Ultrasonic elastic characteristics of five kinds of metamorphic deformed coals under room temperature and pressure conditions  

作　　者：WANG Yun XU XiaoKai YANG DeYi 

机构地区：[1]Institute of Geochemistry, Chinese Academy of Sciences [2]China University of Mining & Technology, College of Geoscience and Surveying Engineering [3]Taiyuan University of Technology

出　　处：《Science China Earth Sciences》2014年第9期2208-2216,共9页中国科学（地球科学英文版）

基　　金：supported by National Natural Science Foundation of China (Grant Nos. 41172145, 41372163 and 41104084);National Basic Research Program of China (Grant No. 2014CB440905);National Special Fund of China (Grant Nos. 2011ZX05: 035-001-006HZ and 035-002-003HZ, 008-006-22, 049-01-02 and 019-003);PetroChina Innovation Foundation (Grant No. 2011D-5006-0303)

摘　　要：The calibration of the elastic characteristics of deformed coals is essential for seismic inversion of such units, because the prediction of coal deformation is essential for both mining safety and methane production. Therefore, many samples of broken and mylonitic deformed coal were tested with ultrasonic waves in the laboratory. These samples came from four mining areas: the Huainan, Pingdingshan, Hebi and Jiaozuo coal mines, which present five different metamorphic ranks shown as cylinders striking across circular limits of steel. Under normal pressures and temperatures, ultrasonic P- and S-wave tests show that the velocities, quality factors, and elastic moduli of the deformed coals were greatly reduced compared with undeformed coals. Also, some correlation was found between the P- and S-wave velocities in the deformed coals. However, there is no evidence of linear correlations between velocity and density, velocity and quality factor, or the quality factors of P- and S-waves. Compared with the elastic characteristics of undeformed coals, such as P- and S-wave velocity ratios or Poisson's ratio, those of deformed coals generally decrease and the P-wave quality factors are less than those of S-waves. Moreover, the analysis of the relationship between pore structure and elastic modulus shows a better correlation between the P- and S-wave velocities and effective porosity, pore volume and specific surface area. Also, there are similar relationships between the pore structure and the Young's and shear moduli. However, there are no such correlations with other moduli. Correlations between these elastic moduli, pore structure, coal rank and density were not found for the various samples of deformed coals, which is consistent with only structural destruction occurring in the deformed coals with other physical properties remaining unchanged. The experimental results show that it is possible to predict the deformation of coals with multi-component seismic elastic inversion.The calibration of the elastic characteristics of deformed coals is essential for seismic inversion of such units, because the pre- diction of coal deformation is essential for both mining safety and methane production. Therefore, many samples of broken and mylonitic deformed coal were tested with ultrasonic waves in the laboratory. These samples came from four mining areas： the Huainan, Pingdingshan, Hebi and Jiaozuo coal mines, which present five different metamorphic ranks shown as cylinders striking across circular limits of steel. Under normal pressures and temperatures, ultrasonic P- and S-wave tests show that the velocities, quality factors, and elastic moduli of the deformed coals were greatly reduced compared with undeformed coals. Also, some correlation was found between the P- and S-wave velocities in the deformed coals. However, there is no evidence of linear correlations between velocity and density, velocity and quality factor, or the quality factors of P- and S-waves. Com- pared with the elastic characteristics of undeformed coals, such as P- and S-wave velocity ratios or Poisson＇s ratio, those of deformed coals generally decrease and the P-wave quality factors are less than those of S-waves. Moreover, the analysis of the relationship between pore structure and elastic modulus shows a better correlation between the P- and S-wave velocities and effective porosity, pore volume and specific surface area. Also, there are similar relationships between the pore structure and the Young＇s and shear moduli. However, there are no such correlations with other moduli. Correlations between these elastic moduli, pore structure, coal rank and density were not found for the various samples of deformed coals, which is consistent with only structural destruction occurring in the deformed coals with other physical properties remaining unchanged. The ex- perimental results show that it is possible to predict the deformation of coals with multi-component seismic elastic inversion.

关 键 词：deformed coal metamorphic rank ultrasonic measurement elastic characteristics 

分 类 号：P618.11[天文地球—矿床学]