考虑地质及开发因素约束的三角形井网优化

在油气田开发中,影响原油采收率的因素有多种,除了油藏自身的渗透率场分布以及边界、断层、裂缝等地质因素外,还要考虑原始井位约束、布井方式、井网单元结构、注采量等开发因素的影响。在借鉴网格剖分理论中的Delaunay三角网格剖分及Voronoi图的基础上,改进Delaunay三角网格剖分只能约束采油井的局限性,使之还能约束注水井,实现在断层、生产井和注水井等约束条件下的三角形井网构建,并使用最优化方法中的PSO算法实现矢量井网的优化。结果表明,井网可以根据地质情况与油水的不同分布,以及各井网单元的尺度、方位,实现变尺度、变密度的井网布局优化。同时,考虑单元内渗透率的各向异性,通过调节注水井的井位可以实现更好的均匀驱替效果。

Triangulated well pattern optimization constrained by geological and production factors

In the process of oil and gas field development, a variety of factors can have a great effect on oil recovery.Apart from the geological factors such as permeability distribution, reservoir boundaries, faults and fractures, the production factors, such as the constraints of well location and spacing, well structure and the balance of injection and production are also very important to oil recovery. In this paper, based on the theory of Delaunay and the Voronoi graph, an improved Delaunay triangulation method was used, in which a triangulated well pattern can be constructed under the constraints of fault, production and injection wells to restrain not only injection wells but also production wells. In using an optimization method of PSO, vector well pattern can be further optimized. Well pattern can be adjusted according to the geological conditions and the distribution of oil and water, in terms of unit pattern size and well orientation, to achieve better well pattern optimization. Meanwhile, in consideration of permeability anisotropy, adjusting the locations of injection wells can obtain better oil recovery effect.