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Geomechanics and Engineering
  Volume 1, Number 2, June 2009 , pages 155-168
DOI: https://doi.org/10.12989/gae.2009.1.2.155
 


Alterations of breakdown and collapse pressures due to material nonlinearities
Pawel A. Nawrocki

 
Abstract
    Breakdown pressures obtained from the classic, linear elastic breakdown model are compared with the corresponding pressures obtained using a nonlinear material model. Compression test results obtained on sandstone and siltstone are used for that purpose together with previously formulated nonlinear model which introduces elasticity functions to address nonlinear stress-strain behaviour of rocks exhibiting stress-dependent mechanical properties. Linear and nonlinear collapse pressures are also compared and it is shown that material nonlinearities have significant effect on both breakdown and collapse pressures and on tangential stresses which control breakdown pressure around a borehole. This means that the estimates of
 
Key Words
    borehole; stress analysis; critical well pressures; material nonlinearities.
 
Address
Pawel A. Nawrocki: The Petroleum Institute, Department of Petroleum Engineering, P.O. Box 2533, Abu Dhabi, United Arab Emirates
 

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