This paper, describes the effort to justify, document, and confirm proven, unproven, undeveloped, and bypassed remaining oil and gas reserves in West Delta Block 84 Field; at one time an orphaned field off the coast of Louisiana. The methodology used for the evaluation provides an insight into how to quickly and efficiently identify worthwhile and economic marginal properties, even with incomplete or missing information. This methodology is being used as a part of the development of an expert system for the evaluation of marginal and/or orphaned wells, reservoirs, and fields. West Delta Block 84 is located off the coast of Plaquemines Parish, Louisiana, near the mouth of the Mississippi River in about 20 ft of water. Conoco discovered it in 1955 with the drilling of the SL 2551 No. I well to a total depth of 14,500 ft. It has produced over 9.8 MMSTB of oil and 21 BCF of gas. It was shut in for a period of almost ten years while languishing in and out of bankruptcy court from 1990 to 2000, and was actually, orphaned by the state at one point during this time. Available data was organized and pieced together for the field, but was still lacking in completeness. As in most cases dealing with older marginal fields, an ability to deal with missing and incomplete information was necessary to complete the analysis.