天然气工业2025，Vol.45Issue(5)：1-16,16.DOI:10.3787/j.issn.1000-0976.2025.05.001
多期次构造运动背景下深层页岩天然裂缝发育特征及其油气地质意义
摘要
Abstract
Recently,Wells ZY2 and Z201 in the Ziyang Area of the Sichuan Basin have achieved significant oil and gas breakthroughs in the Cambrian Qiongzhusi Formation shale,which demonstrates the promising prospects of shale gas exploration and development in this formation.The development characteristics of natural fractures play a crucial role in the preservation,enrichment and effective exploitation of shale gas.To elucidate the development characteristics and controlling factors of natural fractures in the Cambrian Qiongzhusi Formation shale in the context of multiphase structures,this paper clarifies the types,characteristics,development patterns,and controlling factors of fractures by means of of field outcrop investigation,core observation,well log interpretation,high-resolution core scanning,UAV quantitative assistance and other techniques.In addition,the controlling effect of fractures on the enrichment,preservation and development of shale gas is discussed.And the following research results are obtained.First,the fractures developed in the Qiongzhusi Formation shale in this area are mainly tectogenetic shear fractures and tensile fractures,and the fractures of multip1e stages and types intersect to form a complex pore-fracture network.Fracture density varies greatly along the vertical direction,with the 1st,3rd,and 5th sublayers of the 1st Member of Qiongzhusi Formation exhibiting greater fracture density.There are four fracture patterns,i.e.,intralayer constrained type through-layer transitional type intralayer extensional type,and composite type,among which,the through-layer transitional type is widely developed.Second,the development of natural fractures is under the joint control of tectonic factors(fold and fault)and non-tectonic factors(TOC,brittle mineral content,lithology & lithofacies,and rock mechanical layer thickness).Fracture density exhibitsa negative exponential relationship with the distance from faults,that is,the farther from the fault,the lower and more stable the fracture density.The fracture density at the anticline core is significantly higher than at the flank.High TOC(≥2％)and high brittle mineral content(≥ 70％)are favorable for fracture development in shale.Fractures are developed in thin shale,and especially those in thin siliceous shale are the most developed.Third,natural fractures in the Qiongzhusi Formation shale have a significant influence on the stimulation effect of shale gas reservoirs by controlling the extension distance of hydraulic fractures and the complexity of fracture network.It is predicted that the overall recovery factor of shale gas can reach 35％by employing a development model of multi-layer tridimensional well pattern.In conclusion,the accurate characterization of natural fractures in the deep Qiongzhusi Formation shale in the context of multiphase tectonic movement is the key geological foundation for the effective development of deep shale gas under this structural background.The research findings provide critical geological evidence for optimizing the exploration and development strategies of this type of deep shale gas in this field.关键词
四川盆地/资阳地区/筇竹寺组/天然裂缝/发育特征/控制因素/多期次构造作用/页岩气富集Key words
Sichuan Basin/Ziyang Area/Qiongzhusi Formation/Natural fracture/Development characteristics/Controlling factor/Multiphase tectonism/Shale gas enrichment分类
能源科技引用本文复制引用
雍锐,田鹤,吴建发,刘勇,赵圣贤,刘文平,张德良,沈骋,谢圣阳,李博..多期次构造运动背景下深层页岩天然裂缝发育特征及其油气地质意义[J].天然气工业,2025,45(5):1-16,16.基金项目
中国石油天然气股份有限公司科技专项项目"页岩气规模增储上产与勘探开发技术研究"(编号:2023ZZ21). （编号:2023ZZ21）
