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Recent Advances In Reservoir Stimulation And Eor Technology In Unconventional Reservoirs
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Book Synopsis Recent Advances in Reservoir Stimulation and EOR Technology in Unconventional Reservoirs by : Lufeng Zhang
Download or read book Recent Advances in Reservoir Stimulation and EOR Technology in Unconventional Reservoirs written by Lufeng Zhang and published by . This book was released on 2024-02-09 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the past decade, the rapid increase in the production of fossil energy has been made possible by effective reservoir stimulation and enhanced oil recovery (EOR) technologies for unconventional oil and gas reservoirs. As one of the most important reservoir stimulation technologies, hydraulic fracturing aims to increase the contact area between the target formation and production well. Such stimulation technologies usually involve complex fluid-solid coupling processes, including fracture initiation, fracture propagation, and fracture conductivity, etc. Enhanced oil recovery has been used to solve the problem of oil rate declining sharply after a period of production. In this process, some special chemicals will be injected into the reservoir to increase the recovery effectiveness of the residual oil. EOR processes often involve complex physical-chemical processes, including liquid emulsification, water-rock reactions, etc. Therefore, the progress of reservoir stimulation and EOR technology will contribute to the rapid development of unconventional oil and gas resources. Meanwhile, these technologies are also used in the development of geothermal and coal resources.
Book Synopsis Fundamentals of Enhanced Oil Recovery Methods for Unconventional Oil Reservoirs by : Dheiaa Alfarge
Download or read book Fundamentals of Enhanced Oil Recovery Methods for Unconventional Oil Reservoirs written by Dheiaa Alfarge and published by Elsevier. This book was released on 2020-09-09 with total page 288 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fundamentals of Enhanced Oil Recovery Methods for Unconventional Oil Reservoirs, Volume 67 provides important guidance on which EOR methods work in shale and tight oil reservoirs. This book helps readers learn the main fluid and rock properties of shale and tight reservoirs—which are the main target for EOR techniques—and understand the physical and chemical mechanisms for the injected EOR fluids to enhance oil recovery in shale and tight oil reservoirs. The book explains the effects of complex hydraulic fractures and natural fractures on the performance of each EOR technique. The book describes the parameters affecting obtained oil recovery by injecting different EOR methods in both the microscopic and macroscopic levels of ULR. This book also provides proxy models to associate the functionality of the improved oil recovery by injecting different EOR methods with different operating parameters, rock, and fluid properties. The book provides profesasionals working in the petroleum industry the know-how to conduct a successful project for different EOR methods in shale plays, while it also helps academics and students in understanding the basics and principles that make the performance of EOR methods so different in conventional reservoirs and unconventional formations. Provides a general workflow for how to conduct a successful project for different EOR methods in these shale plays Provides general guidelines for how to select the best EOR method according to the reservoir characteristics and wells stimulation criteria Explains the basics and principles that make the performance of EOR methods so different in conventional reservoirs versus unconventional formations
Book Synopsis Phase Behavior and Compositional Simulation of Solvent EOR Processes in Unconventional Reservoirs by : Sajjad Sadeghi Neshat
Download or read book Phase Behavior and Compositional Simulation of Solvent EOR Processes in Unconventional Reservoirs written by Sajjad Sadeghi Neshat and published by . This book was released on 2020 with total page 488 pages. Available in PDF, EPUB and Kindle. Book excerpt: Recent advances in hydraulic fracturing and horizontal drilling technologies applied to unconventional resources have enabled very large increases in oil and gas production in the United States. While the initial production rate from new wells is often high, the rate of decline during the first year of production is also very high. The ultimate hydrocarbon recovery using current technology is estimated to be between 5 to 10%, which is very low compared to conventional oil reservoirs. These challenges have increased the demand for enhanced oil recovery (EOR) in unconventional reservoirs. Unconventional reservoirs have very different properties than conventional reservoirs such as extremely low permeability, wide and complex pore size distributions, high total organic carbon (TOC), and high heterogeneity. New cost effective EOR methods consistent with these properties are needed. This research presents a new framework for phase behavior modeling and compositional simulation of solvent EOR in unconventional reservoirs (also called tight oil reservoirs). Several new physical models were developed for this purpose. The new developments include a three-phase capillary pressure model, a phase stability method for multi-component mixtures with capillary pressure, coupled three-phase flash and capillary pressure models, and a new oil characterization method for organic-rich reservoirs. These models improve petrophysical, thermodynamic, and transport modeling of unconventional reservoirs. All new models were implemented in UTCOMP, an equation-of-state compositional reservoir simulator. The simulator was used for design and optimization of solvent EOR processes in organic-rich tight oil reservoirs. The oil recovery using cyclic huff-n-puff injection of a variety of solvents such as natural gas, CO2, methanol and dimethyl ether (DME) was compared. DME has the best performance among all solvents considered in this research. At reservoir conditions, DME mixes with both water and hydrocarbon phases. This helps to remove water blockage as well as retrograde condensate in gas-condensate reservoirs. DME can also extract part of the bitumen in the rock, which does not flow by itself due to its extremely high viscosity. Since the recovery rate of DME is very high, it can be recycled and injected back into the reservoir to reduce its net cost
Book Synopsis Fundamentals of Enhanced Oil and Gas Recovery from Conventional and Unconventional Reservoirs by : Alireza Bahadori
Download or read book Fundamentals of Enhanced Oil and Gas Recovery from Conventional and Unconventional Reservoirs written by Alireza Bahadori and published by Gulf Professional Publishing. This book was released on 2018-08-18 with total page 536 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fundamentals of Enhanced Oil and Gas Recovery from Conventional and Unconventional Reservoirs delivers the proper foundation on all types of currently utilized and upcoming enhanced oil recovery, including methods used in emerging unconventional reservoirs. Going beyond traditional secondary methods, this reference includes advanced water-based EOR methods which are becoming more popular due to CO2 injection methods used in EOR and methods specific to target shale oil and gas activity. Rounding out with a chapter devoted to optimizing the application and economy of EOR methods, the book brings reservoir and petroleum engineers up-to-speed on the latest studies to apply. Enhanced oil recovery continues to grow in technology, and with ongoing unconventional reservoir activity underway, enhanced oil recovery methods of many kinds will continue to gain in studies and scientific advancements. Reservoir engineers currently have multiple outlets to gain knowledge and are in need of one product go-to reference. Explains enhanced oil recovery methods, focusing specifically on those used for unconventional reservoirs Includes real-world case studies and examples to further illustrate points Creates a practical and theoretical foundation with multiple contributors from various backgrounds Includes a full range of the latest and future methods for enhanced oil recovery, including chemical, waterflooding, CO2 injection and thermal
Book Synopsis Reservoir Stimulation by : Michael J. Economides
Download or read book Reservoir Stimulation written by Michael J. Economides and published by . This book was released on 2000-06-23 with total page 932 pages. Available in PDF, EPUB and Kindle. Book excerpt: Sets forth a rationalisation of stimulation using reservoir engineering concepts, and addresses topics such as formation characterisation, hydraulic fracturing and matrix acidizing. Formation damage, which refers to a loss in reservoir productivity, is also examined comprehensively.
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).
Book Synopsis Unconventional Reservoirs: Rate and Pressure Transient Analysis Techniques by : Amin Taghavinejad
Download or read book Unconventional Reservoirs: Rate and Pressure Transient Analysis Techniques written by Amin Taghavinejad and published by Springer Nature. This book was released on 2021-09-13 with total page 119 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides a succinct overview on the application of rate and pressure transient analysis in unconventional petroleum reservoirs. It begins by introducing unconventional reservoirs, including production challenges, and continues to explore the potential benefits of rate and pressure analysis methods. Rate transient analysis (RTA) and pressure transient analysis (PTA) are techniques for evaluating petroleum reservoir properties such as permeability, original hydrocarbon in-place, and hydrocarbon recovery using dynamic data. The brief introduces, describes and classifies both techniques, focusing on the application to shale and tight reservoirs. Authors have used illustrations, schematic views, and mathematical formulations and code programs to clearly explain application of RTA and PTA in complex petroleum systems. This brief is of an interest to academics, reservoir engineers and graduate students.
Book Synopsis Reservoir Stimulation by : Michael J. Economides
Download or read book Reservoir Stimulation written by Michael J. Economides and published by . This book was released on 1987 with total page 300 pages. Available in PDF, EPUB and Kindle. Book excerpt: More than 13 years ago, the first edition of Reservoir Stimulation was published. The second edition followed in 1989 and contained substantial additions, updates and two new chapters. Planning for the third edition began in October 1994 in response to the demand for an updated version of the book. This new edition has been completely rewritten to reflect the changing technologies in the industry and contains 20 chapters written by 44 authors. It continues to provide an overview of reservoir stimulation from an all-encompassing engineering standpoint, an overview currently unavailable elsewhere. Reservoir Stimulation sets forth a rationalisation of stimulation using reservoir engineering concepts, and addresses topics such as formation characterisation, hydraulic fracturing and matrix acidizing. Formation damage, which refers to a loss in reservoir productivity, is also examined comprehensively. This extensive reference work remains essential reading for petroleum industry professionals involved in the important activities of reservoir evaluation, development and management, who require invaluable skills in the application of the techniques described for the successful exploitation of oil and gas reservoirs. Contributors to this volume are among the most recognized authorities in their individual technologies. The editors are grateful for their participation and thank clients, academic institutions and other organizations for supporting the completion of this text.
Book Synopsis Development of Unconventional Reservoirs by : Reza Rezaee
Download or read book Development of Unconventional Reservoirs written by Reza Rezaee and published by MDPI. This book was released on 2020-04-16 with total page 522 pages. Available in PDF, EPUB and Kindle. Book excerpt: The need for energy is increasing and but the production from conventional reservoirs is declining quickly. This requires an economically and technically feasible source of energy for the coming years. Among some alternative future energy solutions, the most reasonable source is from unconventional reservoirs. As the name “unconventional” implies, different and challenging approaches are required to characterize and develop these resources. This Special Issue covers some of the technical challenges for developing unconventional energy sources from shale gas/oil, tight gas sand, and coalbed methane.
Book Synopsis Advances in Enhancing Unconventional Oil/Gas Recovery by : Tao Zhang
Download or read book Advances in Enhancing Unconventional Oil/Gas Recovery written by Tao Zhang and published by . This book was released on 2024-07-31 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This reprint aims to immerse readers in the latest advances in enhancing unconventional oil and gas recovery, focusing on reservoirs such as tight gas/oil, shale gas/oil, and coalbed methane. The contributions include new laboratory measurements, simulation studies, mathematical modeling, and field case studies, spanning topics such as reservoir characterization, fluids in porous media, productivity evaluation, enhanced oil recovery (EOR)/enhanced gas recovery (EGR), and machine learning and data science. The studies presented here provide new insights into the complex dynamics of unconventional reservoirs and propose innovative solutions to the challenges they present. Together, we embark on a journey to unlock the full potential of unconventional reservoirs, seeking solutions that balance our growing energy needs with the responsibility to achieve carbon neutrality goals. This reprint serves as a testament to the remarkable progress in the field, paving the way for a greener, more sustainable future where energy resources are utilized efficiently and responsibly.
Book Synopsis Enhanced Oil Recovery in Shale and Tight Reservoirs by : James J.Sheng
Download or read book Enhanced Oil Recovery in Shale and Tight Reservoirs written by James J.Sheng and published by Gulf Professional Publishing. This book was released on 2019-11-07 with total page 538 pages. Available in PDF, EPUB and Kindle. Book excerpt: Oil Recovery in Shale and Tight Reservoirs delivers a current, state-of-the-art resource for engineers trying to manage unconventional hydrocarbon resources. Going beyond the traditional EOR methods, this book helps readers solve key challenges on the proper methods, technologies and options available. Engineers and researchers will find a systematic list of methods and applications, including gas and water injection, methods to improve liquid recovery, as well as spontaneous and forced imbibition. Rounding out with additional methods, such as air foam drive and energized fluids, this book gives engineers the knowledge they need to tackle the most complex oil and gas assets. Helps readers understand the methods and mechanisms for enhanced oil recovery technology, specifically for shale and tight oil reservoirs Includes available EOR methods, along with recent practical case studies that cover topics like fracturing fluid flow back Teaches additional methods, such as soaking after fracturing, thermal recovery and microbial EOR
Book Synopsis Unconventional Tight Reservoir Simulation: Theory, Technology and Practice by : Qiquan Ran
Download or read book Unconventional Tight Reservoir Simulation: Theory, Technology and Practice written by Qiquan Ran and published by Springer. This book was released on 2020-08-15 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book systematically introduces readers to the simulation theory and techniques of multiple media for unconventional tight reservoirs. It summarizes the macro/microscopic heterogeneities; the features of multiscale multiple media; the characteristics of complex fluid properties; the occurrence state of continental tight oil and gas reservoirs in China; and the complex flow characteristics and coupled production mechanism under unconventional development patterns. It also discusses the simulation theory of multiple media for unconventional tight oil and gas reservoirs; mathematic model of flow through discontinuous multiple media; geological modeling of discrete multiscale multiple media; and the simulation of multiscale, multiphase flow regimes and multiple media. In addition to the practical application of simulation and software for unconventional tight oil and gas, it also explores the development trends and prospects of simulation technology. The book is of interest to scientific researchers and technicians engaged in the development of oil and gas reservoirs, and serves as a reference resource for advanced graduate students in fields related to petroleum.
Book Synopsis Technology and Economics Affecting Unconventional Reservoir Development by : Cecilia P. Flores Campero
Download or read book Technology and Economics Affecting Unconventional Reservoir Development written by Cecilia P. Flores Campero and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Worldwide, unconventional resources are important sources of oil and gas when most conventional resources are declining and demand for hydrocarbons is growing. The Masters? (1979) concept of the energy resource triangle suggest that the exploitation of unconventional reservoirs is particularly sensitive to both technology and commodity price parameters. In the United States, production from unconventional reservoirs has been stimulated by a combination of Federal tax credits, technical development programs -supported by government agencies and private organizations- and high commodity prices. In this work, the effect of technology and different economic events for selected unconventional oil and gas plays in the United States was evaluated according to the concept of the Resource Triangle Theory (RTT). Studies conducted in the Austin Chalk -our textbook case- and other seven unconventional plays in the United States have supported the RTT concept that high prices and better technologies do result in more drilling activity and more oil and gas production from unconventional reservoirs. For instance, two approaches were employed to support RTT concept: Correlation study and Forecasting graphs. On the first one, correlations of commodity prices and technology with drilling activity demonstrated that periods of high commodity prices coincide with increase in unconventional producing wells approximately 75% from selected plays in this study. The second one shows that high prices and technological advances also translate into additional oil and gas production and reserves. This behavior was observed through the analysis of a series of decline production curves using a VBA program in Excel that compute oil and gas production volumes and their corresponding economic values under specific conditions. The results indicated that maximum value of approximately $50 billion oil plus gas would have been possible using conventional hydraulic fracturing technology only. Moreover, subsequent episodes of high commodity allow the introduction of new technologies that have boosted even more oil and gas production from the plays. Great examples are the use of horizontal and multilateral wells which has opened up additional areas for development, such as the Barnett Shale and the Bakken Shale. Using horizontal wells has also revived older plays, such as the Austin Chalk. The combination of horizontal well technology and water fracturing technology has led to a dramatic increase in the development of both oil and gas from shale reservoirs. Current production schemes suggest that the plays could produce an additional of $320 billion when producing at rates higher than 5 BOE/day. Our results confirm the concept of the resource triangle that natural gas and oil resources can be produced from low quality resources when either product prices increase or when better technology is available. The seven oil and gas plays studied in this research are demonstrative examples.
Book Synopsis Chemical Enhanced Oil Recovery (cEOR) by : Laura Romero-Zerón
Download or read book Chemical Enhanced Oil Recovery (cEOR) written by Laura Romero-Zerón and published by BoD – Books on Demand. This book was released on 2016-10-19 with total page 204 pages. Available in PDF, EPUB and Kindle. Book excerpt: Commercial application of chemical enhanced oil recovery (cEOR) processes is expected to grow significantly over the next decade. Thus, Chemical Enhanced Oil Recovery (cEOR): A Practical Overview offers key knowledge and understanding of cEOR processes using an evidence-based approach intended for a broad audience ranging from field operators, researchers, to reservoir engineers dealing with the development and planning of cEOR field applications. This book is structured into three sections; the first section surveys overall EOR processes. The second section focuses on cEOR processes, while the final section describes the electrorheology technology. These sections are presented using a practical and realistic approach tailored for readers looking to improve their knowledge and understanding of cEOR processes in a nutshell.
Book Synopsis Enhanced Oil Recovery (EOR) in Unconventional Reservoirs by : Adi Junira
Download or read book Enhanced Oil Recovery (EOR) in Unconventional Reservoirs written by Adi Junira and published by . This book was released on 2021 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Rapid production decline is typical in oil production from unconventional reservoirs. Enhanced oil recovery (EOR) with gas in cyclical (huff-n-puff) injection mode is arguably the most feasible method to solve the problem of relatively low oil recovery in the low permeability reservoirs, as supported by wealth of evidences. Nonetheless, the results so far seem vary widely. In some cases, the results are encouraging, while in some others, they are marginal. There seems to be many parameters to be considered in predicting the chance of a huff-n-puff gas EOR success. It is of interest not to just be able to forecast whether a huff-n-puff gas EOR will result in a satisfactory result, but also to obtain the highest oil recovery achievable, at least theoretically. With reliable real field data, rather than the synthetic one, research to identify the most significant factors affecting the gas EOR results in unconventional reservoirs by means of the widely used numerical simulation, is possible. The origin of the data should arguably give more credibility to the results, and thus their related analyses. Once the significant factors are identified and how they interact is understood, an optimum operational parameters design that maximizes the oil recovery is attainable. The acquired knowledge can also be of use in reducing the unknowns in other attempts with other methods to improve unconventional reservoirs’ oil recovery, so that the focus can be directed towards the right direction. Admittedly, uncertainties are inherent to the procedures used, but they are assumed to be acceptable for the purpose. This research found that the maximization of the oil recovery from unconventional reservoirs is viable and it is worth the resources spent. There seems to be some kind of matrix permeability threshold, below which the gas EOR will return meager even negative incremental oil recovery. This is because in order for the EOR to work well, the oil phase must be able to traverse with reasonable ease in the matrix, unless the injection gas effectively vaporizes the reservoir oil phase. Good injection gas choices are the ones that lower the oil viscosity while monotonically vaporize it in reservoir conditions. Field gas, [CO2, C2, C3, and C4] are usually good injection gas choices, with certain conditions. Single oil or gas phase in reservoir conditions is desirable, as the presence of another phase will adversely affect the phase flow, as described by the relative permeability curves concept. Good operational parameters are the ones that facilitate the production of the heavy components the most, while minimizing the obstruction to the oil influx from the matrix to the SRV. By extension, it is suggested that the use of water-based surfactant could be detrimental to the oil recovery in the long term, as the water phase will block the injection gas contact with the reservoir fluid. The inability to apply sufficiently high pressure without adversely affecting the aforementioned oil influx is a concerning challenge in the real field EOR implementation. Unless the reservoir permeability is enough to allow adequate oil phase mobility, it may be more reasonable to produce such unconventional reservoirs in primary production mode. Moreover, a higher GOR tends return a higher incremental oil recovery for black and volatile oil, in case of the EOR is applied from the beginning without a preceding primary production period. The data obtained from the oil-producing fields is also used to develop some kind of screening criteria for injection gas type, within which a huff-n-puff gas EOR will result in a good incremental oil recovery. The criteria cover the reservoir pressure, oil viscosity, C7+ molar fraction, and fracture conductivity. However, due to the available data is for reservoir oil with relatively low viscosity, the screening criteria is also more appropriate for such type of reservoir oil. As for the reservoir permeability point of view, the screening criteria is more suited for unconventional reservoirs with permeability of 685 nanodarcy or higher
Book Synopsis Investigative Study and Sensitivity Analysis of Thermal Stimulation in Unconventional Shale Reservoirs by : Nkemakonam Uzodimma Egboga
Download or read book Investigative Study and Sensitivity Analysis of Thermal Stimulation in Unconventional Shale Reservoirs written by Nkemakonam Uzodimma Egboga and published by . This book was released on 2016 with total page 220 pages. Available in PDF, EPUB and Kindle. Book excerpt: Shale oil production from plays such as the Bakken and Eagle Ford, driven by advances in horizontal well drilling and hydraulic fracturing technology, has helped improve US domestic oil production. However, due to the low permeability of shale oil reservoirs, primary depletion only produces 5 – 10% of the original oil in place and there is an enormous potential for improved recovery. Chemical and gas huff-and-puff methods have been piloted with varying degrees of success, but no breakthrough recovery method has been discovered. In this study, we examined improved oil recovery from shale reservoirs by thermal stimulation, consisting of primary depletion (early in a well’s life), followed by conversion of the well to a heat injector to elevate reservoir temperature, and finally a secondary depletion. A 2D black oil, thermal, reactive transport simulator was developed to test the viability of the proposed method and then CMG STARS, a more advanced compositional/thermal simulator, was used to investigate the mechanisms involved, as well as key parameters affecting recovery during thermal stimulation. We found that 1000 days of thermal stimulation with a 700 °F heater has the potential to increase economical oil recovery from about 7% to more than 11.5%, with potential for even greater recovery if heat injection time and temperature are optimized, as well as if heat is injected while producing oil from an adjacent well. Thermal pressurization of oil is the primary mechanism for the improved recovery. Kerogen decomposition into oil and gas results in a significant increase of hydrocarbons in place but is only a minor contribution to the additional recovery because production is limited by a lack of flow capacity. Furthermore, a two-fold increase in permeability is observed as a result of kerogen decomposition, but its contribution to recovery is also minor because the heated region is not well connected with the fractured region. The heating scheme may be improved in the future to better connect the heated region with the fractured region
Book Synopsis Production from Unconventional Petroleum Reservoirs by : Kenneth Imo-Imo Israel Eshiet
Download or read book Production from Unconventional Petroleum Reservoirs written by Kenneth Imo-Imo Israel Eshiet and published by . This book was released on 2018 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: An overview of the different categories of unconventional oil and gas reservoirs, and corresponding stimulation techniques appropriate for them is examined. Three main groups of unconventional oil and gas formations are appraised: heavy oil, oil shale and tight reservoirs. The scope of stimulation methods applicable to heavy oil reservoirs is limited. This kind of formation contains characteristic high-viscous hydrocarbons and are produced majorly by cold production and thermal stimulation. On the other hand, a wider range of stimulation methods are successfully used to produce tight and oil shales formations. For oil shales, these include drilling horizontal wells as substitutes to vertical wells, hydraulic fracturing, surfactant treatment, water imbibition, thermal treatment and acidisation; whilst for tight formations, these include hydraulic fracturing, surfactant treatment, water imbibition, acidisation and the application of electro-kinetics. Fracturing fluid systems are integral to the implementation of most stimulation operations and are evaluated herein under the following groups: water-based, oil-based, foam-based and acid-based. The most commonly used fracturing fluids are water based, albeit there are several instances where other types of fluids or combination of fluids are more suitable based on factors such as formation sensitivity, costs, wettability, rock solubility, surface tension, capillarity, viscosity, density, rheology and reactivity.
