计算注水开发不同阶段体积波及系数的新方法

A new method for calculating volume sweep coefficient at different stages of water injection development

体积波及系数是油田评价开发效果、制定开发调整方案的重要依据。为了研究注水开发不同阶段体积波及系数的变化规律,从注入孔隙体积倍数角度出发,根据油水相对渗流理论与油藏工程原理,提出了驱油效率与注入孔隙体积倍数的计算模型,建立了体积波及系数计算方法,并以胜利油田3个试验区为例进行了计算与分析。结果表明:驱油效率与注入孔隙体积倍数之间满足指数方程,二者关系曲线呈上凸型;随着注入孔隙体积倍数的增大,驱油效率由最小驱油效率逐渐增大,并趋近于最大驱油效率;对驱油效率计算模型进行验证,预测值与实测值的平均相对误差仅为1.90%;水驱开发过程中体积波及系数与注入孔隙体积倍数关系曲线整体呈快升-缓升-近平台状演变趋势,计算结果能够指导开发调整措施的效果评价;3个试验区目前体积波及系数接近90%,波及区内存在大量剩余油,亟需开展波及区内主体剩余油的描述与启动方法研究。

The volume sweep coefficient is essential for evaluating the development effect and formulating development adjustment plans for oil fields.This paper aims to study the variation law of volume sweep coefficient in different stages of water injection de-velopment.From the perspective of the injection pore volume multiple,a calculation model is built of displacement efficiency and injection pore volume multiple,and a calculation method of volume sweep coefficient is proposed based on oil-water relative flow theory and reservoir engineering principle.In addition,three test areas of Shengli Oilfield are taken as examples for calculation and analysis.The results show that the relationship between the displacement efficiency and the injection pore volume multiple satisfies an exponential equation,and the relationship curve between the two is upward convex.As the injection pore volume multiple in-creases,the displacement efficiency gradually increases from the minimum displacement efficiency and approaches the maximum displacement efficiency.The displacement efficiency calculation model is verified,and the average relative error between the pre-dicted and measured values is only 1.90%.During the water flooding development,the relationship curve between the volume sweep coefficient and the injection pore volume multiple shows an evolution trend of fast rising,slow rising,and near platform.The calculation results can guide the effect evaluation of development adjustment measures.At present,the volume sweep coeffi-cient of the three test areas is about 90%.There is a large amount of remaining oil in the swept area.It is urgent to study the descrip-tion and start-up method of the main remaining oil in the swept area.