Twenty years ago, the objectives of the ?rst edition of this book were numerous and ambitious:todemystifytheprocessofwellloganalysis;toexaminethephysicalbasis of the multitude of geophysical measurements known collectively as well logging; to clearly lay out the assumptions and approximations routinely used to extract pet- physical information from these geophysical measurements; to expose the vast range of well logging instrumentation and techniques to the larger geophysical community. Finally,therewastheimportantgoalofprovidingatextbookforuniversityandgra- atestudents inGeophysics andPetroleum Engineering, wherenone suitablehad been available before. What’s different twenty years later? First of all, Well Logging for Earth Scientists is long out of print. The petroleum industry, the major consumer of the geophysical information known as well logging, has changed enormously: technical staffs have been slashed, and hydrocarbons have become increasingly harder to locate, quantify, and produce. In addition, new techniques of drilling high deviation or horizontal wells have engendered a whole new family of measurement devices incorporated into the drilling string that may be used routinely or in situations where access by traditional “wireline” instruments is dif?cult or impossible. Petroleum deposits are becoming scarce and demand is steadily increasing. Massive corporate restructuring and the “graying” of the workforce have caused the technical competence involved in the search and exploitation of petroleum to become scarce. Although we are only attempting to address this latter scarcity with our textbook, the objectives are still ambitious.
Well logging lies at the intersection of applied geophysics, petroleum and geotechnical engineering. It has its roots in the tentative electrical measurements in well bores which were made by the Schlumberger brothers some 80 years ago in the earliest days of systematic petroleum exploration. Today, a variety of specialized instruments is used to obtain measurements from the borehole during, as well as after, the drilling process. This readable and authoritative treatment of the physics of these measurements dispels the "black magic" of well log interpretation by relating them, including those obtained by the latest generation of tools, to rock physics. It offers a thorough exposé of the physical basis of borehole geophysical measurements, as well as an introduction to practical petrophysics -- extracting desired properties from well log measurements.
"Well Logging for Earth Scientists", 2 nd edition, is thoroughly revised and extended with three new chapters, manynew illustrations and expanded and updated references in each chapter.
Audience: This graduate level textbook with many exercises can also serve as a useful handbook for practicing earth scientists (geophysicists, geologists, or petroleum engineers).
