长庆气田水平井PDC钻头防泥包技术

为实现长庆气田水平井钻井提速的目的，在斜井段中试验了PDC钻头，但均不同程度地发生了钻头泥包的问题。经过广泛的调研分析，找到了导致PDC钻头泥包的主要因素--钻井液问题，另外还有地层、钻井参数、PDC钻头流场设计等影响因素。为此，从强化钻井液抑制性出发，研制出了双钾盐聚合物钻井液体系并在现场应用获得成功，较好地解决了PDC钻头泥包问题。其中GP12 6井实现了斜导眼水平井单只PDC钻头穿越5套地层，平均机械钻速达11.25 m/h，起下钻、电测和下套管等作业均安全顺利完成。

Anti-bit bailing for PDC bits of horizontal wells in Changqing gas field

During the construction of horizontal wells in the Changqing gas field, the bit balling of PDC in the lower slope section became the main technical bottlenecks that restricted the improvement of ROP. It was found through the analysis and research of the use of PDC bits in recent years that drilling fluid was the most important factor which caused bit balling, and surely formation properties, drilling parameters, and the PDC bit design were also listed in the main factors. The solution method for bit balling is to improve the inhibitive capacity of drilling fluid, and then the bi-potassium salts based polymer drill-ing fluid was developed and successfully applied on well sites, and the bit balling of PDC bits has been basically resolved since then, and it was in the well GP12-6 that only one PDC bit drilled through five formations in guider section for anti-bit bailing, with the average ROP being 11.25 m/h and without any sticking problems during trips, logging, and casing running.