孔隙結構與孔隙率是影響滲透率之關鍵因子，而孔隙幾何因子乃量化孔隙結構之常用參數。岩石受深埋作用影響，孔隙結構可能因應力條件而改變，然而前人利用孔隙率/滲透率量測結果評估孔隙幾何因子之方法，多僅適用於常壓條件。另外，量測孔隙率/滲透率時，未能採用相同試體，因此，樣本變異性可能影響試驗結果。本研究改良YOKO2高圍壓孔隙率/滲透率量測儀，以脈衝衰減法取代原先YOKO2滲透率量測採用之穩態法，並撰寫脈衝衰減法之解析解與半解析解程式以分析實驗數據率定滲透率。使YOKO2能同步量測承受圍壓條件下之孔隙率/滲透率(YOKO2-T1)。同時，本研究嘗試建立一於承受圍壓條件下孔隙幾何因子量測之新方法，利用孔隙率、滲透率以及氣體滲透率作克林堡修正時所得之滑流因子估算孔隙幾何因子，相較於前人研究更加省時且簡便。配合YOKO2-T1將能使孔隙率、滲透率量測與孔隙幾何因子計算不受試體變異性之影響並縮短實驗程序。本研究以湖山水庫卓蘭層黏土質粉岩與粉土質砂岩作為試體，粉土質砂岩之孔隙率/滲透率測量之圍壓條件為5 MPa~80 MPa，而黏土質粉岩之孔隙率/滲透率測量之圍壓條件為3 MPa~60 MPa。結果顯示；粉土質砂岩孔隙率隨有效應力增加由19.5%降至15.5%，黏土質粉岩孔隙率隨有效應力增加由10.5%降至7.4%。粉土質砂岩滲透率隨有效應力增加由5.69*10-15降至1.73*10-15 m2，黏土質粉岩滲透率隨有效應力增加由3.87*10-16降至5.23*10-17 m2。粉土質砂岩滑流因子隨有效應力增加由0.07增加至0.1 MPa，粉土質砂岩滑流因子隨有效應力增加由0.2增加至0.4 MPa。粉土質砂岩孔隙幾何因子之數值在40~60之間，黏土質粉岩孔隙幾何因子之數值則在5~10之間。以上量測結果皆符合前人研究之成果。說明本研究建立之YOKO2-T1其實驗數據與孔隙幾何因子量測新方法皆具有可信度。;To understand the variation of continue profile of the permeability in stratum, pore geometrical factor used to quantify the pore structure and porosity are key parameters. Pore structure could be changed by stress because of the rocks burial history. However, pore geometrical factor was usually measured under atmosheric pressure by previous studies. And using different rock sample to determine the permeability and porosity, resulting in variability of the samples. This study improve the permeability/porosity measurement system under high confining stress (YOKO2). Using the pulse-decay technology replace the steady-state flow method used by YOKO2 originally. Made YOKO2 can measure the porosity/permeability using the same rock sample. Additionally, this study try to propose a new method to measure the rock pore geometrical factor under confining stress. It could be faster than previous studies. Preliminary results show measurement of the permeability using pulse-decay method is similar to using steady-state flow method. And the values of the pore geometrical factor of the Argillaceous rocks are 5 to 10 which is similar to previous study. It show the method to measure the pore geometrical factor proposed by this study is credible.
