Study On The Law Of Gas Desorption Of Coal With Different Metamorphic Degrees And The Sensitive Index Of Drilling Cuttings Gas Desorption

In order to study the pore structure of coal with different degrees of metamorphism on the adsorption control mechanism of coal body gas and the influence of coal drill cuttings gas desorption index,the gas adsorption law and pore composition of lignite coal in Anjialing coal mine,gas coal in Yushuling coal mine and anthracite coal in Duanshi coal mine were determined by constant temperature gas emission test and low-temperature liquid nitrogen adsorption method,and the pore structure characteristics and gas desorption rate of coal samples with different degrees of metamorphism were summarized and analyzed.The results showed that the gas desorption diffusion rate was greatly affected by the metamorphism degree and pore structure of the coal,the overall trend of gas desorption rate within the first10 minutes of Anjialing low-grade lignite coal was stable,the overall trend of gas desorption rate within the first 10 minutes of Yushuling low-end gas coal was stable,the gas desorption rate of Duanshi high-order anthracite coal was faster in the first 4min,and the trend of gas desorption rate within the last 6 minutes was stable.The correlation between Anjialing coal sample and Yushuling coal sample drill cuttings gas desorption index₁and gas pressure was??₂worse than that of drill cuttings gas desorption index,while the correlation between Duanshi coal sample drill cuttings gas desorption index₁and gas pressure was better than that of drill cuttings gas desorption index??₂.The analysis showed that the microporous structure determined the adsorption capacity of gas,and the development degree of mesopores and macropores determined the balance and rapid desorption capacity of gas adsorption,and there was a positive correlation between them,and the same coal body had the same desorption law,and the impact on??₂and₁was the same.??₂is more suitable as a low-rank coal outburst predictor,and₁is more suitable as a high-rank coal outburst predictor.This paper discusses the adsorption control mechanism of pore structure on coal gas from the microscopic level,which provides a theoretical basis for studying the law of coal gas desorption and diffusion,especially the sensitivity of coal drill cuttings.This paper has 63 figures,20 tables,and 135 references.