塔北隆起英买2地区奥陶系油气成藏特征及富集规律

Hydrocarbon accumulation and enrichment rule of Ordovician in Yingmai-2 area, northern uplift of Tarim Basin

为厘清英买2地区奥陶系碳酸盐岩油气成藏史与主成藏期,探索油气富集规律,借助流体包裹体岩相学及温度特征分析,从油气主成藏期、构造、断裂及储层研究入手,解剖油气富集成藏主控因素间的时空匹配关系。研究表明,英买2地区奥陶系储层发育晚加里东—早海西期、晚海西期和喜马拉雅期等3期烃包裹体,反映储层经历了3次不同期次、不同强度的油气充注,且以晚海西期的中质油气充注为主;研究区油气富集受控于主成藏期构造背景下断裂与储层的时空匹配;北北西向、北西向走滑断裂带及北东向逆冲走滑断裂带对储层发育和油气运移与调整均起到了重要的控制作用;3组不同期次断裂带交会区是油气富集区,其优质储层和优势输导体系等成藏控制因素与主成藏期匹配良好。在此基础上,对油气富集接替区进行了预测。

In order to confirm the oil and gas accumulation rules of Ordovician carbonate reservoir in Yingmai-2 area,through the analysis of petrography and temperature features of fluid inclusion, the time-space relation for reservoirforming conditions was studied from the aspects of accumulation stages, structure, fault and reservoir. The result shows that the Ordovician reservoir in Yingmai-2 area experienced three hydrocarbon inclusions stages, including the late Caledonian-early Hercynian, the late Hercynian and the Himalayan stage. These three stages represent the oil and gas charging of three different periods and intensities, and the main stage is the intermediate oil and gas charging in late Hercynian. Under the background of structure, the oil and gas accumulation of Yingmai-2 area were controlled by space-time matching of fracture and reservoir during the main reservoir-forming period. Reservoir development and oil and gas enrichment were dominated by superimposition of fractures in three different stages. NNW and NW strike-slip fault and NE thrust-strike-slip fault played an important role in hydrocarbon migration and adjustment. The faults of three different periods met to form the fault interference zone, which can control the development and enrichment of oil and gas reservoir. On this basis, the replacing area of oil and gas enrichment of Yingmai-2 area was predicted.