江陵凹陷新沟嘴组下段储层地质特征

GEOLOGICAL CHARACTERISTICS OF LOWER XING GOUZUI FORMATION AT JIANGLING DEPRESSION

江陵凹陷新沟嘴组下段储层是一套湖泊三角洲－浅湖滩坝砂体，砂体类型有三角洲平原分流河道砂体，三解洲前缘水下分流河道砂体及三角洲前缘水下分流河口砂坝等，岩石类型为成分成熟度较低的岩屑长石砂岩和长石砂岩，并含较多的粘土矿物和硬石膏、方解石、白云石胶结物，压实和胶结是使原生孔隙降低的主要成岩作用，而发生在油气大量生成 期的溶解作用则使较多的次生孔隙形成，储层物性受岩石结构如粒径，分选等控制，也受胶结物含量及溶解作用等控制。

The reservoirs of Lower Xing Gouzui Formation at Jianling Depression are a set of lacustrine delta-shallow lake sandbodies, which include lacustrine delta plain river sandbodies, delta front subaqueous sandbodies and shallow lake sandbodies, etc.The rocks are lithic arkose and arkose which are in low composition saturation and has high clay content,anhydrite,calcite and dolomite cements. Compaction and cementation are the main processes which reduced the primary porosity. On the other hand,the dissolution in the saturation of organic matter increased the porosity by creating secondary pores. The factor controlled the reservoir properties are the textures of the rocks such as grain size and sorting,cement content and dissolution.