| Direct current field by oil extraction technology is widely used in oil and gas field,according to the characteristics of the coal reservoir medium under the electric field occurs,in this paper,the electric field real-time loading coal adsorption desorption gas characteristics are studied,aimed at exploring an effective incentive method,improvement of the existing drainage technology,has provided the new mentality for the selection of underground extraction method and theoretical support,guidance,efficient production of coal mine safety.Articles by adopting the combination of laboratory test and theoretical analysis method,on the basis of summarizing the predecessors’research,mainly explores the real-time loading electric field,different electric field intensity on the adsorption process and desorption process of coal impact characteristic,and through the test of coal sample electrical parameters and pore parameters,such as common modification mechanism of coal body under the electric field.The main research contents and achievements are as follows:（1）The study on the adsorption process of coal by real-time electric fiel d loading shows that the isotherm of CH4 and CO2 adsorption by coal is simil ar under different field intensities,and the adsorption capacity gradually decreas es with the increase of the applied electric field intensity,showing a linear dec rease relationship.The coal adsorption model in line with the electric field was established,and the fitting effect of the new model was above 0.99,which co uld accurately predict the adsorption response characteristics of coal under diffe rent field strengths.（2）The study on desorption and diffusion law of coal under real-time electric field loading shows that the response of desorption of CH4 and CO2 in coal is different and has certain differences.The desorption amount of CH4 in the coal body within 120min is greater than that without electric field,but the difference is small,while the influence characteristics of desorption CO2 in the coal body under the same condition are more obvious.In the same time,the change rule of CH4 dynamic diffusion coefficient of coal body is consistent,but it is mainly reflected in the 600s before gas diffusion.In this stage,the diffusion coefficient shows an exponential downward trend and changes quickly,and then the change of diffusion coefficient is basically the same.（3）It is found that the electric field can change the dielectric constant and resistivity of coal,and it shows a certain change rule.The dielectric constant is distributed in parallel layers with time,and increases linearly with the increase of the applied field intensity.The greater the electric field intensity is,the greater the dielectric constant is.Under the same conditions,the resistivity is on the contrary.With the increase of the electric field intensity under the loading,the resistivity of coal shows a linear downward trend.When the electric field is not added,the resistivity reaches the maximum and the decreasing range of different field intensities is also different.（4）Field on the modification mechanism of coal is mainly due to:electric effect,heating effect,induced polarization effect and hole crack effect from four aspects,and affected by the electric field on the one hand,improve the internal temperature of coal-gas system,reduces the role of coal and gas intermolecular potential,at the same time,reduced the coal surface adsorption potential well depth,the adsorption capacity decreased;On the other hand,the electric field changes the pore structure of coal body,connects the gas flow channel,and reduces the resistance in the gas diffusion process,which is the main reason for the electric field to inhibit adsorption and promote gas desorption. |
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