Description

As the oil industry matures, "difficult" reservoirs, such as fractured reservoirs, become more economically attractive. Fractures are also increasingly viewed as having a significant role in successful secondary recovery of resources as well as in near-surface environmental remediation. Unfortunately, natural fracture patterns are difficult to characterize in the subsurface. Fracture systematics are not well-constrained from wellbore or seismic data. This difficulty in fracture characterization poses serious challenges for exploration, risk assess ment, development, and accurate reservoir simulation and management. More complex characteriza tions of the unsampled region between wells can be made using stochastic methods, but these methods are often generated patterns that are not realistic-looking. The results are only as good as the base statistical data, which may come from a different geological province or different rock type than the reservoir in question.

A promising technique for reducing uncertainty in fracture characterization is embodied in JOINTS, a geomechanics-based model where a physical understanding of the fracturing process is combined with measurements of mechanical properties of rock and geologic deformation history to predict fracture network characteristics. This process-oriented approach provides a theoretical basis for deciding what types of fracture attribute distributions are physically reasonable, and how attributes such as length, spacing, and aperture are interrelated. JOINTS simulates subcritical and critical opening-mode fracture growth and can provide a combined prediction of all fracture attributes and their spatial distribution that can be used in discrete fracture flow modeling or in permeability upscaling for more traditional finite difference simulators.

Benefits

• Designed to run in the Windows environment
  
• Has an easy-to-use spreadsheet/macro interface
  
• Can be run in two modes--with or without graphics (static or animated)
  
• Analyses of results have shown vast improvement over common practice
  

Features

• Program could also be applied to characterizing fracture patterns for environmental problems in fractured rock (beyond patterns in outcrop and subsurface reservoirs).
  
• Uniquely, the generation of fracture patterns is based on widely accepted and fundamentally reliable principles of fracture mechanics and elasticity (thus, it has predictive capability and is constrained by laws of physics).
  

Market Potential/Applications

Major oil & gas companies would be interested in using this program internally (ChevronTexaco, Shell, ExxonMobil). The oilfield service companies (Halliburton, Schlumberger) may have an interest in reselling the code, either as product or as a part of the fractured reservoir characterization service.

Contact:

University of Texas,
Austin, USA
Website : www.otc.utexas.edu