Book Review

Well Seismic Surveying

by Jean-Luc Mari and Francoise Coppens,
ISBN 2-7108-0776-9, Institute Francais du Petrole Publications, 2003, 238 pp.
$90.00 USD.

This book represents 20 years of VSP progress and development at the Institute Francais du Petrole. This volume is an update of their 1991 book entitled Seismic Well Surveying. There is extensive mathematics showing many aspects of the VSP and crosswell technology. Patents are noted where appropriate.

The book is also extensive to the point that the reader must take their time to examine and conceptualize a lot of detailed concepts such as the review of wavefield separations and reflector dip analysis. Patented procedures are not thoroughly reviewed (SEISDIP, CLUB weight dropper, and SEISBIT); however, their results are shown.

The book is composed of five chapters along with a special chapter on using GPR for well imaging. Chapter 1 contains a quick glance of the geometries of the VSP surveying plus simple to advanced processing concepts (Up-going waves to VSP migration). The other discussions center around downhole sources (Reverse VSP), transmission and reflection tomography.

Chapter 2 heads straight into more detail on the type of recorded waves, a detailed look at the relationship between the Up-going, Down-going, and Multiple VSP events. A short review of cable and tube waves gets one primed for the extensive discussions and examples of using tube waves for petrophysical investigations within Chapter 5.The real datasets could be labelled more in order to familiarize the reader with VSP seismic events as they are seen on the various data panels used in VSP interpretation.

Chapter 3 is a testament to the innovativeness of the French Oil Industry. The sources and VSP sondes are reviewed along with field procedures. The use of VSPs in horizontal well environments illustrates the use of hodograms to allow the tri-axial wavefields to be partitioned and reveal more details along a non-vertical portion of the well.

The data processing used in vertical and deviated wellbores, walkover and walkaway VSPs in Chapter 4. The extensive list of wavefield separation methods include sum and difference, Median, Wiener, F-K (and Tau-P) filtering , SVD eigenvalue/ vector analysis, Spectral matrix, Polarization (axis scaling), Parametric, Dankbaar’s Method and the Pressure and Displacement method. The application of static corrections, NMO, corridor stacking and inversion is reviewed in the near-offset vertical well VSP processing. The non-zero offset processing reviews the hodogram, and VSPCDP/migration analysis. More detailed conceptual diagrams showing the migration process would be helpful to explain such a difficult subject. A seismic walkaway is fully explained and one realizes the value of the merged “seismic section” result. Finally, results for VSP migration in deviated well is shown.

The applications section is shown in Chapter 5. The use of VSP data to intimately tie well logs and surface seismic data is the first and most important concept to an explorationist. The use of high resolution seismic data when a seismic line is run near to the well brings out the link of a two well VSP profile to the sub-surface between the two wells. Shear and P waves are shown being able to provide a joint interpretation that can be used to see changes in Poisson’s ratio. A significant amount of the text shows the use of tube waves to look for changes in the petrophysical properties within the sub-surface. SIESDIP uses the source- receiver ellipsoid to predict the reflection points of waves traveling from a surface source to a downhole sonde. A case study shows that this enables the mapping of faults and structure around and beneath the well. Finally, the operational aspects and interpretation of Reverse VSP data, cross- borehole tomography and 4D VSPs are reviewed.

The final chapter reviews radar cross-borehole tomography and its use in Civil Engineering. ACD is enclosed that shows a quick review of the VSP method. This book is essential as a reference book and should be on the bookshelf of oil and gas explorationists. Many of the references listed within the text are missing from the back of the book; however, this is minor point when compared to the detailed explanation and reviews within the book.

Ronald Hinds
Talisman Energy, Calgary

SEDIMENTARY GEOLOGY – Sedimentary Basins, Depositional Environments, Petroleum Formation

by B. Biju-Duval,
ISBN 2-7108-0802-1 Institut Francais du Petrole Publications, Editions Technip, Paris, 2002, 642 pages, 1072 figures.
Translated from French to English by J. Edwin Swezey.
Cost: $146.00 USD.

The foreword of SEDIMENTARY GEOLOGY states that “this book is intended for engineering students in geology and geophysics, drillers, producers, and economists”(p.iv). Best of luck to them. Anyone attempting to read this textbook can expect to be inundated with obscure terminology and seriously challenged by awkward and sometimes downright incorrect translations. On the positive side, the text is abundantly illustrated (1072 figures) with a combination of diagrams, actual cross-sections, seismic lines, and photographs. Unfortunately, the accompanying figure captions do not explain the figures well enough to be understood by someone without an earth science background. A bibliography is compiled at the end of each chapter for easy reference and follow-up reading. These bibliographies are comprised mainly of text books dating from the 1970’s and 1980’s. Approximately half the references are written in French.

The book is organized into six chapters. Chapter One starts with a quick look at the “Basics of Dynamic Geology”. It condenses an amazing amount of diverse material into one chapter, including time scales, tools geologists use to describe the earth (maps, cross-sections), the internal structure of the earth (including the forces of magnetism, gravity, heat), plate tectonics, and oceanic currents. This chapter does flow logically, and the different facets of earth science are combined skillfully and imaginatively. It is refreshing to read “Geology concerns fluids every bit as much as it does solids (p.1)” however, a sentence in the following paragraph: “Then the movements of the water tables in the beds running along accidents, evidenced by water springs, for example, are important phenomena.” (also p.1) is confusing and frustrating. This chapter sets the tone for the entire book in many ways. It is a good, whirlwind review for someone with a foundation in geology, but too much too fast for ‘drillers, producers, and economists’. It is plagued with poor translations, and although there are many figures, they lose impact because the accompanying captions are frequently cursory.

“Continental and Oceanic Basins” are the topics for Chapter 2. This is one of the more interesting chapters in the text, taken from the point of view of the ‘receptacles’ or basins that sediments fill. This basin-scale perspective is missing from many textbooks. The more limited subject matter is a better fit for the chapter format, and Biju-Duval covers the basics well. He discusses classification, formation, and characteristics of different basin types, including everything from rifts to foreland fold belts. In addition, he illustrates the influence of subsidence and sedimentation rate. As in chapter 1, the figures are detailed and rich but poorly captioned so that they contribute little to the understanding of the text. (eg Fig.2.18, p.81).

Chapter 3, “Sedimentary Driving Forces and Mechanisms”, is the core of the book according to the Foreword. This immense chapter (193 pages) is certainly all encompassing. It attempts to cram in descriptions of a very wide range of sedimentary environments, sedimentary petrology, oceanography, and even some paleontology. The discussion of sedimentary environments in particular has some serious drawbacks. It is plagued by specialized and obscure jargon, such as “This formation of deposits over long distances is sometimes called fluvial spreading.” and “The weathered zone becomes a soft material or alterite, the upper part of which is the soil…” and “…or intermediate sandy fedj and special shapes found on quite another scale, such as the famous dreikanter and faceted pebbles.”(p.186, p.134, p.178 Biju- Duval’s emphasis). Some terms are completely mis-translated, as in the repeated use of carbonaceous for carbonate, as in “One particular and spectacular form of weathering in the carbonaceous medium is karstification…” (p.136). Although one does not expect a textbook to be completely current due to lags in publication and the scope of material covered, the inclusion of Walker’s 1978 turbidite model (p.310) is seriously out of date – especially considering the importance of deepwater depositional environments to international exploration. Attempted ties to the petroleum aspects of depositional environments are weak and even misleading as illustrated in this reference to fluvial environments (inclusive) as lacking fine sediments: ”The fluvial environment is thus an extremely favorable medium for constructing arenaceous reservoirs, with the added interest for the petroleum that they are coalescent and not sharply separated by the permeability barriers that fine sediments would set up.” This ‘core’ chapter does not supply a good backbone.

Chapter 4 addresses “Time Evolution: Sedimentary Sequences, Stratigraphy”. Topics covered include paleogeographic reconstructions, time scales, dating (relative, absolute, methods), and a discussion of gaps in the stratigraphic record. The concepts of facies – including seismic facies – and depositional sequences are introduced. The addition of paragraphs on seismic facies, and seismic facies analysis is welcome, but an emphasis on the differences in scale compared to geological examples should be included.

Chapter 5 looks at sediments after burial in “From Sediments to Sedimentary Basin Rocks and Mountain Chains”. Diagenesis (mechanical and chemical), an introduction to porosity and permeability, and some exposure to lab techniques are covered. In another bizarre translation mix-up, grading is used when sorting is the appropriate term. Figure 5.25 (p.453) illustrates “A. Good grading B. Poor grading C. Bad grading.” – not exactly common English geological usage. This figure caption goes on to state that “Porosity diminishes as the pore space is invaded by smaller particles” – where it is more correctly the permeability that is affected. From this detailed scale, the chapter broadens its perspective to look at the structural evolution of basins. Stress and strain ellipsoids, pore pressure, deformation types, and finally plate tectonics all have a place in this chapter.

Finally, Chapter 6 concludes with a good overview of “Petroleum Systems”. This chapter begins with definitions of types of petroleum compounds (but no explanation of the term ‘saturated’ in an organic chemistry context). The origin and generation of hydrocarbons is discussed, including the importance of euxinic environments. It is great to see sections on both biogenic gas and hydrates. Migration of hydrocarbons and their potential alteration and degradation is covered, then Biju-Duval moves on to reservoirs, traps and oil fields. A cursory discussion of architecture and heterogeneity includes irritating mis-uses and abuses of terms. Biju-Duval states that “the extent of lateral continuity is doubtless one of the simplest parameters to define…” (p.593) and “Under very favorable conditions, the total power (thickness) is considerable, as in certain cases of the Middle East .”(p.594, Biju-Duval’s emphasis). Most petroleum geologists would agree that lateral continuity is often difficult to define, and the use of the term ‘power’ in that context is very unorthodox.

In summary, this textbook reads like a compilation of other textbooks. It is well-organized, and covers an enormous range of subjects. Many illustrations include actual geologic cross-sections, seismic lines and photographs from all over the world. Unfortunately, lists of terms are poor substitutions for clear, concise explanations. Diagrams borrowed from advanced textbooks do not aid introductory readers. Out-of-date references are not fair to current audiences. Poor translations are frustrating and misleading. The relevance of many subjects of the book to finding and producing petroleum are poorly articulated. This textbook needs serious technical editing in its English format. The reader would be well advised to find other introductory texts on sedimentary geology.

Lisa Griffith
GEDCO, Calgary