High-Temperature Hydrogel Composition for Reservoir Conformance Control
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Solution Overview
Problem
Conventional hydrogels used for enhanced oil recovery are hydrolytically unstable at high temperatures and salinity, limiting their use in high-temperature oil reservoirs, and existing preformed particle gels face issues like degradation and lack of control over gelation time.
Innovation Solution
Development of non-toxic, thermally stable hydrogel compositions comprising swellable particles with crosslinkers interspersed among crosslinkable polymer chains, capable of forming covalent bonds, which maintain less than 50% volume decrease at temperatures up to 150°C for extended periods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional hydrogels based on polyacrylamides and polyacrylates are used for enhanced oil recovery, then they provide effective fluid flow control at lower temperatures, but they undergo rapid molecular structure degradation and hydrolysis at temperatures above 105°C, limiting their use in high-temperature reservoirs
Solution Approach 1:
The patent changes the chemical parameters of the hydrogel system by replacing conventional polyacrylamide/polyacrylate polymers with thermally stable polymers containing sulfonate groups (such as poly(2-acrylamido-2-methylpropanesulfonic acid) or poly(sodium 4-styrenesulfonate)). This parameter change in polymer chemistry enables the hydrogel to maintain structural integrity at temperatures up to 150°C while preventing hydrolytic degradation that plagues conventional systems.
2Ease of manufacture
If in-situ crosslinking gels are used to plug thief zones, then they can be formed within the reservoir, but they lack control over gelation time and exhibit gelling uncertainty due to shear degradation, chromatographic fractionation, and dilution
Solution Approach 1:
The patent applies preliminary action by pre-synthesizing and pre-crosslinking the polymer gel into stable particle form above ground before injection. The particles contain dormant crosslinking sites that become activated only upon contact with formation water at reservoir conditions, ensuring controlled gelation timing and eliminating the uncertainties associated with in-situ crosslinking while maintaining the ability to plug thief zones effectively.
3Ease of operation
If preformed particle gels are used to overcome in-situ gel treatment drawbacks, then they provide controlled swelling and plugging capability, but they degrade at high temperatures and lack long-term thermal stability in reservoirs above 105°C
Solution Approach 1:
The patent creates composite hydrogel particles by combining thermally stable polymers containing sulfonate functional groups with appropriate crosslinking agents. This composite material structure provides both the controlled swelling characteristics of preformed particles and the thermal durability required for long-term operation at temperatures up to 150°C, eliminating the degradation issues of conventional preformed gels.
4Productivity
If hydrogels are used to plug water thief zones and improve oil recovery, then they can control fluid flow conformance, but they must meet stringent environmental regulations regarding aquatic toxicity in high-temperature reservoirs
Solution Approach 1:
The patent changes the chemical composition parameters by selecting polymers and crosslinking agents that are inherently non-toxic to aquatic environments. The use of sulfonate-containing polymers and environmentally benign crosslinking systems ensures that the hydrogel maintains its oil recovery enhancement capabilities while meeting stringent environmental regulations for high-temperature reservoirs.
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 hydrogels exhibit superior thermal stability and mechanical integrity, effectively controlling fluid flow and improving hydrocarbon recovery in high-temperature and high-salinity environments, while being non-toxic to aquatic environments.
Implementation Method 1
The one or more crosslinkers are capable of forming covalent bonds between the polymer chains
Implementation Method 2
on contact with water, have ability to swell up to a hundred times of the original size
Data Source
AI summary
Compositions of swellable non-toxic hydrogels and their use in conformance control are described herein. More specifically, the present invention generally relates to the hydrogels compositions that can be used to treat the oil reservoirs having high temperature and high salinity conditions. The compositions generally comprise a plurality of swellable particles having one or more crosslinkers interspersed within a polymer matrix. The compositions can also be used in biomedical, agricultural, fracking and similar applications wherein thermally-stable, nontoxic hydrogels are required.