PyFrac: A planar 3D hydraulic fracture simulator

Fluid driven fractures propagate in the upper earth crust either naturally or in response to engineeredfluid injections. The quantitative prediction of their evolution is critical in order to better understandtheir dynamics as well as to optimize their creation. We present an open-source Python implemen-tation of a hydraulic fracture growth simulator based on the implicit level set algorithm originallydeveloped by Peirce & Detournay (2008). This algorithm couples a finite discretization of the fracturewith the use of the near tip asymptotic solutions of a steadily propagating semi-infinite hydraulicfracture. This allows to resolve the multi-scale processes governing hydraulic fracture propagationaccurately,evenonrelativelycoarsemeshes.Wepresentanoverviewofthemathematicalformulation,the numerical scheme and the details of our implementation. A series of problems including a radialhydraulic fracture verification test, the propagation of a height contained hydraulic fracture, the lateralspreading of a magmatic dyke and an example of fracture closure are presented to demonstrate thecapabilities, accuracy and robustness of the implemented algorithm.