Abstract

To realistically simulate fluid flow in fractured rock mass, a scheme to represent the discrete fracture networks (DFN) in the numerical model is of utmost importance. In this paper we discuss a workflow to implement a field-measurement based DFN into an FEM code (COMSOL Multiphysics) by means of a MATLAB routine. This workflow is involved in the ZoKrateS project which aims at showing the feasibility to enhanced fractured carbonate Rock Mass by proppant placement for geothermal application.

The model generation is based on analytical geometry including the equations for dip, azimuth and spacing of lines. The spacing between the discontinuities and the characteristic fracture length and aperture as well as orientation serve as input parameters for the model. It is possible to generate periodic models to be able to include periodic boundary conditions in simulations. In 2D the fractures are modeled as poroelastic ellipses in a poroelastic square-matrix. We investigate hydro-mechanically triggered fluid transport in stationary fractures that are mechanically and hydraulically active.

An extension to 3D fracture networks requires an algorithm based on analytical geometry including the equations for azimuth, dip and spacing of planes. To decrease the numerical costs of the 3D simulation a diffuse interface approach is strived for, including a modified model generation.

With the numerical model generator (NUMOG) a workflow is developed which allows numerical investigations of (thermo-) hydro-mechanically triggered fluid transport in a geothermal reservoir.

Introduction

The ability to forecast thermo-hydro-mechanical properties of subsurface rock mass is of importance for geothermal reservoir application, but is also relevant for other geotechnical subsurface applications, such as carbon capture storage, hydrogen storage, hydrocarbon reservoir exploitation or deposition of nuclear waste. A suitable estimation of processes in a fractured geothermal reservoir requires adequate modeling of the fracture network. The development of a workflow that transfers field measurements into a numerical model is recently discussed, e.g. in [1, 2] where scanline data are used to create two-dimensional discrete fracture networks (DFN).

Keywords:
geologist, fracture, proppant, fluid dynamics, geology, complex reservoir, upstream oil & gas, germany government, artificial intelligence, practice iop publishing iop conf
Subjects:
Hydraulic Fracturing, Reservoir Fluid Dynamics, Unconventional and Complex Reservoirs, Non-Traditional Resources, Information Management and Systems, Fracturing materials (fluids, proppant), Flow in porous media, Naturally-fractured reservoirs, Carbonate reservoirs, Geothermal resources
This content is only available via PDF.
2021. Content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.
You can access this article if you purchase or spend a download.