A method to detect co in porous media using ct technology 2 Diffusion method

Abstract

The present invention belongs to the technical field of natural gas resource development and CO2 emission reduction, and is characterized in that: the device mainly includes a CT (computed tomography) system, a fluid injection system, a gas analysis system and a data acquisition and processing system, a high pressure resistant sand filling stone core tube is arranged in a CT instrument in the CT system, according to the method, CT is used for real-time measuring of density change of a fluid in a porous media, by combination of CO2-CH4 mixture state equation, concentration change distribution of the components in the porous media can be obtained, and on the basis of theory of convective diffusion, by use of finite difference method, the dispersion coefficient in the porous media can be directly obtained. The effects and benefits are that: the CT instrument can be used for nondestructive and real time measurement of micro-pore structure and density change of the fluid in the porous media for further obtaining the dispersion coefficient in the porous media, visually and quantitatively descript CO2-CH4 dispersion process in the porous media, and more accurately revealing the CO2-CH4 dispersion process rule in the porous media.

Description

technical field [0001] The invention belongs to natural gas resources development and CO 2 In the field of emission reduction technology, it specifically relates to a method for detecting CO in porous media using CT technology. 2 Apparatus and method of dispersion. Background technique [0002] Natural gas (mainly composed of CH 4 ) is a clean, efficient, and environmentally friendly high-quality energy, which is conducive to reducing pollutant emissions. Based on the needs of environmental protection and social development, my country's demand for natural gas is increasing year by year. At the same time, due to the extensive use of fossil fuels such as coal and oil, the main greenhouse gas CO in the atmosphere 2 Concentrations are increasing, causing global warming. Thus improving clean energy supply and reducing CO 2 Emissions became a concern. [0003] CO 2 Enhanced natural gas recovery technology, which refers to the injection of CO 2 To the bottom of the deplet...

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Problems solved by technology

[0004] Currently for CO 2 CO in enhanced natural gas recovery technology 2 -CH 4 There are relatively few studies on the diffusion process, and the existing studies are mainly on the CO 2 -CH 4 Diffusion coefficient measurements, and the CO 2 -CH 4 The traditional research on the measurement of dispersion coefficient mainly stays in the gas analysis and measurement of the gas produced at the outlet of the experimental system, and then solves the dispersion coefficient and analyzes the dispersion process through the convective dispersion theory. The influence of the road effect and the inlet and outlet effect on the measurement of the dispersion coefficient in porous media, the obtained dispersion coefficient generally has a large deviation

In addition, visualization studies on the diffusion process are scarce, although some researchers have carried out CO 2 -CH 4 The visualization study of the dispersion process, but it mainly presents the macroscopic density distribution inside the core, neither can give the microscopic pore structure inside the porous medium, nor can it obtain the CO2 density in the porous medium. 2 -CH 4 Diffusion coefficient, its dispersion coefficient is also obtained according to the traditional method, including the overall diffusion coefficient including pipeline effect and inlet and outlet effects

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