ESP Fallback Valve With Rotating Discs for Sand Blocking
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Solution Overview
Problem
Conventional check valves in electric submersible pump (ESP) systems are ineffective in preventing sand fallback, leading to pump plugging and damage due to their inability to handle solid-laden fluids, causing operational failures and reduced ESP assembly 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 mechanism to prevent sand from entering the pump, and includes a vent port system to manage fluid flow and pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional check valves are used to prevent fluid fallback, then liquid fallback is reduced, but sand fallback prevention fails and the valve becomes stuck in closed position
Solution Approach 1:
The valve is segmented into multiple functional components: a body, a rotatable disc with flow passages, and a shaft with impeller. The rotatable disc is divided into sectors that can independently align or misalign with the body's flow passages, allowing the valve to handle both liquid and sand fallback prevention through rotational positioning rather than simple open/closed states.
Solution Approach 2:
The valve transitions from a static check valve design to a dynamic system where the rotatable disc can rotate to different positions based on flow direction. The impeller on the shaft rotates in response to fluid flow, automatically positioning the disc to either align or misalign flow passages, enabling adaptive response to both upward and downward fluid movement including sand fallback scenarios.
2Reliability
If the valve closes to prevent sand fallback, then pump protection is improved, but fluid flow blocking occurs when pump restarts
Solution Approach 1:
The valve uses dynamic rotational positioning of the disc rather than static open/closed states. During normal pump operation, upward fluid flow rotates the impeller to align the disc's flow passages with the body passages, maintaining full fluid flow. When sand fallback occurs, the reverse flow rotates the disc to misalign passages, blocking sand while the aligned passages allow controlled fluid bypass, thus protecting the pump without completely blocking production flow.
Solution Approach 2:
The rotatable disc with its flow passages acts as an intermediary between the upstream and downstream flow paths. Instead of a direct open/closed valve action, the disc's rotational position mediates flow by either aligning passages for full flow or misaligning them to block sand while allowing controlled bypass, preventing complete flow interruption during pump restart.
3Device complexity
If a simple check valve design is used, then device complexity is reduced, but effectiveness against sand fallback is lost
Solution Approach 1:
The valve is segmented into modular components: a body with flow passages, a rotatable disc with corresponding passages, and a shaft with impeller. This segmentation allows each component to perform a specific function while maintaining overall simplicity. The disc rotation mechanism provides sand fallback prevention capability without requiring complex control systems, actuators, or multiple valve elements, thus achieving enhanced reliability through moderate structural complexity.
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 fallback into the ESP pump, reducing the risk of plugging and damage, ensuring continuous operation and extended ESP assembly lifespan by using the potential energy of production fluid to actuate the valve between open and closed positions.
Implementation Method 1
an impeller coupled to the valve shaft turns the valve shaft to actuate the first disc between the open position and the closed position
Implementation Method 2
the relief groove is fluidly coupled to the vent port and when the fallback valve is in the closed position, the depression is aligned with an opening of a nonrotatable disc
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.