Downhole Blower System with Labyrinth Seals and Segmented Stator
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Solution Overview
Problem
Well production declines as reservoir pressures decrease, making it difficult for gas wells to maintain production without external assistance, as natural pressures are insufficient to push fluids to the surface.
Innovation Solution
A downhole blower system is installed in the wellbore, comprising a segmented fluid stator with a rotor and bearing assemblies, sealed with labyrinth seals containing grease for lubrication and sealing, and an electric machine driven by a variable frequency drive to enhance pressure and flow rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a downhole blower system is installed to increase gas flow and pressure, then well production is extended and optimized, but the complexity of the device increases with multiple bearing assemblies and seals required to withstand downhole conditions
Solution Approach 1:
The blower system is divided into multiple axially stacked stator segments that are clamped together to form the complete stator. This segmentation allows for easier assembly and disassembly of the downhole blower system while maintaining the required structural integrity and performance characteristics for withstanding downhole pressures and temperatures
Solution Approach 2:
Multiple bearing assemblies are nested axially along the rotor shaft, with each bearing assembly containing lubricated seals nested within them. This nested arrangement allows multiple functional components to be integrated in a compact configuration, reducing overall device complexity while maintaining necessary separation and protection functions
2Reliability
If multiple seals are used to protect bearing assemblies from the downhole environment, then reliability is improved, but the device complexity increases with multiple labyrinth seals and grease packing
Solution Approach 1:
Lubricated seals are employed that utilize grease packing to automatically lubricate themselves and maintain sealing effectiveness without requiring external lubrication systems. The grease is contained within the labyrinth seal structure, creating a self-sustaining lubrication and sealing system that maintains reliability throughout the downhole operational period
Solution Approach 2:
Labyrinth seals act as intermediary structures between the bearing assemblies and the harsh downhole environment. These seals create a protective barrier that mediates the interaction between the sensitive bearing components and the high-pressure, high-temperature wellbore conditions, allowing reliable operation without direct exposure to environmental extremes
3Duration of action of stationary object
If bearing assemblies are sealed from the downhole environment, then durability is improved, but maintenance difficulty increases due to the sealed configuration
Solution Approach 1:
The stator is segmented into multiple axially stacked segments that can be independently handled and reassembled. This segmentation allows the bearing assemblies to be accessed and maintained by disassembling the stator segments, making maintenance more feasible despite the sealed configuration, thereby maintaining durability while improving ease of repair
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 system creates a pressure differential within the wellbore, increasing gas flow to the surface by boosting pressure and reducing condensation, thereby extending the life of the well and optimizing production.
Implementation Method 1
The plurality of seals can each include a labyrinth seal. The labyrinth seal can include a grease packed within a gap in the labyrinth seal. The grease is capable of maintaining its lubrication and sealing properties in a downhole environment.
Implementation Method 2
An electric machine is positioned downhole of and coupled to the blower. The electric machine can drive the blower. The electric machine and the blower can be coupled by a single shaft extending through the electric machine and the blower.
Implementation Method 3
The electric machine includes an electric machine stator arranged to form an annulus with an inner wall of the wellbore. The annulus is configured to flow a gas therethrough to cool the electric machine during operation of the downhole-type blower.
Data Source
AI summary
This disclosure describes various implementations of a downhole-blower system that can be used to boost production in a wellbore. The downhole-blower system includes a blower and an electric machine coupled to the blower that can be deployed in a wellbore, and that can, in cooperation, increase production through the wellbore.