Heavy-Metal-Free Pipe Dope for HPHT Sealing and Anti-Galling
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Solution Overview
Problem
Current pipe dopes for high-pressure/high-temperature (HPHT) wells contain heavy metals and sulfur, posing environmental hazards and failing at temperatures above 150°C due to evaporation or thermal degradation, leading to leakage and loss of lubricity.
Innovation Solution
A lubricant composition comprising a base oil, an organophilic clay-based thickener, and a solid lubricant (natural or synthetic graphite) without heavy metals, along with group 2 metal-based inorganic compounds, which forms a stable film to maintain sealing performance under HPHT conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional pipe dope containing heavy metals and sulfur is used for HPHT applications, then sealing performance and anti-galling properties are improved, but environmental hazards increase and the dope fails at temperatures above 150°C due to evaporation and thermal degradation
Solution Approach 1:
The invention removes harmful heavy metals (lead, zinc, copper) and sulfur from the pipe dope formulation, extracting the toxic components while retaining the essential lubricating and sealing functions through alternative ingredients such as calcium-based additives and graphite
Solution Approach 2:
The invention changes the chemical composition parameters by substituting heavy metal-based extreme pressure additives with calcium-based inorganic compounds and organic additives, thereby maintaining anti-galling performance while eliminating environmental hazards and improving thermal stability above 150°C
2Reliability
If conventional pipe dope is used to ensure sealing and lubrication, then joint integrity is maintained, but the dope evaporates or degrades thermally at temperatures over 150°C, leading to leakage and loss of lubricity
Solution Approach 1:
The invention creates a composite lubricant formulation combining base oil with specific proportions of calcium-based inorganic compounds (such as calcium carbonate, calcium sulfate, calcium phosphate), organic additives, and solid lubricants like graphite, where each component contributes to thermal stability and the synergistic combination prevents degradation at temperatures above 150°C
Solution Approach 2:
The invention replaces expensive and unstable heavy metal compounds with more stable, cost-effective calcium-based inorganic materials that maintain their structural integrity and lubricating properties under high temperature conditions, ensuring long-term joint integrity
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 lubricant composition provides effective anti-galling and sealing performance without heavy metals, reducing environmental impact and maintaining lubricity even at elevated temperatures, outperforming existing dopes in stability and friction behavior.
Implementation Method 1
the solid lubricant is present in an amount in the range of from 5 to 30wt% based on the overall weight of the lubricant composition and is selected from natural and synthetic graphite
Implementation Method 2
an organophilic, clay-based thickener
Implementation Method 3
wherein the lubricant composition also comprises one or more group 2 metal based inorganic compounds
Data Source
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AI summary
The present invention provides a lubricant composition comprising: (i) a base oil (ii) an organophilic clay-based thickener; and (iii) a solid lubricant, wherein said solid lubricant does not comprise any heavy metals. The present invention also provides the use of a lubricant composition comprising: a base oil; an organophilic clay-based thickener; and a solid lubricant, wherein said solid lubricant does not comprise any heavy metals, as a pipe dope.