天然微裂缝发育的低渗透油藏数值模拟

Numerical simulation on low-permeability reservoir with abundant natural micro-fractures

由于天然微裂缝难以识别和定量描述,在建立定量化的微裂缝地质模型时,采用双重介质模型进行油藏数值模拟研究存在较大困难,注水开发中微裂缝的动态开启和闭合也难以进行模拟研究。根据等值渗流阻力法原理,利用微裂缝的统计特征参数,如裂缝线密度、裂缝长度等建立天然微裂缝发育低渗透油藏的等效连续介质地质模型,根据地应力和现场注水指示曲线,建立了裂缝传导率与地层压力的方程,可以等效模拟注水开发中的微裂缝开启和闭合现象。以长庆西峰油田西137井区为例,模拟研究了井网及注水开发动态,与现场动态分析结果一致。

It is very difficult to do numerical simulation on oil reservoir using a double-permeability（or double-porosity） system,because it is difficult to quantitatively identify and describe the natural micro-fractures.It is also difficult to simulate the phenomenon of the dynamic opening and closing of micro-fractures.The geologic model of the equal-effective continuous medium was built according to the principle of equal filtration resistance and using the statistical data of the fractures,such as linear density of fracture, length of fracture. The equations of fracture conductivity and reservoir pressure were built according to the field stress and the indicating curves of water flooding. The status of dynamic opening and closing of the micro-fractures can be simulated using those equations. The X137 Block in Xifeng Oilfield was simulated to optimize the well pattern and water-flooding situation. The simulation result consists with the result of the dynamic field analysis.