石油初次运移动力学模型研究及其应用

烃源岩中生成的油气经过初次运移, 进入到储集层, 其本质应该是一个动力学过程。前人对于油气初次运移动力学有一定的研究, 但是定量研究较少。本文以烃源岩中石油初次运移为研究对象, 建立下生、上储型排烃地质模型, 从微观动力学的角度对即将进入储集层的游离相石油进行力学分析, 认为烃源岩中的石油发生初次运移进入储集层是一个动力和阻力的力学非平衡过程, 运移动力包括烃源岩地层压力和烃源岩层毛细管力, 运移阻力包括储集层地层压力、储集层毛细管力和内摩擦力。当动力大于阻力时, 石油发生初次运移; 当动力与阻力相等时, 对应着石油初次运移的临界状态; 当动力小于阻力时, 石油不能发生初次运移。因此, 可以通过对比石油初次运移动力和阻力的大小定量地预测石油初次运移充注窗口。本文将建立的石油初次运移力学模型应用到安塞油田长6段油藏, 定量地预测了石油初次运移充注窗口, 为进一步的油气勘探提供依据。

Research on oil primary migration dynamic model and its application

Through primary migration, the hydrocarbons from source rock can enter the reservoir layer, which is adjacent to the source rock. It is a dynamic process. There were some researches about dynamics of primary migration, but most researches have not yet reached quantitative standards. This paper took petroleum primary migration in source rock as the research object, established the corresponding geological model, in which the reservoir layer is above on the source rock. From micro-mechanics perspective, this paper further analyzed the forces of the petroleum, which is free-phase and about to enter into the reservoir layer, and considered that it is a non-equilibrium process between the power and the resistance for the petroleum from the source rock, which is going to enter into the reservoir layer. The powers of primary migration include the fluid pressure and the capillary force in the source rock, and the resistances include the fluid pressure and the capillary force in the reservoir layer and the internal friction force between petroleum and the fluid attached to the surface of mineral particles. When the power is bigger than the resistance, the primary migration can be happened; When the power is equal to the resistance, it is the critical state of primary migration for petroleum; When the power is smaller than the resistance, the primary migration can't be happened. Therefore, by comparing the power and the resistance of primary migration, we can quantitatively predict the petroleum-filling windows. And this paper applied the mechanics model of primary migration to the reservoir layer in Chang 6 member, Ansai oil field, and quantitatively predicted the petroleum-filling window of primary migration, looking forward to providing the basis for further exploration.