Hydrazide Crosslinked Polymer Emulsions for Oil Recovery
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Solution Overview
Problem
Current enhanced oil recovery techniques face challenges with poor sweep efficiency due to differences in water and oil mobility, and permeability variations in oil reservoirs, leading to incomplete oil recovery.
Innovation Solution
The use of an aqueous flooding fluid containing a crosslinked water-soluble polymer with multifunctional hydrazide-derived crosslinks, which degrades upon contact with the hydrocarbon formation to increase viscosity, improving the mobility control and sweep efficiency of the flooding fluid.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If high molecular weight water-soluble polymers are used to improve sweep efficiency, then viscosity increases and mobility control improves, but the polymers undergo molecular weight breakdown and degradation due to temperature, high shear, oxidative stress, and physical force
Solution Approach 1:
The patent applies preliminary action by pre-crosslinking the polymer chains before injection to form a stable three-dimensional network structure. This crosslinked structure is prepared in advance to resist degradation during injection and transport, maintaining polymer integrity until the flooding fluid reaches the reservoir where it is needed for mobility control.
Solution Approach 2:
The patent employs composite materials by creating a crosslinked polymer network that combines multiple functional groups (carboxyl, hydroxyl, amide) within a single polymer structure. This composite structure provides both the viscosity enhancement needed for sweep efficiency and the structural stability to resist thermal, shear, and oxidative degradation.
2Productivity
If crosslinked polymers are used to maintain viscosity and improve mobility control, then sweep efficiency improves, but the crosslinks may prevent complete degradation and reduce polymer flexibility
Solution Approach 1:
The patent applies local quality by introducing crosslinks at specific locations within the polymer chain at controlled densities. The crosslinking is not uniform throughout the entire polymer structure but is strategically placed to provide stability where needed while maintaining flexibility and degradability in other regions. This localized crosslinking optimizes both mobility control and structural responsiveness.
3Adaptability or versatility
If polymers are designed to degrade after contact with formation to improve mobility control, then the fluid can adapt to reservoir conditions, but the degradation timing and extent must be precisely controlled
Solution Approach 1:
The patent applies parameter changes by designing the polymer with specific functional groups (carboxyl, hydroxyl, amide) and crosslink density that respond to reservoir conditions such as temperature, pH, and ionic strength. These parameter changes trigger controlled degradation at the appropriate time and location, allowing the fluid to adapt from a stable injected state to a degraded reservoir state for optimal mobility 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 enhances oil recovery by maintaining high viscosity and mobility control within the reservoir, effectively displacing oil and improving secondary/tertiary recovery rates.
Implementation Method 1
the crosslinks within the crosslinked water-soluble polymer are derived from reaction of the multifunctional hydrazide with the carbonyl group of the water-soluble polymer
Implementation Method 2
the crosslinks are degraded after the aqueous flooding fluid comprising the cross-linked water-soluble polymer is contacted with the hydrocarbon containing formation
Data Source
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AI summary
Emulsions of mobility control polymers can be used to increase recovery of crude oil from a subterranean hydrocarbon-containing formation. A flooding fluid comprising the polymer emulsions are injected into a well that is in contact with the subterranean hydrocarbon-containing formation. The polymers can be temporarily cross-linked via hydrolyzable crosslinking moieties derived from a multifunctional hydrazide, a multifunctional amine, a multifunctional hydroxylamine, or a combination thereof and have improved injectivity into the well; the improved injectivity can be measured in terms of the flooding fluid's filter ratio, flow rate, and viscosity.