Wireline Formation Testing For Low Permeability Formations

Traditional well logging methods, such as resistivity, acoustic, nuclear and NMR, provide indirect information related to fluid and formation properties. 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, however, are shrouded in secrecy. Unfortunately, many are poorly constructed, and because details are not available, industry researchers are not able to improve upon them. This new book explains conventional models and develops new powerful algorithms for “double-drawdown” and “advanced phase delay” early-time analysis - importantly, it is now possible to predict both horizontal and vertical permeabilities, plus pore pressure, within seconds of well logging in very low mobility reservoirs. Other subjects including inertial Forchheimer effects in contamination modeling and time-dependent flowline volumes are also developed. All of the methods are explained in complete detail. Equations are offered for users to incorporate in their own models, but convenient, easy-to-use software is available for those needing immediate answers. The leading 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 United States Department of Energy. His new collaboration with China National Offshore Oil Corporation marks an important turning point, where advanced simulation models and hardware are evolving side-by-side to define a new generation of formation testing logging instruments. The present book provides more than formulations and solutions: it offers a close look at formation tester development “behind the scenes,” as the China National Offshore Oil Corporation opens up its research, engineering and manufacturing facilities through a collection of interesting photographs to show how formation testing tools are developed from start to finish.

Mysterious "supercharge effects," encountered in formation testing pressure transient analysis, and reservoir invasion, mudcake growth, dynamic filtration, stuck-pipe remediation, and so on, are often discussed in contrasting petrophysical versus drilling contexts. However, these effects are physically coupled and intricately related. The authors focus on a comprehensive formulation, provide solutions for different specialized limits, and develop applications that illustrate how the central ideas can be used in seemingly unrelated disciplines. This approach contributes to a firm understanding of logging and drilling principles. Fortran source code, furnished where applicable, is listed together with recently developed software applications and conveniently summarized throughout the book. In addition, common (incorrect) methods used in the industry are re-analyzed and replaced with more accurate models, which are then used to address challenging field objectives. Sophisticated mathematics is explained in "down to earth" terms, but empirical validations, in this case through Catscan experiments, are used to "keep predictions honest." Similarly, early-time, low mobility, permeability prediction models used in formation testing, several invented by one of the authors, are extended to handle supercharge effects in overbalanced drilling and near-well pressure deficits encountered in underbalanced drilling. These methods are also motivated by reality. For instance, overpressures of 2,000 psi and underpressures near 500 psi are routinely reported in field work, thus imparting a special significance to the methods reported in the book. This new volume discusses old problems and modern challenges, formulates and develops advanced models applicable to both drilling and petrophysical objectives. The presentation focuses on central unifying physical models which are carefully formulated and mathematically solved. The wealth of applications examples and supporting software discussed provides readers with a unified focus behind daily work activities, emphasizing common features and themes rather than unrelated methods and work flows. This comprehensive book is "must" reading for every petroleum engineer.

Wilson C. Chin has written some of the most important and well-known books in the petroleum industry. These books, whose research was funded by the U.S. Department of Energy and several international petroleum corporations, have set very high standards. Many algorithms are used at leading oil service companies to support key drilling and well logging applications. For the first time, the physical models in these publications, founded on rigorous mathematics and numerical methods, are now available to the broader industry: students, petroleum engineers, drillers and faculty researchers. The presentations are written in easy-to-understand language, with few equations, offering simplified explanations of difficult problems and solutions which provide key insights into downhole physical phenomena through detailed tabulations and color graphics displays. Practical applications, such as cuttings transport, pressure control, mudcake integrity, formation effects in unconventional applications, and so on, are addressed in great detail, offering the most practical answers to everyday problems that the engineer encounters. The book does not stop at annular flow. In fact, the important role of mudcake growth and thickness in enabling steady flow in the annulus is considered, as is the role of (low) formation permeability in affecting mud filtration, cake growth, and fluid sealing at the sandface. This is the first publication addressing “the big picture,” a “first” drawn from the author’s related research in multiple disciplines such as drilling rheology, formation testing and reservoir simulation. A must-have for any petroleum engineer, petroleum professional, or student, this book is truly a groundbreaking volume that is sure to set new standards for the industry.

A popular 1990s formation tester with a single "pumping" probe and one passive "observation port" displaced 180 deg away, designed to measure pressures at two locations for permeability prediction, encounters well known detection problems at low mobilities. This book, using aerodynamics methods, explains why and also reveals the existence of a wide stagnation zone that hides critical formation details. And it does much more. An exact analytical solution is used to validate a new transient, three-dimensional, finite difference model for more general testers, one that guides new hardware designs with independent azimuthally displaced probes having with different rates, flow schedules and nozzle geometries, supports interpretation and formation evaluation, and assists with job planning at the rigsite. The methods also apply to conventional tools, allowing comparisons between older and newer technologies. Importantly, the authors introduce a completely new three-probe design with independently operable active elements that eliminate all older tool deficiencies. Numerous subjects are discussed, such as pressure transient analyses with multiple operating probes, supercharge analysis with invasion and mudcake buildup, accurate and rapid calculations that allow more than 1,000 simulations per minute, extremely rapid batch mode calculations using convergence acceleration methods, rapid fluid withdrawal with minimal dissolved gas release, dip angle, heterogeneity and anisotropy evaluation, and many other topics. In addition, tool operation sequences, detailed engineering and design functions, field test procedures and laboratory facilities, are discussed and illustrated in photographs that go "behind the scenes" at one of the world’s largest international oil service companies. The book hopes to educate new engineers and veteran engineers alike in hardware and software design at a time when increasing efficiency is crucial and "doing more with less" represents the new norm.

Multiprobe Pressure Testing and Reservoir Characterization: Pressure Transient, Contamination, Liquid and Gas Pumping Analysis provides much-needed three-dimensional pressure transient simulators for job planning and data interpretation in well logging. First, discussions on fundamental concepts present fluid sampling, pressure transient and contamination analysis; physical concepts and numerical approaches; and multiprobe model formulations and validations. Other sections cover four-probe algorithms, including conventional, overbalanced, and underbalanced drilling applications. The final section addresses triple-probe algorithms, which includes coupled models for pressure and contamination convergence acceleration. Notably, Chapter 10 explains how the multiprobe tool’s focus on characterizing permeability will promote better use of the reservoir as well as assist with energy storage in underground rock, demonstrating how multiprobe tools also facilitate the energy transition from fossil fuels to sustainable geothermal energy. The book's mathematical methods are described in a straightforward manner with numerous example calculations and applications demonstrating the practical utility of the approaches. This book is an invaluable reference for petroleum geologists and engineers involved in geothermal and conventional reservoir characterization and simulation. Reviews present day needs, tool operations, and analysis methods, along with numerous practical examples and applications Develops a suite of mathematical models, algorithms, and software from first principles Explains, in detail, how multiprobe pressure logging is superior to using conventional sensors because direct, accurate reservoir characteristics support energy-efficient geothermal designs Provides an alternative look at the investigation of unconventional reservoirs, not only in terms of hydrocarbon production but also with carbon and energy storage in mind