鄂尔多斯盆地林镇地区延安组油气成藏规律

Hydrocarbon Accumulation of Linzhen Yanan Formation in Ordos Basin

运用储层地球化学手段,分析林镇地区延安组中新发现的多个高效油藏的油气来源、运移路径与动力,同时系统研究了储层、盖层和圈闭等成藏条件,并探讨了油藏的成藏机制。结果表明:林镇地区延安组油藏原油主要来源于其下伏的延长组长7烃源岩。油气在高剩余压力推动下由长7烃源岩向上驱动至长6、长4+5段中,而后在浮力的推动下,以深切河谷做为运移通道,油气继续向上运移到延安组延10段至延9段中,进入延安组河道砂体,沿储层砂体发育且砂体连通性较好的河道砂体横向运移进入林镇地区构造或构造-岩性圈闭中成藏。研究结果对完善河流相油藏成藏理论和指导油气进一步勘探具有指导意义。

Reservoir geochemical test is used to analyze the hydrocarbon sources,migration paths and agents of multiple new-discovered oil reservoirs in Linzhen Yanan formation. The corresponding hydrocarbon accumulation conditions are also systematically discussed,including reservoir,cap-rock and trap,etc. Research demonstrates that the hydrocarbon in Linzhen Yanan formation is mainly sourced from the underlying Yanchang Chang7source-rock. The hydrocarbon migrates from Chang7source-rock into Chang6 and Chang4 + 5through the driving of high remaining pressure. Then,due to the drive of buoyancy,the hydrocarbon continues to upward migrate into Yan10 and Yan9by taking the deep-incised valley as migration path,and the hydrocarbon finally migrates into the channel sandboties of Yanan formation. The hydrocarbon laterally migrates along the channel sandboties with well-developed reservoir and relatively favorable connectivity and accumulates in Linzhen structure or structure-lithology traps. Research may provide a practical reference for completing fluvial-facies hydrocarbon accumulation theory and guiding further hydrocarbon exploration.