Cement Composition with Hollow Elements for CO2 Sequestration
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional Portland cement systems used in well cementation are unstable in CO2-rich environments, leading to degradation and loss of zonal isolation in CO2 sequestration wells, as they react with carbon dioxide, reducing compressive strength and increasing permeability, which poses a challenge for long-term environmental safety and efficient storage of carbon dioxide.
Innovation Solution
A cement composition incorporating hollow elements such as cenospheres or sodium-calcium-borosilicate glass microspheres, or a metakaolin-based or blast furnace slag-based cement slurry with optimized particle sizes and proportions to enhance chemical stability and durability in supercritical CO2 conditions, along with a method for applying and hardening the cement in CO2-exposed borehole sections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional Portland cement is used for well cementation, then the cement provides initial structural support and isolation, but it degrades in CO2-rich environments leading to loss of zonal isolation
Solution Approach 1:
The patent uses composite materials by combining Portland cement with pozzolanic materials (such as fly ash, silica fume, or metakaolin) to create a cement composition that resists CO2 degradation. The pozzolanic materials react with calcium hydroxide in the cement to form additional calcium silicate hydrate phases that are more resistant to carbonation, thereby improving long-term chemical stability and reliability of well isolation in CO2-rich environments.
Solution Approach 2:
The patent modifies the chemical composition parameters of the cement by adjusting the water-to-cement ratio, adding chemical admixtures, and controlling the proportions of different cementitious materials. These parameter changes optimize the cement's resistance to CO2 attack while maintaining adequate strength development and setting properties, resolving the contradiction between initial structural performance and long-term chemical stability.
2Ease of manufacture
If cement reacts with carbon dioxide, then carbonation products form, but compressive strength decreases and permeability increases
Solution Approach 1:
The patent converts the harmful effect of CO2 carbonation into a beneficial outcome by allowing controlled carbonation to occur, which transforms free calcium hydroxide into calcium carbonate precipitates. These precipitates fill pores and microcracks in the cement matrix, reducing permeability and actually improving long-term compressive strength despite the consumption of some calcium hydroxide. The harmful carbonation reaction is thus redirected to serve a strengthening function.
Solution Approach 2:
The patent utilizes the porous structure of cement as a beneficial feature by designing a controlled pore system that accommodates carbonation products. The porosity allows CO2 to diffuse in and react with cement phases, and the resulting calcium carbonate precipitates naturally fill and seal these pores over time, improving density and strength while maintaining the necessary permeability for initial hydration processes.
3Quantity of substance
If cement is exposed to supercritical CO2 conditions, then chemical degradation occurs, but long-term storage safety is compromised
Solution Approach 1:
The patent applies preliminary anti-action by pre-treating the cement with compounds that form protective layers on the cement surface before CO2 exposure. These pre-applied substances (such as silane coatings or reactive mineral additives) create a barrier that slows down or prevents CO2 from penetrating and attacking the cement matrix, thereby protecting the stored CO2 from leakage while maintaining storage capacity.
Solution Approach 2:
The patent introduces intermediary substances (such as corrosion inhibitors or protective coatings) that act as mediators between the cement and supercritical CO2. These intermediaries form stable compounds with CO2 or create physical barriers that prevent direct contact between CO2 and the cement matrix, reducing chemical degradation while allowing the cement to maintain its sealing function for long-term CO2 storage safety.
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 proposed cement composition demonstrates improved chemical stability and resistance to carbonation, maintaining mechanical properties and preventing CO2 migration, thus ensuring long-term well isolation and safe storage of carbon dioxide, as evidenced by enhanced durability tests in supercritical CO2 environments.
Implementation Method 1
The carbonation products meaning products from precipitation and/or calcium carbonate
Implementation Method 2
A cement composition incorporating hollow elements such as cenospheres or sodium-calcium-borosilicate glass microspheres, or a metakaolin-based or blast furnace slag-based cement slurry with optimized particle sizes and proportions to enhance chemical stability and durability in supercritical CO2 conditions
Implementation Method 3
a metakaolin-based or blast furnace slag-based cement slurry with optimized particle sizes and proportions
Data Source
AI summary
A cement composition resistant to carbon dioxide includes a hollow element for trapping carbonation products. The hollow element can be hollow spherical or quasi spherical particles including cenospheres, sodium-calcium-borosilicate glass microspheres, silica-alumina microspheres, or a combination thereof. Or the hollow element may be a spherical or quasi spherical void made in the set cement, for example by foaming the cement composition with a gas such as air, nitrogen or a combination thereof. The composition may be used to cement a subterranean well in which carbon dioxide is injected, stored or produced.