The Ignik Sikumi test featured the injection of a mixture of carbon dioxide and nitrogen over a 12 day period and the well was then backflowed in a depressurization mode for 21 additional days. As reported by DOE, methane was produced immediately at the start of the backflow period, increasing in abundance for two days, and then the produced-gas composition stabilized. Carbon dioxide and nitrogen abundance dropped from injection percentages at initial backflow to relatively low percentages in less than two days. In the later part of the depressurization phase of the project, the well was operated at pressures below the equilibrium conditions for methane hydrate, which represents a critical data set to further calibrate gas hydrate production computer simulations. The Ignik Sikumi depressurization test results have also provided invaluable insight to the design criteria for an extended gas hydrate depressurization test in Alaska.

The USGS participated in many phases of this work, including originally identifying the test site, which was based on almost 30 years of USGS geologic studies on gas hydrates in northern Alaska.  USGS supported the Ignik Sikumi test with detailed geologic and geophysical studies of all the sites considered under this effort, and has published detailed descriptions of these sites.  USGS also participated in the downhole logging, formation testing, and well geochemical sampling program.  The USGS is also analyzing gas and water samples collected from the well production stream, which is critical to determine the effectiveness of the carbon dioxide – methane exchange process.

 

• Department of Energy (DOE) News Release
• DOE-National Energy Technology Laboratory (NETL) Project Website