Geology, reservoir engineering and methane hydrate potential of the Walakpa Gas Field, North Slope, Alaska. Final report

• Main Authors: Glenn, R.K., Allen, W.W.
• Language: unknown
• Published: 2011
• Subjects: 03 NATURAL GAS; ALASKA; NATURAL GAS HYDRATE DEPOSITS; GEOLOGY; EXPLOITATION; PROGRESS REPORT; RESERVOIR ENGINEERING; PERMAFROST; WELL DRILLING; SANDSTONES; RESERVOIR TEMPERATURE; RESERVOIR PRESSURE; STRATIGRAPHY; LITHOLOGY; PERMEABILITY; NUMERICAL DATA; Barrow; Methane hydrate; north slope; permafrost; Alaska
• Online Access: http://www.osti.gov/servlets/purl/10142661; https://www.osti.gov/biblio/10142661; https://doi.org/10.2172/10142661

The Walakpa Gas Field, located near the city of Barrow on Alaska`s North Slope, has been proven to be methane-bearing at depths of 2000--2550 feet below sea level. The producing formation is a laterally continuous, south-dipping, Lower Cretaceous shelf sandstone. The updip extent of the reservoir has not been determined by drilling, but probably extends to at least 1900 feet below sea level. Reservoir temperatures in the updip portion of the reservoir may be low enough to allow the presence of in situ methane hydrates. Reservoir net pay however, decreases to the north. Depths to the base of permafrost in the area average 940 feet. Drilling techniques and production configuration in the Walakpa field were designed to minimize formation damage to the reservoir sandstone and to eliminate methane hydrates formed during production. Drilling development of the Walakpa field was a sequential updip and lateral stepout from a previously drilled, structurally lower confirmation well. Reservoir temperature, pressure, and gas chemistry data from the development wells confirm that they have been drilled in the free-methane portion of the reservoir. Future studies in the Walakpa field are planned to determine whether or not a component of the methane production is due to the dissociation of updip in situ hydrates.