The unique properties of CO2 can be used to enhance oil production as a value-creating supplement to permanent CO2 storage. The CO2 will mix with the oil and make the oil flow more easily, thereby increasing the production of oil. CO2 will be produced with the oil and must be separated and reinjected into the reservoir. Existing offshore platforms will normally not be able to handle the increased CO2 production without significant modifications requiring long shutdowns. Aker Solutions, in cooperation with Equinor and MAN Energy Solutions and partly financed by the CLIMIT program, have evaluated the proven Åsgard Subsea Compression technology for service with a CO2 rich gas mixture. This application may become an enabling solution for offshore CO2 Enhanced Oil Recovery (EOR).

The solution is a simplified subsea system for pre-treatment of the well stream to minimize the CO2 produced to an offshore platform. Oil and gas is separated subsea and the whole gas phase is reinjected (CO2 and hydrocarbons) to minimize the amount of CO2 produced to the existing facility. SUBCOMP has included reservoir simulations, evaluation of required operating conditions to reduce the topside CO2 exposure and impact on export gas quality, evaluation of compressor functionality with large variations in gas composition and flow rates, design of the subsea processing plant, and material evaluations. Co-author: Dr. Dirk Büche, MAN Energy Solutions Schweiz AG.