System and method for enhancing coal bed methane recovery

Abstract

A system includes first and second wells. The first well has a first tube that extends from a first well head to a first end disposed within a coal seam. The second well is disposed at a distance from the first well and includes a second tube that extends from a second well head to a second end disposed within the coal seam. A pump is coupled to the first well and is configured to supply the first tube with pressurized fluid that includes nutrients for methanogenesis. At least a portion of the pressurized fluid introduced into the first tube of the first well is received within the second tube of the second well by way of the coal seam.

What is claimed is: 
     
         1 . A system, comprising:
 a first well including a first tube that extends from a first well head to a first end disposed within a coal seam;   a second well disposed at a distance from the first well, the second well including a second tube that extends from a second well head to a second end disposed within the coal seam; and   a pump coupled to the first well and configured to supply the first tube with pressurized fluid that includes nutrients for methanogenesis,   wherein at least a portion of the pressurized fluid introduced into the first tube of the first well is received within the second tube of the second well by way of the coal seam.   
     
     
         2 . The system of  claim 1 , wherein the first well includes a nozzle disposed at the first end configured with a plurality of aperture for directing the pressurized fluid into the coal seam. 
     
     
         3 . The system of  claim 1 , further comprising:
 a third well disposed at a distance from the first and second wells, the third well including a third tube that extends from a third well head to a third end disposed within the coal seam,   wherein at least a portion of the pressurized fluid introduced into the first tube of the first well is received within the second tube of the second well by way of the coal seam.   
     
     
         4 . The system of  claim 1 , further comprising:
 a third well disposed at a distance from the first and second wells, the third well including a third tube that extends from a third well head to a third end disposed within the coal seam; and   a second pump coupled to the third well and configured to supply the third tube with pressurized fluid that includes nutrients for methanogenesis,   wherein at least a portion of the pressurized fluid introduced into the first and second tubes of the first and second wells is received within the second tube of the second well by way of the coal seam.   
     
     
         5 . The system of  claim 1 , wherein the fluid is provided to the pump from a tank. 
     
     
         6 . The system of  claim 1 , wherein the first tube is connected to the second tube by a conduit that extends between the first well head and the second well head. 
     
     
         7 . The system of  claim 6 , wherein the pump is disposed along the length of the conduit. 
     
     
         8 . The system of  claim 7 , wherein a nutrient injection system is disposed along the length of the conduit. 
     
     
         9 . A method, comprising:
 injecting a fluid having a first nutrient concentration into a coal seam through a first well under a first pressure; and   extracting a second fluid having a second nutrient concentration from the coal seam through a second well disposed apart from the first well,   wherein the second nutrient concentration is less than a first nutrient concentration.   
     
     
         10 . The method of  claim 9 , further comprising:
 drilling a test well into the coal seam;   assessing at least one characteristic of the coal seam using the test well;   drilling the first well; and   drilling the second well at a distance from the first well based on the at least one characteristic.   
     
     
         11 . The method of  claim 10 , further comprising:
 injecting a tracer into the first well; and   extracting at least a portion of the tracer from the second well.   
     
     
         12 . The method of  claim 11 , further comprising obtaining a measurement of permeability of the coal seam based on a rate at which the tracer is injected to the first well and the portion of the tracer is extracted from the second well. 
     
     
         13 . The method of  claim 9 , further comprising extracting a third fluid having a third nutrient concentration from the coal seam through a third well disposed apart from the first and second well. 
     
     
         14 . The method of  claim 13 , wherein the second and third nutrient concentrations are less than the first nutrient concentration. 
     
     
         15 . The method of  claim 9 , further comprising:
 increasing the second nutrient concentration of the second fluid to provide the first fluid having the first concentration at a nutrient injection system coupled to the second well; and   supplying the first fluid to the first well by way of a conduit between the nutrient injection system and the first well.   
     
     
         16 . The method of  claim 9 , further comprising:
 injecting a third fluid having a third nutrient concentration into the first well after the first fluid has been injected into the first well,   wherein the third nutrient concentration is less than the first and second nutrient concentrations.   
     
     
         17 . The method of  claim 16 , wherein the third fluid forces the first fluid into spaces of the coal seam and combined with the first fluid to create the second fluid having the second concentration. 
     
     
         18 . The method of  claim 9 , wherein the nutrients are for producing methanogenesis. 
     
     
         19 . The method of  claim 9 , wherein the first pressure is up to and including approximately 100 pounds per square inch.