Method for treating a mixture of gaseous fluids within a solid carbonaceous subterranean formation

A method for recovering methane from a solid carbonaceous subterranean formation penetrated by an injection well and a production well, the method comprising the steps of:

• a) injecting a desorbing fluid comprising methane and carbon dioxide into the solid carbonaceous subterranean formation through the injection well, the desorbing fluid having a volume percentage of carbon dioxide equal to A;
• b) recovering an effluent comprising methane from the formation through the production well;
• c) monitoring the composition of the effluent produced in step b);
• and
• d) ceasing recovery of the effluent produced in step b) when a volume percentage of carbon dioxide in the effluent recovered in step b) is greater than 0.5 A.

A method for recovering methane from a solid carbonaceous subterranean formation penetrated by an injection well and a production well, the method comprising the steps of:

• a) injecting a desorbing fluid, having a volume ratio of carbon dioxide to other injected desorbing fluid components equal to B, into the solid carbonaceous subterranean formation through the injection well;
• b) recovering an effluent comprising injected desorbing fluid and methane from the production well;
• c) monitoring the volume ratio of the carbon dioxide to other injected desorbing fluid components contained in the effluent recovered at the production well;
• and
• d) ceasing recovery of the effluent from the production well when the volume ratio of carbon dioxide to other injected desorbing fluid components within the effluent recovered at the production well is greater than 0.5 B and at least 70 percent of the methane available to the production well has been recovered.

A method for disposing carbon dioxide within a solid carbonaceous subterranean formation, the method comprising the steps of:

• a) injecting a desorbing fluid, having a volume ratio of carbon dioxide to other injected desorbing fluid components equal to B, into the solid carbonaceous subterranean formation;
• b) withdrawing a gaseous effluent having a volume ratio of carbon dioxide to other desorbing fluids of less than B from the formation;
• and
• c) ceasing to withdraw the gaseous effluent from the formation when a volume ratio of carbon dioxide to other injected desorbing fluid components within the gaseous effluent withdrawn in step b) is greater than 0.5 B.

A method for recovering methane from a coal seam penetrated by an injection well and a production well, the method comprising the steps of:

• a) injecting a desorbing fluid, having a volume ratio of carbon dioxide to other injected desorbing fluid components equal to B, into the coal seam through the injection well;
• b) withdrawing a gaseous effluent comprising methane and carbon dioxide and having a volume ratio of carbon dioxide to other injected desorbing fluid components of less than B from the coal seam through the production well;
• and
• c) ceasing to withdraw the gaseous effluent from the coal seam when a volume ratio of carbon dioxide to other injected desorbing fluid components within the gaseous effluent withdrawn in step b) is greater than 0.5 B.