| 摘要 |
The invention describes a process for the recovery of methane contained in a coal seam, wherein a fluid is injected into coal seam via the two injection wells 1 and 2. Both injection wells 1 and 2 are located at approximately the same distance from the production well 3. The driving gas flow G1 is injected into the coal seam from the injection well 1 in a pulsed manner. The driving gas flow G2 is also introduced into the coal seam from the injection well 2 in a pulsed manner. Pulse durations of approx. 20 min are used thereby. The time lag between two pulses of an injection is approx. 1 hour. The injected gas quantities G1 and G2 are thereby in the same magnitude in each case. Due to the overlap of the positioned and pulsed driving gas flows G1 and G2, a resulting gas flow G3 forms, which moves in the direction of the production well 3. The methane is thus driven in the direction of the production well 3 by means of the positioned and pulsed driving gas flows. In this embodiment of the invention, nitrogen and carbon dioxide are injected so as to alternate, so that the different characteristics of both gases can be used for the coal bed methane recovery.
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