The main layer of Changbei Block is exploited by extended reach horizontal wells. The initial production of the gas well is high and the size of the completion string is large, yet the well bore has fluid accumulation in the middle and late development period, and the production is abnormal. Because the tubing packer is not released and there is no circulation channel, it is difficult to implement foam, gas lift and other deliquification methods. To solve this issue, a method of running velocity string of smaller size into the original string as the production string is adopted. The research on the running time, size optimization, running depth and hanging mode of velocity string was carried out. By the end of 2021,7 VS wells have been applied on site. With rational process design, the liquid carrying capacity of the gas well is significantly enhanced and the production is stable. The long-term stable production effect has been achieved, which has laid a good foundation for the continuous promotion and application of the block, and also provides reference for the deliquification and gas production of similar gas wells in other gas fields.