Electric actuation: a gamechanger for upstream processes
The electrification of upstream oil and gas processes offers the opportunity to reduce emissions of greenhouse gases while improving efficiency.
The International Energy Agency has warned that the oil and gas industry needs to reduce its emissions by 60% by 2030 to align itself with a global rise in temperatures of just 1.5°C.1 Fortunately, it believes the sector is well placed to scale up some crucial technologies for the clean energy transition.
Currently, methane is released at wells when gas is vented directly to the air, when flaring to burn off the gas is incomplete, or through leaks. But these emissions can be reduced by more than 75%2 with simple solutions such as leak detection, repair programs, and upgrading leaky equipment to include electric actuators.
Methane is also a valuable resource that could be sold as natural gas, converted to fuels, used for chemical production or stored underground. More than 260 billion cubic metres (bcm) of natural gas is wasted through flaring and methane leaks globally. With the right policies and implementation, around 200 bcm of additional gas could be brought to market.
Improving on traditional valve technologies
In upstream oil and gas production, control valves have historically been operated by pneumatic diaphragm actuators that use the well-stream gas as their motive power, releasing methane every time the valve is stroked. To reduce these emissions some operators have now replaced well-stream gas with air compressors, but these require a large amount of energy.
Electric actuators do not vent, and many provide one-piece actuation solutions, which reduces the risk of failure compared to the typical pneumatic solution involving multiple pieces of equipment — where each of these parts can suffer from air quality fluctuations, temperature variations and other environmental factors.
Electric actuators are less susceptible to these influences and more energy efficient, since they only consume electricity when in operation — making them suitable for in-field solar powered infrastructure in remote locations. They provide the required torques and thrusts while operating at the necessary speeds for choke and process control valves. In addition, they offer the highest resolution output and modulating duty for accurate pressure and flow rate control.
Improving energy efficiency and reducing costs
Electric actuators are suitable for upstream applications such as gas metering, production trees, processing, saltwater disposal and gas lift systems. Many come with fail-to-position options that automatically return valves to a predetermined position in case of power loss or emergencies, enhancing safety and preventing potential damage to equipment.
In-field interventions can also be rapid and simple, whether carried out remotely, in control rooms or by physical interaction with the actuator.
Using self-contained electric actuators instead of pneumatic solutions not only helps to reduce methane emissions but results in cost savings and increased operational efficiency. Electric actuators also feature user-friendly interfaces and software tools that simplify the commissioning process, making them a perfect solution for valve applications in the oil and gas industry.
Data logging and asset management
Intelligent actuators are designed to not only provide reliable and repeatable performance in the challenging environments of remote oil and gas wells — they can also monitor temperature, torque and voltage to ensure the unit’s integrity and operating performance, resulting in a longer product lifespan.
Intelligent electric actuators with data logging can capture a large amount of data, such as the number of valve operations, alarms, valve torque profiles and unauthorised operation attempts. Monitoring valve behaviour enables them to identify patterns indicative of impending malfunctions — a predictive capability that allows maintenance teams to address issues before they cause disruptions, saving time and money on repairs, and helping to prevent unplanned downtime.
Intelligent valve actuators can also adjust valve positions based on real-time operational conditions. This helps to minimise energy consumption and reduce emissions, while also helping to prevent leaks and other safety hazards.
Replacing pneumatic actuators
A huge amount of oil field infrastructure still includes isolation valves, choke valves and process control valves operated by well-stream-gas-driven pneumatic diaphragm actuators. As mentioned, these valves constantly release methane but another challenge is ensuring the gas is dry enough to prevent system failure from condensation.
The right electric flow technology can significantly increase efficiency and uptime, while reducing emissions in line with the aspiration of being among the industry’s lowest methane emitters. Every valve in an oil field can be replaced with electric actuators that result in no emissions.
Electric solutions can play an important role in controlling the flow throughout the oil and gas value chain and are critical in upstream applications. Valve actuators are used for all types of valve operation including metering, processing and isolation duties, while fail-safe flow control solutions are specified on safety-critical systems such as oil and gas storage tanks.
The benefits of electric actuators
The benefits are evident across upstream applications.
Production trees
The production tree (or Christmas tree) is an assembly of valves, spools and fittings that regulate the flow of oil or gas from a well.
In the event of overpressure, a fail-safe/shutdown valve installed at the upper wellbore known as a surface safety valve (SSV) is used to protect the production systems. A production choke valve also controls the flow of well fluids being produced and regulates the downstream pressure in the flowlines.
Electric actuators are suitable for advanced production choke valve actuation, with proportional control, high accuracy and low power consumption, while modular electro-hydraulic actuators combine the simplicity of electrical operation with the high torque/thrust and fail-safe fast-action capabilities of hydraulic high-pressure control needed for failsafe operation of the SSV valve.
Production processing
Electric control valve actuators are an advanced and energy-efficient solution to replace leaky and energy-inefficient pneumatic diaphragm actuators. They are suitable for dump valves and back-pressure control valves, commonly used in upstream production processing applications. Such actuators not only help achieve net-zero emissions with a solar-powered 24 VDC supply option but also help reduce overall lifecycle costs compared to the instrument air actuator alternative.
Gas metering and LACT skids
Natural gas production metering and lease automatic custody transfer (LACT) for oil production metering are two crucial aspects that connect upstream operations to midstream gathering infrastructure. The pipelines and valves used in midstream operations are usually larger and require higher torque/thrust ranges for valve actuation than those used in upstream production processing infrastructure.
Multiple flow control systems operate together on a custody transfer metering skid to ensure low measurement uncertainty and high metering accuracy. The flow control on metering skids must be highly accurate and reliable and always provide safe valve operation. To automate large control valves with high-pressure ratings, a high-output electric actuator can deliver increased linear thrust and stroke length.
Electric high-torque/thrust valve actuators can be utilised without the complexity and cost of a pneumatic supply, and are capable of high duty cycles suited to the requirements of LACT valve actuation.
Gas lift systems
When extracting oil from underground wells, a gas lift system is used to lift the fluids to the surface. This system works by injecting high-pressure gas into the well to reduce the density of the fluids and create a ‘scrubbing’ effect that lowers the pressure at the bottom of the well, allowing the fluids to flow more easily.
A reliable and adequate supply of high-quality lift gas is required for the gas lift system to work correctly. A control valve modulates the flow and pressure of the gas being injected into the well. Electric actuators are also suitable for this application, designed to operate continuously and precisely, making them ideal for continuous modulating applications like gas lift systems.
Saltwater disposal systems
Produced water is the largest liquid produced in the oil and gas industry. The water from the well can be 4–5 times the volume of produced gas or oil from the same well. This water is then transported to recycling tanks or saltwater disposal wells through an intricate gathering line network.
The entire system is fitted with several actuated valves that ensure the safe and efficient flow control of produced water. Most control valves in the constructed water infrastructure require a high degree of controllability to prevent water hammering.
Additionally, back-pressure control valves must operate with high-frequency modulation duty to ensure optimal performance of water injection pumps. Many electric actuators offer adjustable speed, including a slow mode for precise positioning, high accuracy, high-resolution micro-step movement, and flexible torque/thrust protection.
Conclusion
Intelligent, electric actuation is rapidly becoming a necessity for upstream oil and gas processes as the need to reduce harmful emissions and costs becomes more pressing. Electric actuators are emission-free and provide the necessary capabilities with low energy consumption suitable for remote solar-powered applications and the data logging and intelligence for modern asset management and predictive maintenance.
1. International Energy Agency 2023, ‘The Oil and Gas Industry in Net Zero Transitions’, World Energy Outlook 2023, <<https://www.iea.org/reports/the-oil-and-gas-industry-in-net-zero-transitions>>
2. International Energy Agency 2023, Global Methane Tracker 2023, <<https://www.iea.org/reports/global-methane-tracker-2023>>
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