Tailings reservoirs generally consist of a tailings dam, a tailings conveying system and a drainage system, which are indispensable facilities and provide security and environmental protection for storing tailings and clarifying water in some industries (e.g., metallurgy, non-ferrous building materials, nuclear and chemical industries). Consequently, consolidating seepage prevention and treatment is important. When applied to seepage prevention works for tailings reservoirs, current seepage prevention technologies can cause destruction of the dam and require further construction sites. It is therefore essential to adopt new types of advanced and practical technologies. Aimed at studying the feasibility of the application of non-water reaction polymer grouting technology in seepage prevention of tailings reservoirs and acquiring the properties for practical engineering, an analysis of the environmental impact, chemical resistance and permeability of the polymer material, and the main technical characteristics of the polymer cutoff wall was conducted. The test results showed that the polymer grouting technology applied to seepage prevention works of a tailings reservoir caused little disturbance to the dam, possessed good anti-seepage performance and perfect durability. This study may provide a reference for the seepage control of tailings reservoirs.

Low-field nuclear magnetic resonance has become one of the main methods to characterize static parameters and dynamic changes in unconventional reservoirs. The research focus of this paper is process simulation of coalbed methane (CBM) production. The dynamic variation of pore volume with different pore sizes during pressure drop, methane desorption-diffusion process, and methane-water interaction during migration is discussed. Moreover, the calculation principles of NMR single and multifractal models are systematically described, and the applicability of NMR fractal models within different research contexts is discussed. Four aspects need urgent attention in the application of this technology in CBM production: (1) overburden NMR technology has limitations in characterizing the stress sensitivity of shale and high-rank coal reservoirs with micropores developed, and we should aim to enable an accurate description of micropore pore stress sensitivity; (2) dynamic NMR physical simulation of reservoir gas and water production based on in-situ and actual geological development conditions should become one of the key aspects of follow-up research; (3) low-temperature freeze-thaw NMR technology, as a new pore-fracture characterization method, needs to be further applied in characterizing the distribution characteristics of pores and fractures; and (4) NMR fractal model should be used as the main theoretical method to expand the simulation results. The applicability of different fractal models in characterizing pore-fracture structure (static) and CBM production process (dynamic) needs to be clarified.