应用生烃动力学方法研究库车坳陷烃源岩生烃史

The study on hydrocarbon generation histories in Kuqa depression using the method of kinetics

根据烃源岩生烃动力学参数,结合沉积埋藏史和古热史资料,本文应用生烃动力学方法研究了塔里木盆地库车坳陷三叠-侏罗纪烃源岩生烃史。研究表明,无论是煤,还是泥岩,库车坳陷三叠-侏罗纪烃源岩生气时间发生得晚,主生气期出现在10 Ma以来的喜山期晚期,生气高峰期出现在5 Ma之后。中上三叠世烃源岩生气时间和主生气期均早于中下侏罗世烃源岩。烃源岩这种晚期生气特征,为库车坳陷天然气的晚期聚集成藏提供了非常有利的烃源条件。

On the basis of the kinetic parameters of source rocks, with the combination of the data of sedimentary burial and paleothermal histories, hydrocarbon generation histories of Triassic-Jurassic source rocks in Kuqa Depression, Tarim Basin were studied using the method of kinetics in this paper. It demonstrated that Triassic-Jurassic source rocks （ e.g. coal and mudstone） in Kuqa Depression generated gas relatively later, which mainly occurred at the late stage of Himalayan Period （after 10 Ma） and main gas peak was in the last 5 Ma. The gas generation time and main gas peak of the Middle and Upper Triassic source rocks were slightly earlier than those of the Middle and lower Jurassic coal-bearing source rocks. The characteristics of late gas generation would provide the favorable hydrocarbon source for the late accumulation of natural gas in Kuqa Depression.