Reversible Aminal Gel for Wellbore Conformance and Flow Restoration
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Solution Overview
Problem
Conventional crosslinked water conformance gels lack reversibility between a flowable fluid state and a substantially solid gel state, making it difficult to remove gel treatments that miss targeted water-producing zones, leading to hydrocarbon flow disruptions.
Innovation Solution
Development of reversible aminal gels produced from the condensation of aldehydes and amines, which exhibit dynamic responsivity to divalent and trivalent metal salts, allowing for phase change dynamics and mechanical property modification, enabling transformation between liquid and gel states in response to pH changes or metal salt additions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional crosslinked water conformance gels are used, then fluid loss control and well pressure control are achieved, but the gels cannot be removed and cause hydrocarbon flow disruptions
Solution Approach 1:
The patent applies dynamics by creating gels that can dynamically transition between solid and liquid states in response to pH changes. The gel system uses reversible chemical bonding that allows it to adapt its physical state based on environmental conditions, enabling it to function as a solid gel for fluid loss control and then transform into a liquid for removal.
Solution Approach 2:
The patent utilizes parameter changes by leveraging pH as a control parameter to trigger gelation and degelation. By changing the pH parameter of the formation fluid, the gel can be activated for fluid loss control and subsequently deactivated for removal, solving the contradiction between maintaining control and enabling removal.
2Reliability
If conventional gels are used for sand control, then sand migration is prevented, but the gels cannot be reversed and disrupt hydrocarbon flow
Solution Approach 1:
The gel system is designed to be dynamic, transitioning from a solid state for sand control to a liquid state for restoring hydrocarbon flow. This dynamic behavior allows the gel to perform its sand control function temporarily and then reverse, preventing permanent disruption to productivity.
Solution Approach 2:
The system maintains continuity of useful action by ensuring that after sand control is achieved, the gel can be reversed to restore flow without leaving harmful residues. The reversible nature ensures that the formation permeability is restored, maintaining continuous productive operation.
3Reliability
If conventional gels are used for conformance, then water conformance is achieved, but the gels cannot be removed and require well intervention
Solution Approach 1:
The gel system provides self-service by automatically reversing and removing itself through pH-induced degelation. This eliminates the need for complex well intervention procedures to remove the gel, as the system handles its own removal through chemical transformation in response to formation conditions.
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 reversible aminal gels provide high thermal stability up to 200°C, allowing for controlled gelation and degelation, reducing formation damage and enabling effective wellbore operations, including sand control, conformance, and cement applications with tunable gel-time and self-healing properties.
Implementation Method 1
Hemiaminal and aminal polymers have been reported to undergo pH responsive phase change and network rearrangements
Implementation Method 2
In addition to pH responsiveness, hemiaminal gels also show dynamics through aminal/thiol-exchange
Implementation Method 3
An assortment of different reversible reactions has been investigated in this class of materials. These include reversible hydrazone formation, reversible Schiff base formation, reversible aminal formation, Diels-Alder condensations, disulfide exchange, dithioacetal exchange, dynamic boronic ester formation, olefin metathesis, and metal-ligand association
Data Source
AI summary
A well treatment composition for use in a hydrocarbon-bearing reservoir comprising a reversible aminal gel composition. The reversible aminal gel composition includes a liquid precursor composition. The liquid precursor composition is operable to remain in a liquid state at about room temperature. The liquid precursor composition comprises an organic amine composition; an aldehyde composition; and a polar aprotic organic solvent. The liquid precursor composition transitions from the liquid state to a gel state responsive to an increase in temperature in the hydrocarbon-bearing reservoir. The gel state is stable in the hydrocarbon-bearing reservoir at a temperature similar to a temperature of the hydrocarbon-bearing reservoir, and the gel state is operable to return to the liquid state responsive to a change in the hydrocarbon-bearing reservoir selected from the group consisting of: a decrease in pH in the hydrocarbon-bearing reservoir and an addition of excess metal salt composition in the hydrocarbon-bearing reservoir.