李家城则区长6致密砂岩成岩作用与影响因素

Diagenesis and influencing factors of Chang 6 tight sandstone in Lijiachengze area

崔维兰 张涛 张锦锋 冯坤茂 白玉彬3

延长油田股份有限公司靖边采油厂，陕西 榆林 718500 中国石化中原油田分公司勘探开发研究院，河南 濮阳 457001 西安石油大学地球科学与工程学院，陕西 西安 710065

Jingbian Oil Production Plant, Yanchang Oilfield Company Ltd., Yulin 718500, China Exploration and Development Research Institute, Zhongyuan Oilfield Company, SINOPEC, Puyang 457001, China School of Earth Sciences and Engineering, Xi′an Shiyou University, Xi′an 710065, China

综合应用铸体薄片、扫描电镜、荧光薄片、阴极发光及黏土矿物X衍射等技术，研究了靖边油田李家城则区长6致密砂岩成岩作用及影响因素。结果表明：长6储层胶结物成分主要为方解石、绿泥石和浊沸石；孔隙类型以残余粒间孔和各种溶蚀孔隙为主，平均孔隙直径为40～100 μm。影响储层物性的因素主要与沉积相和成岩作用有关，不同沉积相带储层物性具有显著的差异，尤以水下分流河道微相储层物性最好。压实作用是破坏储层物性的第一要素，其孔隙减小率平均为56.3%；胶结作用使储层进一步致密化，其平均孔隙减小率为30.０%；溶蚀作用一定程度改善了储层物性，其平均增孔率约7.3%；宏观及微观裂缝对储层渗透率有显著影响，而对孔隙度影响微弱。

The diagenesis and influencing factors of Chang 6 tight sandstone in Lijiachengze area of Jingbian Oilfield were studied by means of casting, fluorescence, scanning electron microscopy, cathodoluminescence, and X-ray diffraction of clay minerals. The results show that the cements in Chang 6 reservoir are mainly composed of calcite, chlorite and laumontite, and the pore types are mainly residual intergranular pores and various dissolution pores, with an average pore diameter of 40￣100 μm. The factors affecting reservoir physical properties are mainly related to sedimentary facies and diagenesis. The physical properties of reservoirs with different sedimentary microfacies and grain size change are obviously different, and the underwater distributary channel microfacies reservoirs have the best physical properties. Compaction is the first factor to destroy reservoir physical properties, with an average porosity reduction rate of 56.3%. Cementation further densifies the reservoir, with an average porosity reduction rate of 30.0%. Dissolution improves reservoir physical properties to a certain extent, with an average porosity increase rate of 7.3%. Macro and micro fractures have a significant impact on reservoir permeability, but have a weak impact on porosity.

10.6056/dkyqt201903007