This case study demonstrates predictions of lithology and porosity variations for a high acoustic impedance gas sand. The approach combines three techniques to estimate and interpret an acoustic impedance and Poisson ratio term by: 1. generating with AVO analysis a Normal Incidence (NI) and Poisson Reflectivity (PR) from 2. applying a recursive inversion method to independently generate estimates of acoustic impedance from NI and Poisson ratio from PR; and 3. utilizing a crossplot method to simultaneously display and as a color-coded section portraying variations in lithology, porosity and pore fluid. This approach overcomes limitations in stack seismic inversion to discriminate porosity from lithology. It also extends application of AVO to sands with exceeding shaleThe targeted channel sands lie beneath a Cretaceous shalechalk section (-14 000 feet depth). These channel sands interfinger with debris-flow facies to reach a combined thickness of 160 ft, with reservoir net pay of 69 ft. Maximum porosity is 22% with pay reservoir quality to 9%. The clean channel facies provide excellent reservoir quality, while intergranular detrital clay in the debris-flow facies reduces reservoir quality. The inversion discriminates these facies. Near the most productive wells, shows a significant drop from the background. Also, the crossplot display reveals that these sands occur within a canyon-like feature. With this definition of geometry and seismic facies, we have the potential to predict well performance in areas where interfingered sands are below seismic resolution.