Natuna D-Alpha Gas Utilization To Increase Oil Dan Gas Recoveries In Indonesia

Abstract

Indonesia has Initial Oil in Place (IOIP) of 70 BSTB which most of it located in Sumatera. Around 30% had already been produced from primary recovery and the rest will be the main target for EOR project.
Aside from oil as national energy source, Indonesia has a large gas resources that come from conventional and unconventional gas. Indonesia has a huge CBM resources as it is the sixth biggest in the world with 453.3 TSCF. CBM production can be increase using Enhanced Coal Bed Methane Recovery (ECBM).
Natuna D-Alpha is a large gas field with estimated Initial Gas in Place (IGIP) of 222 TSCF with composition 71% CO2, 28 % CH4, and 1% others. Previous published Natuna development plans involve separation of CO2 from Natuna gas, those plans treat CO2 as an impurity that need to be dispose. Separation process for that huge fraction of CO2 need advanced technology and extremely costly and these are the reason that for 55 years this field have not been developed.
A new Natuna field development scenario is proposed in this paper. Natuna is not hydrocarbon reservoir but CO2 reservoir. This large CO2 must not be treated as an impurity but as a valuable resource that can be used as EOR and ECBM injection fluid. Natuna gas will be transported either using pipelines or shipped to Sumatera where the gas will be injected in oil fields as EOR fluid and CBM fields as ECBM fluid. This study predicts that oil recoveries can be increase up to 19.17 BSTB and gas recoveries can be increase up to 218.84 TSCF, these recoveries only include fields in Sumatera if they are produced for 30 years according to our scenario.