Accelerated Coalbed Methane Dewatering Using CO2 Injection

Abstract

A method for producing methane from a coalbed formation including the accelerated dewatering of the coalbed formation including determining the location of water influx into the coal formation and determining an area to form a permeability barrier in the coal formation to reduce the water influx into the coal formation. A strongly adsorbing fluid is injected through one or more injection wells into the area to form a permeability barrier to the influx of the water. One or more methane production wells are drilled into the coal formation and methane is produced from the coal formation.

What is claimed is: 
     
         1 . A method for producing methane from a coalbed formation, the method comprising:
 determining the location of water influx into the coal formation;   determining an area to form a permeability barrier in the coal formation to reduce the water influx into the coal formation;   injecting a strongly adsorbing fluid through one or more injection wells into the area to form a permeability barrier;   drilling one or more methane production wells into the coal formation; and   producing methane from the coal formation.   
     
     
         2 . The method of  claim 1 , wherein the strongly adsorbing fluid comprises carbon dioxide. 
     
     
         3 . The method of  claim 1 , wherein the strongly adsorbing fluid is selected from the group consisting of carbon dioxide, nitric acid, sulfur hexafluoride, hydrogen sulfide, sulfur dioxide, nitrogen dioxide, sulfur trioxide, trichlorofluoromethane, dichlorofluoromethane, chlorotrifluoromethane, tetrafluoromethane, dichloromonofluoromethane, fluoroform, 1,1,2-trichloro-1,2,2-trifluoromethane, dichlorotetrafluoroethane, hexafluoroethane, chloropentafluoroethane, Lewis base donor molecules with high basicity, primary, secondary, or tertiary amines, alkylamines, aromatic amines, molecules with several amine functions, lactams, amines, urea and its derivatives, pyridine, ammonia, methylamine, buytlamine, tetramethyl ethylenediamine, 1,4-dimethylpiperazine, ethylmethylamine, N-methylpyrollidone, N-methylpyridone, N,N-dimethylformamide and combinations thereof. 
     
     
         4 . The method of  claim 1 , wherein injecting a strongly adsorbing fluid through one or more injection wells into the area to form a permeability barrier comprises fracturing the coalbed formation with the strongly adsorbing fluid. 
     
     
         5 . The method of  claim 1 , wherein the one or more injection wells are horizontal or deviated. 
     
     
         6 . The method of  claim 1 , wherein the one or more injection wells further comprise increasing the surface area contact between the wellbore and the coalbed formation. 
     
     
         7 . The method of  claim 1 , wherein the coal formation comprises one or more cleats and wherein the strongly adsorbing fluid reduces the cleat apertures. 
     
     
         8 . The method of  claim 1 , further comprising treating the well with periodic or non-periodic injection pulses of the strongly adsorbing fluid. 
     
     
         9 . The method of  claim 1 , further comprising injecting the strongly adsorbing fluid at temperatures other than ambient temperatures. 
     
     
         10 . The method of  claim 1 , wherein injecting a strongly adsorbing fluid through one or more injection wells into the area to form a permeability barrier further comprises injecting the strongly adsorbing fluid at a pressure at or above a fracture pressure of the coalbed formation. 
     
     
         11 . The method of  claim 1 , wherein injecting a strongly adsorbing fluid through one or more injection wells into the area to form a permeability barrier further comprises injecting the strongly adsorbing fluid at a pressure below a fracture pressure of the coalbed formation. 
     
     
         12 . The method of  claim 1 , wherein the strongly adsorbing fluid causes the coal formation to swell. 
     
     
         13 . The method of  claim 11 , wherein the swelling of the coal formation by the strongly adsorbing fluid decreases over time. 
     
     
         14 . The method of  claim 1 , further comprising injecting a solid proppant into the one or more injection wells into the area.