Simulation of Coupled Single-Phase Flow and Geomechanics in Fractured Porous Media
Abstract/Contents
- Abstract
- Accurate predictions of the complex interactions between fluid-flow and mechanical deformation in fractured geologic formations is of interest in a wide range of reservoir engineering applications including subsurface CO2 sequestration, heavy-oil recovery, and wellbore stability. In this report, we describe a fully implicit method for coupled geomechanics and fluid flow in naturally fractured porous rocks. Specifically, we study single-phase fluid flow and poroelastic mechanical deformation for two-dimensional domains. A Discrete Fracture Model (DFM) with a static unstructured computational grid is employed, in which the fractures are represented explicitly as low-dimensional objects embedded in the matrix. The fracture segments lie at the interface between matrix elements (control volumes). The combination of unstructured grids and a DFM-based description allows for accurate representation of the complex geometry and the wide range of length-scales often observed for naturally fractured formations. We assume that the deformations are small, so that the computational grid remains as a function of time. We also assume that all the fractures are already present and represented explicitly, and that no failure (i.e., fracture propagation) will take place. A low-order finite-volume method is used to discretize the mass conservation equations of the matrix and the fractures. A finite-element method is used for the mechanics problem, in which a double-node numbering scheme is used for the fracture segments. The double nodes are enriched with additional degrees of freedom that are chosen to enforce the equilibrium conditions at the two fracture surfaces represented by the segment. The appropriate equilibrium conditions at discrete fracture segments and how to enforce them in the numerical model are discussed in detail. Fully implicit coupling of the flow and mechanics problems is performed by updating the primary unknowns, namely, displacement (vector) and pressure, until convergence is achieved. We validate the numerical model using several simple test cases of two-dimensional domains with one, or several intersecting, fractures for a variety of boundary conditions and matrix-fracture properties.
Description
| Type of resource | text |
|---|---|
| Date created | August 2011 |
Creators/Contributors
| Author | Levonyan, Karine |
|---|---|
| Primary advisor | Tchelepi, Hamdi A. |
| Degree granting institution | Stanford University, Department of Petroleum Engineering |
Subjects
| Subject | School of Earth Energy & Environmental Sciences |
|---|---|
| Genre | Thesis |
Bibliographic information
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Preferred citation
- Preferred Citation
- Levonyan, Karine. (2011). Simulation of Coupled Single-Phase Flow and Geomechanics in Fractured Porous Media. Stanford Digital Repository. Available at: https://purl.stanford.edu/sp155vm6775
Collection
Master's Theses, Doerr School of Sustainability
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