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This paper was prepared for the Improved Oil Recovery Symposium of the Society of Petroleum Engineers of AIME, to be held in Tulsa, Okla., March 22–24, 1976. Permission to copy is restricted to an abstract of not more than 300 words. Illustrations may not be copied. The abstract should contain conspicuous acknowledgment of where and by whom the paper is presented. Publication elsewhere after publication in the JOURNAL paper is presented. Publication elsewhere after publication in the JOURNAL OF PETROLEUM TECHNOLOGY or the SOCIETY OF PETROLEUM ENGINEERS JOURNAL is usually granted upon request to the Editor of the appropriate journal provided agreement to give proper credit is made. provided agreement to give proper credit is made. Discussion of this paper is invited. Three copies of any discussion should be sent to the Society of Petroleum Engineers office. Such discussion may be presented at the above meeting and with the paper, may be considered for publication in one of the two SPE magazines.
Concern has recently been expressed that the discharge of drilling fluids and cuttings from offshore oil and gas exploration and production wells may cause adverse environmental effects. Laboratory studies using various organisms show these materials to generally be relatively nontoxic. Rapid dispersion and dilution, measured during discharge of drilling fluids and cuttings to seawater, explain the lack of long-term effects in areas with 20 to 40 years of petroleum operations. This indicates that offshore discharge is an environmentally acceptable method for disposal of drilling wastes.
During the drilling of offshore exploration and production wells, drilling fluids and cuttings are usually discharged to the surrounding waters. This practice was followed at most of the 19,000 or more wells drilled to date in U.S. coastal and offshore waters.
With the accelerated OCS leasing program, concern has been expressed by program, concern has been expressed by some as to possible adverse effects of such discharges on marine life.
In this paper we review briefly
drilling practices,
the composition of drilling fluids,
bioassays conducted by Chevron Oil Field Research Company on selecteddrilling fluids,
bioassays on drilling fluids and their components as reported in the literature,
observations of marine life and measurements for chemicals and turbidity made during cuttings and fluids discharges,
observations of marine life in areas where drilling has occurred for long periods of time, and
a comparison of fluid and cuttings discharges with sediment inputs from rivers and storm-resuspended near shore and sea bottom sediments.
