Apparatus for measuring diffusion coefficient of carbon dioxide in rock

Abstract

The invention relates to an apparatus used for measuring the diffusion coefficient of carbon dioxide in rock. The apparatus comprises an apparatus housing. A gas tank, a diffusion cylinder and a fluid tank are arranged vertically in parallel in the apparatus housing. A gas pipeline and a liquid pipeline are arranged outside the apparatus housing. The inlet of the gas pipeline is connected to a carbon dioxide cylinder through a booster pump. A four-way valve is arranged in series on the gas pipeline. The gas outlets of the four-way valve are respectively connected to the four-way valve, the gas tank, and a pressure sensor. The inlet of the liquid pipeline is connected with a sample tank. A four-way valve is arranged in series on the liquid pipeline. The liquid outlets of the four-way valve are respectively connected to the four-way valve, the fluid tank, and a pressure sensor. According to the invention, a gas chamber is eliminated fundamentally, and the influence caused by sampling upon the gas pressure is eliminated. Vacuum pumping, saturated formation fluid and the determination of gas diffusion coefficient are integrated. Therefore, the influences on the saturated fluid in rock during the vacuum pumping process are completely eliminated.

Description

technical field [0001] The invention relates to a device for measuring the diffusion coefficient of carbon dioxide in rocks, belonging to the technical field of petrochemical industry. Background technique [0002] As the main greenhouse gas, carbon dioxide emission reduction has become a hot issue in the world today. Scientists have shown that geological storage is an effective way to reduce carbon dioxide emissions. However, when carbon dioxide is stored geologically, the choice of geological storage sites is particularly important. This is because on-site operators, environmental regulators, and the public all want to ensure that carbon dioxide is stored safely in geological storage, ensuring that the carbon dioxide will not exceed the predetermined boundary in the ground and will not leak into the atmosphere again. Therefore, it is particularly important to evaluate the safety of the storage site before the geological storage of carbon dioxide. [0003] When carbon dio...

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Problems solved by technology

This type of method requires real-time sampling of the gas chambers at both ends of the rock, and then gas chromatographic analysis of the gas samples at each time point to calculate the change in gas concentration at both ends of the rock, so that the gas chambers at both ends of the rock will be analyzed at the instant of sampling. The influence of pressure, which affects the measurement accuracy

And because two gas chambers need to be installed at both ends of the rock, when it is necessary to measure the diffusion coefficient of gas in the rock saturated with formation fluid, the saturated formation fluid will be lost during the vacuuming process, which affects the relationship between the experiment and the real conditions of the formation. identity

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