关键词: 环太平洋构造域, 油气地质, 晚侏罗世—早白垩世, 走滑拉分裂陷盆地, 东北油气区, 中国

Abstract: From Late Jurassic to Early Cretaceous, the northeast part of China entered the continental peripheral structural development stage of the Pacific-rim structural region. There developed a series of strike-slip pull-apart rift basins in the swallow-shaped array. They have the following oil and gas migration and accumulation characteristics. The hydrocarbon source rock of successive deep rift and multistage overlapped rift is large in thickness, good in quality and high in thermal development. The oil and gas storage conditions are desirable with high abundance of oil and gas resources. One of the prominent characteristics for the strike-slip pull-apart rift is that the hydrocarbon source conditions are rapidly becoming poorer towards the two sides from the deep fault groove. Therefore, the high-abundance deep fault groove controls the oil and gas abundance. There develops four compound oil and gas accumulation zones: sag-controlled strike-slip fault belt, deep groove periphery, slop fold belt of slop zone and uplift on the periphery of rift. The oil and gas abundance is of the middle to relatively low degree owing to the strong structural separation and the small scale of the sedimentary system, thus developing a large number of the medium-size and small oil and gas fields. There is a great difference in thermal development degree with a variety of mother rock types. The oil and gas migrated and accumulated in multiple stages with co-existence of oil reservoirs, gas reservoirs and oil-gas reservoirs. The region has experienced multi-stage multi-stage structural movements following the Late Jurassic-Early Cretaceous rifts, leading to multi-stage oil and gas migration and accumulation. The difference is apparent in the ratio of the original and secondary oil and gas reservoirs in each block owing to the difference in the oil and gas migration and accumulation conditions in each block. Therefore, if the blocks and target layers are optimized and selected according to the oil and gas reservoir characteristics in the strike-slip pull-apart rift basins in this region, the reserves will be raised significantly in the future.