Well Stimulation Pump Control for Cavitation Prevention
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Solution Overview
Problem
Hydraulic fracturing pumps experience cavitation due to high operating pressures, leading to premature wear of internal components and decreased efficiency, as the fracturing fluid undergoes cavitation during the pumping process.
Innovation Solution
A control system that monitors pump operating parameters and compares them to predefined cavitation maps to determine if cavitation is present, adjusting the pump's speed and inlet pressure in real-time to prevent or reduce cavitation, using a model-based closed-loop strategy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If the pump operates at high pressure to achieve hydraulic fracturing, then the fracturing function is effective, but cavitation occurs causing component wear and efficiency loss
Solution Approach 1:
The system performs preliminary action by predicting cavitation conditions before they occur using a cavitation map and current operating parameters. The controller proactively adjusts pump speed or inlet pressure to prevent cavitation, rather than waiting for damage to occur. This preventive approach extends component life while maintaining high pressure operation capability.
Solution Approach 2:
The system implements feedback by continuously monitoring pump operating parameters (speed, inlet pressure) and comparing them against the cavitation map. The controller receives feedback on operating conditions and automatically adjusts parameters to keep the pump operating outside the cavitation zone, resolving the contradiction between maintaining high pressure and preventing cavitation-induced wear.
2Productivity
If the pump operates at high speed to increase productivity, then fracturing efficiency improves, but cavitation risk increases causing efficiency loss
Solution Approach 1:
The system applies dynamics by making pump operating parameters adjustable and adaptable in real-time. The controller dynamically modifies pump speed or inlet pressure based on current conditions and cavitation predictions. This dynamic adjustment allows the system to maintain high productivity when conditions permit while preventing cavitation when risks are present, resolving the contradiction between speed and cavitation risk.
Solution Approach 2:
The system implements parameter changes by modifying pump operating parameters (speed, inlet pressure) to avoid cavitation conditions. The controller changes these parameters based on the cavitation map comparison, allowing the pump to operate at high speeds for productivity when safe, while preventing cavitation by adjusting parameters when conditions indicate risk, thus resolving the contradiction between productivity and cavitation harm.
3Reliability
If the pump maintains high inlet pressure to prevent cavitation, then cavitation is reduced, but the ability to deliver high pressure to the well decreases
Solution Approach 1:
The system uses dynamics by making inlet pressure adjustable rather than fixed. The controller dynamically modifies inlet pressure only when cavitation is predicted, allowing the system to maintain high outlet pressure capability for most of the time while temporarily adjusting inlet pressure to prevent cavitation. This dynamic approach resolves the contradiction between cavitation prevention and outlet pressure capability.
Solution Approach 2:
The system implements parameter changes by selectively modifying inlet pressure based on cavitation predictions. Rather than maintaining constantly high inlet pressure, the controller changes this parameter only when the cavitation map indicates risk. This allows the system to preserve outlet pressure capability for effective fracturing while preventing cavitation through targeted parameter adjustments, resolving the contradiction between these two requirements.
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 reduces or eliminates cavitation, thereby increasing pumping efficiency and minimizing wear on pump components by automatically adjusting the pump's operation based on fluid pressure and speed measurements.
Implementation Method 1
A pressure sensor is disposed to measure a fluid pressure at a location between the inlet check valve and the inlet of the pump
Implementation Method 2
A speed sensor is disposed to measure a speed of the pump at the drive mechanism
Implementation Method 3
the fracturing fluid may undergo cavitations during the pumping process and, especially, within the pump. Such cavitation can prematurely wear internal pump components and decrease pump efficiency
Data Source
AI summary
A pumping system for use in a well stimulation application includes a pump controlled by a controller, the controller operating to monitor operation of the pump and determine when cavitation is present or imminent in the pump. When cavitation is present, the controller automatically adjusts an operating condition of the pump reduce pump speed or increase a fluid pressure at the pump inlet.