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This Jidong Oilfield underground gas storage project supports seasonal gas regulation for the Beijing–Tianjin–Hebei region by injecting natural gas into underground storage in summer and producing gas during winter demand peaks.
XGTHERMAL supplied two BDRG vertical explosion-proof electric heater packages for the early injection and production pilot. The heaters are installed upstream of the wellhead choke valve and heat the produced gas, crude oil, and water mixture before pressure reduction, helping prevent hydrate formation, wax deposition, freeze blockage, and unstable downstream metering during winter gas withdrawal.
The package was designed around high-pressure wellhead flow, coastal salt-spray exposure, and unattended operation requirements.
The wellhead heating package had to protect a high-pressure multiphase gas-storage stream before choke-valve pressure reduction.
XGTHERMAL used a vertical indirect phase-change heater package with high-pressure coil design, stepless power control, and layered safety interlocks.
During gas withdrawal, high-pressure gas from the underground reservoir must be reduced to gathering pressure through a choke valve. Because the Joule–Thomson effect can sharply lower gas temperature during throttling, untreated flow can form hydrates downstream of the valve. The heater raises the wellhead stream temperature before pressure reduction so that the post-choke medium remains above hydrate formation conditions.
The application is more complex than dry-gas heating. The stream includes natural gas, crude oil, and produced water. Wax-bearing crude oil can deposit at low temperature, while water and acid gases can increase corrosion risk. Heating the combined stream improves freeze protection, wax control, corrosion mitigation, and downstream metering stability.
The heater uses an indirect negative-pressure phase-change heat-transfer system. Electric elements heat an intermediate working fluid; vapor rises, condenses on the outside of the internal coil, releases heat, and returns by gravity. This Gravity Heat Pipe cycle provides uniform heat distribution without exposing the electric heating elements directly to the high-pressure oil-gas-water stream.
The process medium flows through a pressure-rated helical coil. The coil extends the flow path, increases heat-transfer residence time, strengthens turbulence, and provides additional heat-transfer margin. The pressure-retaining parts, high-pressure flange connection, corrosion allowance, and non-destructive inspection strategy were selected around high-pressure gas-storage service requirements.
The control system is built around an industrial PLC platform, a local explosion-proof HMI, and SCR thyristor stepless power control. In normal production, the heater can regulate output smoothly with PID temperature control, avoiding the temperature swings and electrical impact associated with simple contactor step control.
The package supports local and remote operation modes. Protective logic includes outlet overtemperature, shell overtemperature, outlet overpressure, no-flow shutdown, overcurrent, leakage, undervoltage, phase-loss, explosion-proof opening interlock, and remote ESD. Status, fault, temperature, pressure, and remote-control signals are integrated through standard industrial communication for unattended well-site operation.
For Jidong Oilfield, the heaters help keep the gas storage project available during winter gas withdrawal by reducing hydrate, wax, and freeze-blockage risk before the critical throttling point. The vertical skid-mounted configuration allows factory integration, field installation by pipe and cable connection, and simplified maintenance access through a platform and ladder.
The project also demonstrates XGTHERMAL's capability in underground gas storage heating, where high pressure, multiphase flow, coastal corrosion, hazardous-area classification, and remote operation must be solved as one package. The same engineering logic can support future gas-storage, wellhead heating, and oil-gas-water multiphase flow-assurance projects.
A directly relevant product family for phase-change explosion-proof electric heating and wellhead flow assurance.
