Abstract This is the second book in what will not be an endless series of collections of Interpreter Sam stories from TLE. The first book in the series, published in 2009 as The Misadventures of Interpreter Sam, includes the Interpreter Sam columns from February 2003 through October 2008, and this volume seamlessly follows up with the February 2009 column and continues through columns published in 2016. By the words “carries on” in the title of this book, I intend to convey Sam’s sense of dogged persistence in pursuing his career and telling his stories; at the same time, I recognize that the same words might call to mind images of ceaseless complaining and ranting. Ultimately, readers will decide which of these more accurately describes Sam.

Abstract This book questions a basic assumption of the scientific method – that new theories or experimental results are communicated effectively by traditional methods (e.g., presentations at professional meetings or publication in a peer-reviewed journal) – and suggests that the scientific method needs to be applied to the scientific method itself to find out if other styles of communication might work better. In a highly entertaining format, the book uses the enormously popular fictional characters created by Sir Arthur Conan Doyle to unravel and explain the historical underpinnings of remote sensing. The extended appendices guarantee that all of the science of remote sensing is included in this book of “scientific fiction.” The story covers more than 2000 years, beginning with Pythagoras in ancient Greece and ending with Einstein’s first article on relativity in 1905. Light-years beyond a traditional science textbook, this detective story set in 1905 will teach students of all ages about the exciting journey of scientific discovery.

Abstract This book aims to help you to extract maximum value from aeromagnetic survey data. It shows how to integrate these data with geological data to build an interpretation that matches the objectives of your project. We emphasise that the main ingredients in a high-quality interpretation are astute use of the geoscientist’s brain and adequate time, not only to digest diverse clusters of data, but to integrate these into a working map that drives our project forward. The rewards for this (usually modest) effort and time can be substantial – a resource discovery, a quantum leap in understanding of local geological evolution or a new direction and momentum in exploration, to name a few.

Abstract The goal of this book is to provide information about the principles, understanding, and applicability of the gravity exploration method. This book is intended to be suitable for classroom instruction and as a reference for anyone engaged in geophysical exploration, including those whose specialties might be in another discipline but who would benefit from an understanding of how gravity exploration can help them solve exploration problems. For many decades, the 1971 SEG book by L. L. Nettleton (Geophysical Monograph Series No. 1, Elementary Gravity and Magnetics for Geologists and Seismologists ) has helped to fill this need, but it is limited in scope (as its title implies) and is, of course, out of date, especially with respect to modern exploration technology. This little book has been a best seller, however, and it resides in the libraries of thousands of geologists and geophysicists. It contains several classical and practical examples of how the gravity method can be applied, and we have borrowed liberally from these where they retain their long-held value. In 1995, Richard J. Blakely published Potential Theory in Gravity and Magnetic Applications . This book covers in depth much of which the Nettleton monograph lacks: the principles of potential theory and the mathematical basis for the forward and inverse techniques of interpretation. Our book is intended to fill a need that is oriented more toward exploration than the Nettleton monograph or the Blakely book, with more information about the underlying principles and technology than the former and clearer orientation toward the explorationist's geologic goals than the latter.

Abstract Accurate interpretation of geophysical data — in particular, reflection seismic data — is one of the most important elements of a successful oil and gas exploration program. Despite technological advances in data acquisition and processing and the regular use of powerful computers and sophisticated software applications, you still face a tremendous challenge each time you begin to reconstruct the geologic story contained in a grid or volume of seismic data — that is, to interpret the data. On occasion, this interpretive tale can be clearly told; but most of the time, each page of each chapter is slowly turned, and rarely is the full meaning of the story completely understood. Where the correlation of one reflection record with another is very easy, little needs to be said. Almost anyone can understand such a correlation. On the other hand, this is a rare occurrence. The usual thing is for the correlation to be so difficult as to be impossible. It is for this reason that correlation procedure can hardly be described in words (Dix, 1952). Although Dix is speaking about the correlation of individual reflection records, which were used routinely before the advent of continuous common-depth-point (CDP) profiling, he clearly recognized the essence of interpretation as the considered extraction of geologic information from indirect geophysical measurements. His words are no less relevant and applicable now than they were 60 years ago, even in view of the high standards of data quality made possible by advances in seismic acquisition and processing, to say nothing of accompanying developments in interpretation technology. In the modern interpretation environment, you still face correlations that are “so difficult as to be impossible“ because these correlations define the frontiers of opportunity, the ones posing the sternest challenges and ultimately leading to the greatest rewards. The primary aim of this book is to describe Dix's correlation procedure in terms of the science, data, tools, and techniques now used in seismic interpretation in the oil and gas industry. As an individual geoscientist, you develop and apply your own approach and style when interpreting seismic data. You continually revise and refine correlation procedures during the course of your career and expand them as you complete different interpretation projects. With experience, you learn to check and recheck the validity of your procedures to fully understand the rules of evidence that govern their use: You must have a good understanding of seismic acquisition and processing principles as well as fundamentals of geology before beginning to collect interpretive evidence and solve interpretation problems correctly.

Abstract In Edge and Tip Diffractions: Theory and Applications in Seismic Prospecting (SEG Geophysical Monograph Series No. 14), the theoretical framework of the edge and tip wave theory of diffractions has been elaborated from fundamental wave mechanics. Seismic diffractions are inevitable parts of the recorded wavefield scattered from complex structural settings and thus carry back to the surface information that can be exploited to enhance the resolution of details in the underground. The edge and tip wave theory of diffractions provides a physically sound and mathematically consistent method of computing diffraction phenomena in realistic geologic models. In this book, theoretical derivations are followed by their numerical implementation and application to real exploration problems. The book was written initially as lecture notes for an internal course in diffraction modeling at Norsk Hydro Research Center, Bergen, Norway, and later was used for a graduate course at Novosibirsk State University in Russia. The material is drawn from several previous publications and from unpublished technical reports. Edge and Tip Diffractions will be of interest to geoscientists, engineers, and students at graduate and Ph.D. levels.

Abstract Among geophysical methods, there are many techniques which use the “natural field,” “natural signal,” or “natural phenomena.” For example, they include the gravity survey method, the magnetic survey method, the spontaneous potential (SP) measurement in electrical methods, the magnetotelluric method in the electromagnetic methods, and radiometric measurements (Dobrin and Savit, 1988; SEGJ, 1989). These are known as “natural field methods.” These survey methods have been initiated, researched, and developed as means of understanding geological structure by measurement of the respective physical property. They are presently used in their own right or to augment other survey methods, but typically they are utilized as a reconnaissance method prior to committing to a detailed survey such as reflection or refraction seismic surveys. The ubiquitous, weak, low amplitude vibrations which may be recorded on the surface of the Earth are commonly called microtremors. These form one category of the “natural signals” or “natural phenomena.” Until recently, there has not been an established method to positively harness this natural phenomenon for estimation of subsurface structure. Several research projects during the mid-twentieth century documented the kinds of waves that constitute microtremors and the relationship between microtremors and subsurface structure. Among them Aki 1957) and Toksoz 1964 suggested a potential application of microtremors to the estimation of subsurface structure. Research progressed through the 1970s concentrating on the detection of earthquake waves in records contaminated by noise, such as microtremors and pulsation (e.g., Capon, 1969). The success of research was facilitated by the concurrent development of digital recording systems that enabled the recording of earthquake data by multiple array observation networks and the processing and analysing of such data. The results of this researchwere applied to the detection of traveling waves among other kinds of vibration. In fact, such techniques were used to estimate subsurface structure (e.g., Lacoss et al., 1969; Liaw and McEvilly, 1979; Asten and Henstridge, 1984; Horike, 1985; and Matsushima and Okada, 1990a). The development of a new exploration method, designated the microtremor survey method (MSM) by Okada et al. (1990), for imaging subsurface structure, using natural microtremors has advanced over the last ten years. This survey method, if used effectively, can furnish a preliminary appraisal before a detailed survey for geological structure. Alternatively, this can be a means of extending scarce detailed data from point data to profile data, or profile data to plane data." As the MSM utilizes the signal found in abundance anywhere on the surface of the Earth, the survey is simple and the operation does not require intensive environmental and safety precautions.

Abstract Reflection and transmission of plane waves at a plane boundary between two isotropic media are two of the most fundamental subjects in wave propagation. Zoeppritz (1919) w as among the first to investigate and publish their analytic solutions. Given the medium properties on both sides of a reflector and invoking continuity of stress and displacement across the interface, he came up with a set of equations to describe the amplitudes of the scattered (i.e., reflected and transmitted) waves. Chapter 2 provides an overview of the reflection and transmission problem in isotropic media. It also introduces the notation that is used throughout the text and contains a review of the basic physical principles that lead to the boundary conditions for media in welded contact. Because of the algebraic complexity of the Zoeppritz equations, the inverse problem of esti-mating medium properties from the reflection signature is based mostly on approximate analytic expressions for reflection coefficients. Several approximations for isotropic models have been described in the literature (Richards and Frasier, 1976; Aki and Richards, 1980; Shuey, 1985; Thomsen, 1990). As described in Chapter 2 , they differ in their assumptions, as well as in the choice of medium parameters.

Abstract The boundary element method (BEM) divides only the boundaries of the region under investigation into elements, so it diminishes the dimensionality of the problem, e.g., the 3D problem becomes a 2D problem, and the 2D problem becomes a 1D problem. This simplifies inputting the model into a computer and greatly reduces the number of algebraic equations. The advantage of this is even more evident for some 3D and infinite regional problems that often are encountered in geophysics. Originally published in China, this well-organized book is likely the most comprehensive work on the subject of solving applied geophysical problems. Basic mathematical principles are introduced in Chapter 1, followed by a general yet thorough discussion of the BEM in Chapter 2. Chapters 3 through 7 introduce the applications of BEM to solve problems of potential-field continuation and transformation, gravity and magnetic anomalies modeling, electric resistivity and induced polarization field modeling, magnetotelluric modeling, and various seismic modeling problems. Finally, in Chapter 8, a brief discussion is provided on how to incorporate the BEM and the finite-element method (FEM) together. In each chapter, detailed practical examples are given, and comparisons to both analytic and other numerical solutions are presented. This is an excellent book for numerically oriented geophysicists and for use as a textbook in numerical-analysis classes.

Abstract The science of seismology began with the study of naturally occurring earthquakes. Seismologists at first were motivated by the desire to undetand the destructive nature of large earthquakes. They soon learned, however, that the seismic waves produced by an earthquake contained valuable information about the large-scale structure of the Earth’s interior. Today, much of our understanding of the Eart’s mantle, crust, and core is based on the analysis of the seismic waves produced by earthquakes. Thus, seismology became an important branch of geophysics, the physics of the Earth. Seismologists and geologists also discovered that similar, but much weaker, man-made seismic waves had a more practical use: They could probe the very shallow structure of the Earth to help locate its mineral, water, and hydrocarbon resources. Thus, the seismic exploration industry was born, and the seismologists working in that industry came to be called exploration geo-physicists. Today seismic exploration encompasses more than just the search for resources. Seismic technology is used in the search for waste-disposal sites, in determining the stability of the ground under proposed industrial facilities, and even in archaeological investigations. Nevertheless, since hydrocarbon exploration is still the reason for the existence of the seismic exploration industry, the methods and terminology explained in this book are those commonly used in the oil and natural gas exploration industry. The underlying concept of seismic exploration is simple. Man-made seismic waves are just sound waves (also called acoustic waves) with frequencies typically ranging from about 5 Hz to just over 100 Hz. (The lowest sound frequency audible to the human ear is about 30 Hz.) As these sound waves leave the seismic source and travel downward into the Earth, they encounter changes in the Earth’s geological layering, which cause echoes (or reflections) to travel upward to the surface. Electromechanical transducers (geophones or hydrophones) detect the echoes arriving at the surface and convert them into electrical signals, which are then amplified, filtered, digitized, and recorded. The recorded seismic data usually undergo elaborate processing by digital computers to produce images of the earth’s shallow structure. An experienced geologist or geophysicist can interpret those images to determine what type of rocks they represent and whether those rocks might contain valuable resources.

Abstract We define tomography as an imaging technique which generates a cross-sectional picture (a tomogram) of an object by utilizing the object's response to the nondestructive, probing energy of an external source. Seismic tomography makes use of sources that generate seismic waves which probe a geological target of interest. Figure 1(a) is an example configuration for crosswell seismic tomography. A seismic source is placed in one well and a seismic receiver system in a nearby well. Seismic waves generated at a source position (solid dot) probe a target containing a heavy oil reservoir situated between the two wells. The reservoir's response to the seismic energy is recorded by detectors (open circles) deployed at different depths in the receiver well. The reservoir is probed in many directions by recording seismic energy with the same receiver configuration for different source locations. Thus, we obtain a network of seismic raypaths which travel through the reservoir. The measured response of the reservoir to the seismic wave is called the projection data. Tomography image reconstruction methods operate on the projection data to create a tomogram such as the one in Figure 1(b). In this case we used projection data consisting of direct-arrival traveltimes and seismic ray tomography to obtain a P-wave velocity tomogram. Generally, different colors or shades of gray in a tomogram represent lithology with different properties. The high P-wave velocities (dark gray/black) in the tomogram in Figure 1(b) are associated with reservoir rock of high oil saturation. Seismic tomography has a solid theoretical foundation. Many seismic tomography techniques have close ties to more familiar seismic imaging methods such as traveltime inversion, Kirchhoff migration, and Born inversion. For example, seismic ray tomography used to determine lithologic velocity is essentially a form of traveltime inversion and seismic diffraction tomography is closely related to Born inversion and seismic migration. Thus, seismic tomography may actually be more familiar to you at this point than you might think since it is just another aspect of the subsurface imaging techniquesg eophysicistsh ave been using for years.

Abstract In this short monograph, 1D inversion methods are examined collectively using a uniform notation. One-dimensional inversion methods are still important because there are geologic regions where lateral variation is small and 1D interpretation is directly applicable; 1D inverse solutions provide good starting models for 2D inversion; and understanding the 1D inverse problem provides a foundation for solving inverse problems in higher dimensions. The 10 chapters are “Introduction”, “Existence”, “Uniqueness,” “Asymptotic Methods,” “Linearized/Iterated Methods,” “Global Penalty Functional Methods,” “Monte Carlo Methods,” “Exact Methods,” “Appraisal Methods,” and “Conclusion.”

Abstract “This book grew out of an attempt to understand the mechanisms through which band-limited reflection seismograms determine velocity distributions in elastic models of the earth's crust. The authors were especially interested in the feasibility of recovering very slowly varying (out-of-passband) velocity components from band-limited (highfrequency) reflection data. That interest was spurred by reports of successful inversions for layered media.”

Abstract “This booklet expands on the interpretation traps listed in SEG's popular monograph Pitfalls in Seismic Interpretation. Nontechnical and mental pitfalls are outlined in the sections on velocity, geometry, recording and processing, and stratigraphic traps.”

Abstract “The authors' wisdom regarding pitfalls in interpretation is born of experience, not all of which was pleasant. Their work will be appreciated by all explorationists who have found that the earth's crust and its seismic events are not well ordered. This monograph's unique style makes delightful reading.”

The purpose of this work is a general review of the gravity and magnetic nlethodsods of geophysicael xplorationa s applied in the search for petroleum. This material is not designed for the gravity and magnetic specialistb ut rather lo)r the geologistsa nd seismologistwsh o may not have a thorough appreciation of the applications of these metht)ds in the overall expl()ration picture. A subtitlc for this monograph might well be "-l'hc Other Five Percerot." This is because the seismic method and its associated data processing account for sornc 95 percent of the total expenditures Ik)r petroleum exploration geophysicss o that whatever application is made of the gravity and magnetic noethods comes out of the other 5 percent. This does not mean that these methods make a proportionately small contribution to the overall exploration effort. Because of the relatively rapid rate of progress in the field, particularly by airborne magnetics. the total area covered by gravity and magnetic surveys may bc greater than that covered by the much greater seismic expendituresA. s a very rough rule-ofthumb, the relative cost per unit area of magneticg, ravity and seismicf ield work with data processings tand in the ratio of I to 10 to 100. It is the hope and purposeo f this monographth at a better appreciatioonf the valueo f the potential methods and understanding of their applicationsm ay be broughta bouts t) that they can be applied with proper perspective in the overall exploration picture. From the beginning of geophysical exploration in the petroleum industry in the 192()'s, three basic physical principles were used: i.e., the measurement of small variations in the magnetic field, the measurement of small variations in the gravitational field, and the propagation of elastic waves through the earth. These three and only these three physical principles are the basis for practically all of the geophysical work up to the present time. Many other methods have been conceived and tried in the field in a limited way, but none has persisted to the extent that field operations are carried out n a scale at all comparable with that of the three primary methods listed above. The seismic method, of course, usually is much more direct in its relation to the geologyt han the potentialm ethodsR. etlection zones or horizons frequently are directly correlative with geologic strata and give relativelya ccuratem easureosf their depth and form.