Evaluation method of permeability performance and similarity of raw coal based on NMR coal model materials

MA Yankun; YAN Zewen

doi:10.12438/cst.2024-1567

Abstract：Physical model experiments are an important research method to reveal the mechanism of coal rock dynamic disasters,and the preparation of coal like physical model materials is the key to laying similar coal seams.For dynamic disasters such as coal and gas out-bursts,water inrush,etc.caused by fluid solid coupling and temperature loss,simulating the permeability performance of materials is the key to the experiment.To reasonably evaluate the similarity between simulated material permeability and raw coal,a method of using Pearson correlation coefficient between material pore structure and permeability during loading and unloading process for similarity evalu-ation was proposed,and coal like materials were configured for experimental verification.The results showed that:Correlation coefficient P can effectively reflect the similarity of the permeability performance between raw coal and coal like materials during the loading and un-loading process.The minimum correlation coefficients P for the porosity,permeability,and compressibility coefficient(CP)of the two coal samples were 0.624,0.913,and 0.888,respectively.The permeability performance remained strongly similar or extremely similar in over-all changes.During the loading and unloading process,the porosity and permeability of both coal samples are negatively correlated with confining pressure,and the permeability is highly sensitive to stress.CP of the two coal samples is negatively correlated with confining pressure,and CP value during unloading is higher than that during loading.The research results provide a basis for evaluating the similar-ity of permeability performance of coal like physical model materials,and have guiding significance for conducting physical model experi-mental research.