Oil Pools Distribution Of Fuyu Reservoir In Chaochang Area Of Songliao Basin

Fuyu reservoir is the objective interval of exploration and production in Chaochang area of Songliao basin. And confirming its reservoir characteristics, accumulation and distribution of oil pools, is of great practical significance in the expansion of the scale of proven reserves and oil field, and deepening the understanding of reservoir geology.In this paper, first of all, the necessary conditions for hydrocarbon accumulation are investigated in several aspects, such as structural features, reservoir sedimentation, and source-reservoir- cap combination for Fuyu reservoir in the Chaochang area of Songliao basin. Secondly, the main reservoir types and their characteristics are identified through dissecting typical oil and gas pools. Thirdly, the macro patterns of hydrocarbon migration and five accumulation models of different structural belts are established by comprehensively studying the accumulation time, the migration momentum and the migration pathway of petroleum. Finally, oil pools distribution of Fuyu reservoir is summarized on the basis of the key factors controlling hydrocarbon accumulation.The main research results are as follows:Four typical pool types, including anticline pool, updip sandstone pinchout pool, nose- and fault-lithologic complex pool, are identified in Fuyu reservoir. On the whole, the lithologic and the structural-lithologic complex reservoir is the vast majority.Fuyu reservoir hydrocarbon accumulation occurred chiefly in three periods, including the end of Nenjiang formation, the end of Mingshui formation and the end of Tertiary. In each period,“top source-foot reservoir”model of vertical migration and accumulation formed in the effective range of hydrocarbon source rocks as a result of pressure difference; five major accumulation models in different structural belts, covering anticline type, long-term monoclinic type, nose-lithology complex type, early monoclinic-late syncline type and depression type, shaped on account of the potential difference, pressure difference.The key factors controlling hydrocarbon accumulation are suggested that:①source rock maturity and anticline uplift with a good space-time configuration is a crucial condition for petroleum accumulation;②sandbody and fault with the organic combination constitutes transporting system of petroleum migration and accumulation; ③sandbody and post structural belts with different match shows the characteristics of different oil and gas accumulation.Pools distribution of Fuyu reservoir is showed that:①Vertically, FⅠand FⅡ-top sandstone groups are the main oil-bearing layers in Chaochang area;②Horizontally, anticline oil and gas pools are mostly developed in three anticlines, such as Chao Yanggou, Fan Shentun and Chang Chunling anticline; updip sandstone pinchout pools and fault-lithologic complex reservoir pools largely in the northwestern wing zone of Chaoyanggou terrace and the surrounding slope zone of Wangfu depression, furthermore in the well-84-syncline; nose-lithologic complex pools primarily in such noses as Bohetai, Dayushu and Yumin structures.