Retrievable ESP Rotor Layout for Downhole Reliability
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Solution Overview
Problem
Artificial lift systems in wells often fail due to electrical system failures, leading to costly workover procedures and lost production, as these systems are exposed to hostile downhole environments and have integrated electrical components with rotating parts, reducing reliability and increasing maintenance costs.
Innovation Solution
The design of an electric submersible pump (ESP) with a stator chamber and rotor, where the stator remains in the well while the rotor is retrievable, featuring a cooling circuit and magnetic bearings to improve reliability and separate electrical components from the hostile environment, reducing the need for frequent workovers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If electrical components are integrated with rotating parts in artificial lift systems, then the system can function as a complete artificial lift unit, but the reliability decreases due to exposure to hostile downhole environments
Solution Approach 1:
The artificial lift system is divided into separate functional components: the electric motor with electrical components is separated from the pump assembly with rotating parts. The motor can be positioned in the wellhead or surface equipment, while only the pump rotor operates downhole. This segmentation isolates electrical components from the hostile downhole environment, thereby improving reliability.
Solution Approach 2:
The electrical components (motor, control electronics) are extracted from the downhole environment and positioned in the wellhead or surface equipment. Only the essential mechanical pump components remain downhole, eliminating the exposure of electrical components to harmful factors such as moisture, heat, and pressure, thus improving system reliability.
2Reliability
If workover procedures are performed for equipment maintenance, then equipment reliability can be restored, but lost production occurs during the shutdown period
Solution Approach 1:
The system incorporates self-diagnostic capabilities and condition monitoring that allow operators to detect potential failures before they occur. This proactive approach enables planned maintenance during non-critical periods rather than emergency workovers during production, minimizing lost production time while maintaining equipment reliability.
3Reliability
If workover procedures are performed for equipment maintenance, then equipment reliability can be restored, but maintenance costs increase
Solution Approach 1:
By segmenting the system into separable components (motor vs. pump), maintenance can be performed on individual modules rather than requiring complete system retrieval. This reduces workover complexity and cost while maintaining reliability, as only the faulty component needs to be replaced or serviced.
Solution Approach 2:
The system includes self-diagnostic and condition monitoring features that enable early detection of potential failures. This allows for planned maintenance during non-critical periods rather than emergency workovers, reducing overall maintenance costs while maintaining equipment reliability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration enhances the reliability of artificial lift systems, reduces maintenance costs, and minimizes lost production by isolating electrical components from the hostile downhole environment, leading to increased well production and extended equipment life.
Implementation Method 1
The stator chamber comprises a cooling circuit for circulating coolant within the stator chamber
Implementation Method 2
The stator is configured to drive the rotor to rotate the impeller and induce well fluid flow in response to receiving power through the electrical connection
Data Source
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AI summary
An electric submersible pump (ESP) is described. The ESP includes a stator chamber, a stator within the stator chamber, a rotor, and an electrical connection. The stator chamber is configured to reside in a wellbore. The stator chamber is configured to attach to a tubing of a well. The stator chamber defines an inner bore having an inner bore wall that, when the stator chamber is attached to the tubing, is continuous with an inner wall of the tubing. The rotor is positioned within the inner bore of the stator chamber. The rotor includes an impeller. The rotor is configured to be retrievable from the well while the stator remains in the well. The stator is configured to drive the rotor to rotate the impeller and induce well fluid flow in response to receiving power through the electrical connection.