Adsorption behavior, including the thermodynamic characteristics of wet shales under different temperatures and pressures

et al. 2022

Adv. Geo-Energy Res.

Self Cite

Section: Introductionmentioning

confidence: 99%

Predicting adsorbed gas capacity of deep shales under high temperature and pressure: Experiments and modeling

Zhou

et al. 2022

Adv. Geo-Energy Res.

Self Cite

“…So, with the rise in temperature, the gas molecules move more violently, and the time they stay on the coal surface becomes shorter. Finally, it is easier to reach equilibrium within the specified time, which causes the limit gas adsorption amount of coal to decrease (Liang, 2000;Li et al, 2021). Figure 4 shows the limited adsorption capacity of soft coal and hard coal at different temperatures under 11 MPa pressure.…”

Section: Influence Of Temperature On Gas Adsorption Characteristics O...mentioning

confidence: 99%

“…In addition, the adsorption vacancy decreases and the adsorption rate decreases. When the pore surface that can pass through gas molecules is gradually and fully covered by gas molecules, the adsorption amount does not increase with the increase of pressure, and the adsorption reaches equilibrium (Li et al, 2021).…”

Section: Influence Of Pressure On Gas Adsorption Characteristics Of C...mentioning

confidence: 99%

Study on the Pore Structures and Adsorption Characteristics of Coking Coal of Liulin Mining in China Under the Condition of High Temperature and High Pressure

Peng

et al. 2022

Front. Earth Sci.

In order to study the change of pore structure and adsorption characteristics of coking coal after the high-temperature and high-pressure adsorption test, the coking coal from the Liulin coalmine was selected for the research. Both the mercury injection experiments were carried out on the raw coal and the coal after the isothermal adsorption experiment processing with a pressure of 11 MPa and temperature ranging from 30 to 90°C. The results show that the pressure is beneficial to gas adsorption, while the temperature has a restraining effect on the gas adsorption of coking coal, and there is a good negative exponential relationship between the adsorption capacity and temperature. The hysteresis loop of that after the high-temperature and high-pressure isothermal adsorption test is smaller than that of raw coal, and the connectivity of pores becomes worse. In the process of the mercury injection experiment, the hysteresis loop of coking coal after the high-temperature and high-pressure adsorption experiment is smaller than that of raw coal. This demonstrates that the open pores decrease and the semi-closed pores increase, and then the connectivity of the pores becomes worse, which is not conducive to the gas flow when the coking is subjected to high-temperature and high-pressure action. After the high-temperature and high-pressure adsorption experiment, the volume of macropores, visible pores, and crannies of the coking coal decreases, and the volume of micropores and minipores increases. However, the total pore volume reduced overall. Under the same pressure, with the increase in temperature, the volume of macropores, visible pores, and crannies increases, while the volume of micropores and minipores decreases, and the total pore volume increases. After the high-temperature and high-pressure adsorption experiment, the proportion of micropores and minipores increases, and the specific surface area also increases. Under the same pressure, the surface areas of micropores and minipores decrease and the total specific surface area also decreases with the increase in temperature.

“…In addition, the water absorption of clay minerals may be one of the reasons. Although the adsorption experiments in this study were conducted under a drying condition, part of the water bound in the clay minerals still exists [60,61]. Moisture can directly reduce the adsorption capacity of clay pores because water molecules can reduce the number of potential adsorption sites by blocking micropores or directly occupying polar adsorption sites [62].…”

Section: Effect Of Mineral Composition On Adsorption Capacitymentioning

confidence: 99%

Clarifying the Effect of Clay Minerals on Methane Adsorption Capacity of Marine Shales in Sichuan Basin, China

Zhou

Zhang³

et al. 2021

Energies

The effect of clay minerals on the methane adsorption capacity of shales is a basic issue that needs to be clarified and is of great significance for understanding the adsorption characteristics and mechanisms of shale gas. In this study, a variety of experimental methods, including XRD, LTNA, HPMA experiments, were conducted on 82 marine shale samples from the Wufeng–Longmaxi Formation of 10 evaluation wells in the southern Sichuan Basin of China. The controlling factors of adsorption capacities were determined through a correlation analysis with pore characteristics and mineral composition. In terms of mineral composition, organic matter (OM) is the most key methane adsorbent in marine shale, and clay minerals have little effect on methane adsorption. The ultra-low adsorption capacity of illite and chlorite and the hydrophilicity and water absorption ability of clay minerals are the main reasons for their limited effect on gas adsorption in marine shales. From the perspective of the pore structure, the micropore and mesopore specific surface areas (SSAs) control the methane adsorption capacity of marine shales, which are mainly provided by OM. Clay minerals have no relationship with SSAs, regardless of mesopores or micropores. In the competitive adsorption process of OM and clay minerals, OM has an absolute advantage. Clay minerals become carriers for water absorption, due to their interlayer polarity and water wettability. Based on the analysis of a large number of experimental datasets, this study clarified the key problem of whether clay minerals in marine shales control methane adsorption.