A Novel Intermittent Gas Lifting and Monitoring System Toward Liquid Unloading for Deviated Wells in Mature Gas Field

For liquid-loading gas wells, effective deliquification operation is needed but current liquid-lifting technology is not able to meet the requirements of high efficiency as well as low cost especially in large-deviated wells. This paper proposes a hybrid deliquification technology combining plunger lift, chemical foamer injection, and down-hole monitoring to unload liquid in deviated gas wells. The system comprised multipart plunger body, deployment-retrieving integrating assembly (DRIA) and operation canisters. By means of flexible plunger body, the system performs deliquification normally in deviated wellbore. The operation canisters are carried with plunger body through tubing onto the bottom of deviated section to operate in terms of four modes: long-term down-hole monitoring, foamer injection, mobile data acquisition, and wireless data exchange with the wellhead. The key components of DRIA and injection valve are made of improved disintegrating alloy with the rating temperature of 100 °C, compressive strength of 370 MPa, and disintegrating rate of 170.9 mg/(cm² h) characterized by lab test. Field trials were successfully performed in two liquid-loading tight gas wells, and the maximal deviated angle of the wells was 68 deg. It indicates that the new technology is a cost-effective way contributing to automatic production and management of mature gas wells in the remote area instead of traditional rigid plunger and wire-line logging.