济阳坳陷二叠系储集层特征及其控制因素

通过对济阳坳陷二叠系砂岩储集层岩石的压汞实验分析,结合薄片分析与扫描电镜观察,利用能反映储集层孔隙结构特征及渗流性能的参数,分析该区二叠系储集层岩石的储集特征.结果表明,该区二叠系碎屑岩储集层以成分成熟度和结构成熟度均较高的中粗粒及含砾中粗粒石英砂岩为主,属于典型的低孔低渗-特低孔特低渗型储集层;主要储集空间为次生孔隙和裂缝,具有孔喉半径小、分选性和连通性较差、渗流能力较差的孔喉特征;最大孔喉半径是决定其渗流能力的主要因素,反映了次生孔隙的发育对其储集性能的重要性.研究结果还表明.控制该区二叠系碎屑岩储集层发育的主要地质因素是沉积主水道(高能河道或分流河道)的分布型式、酸性水介质溶蚀相的发育程度及构造条件.

Characteristics and controlling factors of Permian reservoirs in Jiyang Depression

Permian formation in Jiyang Depression has good potential for oil and gas exploration. According to thin section, scanning electron microscope and mercury injection analysis, clastic reservoir sandstone is mainly composed of medium to coarse-grained quartz sandstone and gravel-bearing medium to coarse-grained quartz sandstone, has the characteristics of high compositional maturity and texture maturity, and belongs to low porosity and permeability to extremely low porosity and permeability type. The main reservoir space types are secondary pores and fractures. Additionally, the reservoir pore throat structure is characterized by mini pore throat, poor sorting, poor connectedness and poor infiltrating ability. Maximum pore radius is the crucial factor for reservoir infiltrating ability, which reveals that secondary pores have great influence to reservoir quality. Study on controlling factors of reservoir quality reveals that the main controlling factors are distribution style of sedimentary main fluvial channels (distributary channels of delta plain or meandering river channels), solution facies development in acidic aqueous media and favorable tectonic condition.