Paper: MANAGEMENT OF A MULTI-LAYERED WATERFLOOD USING POLYMER GEL TECHNOLOGY A CASE STUDY

In May 1992, Marathon Oil Company implemented a San Andres waterflood on the Kloh Lease in the Howard-Glasscock Field, Howard County, Texas. The San Andres formation is a multi-layered carbonate reservoir characterized as having moldic porosity enhanced by natural fractures. Water injection into the various intervals was initially managed by mechanical isolation equipment. Due to high permeability zones, water cycling became a major concern. An interwell tracer program was initiated to identify which injection and production wells were in direct communication. Results from the tracer survey indicated the presence of thief zones in the lower injection interval that were responsible for rapid water breakthrough. This paper illustrates how polymer gel technology was used to further manage water injection in a multi-layered reservoir. Six injection wells and five producing wells were treated with polyacrylamide gel. Results from the injection well polymer treatments indicate an initial incremental response of 125 BOPD. Producing well polymer treatments showed an incremental response of 55 BOPD and a reduction in water production by almost 5,000 BWPD.