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基于岩心观察、铸体薄片鉴定、储集层荧光、油气地化特征以及测试资料分析,研究四川盆地中部侏罗系自流井组大安寨段致密油富集高产控制因素。川中侏罗系大安寨段介壳灰岩、泥质介壳灰岩以及致密灰岩均含油;不仅介壳灰岩中溶蚀孔和裂缝含油,而且致密灰岩基质孔(微裂隙和晶间孔)也均含油,呈现大面积普遍含油特征,其是油气井低产周期长的主要原因。在大面积普遍含油基础上,来自上三叠统须家河组的天然气为川中低幅度无水大安寨段致密灰岩储集层中石油运聚提供了动力,驱动致密灰岩基质孔中分散原油的运移聚集,使得高气油比井分布较多的川中西部构造石油富集程度较高,而川中东部受华蓥山大断裂的影响,断裂普遍断穿大安寨段,导致储集层中的天然气沿断裂运移到大安寨段以上地层富集或者散失,储集层缺乏天然气驱动,导致其油气富集程度不如西部。
Based on the observation of cores, the identification of cast thin slices, the fluorescence of reservoirs, the characteristics of oil and gas geochemistry and the test data, the factors influencing enrichment and yield control of tight oil in Daanzhai Section of Jurassic Ziliujing Formation in central Sichuan Basin were studied. The Jurassic Daanzhai Member of the Central Sichuan Basin is rich in oil from both crust limestone, argillaceous limestone and tight limestone. Not only the dissolution pores and fractures are oil-rich in the karst limestone, but also the matrix pores (microcracks and intergranular pores) in the tight limestone Oil, showing a large area of universal oil features, which is the main reason for the low production cycle of oil and gas wells. On the basis of a large area of common oil, natural gas from the Upper Triassic Xujiahe Formation provides a driving force for the migration and accumulation of oil in the tight limestone reservoirs in the Daanzhai section of central-Sichuan low-velocity anomalies, driving the dispersion of crude oil in the matrix pores of the tight limestone Of the migration and accumulation, so that high gas oil well distribution more wells in the central and western Sichuan higher oil enrichment, and the eastern Central Sichuan Basin by the Huayingshan fault, the fault is generally broken Daanzhai section, resulting in the reservoir Natural gas moves along the fault to the above Daanzhai section for enrichment or loss, and the reservoir lacks natural gas drive, resulting in less oil and gas accumulation than the west.