湖相混积岩碳酸盐组分成岩作用及其孔隙结构特征
——以新疆吉木萨尔凹陷二叠系芦草沟组为例

Diagenesis and pore structure characteristics of carbonate component of lacustrine mixed rocks: a case study of Permian Lucaogou Formation in Jimusar Sag，Xinjiang

张方 高阳 彭寿昌 高全慧 程乐利 印森林

中国石油新疆油田公司勘探开发研究院，新疆 克拉玛依 834000 中国石油西部钻探工程公司，新疆 克拉玛依 834000 长江大学录井技术与工程研究院，湖北 荆州 434023

Research Institute of Exploration and Development, Xinjiang Oilfield Company, PetroChina, Karamay 834000, China Xibu Drilling Engineering Company, PetroChina, Karamay 834000, China Institute of Mud Logging Technology and Engineering, Yangtze University, Jingzhou 434023, China

利用普通薄片、铸体薄片、X衍射、扫描电镜、高压压汞等测试分析资料，对研究区混积岩碳酸盐组分成岩作用、孔隙结构特征及其对渗透率的贡献等进行了研究。结果表明：在酸碱交替成岩环境中，碳酸盐组分成岩作用主要包括压溶作用、酸性溶蚀作用、白云石化与去白云化作用和重结晶作用等；芦草沟组混积岩储层目前处于中成岩阶段A2期；研究区碳酸盐岩类储层可分为泥晶白云岩和砂质/泥质泥晶白云岩，孔隙类型主要为溶蚀形成的粒间溶孔，长石颗粒发生溶蚀形成的粒内溶孔、晶间孔、微裂缝，以及少量的鲕粒间溶孔、生物格架内孔隙等类型，主要发育纳米级孔喉系统；2类碳酸盐岩类储层的主要渗流能力来源于0.01~0.20 μm的纳米级孔喉。

The diagenesis, pore structure characteristics and their contribution to permeability of the carbonate components of the mixed rock are studied by analyses of ordinary thin sections, casting thin sections, X-ray diffraction, scanning electron microscopy and high-pressure mercury injection. The results show that  in the acid-base alternate diagenetic environment, the diagenesis of the carbonate component mainly includes pressure dissolution, acid dissolution, dolomitization and dedolomitization and recrystallization, etc. The Lucaogou Formation mixed rock reservoir is currently in the A2 phase of the middle diagenesis stage; the carbonate reservoirs in the study area are mainly dolomicrite and sandy/muddy dolomicrite. The pore types are mainly intergranular dissolved pores formed by dissolution, intragranular dissolved pores formed by dissolution of feldspar particles, intercrystalline pores, micro-cracks, and a small amount of pores between the oolitic particles and orgainism framework pores, most of them are nanoscale pore-throat systems; the main percolation capacity of the two carbonate reservoirs comes from the nanoscale pore-throat between 0.01-0.20 μm.

10.6056/dkyqt202005005