标题： 非线性消去预条件技术在裂隙多孔介质输运问题中的应用 显示英文标题

标题： Adaptive Nonlinear Elimination Preconditioning for Transport in Fractured Porous Media

摘要： 由于序列隐式（SI）公式能够将油藏模拟问题分解为独立的流动和输运子问题，从而可以使用专门针对每个子问题设计的求解器，因此其兴趣日益增加。 这种分离通常会提高求解器的效率和灵活性，特别是在弱耦合系统中。 然而，对于裂隙油藏，即使分解后的子问题也可能产生非线性刚性系统。 这一点在输运子问题中尤为明显，其中由裂隙引起的非线性不平衡常常导致牛顿收敛性差，包括迭代失败和频繁的时间步削减。 为了解决这个挑战，我们提出并研究了一种自适应非线性消除（NE）预处理精确牛顿算法，该算法专门针对从裂隙多孔介质中两相流的序列分裂产生的输运子问题。 所提出的方法通过涉及离散裂隙网络的一系列水驱案例进行了评估。 与标准牛顿法相比，自适应NE预处理算法始终表现出更好的收敛特性和计算效率。 显示英文摘要

摘要： Sequential implicit (SI) formulations are gaining increasing interest due to their ability to decouple reservoir simulation problems into distinct flow and transport subproblems, allowing for the use of specialized solvers tailored to each. This separation often improves solver efficiency and flexibility, especially in weakly coupled systems. However, for fractured reservoirs, even the decoupled subproblems may generate nonlinearly stiff systems. This is specifically evident in the transport subproblem, where fracture-induced non-linearity imbalances often lead to poor Newton convergence, including failed iterations and frequent timestep cuts. To address this challenge, we propose and investigate an adaptive Nonlinear Elimination (NE) preconditioned exact Newton algorithm specifically tailored to transport subproblems that arise from the sequential splitting of two-phase flow in fractured porous media. The proposed method is evaluated through a series of waterflooding test cases involving discrete fracture networks. The adaptive NE-preconditioned algorithm consistently demonstrates improved convergence behavior and computational efficiency compared to standard Newton.