烃源岩生排烃理论研究与泥页岩油气

泥页岩油气的研究与勘探,必然涉及到烃源岩生排烃理论.但目前的干酪根热降解晚期生烃学说,是在油页岩热解生成页岩油概念基础上的提升,其理论明显脱离石油地质演化过程的实际,以该学说为指导研制的盆地模拟方法计算的油气资源量,表示的是烃源岩总有机碳全部热解生成石油的总量,即所谓的生油(烃)潜量,不是实际的生油量.通常含油气盆地都经历了持续沉降、整体上升、全面萎缩三个明显不同的发育阶段,盆地每个发展阶段都与成烃成藏过程有密切的关联,因此成盆成烃成藏是一个相辅相成、统一的石油地质演化过程.在持续沉降阶段,主要烃源岩基本上实现了成烃过程；整体上升阶段是盆地油气成藏的重要时期,并导致油气运移；全面萎缩阶段继续成烃完善成藏,不仅使整体上升阶段形成的油气藏继续充注油气,而且形成新的油气藏.干酪根热降解生成的石油受烃源岩(泥质岩)的孔隙空间限制,即烃源岩生油是在有限空间中进行的.通过确定烃源岩孔隙体积及其含油度等可定量计算烃源岩的生油量；通过盆地整体上升前后的烃源岩孔隙体积的变小量等可定量计算烃源岩的排油量.利用自行研制的DK-Ⅱ型地层孔隙热压生排烃模拟实验仪,开展了盆地持续沉降阶段烃源岩有限空间生烃模拟实验研究.要了解泥页岩油气的特征,必须从盆地的演化阶段及其与成烃成藏的密切关联入手.

Theory Study of Hydrocarbon Generation and Expulsion of Source Rocks and Oil and Gas in Shale

Research and exploration of the oil and gas in the shale must be related to the theory of hydrocarbon generation and expulsion of source rocks.But the present theory of later hydrocarbon generation by thermal degradation of kerogen is the advance of the concept of oil shale pyrolysis into shale oil,which is far away from the actual of evolutionary process of oil geology.Basin analog method guided by this theory is applied to the calculation of hydrocarbon resource.The quality is gross weight of petroleum generated by complete pyrolysis of total organic carbon in the source rocks,that is so-called potential oil(hydrocarbon)-generating volume not the actual oil-generating volume.In general,there are three obvious development stages in the petroliferous basins: continuance subside,entire ascension and comprehensive suppression,and every stage has close relationship with hydrocarbon generation and accumulation process.So hydrocarbon generation and accumulation of the basin is a unified evolutionary process of oil geology.At the stage of continuance subside,main source rocks generated into hydrocarbon basically;the stage of entire ascension is the important one of hydrocarbon accumulation of the basin and resulted in hydrocarbon migration;at the stage of comprehensive suppression,hydrocarbon generation and accumulation is continue and new oil-gas reservoirs are formed.The oil generated by kerogen thermal degradation is controlled by pore space of the source rocks(shale),that is to say,the space of hydrocarbon generation is limited.The fixed pore volume and oil-bearing degree of the source rocks may be used for quantitative calculation of oil-generating volume of the source rocks.Decrease of the pore volume of the source rocks before and after entire ascension stage of the basin may be used for quantitative calculation of oil-expulsion volume.Self-developed DK-Ⅱhydrocarbon-generation and expulsion simulated experimental apparatus through pore thermocompression is applied to the research of hydrocarbon-generation analog experiment in the limited space of the source rocks at the stage of the continuance subside.In order to know the feature of the oil and gas in shale,evolution stage of the basin and its close relationship between hydrocarbon generation and accumulation should be researched.