Research On Different Genetic Anthracite Desorption Character

At present,coalbed methane is very important in China's energy structure. In the past three decades,coalbed methane exploration and development of results show that China's coalbed methane resources are very rich,high,medium and low metamorphic grade of the coal reservoir contain a large number of coalbed methane resources. However, the current domestic commercial development only have made a breakthrough in the Qinshui Basin. Therefore, from reality, it's the most urgent task to be CBM industry researchers that searching a reasonable technical method for CBM exploration and development in other regions. One of the researching differences anthracite became one of the main topics.In the thesis, we respectively collected coal samples from the south Qinshui 3 #, Rujigou 2 #,Lengshuijiang 3 #,causes of three different formation anthracite coal reservoir, and did experiments ,Analysis of aspects from the chemical composition of samples from the coal, causes the pore type, pore size distribution , specific surface area, pore volume and pore distribution characteristics, adsorption characteristics of coal bed methane and desorption analysis of the performance, Using thermodynamics method to calculate the adsorption, desorption process adsorption heat and compared the result,mathematical methods used to fit the experimental results,and obtained differences in understanding of the reservoir,on the analysis of the differences the anthracite of plutonic metamorphism of Ceshui Formation and the anthracite of hydrothermal metamorphism of Yan'an Formation.From the point of view that composition of coal samples, the three coal samples belong to the high rank anthracite, all have good ability to generat methane,in these, Qinshui South 3 # coal is the best; from the coal sample to pore characteristics and surface features analysis, Qinshui South 3 # and Lengshuijiang 3 # coal sample are the majority of the open hole, while the surface area of Qinshui south 3 # coal reservoir is bigger and it's benefit of storing for CBM. Rujigou 2 # coal contains more closed pores, specific surface area and pore volume is small, so it is not conducive to store the coalbed methane;the isothermal desorption experiments show that changes of the adsorption heat great impact than the pressure higher pressure In the high pressure stage; By calculating the heat of adsorption,we can concluded thatthe heat of adsorption in desorption process is greater than the adsorption process,this is the other evidence in the desorption lag.