Distinguished Instructor Short Course 1999

Philip Schultz

Spirit Energy/Unocal

The Seismic Velocity Model as an Interpretation Asset


Philip Schultz A velocity model can have enduring and growing interpretive value, beyond its initial creation to optimize the seismic image. The 3D velocity model is often built carefully with a combination of geophysical and geological input, because of the accuracy demands placed on it by the requirements of depth imaging. As such, this model becomes an increasingly effective interpretive tool. This course addresses the ways in which the interpreter should participate in the development of the velocity model, and underscores its interpretive value with numerous case study examples.

After a brief introduction and preview of the day, the course begins with a comprehensive case study example, where interpretive input was key to development of all phases of the refined velocity model for depth imaging and depth conversion, and where the interpretation itself was refined in conjunction with the development of the velocity model. Following this showcase study, and to complete the morning session, the course embarks on a concise overview of the general model building methodology. The course will review the types of geological settings requiring varied approaches to velocity model building, and will highlight those model-building aspects where interpretive input is normally essential.

In the afternoon, the course focuses on over a dozen case studies, supplied by major, independent, and national oil companies, where some interpretation or exploration problem was solved by attention to the velocity model. The studies follow the thought processes of the interpreter in his or her approach to the problem. The case studies run from the simple to the complex, cover soft rock and hard rock environments, and touch on imaging, depth conversion, fault location, well placement, lithology, anisotropy, and other velocity-related issues. All studies carry the common theme that the velocity model was a key element in the development of the geological interpretation. Moreover, the interpreter participated actively in the development of all the velocity models.

Who Should Attend?

The interpreter excited by the prospect of participating actively in the velocity model building process, and who wishes to pursue aggressively the additional advantages offered by using the velocity model in the interpretation should attend this course, as well as the manager and supervisor seeking familiarity with velocity-related tools for developing a geological model.