Considerable Technical, Regulatory and Cost Barriers to Storing CO2 in North Sea Oil and Gas Fields
Michael Tholen (mtholen@ukooa.co.uk) is Economics and Commercial Director of the UK Offshore Operators Association (UKOOA). Reducing CO2 emissions to meet its international obligations is a major concern in the UK. Here Mike sets out the UKOOA view on the feasibility of using North Sea oil and gas fields to store CO2 captured from onshore power stations.
Background
A number of oil and gas companies have studied the feasibility of capturing or sequestering carbon dioxide emissions from onshore sources, such as power stations, and storing it in depleted North Sea oil and gas fields, but have generally found it to be uneconomic.
Technically, it can be done. Sequestration is already practised in the United States on land, though it requires fiscal incentives to be attractive. Offshore in Norway in the Sleipner gas field, CO2 is removed from the produced natural gas stream on the platform, to improve the natural gas quality, and is re-injected for storage. Removal and reinjection of the CO2 was an integral part of the field’s overall development planning and economics, and the offshore production facilities were specifically designed for the purpose. In addition, reinjection at Sleipner is into a saline aquifer and not into the reservoir. BP has also begun a similar project in the Algerian desert.
Sleipner’s Production Facilities were Specifically Designed for CO2 Separation and Reinjection
Hurdles
Capturing CO2 from an onshore location and transporting it offshore for reinjection through existing oil and gas installations is an entirely different matter. In the North Sea it will require significant investment in new infrastructure both on and offshore, including substantial retrofitting of installations, where there are weight and space limitations.
A further hurdle is the legality of transferring carbon dioxide, officially designated a “waste” product, from one location to another for disposal offshore, which is not allowed under current international law (OSPAR and the London Convention). However, this is being re-examined.
Injecting carbon dioxide into fields could help recover more oil from maturing reservoirs, but not all fields are suitable candidates for this technique. The process of “enhanced oil recovery” (or EOR) is already practised offshore in various forms so using carbon dioxide for EOR, where practicable, will only work at the margins.
Given the state of maturity of the UK North Sea with many fields now approaching the end of their commercial lives, the success of using carbon sequestration as an EOR technique would depend entirely on technical viability, timing and field economics.
Capturing carbon dioxide and storing it under the seabed in the North Sea is not a magic answer to the UK’s rising emissions. Nor should it be seen as a convenient solution to maximising recovery of the UK’s oil and gas resources. There are considerable technical, regulatory and cost barriers which are still to be addressed with economic and fiscal implications.