Igniting an underground coal seam in an underground coal gasification process, ucg

Abstract

An ignition apparatus ( 150 ) configured to ignite an underground coal seam ( 151 ). The ignition apparatus ( 150 ) comprising an ignition system, a positioning system, a sensor ( 170 ) and a controller ( 165 ). The ignition system comprises ignition means and an ignition tool ( 155 ) for igniting the underground coal seam ( 151 ) from within the well channel ( 154 ) or well liner encasing the well channel ( 154 ). The positioning system comprises coiled tubing ( 156 ) connected to the ignition tool ( 155 ) and extendible through a well head ( 153 ) within the well channel ( 154 ) to position the ignition tool ( 155 ) at a desired location within the well channel ( 154 ). The positioning system further comprises a spool ( 157 ) for transporting and dispensing the coiled tubing ( 156 ).

1 . An ignition apparatus for igniting an underground coal seam from within a well channel that extends through the seam, said apparatus comprising:
 an ignition system comprising ignition means and an ignition tool for igniting the underground coal seam from within the well channel; and   a positioning system comprising coiled tubing connected to the ignition tool and extendible within the well channel to position the ignition tool at a desired location within the well channel.   
     
     
         2 . The ignition apparatus of  claim 1 , wherein the ignition means comprises an electrical spark generator and a power supply for generating the spark. 
     
     
         3 . The ignition apparatus of  claim 1 , wherein the ignition means comprises an electrical heat resistor and a power supply for electrifying the resistor. 
     
     
         4 . The ignition apparatus of  claim 1 , wherein the ignition means comprises at least one type of ignition chemical, such as a pyrophoric substance. 
     
     
         5 . The ignition apparatus of  claim 1 , wherein the ignition means comprises pure oxygen or substantially pure oxygen that ignites the coal seam directly. 
     
     
         6 . The ignition apparatus of any one of the preceding claims, wherein the ignition tool is connected to the coiled tubing in a fluid-tight manner. 
     
     
         7 . The ignition apparatus of  claim 6 , wherein the ignition tool is connected to the coiled tubing by way of a screw thread or weld. 
     
     
         8 . The ignition apparatus of any one of the preceding claims, wherein the ignition tool comprises a tool body having an inlet end connected to the coiled tubing. 
     
     
         9 . The ignition apparatus of any one of the preceding claims, wherein the coiled tubing comprises a single tube connected to the tool body. 
     
     
         10 . The ignition apparatus of any one of  claims 1  to  9 , wherein the coiled tubing comprises an inner tube extending within an outer tube, and one or both of the inner and outer tubes are connected to the tool body. 
     
     
         11 . The ignition apparatus of any one of the preceding claims, wherein the positioning system further comprises a spool from which the coiled tubing is unspooled. 
     
     
         12 . The ignition apparatus of  claim 9 , wherein the ignition means comprises an oxidant source and oxidant is fed to the ignition tool externally of the single tube. 
     
     
         13 . The ignition apparatus of  claim 11  or  claim 12 , wherein the ignition means comprises an ignition fuel source and/or ignition chemical source, and ignition fuel and/or ignition chemical is fed to the ignition tool via the single tube. 
     
     
         14 . The ignition apparatus of  claim 10 , wherein the ignition means comprises an oxidant source and oxidant is fed to the ignition tool via the outer tube. 
     
     
         15 . The ignition apparatus of  claim 10  or  claim 11 , wherein the ignition means comprises an ignition fuel source and/or ignition chemical source, and ignition fuel and/or ignition chemical is fed to the ignition tool via the inner tube. 
     
     
         16 . The ignition apparatus of any one of the preceding claims, wherein the coiled tubing comprises heat-exchange formations. 
     
     
         17 . The ignition apparatus of any one of the preceding claims, wherein the coiled tubing comprises positioners that help position the ignition tool within the well channel. 
     
     
         18 . The ignition apparatus of any one of the preceding claims, wherein the ignition tool comprises at least one inlet that is in fluid communication with at least one tube of the coiled tubing. 
     
     
         19 . The ignition apparatus of  claim 18 , wherein the ignition tool comprises at least one outlet that is in fluid communication with the at least one inlet. 
     
     
         20 . The ignition apparatus of  claim 19 , wherein the ignition tool comprises a detachable cap or plug covering the outlet. 
     
     
         21 . The ignition apparatus of any one of the preceding claims, wherein the ignition tool comprises a mixing chamber within which ignition fuel, oxidant and/or ignition chemical can mix. 
     
     
         22 . The ignition apparatus of  claim 21 , wherein the mixing chamber contains a Venturi device and/or at least one baffle. 
     
     
         23 . The ignition apparatus of  claim 19  or  claim 20 , wherein the ignition tool comprises a gas diffuser adjacent the at least one outlet. 
     
     
         24 . The ignition apparatus of any one of the preceding claims, wherein the ignition tool comprises flow deflectors. 
     
     
         25 . The ignition apparatus of any one of the preceding claims, wherein the ignition tool comprises heat-exchange formations. 
     
     
         26 . The ignition apparatus of any one of the preceding claims, wherein the coiled tubing comprises heat-exchange formations. 
     
     
         27 . The ignition apparatus of any one of the preceding claims further comprising one or more sensors for sensing and reporting conditions in the ignition tool, adjacent the ignition tool, well channel and/or adjacent coal seam. 
     
     
         28 . The ignition apparatus of any one of the preceding claims further comprising a thermocouple for sensing the temperature in the well channel, coal seam or ignition tool. 
     
     
         29 . The ignition apparatus of any one of the preceding claims further comprising a controller operable to trigger ignition, including the provision of electrical energy or ignition fuel, oxidant or the release of a combustible ignition chemical. 
     
     
         30 . The ignition apparatus of  claim 29 , wherein the controller comprises a pipe manifold in fluid communication with the coiled tubing and ignition chemical, ignition fuel and/or oxidant sources. 
     
     
         31 . The ignition apparatus of  claim 29  or  30 , wherein the controller is operable remotely from the ignition tool to (1) control the ignition fuel/ignition chemical and oxidant ratio of the mixture, (2) monitor combustion of the mixture, and (3) control the supply of electrical energy to the ignition. 
     
     
         32 . A method of igniting an underground coal seam from within a well channel that extends through the seam, said method comprising the steps of
 (1) moving an ignition tool of an ignition apparatus into the well channel; and   (2) igniting the underground coal seam at one or more locations within the well channel using the ignition tool,   
       wherein the ignition apparatus comprises:
 an ignition system comprising ignition means and the ignition tool; and 
 a positioning system comprising coiled tubing connected to the ignition tool and extendible within the well channel to position the ignition tool at a said location within the well channel. 
 
     
     
         33 . The method of  claim 32 , wherein the ignition apparatus is as defined in any one of  claims 1  to  31 . 
     
     
         34 . The method of  claim 32  or  claim 33  further comprising a step of maintaining oxidant in the well channel at a level to support the combustion. 
     
     
         35 . The method of any one of  claims 32  to  34  further comprising a step of repositioning the ignition tool to a new ignition site in the well channel. 
     
     
         36 . An ignition system comprising ignition means and an ignition tool for igniting an underground coal seam. 
     
     
         37 . The ignition system of  claim 36 , having features as described in any one of  claims 1  to  31 . 
     
     
         38 . Ignition means for igniting an underground coal seam. 
     
     
         39 . The ignition means of  claim 38 , having features as described in any one of  claims 1  to  31 . 
     
     
         40 . An ignition tool for igniting an underground coal seam. 
     
     
         41 . The ignition tool of  claim 40 , having features as described in any one of  claims 1  to  31 . 
     
     
         42 . A positioning system comprising coiled tubing extendible within a well channel to position an ignition tool at a desired location within the well channel. 
     
     
         43 . The positioning system of  claim 42 , having features as described in any one of  claims 1  to  31 . 
     
     
         44 . An ignition system as defined in  claim 36 , ignition means as defined in  claim 38 , an ignition tool for igniting an underground coal seam as defined in  claim 40 , or a positioning system as defined in  claim 42 , and substantially as hereinbefore described in the written description including as shown in the figures.