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The Soochow University Beamline, located at the National Synchrotron Radiation Laboratory in China, is a Soft X-ray beamline designed for studying energy-related materials and devices. It operates in the energy range of 45 eV–1100 eV and is specifically tailored for investigating Li, B, C, N, O, F K-edges, and most L-edges of transition metals. The beamline offers various capabilities, including X-ray absorption, photon in photon out, and in situ/operando studies of energy materials and devices in gas/liquid environments. It has been successful in producing high-quality research papers and is open to users worldwide. The beamline is a collaborative effort between Soochow University and the National Synchrotron Radiation Laboratory, with funding from Soochow University. It is the first synchrotron radiation beamline in China to be funded by a university. [Extracted from the article]

Gas injection into coal seams is gaining increasing attention for improving coalbed methane (CBM) production. This technical development requires detailed and reliable information on gas adsorption/desorption-induced deformation and gas occurrence mechanisms. Hence, in this paper, high volatile bituminous coal was taken as the experiment samples from northern Shannxi Province, China, and adsorption-induced swelling experiments with CO 2 and N 2 were carried out under the conditions of one-time injection and step-by-step injection. Then, based on adsorption-induced swelling characteristics, a thermodynamic model was further established to disclose the adsorption/desorption-induced deformation mechanism of confined coals. Results showed that the swelling/shrinkage strain curves of CO 2 and N 2 adsorption/desorption in the coal matrix were generally divided into four stages, including pressurization-deformation, adsorption-induced swelling, depressurization-deformation, and finally desorption-induced shrinkage. It can be seen that the coal swelling effect caused by N 2 adsorption was far less than that caused by CO 2 adsorption. However, both CO 2 and N 2 adsorption displayed that the apparent volumetric swelling weakened with increasing strain when compared with the same adsorption pressure under different strain conditions. In contrast, the absolute volumetric swelling of the confined coal was a coupling result from adsorption-induced swelling and pore pressure effects. Further, based on the thermodynamic model, it was verified that the adsorbate type, the chemical potential of the adsorbate molecule and stress conditions are key factors affecting adsorption-induced swelling of coal under a certain temperature and pressure. In addition, a desorption lag phenomenon during the desorption-induced shrinkage stage was observed, due to incomplete gas desorption and gas retention in the coal macromolecular network. It was also found that there was a shrinkage phenomenon after the peak strain during gas adsorption. That is to say, when fixed adsorption sites on the coal pore surface reached the adsorption saturation state at the peak strain, gas molecules would be stored in an absorption state in the coal macromolecular network under continuous adsorption. These phenomena further explained coal swelling and gas occurrence mechanisms. • Swelling/shrinkage strain curve can be generally divided into four stages. • Absolute volumetric swelling is controlled by adsorption swelling and pore pressure. • Thermodynamic model reflects Gibbs free energy of gas adsorption in coal decreases. • Adsorption-induced swelling effect tends to be dropped with increasing stress. • Shrinkage effect after peak strain and desorption lag are occurred in whole process. [ABSTRACT FROM AUTHOR]

Using Isothermal Adsorption/Desorption System Model 15-100 and Electrohydraulic Servo Rock System Model MT5815 as the main apparatuses and collecting samples from the major coal reservoirs in the south of Qinshui Basin, a hot point region of coalbed methane exploration, the paper carries out systematical comparisons of the isothermal adsorption experimental data for injection water coal samples, equilibrium moisture samples and dry coal samples, probes and establishes an experimental method of injection water coal sample preparation and isothermal experiment to simulate real reservoir conditions, and then summaries the experimental regulations and discusses the mechanism of liquid water influencing coal methane adsorption. Results of the experiment indicate that: The Langmuir volume of injection water coal samples is notably larger than that of equilibrium moisture samples, as well as larger than or equivalent to that of dry coal samples; the Langmuir pressure of injection water coal samples is the highest, the next is equilibrium moisture samples, while the dry samples is the lowest, of which the experimental results of injection water samples to simulate real reservoir conditions are more close to the fact. Under the conditions of in-position reservoirs, liquid water in coals has evident influence on methane adsorption ability of coal matrix, which can increase the adsorbability of coal and make the adsorption regulation fit to Langmuir model better. Its major reason is the increase of wetting coal matrix adsorbability. The above experimental results overthrow the conventional cognition that liquid water has no influence on coalbed methane adsorption, which may lead to an improvement of the coalbed methane isothermal adsorption experimental method and of the reliability of coalbed methane resource evaluation and prediction. [ABSTRACT FROM AUTHOR]

Using salt caverns for an underground strategic petroleum reserve (SPR) is considered as an ideal approach due to the excellent characteristics of low porosity, low permeability, self-healing of damage, and strong plastic deformation ability of rock salt. Salt deposits in China are mostly layered rock salt structures, with the characteristics of many interlayers, bringing great challenges for the construction of SPR facilities. Studying the microscopic pore characteristics of the rock surrounding SPR salt caverns in different environments (with brine and crude oil erosion) is necessary because the essence of mechanical and permeability characteristics is the macroscopic embodiment of the microscopic pore structure. In this paper, XRD tests and SEM tests are carried out to determine the physical properties of storage media and surrounding rock. Gas adsorption tests and mercury intrusion tests are carried out to analyze the microscopic pore structure, specific surface area variation and total aperture distribution characteristics of SPR salt cavern host rock. Results show that: (1) Large numbers of cores in interlayer and caprock may provide favorable channels for the leakage of high-pressure crude oil and brine. (2) The blockage of pores by macromolecular organic matter (colloid and asphaltene) in crude oil will not significantly change the structural characteristics of the rock skeleton, which is beneficial to the long-term operation of the SPR salt cavern. (3) The water–rock interaction will bring obvious changes in the micro-pore structure of rock and increase the leakage risk of the storage medium. The results can provide theoretical bases and methods for the tightness analysis of China's first underground SPR salt cavern. [ABSTRACT FROM AUTHOR]