Impact of tapered drill string assembly on well deviation during gas drilling

Gas drilling has been widely used due to its advantages of effective formation protection, lost circulation prevention, and high penetration rate. However in the actual gas drilling process, well deviation control difficulty has restricted the development of the technology. To study the effect of tapered drillstring assembly on gas drilling well deviation, based on the stress analysis of tapered drillstring assembly in gas drilling, the finite element mechanics model during the gas drilling operation was established, and its correctness was verified through theoretical calculations. Combined with actual drilling data of a gas well in Western Sichuan, the deviation control effect was researched about tapered drillstring assembly, and the influencing factors of well deviation were analyzed, showing that its ability would change with inclination and drilling pressure, and tapered drillstring assembly with air hammer was better than that with cone bit in deviation prevention, which provided theoretical guidance for deviation control research and field operation of tapered drillstring assembly during gas drilling.