Development of Wireless Monitoring Plunger and Its Application in Process Effectiveness Diagnosis

Plunger gas lift, as a cost-effective drainage and gas-production method, has been applied in over 220 shale gas wells in southern Sichuan province with a series of positive results. Shale gas wells usually experience rapid production and pressure decline, and the ineffectiveness of the operation systems. Due to these characters above, relying on the surface parameters alone could hardly meet the needs of timely diagnosis and adjustment of the operation system. To address this, researchers developed a wireless monitoring plunger by integrating multiple sensors and communication chips using microelectronic technology and short-range wireless communication technology. This tool measures down-hole temperature, pressure, plunger position, and liquid level during periodic operations. It collects real-time down-hole data and transmits them at well-heads, enabling continuous monitoring of plunger operation parameters. The tool achieved breakthrough of positioning function through the use of electromagnetic induction principles, which allows the collection and the analysis of critical parameters including instantaneous plunger velocity, angle, well-bore liquid level, and well-bore temperature-pressure profiles. This innovation established a preliminary diagnostic method for the plunger operation status. Field tests were successfully conducted in seven shale gas wells in southern Sichuan province including well Z202 and well CLH3–6. The tool provided accurate data that identified abnormal conditions such as excessive plunger speed, mid-stroke stoppages, and absent liquid levels above limiters. These findings offer targeted solutions and provide technical support for improving drainage efficiency.