鄂尔多斯盆地西缘冲断带深层页岩气井钻井工程中垮塌、漏失、卡钻等复杂情况频发。为保障安全高效钻井，降低勘探开发成本，早日实现该区深层海相页岩气资源的经济高效开发，基于地应力、岩石力学等室内物理实验，结合现场工程参数及塌漏信息，考虑力学弱面影响，建立西缘冲断带深井全井段地层力学参数、全井段四压力剖面模型，评价不同岩性地层力学参数分布规律，揭示了西缘冲断带深井井壁坍塌、漏失等失稳机理。结果表明：羊虎沟组以上砂泥岩地层强度较低，为20~100 MPa，拉什仲组至桌子山组灰岩强度较高，超过100 MPa。较大的水平主应力差，发育的裂缝带、煤层是诱发井壁失稳的主要原因。建立的西缘冲断带深井岩石力学性能及四压力剖面预测，可为该地区井身结构优化设计，关键工程参数选取提供科学依据。

In the drilling engineering of deep shale gas well in thrust belt of the western margin of Ordos Basin, complex cases such as collapse, leakage and stuck drilling are frequent. In order to ensure safe and efficient drilling, reduce exploration and development costs, and realize the economic and efficient development of deep marine shale gas resources in this area as soon as possible, based on indoor physical experiments of in-situ stress and rock mechanics, combined with field engineering parameters and collapse/leakage information, and considering the influence of weak surface of mechanics, formation mechanical parameter and four-pressure profile models for the whole well section of deep well in the western thrust belt were established. The distribution law of mechanical parameters of different lithologic strata was evaluated, and the instability mechanism of deep well wellbore collapse and leakage in the thrust belt of western margin was revealed. The results show that the strength of sand-mudstone strata above Yanghugou Formation is low, 20 ~100 MPa, while the strength of limestones from Lashizhong formation to Zhuozishan formation is higher, over 100 MPa. Large horizontal principal stress difference, developed fracture zone and coal seam are the main causes of wellbore instability. The established rock mechanical properties and four pressure profiles of deep wells in the western margin thrust belt can provide scientific basis for optimization design of well structure and the selection of key engineering parameters.