渤海湾盆地辽东凹陷旅大29构造沙二段近源砂砾岩体优质储层形成机理

研究砂砾岩储层成岩演化及优质储层成因机理对中深层油气勘探意义重大。综合运用铸体薄片、扫描电镜、泥岩X衍射（黏土和全岩）、包裹体、常规测井、核磁共振测井和埋藏史等资料，系统研究了渤海湾盆地辽东凹陷旅大29构造沙二段砂砾岩体成岩演化、裂缝特征及作用、优质储层成因及控制因素等内容。结果表明：沙二段储层处于欠压实带、弱胶结、局部溶蚀增孔以及非构造缝的发育，是形成优质储层的成因；沙二段砂砾岩发育原生缝和成岩缝两类裂缝，原生缝提供了重要的储集空间，裂缝极大改善了储层的孔隙结构和物性；源-汇过程控制了原生缝形成，贫K⁺泥岩与砾石原生缝的组合促进了构造抬升过程中收缩缝的形成，而缺少Ca²⁺、Mg²⁺、Fe²⁺、Fe³⁺等离子的岩石组分使大面积胶结物难以出现，保留了孔缝的有效性。对储层孔隙演化进行了恢复，认为沙二段储层在演化为低孔储层后才成藏。

Generation of High Quality Near Source Glutenite Reservoir of 2nd Member of Shahejie Formation in Lüda-29 Structure,Liaodong Sag,Bohai Bay Basin

The research on diagenetic evolution and generation of high quality reservoir is of great significance to medium-deep oil & gas exploration. A comprehensive analysis on casting thin section, scanning electron microscope, mud X-ray diffraction (XRD) (clay and total rock), inclusion, conventional logging, nuclear magnetic resonance (NMR) logging and burial history was conducted to find out diagenetic evolution, fracture features and function, generation of high quality reservoir and controlling factors of glutenite in the study area. The results indicated that:1) The generation of high quality reservoir was mainly due to regional dissolution and non-structural fracture development with low compaction, weak cementation and enhanced porosity. 2) Protogenetic and diagenetic fractures are developed in glutenite reservoir. Protogenetic fractures are important storage space, and fractures can improve pore structure and properties of reservoir significantly. 3) The source-sink process controlled the formation of protogenetic fractures. The shrinkage fractures were generated during uplift, which was promoted by combination of mud without K⁺ and inner-gravel fracture. The rock components, which is lack of ion like Ca²⁺,Mg²⁺,Fe²⁺,Fe³⁺, reduced cement extent, retained porosity.As a result, it became a low-porosity reservoir earlier than accumulation.