TECTONIC CHARACTERISTIC AND HYDROCARBON RESOURCE POTENTIAL IN THE NORTH SLOP BASIN OF ALASKA,THE ARCTICC

The North Slope Basin of Alaska was a superimposed basin developed during the time range from Palaeozoic through Mesozoic to Cenozoic, and filled with marine and/or nonmarine clastic deposits and marine carbonate rocks since Carboniferous. Structures in NWW-NW-trending and nearly EW-trending dominate the region, The region has experienced four major phases of structural evolution as follows:the Ellesmerian orogenic movement during pre-Middle Devonian; the passive margin phase from Late Devonian to Middle Jurassic;the rifting phase from Middle Jurassic to Early Crataceous; and the Brookian orogenic movement during Late Crataceous. Two potential source rocks have been discovered in the basin:one is the Triassic and Jurassic-Crataceous oil-prone shale and another is the gas-prone shale of basin facies. The most important reservoirs include the Permian-lower Triassic nonmarine and deltaic clastic deposits, lower Triassic and lower Crataceous neritic sands, Carboniferous Lisburme Group of carbonate platform and Mississippian Endicott Group of nonmarine sands. Structural traps and structural-stratigraphic traps were predominant in the basin, usually with high quality seals. A large proportion of the hydrocarbons has been produced from the Ellesmerian reservoir,which still has rather high potential for future exploration. Undiscovered resources mainly distributed in the north part of the basin. It is noted that the structure plays in the Chukchi coast and Brookian mountain front and the stratigraphic traps in the deep-water area of the north part of the basin are potential prospects for future exploration.