苏里格东区致密气储层成岩储集相分类及特征

Classfication and characteristics of reservoir diagenetic facies for tight gas reservoir in eastern area of Sulige

苏里格东区致密气藏储层受多期沉积、成岩及构造等作用影响,成岩过程中压实和胶结作用强烈,成岩作用复杂,储层具有孔隙空间小、孔隙结构复杂等特点。文中在分析成岩储集相形成主控因素的基础上,通过对该区盒8上、盒8下、山1、山2段成岩储集相的孔隙度演化过程进行反演,得出不同储集相各成岩阶段的孔隙度演化模式,据此将成岩储集相分为4类,并对分类成岩储集相的岩性、物性特征进行了详细定量描述。在此基础上,对分类成岩储集相的微观孔隙结构特征进行分析,得出该区整体上微观孔隙结构细小,非均质性较强,但Ⅰ,Ⅱ类成岩储集相明显具有相对较好的孔隙结构及渗流、储集特征,为该区致密气藏筛选优质储层提供了有效的含气信息。

The tight gas reservoir in the eastern area of Sulige is influenced by multi-period sedimentation,diagenesis and structure.It endures strong compaction and cementation during diagenesis process in which the diagenesis is very complex.The reservoir is characterized by small pore space and complex pore structure.On the basis of the analysis of main controlling factors for the formation of reservoir diagenetic facies,the porosity evolution model in different reservoir diagenetic facies stages is established by the inversion of porosity evolution in Upper He 8,Lower He 8,Shan 1 and Shan 2 Members in this area.The reservoir diagenetic facies are divided into 4 classes and the lithology and physical property of classified reservoir diagenetic facies are described in a detailed and quantitative way.Besides,the fact that micro-pore structure is small and heterogeneity is serious on the whole in the area can be found through analyzing the characteristics of microscopic pore structure for the classified reservoir diagenetic facies.Class Ⅰand Class Ⅱ of reservoir diagenetic facies have comparatively better pore structure,percolation and reservoir characteristics,which can provide an effective gas-bearing information for screening the high-quality reservoir in the tight gas reservoir.