Sleipner Vest CO2 Disposal, CO2 Injection Into A Shallow Underground Aquifer

This paper describes the problem of disposing large amounts of CO 2 into a shallow underground aquifer from an offshore location in the North Sea. The solutions presented is an alternative for CO 2 emitting industries in addressing the growing concern for the environmental impact from such activities. The topside injection facilities, the well and reservoir aspects are discussed as well as the considerations made during establishing the design basis and the solutions chosen. The CO 2 injection issues in this project differs from industry practice in that the CO 2 is wet and contaminated with methane, and further, because of the shallow depth, the total pressure resistance in the system is not sufficient for the CO 2 to naturally stay in the dense phase region. To allow for safe and cost effective handling of the CO 2 , it was necessary to develop an injection system that gave a constant back pressure from the well corresponding to the output pressure from the compressor, and being independent of the injection rate. This is accomplished by selecting a high injectivity sand formation, completing the well with a large bore, and regulating the dense phase CO 2 temperature and thus the density of the fluid in order to account for the variations in back pressure from the well.