利用核磁共振技术评价煤层吸附能力

Evaluation on Absorption Capacity of Coal by NMR

为研究煤层吸附能力,选取鄂尔多斯盆地神府区块煤岩样品,开展等温吸附、核磁共振和低温液氮吸附联合实验。核磁共振T2谱和低温液氮吸附实验都可以有效地反映煤岩的孔隙分布,利用两者之间的相关性,将核磁共振T2谱转化为孔隙分布图谱;在此基础上,利用核磁共振T2谱计算小于10nm的微孔隙体积,研究与等温吸附参数的相关关系;进一步将微孔隙体积转换为标准状况下体积,与煤岩样解析出的气体量对比分析。研究结果显示,该方法对煤层吸附能力具有良好的评价效果。

In order to study the absorption capacity of coal,typical coal and rock samples are selected for isothermal absorption,nuclear magnetic resonance and low temperature liquid nitrogen experiments.Nuclear magnetic resonance T2 distribution and low temperature liquid nitrogen can effectively reflect the pore distribution of coal,and with the correlation,the T2 distribution can be translated into pore throat distributions.On the basis,the relationship between the microporous volume less than 10 nm which is calculated by the T2 distribution and the isothermal adsorption parameters is further studied.The volume of the micropores is further converted to the volume under standard conditions and is contrasted by the amount of gas desorbed from the coal.The results show that the method is good for absorption capacity evaluation.