Management of annulus pressure required frequent manual interventions

Annular gas handling is a common operational issue in high-GOR wells equipped with ESPs. Gas in the production stream is separated downhole before entering the ESP and accumulates in the well annulus. The resulting backpressure on the reservoir reduces production and creates variations at the ESP intake, negatively impacting pump performance and run life. An operator in South America was dispatching technicians to manually release pressure by adjusting the position of an annular ball valve multiple times per month. In addition to consuming significant time and resources, the lack of a continuous control capability resulted in suboptimal production rates and increased HSE risk.

Autonomous gas metering and control provided a cost-efficient solution

Schlumberger proposed deploying its Modum Gas gas metering control system downstream of the annulus to measure and maintain targeted pressures. The system requires no modification to the flowline and integrates sensors with a needle valve assembly, flow controller, stepper motor, and LCD. The sensors measure temperature and inlet, outlet, and differential pressures; the flow controller uses this data and the stepper motor position to calculate the flow rate in real time. If the pressure falls outside a target range, modulation of the needle valve returns it to an acceptable value. Flow rate data helps the operator plan proper disposal of the annulus gas.

The flow controller was connected to an AgoraGateway ruggedized edge computing device to enable remote monitoring; an existing SCADA system can be used instead if preferred. The required annulus pressure limits were set remotely, and the smart system with its closed-loop capabilities provided the continuous measurement, control, and self-regulation required to maintain the set point under changing well conditions. Using the AgoraGateway device’s cloud-based infrastructure, the team was able to view historical and current well performance to ensure accurate control and maintenance of desired pressures. A Vx Spectra surface multiphase flowmeter was used to periodically measure well production and confirm the improvement achieved.