Latent Curing Agent for Low pH Frac Fluid Sand Consolidation
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Solution Overview
Problem
Conventional sand consolidation treatments in subterranean operations using plastic resins are unsatisfactory due to reduced permeability, high costs, operational difficulties, and the risk of rapid exothermic reactions with acids, which complicates the curing process and affects the stability of fracturing fluids.
Innovation Solution
A method involving a hardenable acid curable resin and a hydrolysable strong acid ester, where the ester yields an acid with a pKa at or below 3, allowing for a single-component system that can be stored and activated in situ, enabling effective consolidation of sand and proppant particles at low temperatures, reducing the risk of exothermic reactions, and maintaining permeability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional plastic resins are used for sand consolidation, then the sand particles can be cemented together, but the permeability of the consolidated formation is reduced below acceptable levels
Solution Approach 1:
The patent changes the chemical parameters of the curing system by using a latent curing agent that remains inactive at low pH and only activates when exposed to alkali. This parameter change allows the resin to cure slowly and controlled manner, forming a more open cellular structure that maintains permeability while achieving adequate consolidation strength.
2Temperature
If furan-based resins are used for sand consolidation, then the resin can be cured at high temperature, but rapid exothermic reactions occur when mixed with acids, causing degradation of fluid viscosity
Solution Approach 1:
The patent introduces a latent curing agent as an intermediary substance that does not react with acids under normal conditions. The curing agent remains dormant until exposed to alkali, at which point it activates slowly without causing rapid exothermic reactions. This intermediary approach eliminates the harmful interaction between acids and furan-based resins while maintaining curing capability.
Solution Approach 2:
The patent performs preliminary action by pre-mixing the resin with a latent curing agent that is inactive at the time of application. The curing reaction is postponed until the resin is exposed to alkali conditions in the formation, allowing controlled curing without premature exothermic reactions with acidic fracturing fluids.
3Ease of manufacture
If conventional curing agents are added to resins, then the resin can be cured, but rapid and exothermic reactions occur, complicating the curing process
Solution Approach 1:
The patent applies dynamics by making the curing process conditional and controllable. The latent curing agent remains inactive under acidic conditions and only becomes active when exposed to alkali, allowing the curing process to be dynamically controlled based on the chemical environment. This provides ease of manufacture with reliable reaction control.
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 controlled consolidation of sand and proppant particles, maintaining permeability and reducing operational challenges, while being cost-effective and capable of handling a wide range of temperatures, ensuring efficient fluid production and well integrity.
Implementation Method 1
a hydrolysable strong acid ester, wherein said ester upon hydrolyzing yields an acid with a pKa at or below about 3
Implementation Method 2
forming consolidated particulates upon the contacting of the unconsolidated particles with the reaction product of the hardenable acid curable resin and hydrolysable strong acid ester upon hydrolyzing in the formation
Data Source
AI summary
A method of treating a subterranean formation including providing a treatment fluid comprising a hardenable acid curable resin and a hydrolysable strong acid ester. The treatment fluid is combined with a diluent fluid and is introduced into a subterranean formation. Upon the hydrolyzing of the ester in the formation and the contacting of unconsolidated proppants, the treatment method produces consolidated proppants.