Enhanced oil recovery - polymer. Gulf injects polymer for better water distribution in Yates sand

Experimentation with several enhanced oil recovery methods in the North Ward-Estes field in Ward and Winkler Counties, Texas, has prompted Gulf Oil Exploration and Production Co. to begin a full-scale polymer flood in the southern portion of that field. Phase I of the multimillion dollar project was well under way in late January. Phase II is tentatively scheduled to begin in March. Phase I involves 3 sections (1920 acres) of Gulf's Hutchings Stock Association lease. Ninety-six producing wells and 96 injection wells have been drilled on 10-acre spacing in 20-acre, 5-spot patterns. At the beginning of the project there were 157 active wells on the 3 sections - 95 producers and 62 injectors. For the project, 25 producers were converted to injectors and 9 infill injectors were drilled to replace plugged and abandoned wells. Polymer injection in Phase I began November 3, 1981. In late January, polymer had been pumped down approximately half the 96 injection wells. The procedure for treating each injection well with an acrylamide monomer/catalyst solution is described.