Modeling of discrete intersecting discontinuities in rock mass using XFEM/level set approach

Abstract

Modeling of discontinuities is of major importance to assess the geomechanical behavior of oil and gas reservoirs. Traditionally, discrete discontinuities have been introduced in the numerical analysis using continuum with modified constitutive laws (e.g. multi-laminate model (ML) or zero-thickness interface elements (IE’s)). More recently, there have been several attempts to use extended finite element method (XFEM). The development of an XFEM tool could lead to improved predictions for porosity/permeability changes in coupled geomechanical reservoirs. Multiple intersecting faults are often the case in complex Reservoir and has been explored less in the literature. In this work, we have presented a novel methodology based on XFEM to analyze the behavior of multiple intersecting faults. Detailed mathematical framework has been derived by using the concept of level-set and is implemented using distributed computing to solve complex geo-mechanical problems. For validation purpose, we analyze the different examples and comparison them with standard finite element method using zero-thickness IE’s (IE-FEM).