Gas drilling technologies play an increasingly important role in oil and gas exploitation. The modern gas drilling method minimizes reservoir damage and increases the efficiency of oil and gas exploration. The practical use and the development of the gas drilling technology are limited by the ineffectiveness of migration and control of the cuttings bed, which is unavoidable in horizontal sections during gas drilling. In this paper, the author applies the chemical initiation theory to study the initiation of the cuttings bed migration in a horizontal well in the process of gas drilling. Then, the author deducts the formula to calculate the cuttings bed initial velocity by considering characteristics of the cuttings in a horizontal well during gas drilling. The calculation results show that the initial velocity gradually increases with an increase in the size of cuttings, decrease in the cuttings sphericity, and increase in the degree of exposure in the cuttings window. The results are coherent with the field engineering data. The study can also provide a useful reference for the cuttings bed control in gas drilling of horizontal wells.

天然气钻井技术在油气开采中发挥着越来越重要的作用。现代天然气钻探方法最大限度地减少了对储层的破坏并提高了油气勘探的效率。气体钻井技术的实际应用和发展受到岩屑层运移控制不力的限制，这在气体钻井水平段是不可避免的。本文运用化学起爆理论研究了天然气钻井过程中水平井岩屑层运移的起爆过程。然后，结合气体钻井过程中水平井岩屑的特性，推导出岩屑床初速度的计算公式。计算结果表明，随着岩屑粒径的增大、岩屑球形度的减小、岩屑窗内暴露程度的增大，初速逐渐增大。结果与现场工程数据一致。该研究还可以为水平井气钻岩屑床控制提供有益的参考。