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.

Unconventional Reservoir Rate-Transient Analysis provides petroleum engineers and geoscientists with the first comprehensive review of rate-transient analysis (RTA) methods as applied to unconventional reservoirs. Volume One—Fundamentals, Analysis Methods, and Workflow is comprised of five chapters which address key concepts and analysis methods used in RTA. This volume overviews the fundamentals of RTA, as applied to low-permeability oil and gas reservoirs exhibiting simple reservoir and fluid characteristics.Volume Two—Application to Complex Reservoirs, Exploration and Development is comprised of four chapters that demonstrate how RTA can be applied to coalbed methane reservoirs, shale gas reservoirs, and low-permeability/shale reservoirs exhibiting complex behavior such as multiphase flow. Use of RTA to assist exploration and development programs in unconventional reservoirs is also demonstrated. This book will serve as a critical guide for students, academics, and industry professionals interested in applying RTA methods to unconventional reservoirs. - Gain a comprehensive review of key concepts and analysis methods used in modern rate-transient analysis (RTA) as applied to low-permeability ("tight") oil and gas reservoirs - Improve your RTA methods by providing reservoir/hydraulic fracture properties and hydrocarbon-in-place estimates for unconventional gas and light oil reservoirs exhibiting complex reservoir behaviors - Understand the provision of a workflow for confident application of RTA to unconventional reservoirs

Pressure Transient Testing presents the fundamentals of pressure-transient test analysis and design in clear, simple language and explains the theoretical bases of commercial well-test-analysis software. Test-analysis techniques are illustrated with complete and clearly written examples. Additional exercises for classroom or individual practice are provided. With its focus on physical processes and mathematical interpretation, this book appeals to all levels of engineers who want to understand how modern approaches work. Pressure transient test analysis is a mature technology in petroleum engineering; even so, it continues to evolve. Because of the developments in this technology since the last SPE textbook devoted to transient testing was published, we concluded that students could benefit from a textbook approach to the subject that includes a representative sampling of the more important fundamentals and applications. We deliberately distinguish between a textbook approach, which stresses understanding through numerous examples and exercises dealing with selected fundamentals and applications, and a monograph approach, which attempts to summarize the state-of-the-art in the technology. Computational methods that transient test analysts use have gone through a revolution since most existing texts on the subject were written. Most calculations are now done with commercial software or by spreadsheets or proprietary software developed by users to meet personal needs and objectives. These advances in software have greatly increased productivity in this technology, but they also have contributed to a "black box" approach to test analysis. In this text, we attempt to explain what's in the box, and we do not include a number of the modern tools that enhance individual engineer productivity. We hope, instead, to provide understanding so that the student can use the commercial software with greater appreciation and so that the student can read monographs and papers on transient testing with greater appreciation for the context of the subject. Accordingly, this text is but an introduction to the vast field of pressure transient test analysis.

Pressure Transient Analysis: Pressure Derivative provides focuses on applications of pressure and derivative data for interpretation of pressure transient tests, offering alternatives to costly commercial software. Building from basics, this practical text spans: wells near single and multi-boundary systems, hydraulically fractured wells, naturally fractured reservoirs, interpretation of interference and pulse tests, gas well test analysis (including sources of emissions and decarbonizing strategies, geological sequestration, CCS risks and stress on CCS), multiphase flow, injectivity and falloff tests, rate transient and multi-rate tests, partially penetrated / perforated vertical and slanted wells, and horizontal wells in conventional and unconventional reservoirs.Many techniques and equations presented in this book can be found in the black box of commercial well-test analysis software packages – this practical text unlocks, unpacks, and makes critical, analytical tools accessible to core users. - Delivers an alternative technique to type-curve matching using the loglog analysis - Introduces simple analytical equations used in the step-by-step procedure for analyzing pressure transient tests - Presents common cases encountered by practicing engineers inspired by a robust literature review, boasting over 500 diverse, global sources - Includes (75) solved simulated exercises and field cases, along with (81) unsolved problems (simulated and field cases) to reinforce learning - Supports sustainability and the reduction of carbon emissions by addressing carbon footprints, emissions sources and decarbonizing strategies, carbon capture, storage, and CO2 storage

This reference presents a comprehensive description of flow through porous media and solutions to pressure diffusion problems in homogenous, layered, and heterogeneous reservoirs. It covers the fundamentals of interpretation techniques for formation tester pressure gradients, and pretests, multiprobe and packer pressure transient tests, including derivative, convolution, and pressure-rate and pressure-pressure deconvolution. Emphasis is placed on the maximum likelihood method that enables one to estimate error variances in pressure data along with the unknown formation parameters. - Serves as a training manual for geologists, petrophysicists, and reservoir engineers on formation and pressure transient testing - Offers interpretation techniques for immediate application in the field - Provides detailed coverage of pretests, multiprobe and packer pressure transient tests, including derivative, convolution, and pressure-rate and pressure-pressure deconvolution

Unconventional gas reservoirs, such as tight gas and shale gas, appear to have great potential to supply future demand for hydrocarbon. Economics of these reservoirs are tied closely to the performance of multi-fractured horizontal wells (MFHWs), which is the most direct indicator of stimulation effectiveness. Thus, greater understanding and analysis of the factors affecting performance of MFHWs are critical for the efficient exploitation of such reservoirs. Hydrocarbon production data analysis (PDA) techniques have been commonly used to characterize hydraulic fracture (HF) and, ultimately, to evaluate hydraulic-fracturing jobs. Recent studies have shown that rate transient analysis of flowback data can also provide early insight into HF attributes. While PDA methods seek long-time production data, flowback analysis can be conducted using early water and gas production data obtained immediately after the completion of stimulation jobs. However, in comparison with the long-term hydrocarbon production period, the physics of the process is more difficult to capture during flowback production because of its short duration, at which one or more flow regimes may occur. In addition, the flowback flow system could be single- or two-phase, depending on reservoir type. According to reported field data, single-phase flowback can be observed in tight sands, but two-phase flow is expected in the case of shale gas. Although various mathematical models have been proposed to analyze single-phase (water) and two-phase (gas and water) flowback data, analytical models for interpretation of data are still at an early stage of development. The objectives of this study are first to reproduce the relevant analytical models available in literature and understand their advantages and limitations; then, to develop single-phase and two-phase analytical models capable of predicting HF attributes such as fracture half-length and fracture permeability using early water and gas production data. In this study, a set of numerical simulations was conducted using CMG (IMEX) to examine the capacity of available mathematical models. It was found that most of the single-phase flowback models in the literature are accurate only under pseudo steady-state conditions, where a boundary-dominated flow regime with a constant production rate has been established. Another limitation of current models is that they can only estimate one fracture attributes: kf or xf. Knowing the shortcomings of current models, I developed a set of analytical models for both single- and two-phase systems, which were validated against numerical simulations. The single-phase model can closely estimate HF attributes, such as permeability and half-length under constant pressure as well as constant flowrate condition, for both transient and boundary dominated flow periods. Furthermore, I extended the developed single-phase model to variable bottomhole conditions by employing superposition principle. In the case of two-phase flow system, I developed an analytical model under fracture depletion mechanism for both early gas production (EGP) and late gas production (LGP) periods. In the case of EGP, gas flux from matrix to HF is assumed to be negligible. Comparisons of numerical results with those obtained from the analytical model show that the developed two-phase model for EGP can accurately predict fracture attributes. In the case of LGP, a coupled model is developed to include the effect of gas influx from matrix to HF on flowback data, where a uniform pressure decline rate is assumed in fracture-matrix system. The two-phase model has the advantage of linear behavior of water properties and avoids the computational complexity. With typical Barnett shale properties input in the numerical simulation, the analytical model can accurately estimate fracture attributes within a 10% error margin. Sensitivity analyses of fracture conductivity and initial water saturation in fracture have been conducted to illustrate the validity of two-phase flowback model applied in LGP. The results reveal that, within the physical range of fracture conductivity and initial water saturation, the two-phase flowback model can accurately evaluate fracture attributes. However, the model is more accurate for cases with smaller fracture conductivity and higher initial water saturation in fracture.

The only book available for the reservoir or petroleum engineer covering formation testing—with algorithms for wireline and LWD reservoir analysis developed for transient pressure, contamination modeling, permeability, and pore pressure prediction. Traditional well logging methods, such as resistivity, acoustic, nuclear, and NMR, provide indirect information relating to fluid and formation properties. However, the "formation tester" offered in wireline and MWD/LWD operations is different. It collects actual downhole fluid samples for surface analysis, and through pressure transient analysis, provides direct measurements for pore pressure, mobility, permeability, and anisotropy. These are vital to real-time drilling safety, geosteering, hydraulic fracturing, and economic analysis. Methods for formation testing analysis, while commercially important and accounting for a substantial part of service company profits, are shrouded in secrecy. Many are poorly constructed, and because details are not available, industry researchers are not able to improve on them. Formation Testing explains conventional models and develops new, more powerful algorithms for early-time analysis. More importantly, it addresses a critical area in sampling related to "time required to pump clean samples," using rigorous multiphase flow techniques. All of the methods are explained in complete detail. Equations are offered for users to incorporate in their own models, but, for those needing immediate answers, convenient, easy-to-use software is available. The lead author is a well-known petrophysicist with hands-on experience at Schlumberger, Halliburton, BP Exploration, and other companies. His work is used commercially at major oil service companies, and important extensions to his formation testing models have been supported by prestigious grants from the U.S. Department of Energy. His latest collaboration with China National Offshore Oil Corporation marks an important turning point, where advanced simulation models and hardware are evolving side-by-side, defining a new generation of formation testing logging instruments. Providing more than formulations and solutions, this book offers a close look at "behind the scenes" formation tester development, as the China National Offshore Oil Corporation opens up its research, engineering, and manufacturing facilities through a collection of never-before-seen photographs, showing how formation testing tools are developed from start to finish.

This book deals exclusively with naturally fractured reservoirs and includes many subjects usually treated in separate volumes. A highly practical edition, Naturally Fractured Reservoirs is written for students, reservoir geologists, log analysts and petroleum engineers.