Bioremediation Pit Closures

Michael E. McAllister

Coastal Oil & Gas Corporation (COG) is committed to sound resource management. We are challenged to minimize corporate environmental liability while employing the best control mechanisms, procedures and processes which are scientifically sound and economically feasible. We feel that our pit closure project being conducted within our Altamont/Bluebell Utah, and Tatum, New Mexico operational areas is an excellent example of this commitment.

In 1990, through a series of property acquisitions, change in operatorships and oil field operations COG had inherited 152 production pits of assorted sizes, and containing unknown quantities of high paraffin crude, water and sludge. Recognizing the need for corrective action we evaluated several pit closure techniques. It was determined that the use of naturally occurring hydrocarbon eating bacteria was the best available technology to achieve a goal of cost effective closure without long term environmental liabilities.

The bacterial process allowed COG to achieve pit closure by treating the hydrocarbon contamination on-site. The process by-products are carbon dioxide, natural cell protein and water. Therefore replacing the hydrocarbon with items completely compatible to the environment.

COG designed the pit closure program to be completed within three (3) years. The pits are to be closed and replaced with a standard size lined "emergency pit" maintained free off liquids. We started our closure process with locations on BLM and/or BIA land. The program was expanded to those locations, as designated, with the potential for ground or surface water contamination. To date 140 pits have been completed with the remaining 12 scheduled for closure in 1994.

This project has provided the following positive considerations:

-- The closing of hydrocarbon contaminated production pits

-- The treating of the materials on-site

-- Not increasing environmental liabilities by hauling material to a landfill

-- Installation of lined "emergency pits" free of liquids

-- Reducing liabilities while protecting the environment

During the project COG recognized the additional benefit of reclaiming an average of 100-150 barrels of sellable product per pit. Therefore the cost of our closure project was offset by approximately 40% per year.

It is our position that this project clearly demonstrates that a company's profit motives and environmental protection are compatible goals.

AAPG Search and Discovery Article #91020©1995 AAPG Annual Convention, Houston, Texas, May 5-8, 1995