Corrosion-Resistant Bearing Elements for Drilling Fluid Exposure
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Solution Overview
Problem
Subterranean drilling systems face challenges with the operational lifetime of thrust-bearing apparatuses due to corrosion from drilling fluids, which affect the overall performance and longevity of the drilling process.
Innovation Solution
The implementation of bearing assemblies with corrosion-resistant properties, featuring polycrystalline diamond tables and substrates, along with corrosion-resistant regions and sacrificial anodes, to protect the bearing elements from galvanic and electrochemical corrosion when exposed to lubrication or cooling fluids.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If bearing elements are made from polycrystalline diamond compacts with metal-solvent catalysts, then bearing performance and torque generation are improved, but corrosion resistance deteriorates when exposed to drilling fluids
Solution Approach 1:
The patent applies local quality by creating a corrosion-resistant coating on specific surfaces of the bearing elements that are exposed to drilling fluids, while maintaining the metal-solvent catalyst composition in the bulk material for optimal bearing performance. The coating is selectively applied to lateral surfaces and bonding regions where corrosion occurs, preserving the functional properties where needed.
Solution Approach 2:
The patent uses composite materials by combining a metal-solvent catalyst-based polycrystalline diamond compact with a corrosion-resistant coating layer. This creates a multi-layer structure where the inner layer provides bearing performance through metal bonding and the outer layer provides corrosion resistance, effectively resolving the contradiction between performance and corrosion resistance.
2Productivity
If drilling fluid is circulated through the drill string to generate torque, then drilling efficiency is improved, but corrosion of bearing elements occurs due to fluid exposure
Solution Approach 1:
The patent introduces a corrosion-resistant coating as an intermediary layer between the drilling fluid and the bearing element surfaces. This coating acts as a mediator that allows the drilling fluid to perform its lubrication and cooling functions while preventing direct contact with and corrosion of the metal-solvent catalyst material, thereby maintaining both drilling efficiency and operational lifetime.
Solution Approach 2:
The patent applies a relatively thin corrosion-resistant coating that can be applied cost-effectively to bearing elements. This coating serves as a sacrificial or protective layer that extends the operational lifetime of the bearing elements without significantly increasing cost, allowing the system to withstand the corrosive environment of circulating drilling fluids.
3Strength
If metal-solvent catalysts are used in the polycrystalline diamond table, then bonding strength is improved, but susceptibility to galvanic and electrochemical corrosion increases
Solution Approach 1:
The patent applies local quality by restricting metal-solvent catalysts to specific regions where bonding is required (such as the bonding region between diamond grains and substrate) while applying corrosion-resistant coatings to surfaces exposed to drilling fluids. This spatial differentiation allows bonding strength to be maximized where needed while corrosion resistance is provided where exposure occurs.
Solution Approach 2:
The patent creates a composite structure where the metal-solvent catalyst phase provides bonding strength internally, while an external corrosion-resistant coating phase protects the metal-containing regions from galvanic and electrochemical corrosion. This composite approach allows both bonding strength and corrosion resistance to coexist.
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
Enhances the operational lifetime of thrust-bearing apparatuses by preventing corrosion, thereby extending the useful life of subterranean drilling systems and improving drilling efficiency.
Implementation Method 1
protect the bearing elements from leaching, galvanic, or electrochemical corrosion that may occur when the bearing assembly comes in contact with lubrication or cooling fluid
Implementation Method 2
protect the bearing elements from leaching, galvanic, or electrochemical corrosion that may occur when the bearing assembly comes in contact with lubrication or cooling fluid
Implementation Method 3
bearing assemblies, bearing apparatuses, motors, pumps, or other mechanical assemblies that include bearing elements or support rings having corrosion resistant properties configured to protect the bearing elements from leaching, galvanic, or electrochemical corrosion
Data Source
AI summary
Embodiments disclosed herein relate to bearing assemblies and methods of manufacturing. In an embodiment, a bearing assembly includes a support ring and bearing elements. The bearing elements are mounted to and distributed circumferentially about an axis of the support ring. At least one of the bearing elements includes a polycrystalline diamond table, a substrate bonded to the polycrystalline diamond table, bonding region defined by the substrate and the polycrystalline diamond table, and a corrosion resistant region. The corrosion resistant region includes a corrosion resistant material that covers at least a portion of at least one lateral surface of the bonding region. The corrosion resistant region prevents corrosion of at least some material in the bonding region covered by the corrosion resistant region (e.g., during use). Other embodiments employ one or more sacrificial anodes as an alternative to or in combination with the corrosion resistant region.