Steve Metcalf, BJ Services Co.
San Andres producers in several areas of Gaines County, Texas are limited on stimulation injection rates due to the proximity of potential water producing intervals. The San Andres is a dirty dolomite formation with a bottomhole temperature of approximately 135_F. Usage of acid to stimulate the formation is desirable, but given the low injection rate restrictions, diversion and penetration of the acid into the formation are difficult to accomplish. Prior treatments using rock salt for diversion resulted in most of the salt falling into the rat-hole. Recently, success has been achieved utilizing a viscoelastic acid diversion system and a chemically retarded acid system pumped in alternate stages. Injection rates have been held to 3 BPM or less, with pressure increases from diversion being observed. Initial production responses have been from 2 to 7 times more oil and 2 to 5 times the water.