Threaded Tubular Coating for Hydrocarbon Well Connections
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Solution Overview
Problem
Threaded tubular components used in drilling and working hydrocarbon wells face challenges in achieving optimal mechanical strength and sealing performance due to limitations in galling resistance and corrosion resistance, particularly under high-pressure and corrosive conditions, which affect the interference fit and longevity of connections.
Innovation Solution
A dry film coating with an organic matrix containing ion exchange pigments, such as calcium ion exchange silica, is applied to the threaded zones and sealing surfaces, providing enhanced shear strength, torque resistance, and corrosion protection, thereby improving the galling resistance and mechanical integrity of the connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional normalized lubricants are used, then the coating process is simple, but the difference between plastification torque and shouldering torque is insufficient
Solution Approach 1:
The patent employs a composite coating system consisting of an organic matrix combined with ion exchange pigments (such as zinc phosphate, calcium carbonate, or magnesium hydroxide). This composite structure provides both the mechanical properties needed for torque resistance and the chemical properties for corrosion protection, thereby achieving the required difference between plastification torque and shouldering torque while maintaining a manageable coating process
Solution Approach 2:
The patent modifies the coating parameters by incorporating ion exchange pigments with specific chemical compositions and particle size distributions. These parameter changes enhance the coating's ability to resist galling and provide corrosion protection, resulting in improved torque characteristics without excessive complexity in the coating application process
2Reliability
If high-pressure shear strength is increased to prevent galling, then galling resistance improves, but the coating may fail under severe corrosion conditions
Solution Approach 1:
The patent changes the chemical composition parameters of the coating by incorporating ion exchange pigments that provide both mechanical strength for galling resistance and chemical stability for corrosion resistance. The specific ratios and types of pigments are optimized to maintain high-pressure shear strength while protecting against corrosive environments
Solution Approach 2:
The composite coating system combines an organic matrix with ion exchange pigments to create a material that simultaneously provides galling resistance through high-pressure shear strength and corrosion resistance through the chemical stability of the pigment components. This dual-function composite addresses both reliability concerns in severe service conditions
3Reliability
If makeup torque is increased to ensure correct positioning and sealing, then sealing performance improves, but plastification of abutments occurs
Solution Approach 1:
The patent introduces a coating layer as an intermediary between the male and female threaded components. This coating acts as a mediator that reduces friction and allows for correct positioning and sealing at lower makeup torques, preventing plastification of the abutments while maintaining reliable sealing performance
Solution Approach 2:
The patent replaces the direct metal-to-metal contact mechanism with a coated surface interaction. The coating layer substitutes for the purely mechanical interference fit, allowing for controlled slip and positioning that achieves sealing without excessive force that would cause abutment plastification
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 significantly increases the torque resistance and corrosion protection, allowing for multiple makeup and breakout cycles without surface alteration, and extends the connection's lifespan by resisting corrosion and ensuring a strong, reliable seal under severe service conditions.
Implementation Method 1
a dry film comprising an organic matrix in which ion exchange pigments are dispersed
Implementation Method 2
The coating significantly increases the torque resistance and corrosion protection, allowing for multiple makeup and breakout cycles without surface alteration
Data Source
AI summary
A threaded end (1; 2) of a tubular component for drilling or working hydrocarbon wells, said end comprising a threaded zone (3; 4) produced on its external or internal peripheral surface depending on whether the threaded end is male or female in type, at least a portion of the end (1; 2) being coated with a dry film comprising an organic matrix in which ion exchange pigments are dispersed in proportions in the range 3% to 30% by weight; and a connection resulting from connecting two corresponding ends by makeup.