Oil Well Threaded Joint Coating for Uniform Corrosion Protection

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Solution Overview

Problem

Existing methods for coating oil well pipe components, particularly threaded portions, often result in non-uniform layer thickness, leading to issues with corrosion and galling, and involve the use of volatile organic solvents, which are environmentally unfriendly.

Innovation Solution

The use of cataphoresis from an aqueous bath to deposit a corrosion-inhibiting material onto oil well pipe components, ensuring a uniform layer thickness and reducing environmental impact.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional coating methods (spraying, dipping, brushing) are used to apply corrosion-inhibiting material, then the coating process is simple and fast, but the layer thickness becomes non-uniform leading to galling and corrosion issues

Engineering Contradiction:

Improvelayer thickness uniformityVSAvoidcoating process complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent replaces mechanical coating methods (spraying, dipping, brushing) with an electrochemical deposition process. The corrosion-inhibiting material is applied through electrochemical reactions where metal ions are reduced and deposited onto the threaded surfaces, ensuring uniform layer thickness without the variability inherent in mechanical application methods.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the fundamental parameter of the coating process from mechanical force-based application to electrochemical potential-based deposition. By controlling electrical parameters (current density, voltage, electrolyte composition), the process achieves precise control over layer thickness and uniformity that cannot be obtained through conventional mechanical methods.

Inventive Principle:

Principle #35Parameter changes

2Productivity

If conventional coating methods are used, then application is straightforward, but volatile organic solvents are required which are environmentally unfriendly

Engineering Contradiction:

Improvecoating application efficiencyVSAvoidenvironmental pollution from organic solvents

Core Design Contradiction:

ProductivityVSObject-generated harmful factors

Solution Approach 1:

The patent changes the solvent parameter from volatile organic compounds to aqueous electrolyte solutions. The electrochemical deposition process uses water-based electrolytes containing metal salts and conductive agents, eliminating the need for volatile organic solvents while maintaining efficient coating application through electrical current driving the deposition reaction.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If non-uniform coatings are applied to threaded portions, then application process is simpler, but friction increases causing torque fluctuations and connection reliability issues

Engineering Contradiction:

Improveconnection reliabilityVSAvoidcoating application simplicity

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent replaces simple mechanical coating application with an electrochemical deposition system that inherently produces uniform coatings. The electrical field distributes the corrosion-inhibiting material evenly across the threaded surfaces through ionic conduction and electrochemical reduction, ensuring consistent friction characteristics and reliable torque values without requiring complex manual application techniques.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 method provides a uniform corrosion-inhibiting layer with minimal variance, effectively preventing corrosion and galling while being environmentally friendly, and enhances the airtightness of threaded joints under harsh conditions.

Implementation Method 1

at least part of the threaded portion is coated with a layer of a corrosion-inhibiting material, that has been applied to at least the part of the threaded portion of the oil well pipe component by means of cataphoresis from an aqueous bath

Methodology Applied

Scientific EffectCataphoresis: Electrophoretic Deposition

Data Source

PatentUS11359303B2Threaded joint for an oil well pipe

Publication Date: 2022.06.14 TENARIS CONNECTIONS BV

AI summary

Oil well pipe component comprising a threaded portion, at least part whereof is coated with a layer of a corrosion-inhibiting material, that has been applied to at least the part of the threaded portion of the oil well pipe component by means of a method comprising a cataphoresis step from an aqueous bath, said method comprisingproviding the oil well pipe component comprising a threaded portion;immersing at least part of the threaded portion of the pipe component in a cataphoresis bath comprising water and suspended particles of corrosion-inhibiting material, and provided with an anode and a cathode means, the pipe component being connected to the cathode means;inducing a current through the bath, in order to provide the corrosion-inhibiting material with a positive charge;depositing a layer of the positively charged corrosion-inhibiting material onto the pipe component; andremoving the immersed part of the pipe component with the layer of corrosion-inhibiting material from the cataphoresis bath and allowing the corrosion-inhibiting material to set.