Research and Application of Plunger Gas Lift Technology in the Fuling Shale Gas Field

Plunger gas lift technology is often used for drainage of water and gas recovery in gas wells. However, the conventional short plunger cannot solve some problems in shale gas well in Fuling Shale Gas Field, such as the large master valve on wellhead and downhole variable-diameter pipe string, therefore, an elastic block variable-diameter combined plunger was developed. The plunger adopts the design of elastic block and lengthening, which not only ensures the passage of the plunger, but also effectively reduced the leakage rate of the plunger. The temperature and pressure instruments are installed in the plunger to monitor the downhole pressure and the running state of the plunger, so as to provide the basis for adjusting the operating system of the plunger. According to the production characteristics of shale gas wells at different stages, the intervention time and operation system of plunger gas lift are optimized. Plunger lift technology has been applied in 34 wells in Fuling Shale Gas Field, with average daily gas production of a single well increased by 0.95×10⁴ m³, realizing shale gas production continuously and stably. The plunger gas lift technology provides a new technical way for the efficient development of Fuling Shale Gas Field, and has a function of guiding the development in other shale gas fields.