裂缝性油藏改进多重子区域模型

针对现有多重子区域模型在计算裂缝单元间等效传导系数时存在的问题,采用超样本技术和体积平均法对其进行改进,改进后的模型可以有效考虑周围区域介质对裂缝单元间等效传导系数的影响,同时可以得到全张量形式的等效渗透率,在此基础上运用模拟有限差分方法构造考虑全张量形式等效渗透率的数值计算格式进行模型求解。针对不同裂缝性油藏,通过数值算例对改进模型和原始模型的准确性进行对比分析。结果表明:改进模型的计算精度比原始模型有较大提高,与离散裂缝模型参考结果基本一致,同时其计算效率高于离散裂缝模型。

An improved multiple sub-region method for flow simulation of fractured reservoirs

An improved multiple sub-region method (MSR) for flow simulation of a fractured reservoir was proposed by using an over-sampling technique and a volume averaging method. The improved MSR method can reflect the strong anisotropy in fractures and can effectively simulate the effects of nearby sub-region on the transmissibility of the fractures. A mimetic finite difference method (MFD) was used for the numerical solution, which has excellent local conservation features and good applicability for the complex unstructured grid and permeability tensors. Several case studies were conducted to verify the accuracy and applicability of the improved method. The results obtained using the improved model agree well with those obtained using a conventional discrete fracture model, and the calculation efficiency of the improved model is higher than that of the discrete fracture model.