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Effect Of Changing Injection Water Salinity On Oil Recovery From Oil Wet Carbonate Rocks
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Book Synopsis Effect of Changing Injection Water Salinity on Oil Recovery from Oil-wet Carbonate Rocks by : Ugur Pakoz
Download or read book Effect of Changing Injection Water Salinity on Oil Recovery from Oil-wet Carbonate Rocks written by Ugur Pakoz and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Experimental studies and some field applications have shown that tuning the salinity of the injected water can affect oil recovery from water flooding. Most of the available literature has dedicated efforts to investigate the effect of low salinity water injection, especially for sandstone. Further studies on carbonate rocks also proved that low salinity effect might be observed for carbonate rocks as well. The main mechanism for the improved oil recovery from low salinity water flooding has been attributed to wettability alteration. The purpose of this work is to further investigate the effect of water salinity on oil recovery from oil-wet carbonate rocks. A series of core flood experiments were performed in the laboratory to measure and compare oil recovery from increasing and decreasing salinity floods at room temperature. Selected carbonate cores were aged with synthetic oil at 100 oC for 12 days prior to core flooding. Contact angles were measured on pre-aged and post-aged core slices to validate aging procedure and oil-wet conditions. Both, increasing and decreasing salinity floods showed measurable recovery gains in the secondary and tertiary modes compared with initial floods. In case of increasing water salinity, 1.3% and 0.6% additional recoveries were obtained while in the case of decreasing water salinity, additional recoveries were 0.6% and 0.7%, all in terms of original oil in place in the core. Results suggest that the system disturbance caused by the change in injection water salinity may have a greater influence on oil recovery than wettability alteration under the laboratory conditions tested.
Book Synopsis Low Salinity and Engineered Water Injection for Sandstone and Carbonate Reservoirs by : Emad Walid Al Shalabi
Download or read book Low Salinity and Engineered Water Injection for Sandstone and Carbonate Reservoirs written by Emad Walid Al Shalabi and published by Gulf Professional Publishing. This book was released on 2017-06-14 with total page 179 pages. Available in PDF, EPUB and Kindle. Book excerpt: Low Salinity and Engineered Water Injection for Sandstone and Carbonate Reservoirs provides a first of its kind review of the low salinity and engineered water injection (LSWI/EWI) techniques for today’s more complex enhanced oil recovery methods. Reservoir engineers today are challenged in the design and physical mechanisms behind low salinity injection projects, and to date, the research is currently only located in numerous journal locations. This reference helps readers overcome these challenging issues with explanations on models, experiments, mechanism analysis, and field applications involved in low salinity and engineered water. Covering significant laboratory, numerical, and field studies, lessons learned are also highlighted along with key areas for future research in this fast-growing area of the oil and gas industry. After an introduction to its techniques, the initial chapters review the main experimental findings and explore the mechanisms behind the impact of LSWI/EWI on oil recovery. The book then moves on to the critical area of modeling and simulation, discusses the geochemistry of LSWI/EWI processes, and applications of LSWI/EWI techniques in the field, including the authors’ own recommendations based on their extensive experience. It is an essential reference for professional reservoir and field engineers, researchers and students working on LSWI/EWI and seeking to apply these methods for increased oil recovery. Teaches users how to understand the various mechanisms contributing to incremental oil recovery using low salinity and engineering water injection (LSWI/EWI) in sandstones and carbonates Balances guidance between designing laboratory experiments, to applying the LSWI/EWI techniques at both pilot-scale and full-field-scale for real-world operations Presents state-of-the-art approaches to simulation and modeling of LSWI/EWI
Book Synopsis Modeling the Effect of Injecting Low Salinity Water on Oil Recovery from Carbonate Reservoirs by : Emad W. Al Shalabi
Download or read book Modeling the Effect of Injecting Low Salinity Water on Oil Recovery from Carbonate Reservoirs written by Emad W. Al Shalabi and published by Emad W. Al Shalabi. This book was released on 2014 with total page 697 pages. Available in PDF, EPUB and Kindle. Book excerpt: The low salinity water injection technique (LSWI) has become one of the important research topics in the oil industry because of its possible advantages for improving oil recovery. Several mechanisms describing the LSWI process have been suggested in the literature; however, there is no consensus on a single main mechanism for the low salinity effect on oil recovery. As a result of the latter, there are few models for LSWI and especially for carbonates due to their heterogeneity and complexity. In this research, we proposed a systematic approach for modeling the LSWI effect on oil recovery from carbonates by proposing six different methods for history matching and three different LSWI models for the UTCHEM simulator, empirical, fundamental, and mechanistic LSWI models. The empirical LSWI model uses contact angle measurements and injected water salinity. The fundamental LSWI model captures the effect of LSWI through the trapping number. In the mechanistic LSWI model, we include the effect of different geochemical reactions through Gibbs free energy. Moreover, field-scale predictions of LSWI were performed and followed by a sensitivity analysis for the most influential design parameters using design of experiment (DoE). The LSWI technique was also optimized using the response surface methodology (RSM) where a response surface was built. Also, we moved a step further by investigating the combined effect of injecting low salinity water and carbon dioxide on oil recovery from carbonates through modeling of the process and numerical simulations using the UTCOMP simulator. The analysis showed that CO2 is the main controller of the residual oil saturation whereas the low salinity water boosts the oil production rate by increasing the oil relative permeability through wettability alteration towards a more water-wet state. In addition, geochemical modeling of LSWI only and the combined effect of LSWI and CO2 were performed using both UTCHEM and PHREEQC upon which the geochemical model in UTCHEM was modified and validated against PHREEQC. Based on the geochemical interpretation of the LSWI technique, we believe that wettability alteration is the main contributor to the LSWI effect on oil recovery from carbonates by anhydrite dissolution and surface charge change through pH exceeding the point of zero charge.
Book Synopsis Modeling the Effect of Injecting Low Salinity Water on Oil Recovery from Carbonate Reservoirs by : Emad W. Al Shalabi
Download or read book Modeling the Effect of Injecting Low Salinity Water on Oil Recovery from Carbonate Reservoirs written by Emad W. Al Shalabi and published by Emad W. Al Shalabi. This book was released on 2014-10-20 with total page 697 pages. Available in PDF, EPUB and Kindle. Book excerpt: The low salinity water injection technique (LSWI) has become one of the important research topics in the oil industry because of its possible advantages for improving oil recovery. Several mechanisms describing the LSWI process have been suggested in the literature; however, there is no consensus on a single main mechanism for the low salinity effect on oil recovery. As a result of the latter, there are few models for LSWI and especially for carbonates due to their heterogeneity and complexity. In this research, we proposed a systematic approach for modeling the LSWI effect on oil recovery from carbonates by proposing six different methods for history matching and three different LSWI models for the UTCHEM simulator, empirical, fundamental, and mechanistic LSWI models. The empirical LSWI model uses contact angle measurements and injected water salinity. The fundamental LSWI model captures the effect of LSWI through the trapping number. In the mechanistic LSWI model, we include the effect of different geochemical reactions through Gibbs free energy. Moreover, field-scale predictions of LSWI were performed and followed by a sensitivity analysis for the most influential design parameters using design of experiment (DoE). The LSWI technique was also optimized using the response surface methodology (RSM) where a response surface was built. Also, we moved a step further by investigating the combined effect of injecting low salinity water and carbon dioxide on oil recovery from carbonates through modeling of the process and numerical simulations using the UTCOMP simulator. The analysis showed that CO2 is the main controller of the residual oil saturation whereas the low salinity water boosts the oil production rate by increasing the oil relative permeability through wettability alteration towards a more water-wet state. In addition, geochemical modeling of LSWI only and the combined effect of LSWI and CO2 were performed using both UTCHEM and PHREEQC upon which the geochemical model in UTCHEM was modified and validated against PHREEQC. Based on the geochemical interpretation of the LSWI technique, we believe that wettability alteration is the main contributor to the LSWI effect on oil recovery from carbonates by anhydrite dissolution and surface charge change through pH exceeding the point of zero charge.
Book Synopsis An Experimental Study of the Impact of Injection Water Composition on Oil Recovery from Carbonate Rocks by : Mohammed J. Alshakhs
Download or read book An Experimental Study of the Impact of Injection Water Composition on Oil Recovery from Carbonate Rocks written by Mohammed J. Alshakhs and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Evidence from laboratory studies and field tests suggests that implementing certain modifications to the ionic composition of the injection brine leads to greater oil recovery from sandstone rocks. More recent studies indicate that salinity and ionic composition impact oil recovery from carbonate rocks. The mechanisms that take place and techniques of altering the salinity may be different from those experienced in clastic systems. This work examines experimentally the factors that influence oil recovery from carbonate rocks when the salinity is altered. It also investigates mechanisms that lead to greater oil recovery. A series of forced imbibition experiments were conducted at different total salinity and ionic composition using reservoir limestone cores and crude-oil. Brines of different salinities were injected sequentially into a core with realistic initial oil and water saturation. Additional incremental oil recovery of 4.4-6.4% of the original oil in place (OOIP) was observed, during the tertiary stage, when the injection seawater, that has a salinity of 55 kppm, was replaced by a new brine (MgSO4) of similar total salinity (45 kppm) and rich in Mg2+ and SO42- ions. The effect of reducing the total salinity was evaluated using outcrop limestone cores and another crude- oil. An incremental oil recovery increase of 3.2-6.5% was observed when twice-diluted seawater (29 kppm) was injected during the tertiary stage following seawater injection. Direct measurements of crude-oil contact-angles on smooth calcite surfaces suggest that the release of oil is caused by a wettability shift toward water wetness. The static water contact-angle was reduced from 92.9 to 58.7 when the brine was switched from seawater to MgSO4 solution of similar salinity. Similar reduction was observed when measurements were conducted using the fluids of the second system. The static water contact-angle was reduced from 70.1 to 58.9 when the brine was switched from seawater to twice-diluted seawater. The contribution of each component of the rock/brine/oil system to the wettability was evaluated by measuring zeta potential of water/oil and water/solid interfaces. DLVO (Derjaguin, Landau, Verwey, and Overbeek) theory of surface forces uses the measurements to predict disjoining pressure and contact-angle. The results rationalized observations of recovery and crude-oil adhesion to solids. They also show that Mg2+ ions play a key role in the wettability alteration process when MgSO4 brine was used and no significant contribution was observed for SO42- ions. For tests that used the twice diluted seawater, the wettability alteration was attributed to the additional Ca2+ ions that added to the brine from the rock dissolution. Conventional fluid flow simulation was able to predict the additional oil recovery that was observed in the core-flood experiments. The input relative permeabilities for each brine were generated using pore network modeling that simulated flow in a carbonate system under different wettability conditions.
Book Synopsis LABORATORY INVESTIGATION OF OIL-COMPOSITION AFFECTING THE SUCCESS OF LOW-SALINITY WATERFLOODING IN OIL-WET CARBONATE ROCKS. by : Gregory Kojadinovich
Download or read book LABORATORY INVESTIGATION OF OIL-COMPOSITION AFFECTING THE SUCCESS OF LOW-SALINITY WATERFLOODING IN OIL-WET CARBONATE ROCKS. written by Gregory Kojadinovich and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Improved oil recovery via wettability alteration by tuning the ionic composition of the injection water has been thoroughly researched in recent years. It has been well documented that seawater can increase the water wetness of chalk at high temperature. Forced displacement and spontaneous imbibition experiments have attributed the wettability alteration to interactions between active ions in the brine, Ca2+, Mg2+, and SO42-, the rock surface, and the oil phase. It has been suggested that the adsorption of SO42- onto the rock surface causes the bond between adsorbed carboxylic material in the crude oil and the rock surface to deteriorate which causes the release of the crude oil. Reduction in ionic strength of the injection water has also been proposed to trigger the effect of wettability alteration in carbonates. Although the numerous experiments devoted to understanding the mechanisms governing the low salinity effect in the past two decades, there has been no consensus about the dominant mechanisms driving wettability alteration. The purpose of this research is to improve the understanding of how reduced ionic strength and potentially determining ions (PDIs) contribute to oil recovery, as well as provide a direct comparison of their oil recovery performance for a synthetic oil versus crude oil during waterflooding. For this, a series of waterflood experiments were conducted in the laboratory at 90 C in Indiana limestone core plugs. Chemically tuned brines derived from seawater were used in secondary and tertiary recovery modes to displace synthetic oil. A waterflood with formation brine was also conducted as an experimental baseline to assess the advantages of low-salinity waterflooding over typical secondary recovery methods. Effluent analysis was conducted to evaluate the surface interactions occurring between the brine and rock surface. Gas chromatography-mass spectroscopy was performed to compare the chemical make-up of the synthetic and crude oil. Oil recovery curves from this study indicate that there was no benefit after increasing the concentration of PDIs in injection water compared to seawater (SW). However, the use of seawater and all chemically tuned brines derived from seawater resulted in an average 6.47% increase in oil recovery post water breakthrough, relative to the formation brine waterflood. The success of wettability alteration leading to improved oil recovery in carbonates has been noted as a strong function of the oil composition.
Download or read book Waterflooding written by G. Paul Willhite and published by . This book was released on 1986 with total page 358 pages. Available in PDF, EPUB and Kindle. Book excerpt: Waterflooding begins with understanding the basic principles of immiscible displacement, then presents a systematic procedure for designing a waterflood.
Book Synopsis An experimental and numerical study of low salinity effects on the oil recovery of carbonate limestone samples by : Felix Feldmann
Download or read book An experimental and numerical study of low salinity effects on the oil recovery of carbonate limestone samples written by Felix Feldmann and published by Cuvillier Verlag. This book was released on 2020-03-02 with total page 254 pages. Available in PDF, EPUB and Kindle. Book excerpt: Low-salinity waterflooding is a relatively simple and cheap Enhanced oil recovery technique in which the salinity of the injected water is optimized (by desalination and/or modification) to improve oil recovery over conventional waterflooding. The presented study combines spontaneous imbibition, centrifuge method, unsteady state coreflooding and zeta potential experiments to investigate low-salinity effects in carbonate limestones samples. Compared to Formation-water and Sea-water, Diluted-sea-water caused the significantly highest spontaneous oil recovery. Moreover, the imbibition capillary pressure curves are characterized by an increasing water-wetting tendency and a residual oil saturation reduction, as the salinity of the imbibing brines decreases in comparison to Formation-water. The unsteady state corefloodings resulted in the highest secondary oil recovery when Diluted-sea-water was used as injection water. Based on the open-source C++ simulator Dumux, the study developed a numerical centrifuge and coreflooding model to history match the experimental data. The numerically derived capillary pressure and relative permeability data confirm a correlation between the system’s salinity, wettability, oil recovery and residual oil saturation.
Book Synopsis Asphaltene Deposition by : Francisco M. Vargas
Download or read book Asphaltene Deposition written by Francisco M. Vargas and published by CRC Press. This book was released on 2018-05-16 with total page 360 pages. Available in PDF, EPUB and Kindle. Book excerpt: As global consumption of fossil fuels such as oil increases, previously abundant sources have become depleted or plagued with obstructions. Asphaltene deposition is one of such obstructions which can significantly decrease the rate of oil production. This book offers concise yet thorough coverage of the complex problem of asphaltene precipitation and deposition in oil production. It covers fundamentals of chemistry, stabilization theories and mechanistic approaches of asphaltene behavior at high temperature and pressure. Asphaltene Deposition: Fundamentals, Prediction, Prevention, and Remediation explains techniques for experimental determination of asphaltene precipitation and deposition and different modeling tools available to forecast the occurrence and magnitude of asphaltene deposition in a given oil field. It discusses strategies for mitigation of asphaltene deposition using chemical inhibition and corresponding challenges, best practices for asphaltene remediation, current research, and case studies.
Book Synopsis Reservoir Engineering Handbook by : Tarek H. Ahmed
Download or read book Reservoir Engineering Handbook written by Tarek H. Ahmed and published by Gulf Professional Publishing. This book was released on 2001 with total page 1212 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book wxplains the fundamentals of reservoir engineering and their practical application in conducting a comprehensive field study.Two new chapters have been included in this second edition: chapter 14 and 15.
Book Synopsis Chemical Enhanced Oil Recovery by : Patrizio Raffa
Download or read book Chemical Enhanced Oil Recovery written by Patrizio Raffa and published by Walter de Gruyter GmbH & Co KG. This book was released on 2019-07-22 with total page 277 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book aims at presenting, describing, and summarizing the latest advances in polymer flooding regarding the chemical synthesis of the EOR agents and the numerical simulation of compositional models in porous media, including a description of the possible applications of nanotechnology acting as a booster of traditional chemical EOR processes. A large part of the world economy depends nowadays on non-renewable energy sources, most of them of fossil origin. Though the search for and the development of newer, greener, and more sustainable sources have been going on for the last decades, humanity is still fossil-fuel dependent. Primary and secondary oil recovery techniques merely produce up to a half of the Original Oil In Place. Enhanced Oil Recovery (EOR) processes are aimed at further increasing this value. Among these, chemical EOR techniques (including polymer flooding) present a great potential in low- and medium-viscosity oilfields. • Describes recent advances in chemical enhanced oil recovery. • Contains detailed description of polymer flooding and nanotechnology as promising boosting tools for EOR. • Includes both experimental and theoretical studies. About the Authors Patrizio Raffa is Assistant Professor at the University of Groningen. He focuses on design and synthesis of new polymeric materials optimized for industrial applications such as EOR, coatings and smart materials. He (co)authored about 40 articles in peer reviewed journals. Pablo Druetta works as lecturer at the University of Groningen (RUG) and as engineering consultant. He received his Ph.D. from RUG in 2018 and has been teaching at a graduate level for 15 years. His research focus lies on computational fluid dynamics (CFD).
Download or read book Core Analysis written by Colin McPhee and published by Elsevier. This book was released on 2015-12-10 with total page 853 pages. Available in PDF, EPUB and Kindle. Book excerpt: Core Analysis: A Best Practice Guide is a practical guide to the design of core analysis programs. Written to address the need for an updated set of recommended practices covering special core analysis and geomechanics tests, the book also provides unique insights into data quality control diagnosis and data utilization in reservoir models. The book's best practices and procedures benefit petrophysicists, geoscientists, reservoir engineers, and production engineers, who will find useful information on core data in reservoir static and dynamic models. It provides a solid understanding of the core analysis procedures and methods used by commercial laboratories, the details of lab data reporting required to create quality control tests, and the diagnostic plots and protocols that can be used to identify suspect or erroneous data. Provides a practical overview of core analysis, from coring at the well site to laboratory data acquisition and interpretation Defines current best practice in core analysis preparation and test procedures, and the diagnostic tools used to quality control core data Provides essential information on design of core analysis programs and to judge the quality and reliability of core analysis data ultimately used in reservoir evaluation Of specific interest to those working in core analysis, porosity, relative permeability, and geomechanics
Book Synopsis Enhanced Oil Recovery Field Case Studies by : James J.Sheng
Download or read book Enhanced Oil Recovery Field Case Studies written by James J.Sheng and published by Gulf Professional Publishing. This book was released on 2013-04-10 with total page 710 pages. Available in PDF, EPUB and Kindle. Book excerpt: Enhanced Oil Recovery Field Case Studies bridges the gap between theory and practice in a range of real-world EOR settings. Areas covered include steam and polymer flooding, use of foam, in situ combustion, microorganisms, "smart water"-based EOR in carbonates and sandstones, and many more. Oil industry professionals know that the key to a successful enhanced oil recovery project lies in anticipating the differences between plans and the realities found in the field. This book aids that effort, providing valuable case studies from more than 250 EOR pilot and field applications in a variety of oil fields. The case studies cover practical problems, underlying theoretical and modeling methods, operational parameters, solutions and sensitivity studies, and performance optimization strategies, benefitting academicians and oil company practitioners alike. Strikes an ideal balance between theory and practice Focuses on practical problems, underlying theoretical and modeling methods, and operational parameters Designed for technical professionals, covering the fundamental as well as the advanced aspects of EOR
Book Synopsis Enhanced Oil Recovery Processes by : Ariffin Samsuri
Download or read book Enhanced Oil Recovery Processes written by Ariffin Samsuri and published by BoD – Books on Demand. This book was released on 2019-12-18 with total page 162 pages. Available in PDF, EPUB and Kindle. Book excerpt: Concerned with production decline, shortages of new oil reserves, and increasing world energy demand, the oil sector continues to search for economic and efficient techniques to enhance their oil recovery from the existing oil field using several enhanced oil recovery techniques (EOR)methods. Despite its highefficiency, widely acclaimed potentials, and limitations, the Low Salinity Water Flooding (LSWF), hybrid, and nanotechnology applications have gained vast interest with promising future to increase ultimate oil recovery, tackle operational challenges, reduce environmental damage, and allow the highest feasible recoveries with lower production costs. This synergistic combination has opened new routes for novel materials with fascinating properties. This book aims to provide an overview of EOR technology such as LSWF, hybrid, and nanotechnology applications in EOR processes.
Author :Abdolhossein Hemmati-Sarapardeh Publisher :Gulf Professional Publishing ISBN 13 :0128219327 Total Pages :510 pages Book Rating :4.1/5 (282 download)
Book Synopsis Chemical Methods by : Abdolhossein Hemmati-Sarapardeh
Download or read book Chemical Methods written by Abdolhossein Hemmati-Sarapardeh and published by Gulf Professional Publishing. This book was released on 2021-11-30 with total page 510 pages. Available in PDF, EPUB and Kindle. Book excerpt: Chemical Methods, a new release in the Enhanced Oil Recovery series, helps engineers focus on the latest developments in one fast-growing area. Different techniques are described in addition to the latest technologies in data mining and hybrid processes. Beginning with an introduction to chemical concepts and polymer flooding, the book then focuses on more complex content, guiding readers into newer topics involving smart water injection and ionic liquids for EOR. Supported field case studies illustrate a bridge between research and practical application, thus making the book useful for academics and practicing engineers. This series delivers a multi-volume approach that addresses the latest research on various types of EOR. Supported by a full spectrum of contributors, this book gives petroleum engineers and researchers the latest developments and field applications to drive innovation for the future of energy. Presents the latest research and practical applications specific to chemical enhanced oil recovery methods Helps users understand new research on available technology, including chemical flooding specific to unconventional reservoirs and hybrid chemical options Includes additional methods, such as data mining applications and economic and environmental considerations
Book Synopsis Laboratory Investigation of Mechanisms Governing Low-salinity Waterflooding in Oil-wet Carbonate Reservoirs by : Gregory Kojadinovich
Download or read book Laboratory Investigation of Mechanisms Governing Low-salinity Waterflooding in Oil-wet Carbonate Reservoirs written by Gregory Kojadinovich and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Improved oil recovery via wettability alteration by tuning the ionic composition of the injection water has been thoroughly researched in recent years. It has been well documented that seawater can increase the water wetness of chalk at high temperature. Forced displacement and spontaneous imbibition experiments have attributed the wettability alteration to interactions between active ions in the brine, Ca2+, Mg2+, and SO42-, the rock surface, and the oil phase. It has been suggested that the adsorption of SO42- onto the rock surface causes the bond between adsorbed carboxylic material in the crude oil and the rock surface to deteriorate which causes the release of the crude oil. Reduction in ionic strength of the injection water has also been proposed to trigger the effect of wettability alteration in carbonates. Although the numerous experiments devoted to understanding the mechanisms governing the low salinity effect in the past two decades, there has been no consensus about the dominant mechanisms driving wettability alteration. The purpose of this research is to improve the understanding of how reduced ionic strength and potentially determining ions (PDIs) contribute to oil recovery, as well as provide a direct comparison of their oil recovery performance for a synthetic oil versus crude oil during waterflooding. For this, a series of waterflood experiments were conducted in the laboratory at 90 C in Indiana limestone core plugs. Chemically tuned brines derived from seawater were used in secondary and tertiary recovery modes to displace synthetic oil. A waterflood with formation brine was also conducted as an experimental baseline to assess the advantages of low-salinity waterflooding over typical secondary recovery methods. Effluent analysis was conducted to evaluate the surface interactions occurring between the brine and rock surface. Gas chromatography-mass spectroscopy was performed to compare the chemical make-up of the synthetic and crude oil. Oil recovery curves from this study indicate that there was no benefit afterincreasing the concentration of PDIs in injection water compared to seawater (SW). However, the use of seawater and all chemically tuned brines derived from seawater resulted in an average 6.47% increase in oil recovery post water breakthrough, relative to the formation brine waterflood. The success of wettability alteration leading to improved oil recovery in carbonates has been noted as a strong function of the oil composition.
Book Synopsis A Mechanism of Improved Oil Recovery by Low-Salinity Waterflooding in Sandstone Rock by : Ramez Masoud Azmy Nasralla
Download or read book A Mechanism of Improved Oil Recovery by Low-Salinity Waterflooding in Sandstone Rock written by Ramez Masoud Azmy Nasralla and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Injection of low-salinity water showed high potentials in improving oil recovery when compared to high-salinity water. However, the optimum water salinity and conditions are uncertain, due to the lack of understanding the mechanisms of fluid-rock interactions. The main objective of this study is to examine the potential and efficiency of low-salinity water in secondary and tertiary oil recovery for sandstone reservoirs. Similarly, this study aims to help in understanding the dominant mechanisms that aid in improving oil recovery by low-salinity waterflooding. Furthermore, the impact of cation type in injected brines on oil recovery was investigated. Coreflood experiments were conducted to determine the effect of water salinity and chemistry on oil recovery in the secondary and tertiary modes. The contact angle technique was used to study the impact of water salinity and composition on rock wettability. Moreover, the zeta potential at oil/brine and brine/rock interfaces was measured to explain the mechanism causing rock wettability alteration and improving oil recovery. Deionized water and different brines (from 500 to 174,000 mg/l), as well as single cation solutions were tested. Two types of crude oil with different properties and composition were used. Berea sandstone cores were utilized in the coreflood experiments. Coreflood tests indicated that injection of deionized water in the secondary mode resulted in significant oil recovery, up to 22% improvement, compared to seawater flooding. However, no more oil was recovered in the tertiary mode. In addition, injection of NaCl solution increased the oil recovery compared to injection of CaCl2 or MgCl2 at the same concentration. Contact angle results demonstrated that low-salinity water has an impact on the rock wettability; the more reduction in water salinity, the more a water-wet rock surface is produced. In addition, NaCl solutions made the rock more water-wet compared to CaCl2 or MgCl2 at the same concentration. Low-salinity water and NaCl solutions showed a highly negative charge at rock/brine and oil/brine interfaces by zeta potential measurements, which results in greater repulsive forces between the oil and rock surface. This leads to double-layer expansion and water-wet systems. These results demonstrate that the double-layer expansion is a primary mechanism of improving oil recovery when water chemical composition is manipulated. The electronic version of this dissertation is accessible from http://hdl.handle.net/1969.1/149468
