Characterization of radon gas transmission rate in pore structures of different rock layers by radon daughters inversion calculation.

Determining the transmission rate of radon gas in overburden strata is crucial for conducting a comprehensive study of radon gas's longitudinal and long-distance migration mechanisms. This study investigates the mineral components of rocks in the underground strata of the mining area using the X-ray diffraction method. Additionally, it examines the pore structure parameters of the rocks at different depths using the low-temperature nitrogen adsorption method.

Synergistic Mechanism of Ultrasonic-Chemical Effects on the CH Adsorption-Desorption and Physicochemical Properties of Jincheng Anthracite.

Ultrasonic is a new method to enhance coalbed methane recovery. A deeper comprehension of the synergistic mechanisms of combined ultrasonic-chemical modification on the CH adsorption-desorption capability and physicochemical properties of coal is necessary for potential field implementation, as the modification of coal reservoirs frequently necessitates the addition of chemical reagents. This paper evaluated the CH adsorption-desorption properties of anthracite modified by sodium dodecyl sulfate (SDS) solution, ultrasonic modification, and combined ultrasonic-SDS modification.

Characterization of Pore Structures with Mercury Intrusion Porosimetry after Electrochemical Modification: A Case Study of Jincheng Anthracite.

Quantitative characterization of the change in the cleat and pore structures and fractal dimensions in anthracite after electrochemical modification is crucial for better understanding of the modification effect. Thus, lump anthracite samples were electrochemically modified in our manufactured device with 0, 0.5, 1, and 2 V/cm potential gradients.

Response of Molecular Structures and Methane Adsorption Behaviors in Coals Subjected to Cyclical Microwave Exposure.

To better understand the methane adsorption behavior after microwave exposure, the importance of quantitatively characterizing the effect of cyclical microwave exposure on the molecular structures of coals cannot be overemphasized, with implications for enhancing coalbed methane (CBM) extraction. Thus, cyclical microwave exposure experiments of three different metamorphic coals were conducted, and the methane adsorption capacity before and after each microwave exposure (10 in total) for 120 s was evaluated. Fourier transform infrared spectroscopy analysis and peak fitting technology were applied to quantitatively characterize the changes in the structural parameters of coal molecules.

Pore Fractal Characteristics of Suancigou Long-Flame Coal after Electrochemical Treatment: An Experimental Study through the Implementation of N Adsorption and Mercury Intrusion Prosimetry Techniques.

The application of electrochemical treatment in coal seams for enhancing coalbed methane (CBM) recovery can also decrease the risks of outburst disasters. The long-flame coal samples were electrochemically modified with 0, 1, 2, and 4 V/cm electric potential gradients, and the pore structures were measured and analyzed by combined low-temperature nitrogen gas adsorption, mercury intrusion prosimetry, and fractal theory. The experimental test results indicated that the pore volumes of macropores (>50 nm) and mesopores (2-50 nm) increased after electrochemical modification and further increased with the increase in electric potential gradient.

Electrochemical Modification on CH and HO Wettability of Qinshui Anthracite Coal: A Combined Experimental and Molecular Dynamics Simulation Study.

The wettability of gas and liquid on the coal surface is one of the fundamental factors that affect the depressurization process during the coalbed methane (CBM) extraction. The wettability of coal surface changed after electrochemical modification, leading to the change in methane adsorption/desorption and water movement in coal reservoirs. Thus, the CH adsorption amount, desorption ratio, and coal-water contact angle of raw and modified anthracite samples were measured and simulated.

Effect of Cyclical Microwave Modification on the Apparent Permeability of Anthracite: A Case Study of Methane Extraction in Sihe Mine, China.

The application of cyclical microwave modification for accelerating the extraction of coalbed methane (CBM) from anthracite is limited. In this study, the apparent permeability of anthracite samples before and after each microwave treatment (three in total) for 120 s was measured by a self-built permeability-testing platform. Microcomputed tomography (micro-CT) technology and image-processing technology were employed to analyze the 3D micron-scale pore structures, especially the quantitative characterization of connected pores and throats.

Effects of Electrolyte pH on the Electro-Osmotic Characteristics in Anthracite.

Accelerating the drainage of water in coal reservoirs can significantly improve the extraction efficiency of coalbed methane (CBM). The movement of water with different pH values in anthracite was tested and analyzed. The results showed that the electro-osmotic flow velocity increased first and then slightly decreased with the increase of time up to 120 h.

Effect of Electric Potential Gradient on Methane Adsorption and Desorption Behaviors in Lean Coal by Electrochemical Modification: Implications for Coalbed Methane Development of Dongqu Mining, China.

The application of electrochemical modification for accelerating methane extraction in lean coal seams is limited due to the lack of experimental and theoretical research studies. Therefore, electrochemical modification with different electric potential gradient values was selected to modify lean coals in this study; meanwhile, the amount of methane adsorption and the methane desorption ratio were tested and analyzed. The results showed that the maximum amount of methane adsorption in coal samples decreased after electrochemical modification and the decrease in methane adsorption increased with an increase in electric potential gradient.

Effect of Pressure and Temperature on CO/CH Competitive Adsorption on Kaolinite by Monte Carlo Simulations.

The adsorption of CO and CO/CH mixtures on kaolinite was calculated by grand canonical Monte Carlo (GCMC) simulations with different temperatures (283.15, 293.15, and 313.

The Effect of Mg, Fe(II), and Al Doping on CH: Adsorption and Diffusion on the Surface of Na-Kaolinite (001) by Molecular Simulations.

Because kaolinite includes a large range of defect elements, the effects of Mg, Fe(II), and Al doping on the CH adsorption and diffusion on the surface of Na-kaolinite (001) were investigated by molecular simulations. The simulation results illustrate that ion doping can significantly reduce the amount of CH adsorbed by kaolinite, but the type of doped ions has little effect on the amount of adsorption. The specific surface area of kaolinite and the interaction energy between CH and the kaolinite's surface are two key factors that can determine CH adsorption capacity.

Experimental and mechanistic research on methane adsorption in anthracite modified by electrochemical treatment using selected electrode materials.

The strong adsorption capacity of methane in anthracite can seriously affect the methane extraction. Electrochemical treatment is an effective way to weaken the capacity of methane adsorption in coal. Iron, copper, aluminum and graphite as four kinds of electrode materials were selected to modify anthracite by electrochemical treatment.

Measurement and modeling of the adsorption isotherms of CH and CH on shale samples.

CH and CH are two common components in shale gas. Adsorption isotherms of CH, CH, and their binary mixtures on shale samples are significant for understanding the fundamental mechanisms of shale gas storage and the recovery of shale resources from shale reservoirs. In this study, the thermogravimetric method is applied to obtain the adsorption isotherms of CH, CH and their binary mixtures on two typical shale core samples.