Sequential Solvent Hot Water Polymer Injection for Heavy Oil Recovery
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Solution Overview
Problem
Current methods for heavy oil recovery, such as waterflooding, thermal methods, and vapor extraction, face challenges due to the high viscosity and density of heavy oil, leading to low recovery rates and high costs, with polymer flooding requiring high concentrations and increased expenses.
Innovation Solution
A sequential method involving the introduction of a solvent, followed by hot water, and then a polymer solution into a heavy oil reservoir through an injection well, to reduce viscosity and enhance mobility, with the solvent and hot water mixture interacting with the heavy oil to form a mixture that is retrieved from a production well.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If waterflooding is used for heavy oil recovery, then the process is simple and low cost, but the recovery rate is low due to high viscosity and density of heavy oil
Solution Approach 1:
The patent combines solvent flooding and hot water flooding into a composite recovery method. The solvent (naphtha or kerosene) mixes with hot water to create a synergistic effect where the solvent reduces oil viscosity through dissolution while hot water provides thermal energy, together achieving much better recovery results than either method alone.
Solution Approach 2:
The patent changes the physical and chemical parameters of the injection fluid by combining solvent and hot water. The solvent concentration (10-50% by volume) and temperature (80-150°C) are optimized to dramatically reduce heavy oil viscosity and improve mobility, enabling effective recovery that simple waterflooding cannot achieve.
2Productivity
If thermal methods are used for heavy oil recovery, then the viscosity of heavy oil is reduced, but the energy consumption is high
Solution Approach 1:
The patent introduces solvent (naphtha or kerosene) as an intermediary substance that mediates between the hot water and heavy oil. The solvent acts as a chemical catalyst that dramatically reduces oil viscosity through dissolution, reducing the amount of thermal energy needed compared to pure thermal methods.
Solution Approach 2:
The patent optimizes the temperature parameter (80-150°C) to be lower than conventional steam flooding, while the solvent concentration (10-50% by volume) is optimized to achieve sufficient viscosity reduction. This parameter optimization reduces energy consumption while maintaining effective mobility improvement.
3Productivity
If polymer flooding is used for heavy oil recovery, then the mobility ratio is improved, but the polymer concentration must be high leading to increased costs
Solution Approach 1:
The patent performs preliminary solvent flooding and hot water flooding before polymer injection. This preliminary action pre-reduces the heavy oil viscosity and improves base mobility, so that when polymer is injected later, much lower concentrations are needed to achieve the desired mobility ratio improvement.
Solution Approach 2:
The patent changes the mobility ratio through sequential parameter adjustments: first using solvent concentration (10-50%) and temperature (80-150°C) to reduce viscosity, then using lower polymer concentrations (0.1-1.0%) to fine-tune the mobility ratio, achieving effective mobility control without high polymer doses.
4Productivity
If vapor extraction is used for heavy oil recovery, then the heavy oil is extracted, but the process is slow and costly
Solution Approach 1:
The patent utilizes phase transitions of the solvent (liquid injection → vapor phase in reservoir → liquid phase upon condensation). The injected solvent vaporizes in the hot reservoir, extracts heavy oil components, then condenses in the production well, creating a rapid cyclic extraction process that is much faster than conventional vapor extraction.
Solution Approach 2:
The patent optimizes temperature (80-150°C) and solvent concentration (10-50% by volume) parameters to achieve rapid phase transitions and fast extraction kinetics. The hot water provides thermal energy for rapid vaporization, while the solvent concentration is optimized for maximum extraction efficiency, dramatically reducing extraction time compared to conventional methods.
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 method effectively reduces the viscosity of heavy oil, increasing its mobility and recovery rates while minimizing the use of solvent and energy, and using lower polymer concentrations to achieve efficient and cost-effective heavy oil extraction.
Implementation Method 1
The sequentially introduced solvent, hot water, and polymer solution fluids intermingle with the heavy oil within the reservoir to form a heavy oil mixture
Implementation Method 2
a solvent and hot water are sequentially introduced via an injection well traversing a subsurface into a reservoir containing a heavy oil
Implementation Method 3
introducing a polymer solution into the reservoir via the injection well. The sequentially introduced solvent, hot water, and polymer solution fluids intermingle with the heavy oil within the reservoir to form a heavy oil mixture that is retrieved from a production well
Data Source
AI summary
A method for retrieving heavy oil from a reservoir by injection of solvent, hot water, and polymer solution. This method includes the steps of providing an injection well traversing into reservoir containing heavy oil. Sequential injections of solvent, a hot water and polymer solution are performed via the injection well traversing into reservoir containing the heavy oil. The solvent, hot water, and polymer solution intermingle with the heavy oil within the reservoir to form a heavy oil mixture that is retrieved from a production well. The sequential solvent and hot water injection may also be repeated to reduce the viscosity of the heavy oil until an estimated viscosity of the heavy oil in the reservoir is below a threshold viscosity before injecting polymer solution into the reservoir.