CO2 Flooding: Its Time Has Come

Significant increases in enhanced oil recovery projects utilizing CO/sub 2/ have been noted in the past 2 years, and CO/sub 2/ pipeline completions will bring on large field applications. Factors in selection of reservoirs for CO/sub 2/ miscible flooding are summarized. The potential for immiscible flooding can be determined by simple laboratory CO/sub 2/ solubility, swelling, and viscosity tests at reservoir conditions. Single-well minitests with logging and coring and single-well huff-n-puff field tests will provide a direct evaluation of CO/sub 2/ in a reservoir where geology, rock permeability, and other properties are not well known. CO/sub 2/ huff-n-puff has produced large quantities of heavy oil at low water-oil ratio in many field projects. It probably will be limited to relatively few fields because steam is usually more available and cheaper, and can be effective in several injection/production cycles. However, use of CO/sub 2/ huff-n-puff as a precursor to an immiscible CO/sub 2/ flood could be an efficient application of CO/sub 2/. 50 references.