SOUTHWEST RESEARCH INSTITUTE

Publications

Contact Us

SwRI Information

Home

3DStress^® software is an advanced tool to interactively analyze the tendency for faults and fractures to slip or dilate based on a user-specified three-dimensional (3D) stress state.

3DStress displays faults and fractures in three-dimensional (3D) space and colors them based on:

• Slip Tendency

  Slip tendency is the ratio of the shear stress to the normal stress on a fault surface:

  

• Dilation Tendency

  Dilation tendency is the likelihood for a fault or extension fracture to dilate based on the 3D stress conditions and is computed as:

  

3DStress provides an interactive tool for determining stresses on faults and fractures, used in trap assessment, planning wells, and characterization of faults and fractures in hydrocarbon and geothermal reservoirs (top figure). 3DStress is also used in evaluating stability of drifts and other underground excavations in faulted and fractured rock (lower figure).

• Leakage factor

  Leakage factor is similar to dilation tendency, but it takes into account detailed information on fluid pressure and tensile strength of fault-zone or fracture-filling material.

• Slip Direction

  In addition to slip and dilation tendency, 3DStress computes the expected slip direction by finding the maximum shear stress for the fault surface.

The 3DStress software provides user input, computation, and data visualization tools to analyze the tendency for faults and fractures to slip, dilate, or leak, and it also creates an interactive environment with various stress conditions. 3DStress, developed at Southwest Research Institute (SwRI), performs three primary tasks:

• Provides a user interface for interactive control of the input stress orientations and magnitudes

• Computes slip tendency, dilation tendency, leakage factor, and slip direction from the input stress parameters and fault surface orientation

• Displays 2D trace maps, 3D cutoff lines, or 3D surface representations of faults and fractures colored by slip tendency, dilation tendency, or leakage factor

3DStress provides a user interface for interactive control of the input stress orientations and magnitudes

3DStress Interactivity

3DStress, users can interactively control the stress field and see the results on the displayed faults and fractures. In addition, 3DStress has a lower hemisphere equal-angle stereographic projection display. This stereonet displays orientations of fractures and faults and is also colored based on the computed slip tendency, dilation tendency, or leakage factor.

3DStress utilizes user-defined stress fields to compute the likelihood of fault slip or fracture dilation based on the orientation of the fault or fracture.

Slip tendency fault map of Yucca Mountain Region. Slip tendency is calculated using the present day stress field. NNE striking faults have highest slip tendency.	Fault map of Yucca Mountain region shows faults colored by their values of dilation tendency using the present-day stress field.

In complexly faulted areas, 3DStress can be used to distinguish populations of faults that may have formed contemporaneously under past stress conditions. Alternatively, 3DStress can be used to interpret the contemporary stress field by interactively optimizing the slip tendency and slip directions on known active faults or to identify faults that are likely to be active or inactive in a known stress field.

In addition to determining relative tendency of faults and fractures to slip or dilate, 3DStress provides a powerful tool for predicting:

• Fault sealing

• Hydrocarbon migration routes

• Evaluating potential fracture controlled permeability in fractured rock

Uses of the 3DStress Software:

• Oil and gas prospect risk assessment

• Calculation of slip vectors for 3D reconstructions

• Planning production strategy for fractured reservoirs

• Stress state sensitivity analysis

3DStress is under constant development; contact us for new functionality available through our consulting services.

References and Abstracts

Read more about 3DStress in "Predicting a Fault's Next Move," published in the Summer 1996 issue of Technology Today^®.

For more information about the 3DStress application or Earth sciences and engineering capabilities at SwRI or how you can contract with SwRI, please contact please contact David Ferrill, Ph.D. at dferrill@swri.org or  (210) 522-6082, or Alan Morris, Ph.D. at amorris@swri.org or (210) 522-6743.

| Department of Earth, Material and Planetary Sciences | Geosciences and Engineering Division | SwRI Home |

Southwest Research Institute® (SwRI®), headquartered in San Antonio, Texas, is a multidisciplinary, independent, nonprofit, applied engineering and physical sciences research and development organization with 11 technical divisions.

April 17, 2009