A major operator in the Middle East has been producing gas from the same formation for approximately 20 years. Traditionally, hydraulic actuators have been used to control the wellhead gate valves in these gas wells. These actuators have been operated from a hydraulic control panel that is pneumatically powered, and the compressors used to generate the instrument air are electrically driven. The existing systems have not only been inefficient, as they required electricity to power the hydraulic actuators, but they were also very maintenance intensive.

When the decision was made to begin a 5-year drilling program to develop additional gas reserves, an important part of the project development process was the investigation of alternatives to existing wellsite equipment. A unique system in which the gate-valve actuators, the control panel with a PLC as well as the pressure pilots, fusible plugs and ESD switches were electrically controlled, was chosen for testing. The system also incorporates a battery back up to maintain operation in the event of a power failure.

This paper will discuss the system and the testing program developed to assess its capabilities as well as the testing that was required to comply with other industry mandated testing. The paper will also delve into other ongoing projects using this technology and highlight the superiority of an electric system over more conventional hydraulic or pneumatic systems. For the project discussed in this paper, an existing well was converted to the all electric system, and a rigorous one year testing program was carried out by the operator. In addition to normal exposure to the elements and routine opening and closing of the well to meet production demands,

the test also included over 300 additional open and close cycles on each of the three electric actuators on the tree.

The operator estimates capital cost savings for the all electric system in excess of $200,000 per well over the present pneumatic/hydraulic systems. Additional savings would also be generated in the future from the manpower reductions planned when the system was fully proven. Finally, a reduction in maintenance would also impact operational costs.

In a recent analysis of the system capabilities to date, the operator specifically noted the following benefits:

  • The operators were able to handle their duties much more easily since the system is all push button.

  • The self-diagnostic features built into the panel allow quick troubleshooting of the system rather than requiring assessment of problems through trial and error.

  • The maintenance record to date has shown that minimal maintenance has been required.

The results of this project have also shown that other potential applications such as unmanned platforms and pipelines could benefit from this all-electric system.

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