American Institute of Mining, Metallurgical, and Petroleum Engineers Inc. Abstract After a detailed study of 12 years' performance of the Fullerton Clearfork performance of the Fullerton Clearfork Unit, a special study group recommended major operating changes which will increase ultimate oil recovery 22 million barrels. New techniques included a simplified waterflood model and a statistical approach to measure reservoir continuity. Evaluation of alternate plans with these tools indicated the plans with these tools indicated the need for infill drilling and a closer spaced pattern. Introduction Location and Geology The Fullerton Field is located in west Texas in Andrews County, 50 miles north-west of Midland as shown on Figure 1. Geologically, the field is located in the northeastern part of the Central Basin Platform Area, and lies in a north-west-southeast trend of Permian carbonate production stretching for more than 100 miles. Figure 2 is a structure map which shows the northwest-southeast trending, anticline with approximately 400 feet of relief on top of the Clearfork formation. There are two prominent structural domes on this feature with the North Dome being much the larger of the two. The Fullerton structure continues northward from the Unit boundary and is productive in the adjacent, but separately prorated Union Field. Discovery was in 1942 and was followed by rapid development during the next five years with 565 wells completed by 1947. Development continued throughout the 1950's and 1960's with sporadic development up to the present time.