ENTRAINED HYDROCARBONS PERIPHERAL TO THE AVAK IMPACT STRUCTURE, AND SOME SPECULATIONS ON OIL AND GAS MIGRATION IN THE BARROW AREA, NORTHERN ALASKA

The Avak Impact Structure is a subsurface and seismically identified feature of the Barrow subsurface subsurface in Northern Alaska. The circular crater as at about the shallowest part of the east-plunging Barrow Arch, which is the focus of most ma jor North Slope hydrocarbon accumulations. The Sikulik, East Barrow and South Barrow gas fields are peripheral to the Avak crater. Hydrocarbons fluids include dark, heavy oil, condensate, thermally derived natural gas, methane hydrate gas and non-hydrocarbon helium. These varous kinds of fluids which have migrated into the Barrow reservoirs suggest that this area has multi-phasic filling history.