ESP Pump Speed Control for Sub-cooled Fluid Maintenance
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Solution Overview
Problem
In hydrocarbon producing wells, submersible pumps face challenges in preventing cavitation due to hot water condensate flashing into vapor, which can affect pump performance, especially when the fluid is close to its saturation point.
Innovation Solution
The ESP assembly incorporates sensors to monitor wellbore temperature and pressure, allowing for real-time adjustment of pump operation to maintain the fluid in a sub-cooled liquid state by controlling the pump speed and pressure at the inlet, ensuring the fluid remains above its saturation pressure to prevent vaporization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If steam injection is used to heat crude past its pour point, then fluid flow from formation into wellbore is enabled, but hot water condensate flashes into vapor causing pump cavitation
Solution Approach 1:
The system proactively monitors temperature and pressure conditions before vaporization occurs, using sensors to detect when fluid approaches saturation point and adjusts pump operation in advance to prevent cavitation
Solution Approach 2:
The system continuously monitors wellbore temperature and pressure, compares readings against saturation conditions, and automatically adjusts pump speed based on feedback to maintain fluid in sub-cooled state and prevent vaporization
2Productivity
If pump speed is increased to maintain productivity, then fluid flow increases, but fluid temperature rises closer to saturation point increasing vaporization risk
Solution Approach 1:
The pump operating speed is made dynamically adjustable rather than fixed, allowing the system to optimize between productivity and vaporization prevention by continuously adapting pump speed based on real-time temperature and pressure conditions
Solution Approach 2:
The system changes operational parameters (pump speed, flow rate) based on measured temperature and pressure to maintain fluid conditions below saturation point, preventing vaporization while maximizing productive flow
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 approach effectively prevents cavitation and maintains pump performance by ensuring the fluid remains sub-cooled, optimizing fluid flow and reducing the risk of vaporization, thereby enhancing the efficiency and reliability of the ESP system.
Implementation Method 1
The ESP assembly incorporates sensors to monitor wellbore temperature and pressure
Implementation Method 2
maintain the fluid in a sub-cooled liquid state by controlling the pump speed and pressure at the inlet, ensuring the fluid remains above its saturation pressure to prevent vaporization
Implementation Method 3
The hot water condensate is generally close to its saturation point and thus prone to flashing back into a vapor state
Data Source
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AI summary
A method of operating an electrical submersible pumping system 20 that includes realtime monitoring of fluid from a wellbore 7 and adjusting pump 20 speed so the fluid entering the pump 20 remains subcooled. The method can include adding sensors 37, 41 within the wellbore 7 and digitally storing fluid data accessible by a pump controller 32. The pump 20 speed can be increased or decreased by adjusting the frequency of the electrical power delivered to a motor 26 that drives the pump 20.