断陷盆地中油气运移研究方法的探讨

METHODOLOGY FOR THE RESEARCHES ON OIL/GAS MIGRATION IN FAULTDOWN BASINS

李明诚

Li Mingcheng

中国地质大学 北京

China University of Geosciences Beijing

油气的生成、运移、聚集受控于断陷盆地的演化和断裂活动.构造演化的旋回与异常流体压力的旋回往往具有一致性,生油岩成熟后断裂活动既能作运移的通道、又可形成圈闭;用动态分析法解释压实曲线能较可靠地获得有效生油层和排烃深度的信息;用地化资料追索运移路线和计算排烃率时要注意到干扰因素太多.应把以上三方面资料综合应用、互相验证,用“时序”的观点加以分析,才能在油气运移的研究中获得比较信服的结果.

Generally speaking,the generation and migration of oil and gas are essentially controlled by the evolution of a basin and faultings.The tectonic evolutionary cycles of a basin tend to be consistent with those of abnormal pressure of fluids.The period of faulting is most likely to be the main stage of oil/gas migration as the hydrocarbons become mature.The juxtaposition of sandstones and mudstones is resulted by faulting at both sides of a fault.Thereafter,oil/gas could migrate across or along the fault plane,i.e."stair-step" migration pattern.Such a migration pattern indicates that a fault plane can act not only as a migration path,but also as a trap.The data of the effective beds and the depth for hydrocarbon expulsion can be obtained by the interpretation of compact curves using dynamic analysis.Caution shoud be taken on applying geochemical data for oil/source rock correlation,tracing the migration path and calculating the expulsion rate of hydrocarbons because geochemical analysis would be interfered by many factors.The traditonal evaluation of source rocks based on the amount of residual hydrocarbons is not reliable enough.With the concept of "time sequence",the convinced results of the researches on oil/gas migration can be achieved only by the integrated analysis on the various data and informations mentioned above,which would checked by each other.

https://doi.org/10.11781/sysydz198802095