Understanding Seismic Anisotropy In Exploration And Exploitation

Understanding Seismic Anisotropy in Exploration and Exploitation

All rock masses are seismically anisotropic, but we generally ignore this in our seismic acquisition, processing, and interpretation. The anisotropy nonetheless does affect our data, in ways that limit the effectiveness with which we can use it, as long as we ignore it. This book, produced for use with the fifth SEG/EAGE Distinguished Instructor Short Course, helps us understand why this inconsistency between reality and practice has been so successful in the past and why it will be less successful in the future as we acquire better seismic data (especially including vector seismic data) and correspondingly higher expectations of it. This book helps us understand how we can modify our practice to more fully realize the potential inherent in our data through algorithms which recognize the fact of seismic anisotropy.

Understanding Seismic Anisotropy in Exploration and Exploitation, Second Edition

Understanding Seismic Anisotropy in Exploration and Exploitation (second edition) by Leon Thomsen is designed to show you how to recognize the effects of anisotropy in your data and to provide you with the intuitive concepts that you will need to analyze it. Since its original publication in 2002, seismic anisotropy has become a mainstream topic in exploration geophysics. With the emergence of the shale resource play, the issues of seismic anisotropy have become central, because all shales are seismically anisotropic, whether fractured or not. With the advent of wide-azimuth surveying, it has become apparent that most rocks are azimuthally anisotropic, with P-wave velocities and P-AVO gradients varying with source-receiver azimuth. What this means is that analysis of such data with narrow-azimuth algorithms and concepts will necessarily fail to get the most out of this expensively acquired data. The issues include not only seismic wave propagation, but also seismic rock physics. Isotropic concepts including velocity, Young’s modulus, and Poisson’s ratio have no place in the discussion of anisotropic rocks, unless qualified in some directional way (e.g., vertical Young’s modulus). Likewise, fluid substitution in anisotropic rocks, using the isotropic Biot/Gassmann formula, leads to formal errors, because the bulk modulus does not appear, in a natural way, within the anisotropic P-wave velocity. This updated edition is now current as of 2014.

Understanding Seismic Anisotropy in Exploration and Exploitation