APPLICATION OF AN AREA-OF-REVIEW (AOR) CONCEPT TO THE EAST TEXAS FIELD AND OTHER SELECTED TEXAS OILFIELDS
The Underground Injection Control (UIC) regulations of the US Environmental Protection Agency (EPA) require an Area-of-Review (AOR) study for newly drilled or converted Class II injection wells. In Texas, the UIC program is administered by the Texas Railroad Commission. A Federal Advisory Committee (FAC) formed by the EPA recommended, in 1992, that exceptions to the AOR requirement should be allowed for wells in those areas where a variance has been granted because there is sufficiently low risk of upward fluid migration from the injection zone into an underground source of drinking water. The FAC listed conditions that could be considered in determining whether to grant a variance. The University of Missouri-Rolla (UMR), under contract with the American Petroleum Institute, then expanded the FAC AOR variance conditions into an AOR variance methodology. A Department of Energy (DOE) grant to UMR, for which this is the final report, provided for study of the application of the AOR variance methodology to the East Texas field and to other selected Texas oilfields. A final report on the East Texas field portion of the DOE project was submitted by UMR to DOE in 1995. This current final report describes the results of UMR's study of AOR variance opportunities in the Texas Gulf Coast Frio Formation oil producing trend. In the course of this study, AOR variance opportunities were examined for 73 oilfields in nine Texas Gulf Coast counties. It is believed that the combination of well construction and abandonment characteristics plus the presence of sloughing and squeezing shales and porous and permeable sand sink zones provide for the possibility of AOR variances in 57 of the 73 study fields. The remaining 16 fields are ones where the oil accumulations occur in conjunction with shallow salt domes and where geologic conditions are probably too complex to allow field-wide AOR variances. The successful study results can probably be extended to at least 78 additional oilfields in 17 other Frio Formation producing trend counties.
- Research Organization:
- University of Missouri
- DOE Contract Number:
- FG22-94MT94002
- OSTI ID:
- 818831
- Country of Publication:
- United States
- Language:
- English
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An area-of-review variance study of the East Texas field
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