02 June 2011

ANS well to test methane hydrate technologies

May 18, 2011
Nick Snow
OGJ Washington Editor
WASHINGTON, DC, May 18 -- A fully instrumented well that will test innovative technologies to produce methane gas from hydrate deposits has been safely installed on Alaska’s North Slope and will be available for field experiments as early as next winter, the US Department of Energy’s Fossil Energy Office announced on May 17.

FEO said the well—the result of a partnership of ConocoPhillips and FEO’s National Energy Technology Laboratory—will test a technology that involves injecting carbon dioxide into sandstone reservoirs containing methane hydrate. Laboratory studies indicate that the CO2 molecules will replace the methane molecules in the solid hydrate lattice, resulting in the simultaneous sequestration of CO2 in a solid hydrate structure and production of methane gas, FEO said.

Recently completed operations include the acquisition of a research-level suite of measurements through the subpermafrost hydrate-bearing sediments, it indicated. The data confirm the occurrence of 160 ft of gas-hydrate-bearing sand reservoirs in four separate zones, as predicted, and provide insight into their physical and mechanical properties.

An array of downhole pressure-temperature gauges were installed in the well, as well as a continuous fiber-optic temperature sensor outside the well casing, which will monitor the well as it returns to natural conditions following the drilling program, FEO added.

It said in coming months, field trial participants will review the data to determine the optimal parameters for future field testing. Current plans are to reenter the well in a future winter drilling season, and conduct a 1-2 month program of CO2 injection and well production to assess the efficiency of the exchange process.
Following those tests, the remaining time available before the spring thaw (as much as 40 days) may be used to test reservoir response to pressure reduction in the wellbore. This alternative methane-production method, "depressurization," recently proved effective during short-term testing conducted by the governments of Japan and Canada at a site in northwestern Canada, according to FEO.

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