【作者】 卢泉杰；

【导师】 姚军；

【作者基本信息】 中国石油大学 ， 油气田开发工程， 2008， 硕士

【摘要】 网格是油藏数值模拟的基础,网格质量的好坏直接影响着数值模拟结果的精确度,基于非结构网格系统的数值模拟技术目前已成为油藏模拟领域中的一个重要发展方向。角点网格、PEBI网格和CVFE网格具有非常灵活的特性,能够精确描述油藏的复杂形态(边界、断层、裂缝等),模拟效果更加真实。这三种网格都可以在三角形网格的基础上生成,因此高质量的三角形网格的生成方法研究显得尤为重要。本文提出了一种满足Delaunay条件的三角形网格系统生成方法——控制子域Delaunay三角化方法,与经典三角化方法的对比研究表明,该方法节省了网格点数、提高了运算速度,且生成的网格质量更高。在生成的Delaunay三角网基础上,将相邻三角形的公共边去掉就形成四边形网格系统,将相邻三角形的外心连接起来就形成PEBI网格系统,将三角形重心和各边中点连接起来就形成CVFE网格系统,另外还需要对边界进行特殊处理。平面四边形网格通过引出纵向坐标线和定义每个层面上的角点深度,可以生成三维角点网格系统,该网格系统是目前应用最多的非结构网格系统。应用PEBI网格系统和CVFE网格系统,对具有复杂边界形状、裂缝和断层不规则分布的油藏进行了网格剖分,使网格沿不规则边界及裂缝、断层走向分布,与笛卡尔网格和角点网格相比,剖分过程更加灵活,剖分结果更加接近油藏实际。基于几种优选的网格生成方法,特别针对具有不规则形状的复杂油藏编制了涵盖D-三角形网格系统、角点网格系统、PEBI网格系统和CVFE网格系统的网格生成软件。基于PEBI网格建立了二维两相油藏数值模型,并进行了求解,编制了数值模拟器,验证了模拟器的正确性。应用该模拟器建立了三个数值模拟实例,实例1表明PEBI网格有效降低了网格取向效应;实例2表明PEBI网格可以更加精确地模拟复杂油藏中断层、高渗透条带对渗流的影响;在实例3中,成功的将PEBI网格应用于五点法井网的油藏数值模拟,进一步验证了模拟器的正确性和可靠性。更多还原

【Abstract】 Grid generation is the base of simulation and the quality of gird has direct influence upon the precision of simulation. At present, numerical simulation based on unstructed grid system is an important tendency of reservoir simulation and an indispensable functional module of simulation software. Corner Point Geometry, PEBI Grid, CVFE Grid are so flexible that they can exactly describe reservoirs with complex configuration (boundary, fault, fracture). It is important to research the method of creating high quality triangular grid because these three kinds of gird can be created on the basis of triangular gird. This paper presents a creating method meeting Delaunay condition-Controlled Subdomain Delaunay Triangulation Method. This method can save grid number, speed computation and create better grid in contrast with other methods. PEBI grid system is formed by connecting circumcenters of adjacent triangles and link the barycenter with midpoints of each edge to shape CVFE grid system, furthermore, the edges should be specially disposed. Three-dimensional Corner Point Geometry grid system is the most mature unstructed grid system and it can be created directly from quadrilateral grid system. PEBI and CVFE grid system are utilized in this paper to the reservoirs with complex shaped boundary, fractures and faults. The results demonstrate that it is more accurate than Cartesian grid and corner point geometry. The method of generating corner point geometry system is studied in this paper which is also evaluated through comparison with corner point geometry modular of the existing commercial simulation software. Furthermore, grid generation software covering Delaunay triangulation, PEBI grid, CVFE grid and corner point geometry is programmed especially for complex reservoirs with irregular boundaries. Three simulation examples are erected with this simulator: example 1 shows that PEBI gird system effectively reduces grid orientation effects; example 2 demonstrates PEBI grid can exactly simulate the effect of fault and high permeable strip to flow in complex reservoir; example 3 successfully used PEBI grid in five-spot pattern which verified the validity and reliability of this simulator.更多还原