CBM drilling starts at Wainwright

Test drilling for coalbed methane near the village of Wainwright on the Chukchi Sea coast is underway. On June 11 the Alaska Oil and Gas Conservation Commission issued a permit to drill the Wainwright No. 1 well 900 feet from the north line and 2,278 feet from the east line of section 24, township 15 north and range 32 west, Umiat meridian. Drilling operations have begun, USGS co-project chief Art Clark told Petroleum News on June 13.

The U.S. Geological Survey, the U.S Bureau of Land Management and Arctic Slope Regional Corp. are involved in drilling the well, with USGS as the operator. The drillers are using a lightweight drilling rig that was barged to Wainwright from the central North Slope last August.

“We are thinking of a total (well) depth somewhere between 1,500 and 2,000 feet,” Clark told Petroleum News in March.

The well forms part of a multi-year project to test the potential for the use of coalbed natural gas as an energy source in some rural Alaska villages. The project team drilled a test well at Fort Yukon in 2004 and another test well at Franklin Bluffs in the central North Slope in 2005.

At Wainwright coal-bearing strata probably extend down to a depth of between 1,500 and 2,000 feet, although coalbed methane production is unlikely in the permafrost zone that probably extends from the surface down to a depth of about 1,000 feet, Clark said. Whenever the well encounters a coal seam, the team will bring a coal sample to the surface to conduct a gas desorption test, he said. If the test result is favorable, the drillers will use the hollow drill rod to pressure test the seam for parameters such as permeability and gas storage capabilities.

Upon completion of the drilling, if there appears to be a viable gas resource, the drillers will set a 2.5-inch PVC well targeting a specific coal seam. The well would be used to monitor the pressure and temperature in the coal over the winter.

The next step might be another drilling program in 2008 to test the production characteristics of the coal.

The 5.25-inch Wainwright well will be cored continuously to its total depth. Those cores will provide information about the subsurface geology — the nearest well to Wainwright is about 25 miles away.

The team had planned to start drilling at the end of May but delayed operations to allow more time for snow to melt at the drilling site, Clark said. The plan is to complete the work in time to barge equipment from Wainwright in July, if necessary. In addition, early knowledge of the drilling results would enable additional equipment required to be shipped on the North Slope barge that departs from Seattle in mid to late-July.

—Alan Bailey