Application of AVO Types in the Depiction of Seismic Lithologies
Gordon W. Van Swearingen and Roger A. Young
eSeis Inc., Houston, Texas
Discerning various lithologies from seismic has long been a goal of the explorationist. Until recently, the seismic interpretation of lithologies has been limited to velocity variations of shale and not shale, or “sand”. This method was further limited by the changing relationship of the shale and “sand” velocities with variations in depth, age, porosity, fluid content and geopressure.
By using a newly expanded version of AVO Types in conjunction with lithology/fluid and porosity cross-plots, seismic lithologies can be expanded from shale and not shale to a variety of options specific to the basin/play type. A Gulf Coast example illustrates the differences between shales, sands with both wet and gas filled porosity, tight sands and calcite cemented siltstones. A Green River Basin example illustrates the differences between tight sands, gas sands, and coals.
AAPG Search and Discovery Article #90032©2004 GCAGS 54th Annual Convention, San Antonio, Texas, October 10-12, 2004