西湖凹陷X气藏花港组H3段储层特征及影响因素

文中通过岩心观察、镜下薄片、扫描电镜、压汞等资料,深入研究了西湖凹陷X气藏花港组H3段储层岩石组分、物性特征和孔隙结构。结果表明:储层岩性主要为长石岩屑砂岩,储集空间主要为残余原生孔和溶蚀粒间孔,属中—低孔渗、非均质性较强储层;孔隙结构具有细小孔隙、细喉道、细歪度、孔喉分选差及连通性差等特征;储层孔喉类型包括粗孔喉、中孔喉、中—细孔喉型以及细孔喉等4种类型;沉积、成岩及构造作用影响储层发育,沉积作用是影响储层孔隙结构的基础,成岩作用类型及其演化是决定储层孔隙结构特征的关键,构造作用是改善储层的途径。研究成果对研究区储层分类评价及下步天然气勘探开发具有重要的指导意义。

Characteristics and influencing factors of reservoir in H3 section of Huagang Formation,X gas reservoir,Xihu Sag

Through the core observation and thin sections,scanning electron microscopy,and mercury injection tests,the petrological compositions,physical properties,and pore structure of the upper section of the Huagang Formation in X gas reservoir,Xihu Sag,were studied.The results show that the lithology of the reservoir is mainly feldspar lithic sandstone,and the reservoir space is mainly residual primary pores and intergranular pores,belonging to heterogeneous reservoir with medium to low porosity and permeability;the pore structure has fine pore,fine throat,skewness,poor throat sorting and poor connectivity,etc.;reservoir pore structure is divided into four categories,coarse pore throat,middle pore throat,middle-fine pore throat,and fine pore throat.It is found that sedimentary,diagenetic and tectonic processes affect reservoir development,and sedimentation is the basis of reservoir pore structure.The type of diagenesis and its evolution are the key to determine the pore structure of reservoirs,and the tectonics is the way to improve reservoirs.The above research results have important guiding significance for the classification and evaluation of the H3 reservoir of Huagang Formation in the study area and the next step of natural gas exploration and development.