渗透率非均质性对多层系统水驱效率的影响

摘要

Usually the diagenetic randomness of a reservoir results in the heterogeneous of the reservoir. The relative statistical data show that the permeability distributions of many types of oil reservoirs are accordant with those of log normal state, but the variation coefficient of the permeabilities is one of an important parameters to describe the heterogeneity of an oil reservoir. Field statistic method can be divided into the following two methods: statistical theory formula and Dykstra-Parsons empirical formula. Reservoir heterogeneity is mainly characterized by vertical displacement during the waterflooding development. Through the average weighting of the thickness in the physical properties of the system, the similar homogeneous Buckley-Leverett model is obtained. At the same time, the permeability variation coefficient and mobility ratio are introduced into the curves of waterflooding efficiency and water cut to reflect the influences of the heterogeneity and mobility ratio on the waterflooding performances in linear stratified system. The calculation results show that the greater the permeability variation coefficient and mobility ratio, the poorer the waterflooding effects of the system. At this time, the technological countermeasures such as water plugging, profile control and so on are needed for the system.%储层成岩作用的随机性导致储层通常表现出非均质性,有关统计资料表明很多类型油藏的渗透率分布均满足对数正态分布,而渗透率变异系数是描述油藏非均质性的一个重要参数,矿场统计方法分为统计学理论公式法、Dykstra-Parsons经验公式法.油藏的非均质性在注水开发中主要体现在纵向驱替上,通过对系统物性按厚度进行平均加权得到了近似的均质Buckley-Leverett模型,同时将渗透率变异系数、流度比引入到水驱驱替效率曲线及含水率曲线中,以此来反映非均质性和流度比对线性层状系统的水驱效率的影响.计算结果表明渗透率变异系数越大,流度比越大,层状系统的水驱效果越差,此时需要对系统讲行堵水调剖等工艺措施.