Accurate porosity measurement of coal cuttings is critical for coalbed methane reservoir evaluation but remains challenging due to sample fragility, dual-porosity structures, and limitations of traditional destructive methods such as mercury intrusion porosimetry and gas adsorption. This study presents a novel method based on low-field nuclear magnetic resonance (LF-NMR) technology combined with copper sulfate (CuSO₄) solution to eliminate surface water signal interference. By establishing a linear calibration between NMR signal amplitude and water volume, and utilizing the rapid relaxation特性 of CuSO₄ to shield free water, the method enables accurate separation of pore water signals from skeletal volume signals in coal cuttings. Experimental results demonstrate that this approach achieves a relative porosity measurement error of less than 1.5% without sample destruction. Optimal testing is recommended using coal cuttings with particle sizes ranging from 1.7 to 2.36 mm. This non-destructive, rapid LF-NMR-based method provides reliable technical support for coal reservoir physical property

Natural gas hydrates are widely distributed in seabed sediments and permafrost regions around the world. In addition to their abundant global reserves, the clean combustion characteristics and high energy density of natural gas hydrates make them one of the most promising alternative energy resources for the future. As a result, the growing demand for commercializing natural gas hydrates has drawn significant attention from scientists and engineers across the globe.

The low-field NMR offline saturated fluid method is used to analyze oil-rich coal, supporting the study of its pyrolysis characteristics and the evolution of its pore structure.

With the development of Enhanced Oil Recovery (EOR) technologies, gas flooding, particularly CO₂ miscible flooding, is a highly promising approach to improve recovery in China’s low-permeability reservoirs. This paper presents a study of CO₂ miscible flooding using low-field NMR, beginning with an overview of the mechanisms of CO₂ miscible flooding.

In recent years, natural gas hydrates have attracted increasing attention as a clean and efficient new energy source. China possesses abundant natural gas hydrate resources, with a geological resource volume of 1.53 × 10¹⁴ m³ and a technically recoverable volume of 5.3 × 10¹³ m³.

Natural gas hydrates are crystalline compounds in which methane molecules are trapped within a lattice of water molecules under low-temperature and high-pressure conditions, commonly known as “combustible ice.”

Coal wettability is an important physicochemical parameter for studying coal reservoirs. Beyond its applications in coal chemistry, mining, and safety management, research on coal wettability also plays a significant role in coalbed methane production.

The water blocking effect originates during oil and gas development, occurring when drilling or completion fluids invade the petroleum reservoir, leading to a reduction in hydrocarbon-phase permeability near the wellbore.

Changes in the state and content of water in coal–water slurry are the fundamental cause of its macroscopic rheological behavior. Studying the migration and variation of water states helps to elucidate, from a microscopic perspective, the mechanisms governing changes in slurry rheology, thereby providing a basis for the design and optimization of process parameters in coal pipeline transport systems.

As an advanced scientific instrument, what role does Nuclear Magnetic Resonance (NMR) play in coal mining and coalbed methane management, and how will it develop in the future? Recently, Instrumentation Information Network interviewed Associate Professor Jiaguang Kan from China University of Mining and Technology, as well as Dr. Yong Sun from Professor Cheng Zhai’s team.