Coal pores are the locations of coalbed methane occurrence and enrichment main storage space targeted in CO2 sequestration. The systematic investigation coal pore structure its development is great significance to provide insights into generation, mine gas outburst mechanisms, seam In this study, testing technologies methods, classification characteristics their control factors were systematically investigated summarized. results show that direct test indirect fluid injection X-ray...

CO2/N2-enhanced coalbed methane recovery is an important means of increasing production, and understanding the competitive adsorption CO2, CH4 N2 in coalbeds its impact on coal properties important. A structural model for anthracite from Daning-Jixian was constructed based elemental analyses, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy carbon nuclear magnetic resonance data. The grand canonical Monte Carlo method used to research multiple gases changes porosity...

The isothermal adsorption of methane in coal is essential for understanding the mechanism. accuracy equilibrium measurements directly impacts reliability and scientific validity experimental results. This study conducted high-pressure adsorption/desorption experiments on samples with varying pore structures to investigate impact evaluation method found that using fixed-time determine volume can lead significant errors, particularly complex fluctuations curves. Based observed behavior curve,...

Coalbed methane (CBM) is a green unconventional energy source where the gas diffusion efficiency in coal directly limits production capacity. Therefore, different adsorption experiments were used to determine characteristics of samples with varying degrees metamorphism. The influence law based on type, pore structure, and sample size coefficient was analyzed, synergistic control effect various factors discussed. results show that when particle same, gases shows change rule CO2 > N2 CH4,...

In China, the capacity to produce coalbed methane and extract underground gas is restricted by prevalence of low-permeability coal seams. Liquid nitrogen fracturing a new low temperature-high-pressure anhydrous technology that uses temperature high frost heave forces increase permeability. To better understand liquid effect on coal, we conduct freeze-thaw cycle (LNCFT) experiments different rank coals from Qinghai, Shanxi, Shaanxi provinces. We combined low-pressure carbon dioxide adsorption...

Quantitative real-time reverse transcription-polymerase chain reaction (qRT-PCR) is the most commonly used and powerful method for gene expression analysis due to its high sensitivity, specificity, throughput, accuracy of this approach depends on stability reference genes normalization. Taihangia rupestris Yu & Li (Rosaceae), an andromonoecious plant, produces both bisexual flowers unisexual male within same individual. Using qRT-PCR technique, investigation profiling in staminate perfect...

The overall fracturing stimulation effect using quartz sand as a proppant is poor, resulting in no breakthrough the production of coalbed methane (CBM) wells low permeability coal reservoir Lu'an Mining Area. In this study, mixed coated ceramsite three particle sizes (40–60, 16–40, and 12–20 mesh) was selected to conduct hydraulic field experiment on CBM wells, located near fractured with study area. drainage effects size-coated area were compared. results show that cumulative gas from well...

Porosity in coal is the main space and migration channel for coalbed methane, more than 90% of specific surface area comes from ultramicropores (<1.1 nm), which are expected to be affected by metamorphic deformation processes tectonically deformed (TDC). It important know how occur evolve safe mining methane development. In this work, we employ low-pressure CO2 adsorption at 273 K (LPCO2), X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM) techniques...

Ultralow-temperature fluids (such as liquid nitrogen, CO2) are novel waterless fracturing technologies designed for dry, water-sensitive reservoirs. Due to their ultralow temperatures, high compression ratios, strong frost heaving forces, and low viscosities, they offer a solution enhancing the permeability of low-permeability In this study, we focus on combined effects high-pressure fluid rock breaking, low-temperature freeze-thaw fracturing, liquid-gas phase transformation expansion...

Injecting ultra-low-temperature fluids, such as liquid carbon dioxide (CO2) and nitrogen (LN2), into deep, low-permeability reservoirs for fracturing is an emerging waterless technology. When these fluids enter the reservoir, they rapidly exchange heat with fracture walls, triggering intense cold shock, which influences development. Although many scholars have studied effects of freezing thawing on coal seams, initial thermal shock process when LN2 first enters rock mass remains unclear....

On the basis of complexity pore structure characteristics a coal reservoir, samples with different ranks were selected to study difference in structures and permeability using nuclear magnetic resonance (NMR), scanning electron microscopy (SEM), mercury intrusion porosimetry (MIP), measurement. Porosity size distribution (PSD) above 20 nm can be analyzed by improved NMR equation, results basically consistent that SEM MIP. The spectra from same location close, but between locations was quite...