Labyrinth ESP Protector for Compact Motor Ingress Control
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Solution Overview
Problem
Existing electric submersible pump (ESP) protectors are costly to manufacture and require lengthy designs, posing a risk of well fluid ingress into the motor due to pressure differentials, which can cause electrical shorts and mechanical damage.
Innovation Solution
A protector with a pressure-resistant housing and a mandrel featuring a labyrinth tube made of elastomer or corrugated metal wound around the mandrel, creating a tortuous path to minimize well fluid ingress while maintaining pressure equalization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional labyrinth protector is used to prevent well fluid ingress, then motor protection is improved, but manufacturing cost and device length increase
Solution Approach 1:
The protector is divided into distinct functional components: a pressure-resistant housing, a mandrel with fluid port, and a labyrinth tube. This segmentation allows each component to be optimized independently and manufactured separately, reducing overall complexity while maintaining protection functionality.
Solution Approach 2:
The labyrinth tube creates a tortuous three-dimensional fluid path that winds around the mandrel multiple times. This dimensional approach to fluid routing provides effective protection through increased flow path length and complexity without requiring the entire protector assembly to be longer, as the tortuous path is achieved through radial and axial winding patterns within a compact volume.
2Duration of action of stationary object
If pressure equalization is maintained to prevent seal failure, then seal life is improved, but risk of well fluid leakage into motor increases
Solution Approach 1:
The labyrinth tube acts as an intermediary barrier between the well fluid and the motor. It allows pressure equalization to protect seals while simultaneously providing a tortuous path that impedes fluid migration. The fluid port in the mandrel serves as a controlled intermediary point that manages pressure communication while maintaining fluid separation.
Solution Approach 2:
The pressure differential that could potentially force well fluid through seals is converted into a beneficial force by the labyrinth structure. The tortuous path transforms the direct pressure threat into a slowed, redirected fluid flow that must navigate complex geometry, converting the harmful pressure differential into a mechanism that further impedes fluid ingress while maintaining necessary pressure balance.
3Reliability
If a tortuous fluid path is created to slow fluid migration, then fluid ingress is reduced, but device complexity and length increase
Solution Approach 1:
The tortuous fluid path is achieved by winding the labyrinth tube around the mandrel in a three-dimensional configuration. This allows the fluid to traverse a long, complex path radially and axially within a compact axial length. The protector achieves extended fluid path length without proportionally increasing overall device length by utilizing radial spacing and multiple winding turns around the central mandrel.
Solution Approach 2:
The labyrinth tube is nested around the central mandrel, with the fluid path winding through the annular space between the mandrel surface and the tube. This nested configuration maximizes the fluid path length within the available radial and axial space, creating an effective tortuous path without requiring excessive overall dimensions.
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 solution effectively reduces the risk of well fluid entering the motor by providing a cost-effective, compact design that maintains pressure equalization, thus prolonging seal life and preventing electrical and mechanical damage.
Implementation Method 1
A protector may have a tortuous fluid path that slows down the migration of well fluid through the protector to reduce the chance of well fluid entering the drivetrain through any leak in the pressure compensating device or mechanical seal
Implementation Method 2
the protector contains a pressure compensation device to act as a barrier to well fluid entering the drive train part of the ESP (i.e., components proximate to and including the motor) while still transmitting the pressure from the well fluid to the drive train
Implementation Method 3
a mandrel sealingly engaged with an interior of the housing to define a fluid tight chamber in an annular space between the housing and the mandrel
Data Source
AI summary
A protector for an electric submersible pump system has a pressure resistant housing and a mandrel sealingly engaged with an interior of the housing to define a fluid tight chamber in an annular space between the housing and the mandrel. The mandrel has a fluid port at one longitudinal end. A labyrinth tube is in sealed fluid communication with the fluid port, and is wound around the mandrel to longitudinally traverse the mandrel toward another longitudinal end thereof and back toward the fluid port. An end of the labyrinth tube is fluidly exposed in the fluid tight chamber.