Acceleration methods for the planar 3D ILSA hydraulic fracturing model
平面3D ILSA水力压裂模型的加速方法
V. I. Shukalo, A. V. Valov, A. N. Baykin
AI总结 针对平面3D ILSA水力压裂模型计算成本高的问题,提出统一迭代方案、矩阵分裂、Anderson加速和预测-校正等加速策略,在保持精度下实现平均4倍加速,最高11倍。
Comments 56 pages, 35 figures. Submitted for publication
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水力压裂的平面3D模型在具有限制性几何假设的模型和全3D模拟器之间提供了实用的平衡,能够以适中的计算成本捕捉具有任意平面足迹的裂缝。然而,诸如处理设计优化和微型压裂测试解释等应用需要大量的模拟集合,平面3D模型的成本仍然是显著瓶颈。本文提出了平面3D隐式水平集算法(ILSA)的加速策略,以减少模拟运行时间同时保持数值精度。引入了一个统一的平面3D ILSA方案,将弹性流体动力学求解器和前沿追踪算法的嵌套循环合并为单个迭代过程。对线性化的弹性流体动力学系统应用矩阵分裂方法,将弹性算子的稠密部分移到右侧,产生一个可以更高效求解的稀疏系统矩阵。将Anderson加速纳入弹性流体动力学系统的求解中,以改善在不同裂缝几何形状下的收敛性。此外,结合所提出的方法检查了预测-校正方案,以评估它们的组合效果。在五个基准案例上,分别和组合评估了每种技术在参考和统一平面3D ILSA方案上的表现。数值实验表明,仅统一方案就实现了平均2.5倍的加速,对于沙漏几何形状达到5.7倍。所有技术的组合应用实现了平均4倍的加速,对于沙漏案例高达11倍,与参考方案相比,裂缝开度的相对差异低于5%。
Planar 3D models of hydraulic fracturing provide a practical balance between models with restrictive geometric assumptions and fully 3D simulators, capturing fractures with arbitrary planar footprints at moderate computational cost. Nevertheless, applications such as treatment design optimization and mini-frac test interpretation require large ensembles of simulations, for which the cost of planar 3D models remains a significant bottleneck. This work presents acceleration strategies for the planar 3D Implicit Level Set Algorithm (ILSA) to reduce simulation runtime while preserving numerical accuracy. A unified planar 3D ILSA scheme that consolidates the nested loops of the elastohydrodynamic solver and the front tracking algorithm into a single iterative process is introduced. A matrix splitting approach is applied to the linearized elastohydrodynamic system, moving the dense part of the elasticity operator to the right-hand side and yielding a sparse system matrix that can be solved more efficiently. Anderson acceleration is incorporated into the solution of the elastohydrodynamic system to improve convergence under varying fracture geometry. Additionally, a predictor--corrector scheme is examined with the proposed methods to assess their combined effect. Each technique is evaluated individually and in combination on both the reference and unified planar 3D ILSA schemes across five benchmark cases. Numerical experiments demonstrate that the unified scheme alone delivers an average 2.5x speedup, reaching 5.7x for the sandglass geometry. The combined application of all techniques achieves an average 4x speedup and up to 11x for the sandglass case, with the relative discrepancy in fracture aperture below 5% compared with the reference scheme.