Downhole Bearing Lubrication Flow Control for Low-Windage Rotation
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Solution Overview
Problem
Downhole-type rotating machines in wells face challenges with lubrication systems, particularly at higher speeds, where flooded approaches lead to high windage losses and seal wear, resulting in reduced efficiency and increased capital costs.
Innovation Solution
A lubrication system is implemented with a topside pressure pump and a distribution manifold that provides adjustable lubrication to bearings via flow restrictions, allowing for customized lubrication rates and the use of well treatment chemicals, which minimizes leakage and contamination, and enables higher operating speeds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a flooded lubrication approach is used in downhole-type rotating machines, then lubrication is provided to bearings, but windage losses increase and seal wear increases at higher speeds
Solution Approach 1:
The patent extracts the lubrication function from a flooded approach and implements a targeted delivery system using a distribution manifold with flow restrictions that supply lubrication only where needed to specific bearings, eliminating the energy losses associated with flooding the entire downhole environment
Solution Approach 2:
The patent introduces a distribution manifold with flow restrictions as an intermediary device between the lubrication source and the bearings. This intermediary enables precise control of lubrication delivery, providing adequate lubrication while minimizing windage losses by avoiding unnecessary lubrication in non-bearing areas
2Reliability
If a flooded lubrication approach is used in downhole-type rotating machines, then lubrication is provided to bearings, but seal wear increases
Solution Approach 1:
The patent extracts the lubrication function from a flooded approach and implements a targeted delivery system using a distribution manifold with flow restrictions that supply lubrication only where needed to specific bearings, eliminating the harmful effects of lubrication flooding on seals
Solution Approach 2:
The patent applies local quality by delivering lubrication specifically to bearing locations rather than flooding the entire downhole environment. The distribution manifold with flow restrictions ensures lubrication is applied locally at bearing interfaces, preventing seal exposure to excessive lubrication that causes wear
3Reliability
If fixed downhole lubrication reservoirs are used, then lubrication is provided to bearings, but capital costs increase
Solution Approach 1:
The patent extracts the lubrication delivery function from complex fixed downhole reservoirs and implements a simpler distribution manifold system with flow restrictions that can be integrated into existing lubrication lines, reducing capital costs while maintaining reliable bearing lubrication
Solution Approach 2:
The distribution manifold with flow restrictions serves multiple functions: it distributes lubrication to multiple bearings, controls flow rates to each bearing, and can be integrated with existing lubrication systems. This multi-functionality eliminates the need for separate fixed reservoirs at each bearing location, reducing overall system complexity and capital costs
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
This solution enhances the reliability and performance of downhole-type rotating machines by reducing windage losses, eliminating the need for fixed downhole lubrication reservoirs, and allowing for customization across various operating conditions, thereby increasing well production and reducing capital costs over time.
Implementation Method 1
A lubrication system is fluidically coupled to the downhole-type device. The lubrication system includes a topside pressure pump. A downhole-type distribution manifold is within a wellbore. The distribution manifold fluidically connects to the topside pressure pump, the first bearing, and the second bearing.
Implementation Method 2
The distribution manifold includes a first flow restriction between the topside pressure pump and the first bearing, and a second flow restriction, different from the first flow restriction, between the topside pressure pump and the second bearing.
Data Source
AI summary
A downhole-type device includes a fluid-end with a fluid rotor configured to move or be rotated by wellbore fluids. A fluid stator surrounds and supports the fluid rotor. A first bearing couples the fluid rotor to the fluid stator. A second bearing couples the fluid rotor to the fluid stator. An electric machine includes an electrical rotor rotably coupled to the fluid rotor. The electric rotor is configured to rotate in unison with the fluid rotor. An electrical stator surrounds and supports the electric rotor. A lubrication system is fluidically coupled to the downhole-type device. The lubrication system includes a topside pressure pump. A downhole-type distribution manifold is within a wellbore. The distribution manifold fluidically connects to the topside pressure pump, the first bearing, and the second bearing.