开鲁盆地陆西凹陷早白垩世地层构造演化及勘探潜力

开鲁盆地陆西凹陷经历多期构造运动,构造复杂多样,针对该区构造演化规律不清的问题,运用构造解析、层序地层学等研究方法,通过地震剖面分析和相干体切片技术,明确了陆西凹陷早白垩世断裂体系与构造演化过程及油气成藏模式。研究结果表明:早白垩世以来,陆西凹陷构造样式主要包括半地堑构造样式、滚动背斜构造样式、断块构造样式。依据构造样式形成时间可划分出4个构造演化时期:初始裂陷期(九佛堂下段沉积期)、沉降拗陷期(九佛堂上段沉积期)、稳定沉降期(沙海组沉积期)、回返萎缩期(阜新组沉积期)。研究结果认为,早期形成的断块型圈闭和晚期压扭性构造运动为构造圈闭成藏的主控因素,沉降坳陷期发育的多期扇体为油气成藏提供储集空间,多期次构造运动有利于油气运移和大规模构造油气藏的形成。研究结果为确定陆西凹陷东陡坡的有利勘探方向提供了依据和指导。

Early Cretaceous Stratigraphic Evolution and Exploration Potential of Luxi Sag,Kailu Basin

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.