剪切作用对自发乳化驱油提高采收率的影响

Effect of Shear Action on Enhanced Oil Recovery of Spontaneous Emulsification Flooding

史胜龙 王业飞 汪庐山 靳彦欣 王涛 李文正

SHI Shenglong WANG Yefei WANG Lushan JIN Yanxin WANG Tao LIWenzheng

为获得剪切作用对自发乳化体系提高采收率的影响规律，通过引入无量纲剪切速率和有效水油流度比两个参数研究了填砂管渗透率、化学驱驱替速率和剪切强度对自发乳化体系驱油效果的影响，分析了驱油机理。研究结果表明：当填砂管渗透率较高且化学驱驱替速率较低时，无量纲剪切速率较低，形成的乳滴粒径较大，依 靠乳滴在孔喉处聚并产生的贾敏效应降低有效水油流度比、提高波及系数和采收率；随着填砂管渗透率降低或化学驱驱替速率增加，无量纲剪切速率增加，乳滴粒径变小，不能有效封堵水流通道，而被驱替液携带流出地层，降低有效水油流度比能力减弱，驱油效果变差。自发乳化驱乳化-捕集作用提高采收率效果优于乳化-携带作用，应降低驱替过程中无量纲剪切速率以获得较高的采收率。图6 表1 参15

In order to investigate the effect of shear action on enhanced oil recovery of spontaneous emulsification system，the oil displacement efficiency of spontaneous emulsification system under different sandpack permeability，displacement rate of chemical flooding and shear strength was investigated through introducing two parameters including dimensionless shear rate and effective mobility ratio of water to oil. The results showed that when sandpack permeability was high and the displacement rate of chemical flooding was low，the dimensionless shear rate was low，the particle size of emulsion droplet formed was large. Droplets could coalesce in pore throat and generate strong Jamin effect，and the effective mobility ratio of water to oil reduced so as to increase the sweep efficiency and oil recovery. The dimensionless shear rate increased with decreasing sandpack permeability or increasing chemical flooding displacement rate，which led to a reduce in particle size of emulsion. Emulsion droplets were insufficient to plug water channel effectively and entrained out of formation with displacing fluid，due to limited capability of reducing the effective mobility ratio of water to oil result in lower oil displacement efficiency. Therefore，the effect of enhanced oil recovery of emulsification and entrapment effect of spontaneous emulsification flooding was better than that of emulsification and entrainment effect，and the oil recovery could be improved by reducing the dimensionless shear rate during flooding.

10.19346/j.cnki.1000-4092.2016.06.022