Abstract: This paper deals with the primary migration occurring in a strata system in which a source rock is sandwiched between two carrier beds.The various geological conditions are taken into account to model pressuring process and pressure distribution in such a system.Based on the knowledge about petroleum primary migration,the phase of hydrocarbons is assumed as free phase,and pathways as pore/gorge,micro-fractures and Kerogen frame within the source rock.A numerical basin model is used to analyze the evolution of pressures and corresponding porosity.As a result of modelling,existence of higher excess pressures in source rocks and/or the sudden decrease of overpressures in neighbor permeable carriers may offer favorable migrating conditions.After discussed influences of geological and dynamic conditions affecting on migration process, the hydrodynamic analysis may be regarded as one of the most effective methods to study primary migration processes happening geo-historically in basin scale.

Key words: primary migration, migration forces, pressure distribution, dynamic method

摘要： 利用数值盆地模型模拟分析在砂岩-烃源岩-砂岩所构成的油气初次运移系统内流体压力的分布形式和演化特征,讨论油气以游离相态通过烃源岩的孔隙喉道、微裂隙和干酪根网络等通道形式发生初次运移的动力学条件。模拟结果表明,烃源岩保持较高的过剩压力或相邻砂岩发生高压释放的地质过程有利于油气初次运移的发生。相关的地质条件与动力学背景的定量分析应是在宏观上研究油气初次运移的有效途径。

关键词: 初次运移, 运移动力, 压力分布, 动力学方法