| 摘要 |
PROBLEM TO BE SOLVED: To provide a well device which singly has both a function of injecting liquid or gaseous carbon dioxide into an underground coal layer and a function of recovering gaseous methane embedded in the coal layer, and to provide a method of setting the well device. SOLUTION: The well device having the fluid injecting and recovering functions carries out injection of carbon dioxide (CO<SB>2</SB>) into the coal layer 31 in which gaseous methane (CH<SB>4</SB>) is embedded, then substitutes the carbon dioxide for the methane, and recovers the methane in the coal layer. The well device is formed of a main well 20 excavated from the ground surface 30 to the coal layer, a branch well 25 branched from some midpoint of the main well 20 and excavated in the coal layer 31 along a direction of the coal layer, injection port members 21, 23 arranged in the main well 20, for injecting carbon dioxide supplied from the ground side, into the coal layer 31, and recovery port members 15, 26 arranged in the main well and the branch well 25, for recovering methane to the ground side. COPYRIGHT: (C)2006,JPO&NCIPI
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