油滴在界面张力下的渗流——添加表面活性剂蒸汽吞吐微观渗流机理

Infiltration of oil droplets under interfacial tension:Microscopic flow mechanism of steam stimulation by adding surfactants

蒸汽吞吐开采稠油或超稠油经常添加水溶性表面活性剂。由于表面活性剂的影响,使得连续相的液体在毛细管中的渗透变成了油滴和水滴在多孔介质中的渗流,同时,由于渗流影响,表面活性剂在气泡或液滴上的分布是不均匀的,在气泡或液滴表面存在张力梯度。研究了油滴在毛细管中的渗流特征以及界面张力的变化对油滴渗流的影响,结果表明,原油的分散程度越好,油滴的尺寸越小,油滴的渗流速度将越快。在添加表面活性剂进行蒸汽吞吐开采时,油滴的渗流速度将提高,对提高采油速率十分有利。辽河油田杜80块兴隆台14口井、杜84块绕阳河东43口井、曙175块77口井试验表明:在1年的试验期内,3个区块累计增产油4.353×104t,油汽比分别提高0.336、0.403、0.001,增产效果明显。

Water soluble surfactants are added for heavy oil or super-heavy oil recovery by cyclic steam stimulation.Due to the effect of surfactants,the infiltration of liquid in continuous phase in capillaries becomes the flow of oil droplets and water droplets in porous media.At the same time,due to the effect of flow in porous media,the distribution of surfactants on bubbles or droplets is nonuniform,and so a tension gradient exists on the surfaces of bubbles or droplets.The study on infiltration characteristics and the effect of surface tension change on the movement of droplets reveals that the more dispersed the crude oil and the smaller the oil droplet size,the higher the oil droplet flow velocity.Adding surfactants in steam stimulation can increase the infiltration speed of oil droplets,favorable for enhancing oil production rate.According to a one-year field test on 134 wells（14 wells in Xinglongtai of Block Du-80,43 wells in east of Raoyanghe of Block Du-84,and 77 wells of Block Shu-175） in Liaohe Oilfield,the cumulative increase in production is 4.353×104 t,and the increases in GOR are 0.336,0.403 and 0.001,respectively,and the increases in production are significant.