U.s. Department of the Interior

Drilling and Testing the Doi041a Coalbed Methane Well, Fort Yukon, Alaska U.s. Department of the Interior

The Yukon Flats basin in east-central Alaska is a 8,500 mi2 basin containing up to 10,000 ft of Cenozoic fill including upper Miocene to upper Oligocene nonmarine coal-bearing lacustrine strata (Kirschner, 1994). CBM potential in the basin was primarily based on a 1994 2 USGS climate studies core hole that was drilled to a depth of 1,282 ft near the village of Fort Yukon at lat 66.55949°N, long 145.20616°W. After setting steel casing through the top 100 ft of Quaternary gravel deposits, the well was drilled through mid-Pliocene to early-Miocene lacustrine, fluvial, and paludal deposits (Ager, T. A., 2005, unpub. data) and penetrated a thick coal bed from a depth of 1,256 to 1,282 ft. When brought to land surface and extracted from the core tube, the coal cores were visibly and audibly degassing to the atmosphere. However, no gas desorption or sampling equipment was available at the site and no analysis of the gas content or chemistry was conducted. Due to concerns about the possibility of a gas blowout, drilling was terminated at 1,282 ft prior to penetrating the full thickness of the coal.