An electric submersible pump (ESP) is a powerful artificial lift pump that uses a motor-driven centrifugal pump to extract fluids and other substances from wells. It is a type of water pump that operates by submerging the pump in a body of liquid and utilizing an electric motor for propulsion. The motor is securely enclosed in a watertight casing, allowing the pump to be placed in deep wells, reservoirs, or tanks.
ESP finds extensive usage in pumping water or oil from oil wells, water wells, and various industrial or agricultural settings. It is a versatile multistage centrifugal pump that offers engineers a wide range of flow rates and head pressures. Moreover, its exceptional energy efficiency makes it a preferred choice for diverse applications.
By converting the kinetic energy of the liquid into work to boost pressure, electrical submersible pumps have gained popularity due to their remarkable performance. These pumps are particularly favored in agricultural settings, contributing to their increasing adoption on farms.
Explore this comprehensive guide to electric submersible pumps and gain valuable insights into their working principles, component functionalities, installation procedures, maintenance requirements, and a plethora of applications. Discover how ESP can cater to your submersible pumping needs effectively.
A Historical Journey of the Electrical Submersible Pump
The roots of the electrical submersible pump (ESP) can be traced back to 1916 when the visionary Russian inventor, Armais Arutunoff, pioneered its development. After relocating to the United States in 1923, Arutunoff founded the Russian Electrical Dynamo of Arutunoff (REDA) company. His innovative creation caught the attention of potential investors in the USA.
Initially, Arutunoff approached Westinghouse with his concept, but the engineers at the company deemed it impossible due to electronic principles. However, in 1927, Arutunoff found a breakthrough when he provided a solution to Phillips Petroleum’s challenge. The company was in search of a high-volume production method to enhance the profitability of their high water-cut wells.
As time progressed, REDA Pump Company flourished and became the world’s largest manufacturer of electrical submersible pumps in the late 20th century. Until 1969, the company operated independently, without any affiliation to other businesses. However, in 1998, REDA Pump Company became a subsidiary of Schlumberger when the latter acquired CAMCO.
This captivating historical overview showcases the remarkable journey of the electrical submersible pump, highlighting the ingenuity of Armais Arutunoff and the subsequent growth of REDA Pump Company under Schlumberger’s umbrella.
The Electrical Submersible Pump (ESP) System Unveiled
The ESP system comprises a series of centrifugal pumps, powered by a multistage centrifugal pump, working in harmony to extract fluids from the well and bring them to the surface. Let’s delve into the workings of this system:
Starting Up the ESP System
To initiate the electrical submersible pump, a soft starter or variable speed drive (VSD) can be employed. This aids in kickstarting the pump and facilitating the cleaning of the well before full operation. By allowing a low flow rate initially, the well can be thoroughly cleaned, and production can be gradually increased as the well undergoes rehabilitation.
The Working Principle of ESP
At the core of the electrical submersible pump lies a vertically oriented centrifugal pump installed within a borehole. This pump employs impellers to enhance the fluid’s velocity. The resulting energy generated by the impellers is then converted into pressure energy by the diffuser.
Furthermore, the ESP system is typically composed of multiple stages, each equipped with an impeller and a diffuser. As the liquid passes through the impeller of the first stage, its radial outward velocity intensifies, resulting in centrifugal force. This force, along with the impeller’s sharp edges, transforms the fluid’s kinetic energy into pressure as it reaches the diffuser.
By comprehending the intricate workings of the ESP system, one can better appreciate its role in efficiently pumping fluids from the well, ensuring optimized performance and reliable operation.
Components of Electrical Submersible Pump
The ESP system consists of several vital components, each playing a crucial role in its operation. These include:
Centrifugal Pump:
At the heart of the system is the centrifugal pump, responsible for providing additional lift and transferring pressure to ensure the desired fluid flow from the wellbore. It accomplishes this by utilizing centrifugal force to impart kinetic energy to the fluid and subsequently converting it into potential energy through pressure. Centrifugal pumps come in various diameters to suit common casing sizes.
Electric Motor
The electric motor drives the ESP, generating the necessary head pressure to lift the liquid to the surface. The motor’s size and horsepower determine the number of stages required. The motor’s temperature during operation is managed by drawing fluid into the pump for cooling. The motor’s size also influences the overall length and diameter of the ESP system’s bottom-hole equipment.
Power Cable
The ESP motor is supplied with surface power through the power cable. This cable is securely attached to the production tubing, running from the wellhead to the ESP unit. It is designed to withstand harsh conditions and is not meant to bear any weight. The power cable is built with three-phase electrical wire and must be resistant to mechanical and electrical stress.
Controllers
Controllers serve as the surface interface for the ESP system, providing power to the motor and safeguarding the downhole components from environmental hazards. Variable-speed controllers or soft-start controllers are used, depending on the specific requirements. Variable-speed drives (VSDs) can be operated mechanically or electronically, while soft-start controllers gradually bring the pump motor up to its optimal operating speed in a multistage centrifugal pump.
Sensor
A bottom-hole sensor is often installed to provide real-time information about system parameters such as pump intake and output pressures, temperatures, and vibrations. This enables operators to maximize efficiency by monitoring performance closely. If readings fall outside the preset range, the sensor sends alarms to the operator, allowing for remote or automatic adjustments by the surface controller.
Understanding the functionality and significance of these components is essential for comprehending the intricate workings of an ESP system, ensuring effective pumping operations in diverse applications.
Installation of an Electrical Submersible Pump (ESP)
Installing an electrical submersible pump (ESP) involves several crucial steps to ensure a proper and secure setup. Here’s a detailed guide on ESP installation:
- Fueling the Engine: Position the motor vertically on its base within the pump. Double-check and tighten any bolts as needed. Add clean, cold water to hydrate the motor, rock it back and forth to remove trapped air, and screw the plugs securely. Verify there are no water leaks and address any issues accordingly.
- Waterproofing the Wires: Make a watertight connection between the free end of the submersible motor cable and the supply cable from the control panel. This ensures the connection remains protected from water ingress.
- Valves Check: Ensure the well valves are closed when the ESP is not in use to prevent water from leaking back into the well.
- Motor’s Rotational Direction: After connecting the supply cable and motor cable securely, confirm the submersible motor’s rotational direction. Follow the markings on the cable box, typically indicating an anticlockwise rotation. Plug the motor into the control box and briefly switch it on to validate the sand guard’s rotational axis, which should result in water flowing over it. If the markings on the cable box are incorrect, reverse the direction by switching any two lead wires in the control panel.
- Check for Rotational and Tactical Freedoms: Ensure that both the pump and motor shaft can rotate freely and move up and down without obstruction.
- Connecting the Pump to the Submerged Motor: Assemble the tripod and chain link, detach the submersible pump’s cable guard and filter, and maintain a vertical position for the ESP using the submersible motor. Attach the connection to the drive shaft or pump shaft using a grub screw. Apply threading compound and screw the delivery pipe into the delivery casing. Check for any play in the assembled shaft. Connect the pump to the motor shaft, lower it until it aligns with the inlet bracket, suspend the pump from the chain block, and secure the supply hose with a clamp.
- Electrical System Installation: Connect the submersible motor’s control panel to the power source using a single cable. Ensure proper grounding to protect the underwater motor. Maintain a watertight connection at the cable’s end. Trim any excess cable length and secure it to the engine’s starter terminals. Consider appropriate wire sizing for low-voltage operation.
- Secure Pump Lowering: Attach a T-handle end of a poly rope to the pump’s lug and secure the end of the safety rope to the inner well cap on both ends. Verify that the outer well cover is firmly fastened to the pump. Complete the installation by connecting the power wires.
By following these installation steps meticulously, the electrical submersible pump can be installed safely and efficiently, ready to provide reliable pumping operations.
Maintenance of Electrical Submersible Pump
To ensure smooth operations and address any potential issues, specific guidelines should be followed for operating and maintaining electrical submersible pumps (ESP). After extracting the ESP from the well, its components can be disassembled and analyzed, regardless of salvageability. Here are some maintenance guidelines for a multistage centrifugal pump:
Check for Overheating:
Regularly inspect the pump for signs of overheating. Inadequate water for cooling or pump malfunctions can cause overheating.
Lubricate the Pump:
Ensure proper lubrication of the pump for smooth operation.
Inspect the Motor:
Frequently examine the motor of the pump. Check for tight connections and ensure the starter is not overheating.
Replace Hoses and Fix Leaks:
Seals and hoses in the ESP are prone to wear and strain. Regular inspection and timely replacement are essential to prevent significant damage.
Applications of Electrical Submersible Pumps (ESP)
ESP offers several advantages and finds diverse applications in various industries, including:
- Powering Agricultural and Industrial Irrigation Systems: ESP plays a vital role in providing power for agricultural and industrial irrigation systems, ensuring efficient water distribution and enhancing crop productivity.
- Pumping Out Flooded Areas at Construction Sites: ESP is utilized to pump out water from flooded construction sites, helping to maintain a dry and safe working environment.
- Sewage and Sludge Management: These pumps are commonly employed in sewage and sludge management systems. Pressure and level sensors are installed beneath sewage levels to regulate and control the system effectively.
- Transportation of Crude Oil: Multistage centrifugal pumps equipped with ESP technology are used to transport crude oil from deep underground wells to surface processing and storage tanks. They provide reliable and efficient oil transportation.
- Aboveground Storage Tanks: ESP plays a crucial role in transferring oil from deep underground wells to aboveground storage tanks, ensuring efficient storage and distribution.
- Dependable Submersible Pump Cables: Submersible pump cables must be durable and resistant to harsh environmental conditions. They are designed to withstand challenging environments, making them suitable for use in both fresh and saline water applications.
ESP plays a crucial role in agricultural and industrial irrigation systems, controlling water levels in flood-prone areas, sewage management, and transporting crude oil. These pumps are designed to withstand harsh environments, and the power cables used in multistage centrifugal pumps are suitable for both fresh and saline water applications.
Advantages of ESP
Electrical submersible pumps (ESP) offer numerous advantages that make them a preferred choice for various applications. Here are some key benefits:
- Accommodates Different Well Configurations: ESP systems can be installed in wells with varying configurations, including those with horizontal sections and maximum inclinations. This flexibility allows for efficient pumping operations in a wide range of well geometries.
- Increased Output Efficiency: The multistage centrifugal pump design of ESP enables higher output even in scenarios where water cuts are present due to pressure checks and secondary recovery techniques. This ensures optimal productivity despite changing well conditions.
- Low Noise and Environmental Impact: ESP systems are known for their low noise levels and minimal environmental impact. This makes them suitable for use in environmentally sensitive areas, including offshore locations, without causing significant disruption or disturbance.
- Resistance to Challenging Well Environments: Artificial lift pumps, such as ESP, are capable of withstanding challenging well conditions. They can handle high gas-oil ratio (GOR) fluids, high temperatures, and corrosive acid gases commonly encountered in certain well settings, ensuring reliable and efficient operation.
- Versatile Capacity for Varying Fluid Characteristics: ESP systems have the capability to handle large volumes of fluids, allowing for adaptability to changing fluid characteristics and flow rates over the operational lifetime of the well. This flexibility ensures efficient pumping performance in different operating conditions.
The advantages of electrical submersible pumps make them a valuable solution for a wide range of industries, providing efficient and reliable pumping operations while accommodating diverse well configurations and challenging well environments.
Disadvantages of ESP
While Electrical submersible pumps offer several advantages, they also come with certain limitations. Here are some disadvantages to consider:
- Limitations with Well Curvature: The curvature of the well can impose restrictions on the deployment and landing of multistage centrifugal pumps. The pump’s usability may be limited in wells with complex geometries or significant curvature.
- Sensitivity to Particles in Production: Multistage centrifugal pumps are sensitive to the presence of particles in the production fluid. Even trace amounts of sand and solids can have a significant impact on the system’s performance. It is crucial to minimize particle content to avoid potential clogging or damage.
- Challenges with Motor Seal Erosion: When the motor’s seals erode over time, water can seep inside and cause the motor to stop working. Repairing the pump can be challenging due to its construction, requiring careful attention and expertise to address seal erosion effectively.
- Equipment Size Limitations: Multistage centrifugal pumps designed for moderate to high output rates often require casings with large outside diameters, exceeding 4.5 inches. This can pose challenges in applications where space constraints or specific installation requirements exist.
- Considerations for Dogleg Severity: Manufacturers must account for dogleg severity when calculating the tension and deflection of pump components. Dogleg severity refers to the degree of curvature or deviation from a straight path in the well. Proper consideration of this factor is crucial to ensure correct assembly and functionality of the pump.
It is important to weigh these disadvantages against the specific application and well conditions when considering the use of multistage centrifugal pumps. Proper maintenance, monitoring, and addressing these challenges can help mitigate their impact and maximize the pump’s performance.
Conclusion
When it comes to selecting pumping systems, engineers and operators are increasingly recognizing the multitude of benefits offered by multistage centrifugal pumps in both downhole and surface applications. These pumps provide optimal performance and efficiency in various scenarios.
To meet evolving industry demands, the electrical submersible pump (ESP) sector is actively working on developing more durable pumps that can effectively handle high solids flow conditions. The aim is to make ESP systems more practical and reliable, even in challenging environments with significant particle presence.
Ongoing research and development efforts are primarily focused on enhancing the dependability of individual components and integrated systems within artificial lift pumps. By improving the reliability and longevity of these components, the overall lifespan of ESP systems can be significantly extended.
Furthermore, advancements are being made in the development of advanced algorithms for operating surveillance and control of ESP systems. These improved algorithms enable better monitoring and management of pump performance, ensuring efficient operation and timely detection of any potential issues.
As the industry continues to evolve, the continuous development and innovation in multistage centrifugal pumps contribute to their growing reputation as the optimum choice for various pumping applications. With ongoing improvements in durability, reliability, and control systems, multistage centrifugal pumps are poised to meet the evolving needs of the industry effectively.