ESP Fallback Valve With Disc Openings to Prevent Sand Plugging
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Solution Overview
Problem
Conventional check valves in electric submersible pump (ESP) production tubing are ineffective in preventing sand fallback, leading to pump plugging and damage due to their inability to handle solid-laden fluids, causing operational issues and reduced lifespan.
Innovation Solution
A fallback prevention valve system that uses a set of discs with aligned openings to actuate between open and closed positions based on fluid flow direction, utilizing an independent shaft and impeller to prevent sand from entering the pump by blocking fluid flow when it falls, and a vent port to manage fluid flow and pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional check valves are used to prevent fluid fallback during ESP interruptions, then liquid fallback is prevented, but sand-laden fluid causes the valves to become stuck in the closed position and plug the pump stages
Solution Approach 1:
The valve is segmented into multiple discs with openings instead of a single solid closure element. This segmentation allows fluid to pass through the openings when the valve is closed, preventing sand accumulation that would stick the valve shut, while still blocking the main fallback flow path.
Solution Approach 2:
Different parts of the valve have different properties: the discs have openings for sand passage, the valve shaft rotates independently from the pump shaft, and the impeller creates differential pressure zones. This local differentiation allows the valve to handle both liquid fallback prevention and sand-laden fluid simultaneously.
2Reliability
If the valve closes to block sand fallback, then pump protection is improved, but fluid flow is blocked during normal operation
Solution Approach 1:
The valve transitions from a static closed state to a dynamic rotating state. During normal operation, the valve rotates to align openings for fluid passage. During fallback, the valve closes by rotating to misalign openings. This dynamic behavior allows the valve to provide protection when needed while maintaining productivity during operation.
Solution Approach 2:
The valve operates periodically, rotating open during normal production flow and closing during fallback conditions. The impeller creates periodic pressure differentials that drive this cyclic opening and closing action, ensuring the valve is in the correct position at the right time.
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
Effectively prevents sand from falling into the ESP pump during shutdown, reducing the risk of plugging and damage, while allowing fluid to flow freely during operation, thus enhancing the operational reliability and longevity of the ESP assembly.
Implementation Method 1
the fallback valve actuatable by a flow of fluid passing at least partially through the fallback valve
Implementation Method 2
the relief groove is fluidly coupled to the vent port and when the fallback valve is in the closed position, the relief groove is configured to guide production fluid outward along the rotatable disc to at least partially actuate the valve into the open position
Data Source
AI summary
A fallback prevention valve apparatus, system and method is described. An electric submersible pump (ESP) fallback prevention system includes an ESP assembly positioned in a downhole well, the ESP assembly including production tubing extending between a centrifugal pump and a surface of the downhole well such that during operation of the ESP assembly production fluid flows upward from the centrifugal pump through the production tubing to the surface, the production tubing including a fallback valve actuatable by the flow of production fluid, the fallback valve actuatable between an open position, wherein production fluid flowing upward through the fallback valve actuates the fallback valve into the open position, and a closed position, wherein production fluid flowing downward through the fallback valve actuates the fallback valve into the closed position, the closed position blocking sand carried by the production fluid from falling into the centrifugal pump.