Liquid nitrogen pressurizing device, anti-reflection experiment system using same and experiment method

Abstract

The invention discloses a liquid nitrogen pressurizing device which comprises a liquid nitrogen container, an electric control device, a top cover and a liquid nitrogen tank used for pressurizing liquid nitrogen, and the electric control device is connected with a display screen. The invention further discloses an anti-reflection experiment system using the liquid nitrogen pressurizing device. Theanti-reflection experiment system comprises the liquid nitrogen pressurizing device and a confining pressure system. The invention also discloses an experiment method using the anti-reflection experiment system. The experiment method comprises the following steps: step one, system inspection; step two, putting a coal sample; step three, applying predetermined circumferential pressure and axial pressure to the coal sample; step four, vacuumizing a nitrogen supply inner pipe; step five, injecting liquid nitrogen into a liquid nitrogen thermal preservation cavity; and step, injecting high-pressure liquid nitrogen into the coal sample to carry out a cracking and anti-reflection experiment. According to the device, adverse effects caused by liquid nitrogen evaporation in the nitrogen supply pipeline are greatly relieved, the technical cost is reduced, and it is guaranteed that a liquid nitrogen fracturing anti-reflection experiment is conducted on the coal sample stably and smoothly.

Description

technical field [0001] The invention relates to the technical field of coal bed gas exploitation, in particular to liquid nitrogen pressurized fracturing anti-permeability technology. Background technique [0002] The air permeability coefficient of coal seams in my country is low, and gas drainage is difficult, so there is an urgent need for pressure relief and permeability enhancement methods. The pressure relief and permeability enhancement methods mainly include loosening blasting, intensive drilling, deep hole pre-splitting, mining protective layer, and hydraulic punching. At present, liquid nitrogen fracturing anti-reflection technology needs to be developed. Liquid nitrogen fracturing is an environmentally friendly and relatively cheap fracturing method. There are many published liquid nitrogen rapid fracturing methods, such as using a booster pump to Nitrogen boost. Existing liquid nitrogen rapid fracturing technologies all have the defect of slow pressure increase ...

AI Technical Summary

Problems solved by technology

Existing liquid nitrogen rapid fracturing technologies all have the defect of slow pressure increase of liquid nitrogen, and it is difficult to avoid a large amount of gasification of liquid nitrogen in the fracturing pipeline, which will bring adverse effects to liquid nitrogen fracturing. Therefore, it is urgent to develop a method to greatly reduce the vaporization of liquid nitrogen during transportation

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