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对鄂尔多斯盆地西缘侏罗系延安组低成熟页岩样品进行热模拟实验和岩石热解实验,分析岩石热成熟度(R_o)与生烃率及热解烃率(S_2)之间的变化规律,以及热解烃量与生烃量的关系。研究表明,陆相低成熟页岩气态烃产率随R_o的升高呈线性增加,液态烃产率随R_o的升高先增加后下降。产烃率随R_o的上升呈指数增加,热解烃率随R_o上升呈指数减少。热解烃率与产烃率之间具有良好的线性负相关,产烃率在热解烃率下降的过程中呈线性增加。陆相页岩生烃演化可分为3个阶段:游离烃释放及初期热降解的未成熟阶段、热降解-热裂解的成熟阶段和热裂解的过成熟阶段。根据生烃模拟中气态烃增长率和液态烃产率突增,以及第一个生烃高峰时所对应的R_o值,确定了鄂尔多斯盆地西缘侏罗系延安组陆相页岩油气有利区和目标区的关键参数R_o和TOC的下限。
Thermal simulations and rock pyrolysis experiments were conducted on the low-mature shale samples of the Jurassic Yan’an Formation in the western margin of the Ordos Basin to analyze the variation of thermal maturity (R_o), hydrocarbon generation rate and hydrocarbon dissociation rate (S_2) , And the relationship between the amount of pyrolysis hydrocarbons and the amount of hydrocarbon generation. The results show that the yield of gaseous hydrocarbons in low-mature continental shale increases linearly with the increase of R_o, and the yield of liquid hydrocarbons increases first and then decreases with the increase of R_o. The hydrocarbon yield increased exponentially with the increase of R_o, and the pyrolysis hydrocarbon rate decreased exponentially with the increase of R_o. There is a good linear negative correlation between the pyrolysis hydrocarbon yield and the hydrocarbon production rate, and the hydrocarbon production rate increases linearly during the pyrolysis hydrocarbon reduction. The evolution of continental shale hydrocarbon generation can be divided into three stages: the immature stage of free hydrocarbon release and initial thermal degradation, the thermal degradation - the mature stage of thermal cracking and the over-maturation stage of thermal cracking. According to the hydrocarbon hydrocarbon growth rate and the sharp increase of liquid hydrocarbon yield in the hydrocarbon generation simulation and the R_o value corresponding to the first hydrocarbon generation peak, the favorable area of continental shale hydrocarbon in the Jurassic Yan’an Formation in the western margin of Ordos Basin and The key parameters of the target area R_o and the lower limit of TOC.