Abstract

Automatic and remote operated drilling chokes have been in the petroleum industry for a very long time. Managed Pressure Drilling (MPD) operations have been using these chokes since ±2006 and prior to that Underbalanced Drilling (UBD) operation have been using them for decades. The main control or actuation of these drilling chokes is achieved by adapting standard API-16C hydraulic or electric actuated worm gear drive actuators. These methods of actuation however have limitations related to ‘Response Time’ and ‘Equipment Failure', making these actuators less desirable for MPD applications.

An advanced method of actuation using ‘Electro Servo Actuator’ is presented as an alternative to alleviate these challenges. These electro servo actuators are designed from the outset considering the requirements of MPD Choke operations, and are optimized to provide precise control of chokes along with a reduction in the number of potential failure points.

During extensive laboratory testing, required as a quality standard for our MPD choke's factory acceptance program, these actuators provided very accurate and responsive pressure control to quick changes in pressure demands based on variations in both set point and flow. Furthermore, the initial field testing of the actuator in the MPD field operations demonstrated the same precise and accurate pressure control tracking, along with better performance at ‘lower flowrates’ when compared to worm gear driven chokes. Full-scale field application on over 20 different projects across North America, including a wide range of severe weather conditions, exceeded the expectations and results from initial testing.

In conclusion, the use of this new ‘Electro Servo Actuator’ technology greatly increases the precise control of drilling chokes very crucial for all MPD applications. This technology reduces the potential failure points in the actuators. It enhances the uptime of the actuator and its life cycle, thereby minimizing the need for routine maintenance. Its smaller size and design enables development of more compact MPD chokes and equipment.

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