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Induction logging
Book reviews papers on geochemical logging for elemental and mineral compositons of sandstones, mudrocks and igneous and metamorphic rocks. The feasibility of wireline geochemical characterization is demonstrated. Two other papers examine the relationship between nuclear log responses and mineralogy in North Sea reservoirs while a seventh is concerned with the identification of source rocks from logs. The identification of faults and fractures is addressed through five papers that collectively deal with the interpretation of dipmeter surveys, circumferential acoustic logs, formation microscanner images, sonic waveform logs and borehole televiewer images. One of these papers specifically deals with the North Sea chalk while another relates the occurrence of clay-filled fractures to permeability reduction inferred from packer tests in a North American indurated dolomite. The final theme of physical properties comprises two
papers on the determination of in situ stresses in sediments and basalts, one paper that deals with the electrical properties of basalts and the implications for pore geometry, and a fourth that evaluates Christensen's equation for the prediction of shear-wave velocity and engineering parameters. Overall, the collected papers constitute an interesting and varied representation of topical geological issues and how these are being addressed through down-hole measurements. The technical quality seems remarkably consistent for a multi-authored work. In view of its uniqueness, the book will attract a good deal of interest among those involved in the quantitative geological description of both sedimentary and basement rocks.
Paul Worthington BP Research, Sunbury, UK
Seismic Methods Michel Lavergne Editions Technip; 1989; Price: FF340; 192 pp Seismic Methods is a short book (173 pages, including the index and references) that covers all aspects of both seismic reflection and seismic refraction exploration techniques from the theory of propagation of seismic waves, through signal theory and data acquisition, to data processing. Perhaps inevitably, some aspects receive a more detailed treatment than others. The chapter on the propagation of seismic waves lays a solid detailed foundation for what follows. It gives a more detailed treatment than several much larger books on the seismic method and is clearly and concisely laid out. It starts from the stress and strain tensors and gives a short but thorough treatment of the main aspects of seismic wave propagation including the different forms of seismic wave, acoustic impedance, reflection and transmission at interfaces, propagation in homogenous and inhomogenous media and anelastic effects. In the chapter on seismic signals, difficulties arise because of the breadth of the subject that is covered in 23 pages, i.e. definition of signal and noise, seismic pulse, Fourier transform, convolution, cross and auto correlation, analytical signal and trace attributes, wave-number filters, synthetic seismograms, multiples, Vibroseis, vertical and horizontal resolution. The reader who already knows the subject in some depth will be able to use this chapter as a quick aide memoir on some points (the section on synthetic seismograms is probably the best part), but I wonder how easily someone studying the subject for the first time will manage the highly abbreviated presentation. The concept and use of the Fourier transform is very sparsely stated and no reference is given in the text to where a fuller and more explanatory treatment may be found, This is not helped by some errors, possibly of translation. For example, it is stated that Figure 3.3 shows examples of signals and their Fourier transforms, whereas what is actually shown are examples of signals and their amplitude and phase spectra. The book is more successful in giving an account of
the acquisition of seismic reflection data in Chapter 4, which reviews all the modern techniques including shear-wave surveys, although I do not understand why a section on the geometry of reflected rays and the definition of RMS velocity occurs in the middle of the chapter. A t the end of the chapter a somewhat uneven treatment of seismic reflection processing is given, which suffers again from excessive abbreviation. If anyone reading the section on migration for the first time actually gains any understanding of how migration by any technique is accomplished, I should be greatly surprised. An introduction to tomography and VSPs, given in Chapter 5, is welcome in an introductory book of this nature. The chapter on seismic refraction covers a wide range of aspects, including the tau-p transform, but even this potentially powerful approach to inverting the data is only described as a method for filtering noise that may equally well be accomplished in the f-k domain. Important concepts such as that of delay times are not included, yet elevation corrections for refraction are included whereas they were barely mentioned in the context of seismic reflection. It would not be possible for someone reading this chapter alone to make a sensible interpretation of seismic refraction data. This book could serve as a rapid introduction to seismic exploration. It starts with a sound explanation of the theory of seismic waves and it provides a good overview of the methods for acquiring seismic data. On other aspects it is very uneven. This must derive, in part at least, from the constraint of the short length of the book, but the problems of an overbrief treatment of many topics could have been ameliorated if much fuller reference had been made to other texts where these topics are treated at greater length and in more detail.
G. Westbrook School of Earth Science, University of Birmingham, UK
Induction Logging A. A. Kaufman and G. V. Keller Methods in Geochemistry and Geophysics, 27; Elsevier; 1989; ISBN 0 444 42949 2; Price US$205.25, Df1390.00; 600 pp Induction logging is one of the most important techniques used in the evaluation of hydrocarbon reservoirs. Induction sondes provide spatially continuous estimates of the electrical conductivity of formations penetrated by a well that has been drilled with freshwater or oil-based muds. The conductivity
118
data are interpreted in terms of the water content, and by difference of the hydrocarbon content, of the porous system. Because of this fundamental role, induction logging has been the subject of extensive research and development over the past 40 years. Much of this research has been directed at an
Marine and Petroleum Geology, 1991, Vol 8, February
Book reviews improved understanding of what induction tools actually measure, as a basis for subsequent improvements in measurement technology. Although this research has been strongly driven by the commercial demands of the oil industry in the western world, a substantial amount has been undertaken in the eastern hemisphere, most notably in the Soviet Union. Comparatively little of this work has been integrated with the efforts in the west. For some time, therefore, there has been a need to make available to western scientists and technologists, in a compiled and digestible form, the theory and practice of induction logging as developed in the Soviet Union. Kaufman and Keller have set out to satisfy that need from the particular standpoint of the theory of the induction method. The authors are eminently qualified to take on this role. Kaufman has been extensively involved in advancing the science of induction logging in the Soviet Union. Keller, from his base at the Colorado School of Mines, has long taken an interest in geophysical developments in the eastern hemisphere. In view of the stated aim of the book, i.e. 'to bring to the attention of western geophysicists the theory of the (induction) method as developed in the Soviet Union', and the authors' backgrounds, the reader would expect to see the text founded on a comprehensive and wide-ranging bibliography. Of the 53 cited references, 46 relate to material published in eastern Europe and, of these, 31 are ascribed to the senior author. Thus, the text lists no more than 15 references from the Soviet literature which have not been written by the senior author. The historical introduction contains a number of further citations which have not been transposed into the bibliography. Approximately one-sixth of the book is devoted to a foundation chapter on the basic laws of electromagnetism. This is followed by the development of a theory of induction logging for a two-coil induction sonde in a uniform conducting medium: skin effect is treated prominently. In Chapter 3 the relationship is examined between the electromagnetic field, as measured by the receiving coil, and the resistivity of the medium in which the sonde is located. Chapter 4 provides a substantial treatment of the vertical component of the (secondary) magnetic field on the axis of a borehole when the primary field is induced by a vertical magnetic dipole in an infinitely thick medium. The frequency responses of the quadrature and in-phase components of the
field receive special attention, as do environmental considerations. In Chapters 5 and 6 these ideas are extended to include the vertical responses of two-coil induction probes located on the borehole axis and surrounded by a bed of finite thickness. Key issues are the frequency responses, resistivity contrast, sonde dimensions, bed thickness, borehole characteristics, and the effect of fluid invasion. This investigation forms a basis for the theory of multi-coil induction sondes. Chapter 7 deals with multi-coil differential induction sondes which can be viewed as comprising several two-coil probes. These can be designed to enhance the vertical and radial responses of an induction log. Multi-coil differential induction sondes are commercial standards. In Chapter 8 the authors consider the relative merits of induction logging using measurements of in-phase or quadrature components of the prevailing magnetic fields. Chapter 9 deals with the alternative approach of induction logging in the time domain, for infinite uniform media and for media with cylindrical and horizontal interfaces. Chapter 10 moves away from vertical magnetic dipoles as field sources and considers horizontally oriented coils. The aim is to increase the sensitivity of induction logging by enhancing the vertical resolution of the probe. Finally, Chapter 11 examines the field due to a magnetic dipole in anisotropic media, the latter being classified as comprising layered (isotropic) beds, as being uniformly anisotropic, or as a combination of the two in the form of an interval of finite thickness. More generally, the text concentrates on horizontal layers, presumably because the development of a theory for dipping beds is extremely complex. In other respects, the work looks beyond the confines of induction logging as practised commercially, taking a refreshing, classical geophysical approach to induction measurements downhole. This comprehensive work combines a sound theoretical foundation of induction logging with the benefits of a substantial input from the Soviet literature, which can be difficult to access. The book will be of value to specialists in logging technology as well as to those who have a more general interest in electromagnetic applications.
Paul F. Worthington BP Research, Sunbury, UK
Trace Fossils: Biology and Taphonomy R. G. Bromley Unwin-Hyman Ltd; 1989; ISBN 0 044455 03 5 (hard cover), 0 044456 86 7 (soft cover). Price: £40.00 (hard cover), £17.95 (soft cover) This book is about how and why organisms leave traces in sediments, the inclusion of these traces into the fossil record and methods that can be applied in their interpretation. The book is divided into two parts, the first deals with neoichnology, the study of recent traces and the organisms that produce them. Initial chapters cover terminology, the reasons for the formation of traces, the different categories of trace and the importance of the influence of the substrate on traces. The three following chapters examine the lifestyles and formation of traces of a wide variety of organisms, using case examples which illustrate the different groups of trace fossil formed. A final chapter in this section deals with the interrelationship of different organisms with one another and the substrate. The second part of the book is concerned with palaeoichnology. Different chapters deal with preservation, guiding principles in interpretation, taxonomy and classification, trace fossil assemblages, diversity and facies and trace fossil assemblage recognition in cores. The book also includes a glossary of trace fossil terms and is profusely illustrated with drawings and photographs.
Trace fossils is aimed at advanced students and not as a general introduction to ichnology. It is, however, a very readable book for the non-specialist geologist. The glossary of terms helps the reader through many of the chapters, but the early chapters concerning case studies of trace formation are a little hard going for those who don't work with the morphology and classification of worms, cnidarians, molluscs, etc. on a daily basis. The book's approach to trace fossil formation, then the fossilisation process and finally trace fossil interpretation is a very logical and more scientific approach, than the reverse order adopted by many previous texts. The inclusion of a chapter dealing with trace fossils in core is very useful as many of the encounters of industrial geologists with trace fossils will be in this form. The paperback version of this book is very reasonably priced and well worth buying for those wishing to update their knowledge of trace fossils or for the more specialized reader.
Jason Crux BP Exploration Houston, TX, USA
Marine and Petroleum Geology, 1991, Vol 8, February
119
papers on the determination of in situ stresses in sediments and basalts, one paper that deals with the electrical properties of basalts and the implications for pore geometry, and a fourth that evaluates Christensen's equation for the prediction of shear-wave velocity and engineering parameters. Overall, the collected papers constitute an interesting and varied representation of topical geological issues and how these are being addressed through down-hole measurements. The technical quality seems remarkably consistent for a multi-authored work. In view of its uniqueness, the book will attract a good deal of interest among those involved in the quantitative geological description of both sedimentary and basement rocks.
Paul Worthington BP Research, Sunbury, UK
Seismic Methods Michel Lavergne Editions Technip; 1989; Price: FF340; 192 pp Seismic Methods is a short book (173 pages, including the index and references) that covers all aspects of both seismic reflection and seismic refraction exploration techniques from the theory of propagation of seismic waves, through signal theory and data acquisition, to data processing. Perhaps inevitably, some aspects receive a more detailed treatment than others. The chapter on the propagation of seismic waves lays a solid detailed foundation for what follows. It gives a more detailed treatment than several much larger books on the seismic method and is clearly and concisely laid out. It starts from the stress and strain tensors and gives a short but thorough treatment of the main aspects of seismic wave propagation including the different forms of seismic wave, acoustic impedance, reflection and transmission at interfaces, propagation in homogenous and inhomogenous media and anelastic effects. In the chapter on seismic signals, difficulties arise because of the breadth of the subject that is covered in 23 pages, i.e. definition of signal and noise, seismic pulse, Fourier transform, convolution, cross and auto correlation, analytical signal and trace attributes, wave-number filters, synthetic seismograms, multiples, Vibroseis, vertical and horizontal resolution. The reader who already knows the subject in some depth will be able to use this chapter as a quick aide memoir on some points (the section on synthetic seismograms is probably the best part), but I wonder how easily someone studying the subject for the first time will manage the highly abbreviated presentation. The concept and use of the Fourier transform is very sparsely stated and no reference is given in the text to where a fuller and more explanatory treatment may be found, This is not helped by some errors, possibly of translation. For example, it is stated that Figure 3.3 shows examples of signals and their Fourier transforms, whereas what is actually shown are examples of signals and their amplitude and phase spectra. The book is more successful in giving an account of
the acquisition of seismic reflection data in Chapter 4, which reviews all the modern techniques including shear-wave surveys, although I do not understand why a section on the geometry of reflected rays and the definition of RMS velocity occurs in the middle of the chapter. A t the end of the chapter a somewhat uneven treatment of seismic reflection processing is given, which suffers again from excessive abbreviation. If anyone reading the section on migration for the first time actually gains any understanding of how migration by any technique is accomplished, I should be greatly surprised. An introduction to tomography and VSPs, given in Chapter 5, is welcome in an introductory book of this nature. The chapter on seismic refraction covers a wide range of aspects, including the tau-p transform, but even this potentially powerful approach to inverting the data is only described as a method for filtering noise that may equally well be accomplished in the f-k domain. Important concepts such as that of delay times are not included, yet elevation corrections for refraction are included whereas they were barely mentioned in the context of seismic reflection. It would not be possible for someone reading this chapter alone to make a sensible interpretation of seismic refraction data. This book could serve as a rapid introduction to seismic exploration. It starts with a sound explanation of the theory of seismic waves and it provides a good overview of the methods for acquiring seismic data. On other aspects it is very uneven. This must derive, in part at least, from the constraint of the short length of the book, but the problems of an overbrief treatment of many topics could have been ameliorated if much fuller reference had been made to other texts where these topics are treated at greater length and in more detail.
G. Westbrook School of Earth Science, University of Birmingham, UK
Induction Logging A. A. Kaufman and G. V. Keller Methods in Geochemistry and Geophysics, 27; Elsevier; 1989; ISBN 0 444 42949 2; Price US$205.25, Df1390.00; 600 pp Induction logging is one of the most important techniques used in the evaluation of hydrocarbon reservoirs. Induction sondes provide spatially continuous estimates of the electrical conductivity of formations penetrated by a well that has been drilled with freshwater or oil-based muds. The conductivity
118
data are interpreted in terms of the water content, and by difference of the hydrocarbon content, of the porous system. Because of this fundamental role, induction logging has been the subject of extensive research and development over the past 40 years. Much of this research has been directed at an
Marine and Petroleum Geology, 1991, Vol 8, February
Book reviews improved understanding of what induction tools actually measure, as a basis for subsequent improvements in measurement technology. Although this research has been strongly driven by the commercial demands of the oil industry in the western world, a substantial amount has been undertaken in the eastern hemisphere, most notably in the Soviet Union. Comparatively little of this work has been integrated with the efforts in the west. For some time, therefore, there has been a need to make available to western scientists and technologists, in a compiled and digestible form, the theory and practice of induction logging as developed in the Soviet Union. Kaufman and Keller have set out to satisfy that need from the particular standpoint of the theory of the induction method. The authors are eminently qualified to take on this role. Kaufman has been extensively involved in advancing the science of induction logging in the Soviet Union. Keller, from his base at the Colorado School of Mines, has long taken an interest in geophysical developments in the eastern hemisphere. In view of the stated aim of the book, i.e. 'to bring to the attention of western geophysicists the theory of the (induction) method as developed in the Soviet Union', and the authors' backgrounds, the reader would expect to see the text founded on a comprehensive and wide-ranging bibliography. Of the 53 cited references, 46 relate to material published in eastern Europe and, of these, 31 are ascribed to the senior author. Thus, the text lists no more than 15 references from the Soviet literature which have not been written by the senior author. The historical introduction contains a number of further citations which have not been transposed into the bibliography. Approximately one-sixth of the book is devoted to a foundation chapter on the basic laws of electromagnetism. This is followed by the development of a theory of induction logging for a two-coil induction sonde in a uniform conducting medium: skin effect is treated prominently. In Chapter 3 the relationship is examined between the electromagnetic field, as measured by the receiving coil, and the resistivity of the medium in which the sonde is located. Chapter 4 provides a substantial treatment of the vertical component of the (secondary) magnetic field on the axis of a borehole when the primary field is induced by a vertical magnetic dipole in an infinitely thick medium. The frequency responses of the quadrature and in-phase components of the
field receive special attention, as do environmental considerations. In Chapters 5 and 6 these ideas are extended to include the vertical responses of two-coil induction probes located on the borehole axis and surrounded by a bed of finite thickness. Key issues are the frequency responses, resistivity contrast, sonde dimensions, bed thickness, borehole characteristics, and the effect of fluid invasion. This investigation forms a basis for the theory of multi-coil induction sondes. Chapter 7 deals with multi-coil differential induction sondes which can be viewed as comprising several two-coil probes. These can be designed to enhance the vertical and radial responses of an induction log. Multi-coil differential induction sondes are commercial standards. In Chapter 8 the authors consider the relative merits of induction logging using measurements of in-phase or quadrature components of the prevailing magnetic fields. Chapter 9 deals with the alternative approach of induction logging in the time domain, for infinite uniform media and for media with cylindrical and horizontal interfaces. Chapter 10 moves away from vertical magnetic dipoles as field sources and considers horizontally oriented coils. The aim is to increase the sensitivity of induction logging by enhancing the vertical resolution of the probe. Finally, Chapter 11 examines the field due to a magnetic dipole in anisotropic media, the latter being classified as comprising layered (isotropic) beds, as being uniformly anisotropic, or as a combination of the two in the form of an interval of finite thickness. More generally, the text concentrates on horizontal layers, presumably because the development of a theory for dipping beds is extremely complex. In other respects, the work looks beyond the confines of induction logging as practised commercially, taking a refreshing, classical geophysical approach to induction measurements downhole. This comprehensive work combines a sound theoretical foundation of induction logging with the benefits of a substantial input from the Soviet literature, which can be difficult to access. The book will be of value to specialists in logging technology as well as to those who have a more general interest in electromagnetic applications.
Paul F. Worthington BP Research, Sunbury, UK
Trace Fossils: Biology and Taphonomy R. G. Bromley Unwin-Hyman Ltd; 1989; ISBN 0 044455 03 5 (hard cover), 0 044456 86 7 (soft cover). Price: £40.00 (hard cover), £17.95 (soft cover) This book is about how and why organisms leave traces in sediments, the inclusion of these traces into the fossil record and methods that can be applied in their interpretation. The book is divided into two parts, the first deals with neoichnology, the study of recent traces and the organisms that produce them. Initial chapters cover terminology, the reasons for the formation of traces, the different categories of trace and the importance of the influence of the substrate on traces. The three following chapters examine the lifestyles and formation of traces of a wide variety of organisms, using case examples which illustrate the different groups of trace fossil formed. A final chapter in this section deals with the interrelationship of different organisms with one another and the substrate. The second part of the book is concerned with palaeoichnology. Different chapters deal with preservation, guiding principles in interpretation, taxonomy and classification, trace fossil assemblages, diversity and facies and trace fossil assemblage recognition in cores. The book also includes a glossary of trace fossil terms and is profusely illustrated with drawings and photographs.
Trace fossils is aimed at advanced students and not as a general introduction to ichnology. It is, however, a very readable book for the non-specialist geologist. The glossary of terms helps the reader through many of the chapters, but the early chapters concerning case studies of trace formation are a little hard going for those who don't work with the morphology and classification of worms, cnidarians, molluscs, etc. on a daily basis. The book's approach to trace fossil formation, then the fossilisation process and finally trace fossil interpretation is a very logical and more scientific approach, than the reverse order adopted by many previous texts. The inclusion of a chapter dealing with trace fossils in core is very useful as many of the encounters of industrial geologists with trace fossils will be in this form. The paperback version of this book is very reasonably priced and well worth buying for those wishing to update their knowledge of trace fossils or for the more specialized reader.
Jason Crux BP Exploration Houston, TX, USA
Marine and Petroleum Geology, 1991, Vol 8, February
119