3D seismic reprocessing for geologic interpretation of a permafrost-bearing petroleum system on the North Slope, Alaska

Abstract

The Umiat field on the North Slope, Alaska, contains light oil in the shallow, frozen reservoirs. It is the only known permafrost-bearing oil deposit in the US. Although several studies estimated 1.5 billion bbl of oil and 99 bcf of gas in the Umiat field, there is no commercial production to date. The shallow reservoir intervals in this field are filled up with permafrost (or frozen ground) and gas. Permafrost is affected by the presence of lakes, ponds, and streams, which have appreciable heat capacity. The presence of permafrost, gas, and ice lakes deteriorates the seismic data quality significantly. In this study, we reprocess the 3D seismic data and generate new seismic images that show prominent stratigraphy and structure, some of which were not visible before. The results reveal the presence of shelf-edges with strong amplitude anomalies at the shallow intervals and a structural high at the deep interval.