First ever field pilot on Alaska's north slope to validate the use of polymer floods for heavy oil EOR.
Project Description
The field pilot test will be implemented in the Milne Point Field (MPF) which includes 35,744 acres and is located approximately 30 miles northwest of Prudhoe Bay on the Alaska's North Slope (ANS). The Milne Point Field consists of four oil pools, starting from the top: Ugnu, Schrader Bluff, Kuparuk River and Sag River, while the project reservoir is in the Schrader Bluff formation. The Schrader Bluff formation extends between 3400 ft to 5200 ft true vertical depth subsea (TVDss). This late cretaceous age formation is divided into two stratigraphic intervals, namely O sands and N sands. O sands are subdivided into OB and OA, while N sands have subintervals NF, NE, ND, NC, NB, NA. The structure of the pool is homocline with 1-2° dip from East to Northeast. Schrader Bluff O sands were deposited 70 million years ago from marine shoreface and shelf deposits. They consist of fine-grained, quartz-rich sandstone interbedded with siltstone and mudstone. The overlying N sands were deposited within wave-dominated shoreface and deltaic systems. Upward coarsening is evident with mudstone and siltstone dominating the lower portion of this interval. There is no evidence of free gas accumulation within the Schrader Bluff formation, but complex fault blocks have compartmentalized this pool (Bidinger and Dillon 1995). The project reservoir is in the Schrader Bluff NB-sand, an unconsolidated sandstone. The project reservoir has generally excellent petrophysical properties, with porosity ranging from 31%-35% and permeability ranging from 100 to 3,000 mD. The average thickness of the reservoir is about 15 ft and the reservoir temperature is about 70°F. API gravity of oil is about 15 with in-situ oil viscosity of 330 cP in the project area. Preliminary laboratory and simulation studies indicated that polymer flooding has great potential to enhance oil recovery from the Schrader Bluff heavy oil reservoirs (Seright 2010, 2011), yet no field test has been performed to date in Alaska. In fact, no large-scale polymer flood of a heavy oil and other unconventional resources has occurred to date in the entire United States, although it has been tested and implemented in other countries, such as Canada and China. Initial scoping studies suggest that successful implementation of polymer flooding could increase heavy oil recovery by 50% on the North Slope of Alaska and increase America's oil reserves by tens of billions of barrels.