东营凹陷南部缓坡带沙四段滩坝砂储层分布及成藏主控因素

Reservoir distribution and main factors influencing hydrocarbon accumulation of beach-bar sandstone in the Sha4 of Shahejie Formation,gentle slope belt,Dongying Depression

沙四段滩坝砂岩油气藏是东营凹陷南部缓坡带油气勘探的重要类型之一,由于滩坝砂储层分布复杂、油气成藏规律不清,长期以来制约着勘探工作的深入。通过高分辨率层序地层学以及沉积动力学分析,对东营凹陷南部缓坡带沙四段滩坝砂储层分布进行了综合研究,确定了储层分布规律及控制因素;通过典型油气藏解剖和输导体系研究,明确了滩坝砂体油气成藏控制因素。研究结果表明:古地形与浪基面控制了滩坝砂发育范围,古水动力控制了滩坝砂的相分异,基准面的升降变化控制了滩坝砂的叠置样式。油源是滩坝砂油气成藏的基础,断裂输导和异常压力是滩坝砂油气富集成藏的必要条件。

The beach-bar sandstone reservoir in the fourth member of Shahejie Formation is one of the main petroleum exploration targets at gentle slope belt in Dongying Depression. The complex reservoir distribution and the unknown petroleum accumulation rule greatly restrict the exploration progress for the beach-bar reservoir. According to the theory of high-resolution sequence stratigraphy and sedimentary dynamics,the reservoir distribution of the Es4 beach-bar sandstone at the gentle slop belt in Dongying Depression was researched comprehensively, and the distribution rule of the high-quality reservoirs and its controlling factors were recognized. After the analysis of typical oil reservoir and the research on transportation system, main factors influencing hydrocarbon accumulation of the beach-bar sandbodies were realized. The results show that the reservoir distribution were controlled by palaeotopography and wave-built surface,the facies segregation was respectively controlled by palaeohydrodynamic condition, and superimposed patterns of the beach-bar sandstone were controlled by the elevation and subsidence of the datum level. Oil source was the basis of oil-gas reservoir forming, and fault and overpres-sure were the necessary conditions of the oil-gas accumulation of the beach-bar sandstone.