This book covers the principles, historical development, and applications of many acoustic logging methods, including acoustic logging-while-drilling and cased-hole logging methods. Benefiting from the rapid development of information technology, the subsurface energy resource industry is moving toward data integration to increase the efficiency of decision making through the use of advanced big data and artificial intelligence technologies, such as machine/deep learning. However, wellbore failure may happen if evaluations of risk and infrastructure are made using data mining methods without a complete understanding of the physics of borehole measurements. Processed results from borehole acoustic logging will constitute part of the input data used for data integration. Therefore, to successfully employ modern techniques for data assimilation and analysis, one must fully understand the complexity of wave mode propagation, how such propagation is influenced by the well, and the materials placed within the well (i.e., the cement, casing, and drill strings), and ultimately how waves penetrate into and are influenced by geological formations.
State-of-the-art simulation methods, such as the discrete wavenumber integration method (DWM) and the finite difference method (FDM), are introduced to tackle the numerical challenges associated with models containing large material contrasts, such as the contrasts between borehole fluids and steel casings. Waveforms and pressure snapshots are shown to help the reader understand the wavefields under various conditions. Advanced data processing methods, including velocity analyses within the time and frequency domains, are utilized to extract the velocities of different modes. Furthermore, the authors discuss how various formation parameters influence the waveforms recorded in the borehole and describe the principles of both existing and potential tool designs and data acquisition schemes.
This book greatly benefits from the research and knowledge generated over four decades at the Earth Resources Laboratory (ERL) of the Massachusetts Institute of Technology (MIT) under its acoustic logging program.
Given its scope, the book is of interest to geophysicists (including borehole geophysicists and seismologists), petrophysicists, and petroleum engineers who are interested in formation evaluation and cementation conditions. In addition, this book is of interest to researchers in the acoustic sciences and to 4th-year undergraduate and postgraduate students in the areas of geophysics and acoustical physics.
Prof. Hua Wang is currently a Full Professor at the University of Electronic Science and Technology of China and Team Leader of downhole information intelligent acquisition and processing. Before that he was Postdoctoral Researcher at Massachusetts Institute of Technology (from 2014 to 2018). He received his B.Sc. in Exploration Geophysics from China University of Petroleum, East China, in 2005. He received his Ph.D. in Exploration Geophysics from China University of Petroleum, Beijing, in 2012. The majority of his work has been dedicated to borehole geophysics, micro-seismicity induced by fluid injection in oil/gas exploration and geothermal exploitation, and exploration seismology. He has been working in the field of wave propagation in complex medium, especially in borehole, for over 15 years, with a number of grants in this area and a substantial number of research papers in reputation geophysics journal. He has several years of teaching experience in the field, and also worked asa Consultant Expert in a service company. He is now served as a co-Editor-in-Chief of Artificial Intelligence in Geosciences and an Associate Editor for the Journal of Petroleum Science and Engineering. He is also thePresident of the Southwest China Chapter of the Society of Petrophysicists and Well Log Analysts.
Prof. M. Nafi Toksöz is Robert R. Shrock Professor of Geophysics (Emeritus). He is the Founder of the Earth Resources Laboratory at Massachusetts Institute of Technology and was its Director from 1982 to 1998. He is also the Director of the George R. Wallace, Jr. Geophysical Observatory. He received his geophysical engineering degree at Colorado School of Mines and his M.S. and Ph.D. degrees in geophysics at the California Institute of Technology. He has been a faculty member in the Department of Earth, Atmospheric, and Planetary Sciences, M.I.T., since 1965. Prof. Toksöz has made major scientific contributions in many areas of geophysics, including seismic exploration, reservoir characterization, rock physics, plate tectonics, planetary interiors and earthquake seismology. He has received numerous scientific achievement awards including medals from NASA and Colorado School of Mines. In 1999, he was awarded with Honorary Membership by SEG. In 2006 he received the Harry Fielding Reid Medal of the Seismological Society of America. In 2010 he was presented with the Maurice Ewing Medal, the highest honor of SEG. He is a fellow of the American Geophysical Union, the Geological Society of America, Honorary member of the Society of Exploration Geophysicists, the Seismological Society of America and several other scientific societies. Prof. Toksöz is the author or co-author of more than 400 technical papers in geophysics, including many articles on geophysics and seismology. He has edited books and served on editorial boards of scientific journals. Prof. Toksöz has and continues to serve on scientific advisory and review committees for U.S. governmentagencies, universities, international organizations, and industry. His academic activities include teaching, leading several research projects, and advising a number of graduate students.
Dr. Michael Fehler received his Ph.D. in Geophysics from MIT in 1979. He then worked as an Assistant Professor at Oregon State University for five years before becoming a Staff Geoscientist at Los Alamos National Laboratory in 1984. At Los Alamos, he was the Leader of the Geophysics Group and later the Division Director of the Earth and Environmental Sciences Division. In 2008, he returned to MIT where he is a Senior Research Scientist and the Deputy Director of ERL. In addition to his work at MIT, Fehler is Technical Project Manager for Phase I of the SEG Advanced Modeling project (SEAM), an industry consortium for geophysical modeling. Fehler was Editor-in-Chief of the Bulletin of the Seismological Society of America for nine years beginning in 1995 and was President of the Seismological Society of America from 2005 to 2007. His current research interests include seismic imaging, reservoir characterization, seismic scattering, geothermal energy, and induced seismicity.
