Sanghyun Lee, PhD

Integrated Phase field Advanced Crack Simulator (IPACS) Ver3.0 Manual Download

Related Works


Current Research : Fracture Propagation in Porous Media using Phase Field

The design and evaluation of hydraulic fracturing jobs are critical for efficient production from shale oil and gas fields. The efficiency depends on the interaction between hydraulic and naturally occurring discrete fractures. A rigorous fracture propagation model is there fore necessary to predict fracture growth pattern in a heterogeneous, anisotropic poroelastic medium.
We study the lower-dimensional fracture surface approximated by a phase field function, where phase field is an indicator function with diffusive crack zones, which is based on gamma-convergent approximations of free discontinuity problems. The most important advantages for using the phase field is that fracture nucleation, propagation, kinking, and curvilinear paths are automatically induced in the model; post-processing of street intensity factors and re-meshing resolving the crack path are avoided.
Our phase field model solves a coupled flow problem for the reservoir and fracture domains to determine pressure distribution along the fracture with fixed stress algorithm. The fracture pressure is then assumed to be in equilibrium with the normal component of the reservoir stresses at the fracture interface for both approaches. A brittle fracture theory, as originally presented by Griffith, is invoked along with its underlying assumptions to determine a fracture growth rate and failure criterion. We further extend this model with quasi-newtonian flow and coupled with transport system for multi physics problem employing locally conservation flow by enriched Galerkin approximations.
This development is a joint effort begin carried out at the Center for Subusurface Modeling in collaboration with Andro Mikelic (Professor, at the University Lyon 1) and Thomas Wick (Assistant Professor) at Ecole Polytechnique.

0. Overview

1. History

i) Motivation ii) Modeling Background

2. Phase Field

3. Modeling and Numerical Methods

i) Geomechaincs ii) Flow iii) Transport System iv) Adaptive Mesh Refinement

5. Numerical Results: Validation

6. Numerical Examples

Multiple Fractures Joining and Branching in Heterogeneous Media 3D

Parallel Multiple Fractures Growing; Shadowed Stress Effect

7. About the code

The computational modeling of the formation and growth of the fluid filled fractures in poroelastic media is difficult with complex fracture topologies. This code predicts the fracture propagation by approximating lower-dimensional fracture surface using the phase field function with variational methods based on energy minimization. Especially, multiple fractures joining and branching in three dimensional heterogeneous media substantiate our developments (see Figure). In addition, we extend the model to track the concentration of the proppant injected with the power law non-Newtonian fluid. The algorithm has been implemented using the deal.II c++ finite element library. Parallelism is handled by using the MPI (Message Passing Interface) library and Trilinos sovler. The subdivision and mesh distribution is done by using the p4est library.