Andreas Rüger received a B.S. (1991) in geophysics from the University of Karlsruhe, Germany, and an M.S. (1993) and a Ph.D. (1996) from the Center for Wave Phenomena at Colorado School of Mines. He was a Fulbright Scholar in 1992 and recipient of SEG’s J. C. Karcher Award in 1999. He wrote SEG’s Geophysical Monographs Series Number 10, Reflection Coefficients and Azimuthal AVO Analysis in Anisotropic Media. Rüger is now with Landmark Graphics and works on seismic modeling, velocity model building, and meshing.
J. Clarence Karcher Award 1999
Andreas Rüger is being honored with the J. Clarence Karcher Award for exceptional research on analyzing reflection coefficients and seismic amplitudes in anisotropic media. In particular, he has derived simple analytic approximations for reflection coefficients in azimuthally anisotropic media and has related the azimuthal variation of AVO attributes to physical parameters of fractured formations, relationships that allow fractured reservoirs to be characterized by prestack P-wave amplitude.
Biography Citation for the J. Clarence Karcher Award
We have taught dozens of students on two continents, many of whom have done leading-edge research to obtain advanced degrees. What distinguishes
Andreas Rüger within this group is a quality difficult to find even in more mature scientists. Andreas has proved extremely good at almost every aspect of research and applied geophysics—from developing theory to producing computer codes to processing real data. Whatever the problem, we knew that he would usually go far beyond answering the original question.
In Landmark Graphics, where Andreas has been employed since graduating from the Colorado School of Mines, he earned the nickname “spin meister” for pingpong prowess. The main reason Andreas is receiving the J. Clarence Karcher Award is the elegant spin he put on the cumbersome equations for reflection coefficients in anisotropic media. The behavior of reflection coefficients is not easy to analyze even for media that are homogeneous and isotropic on both sides of the interface. The problem becomes much more involved if one or both halfspaces are anisotropic. Wide-azimuth 3-D data over fractured reservoirs contain clear evidence that the azimuthal variation of prestack amplitudes (i.e., azimuthal AVO analysis) is sensitive to the presence of vertical fractures. It was substantially more difficult, however, to understand the relationship between the azimuthal AVO response and the anisotropic parameters describing the fractures. Andreas developed linearized approximations for the anisotropic reflection coefficients and identified the parameter combinations crucial for AVO analysis. These groundbreaking results provide a solid basis for using AVO in fracture characterization.
While solving the reflection/transmission problem for fractured media, Andreas corrected and streamlined approximations for reflection coefficients in simpler models—transversely isotropic with a vertical symmetry axis and even purely isotropic—as well. His beautifully written Ph.D. dissertation, probably the best existing text on reflection coefficients, will soon be published as an SEG monograph.
We were always impressed with Andreas’ ability to persevere through difficult times—both in personal life and research. Maybe this maturity comes from his diverse background. Before entering the geophysical program at the University of Karlsruhe in 1987, Andreas had received a degree in Spanish literature and philosophy at the University of Madrid. He worked on acquisition crews in East Greenland and Kenya and helped build a telephone system in Tanzania in 1988.
While at Mines, Andreas could digest complicated course material, explain it in simple terms to fellow students and, sometimes, to the professor. Andreas’ oral exams never were a one-way street. They would become discussions of intricate technical issues. Andreas would often arrive with comments on the course notes and say, “You may want to fix this part of the derivation...” or “I would probably prove this in a different way...” In fact, the course notes written by one of us (I.T.) for Samizdat Press benefited from Andreas’ suggestions.
Andreas’ versatility has served him well in his work on software applications at Landmark. Burke Angstman, Andreas’ manager, says, “Words such as brilliant, meticulous, logical, exact, thorough, and incredibly responsible have been used at Landmark to describe Andreas. I would add pleasant, willing, and reliable. He has taken on numerous tasks, including the design and coding of an objectoriented ray-tracing framework. This is unique in the industry and will become the basis for a robust, ray-based, migration traveltime solver and a suite of interpretive raytracing tools. Andreas has studied ray propagation algorithms thoroughly and is a leading expert in the field.”
Time will reveal the validity of Burke’s assessment but no time is required to know that this recipient of the J. Clarence Karcher Award is a geophysicist of maturity and accomplishment beyond his years.