In many cases, the cleat system of undisturbed coals will be water filled and subjected to a hydrostatic head that exceeds the desorption pressure of gas occupying pores in the coal matrix. Therefore, water must be removed to lower the hydrostatic head below the gas desorption pressure to initiate coal seam gas (CSG) production. This is achieved by incorporating some form of submersible pump in the CSG well completion design.

Qteq’s Q-Fi® EMT PumpTraq system is a breakthrough wireless downhole technology for monitoring the water level above the pump.

The system employs electromagnetic telemetry (EMT) to transmit pump intake pressures through the surrounding overburden. The EM signal is detected at surface using one or more ground antenna, connected to an EM6 Surface Receiver Card. This card decodes the EM signal and outputs extracted pressure data as either a 4-20 mA signal or via a Modbus interface. This data is used to safeguard against the pump-off condition, which can cause rapid failure of submersible pumps, resulting in frequent, costly CSG well workovers.

The data is also used to prevent rapid well pumpdown during pump start-up operations, which can induce solids production. Using Q-Fi EMT PumpTraq to maintain the water level a minimum safe distance above the pump inlet also enables CSG operators to accelerate dewatering timeframes.

Q-Fi EMT PumpTraq has been custom-designed for CSG environments, and employs the same pressure sensor technology incorporated in Qteq’s field-proven digital ResTraq pressure gauge technology.

The signals output by the EM6 Surface Receiver Card can either be interfaced with the CSG operators’ infield networked data communications ecosystem or connected directly to a third-party pump controller.

Very extensive best practices have also been developed to ensure reliable installation and long-term performance of Q-Fi EMT PumpTraq systems.

Applications

• Optimise CSG dewatering strategies

• Prevent pump-off condition

• Prevent rapid pumpdown

• Monitor pressure transients during planned and unplanned shutdowns