Method for removing methane from coal
AssigneeContinental Oil Company
InventorsRichard L. Every, Luino Dell'Osso, Jr.
Life of this patent
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Abstract
A process for removing methane from a subterranean coal deposit. A carbon dioxide-containing fluid is introduced into the coal deposit through an injection well and held therein for a period sufficient to enable a substantial amount of methane to be desorbed from the surfaces of the coal deposit. Following the hold period, the injected carbon dioxide-containing fluid and desorbed methane are recovered through a recovery well or wells spaced from the injection well. The process is repeated until sufficient methane has been removed to enable safe mining of the coal deposit.
Claims5
A process for removing methane from a subterranean coal deposit comprising:
- a. providing at least one injection well and at least one recovery well spaced therefrom, said wells extending from the surface to said coal deposit;
- b. pressurizing said coal deposit by injecting a gaseous fluid containing at least about 20 percent by weight carbon dioxide through said injection well at a pressure not exceeding the cracking pressure of said deposit into said coal deposit while maintaining said recovery well closed;
- c. stopping said injection and maintaining said deposit in a pressurized condition for a period of time sufficient to enable a substantial amount of methane which is adsorbed on said coal deposit to be desorbed therefrom;
- d. opening said recovery well after step (c) to recover injected fluid and desorbed methane from said coal deposit;
- e. closing said recovery well after step (d);
- and
- f. repeating steps (b) through (e) until enough methane has been removed from said coal deposit to enable the deposit to be worked safely.
Dependencies are inferred from the claim text.