Practice of Closed Suction Drainage Gas Production Technology in Water Flooded Gas Wells

In order to realize the potential tapping and re-production of flooded gas wells at low cost, exploratory research on closed suction drainage and gas recovery technology has been carried out based on conventional suction drainage techniques. Firstly, starting from the technical principle of suction drainage and gas production, this paper deeply analyzes the technical difficulties of tapping the potential and resuming production in flooded gas wells, such as stuck upward flow induced by the suction plunge and well control problems. And it introduces in sequence the structural optimization design of the suction plunger to prevent upward migration during induced flow, the theoretical analysis of the critical conditions for induced flow, the optimized design of the wellhead blowout preventer, as well as the combined technology of suction and self-generated gas. Through the exploratory application in dozens of flooded wells on site, the risk of the suction plunger’s upward migration and jamming has been successfully overcome. The operational success rate is 97%, the production increase efficiency is over 80%, and the average daily production increase per well is 6,600 m3. This effectively forms the closed suction drainage and gas recovery technology in flooded gas wells. However, based on practical issues encountered in the field, such as operational difficulties due to downhole obstructions, elevated pressure in the production pipeline network, and the inability of gas wells to maintain continuous production, it is recommended that well selection be optimized on one hand, and on the other hand, consideration should be given to equipping the wellhead with an automatic suction device to address the challenges of non-continuous production in flooded gas wells.