An ignition device for an underground coal gasification process, and an underground coal gasification method for carrying out ignition by using the same. The ignition device comprises a conveying device, a cut-off device (7), an ignition detonator (6) and one or more fuel packs (5), all of which are sequentially connected. The multiple fuel packs are serially connected with each other. The conveying device is a coiled tubing/conjugation tube (12), or an integrated signal cable (21). The ignition detonator runs through one or more fuel packs and ignites the one or more fuel packs starting from the top of the device in a delayed manner. The cut-off device breaks off after the ignition detonator is started, so that ignition device components comprising the conveying device are at least withdrawn to a safe position. Each fuel pack comprises thermit and is used for igniting an underground coal seam (1) after the fuel pack is ignited.

In downhole tools and methods related to stimulation of subterranean formations are provided. The tools and methods utilize electrically ignitable propellant to generate gas downhole that is used to generate or enhance fractures. The electrically ignitable propellant can be ignited applying electrical power to a pair of electrodes associated with the propellant. Subsequently, the ignition can be halted by ceasing to supply the electrical power. Thus, allowing for the control of the amount and location of generated gas.

Methods of delivering reactive components to a geological formation disclosed herein include generating a plurality of microholes along a wellbore, the plurality of microholes comprising one or more openings, and the plurality of microholes are configured to connect the wellbore to the geological formation. Methods further include delivering the one or more reactive components to the plurality of microholes via a carrier fluid, wherein the one or more reactive components are configured to enable one or more chemical reactions to occur, and wherein the carrier fluid is configured to expand, and controlling a flow rate of the one or more reactive components based on whether a volume of the one or more reactive components delivered to the plurality of microholes is greater than a threshold volume.

Methods of delivering reactive components to a geological formation disclosed herein include generating a plurality of microholes along a wellbore, the plurality of microholes comprising one or more openings, and the plurality of microholes are configured to connect the wellbore to the geological formation. Methods further include delivering the one or more reactive components to the plurality of microholes via a carrier fluid, wherein the one or more reactive components are configured to enable one or more chemical reactions to occur, and wherein the carrier fluid is configured to expand, and controlling a flow rate of the one or more reactive components based on whether a volume of the one or more reactive components delivered to the plurality of microholes is greater than a threshold volume.

A method for treating a hydrocarbon bearing formation bounded by at least one nonbearing formation comprises inserting a tubular into a wellbore formed in the hydrocarbon bearing formation. The tubular defines proximal and distal ends and further has a sidewall defining inner and outer surfaces and a tubular bore, where an annulus is defined between the outer surface of the sidewall and the inner surface of the wellbore. A detonator is disposed in the annulus through at least a portion of the hydrocarbon bearing formation. A first fluid including a first explosive is pumped through the tubular bore into a selected portion of the annulus. An isolation material is inserted in the annulus between an entrance of the wellbore and the first explosive fluid. The explosive fluid is detonated with the detonator.

A method for treating a hydrocarbon bearing formation bounded by at least one nonbearing formation comprises inserting a tubular into a wellbore formed in the hydrocarbon bearing formation. The tubular defines proximal and distal ends and further has a sidewall defining inner and outer surfaces and a tubular bore, where an annulus is defined between the outer surface of the sidewall and the inner surface of the wellbore. A detonator is disposed in the annulus through at least a portion of the hydrocarbon bearing formation. A first fluid including a first explosive is pumped through the tubular bore into a selected portion of the annulus. An isolation material is inserted in the annulus between an entrance of the wellbore and the first explosive fluid. The explosive fluid is detonated with the detonator.

A method for shale gas exploitation includes performing horizontal drilling operation on an area to be constructed, forming a crack around a horizontal drill hole wall by shaped charge perforation; expanding the crack around a horizontal hole hydraulic fracturing, and extracting methane gas after a fracturing fluid is discharged; after methane gas is reduced, performing in-situ combustion explosion fracturing on the methane involved in horizontal drilling; thereafter continuing to expand the crack in the horizontal drill hole such that methane continues to seep out, and continuing extracting methane; repeating combustion explosion fracturing and extraction operations, so as to increase combustion explosion cracking permeability, and greatly enhance the exploitation effect of shale gas. The method is suitable for fracturing reconstruction of unconventional oil and gas reservoirs such as shale gas reservoirs, coal seam gas reservoirs and tight sandstone gas reservoirs.

A method for shale gas exploitation includes performing horizontal drilling operation on an area to be constructed, forming a crack around a horizontal drill hole wall by shaped charge perforation; expanding the crack around a horizontal hole hydraulic fracturing, and extracting methane gas after a fracturing fluid is discharged; after methane gas is reduced, performing in-situ combustion explosion fracturing on the methane involved in horizontal drilling; thereafter continuing to expand the crack in the horizontal drill hole such that methane continues to seep out, and continuing extracting methane; repeating combustion explosion fracturing and extraction operations, so as to increase combustion explosion cracking permeability, and greatly enhance the exploitation effect of shale gas. The method is suitable for fracturing reconstruction of unconventional oil and gas reservoirs such as shale gas reservoirs, coal seam gas reservoirs and tight sandstone gas reservoirs.

A method for underground mining in a rock body include drilling one or more service boreholes from at least one surface location into a subsurface rock body. A plurality of multilateral blast holes is drilled, branching from at least one of the one or more service boreholes into the subsurface rock body. The plurality of multilateral blast holes are each loaded with one or more explosive charges and one or more detonators. The one or more explosive charges and the one or more detonators are inserted from surface. The one or more explosive charges is detonated wirelessly to fragment the subsurface ore body. Fragmented rock is extracted via the one or more service boreholes, to surface.

A method for treating a hydrocarbon bearing formation bounded by at least one nonbearing formation comprises inserting a tubular into a wellbore formed in the hydrocarbon bearing formation. The tubular defines proximal and distal ends and further has a sidewall defining inner and outer surfaces and a tubular bore, where an annulus is defined between the outer surface of the sidewall and the inner surface of the wellbore. A detonator is disposed in the annulus through at least a portion of the hydrocarbon bearing formation. A first fluid including a first explosive is pumped through the tubular bore into a selected portion of the annulus. An isolation material is inserted in the annulus between an entrance of the wellbore and the first explosive fluid. The explosive fluid is detonated with the detonator.