三重介质底水气藏非稳态水侵规律研究  

Studies on Transient Water Invasion Mechanism of the Triple Porosity Gas Reservoir with Bottom-water

作　　者：樊怀才[1] 钟兵[1] 刘义成[1] 杨学锋[1] 冯曦[1] 邓惠[1] 

机构地区：[1]西南油气田分公司勘探开发研究院,四川成都610041

出　　处：《天然气地球科学》2015年第3期556-563,共8页Natural Gas Geoscience

基　　金：国家科技重大专项"复杂碳酸盐岩气藏开发技术"(编号:2011ZX05015-03);西南油气田分公司2012年博士后科研项目"三重介质底水气藏治水开发机理研究"(编号:20120305-12)联合资助

摘　　要：裂缝水窜是三重介质底水气藏主要的水侵特征,水侵规律受储层特征、水体大小及生产压差影响显著。通过将气藏简化为"上气下水"的圆柱形物理模型,并将底水侵入气藏的过程抽象为溶洞系统和基岩系统中的地层水向裂缝系统窜流,沿裂缝系统经气水界面侵入气层,建立了底水非稳态水侵渗流数学模型,采用分离变量法、贝塞尔函数及拉普拉斯变换等现代数学分析方法对模型进行求解,求取了该模型裂缝系统压力的精确解,并利用加权平均法获得了气水界面处的平均压力。在此基础上,运用Duhamel原理建立了气水界面处水侵速度和气藏累计水侵量的计算方法。通过数值反演得到了三重介质底水气藏非稳态水侵典型曲线,将非稳态水侵过程划分成"裂缝系统早期线性流、裂缝系统径向流、溶洞系统向裂缝系统窜流、缝—洞系统径向流、基质系统向裂缝系统窜流及孔—缝—洞系统径向流"6个阶段,分析了水体大小、储层物性、裂缝系统水平渗透率和垂直渗透率之比及生产工作制度对非稳态水侵规律的影响,研究方法和结果对合理分析三重介质底水气藏水侵动态特征及优化气藏治水开发方案具有一定的指导意义。Fracture water breakthrough is the main characteristics of the water influx in the triple porosity gas reservoir with bottom-water. The law of water invasion is influenced by the reservoir characteristics, the size of the bottom aquifer and the producing pressure. Based on the characteristics of water invasion in the triple medium bottom-water gas reservoir, the gas reservoir is simplified as a cylindrical physical model that is ＂the gas horizon over the aquifer＂. In this model,the seepage flow in the triple porosity is abstracted as a process that water in the cave system and the matrix system channels to fracture system,and is produced through the fracture system. A transient seepage mathematical model for aquifer triple is established,and an accurate solution to the pressure of the fracture system is obtained by means of modern mathematical methods including the method of separation of variables, Bessel function and Laplace transformation,and the average pressure of gas-water interface is obtained by using the area weighted technique. Furthermore, the method of computing the water invasion rate on the gas-water interface and cumulative water influx that intrudes into gas reservoir is established by applying the Duhamel principle. The typical curve of transient water invasion in the triple porosity gas reservoir with bottom-water is plotted by means of the numerical inversion, the process of bottom water invasion is divided into six sections, including the early linear flow of fracture system,radial flow of fracture system,the channeling flow from cave system to fracture system, the radial flow of fracture and cave system, the channeling flow from matrix system to fracture system and the radial flow of the whole system. The influence on transient water invasion mechanism is analyzed such as aquifer size, interstitial physical-property parameters, the ratio of the horizontal permeability and vertical permeability, production system and so on. The methods and results of this research contribute to reasonable

关 键 词：三重介质 底水气藏 非稳态水侵 渗流模型 水侵量 

分 类 号：TE357.1[石油与天然气工程—油气田开发工程]