关键词: 早白垩世, 断裂体系, 构造样式, 构造演化, 油气勘探, 陆西凹陷

Abstract: Luxi Sag, Kailu Basin has experienced multiple periods of tectonic movements and is tectonically complex and diverse. In view of the unclear pattern of tectonic evolution in this area, the early Cretaceous fault system, tectonic evolution process and hydrocarbon accumulation pattern of Luxi Sag were clarified with tectonic analysis, stratigraphic stratigraphy and other research methods, seismic profile analysis and coherence slicing technology. The study results showed that, since the Early Cretaceous, the tectonic styles of Luxi Sag mainly included half-graben structure, rollover anticline and fault block. The tectonic evolution was divided into four periods according to the formation time of tectonic style, including the initial rifting period (the sedimentation stage of lower Jiufotang Member), the subsidence and depression period (the sedimentation stage of upper Jiufotang Member), the stable subsidence period (the sedimentation period of Shahai Formation), and the backward shrinkage period (the sedimentation period of Fuxin Formation). As indicated by the results of the study, the fault-block traps formed in the early stage and the compression-shear tectonic movement in the late stage were the main controlling factors for the hydrocarbon accumulation in tectonic traps. Periodic tectonic movements are favorable for oil and gas migration and the formation of large-scale structural oil and gas reservoirs. The multi-stage fan developed in the subsidence and depression period provided reservoir space for hydrocarbon accumulation, and the multi-stage tectonic movement was conducive to oil-gas migration and the formation of large tectonic oil-gas pools. The results of the study provide a basis and guidance for determining the favorable exploration targets for East Slope, Luxi Sag.

Key words: Early Cretaceous, fault system, tectonic style, tectonic evolution, hydrocarbon exploration, Luxi Sag