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利用常规高压釜热压模拟仪和仿真地层热压生排烃模拟仪对南方海相不同类型烃源进行生烃模拟实验,研究发现不同类型原油烃气产率最高,分散可溶有机质烃气产率次之,产率最低的为不同类型干酪根。不同类型烃源烃气产率与烃源的有机碳含量、可溶有机质含量高低、有机质类型有密切关系,与烃源原始成熟度具有较好负相关性。烃源碳同位素组成决定产物甲烷碳同位素组成的演化规律,碳同位素组成较轻的烃源其产物甲烷碳同位素组成总体上要轻于碳同位素组成较重烃源的甲烷碳同位素组成。不同类型烃源产物甲烷碳同位素组成随热模拟温度增高具有先变轻再变重的演化特征,但不会重于其烃源的碳同位素组成。乙烷等碳同位素组成也随着热模拟温度增高逐渐变重,演化至生烃高峰时,碳同位素组成接近于其烃源碳同位素组成,可以示踪烃源。当演化至高过成熟阶段,乙烷等δ13C值大于其烃源碳同位素值,故不能仅用重烃碳同位素组成判断天然气母质类型。不同类型干酪根与可溶有机质CO2组分和同位素组成演化规律具有明显区别,可溶有机质生成的CO2和甲烷之间同位素分馏程度要比不同类型干酪根的大。在不同类型烃源生烃过程中,干酪根和液态烃碳同位素组成主要受母质类型控制,继承效应强,同位素分馏程度较小,具有很好的示踪意义,可以用于油源对比和烃源示踪研究。
Using conventional autoclave hot-pressing simulator and simulation stratum thermal-pressure hydrocarbon generation and expulsion simulator to simulate the hydrocarbon generation of different types of marine sources in the southern China, it is found that the hydrocarbon gas production rate of the different types of crude oil is the highest, and that of the dispersed and soluble organic hydrocarbon gas-producing Followed by the lowest yield for different types of kerogen. The hydrocarbon gas yields of different types of hydrocarbon sources are closely related to the organic carbon content, organic matter content, organic matter type of hydrocarbon source, and negative correlation with hydrocarbon source maturity. The carbon isotope composition of hydrocarbon source determines the evolvement rule of methane carbon isotope composition. The carbon isotope composition of methane with lighter carbon isotope composition is generally lighter than the carbon isotope composition of carbon source with heavier carbon isotope composition. The carbon isotope composition of methane from different types of hydrocarbon source products has the characteristics of light and heavy first, but not heavier than the carbon isotope composition of hydrocarbon source. Ethane and other carbon isotope compositions also become heavier as the thermal simulation temperature increases. At the peak of hydrocarbon generation, the carbon isotopic composition is close to that of its source carbon isotope, which can trace the hydrocarbon source. When the δ13C value of ethane and other δ13C values are higher than their hydrocarbon carbon isotope values at the stage of evolution to over high maturity, natural gas parent type can not be judged solely by the composition of heavy hydrocarbon carbon isotopes. Different types of kerogen and dissolved organic matter CO2 composition and isotopic composition of the evolution of a clear distinction between dissolved organic matter generated CO2 and methane isotope fractionation between different types of kerogen larger. In the process of hydrocarbon generation from different types of hydrocarbon sources, the carbon isotope composition of kerogen and liquid hydrocarbon is mainly controlled by the type of parent material, with strong inheritance effect and small degree of isotopic fractionation, which has good tracer significance and can be used for oil source contrast and hydrocarbon Source Tracing Study.