四川盆地复兴地区侏罗系凉高山组致密砂岩储层特征及其主控因素

Tight sandstone reservoir characteristics and main controlling factors of Jurassic Lianggaoshan Formation in Fuxing area,Sichuan Basin

四川盆地复兴地区侏罗系凉高山组致密砂岩储层近期表现出良好的勘探潜力,以X井和Z井为代表,均获得测试工业油气流。为了进一步明确复兴地区侏罗系凉高山组致密砂岩储层发育特征及控制因素,以该套砂岩为研究对象,通过岩心观察、普通薄片鉴定、扫描电镜观察及综合多种分析测试结果,从岩石学特征、沉积相、物性特征和成岩作用类型等多个方面对研究区目的层进行了精细刻画。研究结果表明,凉高山组致密砂岩储层总体表现为低孔低渗储层,储集空间以原生残余粒间孔发育为主,孔隙半径为10~50μm,喉道宽度为2~10μm。根据成岩作用对储层物性的影响,将压实作用、部分胶结作用归为破坏性成岩作用,溶蚀作用、构造作用和绿泥石的膜状胶结作用归为建设性成岩作用。本次研究明确了三角洲前缘水下分流河道微相最利于凉高山组砂岩储层的发育,而长石的溶蚀作用、构造成因的微裂缝和以绿泥石为胶结物的胶结作用对凉高山组致密砂岩储层的物性具有改善作用,沉积-成岩综合作用是四川盆地复兴地区凉高山组致密砂岩优质储层发育的重要条件。

The tight sandstone reservoir of Jurassic Lianggaoshan Formation in Fuxing area,Sichuan Basin has shown good exploration potential recently.Represented by wells X and Z,the tested industrial oil and gas flows have been obtained.In order to further understand the development characteristics and control factors of tight sandstone reservoirs of Jurassic Lianggaoshan Formation in the Fuxing area,through core observation,ordinary thin section identification,scanning electron microscope observation and multiple test results,the target layer in the study area is analyzed in detail.The results reveal that the tight sandstone reservoir of Lianggaoshan Formation is generally characterized by low porosity and low permeability,and the reservoir space is dominated by inorganic pores with a pore radius of 10-50μm.Throat width is 2-10μm。According to the influence of different diagenesis on reservoir physical properties,compaction and partial cementation are classified as destructive diagenesis,while dissolution,tectonism and cementation with chlorite cementation are divided into constructive diagenesis.This study makes clear that the subaqueous distributary channels of the delta front is the most favorable to the development of Lianggaoshan Formation sandstone reservoir.The cementation with dissolution,tectonism and chlorite cementation can improve the physical properties of Lianggaoshan Formation tight sandstone reservoir.