Polyurethane-Polyurea Coating for Threaded Tubular Components
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Solution Overview
Problem
Threaded tubular components used in drilling and working hydrocarbon wells face issues with galling and corrosion due to harsh environmental conditions, and existing lubricants, such as API-standard greases, are not environmentally friendly and require frequent application.
Innovation Solution
A dry film coating with a polyurethane and polyurea matrix, where urethane functionality predominates, providing high mechanical strength, low friction, and resistance to wear, corrosion, and galling, applied to the threaded zones and sealing surfaces, which can be adapted to various metal grades and applied during manufacturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If API-standard greases are used for lubrication, then friction is reduced during makeup operations, but environmental pollution increases due to heavy metal release
Solution Approach 1:
The invention changes the chemical composition parameters of the lubricant by using a polyurethane-polyurea matrix with specific urethane functionality (≥55% by weight) instead of traditional grease formulations containing heavy metals. This parameter change maintains lubrication effectiveness while eliminating environmental pollution.
Solution Approach 2:
The invention uses a composite coating material combining polyurethane and polyurea in a specific ratio (urethane functionality ≥55% by weight). This composite material provides both lubrication properties and environmental compatibility, resolving the contradiction between friction reduction and pollution prevention.
2Reliability
If solid dry coatings are applied to threaded zones, then resistance to galling and corrosion is improved, but manufacturing complexity increases
Solution Approach 1:
The invention optimizes the chemical composition parameters of the coating material by specifying a polyurethane-polyurea matrix with urethane functionality of at least 55% by weight. This parameter optimization ensures adequate cure rate and film formation while simplifying the manufacturing process compared to more complex coating systems.
3Force
If traditional lubricants are applied on site for each makeup operation, then lubrication is maintained, but time consumption and operational complexity increase
Solution Approach 1:
The invention applies the lubricating coating as a permanent factory-applied layer on the threaded components before they reach the well site. This preliminary action eliminates the need for repeated on-site lubricant application during makeup operations, saving time and reducing operational complexity while maintaining continuous lubrication protection.
4Strength
If a coating with high urethane functionality is used, then mechanical strength and wear resistance are improved, but curing time may increase
Solution Approach 1:
The invention optimizes the chemical composition by specifying a balanced formulation with urethane functionality of at least 55% by weight (but not exceeding 100%). This parameter optimization achieves the right balance between mechanical strength/wear resistance and acceptable curing time, preventing excessive curing delays while ensuring adequate coating performance.
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 coating offers long-term resistance to galling and corrosion, reduces friction, and maintains performance under extreme conditions, eliminating the need for frequent site applications and minimizing environmental impact.
Implementation Method 1
coatings which are inert as regards the environment and which are resistant to wear and to atmospheric and climatic conditions are being developed
Implementation Method 2
it is necessary to use coatings that counter corrosion, on the surfaces which have to cooperate by makeup (threaded zones) or by interfering contact (metal/metal sealing surfaces)
Implementation Method 3
which induces risks of galling at the threaded zones and at the metal/metal sealing surfaces
Data Source
AI summary
The invention concerns a threaded tubular component for drilling or working hydrocarbon wells, said tubular component having at one of its ends (1; 2) a threaded zone (3; 4) produced on its outer or inner peripheral surface depending on whether the threaded end is male or female in type, in which at least a portion of the end (1; 2) is coated with at least one film of polyurethane (12), 100% solid state, with an essentially rigid structure, based on a matrix of polyurethane and polyurea, in which the urethane functionality is predominant with respect to the urea functionality in a proportion of at least 55% by weight.