Imperial College London
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Professor of Rock Mechanics

Faculty of Engineering, Department of Earth Science & Engineering

Chair in Rock Mechanics
 
 
 
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Contact

 

+44 (0)20 7594 7412r.w.zimmerman

 
 
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Location

 

2.38DRoyal School of MinesSouth Kensington Campus

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Summary

 

Publications

Citation

BibTex format

@article{Setiawan:2018:10.1016/j.ijrmms.2018.10.033,
author = {Setiawan, NB and Zimmerman, RW},
doi = {10.1016/j.ijrmms.2018.10.033},
journal = {International Journal of Rock Mechanics and Mining Sciences},
pages = {313--322},
title = {Wellbore breakout prediction in transversely isotropic rocks using true-triaxial failure criteria},
url = {http://dx.doi.org/10.1016/j.ijrmms.2018.10.033},
volume = {112},
year = {2018}
}
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RIS format (EndNote, RefMan)

TY  - JOUR
AB  - This paper presents a unified approach through which the influence of the elastic and strength anisotropy on wellbore instability can be thoroughly examined. The stresses at the wellbore wall are first calculated using the Lekhnitskii-Amadei solution, which accounts for elastic anisotropy. Then, shear failure is treated by combining the Mogi-Coulomb criterion for intact rock, with the Jaeger plane of weakness concept. The developed model accounts for all three principal stresses in predicting the onset of shear failure.The results of the specific case investigated show that rock elastic anisotropy induce higher stress concentrations. The difference, compared with the stresses found using the isotropic elastic model, could reach as high as 25% for the highest degree of anisotropy that might be expected for rocks of practical interest. The strengthening effect of the intermediate stress, as reflected in the Mogi-Coulomb criterion, reduces the required mud weight density by approximately 1.0 pounds-per-gallon (ppg). Furthermore, it is demonstrated that the risk posed by bedding slippage, for a wellbore with an inclination between 15° and 50° from the vertical, is masked when an isotropic elastic stress model is used. In contrast, the fully anisotropic model shows that an extra mud weight of approximately 4.5ppg would be required, in order to avoid bedding plane slippage for the case under investigation. Although these results apply for a particular choice of strength properties and elastic properties, they give an indication of the implications of fully accounting for anisotropy and the effect of the intermediate stress when doing borehole stability analysis.
AU  - Setiawan,NB
AU  - Zimmerman,RW
DO  - 10.1016/j.ijrmms.2018.10.033
EP  - 322
PY  - 2018///
SN  - 0020-7624
SP  - 313
TI  - Wellbore breakout prediction in transversely isotropic rocks using true-triaxial failure criteria
T2  - International Journal of Rock Mechanics and Mining Sciences
UR  - http://dx.doi.org/10.1016/j.ijrmms.2018.10.033
UR  - http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000452314500028&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=1ba7043ffcc86c417c072aa74d649202
UR  - https://www.sciencedirect.com/science/article/pii/S1365160918304817
UR  - http://hdl.handle.net/10044/1/83242
VL  - 112
ER  -
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