Downhole Sand Protection Device with Axial Shelves
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Solution Overview
Problem
Conventional sand protection devices for submersible pumps in wells are ineffective in preventing sand from settling and forming plugs, leading to reduced pump efficiency and costly workovers due to sand accumulation, as they allow finer particles to reach the pump and are not fully flushable, and external conditions hinder sand removal.
Innovation Solution
A downhole tool with a housing and axially spaced shelves for collecting sand, combined with a restrictor assembly that allows fluid flow in one direction while partially restricting it in the opposite direction, using features like castellated ball, poppet, or flapper valves to prevent sand from reaching the pump and facilitate easy removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional sand protection devices divert sand to an annular chamber, then sand is diverted away from the pump, but finer particles still reach the ESP and cannot be entirely flushed due to geometrical design
Solution Approach 1:
The device segments the sand separation function into multiple shelves with different geometries. The first shelf has a first geometry for initial sand collection, while the second shelf has a second geometry for finer particle collection. This segmentation allows each shelf to target different particle sizes and settling characteristics, achieving more complete sand removal than a single-chamber design.
Solution Approach 2:
The invention adds the vertical dimension by stacking shelves at different heights within the housing. Instead of relying on a single horizontal annular chamber, sand particles are collected at multiple vertical levels. This dimensional approach ensures that particles settling at different rates and positions are all captured, preventing them from reaching the pump.
2Ease of operation
If sand settles back on top of the pump when the system is shut down, then sand fills upper stages creating frictional force, but the pump cannot overcome the blockage and eventually burns out
Solution Approach 1:
The device performs preliminary sand collection during normal operation and maintains collected sand on the shelves during shutdown periods. The restrictor assembly maintains a pressure differential that prevents settled sand from migrating to the pump even when fluid flow stops. This preliminary containment action ensures the pump starts clean after shutdown without needing to overcome sand blockages.
Solution Approach 2:
The restrictor assembly creates a protective pressure barrier beforehand that cushions against sand migration. By maintaining pressure differential across the shelves during both operation and shutdown, the system preemptively prevents sand from reaching the pump, cushioning the pump against the harmful effects of sand accumulation before they can occur.
3Reliability
If conventional devices allow fluid flow in both directions, then fluid can be flushed through the system, but sand can also enter or block the ESP from external conditions
Solution Approach 1:
The restrictor assembly dynamically adjusts flow resistance based on pressure differential. During normal production, it allows efficient fluid flow through the housing. During shutdown or reverse pressure conditions, it automatically restricts flow to prevent sand migration. This dynamic response maintains productivity during operation while protecting against sand intrusion during adverse conditions.
Solution Approach 2:
The restrictor assembly acts as an intermediary flow control mechanism between the sand collection chamber and the pump. It mediates between the need for fluid flow and the need for sand exclusion by selectively allowing or restricting flow based on pressure conditions, protecting the pump from sand while maintaining fluid productivity.
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
The tool effectively prevents sand from settling on the pump, allowing for efficient fluid flow and easy removal of collected sand, reducing the risk of pump failure and associated costs by maintaining a single flow path and using a restriction mechanism to manage fluid flow and debris.
Implementation Method 1
A restrictor assembly can be disposed at one end of the housing and configured to allow fluid flow through the housing in one direction and at least partially restrict flow through the housing in an opposite, second direction
Implementation Method 2
each shelf provides a surface for supporting and collecting sand or other solids within the housing
Data Source
AI summary
Device and method for protecting a submersible pump. The device can include a housing for connecting to a downhole pump, and a plurality of shelves disposed throughout the housing, wherein at least two shelves are axially spaced from one another, and each shelf provides a surface for supporting and collecting sand or other solids within the housing. A restrictor assembly can be disposed at one end of the housing and configured to allow fluid flow through the housing in one direction and at least partially restrict flow through the housing in an opposite, second direction.