梨树断陷沙河子组致密砂岩孔隙结构演化模式

Evolution model of pore structure of dense sandstone in Shahezi Formation of Pear Fracture

综合利用岩石薄片、扫面电镜、铸体薄片、压汞等资料分析对梨树断陷沙河子组致密砂岩的储层特征、成岩作用、成岩演化以及孔隙度演化进行研究。沙河子组经历的成岩作用包括压实作用、胶结作用、溶蚀作用等。其中破坏性成岩作用主要有压实作用、胶结作用;建设性成岩作用主要是溶蚀作用。压实作用使储层孔隙度减小21.1%,方解石胶结使原生孔隙减少12%左右,溶蚀作用使岩石孔隙增加5%左右。本区钙质胶结物有效地保护原生孔隙免遭后期机械压实和构造作用的破坏。

Through the comprehensive integration of thin sections,scanning electron microscopy,casting thin slice,mercury penetration,study and analysis the reservoir characteristics,diagenesis and porosity evolution of the dense sandstone in Shahezi Formation of Pear Fracture. The diagenesis experience of Shahe Formation includes compaction,cementation,dissolution,etc.The destructive diagenesis mainly include compaction and cementation;Constructive diagenesis is dissolution. The compaction reduced the porosity of reservoir by 21.1 %,the calcite cementation reduced the primary porosity by 12 %,and the dissolution increased the porosity of rock by 5 %. Calcareous cementation in this area effectively protects the primary pores from later mechanical compaction and structural damage.