CN109025950B - Fiber laser ignition system for underground coal gasification process and operation method thereof - Google Patents
Fiber laser ignition system for underground coal gasification process and operation method thereof Download PDFInfo
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- CN109025950B CN109025950B CN201811090784.6A CN201811090784A CN109025950B CN 109025950 B CN109025950 B CN 109025950B CN 201811090784 A CN201811090784 A CN 201811090784A CN 109025950 B CN109025950 B CN 109025950B
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- 239000000835 fiber Substances 0.000 title claims abstract description 84
- 238000000034 method Methods 0.000 title claims abstract description 79
- 238000002309 gasification Methods 0.000 title claims abstract description 60
- 238000002347 injection Methods 0.000 claims abstract description 87
- 239000007924 injection Substances 0.000 claims abstract description 87
- 239000013307 optical fiber Substances 0.000 claims abstract description 57
- 239000007800 oxidant agent Substances 0.000 claims abstract description 51
- 230000001590 oxidative effect Effects 0.000 claims abstract description 45
- 230000005540 biological transmission Effects 0.000 claims abstract description 6
- 239000012159 carrier gas Substances 0.000 claims description 27
- 238000009434 installation Methods 0.000 claims description 22
- 239000003570 air Substances 0.000 claims description 15
- 230000003068 static effect Effects 0.000 claims description 14
- 238000010304 firing Methods 0.000 claims description 12
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- 239000001569 carbon dioxide Substances 0.000 claims description 3
- 229910002092 carbon dioxide Inorganic materials 0.000 claims description 3
- UBAZGMLMVVQSCD-UHFFFAOYSA-N carbon dioxide;molecular oxygen Chemical compound O=O.O=C=O UBAZGMLMVVQSCD-UHFFFAOYSA-N 0.000 claims description 3
- 229910052757 nitrogen Inorganic materials 0.000 claims description 3
- MYMOFIZGZYHOMD-UHFFFAOYSA-N Dioxygen Chemical compound O=O MYMOFIZGZYHOMD-UHFFFAOYSA-N 0.000 claims description 2
- JCXJVPUVTGWSNB-UHFFFAOYSA-N nitrogen dioxide Inorganic materials O=[N]=O JCXJVPUVTGWSNB-UHFFFAOYSA-N 0.000 claims description 2
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- 238000002485 combustion reaction Methods 0.000 description 6
- 230000015572 biosynthetic process Effects 0.000 description 5
- 239000000463 material Substances 0.000 description 4
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- 229910000570 Cupronickel Inorganic materials 0.000 description 1
- 229910000885 Dual-phase steel Inorganic materials 0.000 description 1
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 1
- 229910001030 Iron–nickel alloy Inorganic materials 0.000 description 1
- 229910000792 Monel Inorganic materials 0.000 description 1
- 229910001080 W alloy Inorganic materials 0.000 description 1
- 230000002159 abnormal effect Effects 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
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- 238000012824 chemical production Methods 0.000 description 1
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- 239000011280 coal tar Substances 0.000 description 1
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- 239000000446 fuel Substances 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
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- 239000001257 hydrogen Substances 0.000 description 1
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Classifications
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- 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
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- Life Sciences & Earth Sciences (AREA)
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- Mining & Mineral Resources (AREA)
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- Environmental & Geological Engineering (AREA)
- Fluid Mechanics (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Geochemistry & Mineralogy (AREA)
- Laser Beam Processing (AREA)
- Light Guides In General And Applications Therefor (AREA)
Abstract
The invention provides a fiber laser ignition system for an underground coal gasification process (ISC), which comprises the following components: an on-board unit including a generator or power supply for providing the energy required for ignition, and a laser source for converting electrical energy into laser light; one or more armored fiber optic cable strings for laser transmission, dynamically installed within the coiled tubing unit, transported through the coiled tubing to a desired ignition point location or statically installed at an injection well liner/injection well casing predetermined ignition point location, including a first ignition point location and a subsequent pre-designed ignition point location; the optical fiber laser head is used for guiding and igniting a target coal seam by laser, and is corresponding to the optical fiber cable string, and is dynamically and directly fixed at the tail end of the oxidant conveying equipment in the continuous oil pipe unit or is statically and directly fixed at the tail end of the armored optical fiber cable string outside the liner tube/sleeve of the injection well; the on-board unit is connected with the optical fiber cable string through a quick connector or an optical fiber slip ring.
Description
Technical Field
The invention provides a fiber laser ignition system for an underground coal gasification process (ISC) and an operation method. In particular, the invention provides a fiber laser ignition system capable of performing multiple ignition in a coal underground gasification process, and also provides an operation method of the fiber laser ignition system in the coal underground gasification process, which can be particularly used for primary ignition, secondary ignition and multiple ignition processes in the coal underground gasification process.
Background
Underground coal gasification (ISC) is a process in which coal is directly converted into product gas, commonly referred to as synthesis gas, by combustion and gasification reactions in an underground coal seam in the presence of an oxidant, which can then be used as a feedstock for a variety of applications, including fuel production, chemical production, power generation, and the like. This underground coal gasification technology is applicable to most coal reservoirs. This technique is clearly attractive in view of the increasingly stringent environmental requirements associated with the mining industry and in view of the associated labor and capital costs. Coal gasification processes are processes in which coal is converted to synthesis gas by a series of chemical reactions. The main reactions include:
C+O 2 →CO 2 (complete Oxidation reaction)
C+1/2O 2 CO (partial oxidation reaction)
C+H 2 O→H 2 +CO (steam gasification reaction)
C+2H 2 →CH 4 (Hydrogen gasification reaction)
C+CO 2 2CO (carbon dioxide gasification reaction)
The ground well is drilled through the coal seam to provide an effective channel for oxidant injection and product gas production. A pair of wells are connected or extend horizontally in the subsurface to form a substantially horizontal well path (also referred to simply as a coal seam well or connecting path). The channels facilitate oxidant injection, goaf growth and product gas transport. One well for oxidant injection is called an "injection well", and the other well for production of product gas is called a "production well". Both directional horizontal drilling and vertical drilling may be used as injection wells or production wells. Underground coal gasification (ISC) may also require the use of one or more vertical wells (e.g., functional and auxiliary wells) between the injection well and the production well.
When there are injection wells, production wells, and horizontal channels in the coal seam connecting the two, this configuration is referred to as a coal underground gasification (ISC) unit or well pair. The ISC unit includes a combustion zone, a gasification zone, and a pyrolysis zone. Wherein the combustion zone is near an oxidant injection point in the coal seam; the gasification zone surrounds the combustion zone in a radial form or is arranged downstream of the combustion zone, and coal is gasified and partially oxidized in the gasification zone, so that product gas is generated; downstream of the gasification zone, the pyrolysis zone where the pyrolysis reaction of the coal generally occurs. The high temperature product gas flows downstream from the gasification zone and is ultimately delivered from the product wellhead to the surface. At the same time as the coal burns or gasifies, ISC goaf growth in the coal seam may become large.
The product gas (raw synthesis gas) produced by underground gasification of coal generally contains synthesis gas (CO, CO) 2 ，H 2 ，CH 4 And other gases) and other ingredients, solid particles, water, coal tar, hydrocarbon vapors, other minor components including H 2 S，NH 4 COS, etc.). The composition complexity depends on several aspects: the oxidizing agent (air or other oxidizing agent such as oxygen, oxygen enriched air or steam mixtures) used in the underground gasification of coal, the water in the coal seam or water in the surrounding formation penetrating the coal seam, the coal quality, and the operating parameters of the underground gasification process of coal, including temperature, pressure, etc.
According to the prior patent literature, the problems faced by the existing underground coal gasification technology mainly comprise:
a) A safe, reliable and cost effective ignition device for initial and subsequent re-ignition of a coal seam.
b) Many of the ignition systems and methods in the prior art patents are impractical/impossible when the distance is long or the well depth is deep, e.g. an electrical heating element may cause a voltage drop due to too many conductors when the distance is too long. Inflammable and explosive ignition devices also continue to present many challenges in terms of material handling and activation.
c) Most conventional systems require more specialized operations to be performed from the main oxygen therapy facility or multiple wells (cable, junction tubing, E-line, coiled tubing) to achieve ignition.
d) Insufficient heat is provided to overcome the heat loss of combustion of the liner/casing itself and it is difficult to focus the heat directly at the target coal seam, resulting in significant difficulty in multiple ignitions within the liner/casing.
Disclosure of Invention
Aiming at the defects of the prior art, the invention provides a fiber laser ignition system used in the underground coal gasification process and also provides an operation method of the ignition system in a single or multiple ignition stages of the underground coal gasification process.
The technical scheme adopted for solving the technical problems is as follows:
a fiber laser ignition system for an underground coal gasification process based on an injection well liner or injection well casing as a moving channel, the fiber laser ignition system comprising the following components:
an on-board unit including a generator or power supply for providing the energy required for ignition, and a laser source for converting electrical energy into laser light;
one or more dynamically or statically mounted armored fiber optic cable strings for transmission of laser light;
a) The device is arranged in the continuous oil pipe unit, and is conveyed to a position of a required ignition point through the continuous oil pipe, so that the device is called dynamic installation;
b) Is installed at a predetermined firing point location of the injector liner/injector casing, including the location of the first firing point and subsequent pre-designed firing point locations, referred to as a static installation;
and a dynamically or statically mounted optical fiber laser head for guiding and igniting the target coal seam.
a) Dynamic installation: and the oxidant conveying equipment end is directly arranged in the continuous oil pipe unit.
b) Static mounting: the end of the armored fiber optic cable string that is mounted directly on the outside of the injection well liner/injection well casing.
The on-board unit and the optical fiber cable string in the optical fiber laser ignition system are connected through the quick connector or the optical fiber slip ring. When dynamic installation is adopted, the fiber optic cable string is connected with an oxidant conveying device in the coiled tubing unit through a quick connector, and the oxidant conveying device and the fiber optic laser head are connected in a non-welding mode through an external grapple connector or a quick connector or threads with bayonet/positioning bolts or flange bolts and provide effective airtight sealing. That is, the optical fiber cable string is installed inside the continuous oil pipe, the tail end of the continuous oil pipe is provided with an oxidant conveying device, the oxidant conveying device is connected to the tail end of the continuous oil pipe, the optical fiber laser head is installed at the tail end of the oxidant conveying device, and the optical fiber cable string passes through the oxidant conveying device by adopting a grapple or a quick connector. When static installation is adopted, the fiber cable string is directly connected with the fiber laser head through a quick connector and is fixed on the outer side of the injection well liner/injection well sleeve.
The optical fiber laser head can adopt air, oxygen-enriched air, oxygen, carbon dioxide or nitrogen as auxiliary guide carrier gas of laser, and the oxidant in the gasification process can adopt air, oxygen-enriched air or oxygen. Wherein, the conveying channels for guiding carrier gas and oxidant are: and a coiled tubing internal passage, an annular gap between the coiled tubing and the injection well liner/injection well casing, and an annular gap between the injection well liner/injection well casing and the coal seam drilling.
The operation method of the fiber laser ignition system is based on a well completion system provided with an ISC well pair in an underground coal bed, and comprises the following steps:
1. the dynamic installation ignition method comprises the following steps:
a. pushing the optical fiber laser head to a preset ignition position through the continuous oil pipe;
b. injecting guide carrier gas through the continuous oil pipe, and adjusting the direction of the optical fiber laser head to a preset coal bed position;
c. injecting an oxidant through the coiled tubing and the annulus passage of the injection well liner/injection well casing;
d. starting an optical fiber laser ignition system through a ground vehicle-mounted power supply to perform underground coal seam ignition;
e. after successful ignition, the equipment is retracted to a safe position;
f. injecting oxidant through the continuous oil pipe to gasify coal underground;
g. and (3) performing secondary or multiple ignition by repeating the steps a-f until all coal deposits along the direction of the lining pipe of the injection well are consumed.
2. Static installation ignition method:
a. a plurality of optical fiber laser heads are arranged at the preset coal seam ignition positions;
b. injecting guide carrier gas through an annular gap channel of the injection well liner tube/injection well sleeve tube and the coal seam drilling hole, and adjusting the direction of the optical fiber laser head to a preset coal seam position;
c. injecting an oxidant through the injection well liner/injection well casing internal passage;
d. starting an optical fiber laser ignition system through a ground vehicle-mounted power supply to perform underground coal seam ignition;
e. increasing the injection flow and pressure of the oxidant, and implementing underground coal gasification;
f. and (3) performing secondary or multiple ignition by repeating the steps a-e until all coal deposits along the direction of the lining pipe of the injection well are consumed.
The invention has the beneficial effects that:
according to the underground coal gasification method, under the condition that the ignition stage is failed or the coal seam is interrupted in the gasification process and continuous gasification cannot be performed, the ignition equipment can be used for re-ignition, including secondary ignition and multiple ignition, until the coal seam is re-ignited, so that the final implementation of the underground coal gasification process is ensured.
According to the invention, when the optical fiber laser ignition system is utilized to carry out the underground coal gasification process, the secondary and multiple ignition processes are not needed to be directly implemented under the condition of interrupting the underground coal gasification process, and the process operation is more flexible and convenient, so that the continuous and stable operation of the underground coal gasification process is realized, and the progress is brought to the prior art.
Drawings
FIG. 1 is a schematic diagram of a complete dynamic fiber laser ignition system including a laser source, coiled tubing unit and downhole equipment assembly, and details of the downhole environment showing an injector well liner/injector well casing and coal seam.
FIG. 2 is a schematic diagram of a complete static laser ignition system;
fig. 3 is a schematic view of the internal rotating head of an optical fiber laser head.
Like reference symbols in the various drawings indicate like elements. Specifically, reference numerals referred to in the drawings have the following meanings:
1. generator/power source, 2. Laser source, 3. Fiber optic cable, 4. Quick connector or fiber optic slip ring, 5. Coiled tubing unit, 6. Coiled tubing (including fiber optic cable and other service equipment), 7. Wellhead, 8. Injection well casing/injection well liner, 9. Coiled tubing downhole section, 10. Coal seam, 11. Complete downhole laser equipment cross-sectional view, 12. Detailed exploded cross-sectional view of laser equipment, 13. Laser beam, 14. Spring cover/trap door, 15. Reflector/mirror, 16. Flow path of oxidant, 17. Flow path of laser and pilot gas, 18. Laser lens, 19. Rotatable laser head body, 20. Rotary actuator, 21. Fiber optic cable (fixedly mounted to injection well casing/injection well liner), 22. First ignition point, 23. Second ignition point, 24. Multiple/last ignition point, 25, 26, drive gear, 27, brake pin, 28, spring blade.
Detailed Description
The technical scheme of the invention is further specifically described below through specific embodiments and with reference to the accompanying drawings.
A fiber laser ignition system for an underground coal gasification process based on an injection well liner/injection well casing as a moving channel, the fiber laser ignition system comprising the following components:
1. an on-board unit including a generator/power supply for providing the energy required for ignition, a laser source for converting electrical energy into laser light;
2. one or more armored fiber optic cable strings for laser transmission may be respectively:
2a) The device is arranged in the continuous oil pipe unit, and is conveyed to a position of a required ignition point through the continuous oil pipe, so that the device is called dynamic installation;
2b) Is installed at a predetermined firing point location of the injector liner/injector casing, including the location of the first firing point and subsequent pre-designed firing point locations, referred to as a static installation;
3. an optical fiber laser head for guiding laser and igniting target coal seam, which can respectively:
3a) Dynamic installation: the oxidant delivery means according to 2 a) above is mounted directly at the end of the oxidant delivery means in the coiled tubing unit.
3b) Static mounting: the armored fiber optic cable string according to 2 b) above, mounted directly outside the injection well liner/injection well casing.
For completion systems for ISC well pairs in coal underground gasification processes, injection well liners/injection well casings are an important component, being an important passageway for the flow of fluids during ignition and gasification processes in the coal underground gasification process. According to the invention, the injection well liner is a sacrificial consumable, typically carbon steel or a material thereof, that meets operating environment requirements. Meanwhile, according to the property of the coolant, the inner wall of the lining pipe of the injection well needs to be subjected to corrosion-resistant treatment to a certain extent. The size of the liner in the injection well is typically 4.5, 5.0, 5.5, 6.0, 6.625, or 7.0 inches. The pipe wall thickness (inner diameter) can be selected according to the static rock pressure, the static water pressure, the flow of the coolant and the like. The connection mode of the liner tube in the injection well takes the final completion performance as the highest priority, and can be selected from welding connection, threaded connection, clamp groove connection, flange connection, clamping sleeve connection, clamping and pressing connection and the like.
The vehicle-mounted unit in the technical scheme of the invention comprises a generator/power supply and a laser source. Wherein the generator/power supply is used to provide the energy required for ignition and the laser source is used to convert electrical energy into laser light. The vehicle-mounted mode is convenient to move among a plurality of underground gasification furnace groups or ISC well pairs, and ignition service is implemented for large-scale coal underground projects. During field operations, it will be easier to reuse the equipment when the on-board unit is relocated to a new well pair location.
The vehicle-mounted unit and one or more armored fiber optic cable strings in the technical scheme of the invention are connected through a quick connector or an optical fiber slip ring. Wherein the one or more armored fiber optic cable strings comprise at least three armor protective sheaths, such as stainless steel 316L, aluminum and nichrome 825, and a hydrogen-blocking solvent, such as a gel-free hydrogen-blocking paste. Meanwhile, a continuous pipe with a thicker wall thickness can be arranged on the armored fiber cable string according to the actual working condition so as to ensure that the fiber cable string is used in a high-temperature high-pressure pure oxygen environment. The armored fiber optic cable string typically has an outer diameter of 1/8-1 inch. Each fiber optic cable may provide 2-10kW of laser power. Preferably 2-5kw.
The installation mode of one or more armored fiber cable strings in the technical scheme of the invention is selected according to the underground coal gasification process. The optical fiber cable string is installed inside the continuous oil pipe by adopting dynamic installation and is conveyed to the position of a required ignition point through the continuous oil pipe; with static installation, the fiber optic cable string is installed at predetermined firing point locations of the injector liner/injector casing, including the location of the first firing point and subsequent pre-designed firing point locations.
The optical fiber laser head in the technical scheme is used for guiding and igniting the target coal seam by laser. The laser head can be repeatedly used after successful ignition by adopting dynamic installation, and special dual-phase steel materials with high temperature resistance and corrosion resistance, such as chromium-nickel-iron alloy, monel copper-nickel alloy, tungsten alloy and the like are selected; the laser head is statically installed, belongs to a consumable in the ignition process, and is made of common carbon steel and above materials.
The optical fiber laser head in the technical scheme of the invention comprises at least one mirror/reflector, a laser lens and a spring cover/trapdoor. Wherein the mirror/reflector is used for transferring and adjusting the emitting direction (small range) of the laser, the laser lens is used for adjusting the diameter and the area of the laser beam, and the spring cover/trapdoor is used for protecting the optical fiber laser head during the conveying process of the optical fiber laser ignition system.
Wherein the optical fiber laser head is mechanically rotated by an oxidant/guide carrier gas stream. The rotation can be adjusted to provide a circular motion (a large range) of part or all of the fiber laser head. The rotating head does not engage the gear assembly until the oxidant/carrier gas stream is directed. When the oxidant/carrier gas flow is activated, the fiber laser head is made to perform a 0-180 degree circular motion (preferably 30-120 degrees) by means of a fan blade and a gear transmission device, and the laser emission direction is adjusted to a predetermined ignition position. The fixed point ignition can be implemented by adjusting the operating pressure of the oxidant/carrier gas guiding air flow to push the bolt to implement braking and fixing the laser emitting direction. If the abnormal condition occurs underground, the laser emitting direction is not fixed, and the large-area ignition of 0-180-degree circular motion and the cutting of the injection well liner tube/injection well casing tube can be directly implemented.
The installation mode of the optical fiber laser head in the technical scheme of the invention is selected according to the underground coal gasification process. The dynamic installation is adopted, the optical fiber cable string is connected with oxidant conveying equipment in the continuous oil pipe unit through a quick connector, and the oxidant conveying equipment and the optical fiber laser head are connected in a non-welding way through an external grapple connector or a quick connector or threads with bayonet/positioning bolts or flange bolts and provide effective airtight sealing; by adopting static installation, the fiber cable string is directly connected with the fiber laser head through a quick connector and is fixed on the outer side of the injection well liner tube/injection well sleeve.
The optical fiber laser head in the technical scheme of the invention can adopt air, oxygen-enriched air, oxygen, carbon dioxide or nitrogen as auxiliary guide carrier gas of laser, and the oxidant in the gasification process can adopt air, oxygen-enriched air or oxygen. Wherein, the conveying channels for guiding carrier gas and oxidant are: and a coiled tubing internal passage, an annular gap between the coiled tubing and the injection well liner/injection well casing, and an annular gap between the injection well liner/injection well casing and the coal seam drilling.
According to the invention, in the fiber laser ignition system, after the fiber laser ignition system is started by a ground vehicle-mounted power supply, laser energy generated in the ignition process is enough to burn through the liner tube/the liner tube of the injection well, evaporate free water and intrinsic water in the coal layer at the ignition position, and raise the temperature of the coal layer to an ignition point, so that the ignition of the coal layer is finally realized. Meanwhile, the existence of the adjustable optical fiber laser head can directly adjust the laser to a preset ignition position, so that the energy consumed by evaporation of free water in the injection well liner tube/injection well sleeve in the ignition process is avoided. Therefore, according to the invention, in the fiber laser ignition system, the energy released by the fiber laser head, the ignition time and the like can be changed by adjusting the working time of the generator/power supply in the vehicle-mounted unit, so that the ignition process of underground coal gasification is optimized.
According to experimental measurements, a single fiber optic cable was used to deliver 2-10kW of laser light for about 10-40 seconds of ignition time sufficient to burn through the injector liner/injector casing and heat the coal seam to the ignition point. If four optical fiber cable strings are adopted to convey laser (8-40 kW), the ignition time is 5-20 seconds, the ignition point area of a coal bed and the hole burning area of an injection well liner tube/injection well sleeve tube can be improved by 3-4 times, and the ignition efficiency and quality in the underground coal gasification process are greatly improved.
The operation method of the fiber laser ignition system is based on a well completion system provided with an ISC well pair in an underground coal bed, and comprises the following steps:
1. the ignition method for dynamically installing the fiber laser ignition system comprises the following steps:
a. pushing the optical fiber laser head to a preset ignition position through the continuous oil pipe;
b. injecting guide carrier gas through the continuous oil pipe, and adjusting the direction of the optical fiber laser head to a preset coal bed position;
c. injecting an oxidant through the coiled tubing and the annulus passage of the injection well liner/injection well casing;
d. starting an optical fiber laser ignition system through a ground vehicle-mounted power supply to perform underground coal seam ignition;
e. after successful ignition, the equipment is retracted to a safe position;
f. injecting oxidant through the continuous oil pipe to gasify coal underground;
g. and (3) performing secondary or multiple ignition by repeating the steps a-f until all coal deposits along the direction of the lining pipe of the injection well are consumed.
In the ignition method of the dynamically installed fiber laser ignition system, an oxidant (air, oxygen-enriched air or oxygen) is preferably adopted to directly serve as a guide carrier gas of laser. Thus, the secondary/multiple ignition can be performed directly without interrupting the normal production process of underground coal gasification.
2. The ignition method of the statically installed fiber laser ignition system comprises the following steps:
a. a plurality of optical fiber laser heads are arranged at the preset coal seam ignition positions;
b. injecting guide carrier gas through the annular gap channel of the liner tube/sleeve tube and the coal seam drilling hole, and adjusting the direction of the optical fiber laser head to a preset coal seam position;
c. injecting an oxidant through the injection well liner/injection well casing internal passage;
d. starting an optical fiber laser ignition system through a ground vehicle-mounted power supply to perform underground coal seam ignition;
e. increasing the injection flow and pressure of the oxidant, and implementing underground coal gasification;
f. and (3) performing secondary or multiple ignition by repeating the steps a-e until all coal deposits along the direction of the lining pipe of the injection well are consumed.
In the ignition method of the statically installed fiber laser ignition system, nitrogen or carbon dioxide is preferably used as guide carrier gas of laser, so that coal seams beyond a preset ignition position can be prevented from being ignited in the secondary/multiple ignition process.
When the optical fiber laser ignition system and the operation method are used for implementing the underground coal gasification ignition process, the production efficiency of the whole underground coal gasification process can be improved by shortening the implementation time and improving the safety, quality and integrity of the ignition process, and meanwhile, the cost can be reduced, and the ISC project can be implemented especially in remote areas.
Embodiments of the present invention are further described below with reference to the accompanying drawings.
Fig. 1 shows a dynamically mounted fiber laser ignition system. A trolley-mounted generator or power storage device 1 provides energy to a laser source unit 2. The laser source unit 2 outputs laser light into an armored fiber optic cable string 3, the fiber optic cable string 3 containing one or more optical fibers and being connected to a fiber optic slip ring or quick connect assembly 4 mounted on a coiled tubing unit 5. Inside the coiled tubing unit 5, the optical fiber runs inside the coiled tubing 6 below the wellhead 7. In the subsurface, coiled tubing 6 is conveyed within injection well casing/liner 8. The same coiled tubing 9 is eventually run inside an injection well casing/liner in a coal seam 10 and terminates in a downhole device 11. The downhole device is shown in more detail at 12. The apparatus is used to expose a laser beam 13 to the injection well casing/liner 8 and the coal seam 10. The laser opening is protected by a spring-loaded spring cover/trapdoor 14. The laser is diverted by a reflector/mirror 15 and the laser-guided carrier gas and oxidant will force the trapdoor open through flow paths 16 or 17. The laser-guided carrier gas and oxidizer need to be activated prior to the activation of the ground vehicle unit to laser light to prevent damage to the spring cover/trapdoor 14. The laser lens 18 is used to vary the laser beam diameter and shape. At this point, the laser does not require a small focal point, it can pass through a larger focal area and a distorted pattern area to make larger openings in the casing/liner 8. The optical fiber laser head comprises a rotatable laser head main body 19 and a rotary transmission device 20, and the laser guide carrier gas and the oxidant are activated to adjust and fix the rotatable laser head main body 19 to a preset ignition position direction to start ignition. The rotation driving device 20 is shown in fig. 3, the laser guide carrier gas and the oxidant drive the gear 26 through the fan blade 25, and the laser head main body 19 performs 0-180 degree circular motion to adjust the laser emission direction. The working pressure of the pilot carrier gas/oxidant is increased to push a braking bolt 27 provided with a certain load spring 28 to fix the laser emission direction for ignition of the underground coal seam. After successful ignition, the laser ignition device is retracted to a safe position through the continuous oil pipe unit 5, and the underground coal gasification process is implemented.
Fig. 2 shows a statically mounted fibre laser ignition system with on-board units 1 and 2 identical to fig. 1. The fibre optic cable 3 is installed through the wellhead 7 during its drilling and completion process. The fiber optic cable is installed outside the casing/liner and is inserted downhole 21 into the horizontal section target area of the coal seam. The installed fiber optic cable contains a plurality of cable strings, only one of which is shown. Each cable is terminated with a simplified fiber laser head design, without rotation, and contains a pneumatic cap. The device is a consumable and is not reusable. The apparatus also does not require burning through the casing/liner and can directly ignite the target coal seam. The oxidizer/pilot carrier gas flow is used to blow off the pneumatic cap and assist in ignition. The entire statically mounted fiber laser ignition system may be pre-configured with a first ignition point 22, a second ignition point 23 and a multiple/final ignition point 24, and may have more than three ignition points.
The above-described embodiment is only a preferred embodiment of the present invention, and is not limited in any way, and other variations and modifications may be made without departing from the technical aspects set forth in the claims. Such variations and modifications are to be included within the scope of the present invention as defined in the appended claims, as may be apparent to those skilled in the art, without departing from the spirit and principles of this invention.
Claims (8)
1. A method of operating a fiber laser ignition system for an underground gasification process of coal, characterized in that the fiber laser ignition system for an underground gasification process of coal is based on an injection well liner or injection well casing as a moving channel, the fiber laser ignition system comprising the following components:
an on-board unit including a generator or power supply for providing the energy required for ignition, and a laser source for converting electrical energy into laser light;
one or more armored fiber optic cable strings for laser transmission, dynamically installed in the coiled tubing unit, and transported to the location of the desired ignition point by the coiled tubing; or statically mounted on the injection well liner/injection well casing at predetermined firing point locations, including the location of the first firing point and subsequent pre-designed firing point locations;
the optical fiber laser head is used for guiding and igniting a target coal seam by laser, and is corresponding to the optical fiber cable string, and is dynamically and directly fixed at the tail end of the oxidant conveying equipment in the continuous oil pipe unit or is statically and directly fixed at the tail end of the armored optical fiber cable string outside the liner tube/sleeve of the injection well;
the vehicle-mounted unit is connected with the optical fiber cable string through a quick connector or an optical fiber slip ring;
a well completion system based on an ISC well pair already provided in a subterranean coal seam, the method of operation being as follows:
the ignition method under the dynamic installation mode is as follows:
a. pushing the optical fiber laser head to a preset ignition position through the continuous oil pipe;
b. injecting guide carrier gas through the continuous oil pipe, and adjusting the direction of the optical fiber laser head to a preset coal bed position;
c. injecting an oxidant through the coiled tubing and the annulus passage of the injection well liner/injection well casing;
d. starting an optical fiber laser ignition system through a ground vehicle-mounted power supply to perform underground coal seam ignition;
e. after successful ignition, the equipment is retracted to a safe position;
f. injecting oxidant through the continuous oil pipe to gasify coal underground;
g. performing secondary or multiple ignition by repeating the steps a-f until all coal deposits along the direction of the lining pipe of the injection well are consumed;
the ignition method under the static installation mode is as follows:
h. a plurality of optical fiber laser heads are arranged at the preset coal seam ignition positions;
i. injecting guide carrier gas through an annular gap channel of the injection well liner tube/injection well sleeve tube and the coal seam drilling hole, and adjusting the direction of the optical fiber laser head to a preset coal seam position;
j. injecting an oxidant through the injection well liner/injection well casing internal passage;
k. starting an optical fiber laser ignition system through a ground vehicle-mounted power supply to perform underground coal seam ignition;
increasing the injection flow and pressure of the oxidant, and implementing underground coal gasification;
and m, repeating the h-l steps to perform secondary or multiple ignition until all coal deposits along the direction of the lining pipe of the injection well are consumed.
2. The method of operating a fiber laser ignition system for an underground coal gasification process according to claim 1, wherein when dynamic installation is employed, the fiber optic cable string is secured with an oxidizer delivery device within the coiled tubing unit by a quick connector, the oxidizer delivery device is connected with the fiber optic laser head by an external grapple connector or quick connector or screw threads or flange bolts with bayonet/locating bolts and provides an effective airtight seal; when static installation is adopted, the fiber cable string is directly connected with the fiber laser head through a quick connector and is fixed on the outer side of the injection well liner/injection well sleeve.
3. The method of operating a fiber laser ignition system for an underground coal gasification process of claim 1 wherein the armored fiber optic cable string comprises at least three layers of armored protective sheaths, the armored fiber optic cable string having an outer diameter of 1/8-1 inch, each fiber optic cable capable of providing 2-10kW of laser power.
4. A method of operating a fiber laser ignition system for an underground coal gasification process according to claim 3, wherein a continuous tube of a certain wall thickness is mounted on the armored fiber cable string to ensure that the fiber cable string is used in a high temperature, high pressure, pure oxygen environment.
5. The method of claim 1, wherein the fiber laser head comprises at least one reflector for diverting and adjusting the direction of laser emission, a laser lens for adjusting the diameter and area of the laser beam, and a trapdoor for protecting the fiber laser head during delivery of the fiber laser ignition system.
6. The method according to claim 1, wherein the optical fiber laser head uses air, oxygen-enriched air, oxygen, carbon dioxide or nitrogen as auxiliary guide carrier gas for laser, and the conveying channel of the guide carrier gas is the internal channel of the continuous oil pipe, the annular gap between the continuous oil pipe and the injection well liner/injection well casing and the annular gap between the injection well liner/injection well casing and the coal seam drilling.
7. The method of operating a fiber laser ignition system for an underground coal gasification process according to claim 6, wherein the fiber laser head is further provided with a rotary actuator, the fiber laser head being capable of driving the rotary actuator to produce a mechanical rotation by directing a carrier gas stream, the rotation being adjustable to impart a circular motion to a portion or the entire fiber laser head.
8. A method of operating a fiber laser ignition system for an underground coal gasification process as claimed in claim 1, based on a completion system having an ISC well pair disposed in an underground coal seam, the method of operating comprising:
in the ignition method of the dynamically installed fiber laser ignition system, an oxidant is directly used as a guide carrier gas of laser;
in the ignition method of the static installation fiber laser ignition system, nitrogen or carbon dioxide is adopted as guide carrier gas of laser.
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| US11572773B2 (en) | 2021-05-13 | 2023-02-07 | Saudi Arabian Oil Company | Electromagnetic wave hybrid tool and methods |
| US11674373B2 (en) * | 2021-05-13 | 2023-06-13 | Saudi Arabian Oil Company | Laser gravity heating |
| US11459864B1 (en) | 2021-05-13 | 2022-10-04 | Saudi Arabian Oil Company | High power laser in-situ heating and steam generation tool and methods |
| CN114609097B (en) * | 2022-03-11 | 2024-08-09 | 中国矿业大学 | System and method for evaluating heading head strength based on laser excitation spark degree |
Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6379347B1 (en) * | 1998-05-28 | 2002-04-30 | Terumo Kabushiki Kaisha | Energy irradiation apparatus |
| CA2690926A1 (en) * | 2009-01-23 | 2010-07-23 | Fiberspar Corporation | Downhole fluid separation |
| CN106121619A (en) * | 2016-08-24 | 2016-11-16 | 中为(上海)能源技术有限公司 | Ignition installation and application thereof for Underground Coal Gasification Process |
| CN106150472A (en) * | 2016-08-28 | 2016-11-23 | 中为(上海)能源技术有限公司 | Conjugation tube injected system and operational approach for coal underground gasifying technology |
| CN205990905U (en) * | 2016-08-28 | 2017-03-01 | 中为(上海)能源技术有限公司 | Conjugation tube injected system for coal underground gasifying technology |
| WO2018035734A1 (en) * | 2016-08-24 | 2018-03-01 | 中为(上海)能源技术有限公司 | Ignition device for underground coal gasification process, and applications thereof |
| WO2018035735A1 (en) * | 2016-08-24 | 2018-03-01 | 中为(上海)能源技术有限公司 | Oxidizing agent injection equipment for underground coal gasification process and application thereof |
| CN108518211A (en) * | 2018-03-29 | 2018-09-11 | 中为(上海)能源技术有限公司 | Oxidant mixed injection system and operating method for coal underground gasifying technology |
| CN208885262U (en) * | 2018-09-18 | 2019-05-21 | 中为(上海)能源技术有限公司 | Optical-fiber laser ignition system for coal underground gasifying technology |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6758844B2 (en) * | 2002-01-24 | 2004-07-06 | Ceramoptec Industries, Inc. | System and method for oral treatments |
| US6888097B2 (en) * | 2003-06-23 | 2005-05-03 | Gas Technology Institute | Fiber optics laser perforation tool |
| US20100276139A1 (en) * | 2007-03-29 | 2010-11-04 | Texyn Hydrocarbon, Llc | System and method for generation of synthesis gas from subterranean coal deposits via thermal decomposition of water by an electric torch |
| EP2795057A4 (en) * | 2011-12-21 | 2016-03-02 | Linc Energy Ltd | Underground coal gasification well liner |
| US9435184B2 (en) * | 2012-06-28 | 2016-09-06 | Carbon Energy Limited | Sacrificial liner linkages for auto-shortening an injection pipe for underground coal gasification |
| US9932803B2 (en) * | 2014-12-04 | 2018-04-03 | Saudi Arabian Oil Company | High power laser-fluid guided beam for open hole oriented fracturing |
| AU2016279806A1 (en) * | 2015-06-15 | 2017-11-16 | Halliburton Energy Services, Inc. | Igniting underground energy sources |
-
2018
- 2018-09-18 CN CN201811090784.6A patent/CN109025950B/en active Active
Patent Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6379347B1 (en) * | 1998-05-28 | 2002-04-30 | Terumo Kabushiki Kaisha | Energy irradiation apparatus |
| CA2690926A1 (en) * | 2009-01-23 | 2010-07-23 | Fiberspar Corporation | Downhole fluid separation |
| CN106121619A (en) * | 2016-08-24 | 2016-11-16 | 中为(上海)能源技术有限公司 | Ignition installation and application thereof for Underground Coal Gasification Process |
| WO2018035734A1 (en) * | 2016-08-24 | 2018-03-01 | 中为(上海)能源技术有限公司 | Ignition device for underground coal gasification process, and applications thereof |
| WO2018035735A1 (en) * | 2016-08-24 | 2018-03-01 | 中为(上海)能源技术有限公司 | Oxidizing agent injection equipment for underground coal gasification process and application thereof |
| CN106150472A (en) * | 2016-08-28 | 2016-11-23 | 中为(上海)能源技术有限公司 | Conjugation tube injected system and operational approach for coal underground gasifying technology |
| CN205990905U (en) * | 2016-08-28 | 2017-03-01 | 中为(上海)能源技术有限公司 | Conjugation tube injected system for coal underground gasifying technology |
| CN108518211A (en) * | 2018-03-29 | 2018-09-11 | 中为(上海)能源技术有限公司 | Oxidant mixed injection system and operating method for coal underground gasifying technology |
| CN208885262U (en) * | 2018-09-18 | 2019-05-21 | 中为(上海)能源技术有限公司 | Optical-fiber laser ignition system for coal underground gasifying technology |
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|---|---|
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