Safety VFD for ESP Over-Pressurization Prevention
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Solution Overview
Problem
Electrical submersible pumps (ESPs) can cause over-pressurization of downstream piping networks when a blockage occurs, leading to potential rupture, fire, and explosion due to exceeding the maximum allowable operating pressure (MAOP), which existing safety systems struggle to prevent effectively.
Innovation Solution
Implementing a method using a processor and sensors to continuously monitor ESP operating parameters and compare them to predetermined thresholds, adjusting the ESP's input parameters, such as frequency or current, via a variable frequency drive (VFD) controller to prevent over-pressurization by leveraging existing ESP sensors and inexpensive VFD equipment, thereby avoiding the need for costly high-integrity pressure protection systems (HIPPS).
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If ESP continues to pump fluid under shut-in condition to maintain production, then productivity is improved, but piping network safety deteriorates due to over pressurization risk
Solution Approach 1:
The system continuously monitors ESP operating parameters (current, power, speed) and compares them against pre-determined thresholds that indicate potential over-pressurization conditions. When thresholds are exceeded, the system automatically adjusts ESP operation to prevent piping network over-pressurization, creating a closed-loop feedback control system that balances productivity with safety.
Solution Approach 2:
The system pre-determines operating parameter thresholds based on the piping network's maximum allowable operating pressure (MAOP) and expected parameters during blocked outlet conditions. By establishing these thresholds in advance and monitoring against them, the system takes preliminary action to prevent over-pressurization before it occurs, rather than reacting after the problem arises.
2Reliability
If costly high-integrity pressure protection systems (HIPPS) are installed to prevent over-pressurization, then piping network safety is improved, but device complexity and cost increase
Solution Approach 1:
The system utilizes existing ESP sensors and control infrastructure to monitor and regulate pressure, allowing the ESP system to serve its own safety function. This self-service approach eliminates the need for separate, complex HIPPS systems while maintaining adequate safety through intelligent monitoring and control of the existing equipment.
Solution Approach 2:
The system makes the existing ESP control system multi-functional by enabling it to perform both its primary function of fluid production and its secondary function of pressure safety management. By programming the existing VFD and control electronics to monitor operating parameters and adjust operation accordingly, the system achieves safety functions without adding dedicated safety equipment.
Data Source
AI summary
A method of preventing over-pressurization of a downstream piping network, using a safety VFD, includes continuously receiving, from sensors attached to an ESP, values representing input/output operating parameters of the ESP. The ESP is disposed in a wellbore and fluidically coupled to a piping network disposed at a surface of the wellbore. The method also includes comparing one or more values to operating parameter thresholds determined based on at least one of 1) expected ESP parameters during a blocked outlet condition of the piping network or 2) an association of the operating parameter threshold with a fluidic pressure of the piping network that has a potential of reaching an MAOP of the piping network. The method also includes determining that values meet the threshold and changing an input parameter of the ESP to change a fluidic output of the ESP to prevent the over pressurization of the downstream piping network.