Using Outcrop-Based 3D Geocellular Model as Seismic Benchmark: Prestack Seismic Modeling of Grainstones in Lawyer Canyon (Permian) Outcrop,Guadalupe Mountains, New Mexico

Janson, Xavier¹, Hongliu Zeng¹, Charles Kerans¹, Fred Wang¹, Sergey Fomel¹ (1) The University of Texas at Austin, Austin, TX

Three dimension seismic data have become a primary tool for building reservoir models and forecasting reservoir volumes at all stages of the reservoir's life. In particular, one of the important issues in the characterization and modeling of carbonate reservoir strata that remains to be effectively addressed is the seismic characterization of touching-vug pore systems and the integration of seismic information into fluid-flow models. To address this problem, we built poststack and prestack synthetic seismogram from accurate outcrop-based 3-D geological models. The geological model is built for a Permian (lower San Andres) carbonate sequence exposed in the Lawyer Canyon outcrop, New Mexico, that provides an excellent analog of ramp-crest grainstones having both interparticle porosity and touching-vug porosity. Post-stack seismogram calculated by 3-D exploding reflectors methods are initially used to calibrate the sensitivity of the seismic methods to velocity changes due to moldic pore and to assess the mapability of these two pore type system using acoustic inversion. Using the assumption that the effect of moldic pore compared to inter-particle pore on seismic velocity primarily affects compressional velocity, we investigate the sensitivity of the AVO response of these grainstone bodies using pre-stack synthetic modeling. Because of the different Vp/Vs between the grainstone with moldic pores and the grainstone with interparticle pores, we can map the two grainstone 3D bodies directly from the synthetic pre-stack seismic volume.