缝洞型碳酸盐岩油藏数值模拟基础理论与应用

BASIC THEORY AND APPLICATION OF NUMERICAL SIMULATION IN FRACTURED-VUGGY CARBONATE RESERVOIR

现有油藏数值模拟技术均为以多孔连续介质为理论基础，以达西方程、连续性方程为核心的数值模拟技术。缝洞型油藏流动特征复杂，不仅存在多孔连续介质渗流特征，还存在离散介质N—S流特征，现有的油藏数值模拟技术不适用。针对缝洞型碳酸盐岩油藏储层特征，划分了缝洞型油藏介质类型；依据表征单元体基础理论，建立了缝洞油藏连续介质与离散介质耦合计算的理论方法，形成了渗流与缝洞流的流体流动方程组；在数值计算方法上，解决了洞穴流内速度与压力非显式矢量计算求解难题，编写了计算机程序。通过塔河油田应用，揭示了缝洞型油藏开发动力学机理，提出了注水开发模式，实践后产生了明显的经济效益。

Current numerical reservoir simulation technologies are the numerical simulation technologies which completely take the porous continuous medium as the theoretical basis and Darey equation and continuing equation as the core. Fractured-Vuggy reservoirs have complex flow characteristics, which have not only the continuous porous medium seepage characteristics but the discrete medium N-S flow characteristics as well, therefore, current technology can not deal with the fractured-vuggy reservoirs. Aiming at the reservoir characteristics of fractured-vug- gy carbonate reservoirs, the media type of fractured-vuggy reservoirs is classified. According to the basic theory of representative elementary volume （ REV } , the theoretical method for coupling calculation of continuous medium and discrete media in fraetured-vuggy reservoir is established, and meanwhile the fluid flow equation set of seepage and fluid flow in fractures and cavities is created. In the aspect of numerical calculation method, this theory solves the problem in seeking the solution of flow velocity and pressure non-explicit vector calculation in cavity, and a computer program based on this theory is complied. Through the application in Tahe Oilfield, it reveals the dynamics mechanism of the fractured-vuggy reservoir development, and the pattern of waterflood development is proposed.A good economic benefit has been obtained after the practice.