神府南区致密气储层有效性及主控因素  

Effective Characteristics and Main Controlling Factors of Tight Gas Reservoirs in Southern Shenfu area

作　　者：高玉飞 李鑫 周姗姗 王诗琪 Gao Yufei;Li Xin;Zhou Shanshan;Wang Shiqi(CNOOC Research Institute Ltd.,Beijing 100028,China)

机构地区：[1]中海油研究总院有限责任公司,北京100028

出　　处：《地球科学》2024年第12期4518-4529,共12页Earth Science

基　　金：国家自然科学基金(No.42202157);中国博士后科学基金(No.2021M693543)。

摘　　要：致密气储层非均质性强,有效储层预测难度大.以神府南区石炭系-二叠系为研究对象,通过薄片、孔渗、压汞、产能分析等方法,开展储层有效性研究和有效储层主控因素分析.结果表明:(1)储层以岩屑砂岩、长石岩屑砂岩为主,且物性呈现低孔低渗特征;(2)结合产能判定物性下限为7%孔隙度和0.1 mD渗透率,有效储层孔喉主要分布在750~3 900 nm,占比超过50%,对应于溶蚀孔隙,而致密储层孔喉<80 nm,占比超过80%,对应于黏土晶间孔隙;(3)水下分流河道有效性占比超过70%,是有效储层发育的高能相带;(4)储层孔隙类型为次生成因,占比超过85%,主要为晚成岩阶段有机酸溶蚀长石后形成的溶蚀孔隙.基于上述分析,高能微相和次生溶蚀的耦合作用是有效储层发育的主控因素.Tight gas reservoir heterogeneity is strong and the effective reservoir prediction is difficult.In this paper,the main gas-producing layers within Carboniferous-Permian Formation in the southern Shenfu area were taken as the research object.The effective characteristics and the main controlling factors of effective reservoirs were studied by means of thin section observation,physical property test,mercury injection experiment and productivity analysis.The results show that the reservoirs are mainly composed of lithic sandstone and feldspar lithic sandstone with low porosity and permeability.Combined with productivity,the lower limit of reservoir physical properties can be manifest as 7%porosity and 0.1 mD permeability.Mercury intrusion-fractal characterization shows that the effective reservoir pores are mainly distributed in the range of 750-3900 nm,accounting for more than 50%,corresponding to the dissolution pores.However,the tight reservoir pores are concentrated in the range of 0-80 nm,accounting for more than 80%,corresponding to the clay intercrystalline pores.The effectiveness of underwater distributary channel accounts for more than 70%,which is a high-energy facies belt for effective reservoir development,and can be proven by sorting and particle size analysis.The pore type is mainly the dissolution pore with secondary origin,accounting for more than 85%.Generally,the dissolution pore formed after the dissolution of feldspar by organic acids in the late diagenesis stage.The larger the amount of feldspar dissolution,the higher the porosity and permeability.Based on the above analysis,the coupling of high-energy microfacies and secondary dissolution is the main controlling factor of effective reservoir development.

关 键 词：致密气 有效储层 非均质性 主控因素 神府南区 石油地质 

分 类 号：P618[天文地球—矿床学]