Hydrocarbon Accumulation Law Research Of Fuyu Reservoir In Weixing Oilfield

Songliao basin is an important oil and gas producing areas in our country, Weixing O ilfield is located in the northern Songliao Basin, Fuyu reservoir is the main oil-bearing formation, has a good potential of exploration and development, but because of the influence of factors: do not have a clear understanding of sandstone distribution and enrichment of oil and water law is not clear, which seriously restrict the next step exploration development of Fuyu oil layer, there is an urgent need for study on reservoir forming law of the system. This paper is based on the core, well logging, mud logging, 3D seismic and regional geological data of the Fuyu oil layer in Weixing O ilfield, by the guidance of oil and gas accumulation theory,using the research method of combining geology, Sedimentology and geochemistry, makes a detailed analysis of reservoir type and distribution law of oil and water, sums up the main controlling factors of oil and gas reservoir and its accumulation mode. The main conclusions are as follows:1)Fuyu reservoir in Weixing O ilfield mainly developed nearly NStrending faults under the condition of the southeast slope structures and low ratio of the sand and formation, fault lithologic reservoir, a small amount of structural lithologic reservoir and lithologic reservoir under the condition of river sand body matching control; 2)O il and gas are distributed in high position of single fault step zone,antithetic fault terrace on both sides of fractured fault zone and local high points inside the inversion type fault zone on the plane;In the vertical direction,oil and gas distributed in FⅠreservoir and FⅡ reservoir under the influence of physical property difference of microfacies, central transporting advantage and stepped migration of oil and gas.;3)summarizes the main controlling factors of hydrocarbon accumulation, oil source correlation shows that the oil from the three Zhao sag K1qn1 source rocks; carrying faults formed dominant channel of oil and gas migration; reservoir forming process and the physical property difference of sedimentary microfacies control the selective filling of oil and gas; rsource rock pressure is the main power of oil and gas discharge/source reservoir butt into Fuyu reservoir; oil and gas migration and accumulation in the Fuyu oil layer controlled with paleo structure; the reverse fault footwall and fault concentrated belt controls the oil and gas enrichment area; 4) on the basis of structure, reservoir, reservoir forming and oil and water comprehensive research, the oil and gas reservoir forming model of Fuyu reservoir in Weixing Oilfield was established:at the end of Mingshui Formation, Xujiaweizi Syncline area in Sanzhao sag K1qn1 source rock generated oil through the source fault entered into the Fuyu reservoir under the action of overpressure,then,was for lateral migration in advantage pathway consisted of carrying faults matching sand body, finally, accumulated in the positive structural trap in the slope area. Under the guidance of the accumulation model, we can predict 4 types of 108 favorable target area for oil and gas enrichment, submited 5 recommended wells, and point out the direction of next efficient development.