【作者】 罗万静；

【导师】 樊太亮； 王晓冬；

【作者基本信息】 中国地质大学（北京） ， 油气田开发工程， 2009， 博士

【摘要】 一个油田从发现到衰竭,是一个动态的、发展的和变化的过程,产量往往要经历上产、稳产、递减、调整上产、稳产、递减直至衰竭等多个开发阶段。而井网的早期合理布置与中后期的优化调整将是影响最终采收率的一个重要的因素。水平井的广泛应用、压裂技术的逐渐成熟以及低渗透油藏开发力度的逐渐加大,使得传统的经典井网产能预测方法已经不能适应复杂地质条件、各种新型的井网组合下的产能预测要求。推出一套考虑低渗透启动压力梯度、水平井注水和油水井压裂的产能预测方法对于指导生产具有重要的现实意义。论文系统回顾了国内外井网研究的发展和现状。对常用的井网产能评价方法:无穷井排压力叠加法、保角变换法、等值渗流阻力法、劈分流场法的优缺点进行了评价,指出了其适用条件。从直井-直井注采井网中五点、反七点、反九点井网产能入手,提出了一种采用镜像反演法、压力叠加法,将无穷井排的稳定渗流问题转化成为封闭体中的一口注水井或者采油井的拟稳态渗流问题,通过求取封闭边界中的油井、注水井的拟稳态压力方程得到无穷井排的井网产能公式的新方法。该方法与Muskat等经典公式得到的结果非常吻合。其中,五点井网、反七点井网、反九点井网与经典公式产能的相对误差为0、1%和3.91%。论文建立了三维拟稳态水平井渗流模型。采用压降叠加原理和高斯消元法得到分段射孔水平井的拟稳态产能公式。通过与直井产能对比得到拟稳态条件下的水平井当量井径。在直井-直井井网产能构建理念的指导下,求取了水平井-直井混合井网下的产能公式。该方法与目前采用其他方法计算结果的相对误差在1-7%以内,能满足工程精度要求。论文建立了考虑启动压力梯度的低渗透油藏直井-直井井网、水平井-直井井网产能公式,并针对油水井分别压裂或者整体压裂下的产能提出了评价方法。该方法有效的解决了低渗透油藏产能评价和见水时间预测。用拟稳态方法解决稳态渗流问题的思路将单井渗流问题和井网渗流问题统一起来;通过引入封闭边界形状因子将不同的注采井网类型统一起来;通过引入当量井径的概念将压裂井和水平井的井网渗流统一起来;通过引入低渗透油藏启动压力梯度将普通油藏和低渗透油藏的渗流特征统一起来。在此基础上,将不同注采井网、不同注采井型、不同投产方式、不同油藏类型的产能评价有机的统一起来,形成了一套系统的、快速而简便的评价方法,将复杂的无穷井网渗流问题用很简单的代数式和一个系数表来表征,增强了现场应用的方便性。更多还原

【Abstract】 Well pattern is the most important affecting factor to the ultimate recovery for an oilfield. The classic fluids rate forecast methods cannot meet the needs of low-permeability reservoir, horizontal wells and fracturing well patterns. Based on the theory of reservoir engineering, a series of methods have been put forward to forecast the output of oil wells for these particular well patterns.Using the mirror image, principle of potential superposition to solve pseudo steady-state flow equations of an oil well or an injection well in a closed drainage area, the output of a well in an infinite well net can be obtained. The result got from this new method is close to the result from traditional method and the relative error is less than 3.91%, but it is more simple and easy to extend.Using the Fourier transform, principle of potential superposition, trigonometric function transform, asymptotic analyses, a pressure solution of a pseudo steady-state flow model in 3D circular-boxed media has been established. Comparing with the productivity of vertical well, an equivalence radius model can be obtained. Based on the equivalence radius model, the productivity of horizontal-vertical well patterns can be established for five-spot, anti-seven-spot and anti-nine-spot well net.A productivity formula for low permeability reservoir with oil or water wells fracturing has been ascertained. This formula can be used to get the output for a vertical injection well pattern or a horizontal injection well pattern. Using the material balance method, the water breakthrough time can be obtained. The general equations of productivity and water breakthrough time considering the threshold pressure gradient of low permeability reservoir, fracture length, pattern of spacing have been established in this dissertation.This dissertation presents the comparison with some widespreadly used methods and computes the oil well output for different parameters. Methods of productivity estimation for a mixed well pattern have been used to draw up the infill development program for Daqing Yushulin oilfield.更多还原