Graphite-Dispersed Well Cement Slurry for Higher Heat Conductivity
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Solution Overview
Problem
Existing well-cementing materials used in geothermal wells have low heat conductivity, and adding excessive graphite to improve conductivity can compromise the strength and performance of the cement, leading to reduced service life and engineering issues.
Innovation Solution
A method involving the use of an admixture of sodium 1-butanesulfonate, sodium dodecyl diphenyl ether disulfonate, and polyvinylpyrrolidone to modify graphite dispersion, which is then added to cement slurry to enhance its dispersibility and thermal conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If graphite is added to improve heat conductivity, then heat conductivity coefficient is improved, but strength of well-cementing materials deteriorates
Solution Approach 1:
The patent introduces a dispersant as an intermediary substance that mediates between graphite particles and cement slurry. The dispersant wraps around graphite particles, preventing aggregation and ensuring uniform distribution, thereby maintaining both high heat conductivity and structural strength of the cement material.
Solution Approach 2:
The patent creates a composite material system consisting of graphite particles, dispersant, and cement slurry. This composite structure allows the graphite to provide thermal conductivity while the dispersant-cement matrix maintains mechanical strength, resolving the contradiction between thermal and mechanical properties.
2Temperature
If amount of graphite is increased to improve heat conductivity, then heat conductivity coefficient is improved, but slurry performances deteriorate
Solution Approach 1:
The dispersant acts as a mediator that enables high graphite content to be incorporated without compromising slurry performance. It reduces friction between graphite particles, improves fluidity, and prevents sedimentation, allowing the slurry to maintain good working properties even with increased graphite concentration.
Solution Approach 2:
The patent changes the physical-chemical parameters of the slurry by introducing the dispersant, which modifies surface tension, viscosity, and particle interaction forces. These parameter changes allow the slurry to maintain optimal flow and placement characteristics despite high graphite content.
3Temperature
If amount of graphite is increased to improve heat conductivity, then heat conductivity coefficient is improved, but interface cementation between graphite and cement materials deteriorates
Solution Approach 1:
The dispersant serves as an intermediary at the interface between graphite and cement, forming a bonding layer that enhances adhesion. This interface modification ensures strong cementation between graphite particles and cement matrix, preventing delamination and ensuring reliable thermal contact.
Solution Approach 2:
The dispersant changes the surface properties of graphite particles, making them more compatible with the cement matrix. This surface modification improves wettability, adhesion, and chemical bonding at the interface, thereby enhancing the reliability of interface cementation.
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 method results in a heat-conductive cement slurry with improved thermal conductivity and strength, suitable for both oil and geothermal wells, while maintaining the structural integrity and performance of the cement.
Implementation Method 1
Graphite is modified by adding an admixture compounded by sodium 1-butanesulfonate, sodium dodecyl diphenyl ether disulfonate and polyvinylpyrrolidone, and then a graphite dispersion is added to cement slurry
Implementation Method 2
sodium 1-butanesulfonate, sodium dodecyl diphenyl ether disulfonate and polyvinylpyrrolidone to obtain an admixture; dissolving the admixture in deionized water and stirring to obtain a dispersant solution
Implementation Method 3
The high heat conductivity of graphite can play a dominant role and effectively improve the heat conductivity coefficient of set cement, and significantly improve the heat conductivity of the set cement
Data Source
AI summary
A method for preparing heat-conductive cement slurry for well cementation includes the following steps: S1, uniformly mixing sodium 1-butanesulfonate, sodium dodecyl diphenyl ether disulfonate and polyvinylpyrrolidone to obtain an admixture; S2, dissolving the admixture in deionized water and stirring to obtain a dispersant solution; S3, adding graphite to the dispersant solution and stirring to obtain a graphite dispersion; S4, stirring cement and deionized water in a slurry cup to obtain cement slurry; and S5, mixing and stirring the graphite dispersion and the cement slurry to obtain the heat-conductive cement slurry. The heat-conductive cement slurry can effectively improve the heat conductivity coefficient of set cement, and significantly improve the heat conductivity of the set cement, and has a broad market application prospect.