Explicit versus implicit front advancing schemes for the simulation of hydraulic fracture growth

Abstract

The proper computation of the time evolution of the fracture front is the main challenge of 3D hydraulic fracture growth simulation. We discuss explicit and implicit variants of a hydraulic fracture propagation scheme based on a level set representation of the fracture. Such a scheme couples a finite discretization of the governing equations and the near-tip hydraulic fracture asymptotes. We benchmark the accuracy, robustness and stability of these different front advancing schemes on a number of test cases. Our results indicate a large computational gain of the explicit scheme at the expense of a slightly less accurate solution (few percent less accuracy over few time-steps) when crossing heterogeneities. The predictor corrector scheme combines at least a ∼ 25% computational gain while retaining the stability and accuracy of the fully implicit version of the scheme in all cases.