In Situ Refractory Binder Compositions for Subterranean Corrosion
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Solution Overview
Problem
Cement compositions used in subterranean operations face challenges with corrosion and heat resistance, particularly in high-temperature environments where they can deteriorate due to reactions with carbonic acid, leading to increased permeability and potential well casing failure.
Innovation Solution
A binder composition comprising a calcium ion source, high-alumina refractory aluminosilicate pozzolan, and water, which reacts in situ to form cementitious materials, providing improved corrosion and heat resistance without the need for clinker or cementitious constituents, and can include additives like accelerants and microspheres for enhanced properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional Portland cement is used in high-temperature subterranean environments, then initial setting and basic bonding are achieved, but the cement deteriorates due to carbonic acid corrosion, increasing permeability and causing casing failure
Solution Approach 1:
The patent converts the harmful effect of carbonic acid by using a binder composition that is inherently resistant to carbonic acid corrosion. Instead of trying to protect the cement from the acid, the solution uses materials (high-alumina refractory cement, pozzolans, silica fume) that are chemically resistant to the corrosive environment, thereby converting the corrosive condition into a non-threatening environment for the cement sheath.
Solution Approach 2:
The patent employs a composite binder composition consisting of multiple components: high-alumina refractory cement, pozzolans (such as fly ash or silica fume), and water. This composite material combines the heat resistance of high-alumina cement with the corrosion resistance and strength development of pozzolanic reactions, creating a material that withstands both high temperature and carbonic acid corrosion simultaneously.
2Reliability
If high-alumina refractory cement and pozzolans are used to improve corrosion and heat resistance, then chemical stability in corrosive environments is achieved, but the setting time and early strength development may be affected
Solution Approach 1:
The patent ensures continuous strength development through the pozzolanic reaction, which continues to occur over an extended period. The initial set is provided by the high-alumina refractory cement, while the pozzolans continue to react with calcium hydroxide to form additional calcium silicate hydrate and calcium aluminate hydrate, providing continuous strength gain and eventual surpassing of conventional cement strength without compromising the continuous protective function against corrosion.
3Ease of manufacture
If conventional cement compositions are used, then ease of manufacture and availability of materials are maintained, but the cement fails in high-temperature geothermal wells, leading to lost production and expensive repairs
Solution Approach 1:
The patent changes the chemical composition parameters of the cement by using high-alumina refractory cement instead of conventional Portland cement and incorporating pozzolans. These parameter changes in the material composition enable the cement to withstand high temperatures and corrosive environments while still using materials that can be manufactured and obtained through established industrial processes, maintaining ease of manufacture.
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 binder composition effectively forms a durable, heat-resistant cement sheath that maintains integrity in high-temperature and corrosive conditions, reducing the risk of well casing failure and extending the lifespan of subterranean formations.
Implementation Method 1
A binder composition may comprise a calcium ion source, high-alumina refractory aluminosilicate pozzolan, and water
Implementation Method 2
carbonic acid (H2CO3) may be produced by reaction of subterranean water and carbon dioxide (CO2), which may react with calcium hydroxide that may be present in some cements, which reaction may corrode the cement
Implementation Method 3
high-alumina refractory aluminosilicate pozzolan...demonstrating improved corrosion and heat resistance
Data Source
AI summary
Corrosion-resistant refractory binder compositions may be formed with a calcium ion source, high-alumina refractory aluminosilicate pozzolan, and water. Any one or more of such components may individually be non-cementitious. Examples of high-alumina refractory aluminosilicate pozzolan include crushed firebrick; firebrick grog; and mixtures of silicate and any one or more of corundum, high-alumina ceramic, and bauxite; refractory mortar; fire clay; mullite; fused mullite; and combinations thereof, among others. A binder composition may be mixed with sufficient amount of water to form a slurry, which slurry may be introduced into a subterranean formation (e.g., via a wellbore penetrating the subterranean formation). A plurality of the non-cementitious components may react in the presence of water when exposed to suitable conditions so as to enable the binder composition to set. Such compositions, once set, may exhibit enhanced corrosion and/or heat resistance as compared to other binder compositions.