Reverse Rotation PCP System for Solid Evacuation
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Solution Overview
Problem
Progressive cavity pumps (PCPs) face issues with solid materials settling on top of or in the pump during shutdown, leading to clogging and preventing restarts, due to the inability to effectively manage counter-clockwise rotation and torque control, which causes solid particles to enter and clog the pump.
Innovation Solution
The PCP system operates in a reverse mode by rotating counter-clockwise to pump fluids and suspended solids down the wellbore before shutdown, utilizing a permanent magnet motor drive and high-torque connections to manage torque and axial/circumferential forces, and a control system to monitor parameters and trigger reverse mode operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the PCP operates in normal production mode with clockwise rotation, then fluid is pumped from intake to discharge, but solid materials settle on top of or in the pump during shutdown causing clogging
Solution Approach 1:
The patent applies reverse rotation of the rotor (counter-clockwise direction) during shutdown to pump solids back down the wellbore. This inversion of the normal rotation direction prevents solid material accumulation in the pump by actively transporting solids away from the pump cavity, thereby maintaining restart capability while preserving production efficiency.
2Reliability
If the rotor rotates counter-clockwise during shutdown, then solids are pumped down the wellbore preventing settlement, but torque control and connection integrity become challenging
Solution Approach 1:
The patent segments the force management by using a high-torque connection specifically designed to handle circumferential forces during reverse rotation, while the sucker rod handles axial loads. This segmentation of force pathways allows the system to manage both torque and axial load effectively during counter-clockwise rotation, enabling reliable solid material evacuation without compromising connection integrity.
3Strength
If high-torque connections are used to maintain connection integrity during reverse rotation, then connection strength is improved, but device complexity increases
Solution Approach 1:
The patent applies local quality by designing a high-torque connection with specific geometric features (keyway, splines, or dovetail configuration) at the rotor-sucker rod interface to handle circumferential forces during reverse rotation. This localized enhancement of connection quality at the critical interface provides the necessary strength without requiring complex modifications throughout the entire device, thus achieving connection integrity with minimal added 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
This method prevents or reduces solid material settlement, maintains connection integrity, and allows for easier restarts by clearing solids and managing torque effectively, reducing the risk of clogging and disconnection during shutdown.
Implementation Method 1
a permanent magnet motor drive (PMM Drive or PMM) configured to be disposed at a surface of the well. The PMM Drive is configured to transmit power to the downhole pump and support the axial load (weight and hydraulic thrust) from the rod string
Data Source
AI summary
A progressive cavity pump (PCP) system includes a PCP with a rotor rotatably disposed in a stator, a permanent magnet motor, sucker rod(s), and a control system. The rotor is coupled to one of the sucker rods via a high-torque connection that allows for counter clockwise rotation without loosening the connection between the rotor and sucker rod. The control system operates the system in a production mode by rotating the rotor clockwise. Upon manual input by a user, or automatic triggering when protections settings of the control system call for a shutdown or cleanout or when the control system senses an imminent pump shutdown, the control system operates the system in a reverse mode by rotating the rotor counterclockwise. The reverse mode pumps fluids and suspended solid particles down into the well prior to pump shutdown to inhibit the solids from clogging the pump or preventing the pump from restarting.