Segmented Stator Electric Submersible Pump
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Solution Overview
Problem
Well production declines over time due to declining reservoir pressures, necessitating artificial lift systems like electric submersible pumps to maintain pressure and extend well life.
Innovation Solution
A downhole-type electric submersible pump system with a stator assembly, rotor assembly, and magnetic coupling, where the electric machine is configured to induce torque using windings and permanent magnets, and supported by non-conductive bearing members, maintaining internal pressure within a housing fluid.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If electric submersible pumps are used to increase driving pressure, then well production is maintained or extended, but device complexity and manufacturing cost increase
Solution Approach 1:
The electric machine is divided into multiple axially-spaced stator sections with corresponding rotor sections, where each section can be independently manufactured and assembled. The conductors span across multiple stator sections, creating a modular structure that reduces overall device complexity while maintaining pumping capability.
Solution Approach 2:
The rotor assembly is carried within and supported by the stator assembly, with bearing support members positioned in gaps between stator sections. This nested configuration consolidates multiple components into a compact downhole package, extending well life without proportionally increasing device complexity.
2Power
If conductors span entire length of stator assembly, then torque induction is improved, but manufacturing precision requirements increase
Solution Approach 1:
The stator assembly is segmented into multiple axially-spaced sections with gaps between them. Conductors span across these sections and gaps, allowing the system to achieve full-length torque induction while manufacturing and assembling shorter, more manageable sections with reduced precision requirements compared to a single continuous stator.
Solution Approach 2:
Bearing support members made from electrically non-conductive material are positioned in the gaps between stator sections. These intermediary components support the conductors at specific positions while maintaining electrical isolation, enabling conductor continuity for torque induction without requiring precision alignment across conducting gaps.
3Reliability
If bearing support members are made from electrically non-conductive material, then electrical isolation is improved, but mechanical strength may be reduced
Solution Approach 1:
Bearing support members are made from electrically non-conductive materials that provide both electrical isolation and sufficient mechanical strength to support conductors and rotor assemblies in harsh downhole environments. This composite material approach resolves the contradiction between electrical isolation requirements and mechanical strength needs.
4Power
If multiple axially-spaced stator sections are used, then torque distribution is improved, but device complexity increases
Solution Approach 1:
The stator assembly comprises multiple stator sections axially arranged and spaced apart along the longitudinal axis, with each section containing windings that induce torque in corresponding rotor sections. This segmentation improves torque distribution along the axial length while allowing modular manufacturing and assembly, offsetting the increase in component count through standardized sections.
Solution Approach 2:
Multiple stator sections and rotor sections are combined into a single integrated electric machine assembly that functions as one unified torque-generating device. The conductors span across stator sections and gaps, merging the functionality of multiple sections into a coordinated system that achieves improved torque distribution without proportionally increasing overall device complexity.
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 system effectively increases fluid flow and pressure in the wellbore, extending the well's productive life by enhancing torque transfer and pressure maintenance, even in challenging downhole conditions.
Implementation Method 1
The electric machine windings are configured to induce a torque in a rotor assembly responsive to receiving electrical power at the stator assembly
Implementation Method 2
A magnetic coupling is configured to couple the impeller and the electric machine to transfer a rotation between the impeller and the electric machine
Data Source
AI summary
Certain aspects of the subject matter described here can be implemented in a downhole-type electric submersible pump system. An electric machine can be disposed downhole in a wellbore. The electric machine is coupled to rotate with an impeller that can be disposed downhole in the wellbore. The electric machine includes a stator assembly with at least three stator sections axially arranged and spaced apart from each other along a longitudinal axis of the electric machine. The electric machine also includes a rotor assembly with at least three rotor sections arranged axially along the longitudinal axis of the electric machine. The rotor assembly is carried within and supported to rotate by the stator assembly.