Development plans for Midway-Sunset Field in California include a reservoir model and extensive mapping to optimize field development. Steam injection will be used to optimize flushing of the high gravity oil. Recovery of four inch conventional core provided evidence of zones containing cobbles which could impact production and reserve calculations. Thin shaly lenses were also encountered in core which could constitute permeability barriers. The normal logging program was not able to resolve the cobbles or sufficiently identify the shale lenses. A new approach was warranted to provide a solution to the location and volume of cobbles present and to better distinguish permeability barriers.