天然气工业2025，Vol.45Issue(5)：57-68,12.DOI:10.3787/j.issn.1000-0976.2025.05.005
海相页岩成烃演化与保存能力动态评价方法及有利区总有机碳含量下限探讨
Dynamic evaluation method of hydrocarbon generation evolution and preservation capacity of marine shale and discussion on TOC lower limit in favorable zones
摘要
Abstract
Marine shale in China is characterized by old sedimentary age,high degree of thermal evolution and complex preservation conditions.The original method of evaluating resource potential of shale gas neglets the dynamic process of shale gas generation and evolution,so it fails to reflect the real shale gas generation capacity effectively.Based on the sedimentation,burial and thermal evolution histories of the Upper Ordovician Wufeng Formation-Lower Silurian Longmaxi Formation highly evolved marine shale in Well JY2 of the Sichuan Basin,this paper proposes a dynamic evaluation method of the generation and preservation capacity of highly evolved marine shale gas.In addition,the shale gas generation capacity controlled by oil expulsion efficiency is studied by means of thermal simulation experiments.And from the perspective of shale gas generation,expulsion and retention,the whole process of shale gas generation and preservation is(semi-)quantitatively evaluated by combining forward and inverse modeling methods.On this basis,the TOC lower limit in favorable zones of shale gas is discussed.The following results are obtained.First,the forward thermal simulation experiments can show the contribution of kerogen and retained oil to the generation of shale gas,and can be used to establish the shale gas generation potential chart at different oil expulsion efficiencies.Second,the thermal stimulation experiments show that the largest oil expulsion efficiency of Wufeng-Longmaxi Formation in the oil generation stage is 68.79％,which is close to the average oil expulsion efficiency(66.52％)of Well JY2 inverted from solid bitumen.Third,the preservation ratio of highly evolved marine shale gas in Well JY2 of the Sichuan Basin is 10％-40％,which means 60％-90％of shale gas is lost in general.Fourth,TOC content has a certain controlling effect on the preservation of shale gas.The natural gas lost from the shale with residual TOC greater than 1.5％accounts for 60％to 80％,and that from the shale with residual TOC less than 1.5％accounts for 70％to 90％.Fifth,when the shale gas loss rate is 70％and the oil expulsion efficiency ranges between 50％and 80％,the TOC lower limit of shale in favorable zones is 1.77％-3.00％(Ro=2.0％)and 0.95％-1.70％(Ro=3.0％),respectively.In conclusion,the evaluation of highly evolved marine shale gas should not only focus on the loss of shale gas in the late reworking stage,but also on the oil expulsion in the early stage.The TOC evaluation index of favorable zones of shale gas should be determined from the perspective of its dynamic evolution.关键词
四川盆地/上奥陶统五峰组—下志留统龙马溪组/海相高演化页岩气/模拟实验/排油效率/TOC下限Key words
Sichuan Basin/Upper Ordovician Wufeng Formation-Lower Silurian Longmaxi Formation/Highly evolved marine shale gas/Simulation experiment/Oil expulsion efficiency/TOC lower limit分类
能源科技引用本文复制引用
马中良,崔海骕,宋振响,王远,何川..海相页岩成烃演化与保存能力动态评价方法及有利区总有机碳含量下限探讨[J].天然气工业,2025,45(5):57-68,12.基金项目
国家自然科学基金项目"三大盆地深层—超深层海相油气高效勘探开发基础研究"(编号:U24B6001)、中国石化科技攻关重大项目"中国石化'十四五'资评评价方法与数据库建设"(编号:P23229)、中国石化基础前瞻性研究项目"深层古老烃源岩生排滞油气机制与有效性评价"(编号:P24206). （编号:U24B6001）
