Experimental investigation and analysis on the changing characteristics of the gas flow capacity of coal in CO2-ECBM and N2-ECBM
we have added experimental data both pressure hysteresis (fig. 4) and core flood experiment (N2 and CO2) in there. Note that we have just provided the classical sample data due to the other data need to be contained in the future study.
Steps to reproduce
a) The sample was vacuumed to remove residual gas. b) A grads load pattern was applied to both the confining pressure and gas pressure, after achieving the setting target value, allowing the gas adsorption to equilibrate. c) Afterward, the pipework was transported to connect N2 or CO2, and the injection pressure was maintained to begin the core flood experiment. d) The gas sample was collected using a gas sampling bag and analyzed by a gas chromatograph; the experiment was terminated when steady-state concentration conditions were achieved. Three types of pure gas (99.99%) were applied in the core flooding experiment at an injection pressure of 3 MPa with a confining pressure of 4 MPa. In addition, by the opening control method, the downstream gas pressure was maintained at 2 MPa, which was approximately equal to the preadsorption equilibrium pressure, and the opening degree of the outlet valve was generally constant during the test. Moreover, the water bath temperature was 25° in order to be representative of the reservoir condition. The average testing value to the void volume of the pipeline was 50 mL.