Dense Phase CO2 Co-Injection for Reservoir Storage
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Solution Overview
Problem
The challenge lies in efficiently storing large quantities of carbon dioxide (CO2) in porous and permeable hydrocarbon reservoirs for long-term sequestration while minimizing its miscibility with hydrocarbons, as existing methods for enhanced oil recovery and CO2 storage have conflicting requirements, and the large volumes of CO2 injected can lead to increased production of CO2 vapor, overwhelming existing injection facilities and reducing storage efficiency.
Innovation Solution
Converting the produced vapor stream into a dense phase state and mixing it with an imported CO2 stream, either in a liquid or supercritical state, to form a co-injection stream that is injected into the hydrocarbon reservoir, thereby maximizing storage capacity and reducing the need for additional injection infrastructure and costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If CO2 is injected into a hydrocarbon reservoir for enhanced oil recovery, then hydrocarbon production is improved, but CO2 storage efficiency deteriorates because CO2 becomes miscible with hydrocarbons and is produced back with the hydrocarbons
Solution Approach 1:
The invention changes the physical parameters of CO2 by compressing it to dense phase conditions (high pressure and temperature within the dense phase region of the phase diagram). This parameter change transforms CO2 from a gaseous or supercritical state that mixes with hydrocarbons into a dense phase state that remains as a separate phase, preventing miscibility and enabling simultaneous EOR and storage
Solution Approach 2:
The invention utilizes phase transition by maintaining CO2 in the dense phase region of its phase diagram during injection and reservoir contact. This phase state is distinct from both gaseous and supercritical states, creating a dense liquid-like phase that does not mix with hydrocarbons, thereby allowing CO2 to remain in the reservoir for storage while still providing EOR benefits
2Quantity of substance
If large quantities of CO2 are injected for sequestration, then CO2 storage capacity is improved, but injection facility reliability deteriorates due to overwhelming volumes and increased CO2 vapor production
Solution Approach 1:
By changing CO2 to dense phase conditions, the invention increases CO2 density by a factor of 5-10 times compared to gaseous state. This parameter change allows much larger quantities of CO2 to be injected through the same facility infrastructure, preventing overwhelming of injection facilities while maintaining high storage capacity
Solution Approach 2:
The invention enables continuous injection of large CO2 volumes by maintaining CO2 in a dense phase that can be continuously pumped and injected without the intermittent issues caused by vapor production and phase separation. The dense phase state allows for steady, reliable injection operations
3Quantity of substance
If CO2 is injected at a distance from production wells to maximize storage, then CO2 storage efficiency is improved, but infrastructure requirements worsen due to limited well placement options
Solution Approach 1:
The invention makes existing injection wells multi-functional by enabling them to inject dense phase CO2 that serves both EOR and storage purposes. This universality allows the same infrastructure to achieve dual objectives without requiring separate dedicated storage injection wells, reducing infrastructure complexity
4Ease of operation
If CO2 is maintained in a low density state for easy injection, then injection ease is improved, but storage capacity deteriorates because less CO2 can be stored per unit volume
Solution Approach 1:
The invention optimizes the balance between injection ease and storage capacity by selecting dense phase conditions that provide sufficient density multiplication (5-10x) while maintaining fluid properties that allow for practical injection. The dense phase state offers a compromise between gaseous state ease of injection and liquid state storage density
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 enhances CO2 storage by increasing the density of the injected CO2, allowing for reliable and efficient injection, reducing the risk of CO2 leakage, and improving hydrocarbon recovery through improved sweep efficiency and reduced pressure buildup in the reservoir, while minimizing the need for additional injection capacity and infrastructure.
Implementation Method 1
compressing the produced vapour stream to above the cricondenbar for the composition of the produced vapour stream
Implementation Method 2
cooling the compressed stream thereby forming a cooled stream that is in a dense phase state
Implementation Method 3
mixing the cooled stream from step (d) with the imported CO2 stream thereby forming a co-injection stream
Implementation Method 4
injecting the co-injection stream into the hydrocarbon bearing reservoir from said injection well
Data Source
Figure 1~2
AI summary
A method of storing CO2 in a porous and permeable hydrocarbon reservoir having at least one injection well and at least one production well penetrating said reservoir, which method comprises the steps of: (a) recovering a produced fluid stream comprising produced hydrocarbons, produced water, and produced CO2 from the production well; (b) passing the produced fluid stream to a production facility where a produced vapour stream comprising carbon dioxide and volatile hydrocarbons is separated from the produced fluid stream; (c) compressing the produced vapour stream to above the cricondenbar for the composition of the produced vapour stream; (d) cooling the compressed stream thereby forming a cooled stream that is in a dense phase state; (e) importing a CO2 stream to an injection facility wherein the imported CO2 is either in a liquid state or a supercritical state; (f) mixing the cooled stream from step (d) with the imported CO2 stream thereby forming a co-injection stream; and (g) injecting the co-injection stream into the hydrocarbon bearing reservoir from said injection well.