Reservoir, Sealing and Trapping of CO2 Storage in Cycle I and II, Sarawak Basin, Malaysia

Summary Carbon emission has been increasingly alarming due to higher industrial activities. In conjunction with a net zero carbon emission policy by 2050, research has been done to promote CO2 underground storage. The offshore Sarawak region had been explored throughout the decade to achieve an enhanced understanding of the basin. The offshore Sarawak Basin has promising storage characteristics which are displayed evidently from wells data and seismic lines. Cycle I and II portrays complex lithofacies which affect porosity and permeability. Cycle I and II analogous to the Nyalau Formation exhibits the lower and upper shoreface facies. The average storage depth is above 1000 m with a fairly warm sedimentary basin of a geothermal gradient >43°C. These conditions allow CO2 to be stored in a dense phase which will maximise the storage volume and reduce upward migration. The trapping of CO2 in these areas improved with intraformational seals of Setap Shale and Lower Cycle III as regional seals. The trapping mechanisms allow CO2 to migrate between pores and dissolve into formation water beneath the seal which is laterally extensive within the basin to prevent upward migration. The characteristics described above portrays good reservoir and trapping potential for the CO2 storage.