基于径向诱导裂缝的最大水平地应力预测OA

The stress polygon method,combined with borehole breakouts and induced fractures,is commonly used to constrain the range of maximum horizontal stress.However,this approach is primarily applicable to axial-induced fractures and often fails to identify well intervals where borehole breakouts and induced fractures coexist.In addition,transverse drilling-induced tensile fractures may develop along borehole walls in both vertical and horizontal wells,appearing in FMI images as sets of approxi-mately parallel and discontinuous dark short lines.These transverse drilling-induced tensile fractures can also be used to con-strain the maximum horizontal stress.In this study,both effective stress and thermal stress are considered to establish the for-mation conditions of transverse drilling-induced tensile fractures in vertical and horizontal wells.Based on this,upper and lower constraint lines for the maximum horizontal stress are derived.The results indicate that,with increasing wellbore temperature difference,the lower bound in vertical wells shifts downward,while the upper bound in horizontal wells shifts upward.A decrease in Poisson̍s ratio expands the stress polygon in vertical wells,the lower bound shifts upward and the upper bound rotates right-ward;in horizontal wells,both upper and lower bounds rotate rightward.Variations in Biot̍s coefficient mainly affect the overall range of the stress polygon,with negligible influence on the upper and lower bounds of maximum horizontal stress.By integrating these derived bounds with known minimum horizontal stress,the range of maximum horizontal stress can be efficiently determined.This method provides an extended and practical approach for constraining maximum horizontal stress in subsurface formations.