Application of An Area of Review Variance Methodology For Underground Injection Control Regulations To Fields In Gaines County, Texas

When the Underground Injection Control Regulations were promulgated in 1980, existing oilfield (Class II) injection wells operating at the time that the regulations became effective were excluded from Area of Review requirements. The Environmental Protection Agency has expressed its intent to revise the regulations to include the requirement for Area of Reviews for such wells. A methodology developed for obtaining Area of Review variances has been applied to oilfields in Gaines County, Texas. The work is part of a broader effort to apply the variance methodology throughout areas of the West Texas Permian basin. The work is being conducted under sponsorship of the American Petroleum Institute. The general concept of the variance methodology which has been developed uses basic variance criteria that were agreed to by a Federal Advisory Committee, but expands upon those to provide a greater range of variance options. In this study, the geology and hydrogeology of areas within Gaines County were defined with respect to petroleum production and groundwater occurrence. Oilfields were identified using several databases from the Texas Railroad Commission . Only fields with significant injection were investigated. Ten fields were identified for study. These included Cedar Lake, Flanagan, G-M-K, Harris, Riley North, Robertson North, Russell, Seminole, Seminole East, and Seminole West. The results of the study with respect to the opportunity for variance for injection field in Gaines County are presented. The implications of the Gaines County study for other Permian basin counties are also discussed.