Cased Hole Saturation Logging To Identify Bypassed Oil Opportunities - Case Studies From The Sarawak Basin

Murphy Oil Company operates a number of mature oil and gas fields in the Sarawak Basin, Malaysia. It has been utilizing a new generation pulsed neutron tool (“PNT”) to help track production related fluid changes and identify bypassed oil. This paper summarizes case studies from 2 wells, using the PNT tool for saturation logging and interpretation, and the production benefits identified. Field A results include the identification of a displaced gas-leg and a basal swept zone. The well was successfully recompleted in the original gas-leg with production of 1000 BOPD and low GOR. Limited water production commenced several months later, consistent with the PNT results. Oil movement to the gas cap was identified accurately using the PNT log as confirmed by well testing and production. Field B was logged over 3 reservoirs and two recompletion targets were identified. Reservoir B1 has a full oil-leg below the original GOC with no evidence of water-sweep. Reservoir B2 is thin-bedded with ambiguous hydrocarbon fill; logging results indicate that this zone is oil-bearing. It is planned to complete both zones as oil producers utilizing a single production string configuration with zonal selectivity, increasing field production and accessing additional, previously undeveloped, reserves.