This paper demonstrates estimation of in-situ stresses and geomechanical parameters from four-arm caliper logging data for the Duvernay Formation in Western Canada. The four-arm caliper logs also permit identification and classification of borehole sections that display breakouts and sloughing. A poro-visco-elastic Finite Element Method simulator was developed to quantify the time-dependent borehole deformation of shale zones. The visco-elastic properties of the rock dominate time-dependent borehole deformation; pore pressure diffusion effects have negligible influence. In visco-elastic shale rocks, the estimated maximum horizontal in-situ stress is substantially smaller than results from a linear-elastic calculation; also, the estimated Young's moduli may be twice as large as results from linear-elastic models. The simulation results also indicate that rock creep effects amplify borehole breakouts, but suppress the development of drilling-induced fractures during the time-dependent borehole deformation period.

本文论证了加拿大西部Duvernay组四臂卡尺测井数据对地应力和地质力学参数的估算。四臂卡尺测井仪还可以识别和分类显示破裂和剥落的钻孔段。开发了一种粘黏弹性有限元方法模拟器来量化随时间变化的页岩带钻孔变形。岩石的粘弹特性决定了随时间变化的钻孔变形。孔隙压力扩散效应的影响可忽略不计。在粘弹性页岩中，估计的最大水平原地应力明显小于线性弹性计算得出的结果。同样，估计的杨氏模量可能是线性弹性模型结果的两倍。