Automated Control of Annular Backpressure in Two High‑GOR ESP Wells Increased Their Production by 14%

Published: 02/26/2022

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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.

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The AgoraGateway device enabled remote monitoring of well performance, while the self-regulating Modum Gas system maintained annulus pressure within set limits.
Graph showing lower ESP intake and casinghead pressures and higher production with Modum Gas system.
Following installation of the Modum Gas system skid on one well, casinghead gauge pressure dropped from 190 psi to 100 psi, while ESP intake gauge pressure stabilized and fell from approximately 270±90 psi to 160±5 psi. Production increased 12% from 290 bbl/d to 325 bbl/d.
Graph showing lower ESP intake and casinghead pressures and higher production with Modum Gas system.

Operator enhanced recovery and production efficiency

Using the Modum Gas system reduced monthly trips for manual intervention in the two wells by 97% (from 58 to 2), while average production increased by 14%. As the trial progressed, ESP efficiency improved from 21% to 33% and power consumption fell 11%. Pleased with the results, the operator has decided to implement this wellsite automation solution in 10 additional wells.

South America, Onshore

Modum Gas gas metering control system boosted productivity, minimized trips to the wellsite, decreased costs and HSE risk, and improved ESP performance on two land wells.

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