ESP Motor Shaft Rotation Sensing and Backspin Prevention
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Solution Overview
Problem
The challenge in hydrocarbon production is the unsafe and inefficient operation of electric submersible pumps (ESPs) due to backspin, which occurs when the motor is not properly controlled, leading to hazardous conditions and reduced efficiency as power is used to counteract the backspin, potentially causing motor failure and inaccurate fluid pumping calculations.
Innovation Solution
A system that senses the rotation speed and direction of the motor shaft in an ESP using identifiers such as magnetic splines and sensors, allowing for precise determination of the motor's state, enabling controlled power application to prevent backspin and optimize pumping efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the motor is not powered when fluid drains back down, then energy consumption is reduced, but the motor shaft rotates in reverse direction causing hazardous backspin conditions
Solution Approach 1:
The system uses sensors to detect the rotation direction of the motor shaft and provides feedback to the controller. When reverse rotation (backspin) is detected, the controller activates the check valve to close, preventing further backspin. This closed-loop feedback mechanism allows the system to respond dynamically to hazardous conditions while minimizing unnecessary energy consumption during normal operation.
Solution Approach 2:
The system continuously monitors motor shaft rotation using sensors before hazardous backspin conditions fully develop. By detecting early signs of reverse rotation and preemptively activating the check valve, the system prevents the development of dangerous backspin conditions rather than reacting after the hazard has fully manifested.
2Object-affected harmful factors
If a check valve is installed to prevent backspin, then safety is improved, but device complexity increases
Solution Approach 1:
The system uses the motor shaft's own rotation to drive the check valve mechanism. The valve is positioned such that reverse rotation of the motor shaft automatically triggers valve closure through mechanical interaction, eliminating the need for separate actuators, motors, or complex electronic control systems. The system essentially uses itself to prevent the hazardous condition it detects.
Solution Approach 2:
The check valve acts as an intermediary mechanical element between the motor shaft and the fluid flow. It translates the rotational motion of the motor shaft into a linear closing action that blocks fluid flow, providing a simple mechanical mediation that prevents backspin without requiring complex control systems.
3Reliability
If power is applied to counteract backspin, then motor protection is improved, but energy consumption increases and pumping efficiency decreases
Solution Approach 1:
The system extracts and isolates the backspin prevention function into a separate mechanical check valve mechanism, independent of the motor's power system. This allows the motor to remain powered for normal pumping operations while the check valve independently handles backspin prevention, eliminating the need to waste motor power counteracting reverse rotation.
Solution Approach 2:
The system converts the potentially harmful reverse rotation force into a beneficial mechanism by using the motor shaft's own reverse motion to trigger check valve closure. The harmful backspin force that would normally damage the motor is instead utilized to automatically activate the protective valve, turning a dangerous condition into a self-activating safety feature.
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 solution enhances safety by preventing hazardous backspin conditions and improves efficiency by ensuring proper power application, reducing motor stress and accurately calculating fluid pumped, thus minimizing downtime and operational costs.
Implementation Method 1
A system that senses the rotation speed and direction of the motor shaft in an ESP using identifiers such as magnetic splines and sensors
Data Source
AI summary
One or more sensors are mounted on a collar proximate to a motor shaft of a motor. The motor is associated with an electric submersible pump (ESP) located in a wellbore of a geological formation. The one or more sensors sense one or more identifiers located on the motor shaft of the motor. One or more of a rotation direction and rotation speed of the motor shaft is determined based on the sensing of the one or more identifiers. The motor is powered to pump fluid from a reservoir in the geological formation to a surface of the geological formation based on the one or more of the rotation direction and rotation speed of the motor shaft.