摘要: | 地下深處的煤層通常含有甲烷(CBM),其甲烷會被吸附在煤層中的孔隙裡與分子間,由前人以煤進行的氣體吸附實驗已証明,煤對於二氧化碳的吸附力比對甲烷來的高,所以在地下的煤層注入二氧化碳之後,二氧化碳會取代甲烷被煤層吸附,而儲存在地下,除非煤層中的壓力減小或是溫度上升,二氧化碳才有可能回到地表。而氦氣由於本身是惰性氣體,和煤不容易起反應,且對於煤本身的膨脹和收縮並無太大的影響,所以是最適合用來測定孔隙率與滲透率的氣體。為探討煤層滲透率與樣本異向性之關聯,除必先測定煤素質成份與鏡煤素反射率等煤質特性外,本研究擬採用已取得之澳洲煤礦樣本,以He 與CO2 分別在 5、10、20、30、40MPa 下檢測樣本平行與垂直層面方向之滲透率,並以電子顯微鏡觀察樣本受壓前後之孔隙與裂隙連通狀況。目的為探討煤層異向性與滲透率之關聯,以供未來評估溫室氣體地下封存與增加煤層甲烷回收可行性之依據。 In order to increase the recovery ratio of coal bed methane (CBM), CO2 sequestration is considered in deep coal mines. From previous literatures, the adsorption of CO2 had been proved to be much stronger than that of CH4. However, the study of coal permeability and anisotropy is needed in CCS assessment. Australian coal samples are selected for this study. Experiment work will start from characterization of coal, such as maceral/chemical composition and vitrinite reflectance measurements. By using He and CO2 gases, sample permeability will be detected under pressures of 5, 10, 20, 30, 40 MPa, along parallel and perpendicular to bedding plane directions, respectively. Furthermore, the connectivity of pores and fractures of raw and pressurized samples will be examined under SEM. The purpose of this study is to evaluate the relationship among coal characteristics, permeability and anisotropy. The results of this study will be beneficial in considering future feasibility of GHG sequestration as well as increasing recovery ratio of CBM in coal seams. 研究期間:9908 ~ 10007 |