agarwal,H. C., (1965). <em>Biochem. J.,</em> <strong>96</strong>, 824 Pichon, Y.(1963). La teneur en ions Na<sup>+</sup>, K<sup>+</sup>, et Ca<sup>++</sup> de l`hemolymphe de <em>Periplaneta americana</em> L., ses variations. <em>Bull.</em> <em>Soc. Scient.Bretagne</em> <strong>38</strong>, 147. Pichon Y. and Boistel (1963a). Modifications de la composition ionique de l`hemolymphe d`une blatte, <em>Periplaneta americana,</em> saous I`effect du jeune et de la deshydratation. <em>C. R. Seanc. Soc. Biol. </em><strong>158</strong>, 272. Pichon Y. and Boistel (1963b). Modifications in the ionic content of the haemolymph and of the activity of <em>Periplaneta americana</em> in relation to diet. <em>J. insect Phyiol</em>. <strong>9</strong>, 887-91. Pichon Y. (1970). Ionic content of haemolymph in the cockroach, <em>Periplaneta americana. J. Exp. Biol.,</em> <strong>53</strong>, 195-209. Tobias, J. M. (1948). Potassium, sodium and water interchange in irritable tissues and haemolymph of a omnivorous insect <em>Periplaneta americana. J. Cell. Comp. Physiol</em>. <strong>31</strong>, 125-142. Treherne J. E. (1954a) The exchange of labeled sodium in the larva of <em>Aedes egyptii</em>. <em>L. J. Exp. Biol</em>. <strong>31</strong>, 386-401. Treherne J. E. (1961). Sodium and potassium fluxes in the abdominal nerve cord of the cockroach <em>Periplaneta americana. J. exp. biol.</em> <strong>38</strong>, 315-22
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Soukka, Tero, Janika Paukkunen, Harri Härmä, Stefan Lönnberg, Hanne Lindroos, and Timo Lövgren. "Supersensitive Time-resolved Immunofluorometric Assay of Free Prostate-specific Antigen with Nanoparticle Label Technology." Clinical Chemistry 47, no. 7 (2001): 1269–78. http://dx.doi.org/10.1093/clinchem/47.7.1269.
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Abstract Background: The extreme specific activity of the long-lifetime fluorescent europium(III) chelate nanoparticles and the enhanced monovalent binding affinity of multivalent nanoparticle-antibody bioconjugates are attractive for noncompetitive immunoassay. Methods: We used a noncompetitive, two-step immunoassay design to measure free prostate-specific antigen (PSA). Europium(III) chelate nanoparticles (107 nm in diameter) were coated with a monoclonal anti-PSA antibody (intrinsic affinity, 6 × 109 L/mol). The nanoparticle-antibody bioconjugates had an average of 214 active binding sites per particle and a monovalent binding affinity of 7 × 1010 L/mol. The assay was performed in a low-fluorescence microtitration well passively coated with an another monoclonal anti-PSA antibody (affinity, 2 × 1010 L/mol), and the europium(III) fluorescence was measured directly from the bottom of the well by a standard time-resolved microtitration plate fluorometer. Results: The detection limit (mean + 2 SD) was 0.040 ng/L (7.3 × 105 molecules/mL), and the dynamic detection range covered four orders of magnitude in a 3-h total assay time. The imprecision (CV) over the whole assay range was 2–10%. The detection limit of the assay was limited by the fractional nonspecific binding of the bioconjugate to the solid phase (0.05%), which was higher than the nonspecific binding of the original antibody (&lt;0.01%). Conclusions: The sensitivity of the new assay is equal to that of the ambient-analyte, microspot immunoassay and will be improved by use of optimized, high binding-site density nanoparticle-antibody bioconjugates with reduced nonspecific binding and improved monovalent binding affinity.
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Bryan, J. T., J. F. Smith, W. Ruiz, M. K. Brownlow, M. J. Brown, and M. T. Esser. "Evaluation of antibodies induced by an HPV vaccine to cross-neutralize pseudovirions of vaccine-related HPV types." Journal of Clinical Oncology 24, no. 18_suppl (2006): 15008. http://dx.doi.org/10.1200/jco.2006.24.18_suppl.15008.
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15008 Background: Human papillomavirus (HPV) is the causative agent of cervical cancer. The HPV types 6, 11, 16 and 18 quadrivalent L1 virus-like particle (VLP) vaccine has been shown to be highly efficacious in preventing HPV vaccine type-related disease. The HPV A7 species contains types 18, 45 and 59. The A9 species include types 16, 31, 33, 35, 52 and 58. The potential of the vaccine induced antibodies to cross-neutralize infection of pseudovirions (PsV) of HPV types within the A9 and A7 species was evaluated. Methods: Sera from quadrivalent, monovalent HPV 16, or monovalent HPV 18 vaccinees were evaluated. Sera were tested in a multiplexed competitive Luminex Immunoassay (cLIA) against vaccine types to demonstrate HPV type-specific seroconversion. A9 and A7 VLP type cross-reactive binding ability was assessed by a total IgG LIA. HPV L1 and L2 PsV containing secreted alkaline-phosphatase (SEAP) sequences were constructed using native HPV sequences for 16 and 31 and with mammalian codon-optimized sequences for 18 and 45. Demonstrated expression of SEAP was used as an indirect measure of PsV infection of 293TT cells. Results: All subjects seroconverted to high titers against the vaccine HPV types. Cross-reactive antibodies were generated. Quadrivalent vaccinee sera bound to HPV 31, 45, 52 and 58 VLPs. These total IgG titers were 1.5–2 logs lower than the titers to the vaccine types. PsV types 18 and 45 were neutralized using the 18 monovalent and the quadrivalent sera. At month 7, the PsV 18 neutralization titer was ∼1–1.5 logs less than that required for PsV 45 cross-neutralization. Neutralization studies using PsV of the A9 species are in progress. Conclusions: High titers of anti-HPV antibodies are elicited by vaccination with HPV VLP vaccines. These antibodies can prevent in vitro PsV infection of vaccine-HPV types. Cross-reactive, cross-neutralizing antibodies are generated, however at reduced titers compared to the vaccine-specific types. Antibody titers required for cross-protection against non-vaccine types are not known. [Table: see text]
Book chapters on the topic "Monovalent lons"
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KOSTYUK, P. G. "CALCIUM SIGNALING: KYIV HISTORY." In ESSAYS ON NEUROPHYSIOLOGY BY PLATON KOSTYUK AND HIS STUDENTS. Kyiv: AKADEMPERIODYKA, 2020. https://doi.org/10.15407/biph.books.essneur.021.
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The idea of a particular role of calcium ions in the maintenance of basic functional properties of living cells was expressed almost a century ago. As it has been noticed by the pioneering observations of Ringer (1873) and Loeb (1906), a defi - nite relation between monovalent (sodium) and divalent (calcium) in the external medium is necessary for the execution of active cellular reactions. Th e way to the understanding of the mechanisms of this crucial role of Ca ions has been long and complicated, and our group has quite eff ectively participated in it, and here I would like to remind briefl y how it happened.
Conference papers on the topic "Monovalent lons"
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Oskarsson, Hans, Paul M. Ferm, Kiernan Heck, and Rasoul Nazari Moghaddam. "New Visco-Elastic Surfactant Formulation with Excellent Carrying Properties in Multiple Brine Systems and Wide Temperature Ranges." In SPE International Conference on Oilfield Chemistry. SPE, 2023. http://dx.doi.org/10.2118/213840-ms.
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Abstract Visco-elastic surfactants (VES) are widely used in oil and gas-well drilling and completion operations, mainly due to their non-damaging characteristics and excellent sand and proppant carrying properties. A challenge of VES is to maintain visco-elasticity over a wide set of temperature and brine conditions. The scope of this study was to develop a VES system with a robust rheology stability in low density to high density monovalent and di-valent brines and in wide temperature ranges aiming for a versatile formulation applicable for many conditions. Rheology of VES formulations of zwitterionic and cationic surfactants were screened in a wide range of typical drilling and completion brines with densities ranging from 8.7 −16.5 PPG of different monovalent and divalent salts and in temperatures up to 350 °F. As a final test, the capacity to hold and disperse sand and gravels at different conditions were investigated for selected brine formulations. A specific long-chained zwitterionic surfactant exhibits excellent brine stability in many situations as a stand-alone surfactant and here are shown to show improved temperature and brine stability when formulated with various cationic quarternary ammonium-based surfactants. Further improvements in temperature and brine stability are seen both types of surfactants in the formulation had long tail-groups and in many cases if both had unsaturation. For these formulations, even when changing brine conditions from 8.7 ppg CaCl2/MgCl2 to 16.5 ppg CaCl2/ZnCl2/CaBr2, they show improved visco-elasticity and carrying properties compared to standalone surfactant formulations and in a wide temperature range from 75 °F to above 245 °F. The viscoelastic behavior over broad brine and temperature ranges also showed excellent carrying properties in gravel sedimentation tests. The proposed formulations are of advantage both in water-based drilling and completion fluids and are non-damaging to the formation.
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Affede, Luca, Roberto Lorefice, Larissa Pinto Vieira, Matteo Giubertoni, Lorenzo Buzzi, and Gabriele Carpineta. "Drilling Offshore Wells with HP WBM in Extreme HP HT Conditions." In International Petroleum Technology Conference. IPTC, 2022. http://dx.doi.org/10.2523/iptc-21965-ms.
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Abstract During drilling of three exploration wells challenging conditions encountered, such as temperatures up to 180°C, interbedded highly reactive shales/silts, formation pressures which required mud weights up to 2.35 sg and narrow margin between pore and fracture gradients, posed a host of technical, logistical and cost challenges to Eni activities. These conditions required an accurate drilling fluids design to maximize operational efficiency and to minimize the risks related to such an extreme environment. Technical demands were particularly critical since the reactive shale formations had historically proved to be difficult to inhibit when drilled with Water Based Mud and might have caused swelling, tight hole, sticky wireline runs, bit-balling and accretion that could have resulted, among other issues, in low penetration rates (ROP). The formation nature coupled with ECD (Equivalent Circulation Density) constraints due to the high mud weight required to cope with high pore pressure, which also caused high mud rheology readings, were therefore the main limits to be overcome to achieve the well objectives. A tailored drilling fluid program was thus proposed which consisted of an inhibitive HPWBM (High Performance Water Based Mud) that could be converted to an HT-HPWBM, (High Temperature-High Performances Water Based Mud) while drilling, to cross the deeper and hotter sections of the well. This fluid was specifically engineered and optimized after each well in order to contain high concentration of a combination of monovalent salts to guarantee inhibition and reduce solids loading, dedicated polyamine shale inhibitor and fluid loss additives to minimize API/HPHT filtrate and filter cake thickness with the aim to reduce shale water invasion throughout the drilling campaign, graphite to minimizes fluid invasion and fracture propagation and ROP (Rate Of Penetration) enhancer continuously injected using dedicated pump to act as anti-balling and anti-accretion additive. The achieved results were drilling targets delivered safely, on time and with good overall fluid performances which either reduced or eliminated many of the challenges seen in offset wells, including: no barite sag, rheology stability, and stable long-term mud properties and wellbore conditions even during extended formation logs acquisitions. This paper covers the design, execution and accomplishments of the water-based drilling fluids employed on three HP/HT wells drilled, together with all of the lessons learned captured, highlighting the evolution of these systems to reach a step-change in terms of performances in such a harsh environment.
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Phatak, Alhad, Brian Seymour, Ginger Ren, and Isaias Gonzalez. "Enhancing Performance of High Viscosity Friction Reducers HVFRs in Brine." In SPE International Conference on Oilfield Chemistry. SPE, 2021. http://dx.doi.org/10.2118/204339-ms.
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Abstract High Viscosity Friction Reducers (HVFRs) are often employed in hydraulic fracturing fluids to increase the proppant carrying capacity of slickwater fluids. However, it has been widely reported that the performance of HVFR fluids drops precipitously with even small amounts of salt. This study explores and reports the use of surfactants to alleviate the loss of performance of HVFR fluids due to salinity in the mix water. Fracturing fluids were prepared in the laboratory by mixing the HVFR at concentrations between 2 and 8 gal/1,000 gal with and without surfactant formulations. The viscosities of the fluids were measured on a TA Instruments DHR-3 rheometer using a concentric cylinder geometry. Both anionic and cationic HVFRs were tested with various surfactants. As expected, we observed that HVFR fluids display dramatic loss of viscosity with the addition of as little as 1% salt to the mix water. However, certain surfactant formulations were found to provide a significant boost in viscosity of HVFR fluids in brines over a wide range of shear rates. Increases in viscosity by a factor of as much as 10 times were observed, particularly at low shear rates. The ability of the surfactant formulations to enhance fluid viscosity was observed in both monovalent and divalent model brines, as well as brines that mimicked field produced water compositions. In addition, measurements were also performed in a slot flow device to determine if the results from the rheometer translated to proppant transport characteristics of the fluids. The slot flow results were found to correlate well with fluid viscosity measurements. The fluids containing the surfactant formulation transported nearly 4 times as much proppant as fluids not containing surfactant through a 2.5 ft. long rectangular slot of 0.5 in. thickness at a proppant concentration of 2 lb/gal. An obvious benefit of the approach proposed in this study is that it can enable the use of HVFR fluids in recycled and produced waters, providing both cost and sustainability benefits. Secondly, these surfactant formulations can reduce the amount of HVFR required to obtain a certain target viscosity in brine, thereby reducing the likelihood and potential severity of formation damage from HVFR residue.
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Hassan, Anas M., Emad W. Al-Shalabi, Waleed AlAmeri, Muhammad S. Kamal, Shirish Patil, and Syed M. Shakil Hussain. "New Insights into Hybrid Low Salinity Polymer (LSP) Flooding Through a Coupled Geochemical-Based Modeling Approach." In SPE Annual Technical Conference and Exhibition. SPE, 2022. http://dx.doi.org/10.2118/210120-ms.
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Abstract Low Salinity Polymer (LSP) flooding is one of the emerging synergic techniques in enhance oil recovery (EOR). Previous experimental studies showed an exceptional improvement in displacement efficiency, polymer rheology, injectivity, and polymer viscoelasticity. Nevertheless, when it comes to modeling LSP flooding, it is still challenging to develop a mechanistic predictive model that captures polymer-rock-brine interactions. Therefore, this study employs a coupled geochemical-reservoir numerical model to investigate the effect of water chemistry on polymer-brine-rock geochemical interactions during LSP flooding through varying overall salinity as well as the concentrations of monovalent and divalent ions. In this study, the MATLAB Reservoir Simulation Toolbox (MRST) was coupled with a geochemical interface module i.e., pH-Redox-Equilibrium in C programming language (PHREEQC), termed as IPHREEQC. The coupled MRST-IPHREEQC simulator enables simulating the effects on different parameters on polymer viscosity including the Todd-Longstaff mixing model, inaccessible pore volume, permeability reduction, polymer adsorption, salinity, and shear rate. For describing the related geochemistry, the presence of polymer in the aqueous phase was considered by introducing novel solution specie to the Phreeqc database. Using this coupled simulator, several geochemical reactions and parameters can be assessed including rock and injected water compositions, injection schemes, and other polymer characteristics where the focus of this work is on water chemistry. Moreover, different injection schemes were analyzed including low-salinity water, low-salinity polymer injection (1×LSP), and 5-times spiked low-salinity polymer injection (5×LSP) with their related effects on polymer viscosity. The results showed that polymer viscosity during low-salinity polymer flooding is directly affected by calcium (Ca2+) and magnesium (Mg2+) ions and indirectly affected by sulfate ion (SO42−) as a result of polymer-rock-brine interactions on a dolomite rock-forming mineral. Furthermore, the findings showed that monovalent ions such as sodium (Na+) and potassium (K+) have less pronounced effects on the polymer viscosity. However, the release of calcium (Ca2+) and magnesium (Mg2+) ions due to the dissolution of dolomite led to the formation of polymer (acrylic acid, C3H4O2) complexes and consequently, a pronounced decrease in polymer viscosity. In addition, the increase of sulfate ion (SO42−) concentration in the injected LSP solution affects the interactions between the polymer and positively charged aqueous species and leads to less polymer viscosity loss. Additionally, as a de-risking measure for LSP flood designs, estimating the effect of each ion can be highly useful step. The effect of cations is also related to charge ratio (CR), which renders it the key objective to determine the optimum CR ratio at which viscosity loss of LSP flood is avoided or at least minimal. The coupled simulator works as an integrated tool, which is sound, precise, and adaptable with the ability to encapsulate the reactions required for LSP mechanistic modeling. This paper is among the very few, which describe mechanistic geochemical modeling of the low-salinity polymer flooding technique. The coupled simulator provided new insights into understanding the mechanisms controlling LSP flooding. Based on the findings of this work, several successful low salinity-polymer field pilots can be designed.
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Affede, L., M. Giubertoni, A. Ciuca, L. Bertoldi, L. Pinto Vieira, and G. Carpineta. "Drilling Offshore Wells with High-Performance Water-Based Mud (HPWBM) in Extreme High-Pressure / High-Temperature (HP/HT) Conditions." In SPE Annual Technical Conference and Exhibition. SPE, 2023. http://dx.doi.org/10.2118/214829-ms.
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Abstract During drilling of three exploration wells challenging conditions were encountered including temperatures up to 180°C, interbedded highly reactive shales/silts, formation pressures which required Mud Weights (MW) up to 2.35 SG and narrow margin between pore and fracture gradients, posing a host of technical, logistical, and cost challenges to Eni activities. These conditions required an accurate drilling fluids design to maximize operational efficiency and to minimize the risks related to such an extreme environment. Technical demands were particularly critical since the reactive shale formations had historically proved to be difficult to inhibit when drilled with Water Based Mud (WBM) exhibiting swelling, tight hole, sticky wireline runs, bit-balling and accretion that could have resulted, among other issues, in low penetration rates (ROP). The formation nature coupled with Equivalent Circulation Density (ECD) constraints due to the high mud weight required to cope with high pore pressure, which also caused high mud rheology readings were therefore the main limits to be overcome to achieve the well objectives. A tailored drilling fluid program was thus proposed which consisted of an inhibitive High-Performance Water Based Mud (HPWBM) that could be converted to a High Temperature-High Performances Water Based Mud (HT-HPWBM) while drilling, to cross the deeper and hotter sections of the well. This fluid was specifically engineered and optimized after each well in order to contain high concentration of a combination of monovalent salts to guarantee inhibition and reduce solids loading, dedicated polyamine shale inhibitor and fluid loss additives to minimize API/High-Pressure High-Temperature (HP/HT) filtrate and filter cake thickness with the aim to reduce shale water invasion throughout the drilling campaign, graphite to minimizes fluid invasion and fracture propagation and Rate Of Penetration (ROP) enhancer continuously injected using dedicated pumps to act as anti-balling and anti-accretion additive. In addition to lab testing campaign and mud formulations optimization several drilling operations practices and equipment were introduced on the project taking in account the lessons learned gained by previous wells and experience on similar HP/HT fields contributing on the optimization of drilling performance achieved well by well. The drilling targets were achieved safely, on time and with good overall fluid performance which either reduced or eliminated many of the challenges seen in offset wells, including: no barite sag, rheology stability, and stable long-term mud properties and wellbore conditions even during extended formation logs acquisitions. This paper covers the design, execution and accomplishments of the water-based drilling fluids employed on three HP/HT wells drilled, together with all the lessons learned captured, highlighting the evolution of these systems to reach a step-change in terms of performances in such a harsh environment.
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Sarmah, Pranjal. "High-Density High-Strength Phase Transforming Lost Circulation Material to Cure Severe to Total Losses in Reservoir and Non Reservoir Sections." In Middle East Oil, Gas and Geosciences Show. SPE, 2023. http://dx.doi.org/10.2118/213746-ms.
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Abstract Lost circulation is one of the biggest expenses in terms of rig time and safety in oil and gas well drilling. Uncontrolled lost circulation can results a dangerous pressure control situation and loss of the well. Drilling through large natural fractures is a big challenge. This paper focus on developing high-density, high-strength, Fluid-Gel-Solid based lost circulation material (LCM) using novel surfactant with acid soluble sealant powder to cure the severe losses scenario. Particulate material, polymer based system, cement, resin etc. has been used as lost circulation mitigation solutions but they have their own limitations of particle size, rheology, tolerance to contaminations, strength to cure sever to complete loss events. A novel fluid system is developed to mitigate these issues. Laboratory customization of the fluid has been evaluated with different temperature and pressure conditions. High pressure high temperature (HPHT) consistometer for setting time, rheometer for rheology and ultrasonic analyzer is used for measuring compressive strength. Tolerance to drilling fluids, spacer and cement contamination also evaluated. This acid soluble system has ease of cleaning if premature gelation occurs. The fluid has thixotropic properties, viscous under static condition and shear thinning upon pumping, achieved through mixing of novel amphoteric surfactant along with water and sealant powder. This is a phase transforming fluid where amphoteric surfactant forms elongated worm-like micelle structure in presence of monovalent and/or divalent salts. Rheological study conducted to show the fluids elastic behavior and pumping property. This will help to assess the displacement of the LCM fluid. The sealant powder, working as weighting agent, sets hard with respect to temperature and time; and a setting control additive controls the hardening or setting process. Finally a high compressive strength solid plug is formed which can withstand the losses of fluids into the formation. Another added advantage of the system is – it can be optimized with seawater; fresh water is not a limitation. The fluid technology is based on thixotropic-gelled using novel surfactant that resists the flow and loss of LCM fluid into the fractures once pumping is stopped. Tailor-made system with high-strength acid soluble sealant can be customized for low to high-density fluid formulations as per applications without any additional incremental treatment for seawater.
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Sakai, T., K. Okada, H. Bando, S. Ueshima, N. Tanaka, and O. Matsuo. "ANALYSIS OF THE SECRETION MECHANISM OF TISSUE-TYPE PLASMINOGEN ACTIVATOR IN A HUMAN MELANOMA CELL LINE (BOWES)." In XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1644397.
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The human melanoma cell line (Bowes) secretes tissue-type plasminogen activator (t-PA) into the culture medium. As reported previously, the secretion of t-PA was depressed and t-PA was accumulated in the intracellular compartment at alternative sodium and potassium ion concentrations and also in the presence of monensin, an ionophore for monovalent cations. In the present study, the secretion and intracellular distribution of t-PA were investigated by radioisotope labeling and fractionation of the cell organelles under normal and monensin-treated conditions. Cell homogenate was fractioneted by discontinuous sucrose density gradient ultracentrifugation. The plasminogen activator (PA) activity or t-PA antigenicity in these fractions was not uniformly distributed, but rather localized in those fractions where cell organelles were rich. This implied that t-PA was enclosed by the intracellular membranous system. Cells were incubated with 35s-methionine and/or 3H-mannose to produce labeled intracellular glycoproteins including t-PA and its premature intermediates, which were separated by immunological adsorption to rabbit anti t-PA IgG-protein A Sepharose. Pulse labeling with 35s-methionine (3 min) demonstrated that intracellular t-PA was transported from the heavier fractions (rER), via intermediate ones (Golgi complex), to lighter ones. The radioactivity of the intracellular t-PA reached a maximum in 30 min, while that of secreted t-PA was observed in 30 min and increased linearly at least for the following 20 min. Enzymography revealed the major intracellular PA activity at 72 kDa and minor activity at 50 kDa. Monensin treatment (10 μM, 6 hr) caused accumulation of the 72 kDa component which was immunologically homologous to secreted t-PA. After long term (3 hr) simultaneous 35s-methionine and 3H-mannose labeling, the radioactivity ratio (3H/35S) the intracellular t-PA was increased in the presence of monensin. These results suggest that some sugar chain(s) in the t-PA molecule are of high mannose type, which is interfered with by monensin in the course of the intracellular processing and transport of t-PA.
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Ismail, Ahmed, Jacques Butcher, Ibrahim Elsayed, et al. "Engineered Low Rheology Water-Based Fluid with Nanocomposite Sealant Technology Improves Drilling Performance in Hard Rock Formations." In SPE Conference at Oman Petroleum & Energy Show. SPE, 2025. https://doi.org/10.2118/225089-ms.
Full textAbstract:
Abstract This paper details the pivotal role of a low solids, low rheology monovalent brine-based drilling fluid (LS-LR-DF) in drilling a vertical, onshore well through hard rock formations. The engineered LS-LR-DF contained a combination of a dual-function synthetic polymer (DFSP) and a nanocomposite wellbore sealant (NCWS). This approach delivered increased stability and performance of the fluid at elevated temperatures in a slim hole well design. The LS-LR-DF application resulted in a significant improvement in drilling efficiency through hard rock formations when compared to offset wells drilled with a high temperature (HT) salt polymer fluid. The target fluid formulation required a low rheology to reduce standpipe pressure (SPP) at high flow rates to facilitate hydraulic horsepower delivery at the bit whilst supporting hole cleaning considerations. Furthermore, the fluid also needed to have sufficient filtration and sealing characteristics at elevated downhole temperatures of ~150°C static downhole temperatures (sDHT) and high overbalance conditions (~1,000 psi) across tight formations with permeabilities up to 4.04 mD. During well execution, the performance of the LS-LR-DF was evaluated with the analysis of hydraulics, standpipe pressure, equivalent circulating density (ECD), and hole cleaning efficiency. Throughout the section, the fluid proved easy to maintain with low rheology supporting hole cleaning in a turbulent flow regime and readily controllable filtration properties (HPHT and PPT). Two round trips were completed without overpull or drag being observed. The actual sDHT was 148.4°C. The higher spurt loss increased initial invasion and the depth of cut from the drill bit. This resulted in a higher ROP compared to the offset wells drilled with the HT salt polymer fluid. The ROP improvement was twofold higher than the 10 previous wells drilled with the HT polymer fluid and resulted in a seven-day reduction in drilling time for the 6-in. interval. The DFSP and NCWS helped mitigate the risk of differential sticking in the low solids fluid through controlled total filtration rates under high temperature conditions that resulted in a thin, low permeability filter cake. The engineered LS-LR-DF yielded a low rheology fluid with higher spurt loss and increased hydraulic horsepower, and jet force impact resulting in lower standpipe pressure (SPP). This softened the drilled formation and doubled the ROP in hard rock formations.
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Rousseau, David, and Mathieu Salaün. "Impact Of Cation Exchange On Polymer In-Situ Viscosity: An Experimental Investigation For A Low-Salinity Polymer Flooding Case." In International Petroleum Technology Conference. IPTC, 2023. http://dx.doi.org/10.2523/iptc-22907-ms.
Full textAbstract:
Abstract Cation exchange occurs when water with a different salinity as the connate brine is injected in a reservoir. During polymer flooding operations, the potential release of divalent cations by the rock can have a detrimental impact on the in-situ viscosity in the polymer bank. The objective of this work was to assess for the risk related to cations exchange in an Argentinian oilfield and to provide guidelines for the injection water design. Reservoir rock samples were first submitted to mineralogical analysis involving scanning-electron microscopy (SEM), X-Ray Diffraction (XRD) and determination of their Cation Exchange Capacities (CEC). Coreflood tests were then performed where the effluents were analyzed for their cations composition. In these experiments, two main scenarios for the composition of the low-salinity injection water (with or without softening) were investigated and the transport properties of the polymer were determined. As a more exploratory approach, polymer was also injected in a 12-meter-long slim tube filled with crushed reservoir rock, to assess if it could be exposed to released cations. The results showed that all reservoir rocks investigated had high CEC, which was consistent with their high clay contents, and that significant cations exchanges took place during low salinity water injection, although no formation damage occurred, showing the stability of the clays. During injection of the softened water, evidences of significant divalent (and monovalent) cations release from the rock were found. During injection of the unsoftened water, a marked and long-term adsorption of the injected calcium cations was observed, corresponding to a depletion in calcium of the injected water. This suggests that, quite counter-intuitively, using unsoftened water as polymer make up water could be interesting in view of economics because the cations exchanges could entail an increase of the in-situ viscosity. The coreflood test results also showed that the presence of polymer in the injected water had no impact on the cations exchanges mechanisms. The partial results from the slim tube injection test suggested, however, that the retardation of the polymer bank caused by polymer adsorption was sufficient to avoid for its viscosity to be affected by the changes in cations distribution. This study illustrates the importance of cation exchange mechanisms and their potential impact for polymer flooding. It also shows that these effects can be investigated in a representative manner at the lab and that practical guidelines for the composition of the polymer injection water can be deduced from the experiments, provided a risk for in-situ viscosity reduction is identified.
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Affede, L., M. Giubertoni, A. Ciuca, et al. "Extreme Efficiency from High Performance Water-Based Mud Under HPHT Conditions." In ADIPEC. SPE, 2023. http://dx.doi.org/10.2118/216620-ms.
Full textAbstract:
Abstract While drilling a campaign of three exploration wells, challenging conditions were encountered which included high temperatures up to 180°C, highly reactive interbedded shales/silts, high formation pressures which required fluid densities up to 2.35 SG and narrow drilling margin between pore and fracture gradients. These conditions posed a host of technical, logistical, and cost challenges to operator's activities and required an accurate drilling fluid design to maximize operational efficiency and to minimize the risks related to drilling in such an extreme environment. Technical demands on the fluid were particularly critical since the reactive shale formations had historically proved to be difficult to inhibit when drilled with water-based mud (WBM) exhibiting swelling, tight hole, failures in open-hole wireline logging operations, bit-balling and accretion that could have resulted, among other issues, in low rates of penetration (ROP). In order to achieve the well objectives high mud rheology readings, caused by the formation nature coupled with equivalent circulation density (ECD) constraints due to the high mud weight required to address the high pore pressure, were therefore a key limitation to overcome. A tailored drilling fluid program was proposed which consisted of an inhibitive, high-performance water-based mud (HP Fluid) that could be converted to a high temperature, high performance water based mud (XP Fluid) while drilling, prior to entering the deeper and hotter sections of the well. The specifically engineered fluid was optimized after each well. A combination of monovalent salts at high concentration was used to guarantee inhibition and reduce solids loading in conjunction with a dedicated polyamine shale inhibitor and fluid loss additives to minimize API/High-Pressure High-Temperature (HP/HT) filtration and filter cake thickness, with the aim of reducing water invasion into the shale. Throughout the drilling campaign graphite was used to minimize fluid invasion and fracture propagation and ROP enhancer was continuously injected using dedicated pumps to act as an anti-balling and anti-accretion additive. In addition to an extensive laboratory testing campaign and optimization of the mud formulations new equipment and several optimized drilling practices were introduced on the project taking in account the lessons learned from previous wells and experience on similar HP/HT fields which contributed to the improvement in drilling performance achieved well by well. The drilling targets were achieved safely, on time and with good overall fluid performance, which either reduced or eliminated many of the challenges seen in offset wells, including: no barite sag, rheology stability, and stable long-term mud properties and wellbore conditions even during extended periods of formation log acquisition. This paper covers the design, execution and accomplishments of the water-based drilling fluids employed on three HP/HT wells drilled, together with all the lessons learned captured, highlighting the evolution of these systems to reach a step-change in terms of performance in such a harsh environment.