Nonionic Surfactant Dispersion for CO2 Mobility Control
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Solution Overview
Problem
Current gas flooding methods for enhanced petroleum recovery face issues such as poor sweep of subterranean formations due to unstable dispersions and surfactant loss, leading to reduced petroleum recovery and increased costs.
Innovation Solution
The use of a nonionic surfactant in dispersion compositions with carbon dioxide and water to form stable dispersions that improve the mobility ratio and reduce viscosity, preventing gas from bypassing significant portions of the formation and promoting more efficient petroleum recovery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If traditional surfactants (e.g., ethoxy-sulfates) are used in gas flooding processes, then the gas can reduce the viscosity of petroleum, but the dispersions formed are unstable and break/dissolve in the subterranean formation, leading to poor sweep and early breakthrough
Solution Approach 1:
The patent changes the chemical parameters of the surfactant by selecting nonionic surfactants with specific molecular structures (containing hydrophobic groups like alkyl or aryl groups and hydrophilic groups like polyethylene oxide chains) that maintain stability in high salinity and temperature conditions. This parameter change resolves the contradiction by enabling stable dispersions that maintain productivity.
Solution Approach 2:
The patent uses composite surfactant systems combining nonionic surfactants with specific molecular architectures that integrate both hydrophobic and hydrophilic components in optimized ratios. This composite approach creates dispersions that are both stable and effective at improving mobility ratio, resolving the contradiction between stability and productivity.
2Speed
If gas flooding is performed to reduce petroleum viscosity, then the viscosity of petroleum decreases and flow increases, but the gas bypasses significant portions of the formation due to poor sweep, leaving petroleum unrecovered
Solution Approach 1:
The patent introduces a dispersion of gas bubbles in water as an intermediary medium. This dispersion acts as a mediator that improves the mobility ratio by increasing the apparent viscosity of the injected fluid, thereby improving sweep efficiency and ensuring that the gas contacts more petroleum while still maintaining adequate flow rates.
Solution Approach 2:
The patent changes the physical parameters of the injected fluid by creating a dispersion that increases the apparent viscosity. This parameter change allows the injected fluid to move more uniformly through the formation, improving sweep efficiency and increasing the quantity of petroleum recovered while maintaining acceptable flow speeds.
3Ease of operation
If the mobility ratio between petroleum and injected gas is high, then the less viscous gas fingers through the viscous petroleum, but this further limits recovery of the petroleum
Solution Approach 1:
The patent uses a water-based dispersion containing gas bubbles as an intermediary that modifies the mobility characteristics of the injected fluid. This intermediary increases the apparent viscosity of the injected phase, balancing the mobility ratio and preventing fingering while maintaining the simplicity of the gas injection process.
4Stability of the object's composition
If surfactants with high affinity to formation rock are used, then they can stabilize dispersions, but they adsorb into the formation rock leading to surfactant loss and reduced effectiveness
Solution Approach 1:
The patent changes the chemical parameters of the surfactant by selecting nonionic surfactants with specific molecular structures that have reduced affinity for rock surfaces compared to traditional anionic surfactants. This parameter change allows the surfactant to maintain dispersion stability while minimizing adsorption losses to the formation rock.
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 nonionic surfactant-based dispersion compositions enhance petroleum recovery by maintaining stability at high salinity and temperature, increasing the apparent viscosity of carbon dioxide, and directing it towards unswept portions of the formation, thereby improving sweep efficiency and reducing costs.
Implementation Method 1
the nonionic surfactant promotes the formation of a dispersion from carbon dioxide and water
Implementation Method 2
A dispersion can generate an apparent viscosity of about 100 to about 1,000 times that of the injected gas improving the mobility ratio
Implementation Method 3
Carbon dioxide, which acts as a solvent to reduce the viscosity of the petroleum present in the subterranean formation
Implementation Method 4
the nonionic surfactant-based dispersion compositions enhance petroleum recovery by maintaining stability at high salinity and temperature
Data Source
AI summary
Embodiments of the present disclosure include dispersion compositions having a nonionic surfactant for use in enhanced petroleum recovery, and methods of using the dispersion compositions in petroleum recovery processes. For the various embodiments, the nonionic surfactant of the dispersion composition promotes the formation of a dispersion from carbon dioxide and water.