Pressure Exchanger Rotor Speed Control for Oscillation Management
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Solution Overview
Problem
Pressure oscillations generated by rotary pressure exchangers in oil and gas operations cause damage to piping networks and downstream equipment, and existing technologies fail to effectively control these oscillations to enhance the operational life of high-pressure pumps and wellsite equipment.
Innovation Solution
A system comprising pressure exchangers with a controller that adjusts the rotational speed and position of the rotor to control the frequency and phase of pressure oscillations, allowing for the reduction or amplification of combined pressure oscillations in the fluid stream injected into a wellbore, thereby minimizing equipment damage and extending pump life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If pressure exchangers operate at high rotational speeds to increase productivity, then fluid pressurization efficiency improves, but pressure oscillations increase causing equipment damage
Solution Approach 1:
The system dynamically adjusts the rotational speed of pressure exchanger rotors in real-time to control pressure oscillation frequencies. The controller modulates rotor speeds to avoid resonant frequencies of the piping network while maintaining productive fluid pressurization, transforming a static operating condition into a dynamically controlled process that adapts to system characteristics.
Solution Approach 2:
The invention changes the operational parameters of pressure exchangers by controlling rotational speed and phase relationships between multiple rotors. By adjusting these parameters, the system can shift pressure oscillation frequencies away from harmful resonant modes of the piping network, thereby reducing equipment damage while maintaining pressurization efficiency.
2Productivity
If multiple pressure exchangers are used to increase fluid flow capacity, then productivity improves, but combined pressure oscillations amplify causing greater equipment damage
Solution Approach 1:
The system introduces asymmetry in the operation of multiple pressure exchangers by controlling their rotors to rotate at different speeds or phases. This asymmetric operation causes pressure oscillations from individual exchangers to cancel each other out through destructive interference, reducing the amplitude of combined oscillations in the merged fluid stream while maintaining high flow capacity.
Solution Approach 2:
The invention converts the harmful effect of multiple pressure sources into a beneficial cancellation effect. By carefully controlling the phase and speed relationships between multiple rotors, the system transforms what would normally be amplifying oscillations into cancelling oscillations, where the combined effect is less harmful than individual contributions.
3Duration of action of moving object
If rotor speed is increased to reduce operational time, then duration of action decreases, but pressure oscillation frequency increases causing more equipment damage
Solution Approach 1:
The system employs dynamic speed control where rotor rotational speeds are continuously adjusted based on real-time monitoring of pressure oscillation frequencies. This dynamic approach allows the system to maintain high productivity by operating at optimal speeds while avoiding resonant frequencies that would cause equipment damage, thereby decoupling the relationship between operational speed and harmful oscillations.
Solution Approach 2:
The invention implements a feedback control system where pressure oscillation measurements are used to adjust rotor speeds. Sensors detect pressure oscillation frequencies in the fluid stream, and the controller uses this feedback information to modulate rotor speeds, creating a closed-loop system that automatically avoids harmful resonant conditions while maintaining efficient operation.
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 controls pressure oscillations, reducing equipment damage and increasing the operational life of high-pressure pumps and wellsite equipment by modulating the rotational speed and position of the rotor in pressure exchangers, ensuring efficient fluid injection into subterranean formations.
Implementation Method 1
The rotor rotates in a housing via a fluid-lubricated bearing
Implementation Method 2
During operation, the pressure exchangers generate attendant medium frequency pressure oscillations caused by the rotary valves
Data Source
AI summary
Apparatus and methods for utilizing pressure exchangers as a source of pressure oscillations. An example method includes operating a plurality of pressure exchangers to pressurize a stream of fluid, injecting the pressurized stream of fluid into a wellbore extending into a subterranean formation, and controlling rotational speed and rotational position of a rotor of each of the pressure exchangers to control amplitude and/or frequency of pressure oscillations within the pressurized stream of fluid being injected into the wellbore.