Analytical investigations of in situ stress inversion from borehole breakout geometries

作     者：Zizhuo Xiang Taehyun Moon Joung Oh Guangyao Si Ismet Canbulat Zizhuo Xiang;Taehyun Moon;Joung Oha;Guangyao Si;Ismet Canbulat

作者机构：School of Minerals and Energy Resources EngineeringUniversity of New South WalesSydneyNSW2052Australia HNTB Corporation3505th Ave.58th FloorNew YorkNY10118USA 

出 版 物：《Journal of Rock Mechanics and Geotechnical Engineering》 (岩石力学与岩土工程学报（英文版）)

年 卷 期：2024年第16卷第7期

页      面：2375-2387页

核心收录：

学科分类：08[工学] 080104[工学-工程力学] 0815[工学-水利工程] 0801[工学-力学（可授工学、理学学位）] 

基　　金：funded by the Australian Coal Industry’s Research Program(ACARP Grant No.C26063) 

主　　题：Borehole failure In situ stress estimation In situ horizontal stress ratio Conformal mapping Complex variable method Breakout stabilisation 

摘      要：This study aims to investigate the feasibility of deriving in situ horizontal stresses from the breakout width and depth using the analytical ***-three breakout data with different borehole sizes were collected and three failure criteria were *** on the Kirsch equations,relatively accurate major horizontal stress(sH)estimations from known minor horizontal stress(sh)were achieved with percentage errors ranging from 0.33%to 44.08%using the breakout *** Mogi-Coulomb failure criterion(average error:13.1%)outperformed modified Wiebols-Cook(average error:19.09%)and modified Lade(average error:18.09%)failure ***,none of the tested constitutive models could yield reasonable sh predictions from known sH using the same approach due to the analytical expression of the redistributed stress and the nature of the constitutive *** consideration of this issue,the horizontal stress ratio(sH/sh)is suggested as an alternative input,which could estimate both sH and sh with the same level of ***,the estimation accuracies for both large-scale and laboratory-scale breakouts are comparable,suggesting the applicability of this approach across different breakout *** breakout depth,conformal mapping and complex variable method were used to calculate the stress concentration around the breakout tip,allowing the expression of redistributed stresses using binomials composed of sH and ***,analysis of the breakout depth stabilisation mechanism indicates that additional parameters are required to utilise normalised breakout depth for stress estimation compared to breakout *** parameters are challenging to obtain,especially under field conditions,meaning utilising normalised breakout depth analytically in practical applications faces significant challenges and remains infeasible at this ***,the normalised breakout depth should still be considered a critical input for any empirical and statistical stres