基于三维嵌入式离散裂缝模型的致密油藏体积压裂水平井数值模拟

3D EDFM⁃Based numerical simulation of volume fractured horizontal wells in tight oil reservoirs

针对致密油藏体积压裂水平井裂缝建模困难、传统嵌入式离散裂缝模型(Embedded Discrete Fracture Model,EDFM)对三维空间中裂缝复杂的立体分布及复杂形状难以准确刻画、体积压裂致密油藏开发动态模拟及产能评价困难等问题,基于三维笛卡尔网格及裂缝面的参数化表征方法,考虑重力、致密油藏非线性渗流特征及应力敏感特征,建立了适用于任意形状倾斜裂缝面的网格剖分方法及三维嵌入式离散裂缝模型。通过与商业软件Eclipse计算结果对比和对新疆油田一口井的实际生产数据拟合验证了模型的准确性和可靠性。基于该模型,进行了体积压裂致密油藏产能影响因素分析。结果表明:三维嵌入式离散裂缝模型能较好地表征流体在具有复杂空间分布形态及复杂裂缝形状缝网中的渗流过程,可以应用于体积压裂致密油藏的开发动态模拟。研究成果为致密油藏水平井体积压裂提供了理论依据。

In view of difficulty in modeling horizontal well fractures in tight oil reservoirs and difficulty of traditional embedded discrete fracture model(EDFM)in accurately describing complex 3D distribution and geometry of frac‑tures in 3D space,it is difficult to simulate production performance and evaluate productivity of tight oil reservoirs.Based on 3D Cartesian grid and fracture surface parameterization method,a mesh generation method and 3D EDFM suitable for arbitrary geometry inclined fracture surface are established considering gravity,non-linear flow charac‑teristics and stress sensitive characteristics of tight oil reservoir.Accuracy and reliability of proposed model are veri‑fied by comparing the results with commercial software Eclipse and fitting actual production data of a well in Xin‑jiang Oilfield.Based on this model,the factors affecting productivity of volumetric fractured tight oil reservoir are analyzed.The results show that 3D embedded discrete fracture model can better characterize fluid flow behavior in fracture network with complex spatial distribution and fracture geometry,and can be applied to development perfor‑mance prediction of volumetric fractured tight oil reservoir.The research results provide theoretical basis for volu‑metric fracturing of horizontal wells in tight oil reservoirs.