FORNEBU, Norway – Aker Solutions and various major operators are collaborating in a joint industry project on subsea gas separation.
According to the company, studies on injecting carbon-dioxide (CO2) to boost recovery and extend the lives of offshore fields have focused on separation of the ‘back-produced’ CO2 from the wellstream on existing platforms.
The cost, however, makes the concept economically unattractive.
The new JIP, supported by Total, Pertamina, Equinor and the CO2 Capture Project (CCP), involving BP, Chevron and Petrobras, is seeking to identify required membrane qualities for a subsea gas and CO2 separation process.
Doing so would minimize pre-treatment requirements and avoid the need for additional large processing modules.
Aker Solutions has developed new concepts for subsea processing of well streams from CO2-flooded oil fields, in which CO2-rich gas is separated, compressed, and re-injected into the reservoir. The hydrocarbon-enriched gas is then routed to the topsides production facility.
Gas separation subsea must, however, be performed with sturdy membranes, and the presently qualified operating range for relevant membrane materials do not match the optimal operating conditions for gas separation on the seabed, the company explained.
Testing is therefore necessary to determine membrane performance under these conditions.
The SINTEF research institute in Norway will test different membrane qualities under relevant conditions related to pressure, temperature, gas composition and production rates.
In addition, technical and economic engineering studies will assess the technology concept based on the results.
Main aims of the project are to:
- Qualify membrane qualities suitable for bulk separation of CO2 in a typical subsea process
- Confirm technical and economic use of subsea processing for offshore CO2 EOR (enhanced oil recovery), in combination with reinjection and storage of CO2.
Aker Solutions delivered the world’s first subsea gas compression system to Equinor for the Åsgard field in the Norwegian Sea, and the equipment has operated with no unplanned downtime since the installation in 2015.
Subsea gas separation technology could be applied in combination with subsea gas compression technology to facilitate offshore handling of CO2 for EOR, Aker Solutions said.