More Results on Fracking Anisotropic Reservoirs.

in: Proc. 34th Gocad Meeting, Nancy

Abstract

The linearized Mohr-Coulomb and/or Griffiths failure criteria was investigated last year for isotropic and anisotropic rocks. These criteria assume that the intermediate principal stress has no influence on failure. This is not always the case. This work investigate additional failure criteria when applying the theory developed last year for predicting fractures during a stimulation hydraulic fracturing test. It includes new 3D failure criteria such as Hoek-Brown, the modified Lade, and the modified Wiebols-Cook criteria. Implication of rock strength anisotropy on the failure mechanism is also discussed. The hydraulic fracking GOCAD wizard was then applied on a reservoir varying various parameters such the injection pressure, the Young modulus, Poisson’s ratio, and anisotropy parameters. Fractures and their orientation were predicted on cells distant from the injection well using the unique dimensionless failure criterion developed last year. Results show that most of the fractures occurred in Mode I under the MohrCoulomb criterion, the Griffiths being rarely encountered. Statistics on the fracture orientations can be investigated using the StereoNet plug-in. The size of the damage zone such as the elongation surface and volume of the fracked zone around the injection well, plotted against the injection pressure exhibits fractal laws. These results are important for better mastering the HF technology for releasing oil and gas in low permeable reservoirs such as gas and oil shales, tight gas sands, and coal seam gas.

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BibTeX Reference

@inproceedings{RoyerGM2014,
 abstract = { The linearized Mohr-Coulomb and/or Griffiths failure criteria was investigated last year for isotropic and anisotropic rocks. These criteria assume that the intermediate principal stress has no influence on failure. This is not always the case. This work investigate additional failure criteria when applying the theory developed last year for predicting fractures during a stimulation hydraulic fracturing test. It includes new 3D failure criteria such as Hoek-Brown, the modified Lade, and the modified Wiebols-Cook criteria. Implication of rock strength anisotropy on the failure mechanism is also discussed.
The hydraulic fracking GOCAD wizard was then applied on a reservoir varying various parameters such the injection pressure, the Young modulus, Poisson’s ratio, and anisotropy parameters. Fractures and their orientation were predicted on cells distant from the injection well using the unique dimensionless failure criterion developed last year. Results show that most of the fractures occurred in Mode I under the MohrCoulomb criterion, the Griffiths being rarely encountered. Statistics on the fracture orientations can be investigated using the StereoNet plug-in. The size of the damage zone such as the elongation surface and volume of the fracked zone around the injection well, plotted against the injection pressure exhibits fractal laws.
These results are important for better mastering the HF technology for releasing oil and gas in low permeable reservoirs such as gas and oil shales, tight gas sands, and coal seam gas. },
 author = { Royer, Jean-Jacques },
 booktitle = { Proc. 34th Gocad Meeting, Nancy },
 title = { More Results on Fracking Anisotropic Reservoirs. },
 year = { 2014 }
}