裂缝性储层流体流动数值模拟研究进展

Advances in Numerical Simulation of Fluid Flow in Fractured Reservoirs

致密油气藏开发对于全球的油气资源供给有着重要作用,而该类储层由于天然裂缝和水力裂缝的存在和相互影响,具有强烈的非均质性和空间各向异性,加大了流体流动数值模拟的难度。本文主要从数学物理模型和数值求解方法两个角度探讨了裂缝性储层流体流动数值模拟的研究现状,现有数学物理模型大致可分为连续介质模型和离散介质模型,前者计算简便,但局部流场刻画较差,后者裂缝和流场刻画更准确,但往往计算量较大。采用传统数值求解方法,往往无法改善数学物理模型的固有缺陷,难以消除计算精度和计算效率之间的矛盾。针对上述问题,目前发展了不少新兴数值方法,但工程尺度上如何平衡复杂裂缝计算精度和效率仍是当前裂缝性储层数值模拟需要重点解决的难题,也是未来的发展趋势,实际的地下流动是一个多相—多场耦合物理过程,更符合工程场景的物理力学模型以及相应的数值方法也需要进一步思考和探索。

The development of tight reservoirs plays an important role in the global supply of oil and gas resources.Due to the existence and interaction of natural and hydraulic fractures,fractured reservoirs always show strong heterogeneity and anisotropy,which increase the difficulty of simulation on productive flow.This paper focuses on discussing the research progress of numerical simulation on fluid flow in fractured reservoirs from the perspectives of mathematical models and numerical methods.The mathematical model contains a continuous model and a discrete model.The former is simple but always fail to capture local dynamics around fractures;and the latter is accurate but always fails to avoid the huge computational cost.Traditional numerical methods are incapable of overcoming the defects inherent in the physical descriptions,and it is difficult to eliminate the contradiction between calculation accuracy and efficiency.Many new methods are developed in regard to the existing problems,but how to balance the calculation accuracy and efficiency of complex fractures on the engineering scale is still inherent to be solved.The actual underground flow is a multiphase-multifield coupling physical process.The models in line with the engineering scene and the corresponding numerical methods also need to be further studied and explored.