页岩气吸附解吸规律研究

On the Adsorption and Desorption Trend of Shale Gas

页岩中天然气的吸附解吸规律是页岩气开发的基础。根据物质平衡原理,自行设计了页岩气吸附解吸实验装置。用该装置对取自鄂尔多斯盆地的三个页岩岩样在不同温度(30～90℃)、不同压力(0.1～10MPa)条件下,进行页岩气吸附及解吸规律研究。实验结果表明,吸附量随有机碳含量的增加而增大;随压力的增加吸附量增大,而随温度的增大吸附量减小。同一温度压力条件下,相对吸附过程而言,解吸过程有滞后现象,解吸不够彻底。对粘土含量较大的页岩,朗格缪尔模型拟合效果较差,而利用修正的双朗格缪尔模型可以得到较好的拟合结果。

Regular pattern of gas adsorption and desorption in shale is the foundation of shale gas development.An experimental device for measuring shale gas absorption and desorption was self-developed according to material balance principle.Adsorption and desorption trend of 3 shale samples from Ordos basin were measured on this device at different temperature（30℃ to 90℃） and under different pressure（0.1 MPa to 10 MPa）.Results show that adsorption increases along with the total organic carbon content in shale.Adsorption of methane increases along with the pressure but decreases with the temperature.At the same temperature and under same pressure,desorption process lags behind adsorption,and is not full enough.The observed adsorption was fitted by using Langmuir isotherm adsorption model.Results show that the fitting effect is poor for shale with larger clay content.But better fitting results can be obtained by using revised double Langmuir model.