中文摘要：

塔河油田三叠系、石炭系地层钻井过程中井壁垮塌严重，井径扩大率太，严重影响了钻井效率和固井质量。利用三叠系、石炭系地层岩心，进行了地应力与岩石力学参数室内试验研究，并根据试验结果标定了岩石力学测井解释的模型，根据S68井的测井资料分析了其坍塌压力、地层破裂压力，建立了安全钻井液密度窗口。根据研究成果，确定了T453井三开井段安全钻井液密度窗口，推荐了现场钻井作业的钻井液密度程序。现场试验表明，严格按照设计的钻井液密度程序施工可避免井壁垮塌、缩径导致的起下钻遏阻以及卡钻等井下复杂情况或事故。

英文摘要：

The wellbore instability severely affects drilling efficiency and cementing quality for Permian Carboniferous formations in Tahe Oilfield. The experiments on in-situ stress and rock mechanics parameters of Permian-Carboniferous formations are performed in this paper. Based on experimental results, the logging in terpretation model of rock mechanics is calibrated. According to logging data, the collapse pressure and frac ture pressure of the Well 868 are analyzed and its safe drilling fluid density window is determined. Based on the wellbore stability analysis of Well S68, the safe drilling fluid density window, for the Well T453 is determined and the drilling fluid program is recommended. The field application shows that the drilling operation based on the designed drilling fluid program can avoid downhole risk of well wall caving in and stuck pipe, etc.