Submersible Pump SRM Drive for Breaking Free From Well Jams
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Solution Overview
Problem
Induction motors used in electric submersible pumps (ESPs) have limited torque when stalled, making it difficult to break free from jams caused by sediments or heavy hydrocarbons, which hampers efficient fluid production in subsurface wells.
Innovation Solution
The use of a switched reluctance motor (SRM) with stator coils in multiples of three, driven by surface electronics via a three-conductor cable, utilizing push-pull drivers and recirculation diodes to provide full torque and high-speed operation without permanent magnets, allowing the motor to break free from jams.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If an induction motor is used in the ESP, then the motor structure is simple and reliable, but the torque is limited when the rotor is stalled, making it difficult to break free from jams
Solution Approach 1:
The patent changes the fundamental operating parameters of the motor by switching from induction motor principles to switched reluctance motor principles. This involves changing the control method from rotating magnetic field induction to sequential coil energization, which fundamentally alters the torque-generation mechanism and enables full stalled torque capability.
Solution Approach 2:
The switched reluctance motor dynamically controls the energization of stator coils based on rotor position and operational requirements. The controller can dynamically adjust which coils are energized and to what extent, enabling the motor to deliver full torque when stalled and optimize performance during normal operation.
2Reliability
If a switched reluctance motor is used to provide full torque when stalled, then the ability to break free from jams is improved, but the motor requires complex control electronics and push-pull drivers
Solution Approach 1:
The patent employs push-pull driver circuits that can perform multiple functions: driving the stator coils during normal operation, providing full torque when stalled, and serving as part of the control interface. These drivers are integrated with the existing cable infrastructure, reducing the need for separate control systems.
Solution Approach 2:
The switched reluctance motor system uses the existing three-conductor cable infrastructure to carry both power and control signals. The motor controller and push-pull drivers are designed to work within the constraints of this existing infrastructure, making the system self-sufficient without requiring additional dedicated control wiring.
3Use of energy by moving object
If the number of stator coils is a multiple of three to enable three-phase operation, then the motor efficiency is improved, but the cable requires more conductors
Solution Approach 1:
The patent merges the power transmission and control functions into a single three-conductor cable system. The push-pull driver architecture allows the same three conductors to carry both the three-phase power signals and the control signals, eliminating the need for separate control wiring and reducing the overall conductor count.
Solution Approach 2:
Each of the three conductors serves multiple functions: carrying phase power signals during normal operation and serving as control lines for the push-pull drivers. This multi-functional use of the conductors maintains the three-phase configuration for efficiency while avoiding the need for additional conductors.
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 SRM achieves full torque when stalled and operates at high speeds, enhancing the ability to overcome jams and improve fluid production efficiency in ESP applications.
Implementation Method 1
a switched reluctance motor (SRM) comprising stator coils... surface electronics that drive the SRM
Data Source
AI summary
An electric submersible pump (ESP) including: a switched reluctance motor (SRM) including stator coils. The number of the stator coils is a multiple of three, surface electronics that drive the SRM, a cable that connects the SRM to the surface electronics. The cable includes conductors in a number equal to the number of the stator coils, each cable includes a push-pull driver that connects the cable to a ground, a DC voltage different from the ground, or disconnects the cable.