全球能源需求日益增加，對於新替代能源的開發利用逐漸重視，其中以煤層氣 (Coal Bed Methane)為近幾年熱門的研究之一。本研究選用來自澳洲鮑溫及雪梨盆地二疊紀之煤樣，欲評估煤層氣在地層中的含量，頇先了解煤的物化特性。針對煤的物性作Langmuir表面積、孔隙體積、工業分析、孔隙率與滲透率等量測，而化性則進行鏡煤素反射率、煤素質組成分析、熱裂分析與元素分析等詴驗。研究目的為瞭解煤之氣體吸附特性，並利用其物化特性與氣體吸附量的差異作比對用以探討與氣體封存之關聯性。實驗結果顯示樣本鏡煤素反射率介於0.54~1.03%，裂解溫度 (Tmax)則為433~439℃，揮發份含量約在23.81~28.95%，屬於未成熟至成熟之高揮發份煙煤，利用Langmuir 等溫吸附線表示澳洲六個煤樣之氣體吸附量，其中最大為鮑溫盆地之B2、最低為雪梨盆地之S1與S2，主要影響等溫吸附線的因子為煤樣表面積與孔隙體積，孔隙體積越多相對表面積也就越大，其氣體吸附量也就越多。伴隨煤的演化會使次生孔隙與孔隙體積增加且割理和裂隙發育更發達，相較煤素質組成則對孔隙體積影響不大。由於裂隙為煤層的流體快速傳輸路徑，B3煤樣有較高滲透率與孔隙率是因發達且連續性裂隙所致，故相對其餘滲透率偏低的澳洲煤樣來說，B3具較佳氣體封存經濟效益。Global energy demand for the development and utilization of new alternative energy is increasing for a long time, in which CBM (Coal Bed Methane) is one of the popular research topics in recent years. The purpose of this study is to perform a series of physical and chemical characteristic studies of coal, so as to understand the relation between coal properties and gas adsorption storage. Permian coals from Bowen and Sydney Basin, Australia, were examined in this study. The results showed that vitrinite reflectance is ranged 0.54~1.03%, composed mostly of vitrinite, and classified as immatured to matured high volatile bituminous coal. Langmuir adsorption isotherm indicates B2 from Bowen Basin possesses the highest adsorption capacity, where as S1 and S2 from Sydney Basin exhibit the lowest adsorption capacity. The difference in adsorption isotherm is mainly controlled by surface area and volume of pores. Both secondary porosity and pore volume increased with cleats and fractures developed after coalification. The influence of maceral composition is relatively less important. Most of the permeability of coal is low in samples studied, except B3 coal exhibits the highest permeability and porosity, which can be attributed to well developed and connected fractures. B3 is believed to be the most promising target for gas sequestration.
