关键词: 深层致密油, 断陷盆地, 源内自生自储, 近源岩性地层油藏, 远源构造油藏, 输导体系, 营城组四段, 白垩系, 双城断陷, 松辽盆地

Abstract: By comprehensively utilizing seismic data and core analysis testing data such as inclusion homogenization temperature，rock pyrolysis，and reservoir properties，the types，distribution characteristics，and accumulation stages of tight oil reservoirs of the fourth member of Cretaceous Yingcheng Formation（Ying-4 member） in Shuangcheng fault depression of Songliao Basin were analyzed，and the main controlling factors for tight oil accumulation were studied from four aspects：source rock evaluation，reservoir characteristics，tectonic activities，and transport system. The results show that：（1）The distribution pattern of tight oil reservoirs of Ying-4 member in Shuangcheng fault depression of Songliao Basin is as follows：from the central trough to the slopes on both sides，there are lithologic reservoirs within the source，near source fault-lithologic reservoirs，stratigraphic reservoirs，and far source structural reservoirs. The reservoir is one-stage hydrocarbon accumulation， and the main accumulation satge is from the late sedimentary period of Yaojia Formation in Late Cretaceous to the early sedimentary period of Nenjiang Formation（80-78 Ma）.（2）The lacustrine mudstone and oil shale developed in the lower submember of Ying-4 member（K₁yc⁴）in the study area have great potential for oil and gas generation. The central depression is the center of hydrocarbon generation and expulsion，with high hydrocarbon generation and expulsion intensities of（20-300）×10⁴ t/km² and（5-53）×10⁴ t/km²，respectively. The fan delta conglomerate sandstone reservoirs developed in the upper K₁yc⁴ has a large thickness and good continuity. The front sand bodies extend into the lake，with an average porosity of 11.4% and an average permeability of 0.95 mD. Among them，relatively high-quality reservoirs with porosity greater than 8.0% and permeability higher than 0.85 mD are favorable targets for tight oil enrichment. Deep traps of various types formed at the end of Quantou Formation in Early Cretaceous，structure during the main accumulation stage was weak，which is conducive to the formation and preservation of oil reservoirs. The multi type three-dimensional transport system composed of faults，unconformities，and connected sand bodies is the main pathway for oil and gas migration， promoting the convergence of oil and gas towards the slopes on both sides.（3）The tight oil reservoir accumulation in the study area is controlled by the coupling of“source rock-fan delta sandbody-transport system”，and is distributed in a ring-shaped pattern around hydrocarbon generating troughs，with characteristics of large-scale distribution and local enrichment. Three reservoir accumulation models are developed，including“reservoir overriding source rock，and they connect with reticular-blanket transportations，oil accumulate within the fan delta” in center depression，“source and reservoir close proximity，fault sandstone matching，and migration along the fault step”in eastern slope，and“source and reservoir separation，“Y”- shaped migration and accumulation，and enrichment in tectonic highs”in western steep slope. Fan bodies enclosed by mudstone or in contact with mudstone interlayers，fault-lithologic and stratigraphic traps near oil source faults，and anticline and fault anticline traps near oil source faults are favorable exploration targets for the central depression，eastern slope，and western steep slope，respectively.

Key words: tight oil in deep layer, faulted basin, self-souce and self-reservoir within source, near source lithologic-stratigraphic reservoir, far source structural reservoir, transport system, the fourth member of Yingcheng Formation, Cretaceous, Shuangcheng fault depression, Songliao Basin