Oil Well Thread Coating Composition for Galling-Resistant Joints
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Solution Overview
Problem
Existing lubrication technologies for oil country tubular goods using solid lubricating coating films fail to simulate the large and unbalanced loads experienced in actual well conditions, leading to optimistic evaluations and inadequate design of the solid lubricating coating films, which are prone to damage and fail to provide effective lubrication and corrosion resistance under real-world conditions.
Innovation Solution
A solid lubricating coating film is developed using a binder resin containing nitrocellulose and alkyd resin with melamine cyanurate as the main solid lubricant, optimized to withstand large and unbalanced loads, with specific particle size and composition ranges to ensure effective lubrication and corrosion resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional solid lubricating coating film is used without optimization for actual well conditions, then the evaluation results are optimistic, but the coating film is prone to damage under large and unbalanced loads
Solution Approach 1:
The patent optimizes the composition parameters of the binder resin (nitrocellulose and alkyd resin ratios) and solid lubricant (MCA particle size and content) to achieve a coating film that can withstand large and unbalanced loads while maintaining lubrication performance. This parameter optimization resolves the contradiction between evaluation accuracy and coating reliability.
Solution Approach 2:
The patent uses a composite binder resin system combining nitrocellulose and alkyd resin, along with melamine cyanurate as solid lubricant, to create a coating film with enhanced mechanical properties and lubrication performance. The composite material approach allows the coating to maintain integrity under load while providing effective lubrication.
2Ease of operation
If the solid lubricating coating film is optimized for lubrication, then lubricity is improved, but corrosion resistance may be compromised
Solution Approach 1:
The patent develops a multi-functional coating film that simultaneously provides lubrication, corrosion resistance, and mechanical durability. The binder resin system and solid lubricant combination is designed to perform multiple functions, resolving the contradiction between lubrication performance and corrosion protection.
3Ease of manufacture
If a simple coating formulation is used, then manufacturing is easier, but the coating cannot withstand actual well conditions
Solution Approach 1:
The patent optimizes the formulation parameters including the ratios of nitrocellulose to alkyd resin, MCA particle size distribution, and solid lubricant content to achieve the right balance between manufacturability and coating strength. The optimized formulation maintains ease of application while providing the required mechanical strength.
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 optimized solid lubricating coating film provides enhanced lubricity and corrosion resistance, matching the demands of actual well conditions, ensuring reliable performance and reducing the risk of seizure during make-up and break-out operations.
Implementation Method 1
a solid lubricating coating film is formed on a tightening surface (including a metal sealing surface) of a thread portion instead of a wet lubricating compound
Implementation Method 2
a solid lubricating coating film is formed on a tightening surface... including a binder resin as a matrix component, a solid lubricant dispersed and distributed in the binder resin
Data Source
Figure 1
Figure 2A~2B
Figure 3A~3B
AI summary
The present disclosure realizes seizure resistance (galling resistance) equal to or higher than that of a dope compound method of the prior art in terms of lubrication properties during make-up and break-out of oil country tubular goods by using a solid lubricating coating film. An agent for forming a solid lubricating coating film on a tightening surface of a thread portion, in which a solid lubricant is dispersed in a binder resin as a matrix component, a main component of the solid lubricant is melamine cyanurate, and an average particle diameter of the melamine cyanurate is 0.1 um or more and 10.0 um or less, the binder resin contains an alkyd resin and nitrocellulose, and the alkyd resin and nitrocellulose are contained in an amount of 85 wt% or more of the total binder resin component weight, and a total weight of the solid lubricant is 10 parts by weight or more and 100 parts by weight or less based on 100 parts by weight of a total weight of the binder resin.