石油实验地质2025，Vol.47Issue(4)：767-780,14.DOI:10.11781/sysydz2025040767
四川盆地中部天府气区侏罗系沙溪庙组致密砂岩气储层岩石相类型与演化特征
Petrofacies types and evolution characteristics of tight sandstone gas reservoirs of Jurassic Shaximiao Formation,Tianfu gas area,central Sichuan Basin
摘要
Abstract
The classification of rock types is important for characterizing the heterogeneity of tight sandstone reser-voirs and revealing their differential evolution process.The Middle Jurassic Shaximiao Formation in the Tianfu gas area of the central Sichuan Basin was selected as the study object,and petrofacies types and diagenetic evolution process were investigated using thin-section observation,scanning electron microscopy(SEM),and stable carbon and oxygen isotope analysis.The gas-bearing reservoirs of the Shaximiao Formation in the Tianfu gas area exhibit strong heterogeneity in physical properties,pore types and distribution.Based on the differences in petrographic composition and texture,diagenetic patterns and processes,and pore structure characteristics,four types of petrofacies were classified:ductile-lean sandstone,ductile-rich sandstone,tightly calcite-cemented sandstone,and tightly laumontite-cemented sandstone.During the reservoir evolution process,ductile-lean sand-stone experienced moderate compaction,active fluid-rock interactions,and strong dissolution,and generally underwent multiple stages of dissolution and cementation,resulting in effective reservoir petrofacies.Ductile-rich sandstone underwent strong mechanical compaction,became dense in the early diagenetic stage,and exhibited weak fluid activity and slight dissolution in the late stage.In tightly calcite-and laumontite-cemented sandstone,calcite and laumontite were interlocked,resulting in early-stage densification and late-stage weak fluid modifica-tion.The original composition and texture of sediments controlled the differences in the influencing patterns and degrees of diagenesis within reservoirs.The concept of petrofacies provides a systematic framework for identifying key petrographic parameters that influence reservoir porosity and permeability.In combination with well logging data,this approach can effectively guide reservoir property modeling.关键词
致密砂岩气/岩石相/差异性成岩演化/沙溪庙组/四川盆地Key words
tight sandstone gas/petrofacies/differential diagenetic evolution/Shaximiao Formation/Sichuan Basin分类
能源科技引用本文复制引用
关旭,曹斌风,庞小婷,冉崎,杨长城,王小娟,朱德宇,潘珂,李飞,肖柏夷..四川盆地中部天府气区侏罗系沙溪庙组致密砂岩气储层岩石相类型与演化特征[J].石油实验地质,2025,47(4):767-780,14.基金项目
中国石油西南油气田公司重大科技专项"四川盆地中西部地区致密气勘探开发理论及关键技术研究"(2022ZD01)资助. （2022ZD01）
