Acoustic testing is a widely used technique to measure the coal mechanical properties under high temperature and pressure in situ conditions.This study compared the acoustic wave characteristics of briquette and raw c...Acoustic testing is a widely used technique to measure the coal mechanical properties under high temperature and pressure in situ conditions.This study compared the acoustic wave characteristics of briquette and raw coal under various temperature and pressure conditions.The results show that the longitudinal wave velocity(Vp)decreases with an increasing vitrinite content.A large number of the vitrinite content enhances the process in which the temperature and pressure changed the Vp.The Vp of briquette decreases approximately linearly with the temperature compared to raw coal.The Vp of raw coal experiences initially a rapid,then gradual,and finally the moderate increasing trend with the increase in confining pressure.However,in briquette,the Vp increases approximately linearly with the confining pressure.The results indicate that the Vp is more sensitive to temperature under low confining pressure and peaks at 50℃−60℃ than high confining pressure.However,the Vp is less sensitive to temperature under higher confining pressure,and the positive effect of high confining pressure is dominant.Understanding the mechanical properties of coal under high pressure and temperature develops better insight into coalbed methane(CBM)exploration from deep reservoirs.展开更多
基金This research was financially supported by the National Natural Science Foundation of China(Grant Nos.42072191 and 42130802)the Shanxi Science and Technology Plan Announced Bidding Project(No.20201101003)+2 种基金the China Huaneng Group Scicence and Technology Project(No.HNKJ20-H87)the Qing Lan Project of Jiangsu ProvincePriority Academic Program Development of Jiangsu Higher Education Institutions(PPAD).
文摘Acoustic testing is a widely used technique to measure the coal mechanical properties under high temperature and pressure in situ conditions.This study compared the acoustic wave characteristics of briquette and raw coal under various temperature and pressure conditions.The results show that the longitudinal wave velocity(Vp)decreases with an increasing vitrinite content.A large number of the vitrinite content enhances the process in which the temperature and pressure changed the Vp.The Vp of briquette decreases approximately linearly with the temperature compared to raw coal.The Vp of raw coal experiences initially a rapid,then gradual,and finally the moderate increasing trend with the increase in confining pressure.However,in briquette,the Vp increases approximately linearly with the confining pressure.The results indicate that the Vp is more sensitive to temperature under low confining pressure and peaks at 50℃−60℃ than high confining pressure.However,the Vp is less sensitive to temperature under higher confining pressure,and the positive effect of high confining pressure is dominant.Understanding the mechanical properties of coal under high pressure and temperature develops better insight into coalbed methane(CBM)exploration from deep reservoirs.
