Shale gas desorption pressure tester

Abstract

The invention provides a shale gas desorption pressure tester. The tester mainly comprises a cylinder body, a base, an upper cover, a high-pressure micropump and a pressure sensor, wherein a glass observing window is arranged on the cylinder body; the pressure sensor is installed on the upper cover; a liquid inlet is formed in the central position of the upper cover; the upper cover is connected with the high-pressure micropump. Saturated brine with temperature consistent with the formation temperature is continuously added to the cylinder body in which shale cores are put and the value of pressure in the cylinder body immediately rises, linear bubbles generated in quantity because of desorption escape of adsorbed shale gases adsorbed on the surface of shale and in micropores can be observed from the observing window, when the linear bubbles begin reducing, the corresponding pressure value is the initial shale gas desorption pressure, and when the linear bubbles begin reducing in quantity, the corresponding pressure value is the main shale gas desorption pressure. The shale gas desorption pressure tester has the beneficial effects that adopting the direct measurement mode, compared with the prior art, the tester is more reliable and accurate in data, also has the effect of greatly shortening the experimental determination time and provides powerful guarantees for shortening the project period and ensuring the technology and economical efficiency of exploitation.

Description

technical field [0001] The invention relates to a shale gas desorption pressure tester. Background technique [0002] Shale gas refers to the natural gas in organic-rich mud shale and interlayers. The shale gas extracted from shale is mainly free and adsorbed, accounting for about 50% each, and only a very small amount is stored in cheese in a dissolved state. Roots, asphaltenes and petroleum. Unlike conventional oil and gas, shale gas does not form traps, and horizontal wells and large-scale hydraulic fracturing are required for economical exploitation. During the exploitation process, when shale is broken by hydraulic fracturing, free shale gas will escape first. Then, as the fracturing pressure decreases, the adsorbed shale gas adsorbed on the shale surface and in the interlayer begins to desorb and enter the gas production channel. Therefore, the desorption pressure calculation and test are very important in shale gas development , which directly affects the technology...

AI Technical Summary

Problems solved by technology

[0008] Aiming at the deficiencies of the prior art, the present invention provides a shale gas desorption pressure tester, which uses a direct experimental method to measure the shale gas desorption pressure, replacing the indirect calculation method commonly used in the prior art, and is easy to operate and high in measurement efficiency , the measured data is accurate, which solves the technical problems of shale gas isothermal adsorption experiments such as long cycle, low efficiency, and inaccurate data, and provides a strong guarantee for the smooth implementation of the project

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