Method for accurately measuring absorbed phase density of methane on shale

Abstract

The invention relates to a method for accurately measuring absorbed phase density of methane on shale. The method comprises the following steps: 1) smashing a piece of shale sample to be 60-80 meshes, and dividing the powder into two; 2) performing a volumetric method isothermal adsorption experiment on the first shale sample, and obtaining a calculation model of the amount n, adsorbing CH4, of the adsorbed state methane substance; 3) performing a weight method isothermal adsorption experiment on the second shale sample, and obtaining a calculation model of the mass m, adsorbing CH4, of the adsorbed state methane; 4) performing adsorbed phase volume correction on the calculation model of the amount n, adsorbing CH4, of the adsorbed state methane substance, obtained in the step 2) and the calculation model of the mass m, adsorbing CH4, of the adsorbed state methane, obtained in the step 3), so as to obtain the corrected substance amount calculation model and the corrected mass calculation model of the adsorbed state methane; 5) according to a definition formula of the amount of substance, combining with the two calculation models in the step 4), and determining the mass m, adsorbing CH4, and the volume V adsorption of the adsorbed state methane; 6) according to the definition of the density, determining an exact adsorption value of the adsorbed phase density rho of methane on the shale.

Description

technical field [0001] The invention relates to a method for accurately measuring the adsorption phase density of methane on shale, and belongs to the technical field of geological exploration. Background technique [0002] When domestic and foreign scholars study the adsorption properties of coal-measure mudstone and shale, most of them use volumetric isothermal adsorption instruments. Accepted by foreign scholars, the latter uses a magnetic levitation balance as the main detection tool, and the test results are more accurate. [0003] When studying the isothermal adsorption characteristics of coal-measure mudstone and shale by the volumetric method, scholars at home and abroad found that when using the volumetric method to test the methane adsorption of shale, the existence of the adsorption phase volume will reduce the volume of free gas in the sample pool. , which in turn affects the test results of shale adsorption capacity. However, the existence of the volume of the...

AI Technical Summary

Problems solved by technology

This method combined with the isothermal adsorption model to optimize the adsorption phase density, the accuracy of the evaluation results of the adsorption phase density will largely depend on the applicability of the isothermal adsorption model, and the shale pore structure is complex, isothermal The applicability of the adsorption model is difficult to determine, so the evaluation results obtained by using this method need further study

[0005] In summary, previous studies on the density of adsorbed phases are still in the stage of theoretical assumptions or mathematical optimization, and have not been accurately tested from the experimental point of view. However, the research results of different scholars vary greatly, and there is no conclusion, which will definitely affect the objective evaluation of rock The ability to adsorb gas has a greater impact

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