Journal issues: 3/2013
The best failure criteria with an analytical model for underbalanced drilling
One of the important issues in borehole instability assessments is choosing proper failure criteria. In this paper, four different failure criteria are used. These failure criteria are Mohr-Coulomb, Hoek-Brown, Modified Lade and Mogi-Coulomb failure criterion. A poroelastic model is used for calculating collapse pressure. A MATLAB code is generated for this purpose. These failure criteria are presented in the following sections briefly. The two first failure criteria ignore the effect of intermediate stress but two other failure criteria are polyaxial failure criteria and take into account the effect of intermediate stress. Collapse pressures for different inclination and azimuth which are calculated with different failure criteria are presented here. It is concluded that the failure criteria which ignore intermediate principle stress causes to overestimate collapse pressure. Modified Lade and Mogi-Coulomb criteria give the more realistic collapse pressures.
- Al-Ajmi, A. M., and Zimmerman, R. W., 2006. Stability Analysis of Vertical Boreholes Using the Mogi-Coulomb Failure Criterion. Int. J. Rock Mechanics & Mining Science, Vol. 43, РР. 1200-1211, 8 June.
- Ewy, R. T., Ray, P., Bovberg, C. A., Norman, P. D., Goodman, H. E., 2001. Open hole stability and sanding predictions by 3D extrapolation from hole-collapse tests. SPE 75328, Journal of Drilling & Completion, Volume 16, Number 4, December.
- Ewy, R.T., 1999. Wellbore-Stability Predictions by Use of a Modified Lade Criterion. SPE Drilling and completion, volume 6, PP. 85-91. June.
- Fjaer, E., Holt, R. M., Horsrud, P., Raaen, A. M., Risnes, R., 1992. Petroleum Related Rock Mechanics. 2nd edition, Elsevier Publications, PP. 1-12.
- Hoek, E., Brown, E. T., 1997. Practical estimates of rock mass strength. International Journal of Rock Mechanics and Mining Sciences, Volume 34, Number 8, PP. 1165-1186.
- Hoek, E., Brown, E. T., 1980. Underground excavations in rock. Institution of Mining and Metallurgy, London, P. 527.
- Kristiansen, T. G., 2004. Drilling wellbore stability in the compacting and subsiding Valhallfield. SPE 87221, In: Proc IADC/SPE Drilling Conf, Dallas, 2-4 March.
- Sheorey, P. R., 1997. Empirical Rock Failure Criteria, Balkema, Rotterdam, 176 p.
- Single, B., Goel, R. K., Mehrotra, V. K., Garg, S. K., and Allu, M. R., 1998. Effect of intermediate principal stress on strength of anisotropic rock mass. TunnUndergrSpaceTech, 13, РР. 71-79.
analytical model; failure criteria; poroelastic model; аналитическая модель; критерии отказа; модель пористо-упругости References to this article (GOST) H. Shahi Sooq, K. Shahbazi The best failure criteria with an analytical model for underbalanced drilling // Electronic scientific journal "Oil and Gas Business". 2013. №3. P.120-131. URL: http://ogbus.ru/eng/authors/ShahisooqH/ShahisooqH_1.pdf