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针对烃源岩生排烃效率评价现有方法的不足和第四次油气资源评价研究的需要,基于模拟地质条件的最新生排烃实验平台,以白垩系烃源岩为例,开展了松辽盆地烃源岩生排烃条件和过程的模拟实验。结合包括轻烃在内的产物计量方法探索,对实验产烃量进行计量;通过实验产物的H/C原子比数据,对干酪根热成熟度进行标定,获得实验点所对应的地质RO值;从而实现了对松辽盆地白垩系烃源岩在各热演化阶段的生排烃效率厘定。结果表明,轻烃在总烃中的含量为5%~29%,并有随实验热演化程度升高的特征,在生油高峰期的轻烃含量约为25%,从而弥补了传统实验和利用岩心残留烃分析排烃效率方法中缺少轻烃组分的缺憾;通过生排烃效率曲线显示,松辽盆地白垩系烃源岩的最大生油效率为680mg/gTOC,生油高峰期对应的绝对排烃效率为57%。对压力的影响分析认为,压力确实影响热成熟演化,在生油阶段对RO的抑制约为0.2%;压力的释放促进排烃,是导致岩心滞留烃量降低和轻烃散失的主要原因,仅轻烃散失造成的生油高峰期绝对排烃效率偏差值就达18%。常规方法低估了地质实际的滞留烃量,深层找气的前景乐观。
In view of the existing methods of evaluating hydrocarbon generation and expulsion efficiency of hydrocarbon source rocks and the need of the fourth hydrocarbon resource assessment study, based on the latest experimental platform for hydrocarbon generation and expulsion with simulated geological conditions and taking Cretaceous source rocks as an example, the Songliao Basin Simulating Experiment on Condition and Process of Hydrocarbon Generation and Discharge in Source Rock. Combining with the measurement of product including light hydrocarbon, the experimental hydrocarbon production was measured. The thermal maturity of kerogen was calibrated by H / C atomic ratio data of the experimental product to obtain the geological RO value corresponding to the experimental point. Thus, the hydrocarbon generation and expulsion efficiency of the Cretaceous source rocks in the Songliao Basin at various stages of thermal evolution are determined. The results show that the content of light hydrocarbons in the total hydrocarbons is 5% ~ 29%, and with the thermal evolution of the experimental characteristics of the increase in the peak of crude oil light hydrocarbon content of about 25%, thus making up for the traditional experimental and Using the residual hydrocarbon in core analysis, it is lack of light hydrocarbon component in the hydrocarbon expulsion efficiency method. According to the hydrocarbon generation and expulsion efficiency curve, the maximum oil production efficiency of Cretaceous source rock in Songliao Basin is 680mg / gTOC. Correspondingly, Absolute discharge efficiency of 57%. The analysis of the influence of pressure shows that the pressure does affect the evolution of thermal maturation, and the inhibition of RO during the oil production stage is about 0.2%. The release of pressure promotes the hydrocarbon expulsion, which is the main reason for the decrease of the amount of retained hydrocarbons and the loss of light hydrocarbons in the core. The loss of light hydrocarbons caused by absolute peak hydrocarbon output efficiency of the deviation of up to 18%. The conventional method underestimates the actual amount of retained hydrocarbons in the geology and optimizes the prospect of deep gas discovery.