岩石孔喉道中表面粗糙度对油水两相流动的影响

The effects of the pore throat roughness on the water-oil flow in rock reservoirs

岩石孔喉道中表面粗糙性是影响油水两相流动的重要因素之一.本文利用格子波尔兹曼数值模拟方法模拟了在光滑和粗糙孔喉道中的水驱油的流动特性,通过比较亲水和亲油的孔喉道模型中的含水饱和度、油水相对渗透率的变化,分析粗糙度对于流动特性的影响.结果表示:1)无论是亲水性还是亲油性模型,孔喉道表面的粗糙性对于油水流动都起阻碍作用;2)由于孔喉道表面粗糙元间空隙的存在,一部分油被圈闭于空隙中,不能实现完全驱替;3)水驱油的过程中,亲水性的孔喉道的含水饱和度和油水相对渗透率均高于亲油性孔喉道;4)在亲水性孔喉道中,粗糙性对含水饱和度和油水相对渗透率的影响更为明显,亲油性孔喉道次之;5)亲油性孔喉道的粗糙性增加到一定的程度后,它对流动的阻碍作用不再随着粗糙性的增加而逐渐增强.

As one of the important factors to affect the oil-water flow, it is requisite to study the influence of the pore throat roughness on flow behaviors. In this paper the Lattice Boltzmann method is employed to model the water displacing oil in the flat and the rough pore throat models. The comparisons of the water saturation and water-oil relative permeability in different models show that： 1） both in the flat and the rough pore throat models, the roughness would retard the oil and water flow in the process of water displacing oil no matter the pore throat wall is water-wet or oil-wet; 2） some oil are trapped in the grooves between the rough elements and the maximal displacing efficiency is under 100M in the case of water displacing oil; 3）the displacing efficiency in the water-wet models is higher than that in the oil-wet pore throat models, and there are higher water saturation, water and oil relative permeability in the water-wet models; 4）the roughness has a more apparent effects in water-wet models than in the oil-wet models; 5）once the wall roughness reaches a level, it effects on flow behaviors are not increased with the growing roughness any more in the oil-wet pore throat models.