北极阿拉斯加北坡盆地地质构造特征与油气资源潜力

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

    • 摘要: 阿拉斯加北坡盆地位于北极圈北部一个古、中、新生代叠合盆地,主要发育石炭系以来海相—非海相碎屑岩、海相碳酸盐岩。盆地的主体构造呈NWW—NW向和近EW向,经历了前中泥盆世埃尔斯米尔造山、晚泥盆世—中侏罗世被动边缘、中侏罗世—早白垩世裂谷以及晚期的布鲁克斯造山和前陆4个构造演化阶段。盆地主要发育生油为主的三叠系和侏罗—白垩系页岩、生气为主的盆地相页岩2套烃源岩,以二叠系—下三叠统非海相和三角洲相碎屑岩、下三叠统和下白垩统浅海相砂岩、石炭系台地相碳酸盐岩和密西西比阶埃迪克特群非海相砂岩为盆地主要储层。其盖层分布广泛且封盖条件良好,以构造和构造-地层复合圈闭为主。盆地大部分石油产自埃尔斯米尔储层,石油和天然气待发现资源量大,主要位于盆地北部,其中楚科奇海岸和布鲁克斯山前的构造发育带以及北部深水地层圈闭是未来油气有利勘探区域。

       

      Abstract: 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.

       

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