A Micromechanical Model to Estimate Borehole Collapse Pressure

  • Nader Ghasempour PhD candidate Department of mining Engineering, University of Tehran, Tehran, Iran
  • Mahdi Moosavi Associate Prof., School of Mining Engineering, The University of Tehran, Tehran, Iran
  • Mohammad Ali Aghighi Assistant professor Imam Khomeini International University Qazvin, Iran

Abstract

Borehole collapse is predicted by common rock failure criteriadespite they give conservative results due to some simplificationof rock behavior. It is the source of many difficulties in implementationof oil well, underground structures and foundations.Utilizing damage theory could improve the conservancy of rockfailure criterion. Damage theory considers loss of functionrather than loss of strength. Unlike criteria which were derivedfrom plasticity that assume yielding point as the limit of functionalityof rock, damage theory uses a state between failureand yielding in stress-strain diagram as the limit of the rockapplicability. In this study, a new model is proposed to predictminimum borehole pressure based on rock damage theory. Themodel is verified by actual wellbore data. The proposed modelpredicts minimum borehole pressure close to actual data andmore accurate than Mohr-coulomb and Mogi-Coulomb criteria.

Keywords

collapse pressure, wellbore stability, rock damage, rock micromechanics
Published
10-02-2017
How to Cite
GHASEMPOUR, Nader; MOOSAVI, Mahdi; AGHIGHI, Mohammad Ali. A Micromechanical Model to Estimate Borehole Collapse Pressure. Periodica Polytechnica Civil Engineering, [S.l.], v. 61, n. 3, p. 581-589, feb. 2017. ISSN 1587-3773. Available at: <https://pp.bme.hu/ci/article/view/9979>. Date accessed: 25 sep. 2017. doi: https://doi.org/10.3311/PPci.9979.
Section
Research Article