Abstract: During drilling operation of Dongying formation in Bohai oilfield, mudstone is hard and brittle, hole wall collapses easily, anticline structure and rock mechanics are complex, mechanical drilling rate is low, borehole is long, hard and brittle mudstone flakes off in downhole accident. The high density of cuttings per unit annulus volume leads to pressure suppression, large torque fluctuation, and drilling jam during drilling. The drill tool breaks and falls during the processing of drilling jam, and the drilling tool of 125.94 m bottom is successfully salvaged after casing milling, and the through well cannot be reached to the end. It is decided to backfill sidetracking. After the success of sidetracking, the performance of PEM drilling fluid is optimized and new tools and technologies are used. Finally, no accident of tripping, casing, logging and cementing operation smoothly, ensure the well structure quality. The experience and lessons of drilling jam accident in this well have guiding significance and popularizing value for further deep well development in this block.

Key words: Bohai oilfield, Get stuck, Drilling tool broken, Accident treatmen, Backfill and side track

摘要： 渤海油田东营组钻井作业过程中，地层泥岩硬脆、井壁易垮塌、背斜构造和岩石力学复杂，易发生井下事故。A井实钻过程机械钻速低，裸眼段长，硬脆性泥岩片状剥落，单位环空体积岩屑浓度高，导致憋压、扭矩波动大，起钻期间发生卡钻。处理卡钻时钻具断裂落井,套铣后成功打捞起125.94 m底部钻具,后通井无法到底，决定回填侧钻。侧钻成功后优化PEM钻井液性能，创新使用新工具、新工艺。最终，实现无事故起下钻，下套管、测井及固井作业顺利，保证井身结构质量。该井卡钻事故的处理经验对该区块后续深井开发有指导意义和推广价值

关键词: 渤海油田, 卡钻, 钻具断裂, 事故处理, 回填侧钻