Process to increase the area of microbial stimulation in methane gas recovery in a multi seam coal bed/methane dewatering and depressurizing production system through the use of horizontal or multilateral wells

Abstract

A process to increase the area of microbial stimulation in a process of methane gas recovery in a multi seamed coal bed/methane dewatering and depressurizing production system by first utilizing an underbalanced multilateral drilling technique. At this point in the process one could introduce the microorganisms into the horizontal well bore to achieve a greater area of stimulation of the coal bed than would a vertical well. An even more preferred method would to first drill a series of lateral wells off of the horizontally drilled well bore, so as to increase or maximize the area of coal bed which is being covered. At that point, one would take the steps of what is known in the art of introducing a particular type of microorganism, such as the type disclosed in the '535 patent, which would then be injected via the plurality of lateral bores into the coal bed formation, to maximize the area of penetration, which would include, most, if not all, of the area of the coal bed through the series of lateral wells. After the microbes have been injected into the formation through the lateral wells, one would then undertake these further steps of completing the production steps involved in recovering any methane gas produced according to the process disclosed and claimed herein. The methane gas produced would flow into the series of lateral boreholes through the annulus between the drill string and the carrier string, and the principal borehole would bring it to surface, where the water would be separated from the methane gas to be collected.

1 . A process to maximize the area of microbial stimulation of a coal bed to recover methane gas from a formation through a single well system, comprising the following steps:
 a. drilling a first substantially vertical bore hole to the depth of the coal bed;   b. drilling a horizontal well from the vertical bore hole at substantially the depth of the coal bed and extending the well a distance to cover substantially the length of the coal bed so that the well can serve as an injection well;   c. injecting microbes into the coal bed through the injection well so that substantially a maximum area of the coal bed is stimulated by the microbes within the bed to maximize the production of methane throughout substantially the entire area of the coal bed into which the injection well was drilled; and   d. allowing the methane gas produced to flow up the well system so that the well serves as a collection well where methane gas can be collected from the collection well and moved up the vertical bore hole to be collected and stored at the surface.   
   
   
       2 . The process in  claim 1 , wherein the horizontal well being in pressure communication with other horizontal and/or lateral wells to maintain subsurface environments of chemistry, temperature, salinity and pressure so the environment conditions in the formation can be maintained for the maximum beneficial microorganism conditions. 
   
   
       3 . The process in  claim 1 , wherein the production process is undertaken in an underbalanced condition. 
   
   
       4 . The process in  claim 1 , wherein the process utilizes microbes well known in the art. 
   
   
       5 . The process in  claim 1 , wherein area of coal bed which is stimulated by the microbes is substantially higher than the area stimulated by a vertical bore hole. 
   
   
       6 . A process to increase the area of a seam of coal into which microbes can be introduced to stimulate the recovery of methane gas from the seam of coal, comprising the following steps:
 a. drilling a first substantially vertical bore hole;   b. drilling a horizontal bore hole from the vertical bore hole at substantially the depth of the seam of coal;   c. extending the horizontal bore hole a distance to cover substantially the length of the seam of coal;   d. providing an injector string system within the bore hole to introduce microbes into the seam of coal to stimulate the coal within the seam to produce methane throughout substantially the length of the horizontal bore hole;   e. the horizontal well being in pressure communication with other horizontal and/or lateral wells to maintain subsurface environments of chemistry, temperature, salinity and pressure so the environment conditions in the formation can be maintained for the maximum beneficial microorganism conditions; and   f. retrieving the methane gas from the horizontal bore hole and moving the gas up the vertical bore hole to be collected and stored at the surface.   
   
   
       7 . The process in  claim 6 , wherein the entire process of drilling the vertical, horizontal and lateral bore holes is done in an underbalanced condition. 
   
   
       8 . The process in  claim 6 , wherein the lateral bore holes are drilled substantially at the same depth as the horizontal bore hole within the coal bed. 
   
   
       9 . The process in  claim 6 , wherein the microbes introduced into the coal bed are of the type known in the art. 
   
   
       10 . The process in  claim 6 , wherein the quantity of coal bed stimulated is substantially maximized through the use of the plurality of lateral bore holes. 
   
   
       11 . A process to increase the area of microbial stimulation of a coal bed to recover methane gas, comprising the following steps:
 a. drilling a first substantially vertical bore hole to the depth of the coal bed;   b. drilling a horizontal bore hole from the vertical bore hole at substantially the depth of the coal bed;   c. extending the horizontal bore hole a distance to cover substantially the length of the coal bed;   d. drilling a plurality of lateral well bores from the horizontal bore hole to penetrate a greater area of the coal bed;   e. injecting microbes into the coal bed through the various lateral bore holes to stimulate the coal within the bed to produce methane throughout substantially the entire area of the coal bed into which the lateral wells were drilled;   f. the lateral wells extending from the horizontal well being in pressure communication with other horizontal and/or lateral wells to maintain subsurface environments of chemistry, temperature, salinity and pressure so the environment conditions in the formation can be maintained for the maximum beneficial microorganism conditions; and   g. recovering the methane gas from the various lateral bore holes into the horizontal bore hole and moving the gas up the vertical bore hole to be collected and stored at the surface.   
   
   
       12 . The process in  claim 11 , wherein the entire process of drilling the vertical, horizontal and lateral bore holes is done in an underbalanced condition. 
   
   
       13 . The process in  claim 11 , wherein the lateral wells are drilled substantially at the same depth as the horizontal well within the coal bed. 
   
   
       14 . The process in  claim 11 , wherein the microbes introduced into the coal bed are of the type known in the art. 
   
   
       15 . The process in  claim 11 , wherein the quantity of coal bed stimulated is substantially maximized through the use of the plurality of lateral wells. 
   
   
       16 - 18 . (canceled)