一种水驱油藏波及系数解析计算方法

A new calculation method of water sweep efficiency in water drive reservoir

水驱油藏波及系数是油藏开发过程中的重要参数,目前实验、数模等求取方法存在操作繁琐、精度低、实用性差等问题,基于水驱特征曲线建立的油藏工程计算方法虽简便但在理论推导过程中对驱油效率和含水饱和度概念认识不清楚,使得推导结果不严谨。因此,有必要建立一种简便准确的解析求解方法。基于分流量方程和威尔杰方程,通过理论推导建立了一种基于油水相对渗透率曲线的水驱波及系数解析计算方法,可根据生产数据计算不同开发阶段的水驱波及系数。X油田计算表明,对于边水能量充足的南海海相稀油砂岩油田,开发初期原油主要来自于水驱波及范围的扩大,开发中后期原油主要来自于水驱波及范围内驱油效率的提高,该类油田开发技术政策初期应以完善井网,扩大水驱波及范围为主,中后期以换大泵提液,提高水驱洗油效率为主。本文建立的方法具有数据基础简单、计算简便快捷等优点,可广泛应用于油田动态分析和开发效果评价。

The water sweep efficiency is important parameters in oilfield development,but there are many problems in the calculation method,such as complicated operation,low precision and poor practicability,the calculation method of water sweep efficiency based on the water drive curve is not clear about the concept of the oil displacement efficiency and the water saturation,which makes the result of the derivation not rigorous.So it is necessary to establish a simple and accurate analytical solution method.Based on fractional flow equation and welge equation,a calculation method of water sweep efficiency based on relative permeability curve is proposed,which can be used to calculate water sweep efficiency in different oilfield development stages based on production data.The X oilfield calculation shows that for the south china sea marine sandstone oil field with abundant side water,the oil production is mainly from the water flooding region expansion in the initial oilfield developed period and then change to enhance oil displacement efficiency as the water sweep efficiency is to be stable,so the development policy of this oilfield should be to perfect production patterns nets in the initial oilfield developed period,then be to installe larger pumps and increase liquid production in the middle-later developed period.The proposed method is featured with accessible date,convenient calculation,showing a broad application prospect in dynamic analysis and development effect evaluation of oilfield.