断溶体油藏注采井网构建方法

Constructing Optimum Injection⁃Production Well Pattern for Fault⁃Karst Reservoirs

为构建适用于碳酸盐岩缝洞型断溶体油藏的井网,增大水驱储量控制及动用程度,提高断溶体油藏的水驱开发效率,以塔河油田缝洞结构精细识别和刻画为基础,根据缝洞储集体发育和展布特征,裂缝连通状况及油水分布模式,提取出典型缝洞组合模式,建立概念模型。依据概念模型,应用数值模拟软件,建立能反映断溶体油藏特点的数值模型,考虑其平面及纵向储集体发育都具有较强的非均质性,设计了"平面上不同位置注采,纵向上不同深度注采"的井网优化方案。通过结果优选,得到适用于缝洞型断溶体油藏的最佳井网模式。研究表明,平面上,针对有一定破碎宽度的带状油藏,两翼同时注水,核部采油效果最好,针对破碎带宽度较小的板状油藏,宜采用线状井网,且注水井部署在断裂带中间的开发效果好于注水井部署在两端;纵向上,深注浅采的注采关系更有利于断溶体油藏水驱开发。

In order to construct the optimum injection⁃production well pattern suitable for fracture⁃cavity and fault⁃karst carbonate reser⁃voirs,increase the control and producing degree of reserves by waterflooding development,and improve waterflooding efficiency,a typical combined pattern of fractures and cavities was proposed,and a conceptual model was established according to the development and distri⁃bution of fracture⁃cavity reservoir,fracture connectivity and oil and water distribution in Tahe oilfield.Based on the conceptual model,a nu⁃merical model that can reflect the fault⁃karst reservoirs was established by using numerical simulation software.Considering the strong lat⁃eral and vertical heterogeneity of the reservoirs,the studies on optimizing the injection⁃production well pattern for fault⁃karst reservoirs were carried out,and a well pattern optimization plan was designed,namely“injection and production at different positions on the lateral profile,and injection and production at different depths on the vertical profile”.Finally,the optimal well pattern suitable for the fracture⁃cavity and fault⁃karst reservoirs was obtained.The result shows that on the lateral profile,for the belt⁃shaped fracture⁃cavity unit which is crushed to a certain width,the best oil production effect can be achieved in the central position if injecting water from both side wings at the same time;for the plate⁃shaped fracture⁃cavity unit crushed to a narrow width,a linear well pattern is more effective,and the development effect is better when injection wells are located in the middle of the fault zone than at both ends.Vertically,the model of deep injection and shallow production is more conducive to waterflooding development of the fault⁃karst reservoirs.