WO2015000024A1 - Procédé de gazéification in situ de charbon enrichie en oxygène - Google Patents
Procédé de gazéification in situ de charbon enrichie en oxygène Download PDFInfo
- Publication number
- WO2015000024A1 WO2015000024A1 PCT/AU2014/000704 AU2014000704W WO2015000024A1 WO 2015000024 A1 WO2015000024 A1 WO 2015000024A1 AU 2014000704 W AU2014000704 W AU 2014000704W WO 2015000024 A1 WO2015000024 A1 WO 2015000024A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- wellbore
- injection
- metal casing
- well
- oxygen
- Prior art date
Links
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 title claims abstract description 75
- 239000001301 oxygen Substances 0.000 title claims abstract description 75
- 229910052760 oxygen Inorganic materials 0.000 title claims abstract description 75
- 238000000034 method Methods 0.000 title claims abstract description 31
- 238000002347 injection Methods 0.000 claims abstract description 125
- 239000007924 injection Substances 0.000 claims abstract description 125
- 239000003245 coal Substances 0.000 claims abstract description 59
- 229910052751 metal Inorganic materials 0.000 claims abstract description 49
- 239000002184 metal Substances 0.000 claims abstract description 49
- 239000007789 gas Substances 0.000 claims abstract description 24
- 238000004519 manufacturing process Methods 0.000 claims abstract description 22
- 238000002309 gasification Methods 0.000 claims abstract description 13
- 230000003247 decreasing effect Effects 0.000 claims abstract description 12
- 238000012544 monitoring process Methods 0.000 claims abstract description 10
- MYMOFIZGZYHOMD-UHFFFAOYSA-N Dioxygen Chemical compound O=O MYMOFIZGZYHOMD-UHFFFAOYSA-N 0.000 claims description 30
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 27
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 16
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 claims description 12
- 238000000576 coating method Methods 0.000 claims description 8
- 229910052757 nitrogen Inorganic materials 0.000 claims description 8
- MCMNRKCIXSYSNV-UHFFFAOYSA-N Zirconium dioxide Chemical compound O=[Zr]=O MCMNRKCIXSYSNV-UHFFFAOYSA-N 0.000 claims description 6
- 229910045601 alloy Inorganic materials 0.000 claims description 6
- 239000000956 alloy Substances 0.000 claims description 6
- 229910002092 carbon dioxide Inorganic materials 0.000 claims description 6
- 239000001569 carbon dioxide Substances 0.000 claims description 6
- 238000011144 upstream manufacturing Methods 0.000 claims description 6
- 239000003085 diluting agent Substances 0.000 claims description 5
- 229910000975 Carbon steel Inorganic materials 0.000 claims description 3
- 239000010962 carbon steel Substances 0.000 claims description 3
- 239000011253 protective coating Substances 0.000 claims description 3
- 239000010935 stainless steel Substances 0.000 claims description 3
- 229910001220 stainless steel Inorganic materials 0.000 claims description 3
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 2
- 229910000792 Monel Inorganic materials 0.000 claims description 2
- 229910052799 carbon Inorganic materials 0.000 claims description 2
- 238000005524 ceramic coating Methods 0.000 claims description 2
- 239000002131 composite material Substances 0.000 claims description 2
- 229910000856 hastalloy Inorganic materials 0.000 claims description 2
- 229910001026 inconel Inorganic materials 0.000 claims description 2
- 239000007800 oxidant agent Substances 0.000 description 8
- 230000001590 oxidative effect Effects 0.000 description 8
- 238000002485 combustion reaction Methods 0.000 description 6
- 238000010276 construction Methods 0.000 description 6
- 239000000446 fuel Substances 0.000 description 6
- 239000000463 material Substances 0.000 description 6
- 239000000126 substance Substances 0.000 description 6
- 239000000203 mixture Substances 0.000 description 5
- 238000013461 design Methods 0.000 description 4
- 239000007788 liquid Substances 0.000 description 4
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 4
- LALRXNPLTWZJIJ-UHFFFAOYSA-N triethylborane Chemical compound CCB(CC)CC LALRXNPLTWZJIJ-UHFFFAOYSA-N 0.000 description 4
- 239000004215 Carbon black (E152) Substances 0.000 description 3
- 238000001816 cooling Methods 0.000 description 3
- 229930195733 hydrocarbon Natural products 0.000 description 3
- 150000002430 hydrocarbons Chemical class 0.000 description 3
- 238000005259 measurement Methods 0.000 description 3
- 238000010791 quenching Methods 0.000 description 3
- 230000000171 quenching effect Effects 0.000 description 3
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 2
- ATUOYWHBWRKTHZ-UHFFFAOYSA-N Propane Chemical compound CCC ATUOYWHBWRKTHZ-UHFFFAOYSA-N 0.000 description 2
- 239000004568 cement Substances 0.000 description 2
- 239000000788 chromium alloy Substances 0.000 description 2
- 239000011248 coating agent Substances 0.000 description 2
- 229910052802 copper Inorganic materials 0.000 description 2
- 239000010949 copper Substances 0.000 description 2
- 239000012530 fluid Substances 0.000 description 2
- 239000003673 groundwater Substances 0.000 description 2
- 239000011261 inert gas Substances 0.000 description 2
- 238000002955 isolation Methods 0.000 description 2
- 229910001092 metal group alloy Inorganic materials 0.000 description 2
- 230000003287 optical effect Effects 0.000 description 2
- 238000000253 optical time-domain reflectometry Methods 0.000 description 2
- 238000000197 pyrolysis Methods 0.000 description 2
- 239000007787 solid Substances 0.000 description 2
- 229910000881 Cu alloy Inorganic materials 0.000 description 1
- ZOKXTWBITQBERF-UHFFFAOYSA-N Molybdenum Chemical compound [Mo] ZOKXTWBITQBERF-UHFFFAOYSA-N 0.000 description 1
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 description 1
- BLRPTPMANUNPDV-UHFFFAOYSA-N Silane Chemical compound [SiH4] BLRPTPMANUNPDV-UHFFFAOYSA-N 0.000 description 1
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 1
- 229910052783 alkali metal Inorganic materials 0.000 description 1
- 150000001340 alkali metals Chemical class 0.000 description 1
- 239000004411 aluminium Substances 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 230000000903 blocking effect Effects 0.000 description 1
- 239000012267 brine Substances 0.000 description 1
- 239000001273 butane Substances 0.000 description 1
- 229910052792 caesium Inorganic materials 0.000 description 1
- TVFDJXOCXUVLDH-UHFFFAOYSA-N caesium atom Chemical compound [Cs] TVFDJXOCXUVLDH-UHFFFAOYSA-N 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- -1 cesium) Chemical class 0.000 description 1
- 238000012824 chemical production Methods 0.000 description 1
- 229910017052 cobalt Inorganic materials 0.000 description 1
- 239000010941 cobalt Substances 0.000 description 1
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- 230000001276 controlling effect Effects 0.000 description 1
- YOCUPQPZWBBYIX-UHFFFAOYSA-N copper nickel Chemical compound [Ni].[Cu] YOCUPQPZWBBYIX-UHFFFAOYSA-N 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 229910003460 diamond Inorganic materials 0.000 description 1
- 239000010432 diamond Substances 0.000 description 1
- 238000005553 drilling Methods 0.000 description 1
- 230000005611 electricity Effects 0.000 description 1
- 230000007717 exclusion Effects 0.000 description 1
- 238000000605 extraction Methods 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 239000013505 freshwater Substances 0.000 description 1
- 238000011065 in-situ storage Methods 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 229910052750 molybdenum Inorganic materials 0.000 description 1
- 239000011733 molybdenum Substances 0.000 description 1
- IJDNQMDRQITEOD-UHFFFAOYSA-N n-butane Chemical compound CCCC IJDNQMDRQITEOD-UHFFFAOYSA-N 0.000 description 1
- OFBQJSOFQDEBGM-UHFFFAOYSA-N n-pentane Natural products CCCCC OFBQJSOFQDEBGM-UHFFFAOYSA-N 0.000 description 1
- 229910000623 nickel–chromium alloy Inorganic materials 0.000 description 1
- RVTZCBVAJQQJTK-UHFFFAOYSA-N oxygen(2-);zirconium(4+) Chemical compound [O-2].[O-2].[Zr+4] RVTZCBVAJQQJTK-UHFFFAOYSA-N 0.000 description 1
- 230000000737 periodic effect Effects 0.000 description 1
- 229910052698 phosphorus Inorganic materials 0.000 description 1
- 239000011574 phosphorus Substances 0.000 description 1
- 239000001294 propane Substances 0.000 description 1
- 238000005086 pumping Methods 0.000 description 1
- 229910052761 rare earth metal Inorganic materials 0.000 description 1
- 150000002910 rare earth metals Chemical class 0.000 description 1
- 238000011084 recovery Methods 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 229910000077 silane Inorganic materials 0.000 description 1
- 229910052710 silicon Inorganic materials 0.000 description 1
- 239000010703 silicon Substances 0.000 description 1
- HPALAKNZSZLMCH-UHFFFAOYSA-M sodium;chloride;hydrate Chemical compound O.[Na+].[Cl-] HPALAKNZSZLMCH-UHFFFAOYSA-M 0.000 description 1
- 238000005507 spraying Methods 0.000 description 1
- 239000002352 surface water Substances 0.000 description 1
- 238000003786 synthesis reaction Methods 0.000 description 1
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 description 1
- 229910052721 tungsten Inorganic materials 0.000 description 1
- 239000010937 tungsten Substances 0.000 description 1
- 239000008215 water for injection Substances 0.000 description 1
- 229910001928 zirconium oxide Inorganic materials 0.000 description 1
Classifications
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B43/00—Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells
- E21B43/295—Gasification of minerals, e.g. for producing mixtures of combustible gases
Definitions
- This invention relates to a method of carrying out underground coal gasification (UCG).
- UCG methods that include oxygen enriched burn back of a metal casing inserted into a wellbore that links an injection well and a production well in an underground coal gasifier are disclosed.
- Underground coal gasification is a process by which product gas is produced from a coal seam by combusting and gasifying the coal in situ in the presence of an oxidant.
- the product gas is typically referred to as synthesis gas or syngas and can be used as a feedstock for various applications, including clean fuels production, chemical production and electricity generation.
- Wells are drilled into the coal seam to allow for oxidant injection and product gas extraction.
- the wells are linked or extended to form a substantially horizontal wellbore (also referred to as an in-seam well channel) to facilitate oxidant injection, cavity development and product gas flow.
- the well allowing the injection of oxidant is called an injection well.
- the well from which product gas emerges is called a production well.
- Both horizontal and vertical well regions can be used for injection and production.
- Underground coal gasification may also utilise one or more vertical wells (e.g., a service well and an ignition well) located between the injection and production wells.
- a coal seam having injection and production wells with a substantially horizontal wellbore linking the two is typically referred to as an underground coal gasifier.
- the gasifier will have a combustion zone within which coal is combusted in the presence of an oxidant, a gasification zone located downstream of the
- combustion zone in which coal is gasified and partially oxidized to produce product gas
- a downstream pyrolysis zone in which pyrolysis of coal occurs.
- Hot product gas flows downstream from the gasification zone and exits the ground from a well head of the production well.
- a gasifier (gasification) cavity within the coal seam develops and grows in size.
- the product gas (raw syngas) generated by UCG typically includes syngas as well as other components, and the constituency will depend on various factors including the type of oxidant used for UCG (air or other oxidant, such as oxygen or oxygen-enriched air), water presence (both ground water and exogenous water), coal quality, and UCG operating temperature and pressure.
- An object of the present invention to provide a method for UCG that minimises one or more of the problems of the prior art.
- the invention provides a method of underground coal gasification in a coal seam provided with an injection well, a production well and a substantially horizontal wellbore linking the injection well and the production well, including the steps of: a) inserting a metal casing into the wellbore, b) injecting air into the wellbore, c) igniting the coal seam while continuing the injection of air into the wellbore, d) establishing an active gasifier cavity in the coal seam so as to produce UCG product gas, e) increasing downhole oxygen concentration to a level sufficient to ignite the metal casing inserted into the wellbore, f) monitoring burn back of the metal casing inserted into the wellbore, and g) decreasing downhole oxygen concentration until a desired rate of burn back of the metal casing inserted into the wellbore is achieved.
- the oxygen concentration can be decreased once the metal casing inserted into the wellbore has been burned back a desired distance within the wellbore.
- the coal seam is further provided with an ignition well.
- increasing downhole oxygen concentration includes injecting substantially pure oxygen through the injection well or a service well into the wellbore while continuing the injection of air into the wellbore through the injection well.
- increasing downhole oxygen concentration includes stopping the injection of air into the wellbore and injecting substantially pure oxygen through the injection well or a service well into the wellbore, and wherein carbon dioxide, nitrogen, and/or water are injected with the oxygen as diluent.
- increasing downhole oxygen concentration includes positioning an oxygen injection device in the wellbore and providing substantially pure oxygen to the injection device while continuing the injection of air into the wellbore through the injection well, wherein the injection device is positioned in the wellbore upstream of the active UCG cavity.
- increasing downhole oxygen concentration includes positioning an oxygen injection device in the wellbore and providing substantially pure oxygen to the injection device, and replacing the injection of air into the wellbore through the injection well with the injection of carbon dioxide, nitrogen, and/or water, wherein the injection device is positioned in the wellbore upstream of the active UCG cavity.
- the present invention relates to methods of UCG that include oxygen enriched wellbore casing burn back to eliminate the need for re-ignition of a coal seam following initial ignition of the seam.
- the invention provides a method of underground coal gasification in a coal seam provided with an injection well, a production well and a substantially horizontal wellbore linking the injection well and the production well, including the steps of: a) inserting a metal casing into the wellbore, b) injecting air into the wellbore through the injection well, c) igniting the coal seam while continuing the injection of air into the wellbore, d) establishing an active gasifier cavity in the coal seam so as to produce UCG product gas, e) increasing downhole oxygen concentration to a level sufficient to ignite the metal casing inserted into the wellbore, f) monitoring burn back of the metal casing inserted into the wellbore, and g) decreasing downhole oxygen concentration until a desired rate of burn back of the metal casing inserted into the wellbore is achieved.
- the step of decreasing downhole oxygen concentration can be practiced once the metal casing inserted into the wellbore has been burned back a desired distance within the wellbore. That is, the step of decreasing downhole oxygen concentration can be practiced in such a way as to favour either continuous burn back of the metal casing inserted into the wellbore (including at a variable rate) or intermittent discontinuous burn back of the casing.
- the UCG methods disclosed herein can include the use of any injection/production well (including linking wellbore) design, any arrangement of wells and any gasifier layout, including a knife edge layout or a linear layout.
- the size, shape and construction of the casing is selected to ensure that it can be installed into a wellbore of an underground coal gasifier and remains intact during service (i.e., it keeps the wellbore open).
- the casing is strong enough to be inserted into the wellbore using traditional drilling service equipment, as will be known to one of ordinary skill in the art.
- the casing (also referred to as a "well liner") can be of any suitable size, shape and construction and can be made of any suitable material or materials.
- Exemplary metals suitable for the casing include, but are not limited to, carbon steel, copper, or aluminium, and combinations thereof.
- the casing can be made of material that is resistant to high
- Exemplary metal and metal alloys resistant to high temperatures and suitable for the casing include, but are not limited to, stainless steel (and alloys thereof), chromium-nickel alloys (including those containing silicon, cobalt, tungsten, molybdenum, and microalloying elements such as nitrogen, and rare earth metals such as cesium),the Inconel ® (predominantly nickel-chromium alloys), Monel ® (predominantly nickel-copper alloys), and Hastelloy ® (predominantly nickel- containing alloys) families of high-performance alloys.
- the casing can be coated (e.g., via plasma coating) with a protective coating, including, for example, ceramic coatings, zirconia (zirconium oxide) coatings, alumina-zirconia coatings, and carbon composite coatings.
- a protective coating including, for example, ceramic coatings, zirconia (zirconium oxide) coatings, alumina-zirconia coatings, and carbon composite coatings.
- the casing can be of any suitable diameter and length. Typically, the casing will have an outside diameter of anywhere between about 5 to 10 inches, more preferably about 5 to 8 inches, and even more preferably about 5.5 to 7 inches.
- the casing can be of unitary construction or can include a plurality of connectable units (i.e., segments/sections).
- the casing or segments can be of any suitable length, including, metres, tens of metres, hundreds of metres, and
- casing segments can be connected together to form a full- length casing being tens of metres long, hundreds of metres long, or even several kilometres in length, depending on the length of the wellbore.
- Each casing segment can be, for example, about 1 to 10 metres in length, including about 3, 5, 6, 7, or 9 metres in length.
- the casing segments can be connected together in any suitable way.
- the ends of each segment can be threaded, and the full-length casing can include one or more threaded collars for connecting the ends of adjacent casing segments together.
- threaded collars can be made of metal, metal alloys, and ceramics resistant to high temperatures, and/or coated with a protective coating as discussed herein.
- the casing (including segments/sections thereof) can be manufactured in shapes and sizes to suit the specific application.
- the casing has a round cross-section to provide an annular passage, although other cross-section shapes are possible, as will be understood by one of ordinary skill in the art.
- the metal casing inserted into the wellbore includes one or more perforated sections.
- the perforations in such perforated sections of the metal casing can be of any suitable size, shape and arrangement as required to mitigate a number of technical and operational issues associated with a fully closed- in casing design.
- the perforations allow the ignition of a coal seam from within a wellbore using an ignition tool located within the casing to ignite the surrounding coal seam.
- perforations in the casing allow oxidant and water/steam to pass through the casing and contact the coal while preventing coal and ash from blocking the path of production gases.
- the perforations can be in periodic symmetry in both circumferential and axial directions.
- the perforations can be in the form of circular or other shaped holes (e.g., hexagonal or octagonal), or slots.
- the perforations can be, for example, circular having a diameter of about 10 mm to about 25 mm.
- the perforations can be in a rectangular or diamond-shaped grid pattern, or both, for example.
- the perforations are in a staggered arrangement (diamond spacing) as this provides the casing with the greatest structural integrity.
- the casing extends from adjacent a heel of the injection well to adjacent a heel of the production well.
- injecting air into the wellbore includes injecting air through the injection well (or a service well) into the wellbore.
- a source of air e.g., an air compressor
- injecting air into the wellbore includes injecting air through the injection well (or a service well) into the wellbore.
- a source of air e.g., an air compressor
- the step of igniting the coal seam preferably includes using an ignition tool, whereby an ignition tool that includes ignition means is inserted into the coal seam via an ignition well or the injection well. Once introduced into the coal seam, the ignition tool is used to ignite the coal seam and establish a combustion zone.
- Inserting (and positioning) the ignition tool can be achieved utilising coiled tubing connected to the tool and extendible within the ignition/injection well to position the tool at a desired location within the coal seam.
- the ignition tool can be connected to the coiled tubing in any suitable way.
- the ignition tool is connected to the coiled tubing in a fluid-tight manner.
- the ignition tool can be releasably (i.e., non-permanently) connected or permanently connected to the coiled tubing.
- the ignition tool is connected to an end of the coiled tubing by way of a quick connector (such as grapple, torque thru, dimple, etc.), screw thread, or weld.
- the coiled tubing can be of any suitable size, shape and construction and can be made of any suitable material or materials. More particularly, the coiled tubing can be of any suitable length and diameter. Preferably, the coiled tubing is made of metal, such as stainless steel, carbon steel, or copper. The coiled tubing can be of unitary construction or can include two or more connectable tube pieces. A preferred outside diameter for the coiled tubing is 1.75 to 3.5 inches. The coiled tubing can be maintained on a spool from which the coiled tubing is unspooled. [0038] The ignition tool can ignite the coal seam in any suitable way.
- the ignition tool can directly ignite the coal seam at the perforations in the one or more perforated sections of the metal casing inserted into the wellbore, or ignite a combustible fuel (i.e., an ignition fuel) supplied to the ignition well (e.g., supplied as a gas, liquid, or solid).
- a combustible fuel i.e., an ignition fuel
- Suitable ignition fuels include, but are not limited to, hydrocarbon gases, for example, methane, propane, butane, and mixtures thereof.
- ignition means includes an electrical spark generator (e.g., a spark plug) or an electrical heat resistor (e.g., a glow plug) and a power supply for generating the spark/electrifying the resistor.
- Ignition means further include at least one type of ignition chemical.
- the ignition chemical can be a pyrophoric substance (e.g., a liquid, such as triethylboron (TEB), a gas, such as silane, a solid, such as phosphorus or an alkali metal), a pyrophoric substance and a hydrocarbon mixture, such as TEB vaporised in methane, or a pyrophoric substance and an inert gas, such as TEB and nitrogen.
- a pyrophoric substance e.g., a liquid, such as triethylboron (TEB), a gas, such as silane, a solid, such as phosphorus or an alkali metal
- a pyrophoric substance and a hydrocarbon mixture such as TEB vaporised in methane
- an inert gas such as TEB and nitrogen.
- the hydrocarbon or inert gas flow can help transport vaporise the pyrophoric substance to the ignition tool.
- the ignition tool is retracted a safe distance while continuing the injection of air into the wellbore (e.g., through the injection or a service well into the wellbore) to fuel/maintain combustion of the coal seam.
- the ignition tool can be withdrawn from the coal seam following successful ignition of the seam.
- the ignition tool is a sacrificial ignition tool that is consumed during the ignition/gasification process.
- composition of the product gas e.g., the calorific value and/or the H 2 to CO ratio emerging from the production well.
- the step of increasing downhole oxygen concentration (in the wellbore) to a level sufficient to ignite (or combust/oxidize) the metal casing inserted into the wellbore can be achieved in any suitable manner.
- increasing downhole oxygen concentration includes injecting substantially pure oxygen through the injection well (or a service well) into the wellbore while continuing the injection of air into the wellbore through the injection well.
- a source of substantially pure oxygen can be connected directly or indirectly to a well head of the injection well/service well, such that the oxygen is injected/introduced into the wellbore via the injection well/service well.
- increasing downhole oxygen concentration can be achieved by stopping the injection of air into the wellbore and injecting substantially pure oxygen through the injection well (or a service well) into the wellbore, with an inert liquid or gas (e.g., carbon dioxide, nitrogen and combinations thereof), and/or water being injected along with the oxygen as a diluent.
- an inert liquid or gas e.g., carbon dioxide, nitrogen and combinations thereof
- sources of substantially pure oxygen and a diluent can be connected directly or indirectly to a well head of the injection well/service well, such that the oxygen and diluent are injected/introduced into the wellbore via the injection well/service well.
- increasing downhole oxygen concentration includes positioning an oxygen injection device in the wellbore (via the injection well or a service well) and providing substantially pure oxygen to the injection device for delivery (e.g., injection) to the wellbore while continuing the injection of air into the wellbore through the injection well (or a service well).
- the oxygen injection device can provide directed/projected oxygen injection to the underground coal seam.
- the oxygen injection device includes an associated sacrificial ignition tool that is consumed during the ignition/gasification process (in which case the oxygen injection device is positioned in the wellbore prior to the ignition of the coal seam).
- the oxygen injection device is positioned in the wellbore upstream of the active UCG cavity (or upstream of where an active UCG cavity will be formed).
- the oxygen injection device can be positionable and retractable.
- increasing downhole oxygen concentration can be achieved by positioning the oxygen injection device in the wellbore (via the injection well or a service well) and providing substantially pure oxygen to the injection device for delivery (e.g., injection) to the wellbore as described herein, while replacing the injection of air into the wellbore through the injection well (or a service well) with the injection of an inert liquid or gas (e.g., carbon dioxide, nitrogen and combinations thereof), and/or water.
- an inert liquid or gas e.g., carbon dioxide, nitrogen and combinations thereof
- positioning of the oxygen injection device can be achieved utilising coiled tubing connected to the oxygen injection device and extendible within the wellbore to position the oxygen injection device at a desired location within the wellbore.
- the source of the substantially pure oxygen can be connected directly or indirectly to the coiled tubing associated with the oxygen injection device in a fluid-tight manner, for introduction of the substantially pure oxygen into the wellbore via the oxygen injection device.
- coiled tubing can include at least one inner tube (inner line) extending within an outer tube (outer line), wherein one or both of the inner and outer tubes are connected to an oxygen injection device with associated sacrificial ignition tool (e.g., with one tube supplying an ignition fuel and the other tube facilitating injection of substantially pure oxygen into the coal seam). That is, the coiled tubing can include at least one inner tube and an outer tube that extend concentrically relative to one another. More than one inner tube may extend within the same outer tube.
- concentration can be provided via a tank/cylinder of compressed oxygen, an air separation unit, or a tank/cylinder of liquid oxygen, for example.
- the oxygen injection device is positionable and retractable.
- the coiled tubing and oxygen injection device can be drawn along the cased wellbore that extends through the coal seam.
- a preferred method is utilising the controlled retracting injection point (CRIP) concept, as will be understood by one of ordinary skill in the art.
- retracting the oxygen injection device positioned in the wellbore (continuously or intermittently) in the direction of the injection well/service well causes the active UCG cavity to burn towards the oxygen injection device. Accordingly, re-ignition of the coal seam is not necessary to continue the UCG process.
- the oxygen injection device can include a controller operable to control the release/injection of substantially pure oxygen.
- the controller can include a pipe manifold in fluid communication with the coiled tubing and substantially pure oxygen source.
- the controller can be operated remotely from the oxygen injection device.
- the controller can include trim, non-return, and isolation valves, flow measuring devices, and pressure relief devices. Such operating devices allow for injection rate measurement and control of substantially pure oxygen.
- Substantially pure oxygen injection rate and quantity can be adjusted using flow controlling devices, such devices being either pneumatically actuated, manually choked, quarter-turn types, or electrically actuated.
- the controller can include pressure safety devices, filtration devices, and flow metering devices, in addition to isolation valves. Control logic can allow the substantially pure oxygen to flow as per the required settings.
- the source of substantially pure oxygen can be connected to a pipe manifold of the controller and further to the coiled tubing and a well head of an injection well (or a service well).
- a power supply e.g., generator
- a power supply can be electrically connected to the controller and further to an electrical cable and sensor cable extending through the coiled tubing.
- substantially pure oxygen can be injected at any suitable injection rate and quantity.
- the injection rate can be chosen with respect to various design criteria, including ensuring that the rate of casing burn-back and/or the quality and/or composition of the product gas (e.g., the calorific value and/or the H 2 to CO ratio) emerging from the production well are as desired.
- the product gas e.g., the calorific value and/or the H 2 to CO ratio
- One of ordinary skill in the art will be able to formulate the rate and quantity of substantially pure oxygen injection necessary to achieve desired outcomes.
- Injection of substantially pure oxygen into the wellbore via the injection well and/or the oxygen injection device is carried out to achieve downhole oxygen enrichment in the range of about 30 mol% to about 100 mol%, including about 35 mol%, about 40 mol%, about 45 mol%, about 50 mol%, about 55 mol%, about 60 mol%, about 65 mol%, about 70 mol%, about 75 mol%, about 80 mol%, about 85 mol%, about 90 mol%, and about 95 mol%.
- the step of monitoring burn back of the metal casing inserted into the wellbore can be achieved using instrumentation associated with the casing.
- instrumentation associated with the casing.
- Any suitable type of instrumentation can be used.
- suitable instrumentation can include one or more conducting wires and/or thermocouples attached to the outside or the inside of the metal casing, to facilitate continuous length
- suitable instrumentation can include one or more optical fibres attached to the outside or the inside of the metal casing to facilitate optical time domain reflectometry (OTDR) for continuous length measurements of the casing.
- OTDR optical time domain reflectometry
- the steps of increasing downhole oxygen concentration to a level sufficient to ignite the metal casing inserted into the wellbore, monitoring burn back of the metal casing inserted into the wellbore, and decreasing downhole oxygen concentration once the metal casing inserted into the wellbore has been burned back a desired distance within the wellbore can be repeated as needed to further burn back the metal casing inserted into the wellbore.
- the steps of increasing downhole oxygen concentration to a level sufficient to ignite the metal casing inserted into the wellbore, monitoring burn back of the metal casing inserted into the wellbore, and decreasing downhole oxygen concentration once the metal casing inserted into the wellbore has been burned back a desired distance within the wellbore can be automated to facilitate repetition of these steps.
- the step of monitoring burn back of the metal casing inserted into the wellbore can be achieved by monitoring the quality and/or composition of the product gas (e.g., the calorific value and/or the H 2 to CO ratio) emerging from the production well.
- the product gas e.g., the calorific value and/or the H 2 to CO ratio
- the step of decreasing downhole oxygen concentration can include halting the injection of substantially pure oxygen through the injection well/service well or via the oxygen injection device into the wellbore.
- the metal casing inserted into the wellbore is cemented into place in the wellbore.
- cementing the metal casing into the wellbore influences casing burn back, including casing ignition and burn back rate.
- the cement when cementing the metal casing into the wellbore the cement can be inserted into the space between the wellbore and the casing by pouring and/or pumping the cement into the desired space.
- localised downhole water cooling/quenching can be used to influence casing burn back, including casing ignition and burn back rate.
- Water for injection can be obtained from a naturally occurring water source, such as surface water or ground water.
- the water can be either fresh water or brine.
- the water can be treated water, such as demineralised water or raw water separated from UCG product gas.
- water can be injected at any suitable injection rate and quantity.
- the injection rate can be chosen with respect to various design criteria, including ensuring that injection of water is sufficient to maintain downhole well/wellbore temperatures within a desired range.
- One of ordinary skill in the art will be able to formulate the rate and quantity of water injection necessary to achieve desired outcomes relating to casing bum back, including casing ignition and burn back rate.
- downhole water cooling/quenching can be carried out using a water delivery system to deliver the water, and this can be of any suitable size, shape, and construction.
- the water delivery system can include tubing for conveying the water, and optionally a nozzle or pig tail fitted to a lower end of the tubing for spraying the water into the cased wellbore in the area where
- This type of delivery system can be extended to the desired position within the cased wellbore via a service well.
- the tubing can be flexible, such that it can be unwound from a spool.
- the water delivery system can further include a circulation pump and fluid reservoir connected to the upper end of the tubing.
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- Mining & Mineral Resources (AREA)
- Physics & Mathematics (AREA)
- Environmental & Geological Engineering (AREA)
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Abstract
L'invention concerne un procédé de réalisation de gazéification in situ de charbon enrichie en oxygène (UCG). Le procédé de gazéification in situ de charbon dans un filon de charbon équipé d'un puits d'injection, d'un puits de production et d'un puits de forage substantiellement horizontal reliant le puits d'injection et le puits de production, comprend les étapes consistant à : (a) introduire un carter métallique dans le puits de forage ; (b) injecter de l'air dans le puits de forage à travers le puits d'injection ; (c) enflammer le filon de charbon tout en poursuivant l'injection d'air dans le puits de forage ; (d) établir une cavité de gazéification active dans le filon de charbon de façon à produire du gaz de produit d'UCG ; (e) augmenter la concentration en oxygène de fond de trou à un taux suffisant pour enflammer le carter métallique introduit dans le puits de forage ; (f) surveiller la réinflammation du carter métallique introduit dans le puits de forage ; et (g) diminuer la concentration en oxygène de fond de trou jusqu'à ce qu'un taux souhaité de réinflammation du carter métallique introduit dans le puits de forage soit atteint.
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AU2016100004A AU2016100004A4 (en) | 2013-07-05 | 2016-01-05 | Oxygen enriched ucg method |
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AU2013902538 | 2013-07-05 | ||
AU2013902538A AU2013902538A0 (en) | 2013-07-05 | Oxygen enriched ucg method |
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AU2016100004A Division AU2016100004A4 (en) | 2013-07-05 | 2016-01-05 | Oxygen enriched ucg method |
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PCT/AU2014/000704 WO2015000024A1 (fr) | 2013-07-05 | 2014-07-04 | Procédé de gazéification in situ de charbon enrichie en oxygène |
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Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB762484A (en) * | 1953-08-26 | 1956-11-28 | Mini Of Fuel And Power | Improvements relating to the underground gasification of coal |
US4436153A (en) * | 1981-12-31 | 1984-03-13 | Standard Oil Company | In-situ combustion method for controlled thermal linking of wells |
CN102094615A (zh) * | 2010-12-17 | 2011-06-15 | 中国石油集团长城钻探工程有限公司 | 煤层气水平井热力筛管完井方法 |
-
2014
- 2014-07-04 WO PCT/AU2014/000704 patent/WO2015000024A1/fr active Application Filing
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB762484A (en) * | 1953-08-26 | 1956-11-28 | Mini Of Fuel And Power | Improvements relating to the underground gasification of coal |
US4436153A (en) * | 1981-12-31 | 1984-03-13 | Standard Oil Company | In-situ combustion method for controlled thermal linking of wells |
CN102094615A (zh) * | 2010-12-17 | 2011-06-15 | 中国石油集团长城钻探工程有限公司 | 煤层气水平井热力筛管完井方法 |
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