ESP Intake Pressure Control via Annular Fluid Recycle
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Solution Overview
Problem
In hydrocarbon well development, maintaining fluid level is challenging with Electrical Submersible Pumps (ESPs) due to low intake pressure, leading to frequent cycling and reduced pump lifespan, which can result in unnecessary workover operations and production losses.
Innovation Solution
An automated pressure control system that uses a production tubing string, submersible pump, Christmas tree, pressure control flowline, and control valves to maintain submersible pump intake pressure by returning production fluid to the annulus based on measured intake pressure, ensuring continuous operation of the ESP.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ESP is cycled based on low intake pressure, then pump protection is achieved, but pump lifespan is reduced and workover operations become necessary
Solution Approach 1:
The system continuously monitors intake pressure and automatically adjusts the recycle valve position based on real-time pressure feedback. When intake pressure drops below the threshold, the controller opens the recycle valve to return fluid to the annulus, increasing the fluid column height and restoring adequate intake pressure. This closed-loop feedback mechanism protects the pump without requiring cycling, thereby extending pump lifespan while maintaining reliability.
Solution Approach 2:
The system changes the operational parameter from binary cycling (on/off) to continuous modulation of the recycle valve position. By varying the valve opening degree based on intake pressure conditions, the system maintains fluid column height within an optimal range, ensuring continuous pump operation with adequate intake pressure without the need for frequent cycling.
2Productivity
If ESP operates continuously, then productivity is maintained, but intake pressure may drop below threshold causing pump damage
Solution Approach 1:
The system uses continuous intake pressure monitoring to provide real-time feedback to the controller. When pressure approaches the critical threshold, the controller actively adjusts the recycle valve to maintain pressure within the safe operating range, enabling continuous pump operation without compromising reliability.
Solution Approach 2:
The system takes preliminary action by opening the recycle valve before intake pressure drops to dangerous levels. The controller monitors pressure trends and proactively adjusts the valve position to prevent pressure from falling below the threshold, thereby avoiding pump damage while maintaining continuous operation.
3Device complexity
If fluid level is not maintained, then system complexity is reduced, but pump intake pressure becomes insufficient
Solution Approach 1:
The system is self-regulating, using the pump's own intake pressure as the control signal. The controller automatically adjusts the recycle valve based on real-time pressure feedback, making the system self-service without requiring external intervention or complex external control mechanisms. This maintains adequate intake pressure while keeping the control logic relatively simple.
Solution Approach 2:
The recycle valve acts as an intermediary element between the production flowline and the annulus. By controlling the flow of returned fluid through this intermediate valve, the system regulates the fluid column height in the annulus, thereby maintaining adequate intake pressure without requiring direct complex interaction between multiple system components.
4Stress or pressure
If recycle valve is opened to maintain fluid level, then intake pressure is restored, but produced fluid is lost to annulus
Solution Approach 1:
The system applies partial action by opening the recycle valve only to the extent necessary to restore adequate intake pressure. The controller modulates the valve position to achieve the minimum required fluid column height, avoiding excessive recycling of fluid. This minimizes fluid loss to the annulus while still achieving the primary objective of maintaining sufficient intake pressure for continuous pump 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
This solution allows ESPs to run continuously, prolongs their lifespan, reduces workover costs, and minimizes production losses by maintaining a stable fluid column and intake pressure, avoiding unnecessary cycling and incorrect attribution of well performance issues.
Implementation Method 1
The pressure control flowline may fluidly connect the production flowline with the annulus... The one or more control valves may be configured to control a flow of produced fluids in the production flowline and the pressure control flowline... based on an intake pressure of the submersible pump
Data Source
AI summary
A well production system may include a production tubing string, a submersible pump, a Christmas tree, a pressure control flowline, one or more control valves, and a control system. The production tubing string may include a production bore and an annulus and be disposed within a wellbore. The submersible pump may be disposed within the wellbore and include an inlet and an outlet. The Christmas tree may have an inlet configured to receive produced fluids from the submersible pump and an outlet in fluid communication with a production flowline. The pressure control flowline may fluidly connect the production flowline with the annulus. The one or more control valves may be configured to control a flow of produced fluids in the production flowline and the pressure control flowline. The control system may be configured to control a position of the one or more control valves.