The objective of this project is to develop improved chemical oil recovery options for the Ugnu reservoir overlying the Milne Point unit in North Slope, Alaska.
University of Texas, Austin, TX 78712-1160
The North Slope of Alaska has large (about 20 billion barrels) deposits of viscous oil in the Ugnu, West Sak, and Shraeder Bluff reservoirs. These shallow reservoirs overlie existing productive reservoirs such as Kuparuk and Milne Point. The viscosity of the Ugnu reservoir overlying Milne Point varies from 200 cP to 10,000 cP and the depth is about 3500 ft. The same reservoir extends to the west overlying the Kuparuk River Unit and on to the Beaufort Sea. The depth of the reservoir decreases and the viscosity increases toward the west. Currently, the operators are planning to test cold heavy oil production with sand (CHOPS) in Ugnu, but oil recovery is expected to be low (< 10%). Improved oil recovery techniques must be developed for these reservoirs. Proximity to the permafrost is an issue for thermal methods; thus non-thermal methods must be considered. In the past, gasflood and alkaline-surfactant-polymer methods have been developed for light oils and polymer methods have been developed for medium viscosity oil. Hydrocarbon gases are now available for injection into oil reservoirs to improve oil recovery, but their availability will be limited once a gas pipeline is constructed. Thus, the objective of this proposal is to develop chemical methods to recover oil from the Ugnu reservoir (overlying Milne Point) with a limited use of gas solvents.
This project will identify the applicability of chemical techniques for heavy oil recovery at the laboratory-scale. Project personnel will evaluate mechanisms of heavy oil recovery in many new secondary recovery processes (e.g., alkaline-surfactant, alkaline-surfactant-polymer, and colloidal dispersion gel floods) as well as the sweep efficiency and the microscopic displacement efficiency of these processes. Mechanistic numerical models will be developed for each of these processes to explain laboratory results and determine field-scale implications. Research leading to a successful chemical recovery method could result in the economically viable recovery of many billions of barrels of oil from the Ugnu reservoir without damaging the permafrost. The scientific and technical insight gained from this project can potentially be applied to other heavy oil reservoirs.
This project ended on 3/31/12. All proposed project work has been completed. The final report is available below under "Additional Information".
Final Project Report [PDF-2.90MB]