摘要
川东北地区二叠系大隆组泥岩的硅质成因复杂,基于乐坝1井岩心、薄片和地球化学等资料,开展了泥岩岩相划分,分析了不同类型岩相泥岩矿物组成、储集特征、含气性和硅质成因,结合岩石力学参数,分析了不同硅质成因泥岩的可压裂性差异,优选了甜点层段并分析了勘探潜力。研究结果表明:研究区大隆组泥岩可以划分为3种岩相:其中下部的富碳—中硅—中钙泥岩和中部的富碳—高硅—低钙泥岩分别具有较高—最高的TOC、孔隙度和含气量,有机质孔相对发育且孔隙类型以介孔—微孔为主;泥岩的硅质主要来源于生物作用,热液有一定影响;其具有相对较小的抗压强度和泊松比、较大的杨氏模量,可压性相对较好。上部的中低碳—高硅—低钙泥岩具有低TOC、低孔隙度、低含气量的特征,其有机质孔不发育,孔隙类型以介孔为主;硅质主要来源于火山热液作用;其具有相对较大的抗压强度和泊松比、较小的杨氏模量,可压性相对较差。总之下部的富碳—中硅—中钙泥岩和中部的富碳—高硅—低钙泥岩是地质工程“双甜点”层段,其展布稳定,保存条件好,埋深适中,是下一步有望实现勘探突破的有利层系。
The origin of siliceous from the Permian Dalong Formation mudstone in northeastern Sichuan Basin is complex. Based on the core, thin section, geochemical data and rock mechanics of Well Leba 1, the mineral composition, reservoir characteristics, gas-bearing properties, siliceous origin and fractibility of different lithofacies are analyzed. The research results show that the mudstone of the Dalong Formation in the study area can be divided into three types of lithofacies: The rich carbon-medium silicon-medium calcium of mudstone in the lower part and the rich carbon-high silicon-low calcium of mudstone in the middle have higher-highest TOC, porosity and gas content, respectively. Organic pores are relatively developed and the pore types are mainly mesopores and micropores. The siliceous of mudstone mainly comes from biological and hydrothermal fluid. It has relatively small compressive strength and Poisson’s ratio, large Young’s modulus, and relatively good compressibility.The middle-low carbon, high-silicon, low-calcium mudstone in the upper has lower TOC, porosity, and gas content, and its organic pores are not developed, the pore types are mainly mesopores;the siliceous mainly comes from volcanic hydrothermal action. It has relatively large compressive strength and Poisson’s ratio, small Young’s modulus, and relatively poor compressibility. In a word, the carbon-rich-middle silicon-middle calcium mudstone in the lower part and the carbon-rich-high silicon-low calcium mudstone in the middle part are the“double sweet spot” sections of geological engineering. They are stable in distribution, good in preservation condition and moderate in burial depth, which are favorable strata for further exploration breakthrough.
作者
李飞
刘珠江
陈斐然
魏富彬
郭金才
苏泽昕
LI Fei;LIU Zhujiang;CHEN Feiran;WEI Fubin;GUO Jincai;SU Zexin(SINOPEC Exploration Company,Chengdu 610041,China)
出处
《天然气地球科学》
CAS
CSCD
北大核心
2023年第2期349-358,共10页
Natural Gas Geoscience
基金
国家自然科学基金企业创新发展联合项目“海相深层页岩源—储动态演化与页岩气富集规律研究”(编号:U19B6003-03-03)资助.
关键词
川东北地区
大隆组
硅质成因
可压性
生物成因
Northeastern Sichuan Basin
Dalong Formation
Siliceous origin
Compressibility
Biogenesis
