Fluid Injection Control Valve for CO2 Phase Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Injecting CO2 into depleted hydrocarbon reservoirs is challenging due to phase change behavior under low pressure conditions, leading to instability and potential deposition of solid CO2, as the pressure in these reservoirs is often below the critical pressure of CO2, causing phase changes and flow issues.
Innovation Solution
A method involving an injection facility that maintains CO2 in a liquid or supercritical state by using a fluid injection control valve within the injection tubing, which opens when the pressure exceeds a pre-set value, ensuring the CO2 remains in a stable state and preventing phase transitions, and is designed to operate at pressures above the critical pressure of CO2.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If CO2 is injected into a depleted reservoir with pressure below critical pressure, then CO2 storage is achieved, but phase change to gas occurs causing injection instability and potential solid CO2 deposition
Solution Approach 1:
The injection tubing is pre-filled with liquid CO2 before injection begins. This preliminary action ensures that the CO2 remains in liquid phase during injection, preventing phase change to gas and maintaining injection stability. The pre-filled liquid CO2 acts as a buffer that prevents pressure drops below the CO2 phase diagram curve.
Solution Approach 2:
Liquid CO2 is injected beforehand to create a cushion or buffer zone in the injection tubing. This cushion prevents subsequent CO2 injections from experiencing pressure drops that would cause phase change to gas. The liquid CO2 cushion absorbs pressure fluctuations and maintains stable injection conditions.
2Reliability
If CO2 is injected at high pressure to maintain liquid phase, then injection stability is improved, but additional compression equipment and energy are required
Solution Approach 1:
The system uses the CO2 itself to maintain injection stability. Liquid CO2 is injected to create a self-sustaining system where the CO2 phase behavior and pressure dynamics automatically maintain stable injection without external compression equipment. The pre-filled liquid CO2 and injection process leverage the inherent properties of CO2 to maintain stability.
Solution Approach 2:
The invention uses hydraulic principles by injecting liquid CO2 to create pressure and maintain flow stability. The liquid CO2 acts as a hydraulic medium that transmits pressure and maintains stable injection conditions, eliminating the need for mechanical compression equipment.
3Quantity of substance
If CO2 is injected as liquid or supercritical fluid to maximize storage density, then storage efficiency is improved, but phase change to gas occurs in low pressure reservoirs
Solution Approach 1:
Liquid CO2 is pre-injected into the tubing before the actual injection process. This preliminary action ensures that the CO2 remains in liquid phase throughout injection, preventing phase change to gas even in low pressure reservoirs. The pre-filled liquid CO2 maintains phase stability throughout the injection process.
Solution Approach 2:
A cushion of liquid CO2 is created beforehand in the injection tubing. This cushion prevents pressure drops that would cause phase change to gas, maintaining CO2 in the desired liquid or supercritical phase for maximum storage density throughout the injection process.
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 approach stabilizes the injection process, reduces the risk of CO2 deposition, and maintains a significant pressure head, enhancing the efficiency of CO2 injection and storage while minimizing the need for compressors and reducing injection costs.
Implementation Method 1
the phase behaviour of CO2 under low reservoir pressure conditions, e.g. as are typically associated with depleted gas fields... the injected CO2 may change into the gaseous state within the injection well, possibly within the injection tubing, if the pressure in the injection well falls to below the critical pressure for CO2
Implementation Method 2
the pressure head of this column will contribute to the downhole pressure... the pre-set pressure value being selected such that the CO2 in the injection tubing is maintained in a liquid or supercritical state
Data Source
AI summary
A method is described of injecting CO2 into an aquifer or a depleted hydrocarbon reservoir (211) via at least one injection well (202) that penetrates said aquifer or reservoir, wherein the injection well is provided with an injection tubing (203) that is in sealing engagement with the injection well. The injection tubing terminates at or immediately above the interval of the aquifer or the reservoir into which the CO2 is to be injected and the injection tubing is provided with a fluid injection control valve (208) at or near the bottom thereof which is closed or closes when the pressure above the valve is less than a pre-set pressure value and opens or reopens when the pressure above the valve is at or greater than said pre-set pressure value, the pre-set pressure value being selected such that the CO2 in the injection tubing is maintained in a liquid or supercritical state.