不同煤阶煤的微生物增透效果和机理分析

为研究不同煤阶煤的微生物增透效果及其机理,采集不同煤样进行生物甲烷模拟实验,并分别采用光学显微镜、压汞仪、FTIR和XRD进行测试,对比分析煤在生物甲烷代谢前后的表面孔裂隙、孔隙结构、官能团和微晶结构的变化特征。实验结果表明:生物甲烷代谢后煤光片的表面裂隙数量、长度和宽度增加;煤样孔容显著增加,孔隙连通性增强,孔隙结构得以改善,而孔比表面积降低;煤的含氧官能团增多,芳香环部分被打开,并在断裂处引入羟基,其含量也相应增加;芳香核层间距d002增加,芳香层数Nc、堆砌度Lc和延展度La相应减小。微生物不仅能利用煤作为碳源代谢产生甲烷以增加煤层气资源量,还可以改善煤的孔隙结构,有利于提高储层渗透性,同时降低了煤的比表面积,从而有利于煤层气解吸。

Analysis of mechanism and permeability enhancing effect via microbial treatment on different-rank coals

In order to study the effect of permeability increase via microbial treatment on different-rank coals and its mechanism，different coal samples were collected for the bio-methane simulation experiment，in which instruments like optical microscope and mercury-injection apparatus and techniques including FTIR and XRD were utilized to test and analyze the varying characteristics respectively on the surface pores and fractures，pore structures，functional groups and microcrystalline structures of coal samples before and after bio-methane metabolism.The experimental results show that the number，length and width of surface pores and fractures of polished section of coal all saw an increase after biomethane metabolism.The pore volume of coal samples increase significantly，the connectivity is enhanced and pore structure is improved，whereas the specific surface area of pore decreases.While the oxygen-containing functional groups of coal increase，the aromatic rings are opened gradually.Also the hydroxyl is introduced to the split parts and its content increases.With the aromatic carbon layer distance(d002)increases，the number of aromatic layer(Nc)，packing degree(Lc)and elongation(La)decrease accordingly.Bio-methane metabolism not only can use coal as a carbon source to produce methane further to increase coalbed methane resources but also can improve the pore structure of coal，increase the reservoir permeability and reduce the specific surface area of coal for the coalbed methane desorption，which is of great engineering significance for coalbed methane development.