Pulsed CO2 Displacement Testing for Real-Time Methane Replacement
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Solution Overview
Problem
Existing devices for the displacement and replacement of methane (CH4) with carbon dioxide (CO2) in unconventional natural gas reservoirs, such as CBM and shale, take a long time and cannot reflect the dynamic displacement process in real time, failing to clarify the relationship between displacement evaluation indicators and time.
Innovation Solution
An experimental system comprising a gas supply system, pulse control system, reservoir environment simulation system, data acquisition and processing system, and tail gas recovery system, which converts CO2 into pulsed gas to shorten displacement time, records experimental data in real time, and processes it to reflect the dynamic displacement process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If steady-state displacement and replacement of CH4 with CO2 is used, then the displacement process can be simulated, but the displacement time is very long and the dynamic displacement process cannot be reflected in real time
Solution Approach 1:
The patent applies periodic action by using pulsed CO2 injection instead of continuous steady-state injection. The pulse control system generates periodic pressure pulses that drive CO2 through the core sample, creating a dynamic displacement process that achieves both real-time monitoring and reduced displacement time. The pulsed flow regime allows the system to capture dynamic displacement characteristics while maintaining experimental feasibility.
Solution Approach 2:
The patent transitions from static steady-state conditions to dynamic pulsed conditions. The pulse control system introduces time-varying pressure fluctuations that create dynamic flow patterns, enabling the system to reflect the actual dynamic displacement process in real time while significantly reducing the overall displacement time compared to traditional steady-state methods.
2Loss of information
If existing displacement devices are used, then the final displacement indicator can be obtained, but the relationship between displacement evaluation indicator and displacement time cannot be clarified
Solution Approach 1:
The patent implements feedback mechanisms through real-time data acquisition and monitoring systems that continuously measure displacement indicators during the pulsed CO2 injection process. The system captures time-resolved data on gas flow rates, pressure changes, and methane displacement progress, enabling the establishment of quantitative relationships between displacement evaluation indicators and displacement time that were previously inaccessible with steady-state methods.
Solution Approach 2:
The patent introduces a pulse control system as an intermediary between the CO2 injection system and the core sample. This intermediary device generates controlled pressure pulses that create dynamic flow conditions, serving as a mediator that enables both real-time monitoring of the displacement process and efficient experimentation. The pulse control system transforms static injection into dynamic pulsing, revealing the time-dependent behavior of methane displacement.
3Adaptability or versatility
If CO2 is injected into the stratum to displace and replace oil gas, then the emission of CO2 in the atmosphere can be reduced and the stability of an oil gas reservoir is maintained, but the development technology is not mature and the replacement effect under different geological backgrounds has not been quantitatively evaluated
Solution Approach 1:
The patent employs parameter changes by systematically varying injection pressure, pulse frequency, and gas composition ratios in the experimental system. These controlled parameter variations allow the research to evaluate CO2 replacement effects under different simulated reservoir conditions, including variations in permeability, saturation, and geological characteristics. The ability to adjust and control experimental parameters enables quantitative assessment of replacement effectiveness across diverse geological backgrounds, advancing technology maturity while maintaining adaptability.
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 system and method enable real-time monitoring and analysis of the displacement process, accurately determining the relationship between displacement evaluation indicators and time, improving the efficiency and recovery rate of CH4 displacement with CO2.
Implementation Method 1
The adsorption capacity of CO2 on shale and coal rock is greater than that of methane (CH4), and when CO2 is injected, the CH4 replacement efficiency can be effectively improved
Implementation Method 2
the pulse control system provides a pulse for the gas source to convert a gas passing through the pulse control system into a pulsed gas
Implementation Method 3
the data acquisition and processing system records in real time, analyzes and processes an experimental data of the reservoir environment simulation system
Data Source
AI summary
An experimental system for a pulsed displacement and replacement of methane with carbon dioxide is provided. The experimental system includes a gas supply system, a pulse control system, a reservoir environment simulation system, a data acquisition and processing system and a tail gas recovery system, connected in sequence; and the carbon dioxide output from the gas supply system is converted into a pulsed gas through the pulse control system, the pulsed gas enters the reservoir environment simulation system to shorten a time of displacing and replacing methane with carbon dioxide, the experimental data of the reservoir environment simulation system is recorded in real time, analyzed and processed by the data acquisition and processing system, a dynamic displacement process is reflected in real time, and a relationship between a displacement evaluation indicator and a displacement time is clarified. The disclosure further provides an experimental evaluation method, using the above experimental system.