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The Study On The Mechanism Of Generation-expulsion Of Terrestrial Source Rocks

Posted on:2007-06-30Degree:DoctorType:Dissertation
Country:ChinaCandidate:Y H LiaoFull Text:PDF
GTID:1100360185953193Subject:Institute of Geochemistry
Abstract/Summary:PDF Full Text Request
The dissertation entitled "The study on the mechanism of generation-expulsion of terrestrial source rocks" has been focusing on the following points: Can coal generate and expel some liquid oil? What are the characteristics of the oil generated by coals? Could expulsion and primary migration affect the compositions of oils from terrestrial source rocks? What factors can impose on the expulsion efficiency and fractionation of oil, and how these factors act? What factors can impose on the carbon isotopic fractionation during generation-expulsion process, to what extent and how they act? The following chapters will answer these questions one by one.Experimental simulation of generation and expulsion of six selected terrestrial source rock samples and the related numerical simulation were carried out in the research. In addition, the experimental simulation of primary migration for three samples among them was also carried out to study the carbon isotopic fractionation during primary migration of oil from source rocks. The following results were achieved:1) By generation-expulsion simulation experiment, the potentials of oil generation of the source rock samples (mainly coals) were evaluated and the influence of secondary crack was also evaluated. The expulsion efficiency and fractional effects during expulsion were evaluated, too.2) Numerical models (GCR) were established to simulate how terrestrial source rocks generate and expel out oil according to the characteristics of source rocks, such as maceral compositions, HI values, porosity, specific surface areas and the different generation behavior at every stage. The research also evaluated how the parameters of Qv and nano-porosity affect expulsion efficiency and fractionation.3) The total carbon isotopic fractionation effect during generation-expulsion process of different terrestrial source rocks was evaluated. It is also evaluated that to what extent the primary crack of different kerogens and secondary crack of hydrocarbons can affect the carbon isotopic fractionation during the generation-expulsion process. It is demonstrated that there are different fractionation effects in different source rocks. The distribution pattern of the carbon isotopic compositions of the individual n-alkanes shows almost no change during this process. All of these should be considered in oil-source correlations.4) The result of the primary migration simulation suggests that there are different carbon isotopic fractionation effects in the primary migration of different source rocks. Diffusion capacities of hydrocarbons in different source rocks are very different, which should be responsible for the carbon isotopic fractionation.
Keywords/Search Tags:terrestrial source rocks, hydrocarbon generation-expulsion, stable carbon isotopic fractionation, pyrolysis simulation, numerical simulation
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