Abstract

The Cannery Loop field is located on the Kenai Peninsula near the mouth of the Kenai River. The area was unitized in 1978 by Union Oil Company of California (Unocal), the original operator of the Cannery Loop Unit. The following year, the field was discovered by Unocal’s Cannery Loop Unit 1 well. This well tested the Tertiary Tyonek reservoirs, and first production was established in 1988. Marathon Oil Company became the successor unit operator in 1994 and has since drilled an additional 10 wells in the field. Production of dry gas from the Cannery Loop Unit is from three clastic accumulations in the Tertiary Kenai Group, which includes the nonmarine, fluvial, Miocene, and Pliocene sandstone reservoirs of the Tyonek, Beluga, and Sterling Formations. As of December 2011, cumulative field production is approximately 180 BCF of gas. The majority of current production is from the Beluga sands, but both the Sterling and Tyonek intervals still produce. Initially, the Cannery Loop area was drilled as a northern extension of the Kenai field, but subsequent interpretation of a transverse east–west-trending normal fault and pressure isolation lead to the unitization and separation of Cannery Loop from the Kenai field. The Cannery Loop structure is interpreted as a relatively low-relief, northeast-southwest-trending anticline that forms four-way structural closure. Most production is structurally controlled, and some stratigraphic traps exist. Produced gas is biogenic in origin and is predominantly composed of methane gas that developed in situ from the associated interbedded coals.