This Small Business Innovation Research (SBIR) Phase I project will explore improved imaging of subsalt oil and gas reservoirs by incorporating converted wave energy into the seismic migration process. It is difficult to obtain high-quality earth images - necessary in contemporary reservoir development and exploration - in complex subsalt geologic structures. In such regions, conventional seismic technology, using compressional wave data without accounting for converted waves, may incorrectly position geological features, or otherwise not image them at all. 3-D seismic imaging is dependent on successful parameterization of the wave propagation phenomena with asymptotic Green's functions generated by ray tracing or finite-difference traveltime calculation. To determine the feasibility of imaging with converted waves, a petrophysical analysis of subsalt reservoir environments will be coupled with realistic elastic synthetic modeling of seismic wave propagation. The synthetic data will be compared to the results of elastic ray tracing to determine how the elastic ray tracing can effectively parameterize the important converted wave propagation effects. Phase II would involve development of a converted wave imaging algorithm seamlessly integrated with a standard imaging algorithm, so that the more expensive converted wave imaging calculations need only be carried out in small target areas. Subsalt oil and gas reserves in the Gulf of Mexico are costly to produce and therefore require sophisticated and detailed 3-D seismic imaging. This seismic imaging technology is expected to be applied to exploration and reservoir development in geological environments of this kind.
