原油组分极性影响砂岩油藏润湿性的分子模拟

Molecular simulation of the effect of crude oil component polarity on the wettability of the sandstone oil reservoirs

为了考察砂岩油藏中原油组分极性对矿物表面润湿性的影响,从微观分子角度出发,构建α-石英晶面模型,并选取了不同极性的原油组分与水分子组合构建成符合真实油藏的三相模型。运用分子动力学模拟方法中的相对浓度分布函数及表面能研究了原油组分对砂岩油藏润湿性的影响。结果表明,在成藏过程中,极性越强的原油组分其相对浓度分布峰值越接近石英表面,与石英表面的吸附能也越大,穿越水膜并吸附于矿物表面的能力越强,可在石油表面形成油膜实现润湿反转,该规律对砂岩油藏开发具有指导意义。

In order to investigate the influence of the polarity of the crude oil components on the surface wettability of minerals in sandstone reservoirs.From a microscopic molecular perspective,α-quartz crystal surface model is constructed,and different polarity crude oil components and water molecules are selected to form a three-phase model that conforms to the real oil reservoir.The effects of crude oil components on the wettability of sandstone reservoirs are studied by molecular dynamics simulation method through relative concentration distribution function and surface energy.The results show that in the process of accumulation,the crude oil component with stronger polarity has a peak relative concentration distribution close to the quartz surface,the adsorption energy with the quartz surface is also greater,and the ability to pass through the water film and adsorb on the mineral surface is stronger,which can be the formation of oil film on the oil surface to realize wetting reversal.This law has guiding significance for sandstone reservoirs development.