鄂尔多斯盆地周家湾地区延长组长8储层特征及影响因素分析  

Analysis of influencing factors and characteristics of Chang8 reservoirs of Triassic Yanchang Formation in Zhoujiawan area, Ordos Basin

作　　者：王维斌[1] 高俊梅[1] 王永宏 马文忠 史立川 于雷 任瑞清 

机构地区：[1]中国石油长庆油田分公司勘探开发研究院,低渗透油气田勘探开发国家工程实验室

出　　处：《低渗透油气田》2015年第2期26-33,共8页

基　　金：国家重大基金项目“中国非常规油气储层分类与典型地质模型建立”（编号：41390451）.

摘　　要：根据大量铸体薄片、扫描电镜、高压压汞、常规物性、x衍射等岩心分析化验资料，对鄂尔多斯盆地周家湾地区长8砂岩储层岩石学、储集空间、孔隙结构、物性及成岩特征进行了详细研究。结果表明，该套储层具有低石英、高长石、高岩屑的岩石学特征，岩石类型以岩屑长石砂岩、长石岩屑砂岩为主，且填隙物含量较高。储层物性及孔隙结构总体较差．属于典型的低孔、超低渗透储层，储集空间以剩余原生粒问孔和次生长石溶孔为主，喉道以片状、弯片状喉道为特征。造就了长8储层中等排驱压力、高中值压力、小喉道半径、低退汞效率的特点。此外．储层孔隙度和渗透率具有很好的线性关系．说明储集和渗透能力主要依赖于砂岩基质的孔隙与喉道．微裂缝对改善储层孔隙和渗透性的贡献有限。研究发现，沉积成岩相共同控制了储层平面分布和发育程度．分流河道和水下分流河道砂体是最有利于储层发育的沉积微相．建设性成岩作用有效改造了储层物性，长石溶蚀相、残余粒间孔-长石溶蚀相是该区最为有利的成岩相带。According to a large number of core analysis data, such as cast thin section, scanning electron microscopy, high pressure mercury intrusion, routine physical properties, and X-ray diffraction, the authors studied in detail the petrology, reservoir space, pore structure, physical properties and diagenetic characteristics of the Chang8 sandstone reservoirs in the Zhoujiawan area of Ordos Basin. The results show that the reservoir has petrological characteristics of low quartz, high feldspar, and high cuttings contents, Its rock types are mainly lithic feldspathic sandstone, feldspathic lithic sandstone, with high interstitial content. Reservoir properties and pore structures are poor as a whole, being a typical low porosity, extralow permeability reservoir. The reservoir space is mainly remaining primary intergranular pores and secondary feldspar dissolved pores. The throats are characterized by flaky/sheet or bent-sheet throats. All of these cause the Chang8 reservoirs with characteristics of a medium expulsion pressure, high to middle pressure, small throat ra- dius, and low efficiency of invertive mercury. In addition, the reservoir porosity and permeability has a good linear relationship, indica- ting the reservoir and percolation ability depends mainly on the pores and throats of the sandstone matrix, The contribution of microfrac- tures to the improvement of reservoir porosity and permeability is very limited. The study found that sedimentary diagenetic facies jointly control the planar distribution and development degree of the reservoir. The distributm~ channels and underwater distributary channels＇ sand body are sedimentary microfacies as the most conducive to the development of reservoir. Constructive diagenesis effectively transforms the reservoir properties. Feldspar dissolution facies, residual intergranular pore-feldspar dissolution facies is the most favorable diagenetic facies in the area.

关 键 词：储层特征 成岩作用 影响因素 延长组 周家湾地区 鄂尔多斯盆地 

分 类 号：TE341[石油与天然气工程—油气田开发工程]