University of Texas at Austin

Coupled Fluid Flow and Geomechanical Modeling

Synopsis: Coupled Fluid Flow and Geomechanical Modeling to Examine Fault Activation and Induced Seismicity near Azle, Texas

Project Status: active

Funding Source: 100% TexNet

Research Leaders: Akhil Datta-Gupta, Jihoon Kim and Michael J. King (Texas A&M University)

Project Start: 2Q2016

Project Interface: Project interfaces closely with Ft. Worth Basin Earthquake Characterization, Faults and Geomodels, Pore Pressure Analysis of Ft. Worth Basin, Geomechanics of Fault Reactivation, and Multi-Institutional and Industrial Collaboration for Geomechanical and Seismicity Assessment of the Ft. Worth Basin

Expected research outcomes:

  • Assessment of Fault activation by coupled flow and geomechanics
  • Modeling of potentially induced seismicity in the area of Azle, TX
  • Reservoir characterization sensitivities

In November 2013 a series of earthquakes occurred near a fault system in Azle, TX. This seismicity is suspected to be induced by brine production and waste-water injection in the vicinity of the fault system. Small changes in stress by changes in pore-pressure can activate a fault system, especially if the fault is almost critically-stressed. This phenomenon can be modelled using coupled fluid flow and geomechanics. However, no systematic modeling of coupled flow, geomechanical effects and induced seismicity has been carried out near the Azle site. We propose modeling of fluid flow through complex faulted systems, visualizing transport across faulted systems using streamlines, fault activation using coupled fluid flow-geomechanical simulation, and potential induced seismicity through calculation of seismic moments.

A coupled geomechanical and flow reservoir simulation may capture the interaction of the mechanisms described above. However, the predictive ability of the model will be limited by the formation characteristics, which includes its structure, stratigraphy, local and regional stress state, fault geometry, fault seal, and the petrophysical and geomechanical properties of the formation. Some few of these characteristics may be known or estimated by prior geologic modeling but with considerable uncertainty. The impact of these characteristics will need to be evaluated using sensitivity studies. These studies should acknowledge three scales of unknowns. The regional scale will control the stress boundary conditions on the geomechanical calculation. The stratigraphic scale will describe the systematic variation of properties throughout the formation. The local scale of heterogeneity will describe the variability of properties within the strata of a formation. All may influence the impact of predictions of fault activation and induced seismic activity.