Use and Abandonment of Surface Impoundments for the Disposal of Oil-Field Produced Waters: ABSTRACT

Abstract

Surface impoundments, or sumps, are utilized for the disposal of oil-field produced water through percolation and evaporation in California's San Joaquin basin. Environmental concerns have resulted in increased regulation of sumps. Surface disposal of produced waters into unlined sumps is permitted where the quality of the produced water meets the stated criteria in the applicable basin plan as regulated by the local regional water quality control board. In the San Joaquin Basin, surface disposal is initially governed by the Tulare Lake basin plan (5D). A basin plan permits disposal into sumps of produced waters which do not exceed a maximum electrical conductivity, chlorides content, or boron content in areas which overlie useable groundwater. If the produced water exceeds any one of the maximum constituent levels, regulation of surface disposal passes to Title 23, California code of Regulations, sections 2,510-2,601 (subchapter 15). Subchapter 15 regulates the use and abandonment of lined surface impoundments designed to dispose of produced water through evaporation. Subchapter 15 requires the operator to conduct a site hydrogeologic characterization, install a groundwater monitoring system, and construct and enclose the surface impoundment in accordance with specified criteria. Sumps can be utilized in areas which do not meet the criteriamore » of the appropriate basin plan, or subchapter 15, where the operator demonstrates that surface percolation of the produced waters will not degrade underlying useable groundwater. Abandonment of unlined sumps includes removal and disposal of all free liquids, analysis of sludges and soils beneath the sumps, removal of contaminated sludges and soils, analysis of soils after removal of contaminated sludges and soils, backfilling of the sump, and revegetation of the site.« less