The accurate information about the magnitude and orientation of in-situ stress in depth contributes to the reasonable design of drilling fluid density and borehole trajectory for avoiding wellbore failure and the associated underground complexity. The technique of estimating the magnitude of the maximum horizontal stress using the wellbore breakout observed from imaging logging has been widely recognized, but the influence of thermo-poroelastic coupling of formation rock has always been neglected. In order to accurately determine the maximum horizontal stress in depth, the wellbore breakouts during drilling process are simulated and a calculation method of the maximum horizontal stress is provided by using the thermo-poroelastic rock mechanics theory and the Mogi-Coulomb criterion. The results show that the wellbore is more prone to shear failure due to thermo-poroelastic effect of rock, and the cooling effect of drilling fluid will reduce the degree of the wellbore breakout during drilling process. The comparison between the calculation result of the maximum horizontal stress and the actual data shows that the calculation method provided is correct and feasible. Considering the thermo-poroelastic effect of rock, the magnitude of the maximum horizontal stress determined by using wellbore breakout is smaller.

有关深度现场应力的大小和方向的准确信息有助于合理设计钻井液密度和井眼轨迹，从而避免井眼破裂和相关的地下复杂性。使用从成像测井中观察到的井眼破裂来估计最大水平应力大小的技术已被广泛认可，但是地层岩石的热-孔隙-弹性耦合的影响一直被忽略。为了准确地确定最大的水平深度应力，模拟了钻井过程中的井眼破裂，并利用热-孔隙弹性岩石力学理论和Mogi-Coulomb准则提供了最大水平应力的计算方法。结果表明，由于岩石的热疏松作用，井眼更容易发生剪切破坏，钻井液的冷却作用会降低钻井过程中井眼的破裂程度。将最大水平应力计算结果与实际数据进行比较，表明所提供的计算方法是正确可行的。考虑到岩石的热多孔弹性效应，通过使用井眼破裂确定的最大水平应力的大小较小。