Downhole Pump Reverse Rotation Detection
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Solution Overview
Problem
Downhole pumping systems face challenges in reliably detecting reverse rotation of electric submersible pumps at startup, leading to wasted time and potential premature failure due to high rubbing loads and debris issues, especially in unconventional wells.
Innovation Solution
A downhole pumping system incorporating a rotational movement sensor and control system that includes a processing system to determine the rotational parameters of the shaft, such as direction, speed, and acceleration, and a control system to correct the rotation based on these parameters, using a rotational transmitter assembly with a permanent magnet and stationary sensor to output signals related to the shaft's rotational parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional downhole gauges are used without rotational sensors, then device complexity is reduced, but the ability to detect reverse rotation at startup is insufficient leading to increased downtime and potential pump failure
Solution Approach 1:
The patent replaces complex mechanical rotation detection mechanisms with electromagnetic sensing. A magnetic sensor detects the position of a magnetic indicator on the motor shaft, providing rotational direction and speed information without mechanical contact. This electromagnetic approach simplifies the overall system while enabling reliable reverse rotation detection at startup.
Solution Approach 2:
The patent introduces a magnetic indicator as an intermediary element between the motor shaft and the magnetic sensor. This magnetic indicator converts the mechanical rotation into a detectable magnetic field variation, enabling non-contact measurement of rotational parameters. The magnetic indicator acts as a mediator that bridges the mechanical and electromagnetic domains.
2Reliability
If sensorless control is used to avoid adding rotational sensors, then device complexity is reduced, but the robustness to rapid load changes is insufficient
Solution Approach 1:
The patent implements a feedback control system where the magnetic sensor continuously monitors shaft rotation and provides real-time information about rotational direction and speed to the control system. This feedback enables the controller to detect rapid load changes and adjust motor operation accordingly, providing robustness without requiring complex sensorless estimation algorithms.
3Productivity
If the pump operates in reverse direction at startup, then the pump can still pump fluid, but high rubbing loads and debris cause premature failure
Solution Approach 1:
The patent performs preliminary detection of rotational direction at startup before the pump begins normal operation. The magnetic sensor detects whether the motor is rotating in the correct direction immediately upon startup, allowing the control system to correct reverse rotation before it can cause high rubbing loads and debris accumulation that lead to premature pump failure.
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
Enables prompt detection and correction of reverse rotation, reducing downtime, preventing premature pump failure, and minimizing debris-related damage, thus enhancing operational efficiency and reducing costs, especially in challenging well conditions.
Implementation Method 1
a rotational transmitter assembly with a permanent magnet and stationary sensor to output signals related to the shaft's rotational parameters
Data Source
AI summary
An apparatus and method for sensing a rotational parameter of a rotating member of a downhole pumping system. The apparatus is capable of detecting motor rotation and pump operating conditions and includes control systems for methods utilizing the rotational parameters to control the operation of the downhole pumping system.