Hydrazide Curing Agents for Delayed Epoxy Resin Setting
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Solution Overview
Problem
Existing cement compositions used in subterranean formations often cure prematurely due to the reactivity of traditional amine curing agents with epoxy resins at room temperature, limiting the time available to place the cement before it sets in drilling equipment or before reaching the desired location in the wellbore.
Innovation Solution
The use of hydrazide curing agents, which are partially or substantially insoluble in epoxy resins at room temperature and unreactive until reaching their activation temperature, allowing for delayed curing and extended pumpability of the curable resin compositions, enabling longer placement times and storage at ambient temperatures without curing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If traditional amine curing agents are used with epoxy resins, then the cement composition cures quickly and achieves early strength, but the composition cures prematurely during handling and transportation, limiting placement time
Solution Approach 1:
The patent changes the chemical parameters of the curing agent by using hydrazide derivatives instead of traditional amine curing agents. This substitution fundamentally alters the reactivity profile, allowing the system to maintain low reactivity during handling while achieving rapid cure upon placement, thus resolving the contradiction between early strength development and extended placement time.
Solution Approach 2:
The patent introduces dynamic control over the curing process through temperature-activated reactivity. The hydrazide-based curing agent remains relatively unreactive at ambient temperatures during handling but becomes highly reactive when exposed to formation temperatures or heat from cement hydration, enabling the system to adapt its curing rate to the operational stage.
2Duration of action of stationary object
If traditional amine curing agents are used, then rapid curing occurs, but the composition cannot be stored or transported for extended periods without curing
Solution Approach 1:
The patent applies parameter changes by selecting curing agents (hydrazide derivatives) with fundamentally different reactivity characteristics compared to traditional amines. This enables the composition to maintain stability during storage and transport while achieving rapid curing when needed, effectively decoupling storage duration from curing speed.
Solution Approach 2:
The patent prepares the cement composition in advance with the hydrazide-based curing agent already incorporated, allowing it to be stored and transported in a ready-to-use state without premature curing. The composition is pre-configured to activate its curing function only when exposed to formation conditions, eliminating the need for on-site mixing and extending the operational window.
3Ease of operation
If on-site mixing is required to prevent premature curing, then placement flexibility is reduced, but if pre-mixed compositions are used, then handling time is extended
Solution Approach 1:
The patent performs preliminary action by pre-mixing the cement composition with the hydrazide-based curing agent during manufacturing, creating a stable, ready-to-place composition. This eliminates the need for on-site mixing operations while maintaining extended handling time, as the pre-mixed composition remains stable during transport and can be placed whenever needed within the extended operational window.
Solution Approach 2:
The patent uses parameter changes in the curing agent chemistry to enable pre-mixing without premature curing. The hydrazide-based system's reduced reactivity at ambient temperatures allows the composition to be prepared in advance and stored or transported in mixed form, providing both placement flexibility and extended handling time simultaneously.
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 approach allows for greater flexibility in placing the curable resin compositions in subterranean formations by delaying the curing process, enabling longer handling times and eliminating the need for on-site mixing, thus improving the efficiency of cementing operations and remedial operations.
Implementation Method 1
the curing agent is partially or substantially insoluble in the epoxy resin such that the curable resin composition does not begin to cure
Implementation Method 2
the curable resin composition may be stored at temperatures below the activation temperature without curing
Implementation Method 3
combining an epoxy resin and a curing agent to form a curable resin composition... allowing the curable resin composition to at least partially cure
Data Source
AI summary
Curable resin compositions comprising an epoxy resin and a hydrazide curing agent and methods for using the curable resin compositions in cementing and/or remedial operations in a subterranean formation are provided. In one embodiment, the method may comprise combining an epoxy resin and a curing agent to form a curable resin composition, wherein the curing agent comprises a hydrazide curing agent; introducing the curable resin composition into a subterranean formation; and allowing the curable resin composition to at least partially cure.