An Area of Review Variance Methodology

Abstract

Abstract When the Underground Injection Control (UIC) Regulations were promulgated in 1980, by the U.S. EPA, existing Class II (oilfield) injection wells operating at the time that the regulations became effective were excluded from Area of Review (AOR) requirements. EPA has expressed its intent to revise the regulations to include the requirement for AORs for such wells. A Federal Adivisory Committee (FAC) has recommended that AORs for existing wells, not previously subject to that requirement, be performed within five years of promulgation of amended UIC regulations. The FAC has, however, recognized that conditions can exist that make it unnecessary to perform well-by-well AORs and that can allow wells in a basin, producing trend, region or field or a portion of such areas to be exempted from an AOR through a variance program. A methodology for identifying areas that would be eligible for variance from AOR requirements has been developed. The methodology provides for evaluation of an area for variance based upon five criteria. These criteria could be used in any order, singly or in combination, to exclude some or all wells from the AOR process. Wells not excluded by variance would be subject to well-by-well AORs.