Supercritical CO2 Emulsion with Polyacrylate for Gravity Override
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Solution Overview
Problem
Supercritical CO2 used in enhanced oil recovery tends to bypass certain areas of hydrocarbon reservoirs due to its low density, leading to inefficient oil extraction and high water cut in produced hydrocarbons, a phenomenon known as 'gravity override'.
Innovation Solution
A CO2 emulsion is created with a continuous phase of supercritical CO2 and a discontinuous phase of anionic polyelectrolyte, such as polyacrylate, which absorbs aqueous fluid to increase the density of the CO2, preventing gravity override and enhancing sweep efficiency in hydrocarbon-bearing formations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If supercritical CO2 is used for enhanced oil recovery, then hydrocarbon displacement and viscosity reduction are improved, but density remains low causing gravity override and inefficient reservoir coverage
Solution Approach 1:
The patent creates a composite emulsion system combining supercritical CO2 with anionic polyelectrolyte (polyacrylate) droplets. The polyacrylate droplets absorb aqueous reservoir fluid to increase the overall density of the CO2 emulsion, while the supercritical CO2 maintains its hydrocarbon-displacing properties. This composite structure resolves the contradiction by integrating two materials with complementary properties.
Solution Approach 2:
The patent changes the density parameter of the CO2 system by introducing polyacrylate droplets that absorb water in situ. The density of the CO2 emulsion is dynamically adjusted as the polyacrylate absorbs aqueous reservoir fluid, transforming the low-density supercritical CO2 into a higher-density emulsion that resists gravity override while maintaining enhanced oil recovery effectiveness.
2Speed
If supercritical CO2 is injected into the reservoir, then hydrocarbon viscosity is reduced and flow is enhanced, but the CO2 bypasses certain areas due to low density and poor sweep efficiency
Solution Approach 1:
The patent introduces polyacrylate droplets as an intermediary substance within the CO2 system. These droplets act as density modifiers that absorb aqueous reservoir fluid to increase CO2 emulsion density, improving gravitational stability and sweep efficiency without interfering with the CO2's ability to dissolve in hydrocarbons and reduce their viscosity.
Solution Approach 2:
The patent modifies the density parameter of the CO2 system by incorporating polyacrylate droplets that absorb water. This parameter change enhances the gravitational stability of the CO2 emulsion, preventing it from bypassing reservoir areas, while the supercritical CO2 phase maintains its ability to enhance hydrocarbon flow through viscosity reduction.
3Ease of manufacture
If conventional CO2 flooding is used, then injection is simple and cost-effective, but water cut in produced hydrocarbons is high due to gravity override
Solution Approach 1:
The patent develops a composite CO2-polyacrylate emulsion that combines the simplicity of CO2 injection with the density-enhancing properties of polyacrylate. The emulsion can be injected through standard CO2 injection infrastructure, maintaining ease of implementation, while the polyacrylate droplets reduce gravity override and associated water production.
Solution Approach 2:
The patent uses polyacrylate droplets as an intermediary that can be co-injected with or dissolved in the CO2 stream using existing injection equipment. This intermediary substance modifies the CO2 density in situ by absorbing reservoir water, reducing water cut in produced hydrocarbons without requiring complex new injection systems.
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 dense CO2 emulsion effectively traverses deeper into the reservoir, reducing water cut and increasing hydrocarbon recovery by maintaining a higher density and stabilizing the emulsion for extended periods, thus overcoming the limitations of conventional CO2 flooding methods.
Implementation Method 1
absorbing an amount of the aqueous reservoir fluid into the polyacrylate of the emulsion to provide a dense CO2 emulsion
Implementation Method 2
CO2 may dissolve in the hydrocarbon fluid, reducing the viscosity of the hydrocarbon fluid and causing it to swell
Data Source
AI summary
A composition includes a carbon dioxide (CO2) emulsion including a continuous critical or supercritical CO2 phase and a discontinuous phase including a polyacrylate. A method of making a CO2 emulsion includes providing a first solution of a polyacrylic acid and critical or supercritical CO2, providing a second solution of a base and critical or supercritical CO2, and mixing the first solution and the second solution such that the polyacrylic acid and the base react to form an emulsion of polyacrylate droplets in critical or supercritical CO2. A method of treating a hydrocarbon-bearing formation includes introducing an emulsion including a continuous CO2 phase and a discontinuous phase comprising a polyacrylate into the formation, contacting the emulsion with an aqueous reservoir fluid in the hydrocarbon-bearing formation, and absorbing an amount of the aqueous reservoir fluid into the polyacrylate of the emulsion to provide a dense CO2 emulsion.