Polygonal Liner Seals Stator in Submersible Canned Motor Pump
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Solution Overview
Problem
Current electrical submersible pump assemblies with canned motors face issues with corrosive well fluids entering the stator, causing damage due to leaky seals, which compromise the motor's integrity and require frequent servicing.
Innovation Solution
A hermetically sealed system is implemented using a motor-pump unit with a stator and rotor assembly, where a non-magnetic liner with a polygonal cross-section is welded to the motor housing to prevent wellbore fluids from reaching the stator, and a distributed sensing system is integrated for monitoring and control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If a hermetically sealed system is implemented to isolate the stator from wellbore fluids, then motor longevity is enhanced, but device complexity increases
Solution Approach 1:
The patent eliminates complex hermetic sealing systems by removing seals entirely. The motor achieves longevity not through complex sealing but through direct exposure design combined with corrosion-resistant materials and the structural integrity of the polygonal liner, thereby reducing device complexity while maintaining durability.
Solution Approach 2:
Instead of implementing a complex hermetic seal throughout the motor assembly, the patent applies localized protection through the polygonal liner that directly contacts the wellbore environment, while the stator and rotor operate in a controlled internal environment. This localized approach extends motor longevity without requiring complex system-wide sealing.
2Object-affected harmful factors
If seals are used to isolate the stator, then fluid ingress is prevented, but mechanical and process issues outside operating envelope cause seal failure
Solution Approach 1:
The patent removes seals from the system entirely, eliminating their inability to adapt to conditions outside the operating envelope. The motor accepts direct exposure to varying wellbore conditions through the polygonal liner, with the stator designed to withstand these environments without relying on seals that fail under mechanical stress, temperature extremes, or pressure fluctuations.
Solution Approach 2:
The patent changes the operational parameters by allowing the stator to operate directly in contact with wellbore fluids through the polygonal liner, rather than maintaining a sealed environment. This parameter change enables the system to adapt to varying wellbore conditions without seal failure, as the design accepts environmental variability rather than attempting to exclude it through seals.
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
The solution effectively prevents fluid ingress, enhancing motor longevity and reducing maintenance needs by maintaining a separate rotor cavity for alternative lubrication and cooling, while providing accurate flow measurements and real-time monitoring.
Implementation Method 1
a liner located along an interior surface of the interior cavity and hermetically seals the stator body from wellbore fluid
Implementation Method 2
The motor-pump unit has a rotor assembly located within the interior cavity of the stator. The rotor assembly includes a rotor shaft, a rotor member, and an intermediate rotor bearing assembly
Data Source
AI summary
Systems and methods for producing fluids from a subterranean well include an electrical submersible pump assembly with a motor-pump unit. The motor-pump unit has a motor housing and a stator is located within the motor housing. The stator has a stator body with an interior cavity. A rotor assembly is located within the interior cavity of the stator. The rotor assembly includes a rotor shaft extending along the central axis of the stator, a rotor member, and an intermediate rotor bearing assembly. The rotor member and the intermediate rotor bearing assembly circumscribe the rotor shaft. An impeller is mounted on the rotor shaft and located within the interior cavity of the stator. A liner with a polygonal cross section is located along an interior surface of the interior cavity. The liner is secured to the motor housing and seals the stator body from a wellbore fluid.