Paper: Waterflooding the Grayburg Formation On The J.L. Johnson AB Lease Experience in The Johnson Field

The Grayburg formation in the Johnson field, Ector County, Texas, is a more complex reservoir than originally believed. Poor response from waterflooding the J. L. Johnson "AB" lease with 40-acre five-spots led to development with ZO-acre line-drive patterns. This caused a substantial production increase. Infill drilling has lead to the discovery of random, anhydrite-filled sections which act as barriers to flow. They are probably interconnected and may be the cause of poor response to injection on wide spacing. Anhydrite barriers may exist both in other parts of the Johnson field and in surrounding fields. These barriers could play an important role in determining how other waterfloods are designed.