七里北101井气体钻井提高钻速试验研究

STUDY ON GAS DRILLING TECHNOLOGY FOR IMPROVING DRILLING RATE IN QILIBEI 101 WELL

遭遇大段研磨性强、可钻性差的难钻地层,钻井液钻井钻速慢,井下事故频繁,建井周期长,已成为制约深层油气资源有效勘探开发的瓶颈。采用气基流体作为钻井循环介质,通过改变井底应力状态、消除压持效应、降低岩石强度和研磨性、延长钻头寿命和提高井底清洁效率可有效提高钻速。七里北101井采用气体钻井进行提速的试验结果表明,气体钻井可提高钻速1.7～13.3倍,有效减少钻具事故和克服井漏,大幅缩短建井周期;钻前进行井壁稳定性、地层出水和地层出气分析并配套相应的井身结构设计和钻进方案设计,钻进过程进行气体监测和设备工具配套有利于保证气体钻井安全顺利进行。

Long length stiff formation with strong abrasive property, poor drillabillity, low mud drilling rate, frequent downhole drilling failures and long construction cycle has restricted the exploration and exploitation of deep oil and gas reservoir. Drilling with gas-based fluids can improve drilling rate efficiently through changing bottom hole stress state, elimination of chip hold down effect, weakening rock strength and abrasive property, prolonging bit life and enhancing bottom hole cleaning efficiency. The field test of improving drilling rate through.gas drilling in Qilibei 101 well showed that gas drilling could improve drilling rate from 1.7 times to 13.3 times, reduce drilling tool failures and circulation loss efficiently, and shorten construction cycle. Also, it is important for safe and successful drilling to carry out the analysis of well stability, formation water production and formation gas production and mating corresponding designs of well structure and drilling methods before drilling.