济阳坳陷古近系超高压成因探讨

分析了济阳坳陷古近系压力场分布特征,并用地化分析数据和地层压力及油气显示等相关资料分析了地层超压与含油气性的关系:济阳坳陷地层超压可分为"自源超压"和"它源超压"2种类型。烃源岩残留烃演化与地层自源超压演化具有较好的对应关系;几乎所有的超压储集层均具有一定的油气显示;深洼陷带油气藏剩余压力与油气充注程度总体上具有正相关关系。研究表明,济阳坳陷地层超压主要是来自于烃源岩的高压含烃流体注入储集层后形成异常高压。根据渗流理论分析、运移模拟实验和地层原油黏度变化特点,分析了液态烃生成的间接增压作用。

Approach to Paleogene Overpressure Origin in Jiyang Depression

The relationship between formation overpressure and petroliferous property was analyzed using the geochemical data and statistical information as well as the pressure field characteristic of the Paleogene in Jiyang depression.The overpressure in Jiyang depression can be divided into autochthonous overpressure and allochthonous overpressure.The evolvement of residual hydrocarbons in source rocks is well consistent with the evolvement of autochthonous overpressure in strata.All the reservoirs with overpressure are almost of oil-gas shows.The remained pressure of reservoir in deep sag zone has normal correlation with oil-gas charging degree.The study shows that the overpressure in Jiyang depression strata originates from incremental pressure of hydrocarbon generation,namely,abnormal high pressure formed following charging high pressure fluids with hydrocarbons into reservoirs.According to oil-water phase percolation theoretical analysis,oil migration physical model experiment and in-situ oil viscosity variation in Jiyang depression,the indirect pressurization mechanism for liquid hydrocarbon generation in source rocks was also analyzed.