History of a Scurry County, Texas, Reef Unit

Underlying part of a several county area in western Texas is the Horseshoe atoll, which will measure about 90 miles across in an east-west direction and about 70 miles from north to south. Producing from the Canyon Reef limestone at approximately 6,700 ft., which is a part of the Horseshoe atoll that underlies Scurry County, is the Sharon Ridge Canyon Unit. The Sharon Ridge Canyon Unit is a pressure maintenance project using fresh surface water injected on a peripheral pattern. The water distribution system is made up of both bare steel and cement lined pipe. A central treating plant is used, and water quality has been maintained at a high level with corrosion controlled effectively. Wells are produced to a high water-oil ratio which means continual water production of a certain amount. The produced water is gathered and returned to the reservoir through its own system. Since commencement of unitized operations the volumetric average reservoir pressure has increased 471 psi from 1,583 to 2,054 psi. Performance to date under the influence of water injection has been very encouraging, and a recovery of twice that predicted without pressure maintenance is expected.