Oilfield Technology correspondent, Gordon Cope explains how although combining enhanced oil recovery with carbon sequestration sounds like a win-win situation, significant hurdles stand in the way.

Anthropogenic CO₂

CO₂ emissions from gas plants are minor when compared to the volumes emitted by coal-fired electricity plants, steel mills and cement plants. One method of capturing GHGs at these types of facilities is known as oxy-fuel combustion, where pure oxygen is mixed with the fuel. This produces a flue gas of pure CO₂, which can then be easily captured. Most facilities use atmospheric oxygen for combustion, however, which results in a flue gas composed of a complex mixture of nitrogen, oxygen, CO₂ and other gases. In order to capture the CO₂, complex modules, including amine absorbers and cryogenic coolers, are used to separate the GHG from its benign cousins. Once it is separated, the CO₂ must be transported in trucks or dedicated pipelines to the oilfield.

Saskatchewan’s Weyburn field, operated by Cenovus, was one of the first fields to use manmade CO₂ for EOR. Since 2000, the company has been injecting 120 million ft³/d into the oilfield. Weyburn gets its CO₂ from a North Dakota coal gasification plant located 320 km south, across the US border. The gasification plant receives US$ 30 million per year for otherwise worthless gas, and Cenovus has the opportunity to recover an additional 130 million bbls. of oil. Other similar projects are either underway, or planned:

Husky Energy, based in Calgary, is capturing CO₂ at its 130 million l/year ethanol plant in Saskatchewan. The project captures 250 t/day of CO₂ and ships it by truck to nearby heavy oilfields, where it is injected in order to lower viscosity and increase flow to wells.

Koch Nitrogen Company altered a fertiliser plant in Enid, OK, so that 680 000 tpy could be captured during the ammonia manufacturing process. Since 2010, the CO₂ has been transported 225 km to Golden Trend and Sko-Vel-Tum fields near Oklahoma City where it is injected in EOR floods.

Air Products is working with Valero to upgrade two of the latter’s existing steam methane reformers (SMRs) at their refinery in Port Arthur, TX. The system will capture approximately 1 million tpy from the SMR flue gases, then transport the gas to an EOR flood operated by Denbury Energy. The system is under construction, and capture is expected to scale up through 2013.

Shell Canada will install a system to capture approximately 1.2 million tpy of CO₂ at its Scotford facility near Edmonton. The facility upgrades bitumen mined at its oilsands facilities in Ft. McMurray. The CO₂ will be transported by pipeline and injected at a depth of 2 km. The project is expected to be operational by the end of 2015.

Part 1 of this article can be reached here.

Part 3 of this article will be available soon!

Adapted by David Bizley from an article in the September 2013 issue of Oilfield Technology. Sign up for a free trial here.

Read the article online at: https://www.oilfieldtechnology.com/drilling-and-production/19092013/what_can_you_do_with_co2_part_2/