Downhole problems are encountered in block Baka of Tuha oil field, such as wellbore instability, long operation time and low ROP. Based on the analysis of those downhole problems, an amino polyalcohols drilling fluid system is developed, and it is used in well Ke21-H1 with the drilling section of 2,000 m to 3,527 m. The application shows that 64 coal beds of 136 m and 49 clay stone formations of 49 m are drilled out safely and under coal bed formation of 420 m is directionally drilled to 3,947.5 m successfully.%吐哈油田巴喀区块因煤层发育,钻井过程中井壁失稳严重,井下复杂与事故频发,导致钻井周期长、机械钻速低.针对以上问题,分析了井下复杂发生的原因,优选了强抑制剂和封堵防塌剂,形成了胺基聚醇钻井液并在柯21-平1井2 000～3 527m井段进行了现场试验.应用结果表明,应用井段无复杂,顺利钻穿煤层64套共136m和碳质泥岩30套共49 m,并在煤下地层定向钻进420m,钻至中途完钻井深3 947.5 m,矿场应用效果良好.
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