苏里格气田东区山2段储层致密化主控因素定量分析

Quantitative evaluation of main controlling factors of reservoir densification of Shan-2 section in the east part of Sulige Gas Field

苏里格气田东区具有多层系含气特征,该区主力产层山2段受沉积、成岩综合影响,具有典型低孔—特低孔、特低渗—超低渗致密储层特征。综合应用岩石铸体薄片、扫描电镜、高压压汞、常规物性、X-射线衍射、流体包裹体测温、成岩演化序列重建、多元回归分析等技术手段与分析方法,对山2段的储层基本特征、成岩作用特征、成岩演化序列以及储层致密化主控因素进行了定性、定量分析。研究表明:储层沉积后经历了中—强压实、中等胶结、弱溶蚀等成岩改造,胶结作用、溶蚀作用与本区两期烃类充注密切相关;山2段目前处于中成岩B期末,储层致密化发生在中成岩B期中期;强压实、强硅质胶结与大量的软质岩屑、高岭石胶结主要导致了储层低孔—特低孔,储层特低渗—超低渗的三大核心因素则为伊利石、绿泥石、高岭石等黏土矿物胶结。研究结果对于深入认识山2段储层致密化进程,指导有利储层发育区预测具有重要意义。

The East part of Sulige Gas Field has many sets of gas-bearing strata. Influenced by sedimentation and diagenesis, the Shah-2 section sandstone reservoir possess the characteristic of low to ultra-low porosity, uhra-low to extra-low permeability. Qualitative/quantitative evaluation of the characteristic of reservoir, diagenesis, diagenetic evolution sequence and the main factors controlling sandstone densification were carried by casting slice, scanning electron microscope, high pressure mercury, physical proper- ties, X-ray diffraction, fluid inclusion analysis technique and reconstruction of diagenetic evolution sequence, multivariate regres- sion analysis method. The result show that after the sedimentation reservoir had experienced intense compaction, cementation and weak dissolution, diagenesis is closely related to the two stage hydrocarbon infill. The reservoir is currently in the later diagenetic B stage and the reservoir was completely compacted at the middle of middle diagenetic B stage. Among the numerous factors that can affect the quality of the reservoir, the intense compaction, cementation with soft rock debris and kaolinite lead to low to uhra-low po- rosity. The key factors related to low to ultra-low permeability are illite, chlorite, and kaolinite cementation. This research is important for recognizing the reservoir densification process of the Shan-2 Section, and predicting the favorable exploration areas.