A method for testing and analyzing gas adsorption isotherms of rocks under different water content conditions

Abstract

The invention belongs to the field of petroleum and chemical scientific research technology. Aiming at the problems of water saturation change, uncertainty and high water saturation conditions in the current rock water content gas isothermal adsorption test method, the invention proposes a rock with different water content conditions. The lower gas adsorption isotherm test and analysis method, on the basis of the existing method, through the use of multiple tests of one saturation and the measurement of mass change before and after vacuuming before the test to correct the water saturation and dead volume, and calculate the corrected adsorption isotherm Line I i A series of links, such as the calculation of water saturation changes caused by vacuum treatment before the test, can continuously carry out isothermal adsorption tests on rock samples with different water content conditions, increase the upper limit of water saturation that can be tested, and improve the corresponding water content of the measured adsorption isotherm. The degree of accuracy of saturation can realize a wider range, rapid and accurate analysis of the influence of water saturation on the change of rock gas adsorption performance.

Description

Technical field [0001] The present invention belongs to the field of petroleum and chemical research, involving rock test techniques for gas adsorption amount, and more particularly to a gas adsorption isotherm test analysis method under different water conditions of rock. Background technique [0002] The rock gas refers to the natural gas retained in the hydrocarbon source rock after formation, and the main component is methane. Gas shale generally nano-pore development, has a high specific surface, and the gas adsorbed onto the pore wall (generally referred to as adsorbing gas) is not negligible to the total amount of shale. Studies have shown that the proportion of suction gas in shale gas can reach 20% to 80%. The carried out adsorption experiments also showed that the amount of adsorption of methane was changed with the temperature pressure. Isothermal adsorbing test techniques are common technologies for evaluating adsorbents (such as shale) on adsorption (e.g., methane) a...

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Problems solved by technology

[0023] Aiming at the problems of water saturation change, uncertainty and high water saturation conditions existing in the current rock water content gas isotherm adsorption testing method, the present invention proposes a gas adsorption isotherm test and analysis method under different rock water content conditions. On the basis of the existing method, by adding a series of links, the calculation of the water saturation change caused by the vacuum treatment before the test can be realized, and the isothermal adsorption test of rock samples with different water content conditions can be continuously carried out, and the upper limit of the testable water saturation can be increased, and the obtained The accuracy of the measured adsorption isotherm corresponding to the water saturation, to achieve a wider range, rapid and accurate analysis of the influence of water saturation on the rock gas adsorption performance

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