ESTIMATING THE POTENTIAL FOR FUTURE OIL SPILLS FROM TANKERS, OFFSHORE DEVELOPMENT, AND ONSHORE PIPELINES

Abstract

ABSTRACT This paper summarizes historical spill statistics and describes techniques and equations that can be used to predict possible future oil spillage from marine tankers, offshore petroleum development facilities, and cross-country pipelines. These techniques would be expected to provide worst-case estimates because they do not account for continuing improvements in technology, operating procedures and safety measures. Information compiled from the literature on world-wide tanker casualty spills during 1969–972 indicates that such spills can be expected to occur within 50 miles of land an average of once in every 1,000 vessel port-calls or about once in every 50 vessel-years of operation. The average size of these casualty spills (within 50 miles of land) is 7,100 bbl and the average spill rate is about 87 bpmb (bbl per million bbl) transported. Oil spill data from the U.S. Geological Survey are presented for outer continental shelf (OCS) petroleum development operations during 1966–1975. This information indicates an average spill rate from all causes (pipeline accidents, blowouts, fires, etc.) of about 72 bpmb produced. Oil industry cross-country pipeline spill data for Western Europe (1968–1974) and Canada (1965–1972) show that 1.1 to 1.5 spills can be expected from all causes per year per 1,000 miles of pipeline. The mean spill rate (obtained for Western Europe only) was 3.6 bpmb of throughput.