Composite continuous oil pipe

Abstract

The composite continuous oil pipe comprises a combustion pipe, the combustion pipe comprises a first end and a second end which are oppositely arranged, the combustion pipe is provided with a first water spraying channel, the combustion pipe is provided with a second water spraying channel in the radial direction of the combustion pipe, and the first end of the first water spraying channel communicates with the first end of the second water spraying channel; the first water path joint is arranged at the first end of the combustion pipe, is connected with the second end of the first water spraying channel and is used for introducing external cooling water; the first spray head is arranged on the peripheral side of the combustion pipe, is connected with the second end of the second water spray channel and is used for spraying radial water mist; cooling water enters the first spray head through the first water spray channel and the second water spray channel, one part of radial water mist sprayed by the first spray head is sprayed to the wall face of the sleeve, and the other part of radial water mist sprayed by the first spray head is sprayed to the peripheral side of the combustion pipe so that the sleeve and the combustion pipe can be cooled, and the sleeve and the combustion pipe can work normally in the underground high-temperature environment.

Description

Technical Field

[0001] The present application relates to the technical field of coal seam gasification mining, and in particular to a composite continuous oil pipe. Background Art

[0002] At present, underground coal seam gasification technology has basically matured, but due to the process and equipment used in the development, it has not yet formed industrialization. Underground coal gasification (UCG) is the process of burning coal in a controlled manner in situ, producing combustible gases such as H2, CO and CH4 through pyrolysis of coal and a series of chemical reactions between coal, oxygen and water vapor. UCG is also called "gasification coal mining" or "chemical coal mining." Underground gasification can fundamentally eliminate the danger of underground operations in coal mining, and output the energy contained in the coal seam to the ground in a clean manner, while the residue and waste liquid remain underground, thereby greatly reducing the pollution caused by coal mining and gas production to the environment.

[0003] In the related art, the underground gasification technology of controlling the retreat of the gas injection point refers to setting a gas injection pipe in the gasification channel, and using the gas injection pipe to continuously or intermittently retreat to achieve continuous or intermittent retreat movement of the gas injection point. In order to ensure the safety and stability of the underground coal gasification process, it is necessary to pre-embed flammable casings in the underground coal gasification material layer, and use flammable casings to control the staged combustion of the gasification material layer during the coal gasification process. The working environment temperature of the underground gasification reaction zone reaches 1000℃-1500℃, and the flammable casing is easily affected by the high temperature and burns out prematurely, causing the coal seam to collapse prematurely; in addition, although the burner head is made of high-temperature resistant alloy, the high-temperature resistant alloy will also be damaged if it is in a high-temperature environment for a long time. How to make the burner head and the embedded casing that ignites the coal seam maintain normal operation in the underground high-temperature environment and prevent it from melting and failing is a major problem that needs to be solved urgently. Summary of the invention

[0004] The present application provides a composite coiled oil pipe to solve the technical problem that the existing embedded casing and combustion head are easily affected by the high temperature environment and burn out prematurely, resulting in premature collapse of the coal seam.

[0005] The present application provides a composite coiled tubing, comprising:

[0006] A combustion tube, the combustion tube comprises a first end and a second end arranged opposite to each other, the combustion tube is provided with a first water spray channel, the combustion tube is provided with a second water spray channel along its radial direction, and the first end of the first water spray channel is connected with the first end of the second water spray channel;

[0007] A first water channel joint, disposed at the first end of the combustion tube, the first water channel joint being connected to the second end of the first water spray channel for introducing external cooling water;

[0008] A first nozzle is arranged on the outer peripheral side of the combustion tube, the first nozzle is connected to the second end of the second water spray channel, and is used for spraying radial water mist;

[0009] In one possible implementation, the second end of the combustion tube has an ignition working state. When the second end of the combustion tube is in the ignition working state, cooling water enters the first nozzle through the first water spray channel and the second water spray channel. A part of the radial water mist sprayed by the first nozzle is sprayed on the wall surface of the sleeve, and another part of the radial water mist is sprayed on the outer peripheral side of the combustion tube to cool the sleeve and the combustion tube.

[0010] In one possible implementation, a water spray control assembly is provided at the second end of the first water spray channel, and the water spray control assembly is used to control the opening and closing of the first water spray channel. When the gasification material layer where the second end of the combustion tube is located is mined, the first water spray channel is in a closed state.

[0011] In a possible implementation, a sealing portion is provided on one side of the first water channel joint close to the combustion tube, a receiving cavity is provided at the first end of the combustion tube along its axial direction, the receiving cavity is communicated with the first water spray channel, and the sealing portion is provided in the receiving cavity;

[0012] The water spray control assembly includes a sealing plug and a spring. The sealing plug is slidably arranged in the accommodating chamber. The sealing plug abuts against the sealing portion. The first end of the spring is connected to the sealing plug. The second end of the spring is connected to the wall of the accommodating chamber. A third water spray channel is arranged on the sealing plug. The third water spray channel is connected to the first water spray channel.

[0013] In a possible implementation, the sealing portion is provided with a first sealing cone surface, the sealing plug is provided with a second sealing cone surface, the first sealing cone surface abuts against the second sealing cone surface, and one end of the third water spray channel away from the first water spray channel abuts against the first sealing cone surface.

[0014] In a possible implementation, the composite coiled tubing includes a first coiled tubing, the first coiled tubing includes a first outer tube and a first inner tube, the first outer tube is sleeved on the outer circumference of the first inner tube, the inner diameter of the first outer tube is greater than the outer diameter of the first inner tube, a first annular cavity is formed between the first inner tube and the first outer tube, and the first annular cavity is connected to the first waterway joint;

[0015] The second end of the first outer tube is connected to the first end of the combustion tube. The first end of the first outer tube is provided with a water supply tray, on which a first annular water spray pipe is provided. The first annular water spray pipe is provided with a plurality of water supply holes along its circumference so that the first annular cavity is filled with cooling water.

[0016] In a possible implementation, a water inlet hole and a water return joint are provided at the first end of the combustion tube, the water inlet hole is communicated with the first annular cavity, a water return pipe is provided through the water replenishment disk, and the first end of the water return joint is connected to the water return pipe;

[0017] A cooling channel is arranged in the combustion tube, and the cooling channel is U-shaped. A first end of the cooling channel is connected to the water inlet hole, and a second end of the cooling channel is connected to the second end of the return water joint.

[0018] In a possible implementation, a combustion-supporting pipeline is provided through the water supply tray, a combustion-supporting joint is provided at the first end of the combustion tube, and the first end of the combustion-supporting pipeline passes through the first annular cavity and is connected to the first end of the combustion-supporting joint;

[0019] A combustion-supporting channel is arranged in the combustion tube, and the combustion-supporting channel is connected to the second end of the combustion-supporting joint. The combustion-supporting channel extends from one end of the combustion-supporting joint to the second end of the combustion tube. A combustion-supporting hole is arranged at the second end of the combustion tube, and the combustion-supporting hole is connected to the combustion-supporting channel.

[0020] In a possible implementation, a second waterway connector is disposed at the first end of the combustion tube, and a first end of the second waterway connector is connected to the first annular cavity;

[0021] A fourth water spray channel is arranged in the combustion tube, a second nozzle is arranged at the second end of the combustion tube, the first end of the fourth water spray channel is connected to the second end of the second water channel joint, and the second end of the fourth water spray channel is connected to the second nozzle to provide the water mist required by the underground gasification reaction zone.

[0022] In a possible implementation, an electric signal transmission connector is provided at the first end of the combustion tube, a temperature sensor and an electric ignition device are provided at the second end of the combustion tube, and the temperature sensor and the electric ignition device are electrically connected to the electric signal transmission connector via a cable;

[0023] A composite pipe cable is arranged on the water replenishment tray, and one end of the composite pipe cable passes through the first annular cavity and is connected to the electrical signal transmission connector.

[0024] In a possible implementation, the composite continuous oil pipe includes a second continuous pipe, the second continuous pipe includes a second outer pipe and a second inner pipe, the second outer pipe is sleeved on the outer peripheral side of the second inner pipe, the inner diameter of the second outer pipe is larger than the outer diameter of the second inner pipe, and a second annular cavity is formed between the second inner pipe and the second outer pipe; the second inner pipe is connected to one end of the first inner pipe away from the combustion pipe, and the second outer pipe is connected to one end of the first outer pipe away from the combustion pipe; a water supply pipe is arranged in the second annular cavity, and one end of the water supply pipe is connected to the annular water spray pipe.

[0025] In a possible implementation, a protective cover is provided at the second end of the combustion tube, and at least one through hole is provided on the protective cover.

[0026] The above technical solution provided by the embodiment of the present application has the following advantages compared with the prior art:

[0027] The composite continuous oil pipe provided in the embodiment of the present application, when the second end of the combustion tube is in the ignition working state, because the first end of the combustion tube is provided with a first water channel joint, the first water channel joint can introduce external cooling water, and the cooling water can pass through the first water spray channel and the second water spray channel in sequence, and then enter the first nozzle, and use the pressure potential energy of the groundwater to the ground and the first nozzle to atomize the water in the radial direction of the combustion tube to form radial water mist, wherein a part of the radial water mist is sprayed onto the wall of the casing, the well wall or the coal wall, which can cool the wall of the casing on the one hand, and avoid the casing from burning prematurely in a high temperature environment and causing the coal seam to collapse prematurely, and on the other hand, it can prevent the coal seam from backfired; another part of the radial water mist is sprayed onto the outer peripheral side of the combustion tube, thereby cooling the combustion tube and avoiding the combustion tube from burning and failing in a high temperature working environment. Therefore, the casing and the combustion tube can maintain normal operation in a high temperature underground environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0029] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0030] One or more embodiments are exemplarily described by pictures in the corresponding drawings, and these exemplified descriptions do not constitute limitations on the embodiments. Elements with the same reference numerals in the drawings represent similar elements, and unless otherwise stated, the figures in the drawings do not constitute proportional limitations.

[0031] Figure 1 A schematic structural diagram of a composite coiled tubing provided in one embodiment of the present application;

[0032] Figure 2 for Figure 1 A front view of the composite coiled tubing is shown;

[0033] Figure 3 For along Figure 2 View B obtained by projecting in the B direction;

[0034] Figure 4 For along Figure 2 Cross-sectional view in CC direction;

[0035] Figure 5 for Figure 4 The enlarged schematic diagram of the middle D part;

[0036] Figure 6 for Figure 1 The schematic diagram of the working state of the composite coiled tubing is shown, wherein the arrow direction shows the water flow direction or the water mist spraying direction;

[0037] Figure 7 for Figure 1 The internal structure of the composite coiled tubing is shown Figure 1 ;

[0038] Figure 8 For along Figure 2 View A obtained by projecting in the A direction;

[0039] Fig. 9 for Figure 1 The internal structure of the composite coiled tubing is shown Figure 2 ;

[0040] Fig.10 A schematic structural diagram of a first coiled tubing of a composite coiled tubing provided in another embodiment of the present application;

[0041] Fig.11 For along Fig.10 Cross-sectional view in the EE direction;

[0042] Fig.12 A schematic diagram of the structure of a composite coiled tubing provided in yet another embodiment of the present application;

[0043] Fig.13 for Fig.12 A cross-sectional view of a second coiled tubing of a composite coiled tubing is shown.

[0044] Description of reference numerals:

[0045] 1. Combustion tube; 101. First water spray channel; 102. Second water spray channel; 103. Accommodation chamber; 104. Water inlet hole; 105. Cooling channel; 106. Combustion hole; 11. Return water joint; 12. Combustion joint; 13. Second water channel joint; 14. Second nozzle; 15. Electrical signal transmission joint; 16. Temperature sensor; 17. Electric ignition device;

[0046] 2. first water channel joint; 21. sealing portion; 211. first sealing cone surface;

[0047] 3. The first nozzle;

[0048] 4. Water spray control assembly; 41. Sealing plug; 411. Third water spray channel; 412. Second sealing cone surface; 413. Groove; 42. Spring;

[0049] 5. first continuous pipe; 51. first outer pipe; 52. first inner pipe; 53. first annular cavity; 54. water supply tray; 541. annular water spray pipe; 542. water return pipe; 543. combustion-supporting pipeline; 544. composite pipe cable;

[0050] 6. second continuous tube; 61. second outer tube; 62. second inner tube; 63. second annular cavity; 64. water supply tube;

[0051] 7. Protective cover; 71. Through hole. DETAILED DESCRIPTION

[0052] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0053] The disclosure below provides many different embodiments or examples to realize the different structures of the present application. In order to simplify the disclosure of the present application, the parts and settings of specific examples are described below. Of course, they are only examples, and the purpose is not to limit the present application. In addition, the present application can repeat reference numbers and / or letters in different examples. This repetition is for the purpose of simplification and clarity, and does not itself indicate the relationship between the various embodiments and / or settings discussed.

[0054] For ease of description, spatial relative terms may be used herein to describe the relative positional relationship or movement of one element or feature relative to another element or feature as shown in the figure, such as "inside", "outside", "inner side", "outer side", "below", "below", "above", "above", "front", "back", etc. Such spatial relative terms are intended to include different orientations of the device in use or operation in addition to the orientation depicted in the figure. For example, if the device in the figure undergoes a position flip or a posture change or a motion state change, then these directional indications also change accordingly, for example: an element described as "below other elements or features" or "below other elements or features" will subsequently be oriented as "above other elements or features" or "above other elements or features". Therefore, the example term "below..." may include both upper and lower orientations. The device may be otherwise oriented (rotated 90 degrees or in other directions) and the spatial relative descriptors used herein are interpreted accordingly.

[0055] In the related art, the underground gasification technology of controlling the retreat of the gas injection point refers to setting a gas injection pipe in the gasification channel, and using the gas injection pipe to continuously or intermittently retreat to achieve continuous or intermittent retreat movement of the gas injection point. In order to ensure the safety and stability of the underground coal gasification process, it is necessary to pre-embed flammable casing in the underground coal gasification material layer, and use flammable casing to control the staged combustion of the gasification material layer during the coal gasification process. The working environment temperature of the underground gasification reaction zone reaches 1000℃-1500℃. The flammable casing is easily affected by the high temperature and burns out prematurely, causing the coal seam to collapse prematurely; in addition, although the burner head is made of high-temperature resistant alloy, the high-temperature resistant alloy will also be damaged if it is in a high-temperature environment for a long time. How to make the burner head and the embedded casing that ignites the coal seam maintain normal operation in the underground high-temperature environment and prevent it from melting and failing is a major problem that needs to be solved urgently.

[0056] In order to solve the technical problem that the existing embedded casing and combustion head are easily affected by the high temperature environment and burn out prematurely, resulting in premature collapse of the coal seam, the present application provides a composite continuous oil pipe, which can enable the casing and the combustion pipe to maintain normal operation in the underground high temperature environment, thereby improving the working reliability of the casing and the combustion pipe.

[0057] Figures 1 to 4 A composite continuous oil pipe provided in the present application includes a combustion tube 1, a first water channel joint 2 and a first nozzle 3, the combustion tube 1 includes a first end and a second end arranged opposite to each other, the combustion tube 1 is provided with a first water spray channel 101, and the combustion tube 1 is provided with a second water spray channel 102 along its radial direction, and the first end of the first water spray channel 101 is connected to the first end of the second water spray channel 102; the first water channel joint 2 is arranged at the first end of the combustion tube 1, and the first water channel joint 2 is connected to the second end of the first water spray channel 101 for introducing external cooling water; the first nozzle 3 is arranged on the outer peripheral side of the combustion tube 1, and the first nozzle 3 is connected to the second end of the second water spray channel 102 for spraying radial water mist.

[0058] It is understandable that, since the first end of the combustion tube 1 is provided with a first water channel joint 2, the first water channel joint 2 can introduce external cooling water, and the cooling water can pass through the first water spray channel 101 and the second water spray channel 102 in sequence, and then enter the first nozzle 3, and use the pressure potential energy of the groundwater to the ground and the first nozzle 3 to atomize the water in the radial direction of the combustion tube 1 to form radial water mist, wherein a part of the radial water mist is sprayed onto the wall of the casing, the well wall or the coal wall, which can cool the wall of the casing on the one hand to prevent the casing from burning prematurely in a high-temperature environment and causing the coal seam to collapse prematurely, and on the other hand to prevent the coal seam from backfired; another part of the radial water mist is sprayed onto the outer peripheral side of the combustion tube 1, thereby cooling the combustion tube 1 and preventing the combustion tube 1 from burning and failing in a high-temperature working environment. Therefore, the casing and the combustion tube 1 can maintain normal operation in a high-temperature underground environment, and the working reliability of the casing and the combustion tube 1 is improved.

[0059] The second end of the combustion tube 1 has an ignition working state. When the second end of the combustion tube 1 is in the ignition working state, cooling water enters the first nozzle 3 through the first water spray channel 101 and the second water spray channel 102. A part of the radial water mist sprayed by the first nozzle 3 is sprayed on the wall surface of the sleeve, and another part of the radial water mist is sprayed on the outer peripheral side of the combustion tube 1 to cool the sleeve and the combustion tube 1.

[0060] It should be noted that, first, a flammable casing is pre-buried in the underground coal gasification material layer, and then the combustion tube 1 is passed through the casing and lowered to the gasification reaction zone of the underground gasification material layer at the bottom of the well. During the lowering process of the combustion tube, the second end of the combustion tube is not in the ignition working state. Then, the second end of the combustion tube 1 is directed toward the gasification reaction zone, and the combustion tube 1 can separate and transport the combustion-supporting gas, oxygen and water to the gasification reaction zone. The combustion tube 1 can ignite the combustion-supporting gas, so that the coal in the gasification reaction zone is burned in situ, and combustible gases such as H2, CO and CH4 are generated through the pyrolysis of the coal and a series of chemical reactions between the coal and oxygen and water vapor. Optionally, the combustion-supporting gas may include gases such as methane and propane to help ignite the coal and start the gasification process.

[0061] For the convenience of explanation and understanding, Figure 4 As shown, the axial direction of the combustion tube 1 can be the Y direction shown in the figure, the radial direction of the combustion tube 1 can be the X direction shown in the figure, and the two sides of the axial direction of the combustion tube 1 can be respectively called the front and the rear, then, the first end of the combustion tube 1 can be called the rear end, and the second end of the combustion tube 1 can be called the front end. It can be understood that, if Figure 6 As shown, when the second end of the combustion tube 1 is in the ignition working state, since the first end of the combustion tube 1 is provided with a first water channel joint 2, the first water channel joint 2 can introduce external cooling water, and the cooling water can pass through the first water spray channel 101 and the second water spray channel 102 in sequence, and then enter the first nozzle 3, and use the pressure potential energy of the groundwater to the groundwater and the first nozzle 3 to atomize the water in the radial direction of the combustion tube 1 to form radial water mist, wherein a part of the radial water mist is sprayed onto the wall surface of the casing, the well wall or the coal wall, which can cool the wall surface of the casing on the one hand, and avoid the casing from burning prematurely in a high temperature environment and causing the coal seam to collapse prematurely, and on the other hand, it can prevent the coal seam from backfired; another part of the radial water mist is sprayed onto the outer peripheral side of the combustion tube 1, thereby cooling the combustion tube 1 and avoiding the combustion tube 1 from burning and failing in a high temperature working environment. Therefore, the casing and the combustion tube 1 can maintain normal operation in an underground high temperature environment, and improve the working reliability of the casing and the combustion tube 1.

[0062] Preferably, the first water spray channel 101 is arranged to extend along the axial direction of the combustion tube 1. That is, the first end of the first water spray channel 101 is extended and arranged close to the second end of the combustion tube 1 in the axial direction of the combustion tube 1, and is connected with the second water spray channel 102. When the cooling water flows through the first water spray channel 101, the cooling water can exchange heat with the combustion tube 1, and can also have a certain cooling effect on the combustion tube 1. The first water spray channel 101 is arranged to extend along the axial direction of the combustion tube 1, which can increase the contact area between the cooling water and the combustion tube 1 and improve the heat exchange efficiency.

[0063] After the gasification material layer in the current gasification reaction zone is mined, that is, after the coal in the current gasification reaction zone is burned out, the combustion tube 1 is controlled to move backward, and the second end of the combustion tube 1 burns the casing of the gasification reaction zone at the rear end to expose the coal wall. Then the second end of the combustion tube 1 can transport the combustion-supporting gas, oxygen and water to the gasification reaction zone at the rear end, so that the coal in the gasification reaction zone is burned in situ, and combustible gases such as H2, CO and CH4 are generated through pyrolysis of the coal and a series of chemical reactions between the coal and oxygen and water vapor, thereby realizing the staged combustion of the gasification material layer during the coal gasification process.

[0064] Exemplarily, the combustion tube 1 is made of a high temperature resistant alloy to improve the high temperature resistance of the combustion tube 1 and ensure that the combustion tube 1 can work normally in a high temperature environment. The combustion tube 1 is provided with a first hollow channel, and oxygen can be introduced into the first hollow channel. The first nozzle 3 preferably adopts an atomizing nozzle so that the sprayed water mist is dispersed more evenly, which is conducive to improving the cooling uniformity of the sleeve and the combustion tube.

[0065] In some embodiments, Figure 4 As shown, a water spray control component 4 is provided at the second end of the first water spray channel 101, and the water spray control component 4 is used to control the opening and closing of the first water spray channel 101. When the gasification material layer where the second end of the combustion tube 1 is located is mined, the first water spray channel 101 is in a closed state. It can be understood that when the gasification material layer where the second end of the combustion tube 1 is located is mined, that is, when the coal in the current gasification reaction zone is burned out, the water spray control component 4 controls the second water spray channel 102 to be in a closed state, so that the first nozzle 3 stops spraying radial water mist; then the combustion tube 1 is controlled to move backward, and the second end of the combustion tube 1 burns the casing of the gasification reaction zone at the rear end to expose the coal wall; then the second end of the combustion tube 1 can transport combustion-supporting gas, oxygen and water to the gasification reaction zone at the rear end, so that the coal in the gasification reaction zone is burned in situ to produce combustible gases such as H2, CO and CH4. At this time, the water spray control component 4 controls the first water spray channel 101 to be in an open state, so that the first nozzle 3 sprays radial water mist to cool the casing and the combustion tube 1.

[0066] In one embodiment, Figure 5 As shown, a sealing portion 21 is provided on one side of the first water channel joint 2 close to the combustion tube 1, a first end of the combustion tube 1 is provided with a receiving cavity 103 along its axial direction, the receiving cavity 103 is communicated with the first water spray channel 101, and the sealing portion 21 is provided in the receiving cavity 103; the water spray control assembly 4 includes a sealing plug 41 and a spring 42, the sealing plug 41 is slidably provided in the receiving cavity 103, the sealing plug 41 abuts against the sealing portion 21, a first end of the spring 42 is connected to the sealing plug 41, a second end of the spring 42 is connected to the wall of the receiving cavity 103, a third water spray channel 411 is provided on the sealing plug 41, and the third water spray channel 411 is communicated with the first water spray channel 101. It can be understood that when the pressure of the cooling water introduced by the first water channel joint 2 acting on the sealing plug 41 is greater than the elastic force of the spring 42, the sealing plug 41 moves away from the sealing part 21, so that the first water spray channel 101 is in an open state, and the external cooling water introduced by the first water channel joint 2 can flow into the third water spray channel 411 from the gap between the sealing part 21 and the sealing plug 41. This part of the cooling water then passes through the first water spray channel 101 and the second water spray channel 102, and then enters the first nozzle 3. The pressure potential energy of the ground to groundwater and the first nozzle 3 are used to atomize the water in the radial direction of the combustion tube 1 to form radial water mist, wherein a part of the radial water mist is sprayed onto the wall surface of the casing, the well wall or the coal wall. On the one hand, it can cool the wall surface of the casing to prevent the casing from burning prematurely in a high temperature environment and causing the coal seam to collapse prematurely, and on the other hand, it can prevent the coal seam from backfired. The other part of the radial water mist is sprayed onto the outer peripheral side of the combustion tube 1, thereby cooling the combustion tube 1 to prevent the combustion tube 1 from burning and failing in a high temperature working environment. When the pressure of the cooling water introduced by the first water channel joint 2 acting on the sealing plug 41 is less than the elastic force of the spring 42, the sealing plug 41 automatically resets under the action of the restoring force of the spring 42, that is, the sealing plug 41 moves close to the sealing portion 21 until the sealing plug 41 abuts against the sealing portion 21, and the first water spray channel 101 is in a closed state, so that the first nozzle 3 stops spraying radial water mist.

[0067] Exemplarily, the sealing portion 21 is configured as a hollow tubular body, so that the cooling water introduced by the first water channel joint 2 can flow into the inner channel of the sealing portion 21 .

[0068] In an embodiment not shown in the figure, the water spray control component 4 can also adopt the solenoid valve in the prior art. The specific structure and working principle of the solenoid valve can refer to the prior art. The solenoid valve is arranged at the second end of the first water spray channel 101 away from the second water spray channel 102, and the opening and closing of the first water spray channel 101 are controlled by controlling the opening and closing of the solenoid valve.

[0069] Optionally, an external thread is provided on the outer peripheral side of the sealing portion 21, and an internal thread matching the external thread is provided at the first end of the combustion tube 1 at the accommodating cavity 103. The sealing portion 21 is embedded in the accommodating cavity 103 and is threadedly connected to the combustion tube 1, thereby achieving a fixed connection between the sealing portion 21 and the combustion tube 1.

[0070] Alternatively, if Figure 5 As shown, a groove 413 is provided at one end of the sealing plug 41 away from the sealing portion 21, and the first end of the spring 42 is embedded in the groove 413. Such a configuration can improve the stability of compression and recovery of the spring 42, thereby improving the stability of the sealing plug 41 moving relative to the combustion tube 1, avoiding deviation between the axis of the sealing plug 41 and the axis of the sealing portion 21, thereby ensuring that the sealing plug 41 is aligned with the sealing portion 21.

[0071] In one embodiment, Figure 5 As shown, the sealing portion 21 is provided with a first sealing cone surface 211, the sealing plug 41 is provided with a second sealing cone surface 412, the first sealing cone surface 211 abuts against the second sealing cone surface 412, and the end of the third water spraying channel 411 away from the first water spraying channel 101 abuts against the first sealing cone surface 211. Specifically, the first sealing cone surface 211 is recessed toward the inside of the sealing portion 21, and the second sealing cone surface 412 is convex outwardly, so that the first sealing cone surface 211 and the second sealing cone surface 412 can better abut and cooperate, and at the same time, it can ensure that the sealing plug 41 and the sealing portion 21 are aligned, so that the external cooling water introduced by the first water channel joint 2 cannot enter the third water spraying channel 411, and the first water spraying channel 101 is in a closed state, so that the first nozzle 3 stops spraying radial water mist.

[0072] In some embodiments, Fig.10 and Fig.11As shown, the composite coiled tubing includes a first coiled tubing 5, which includes a first outer tube 51 and a first inner tube 52. The first outer tube 51 is sleeved on the outer peripheral side of the first inner tube 52. The inner diameter of the first outer tube 51 is larger than the outer diameter of the first inner tube 52. A first annular cavity 53 is formed between the first inner tube 52 and the first outer tube 51. The first annular cavity 53 is connected to the first waterway connector 2. The second end of the first outer tube 51 is connected to the first end of the combustion tube 1. A water replenishment tray 54 is provided at the first end of the first outer tube 51. A first annular water spraying pipe 541 is provided on the water replenishment tray 54. The first annular water spraying pipe 541 is provided with a plurality of water replenishment holes along its circumference to fill the first annular cavity 53 with cooling water. Since the first coiled tubing 5 is close to the gasification reaction zone, the first coiled tubing 5 is also in a high temperature environment. The first coiled tubing 5 also needs to be cooled to ensure the working reliability of the first coiled tubing 5. It can be understood that the first annular water spray pipe 541 is provided with a plurality of water supply holes along its circumference. The plurality of water supply holes can be evenly arranged in a ring shape in the circumference of the first reversing water spray pipe, and can also be arranged at intervals along the axial direction of the first reversing water spray pipe, so that the first annular cavity 53 is filled with cooling water, and heat exchange occurs between the cooling water and the tube wall of the first continuous tube 5. The cooling water absorbs the heat of the combustion tube 1, thereby cooling the first continuous tube 5.

[0073] Specifically, the first water channel joint 2 is provided with a second hollow channel, and the second hollow channel is connected to the first annular cavity 53 to introduce cooling water into the first annular cavity 53. The pressure on the sealing plug 41 is regulated by controlling the water pressure of the cooling water in the first annular cavity 53, thereby controlling the opening and closing of the first water spray channel 101, and further controlling the radial water mist of the first nozzle 3 to achieve cooling of the sleeve and the combustion tube 1.

[0074] It should be noted that the first inner tube 52 is used to transport oxygen, and one end of the first inner tube 52 can extend into the first hollow channel of the combustion tube 1 to transport oxygen to the gasification reaction zone.

[0075] In one embodiment, Figure 7 and Fig.11As shown, a water inlet hole 104 and a water return joint 11 are provided at the first end of the combustion tube 1, the water inlet hole 104 is communicated with the first annular cavity 53, a water return pipe 542 is penetrated through the water replenishment disk 54, and the first end of the water return joint 11 is connected to the water return pipe 542; a cooling channel 105 is provided in the combustion tube 1, and the cooling channel 105 is U-shaped, the first end of the cooling channel 105 is connected to the water inlet hole 104, and the second end of the cooling channel 105 is connected to the second end of the water return joint 11. It can be understood that the water inlet 104 is connected to the first annular cavity 53, and external cooling water can enter the cooling channel 105 from the water inlet 104. The cooling water exchanges heat with the combustion tube 1, and the cooling water absorbs the heat of the combustion tube 1, thereby cooling the combustion tube 1; then the return pipe 542 transports the hot water to the external cooling system on the ground, and the external cooling system continuously transports cooling water to the first annular cavity 53, so that the combustion tube 1 can be effectively cooled, thereby avoiding the combustion tube 1 from burning and failing in a high-temperature working environment, and further improving the working reliability of the combustion tube 1.

[0076] It should be noted that there can be multiple water inlet holes 104, multiple cooling channels 105, and multiple water inlet holes 104 and cooling channels 105 correspond to each other; there can be multiple return pipes 542, multiple cooling channels 105, and multiple return pipes 542 and cooling channels 105 are connected to each other in a one-to-one manner, thereby increasing the contact area between the cooling water and the combustion tube 1 and improving the cooling efficiency. The second section of the combustion tube 1 can be provided with a plug to ensure the sealing of the cooling channel 105.

[0077] In one embodiment, Figure 3 and Fig.11 As shown, a combustion-supporting pipeline 543 is provided through the water replenishment tray 54, a combustion-supporting joint 12 is provided at the first end of the combustion tube 1, and the first end of the combustion-supporting pipeline 543 passes through the first annular cavity 53 and is connected to the first end of the combustion-supporting joint 12; a combustion-supporting channel is provided in the combustion tube 1, and the combustion-supporting channel is connected to the second end of the combustion-supporting joint 12, and the end of the combustion-supporting channel away from the combustion-supporting joint 12 extends to the second end of the combustion tube 1, and a combustion-supporting hole 106 is provided at the second end of the combustion tube 1, and the combustion-supporting hole 106 is connected to the combustion-supporting channel. It can be understood that the combustion-supporting pipeline 543 can transport the combustion-supporting gas to the combustion-supporting channel, and the combustion-supporting gas flows out of the combustion-supporting hole 106 and burns with oxygen to assist in igniting the coal in the gasification reaction zone, so that the coal in the gasification reaction zone is burned in situ, and combustible gases such as H2, CO and CH4 are generated through the pyrolysis of the coal and a series of chemical reactions between the coal and oxygen and water vapor.

[0078] In one embodiment, Figure 8As shown, the first end of the combustion tube 1 is provided with a second water channel joint 13, and the first end of the second water channel joint 13 is connected to the first annular cavity 53; the combustion tube 1 is provided with a fourth water spray channel along its axial direction, and the second end of the combustion tube 1 is provided with a second nozzle 14, and the first end of the fourth water spray channel is connected to the second end of the second water channel joint 13, and the second end of the fourth water spray channel is connected to the second nozzle 14, so as to provide the water mist required by the underground gasification reaction zone. It can be understood that, as Figure 6 As shown, the second water channel joint 13 can introduce the water of the first annular cavity 53 into the fourth water spray channel, so that the second nozzle 14 sprays axial water mist toward the gasification reaction zone of the underground gasification layer. The axial water mist is mixed with oxygen underground as a gasifying agent and sprayed into the gasification reaction zone. With the combustion of coal, combustible gases such as H2, CO and CH4 are generated through the pyrolysis of coal and a series of chemical reactions between coal and the gasifying agent.

[0079] The second nozzle 14 is preferably an atomizing nozzle, so that the sprayed water mist is dispersed more evenly, which is beneficial to the gasification reaction of the underground gasification material layer.

[0080] In one embodiment, Figure 3 and Figure 8 As shown, the first end of the combustion tube 1 is provided with an electric signal transmission connector 15, and the second end of the combustion tube 1 is provided with a temperature sensor 16 and an electric ignition device 17 (spark plug), and the temperature sensor 16 and the electric ignition device 17 are electrically connected to the electric signal transmission connector 15 via a cable; a composite pipe cable 544 is provided on the water replenishment tray 54, and one end of the composite pipe cable 544 passes through the first annular cavity 53 and is connected to the electric signal transmission connector 15 to realize the transmission of electric signals such as ignition signals and temperature signals. It should be noted that the electric ignition device 17 can adopt the spark plug in the prior art, and the electric ignition device 17 can ignite the combustion-supporting gas; the temperature sensor 16 can adopt the thermocouple in the prior art, and the temperature sensor 16 can detect the temperature of the environment in which the combustion tube 1 is located. As shown Fig. 9 As shown, multiple cables can be arranged inside the composite pipe and cable 544, thereby realizing the integration of the composite pipe and cable 544.

[0081] In this embodiment, a flammable casing is first pre-buried in the underground coal gasification layer, and then the burner head is passed through the casing and probed into the gasification reaction zone of the underground gasification layer at the bottom of the well. The second end of the combustion tube 1 faces the gasification reaction zone. The combustion tube 1 can separate the combustion-supporting gas, oxygen and water and transport them to the gasification reaction zone. The electric ignition device 17 can ignite the combustion-supporting gas. The temperature sensor 16 can detect the temperature of the environment in which the combustion tube 1 is located in real time. The position of the composite coiled tubing is appropriately adjusted according to the temperature at the bottom of the well and the composition of the outlet coal gas to achieve continuous backward gasification.

[0082] In an embodiment not shown in the figure, the composite pipe-cable 544 includes a protective tube and a cable. A filling layer is provided in the internal space of the protective tube, and the filling layer can provide insulation, flame retardancy, corrosion resistance, fixation and other protective functions for the coated cable. Furthermore, one or more layers of steel wire armor are provided on the outside of the protective tube, and the steel wire armor can improve the tensile strength of the protective tube. Specifically, the steel wire armor includes a plurality of protective ribs made of steel wire, which can be arranged along the axis of the protective tube and coated on the outer peripheral side of the protective tube; the protective ribs can also be arranged in a spiral shape, and the spiral protective ribs are spirally arranged on the outer peripheral side of the protective tube. The protective ribs not only increase the overall strength and tensile strength of the protective tube, but also effectively prevent external impact forces from directly acting on the protective tube during the transportation of the composite pipe-cable 544, thereby improving the protective ability of the composite pipe-cable 544.

[0083] In some embodiments, Fig.12 and Fig.13 As shown, the composite coiled tubing includes a second coiled tubing 6, which includes a second outer tube 61 and a second inner tube 62. The second outer tube 61 is sleeved on the outer peripheral side of the second inner tube 62. The inner diameter of the second outer tube 61 is larger than the outer diameter of the second inner tube 62. A second annular cavity 63 is formed between the second inner tube 62 and the second outer tube 61. The second inner tube 62 is connected to an end of the first inner tube 52 away from the combustion tube 1, and the second outer tube 61 is connected to an end of the first outer tube 51 away from the combustion tube 1. A water supply pipe 64 is arranged in the second annular cavity 63. The first end of the water supply pipe 64 is connected to a ground cooling water system (such as a water pump), and the second end of the water supply pipe 64 is extended along the axial direction of the second inner tube 62 and connected to the annular water spray pipe. The water pump can continuously supply cooling water to the water supply pipe 64, so that the first coiled tubing 5, the combustion tube 1 and the casing can be effectively cooled.

[0084] It should be noted that the first inner tube 52 and the second inner tube 62 can be connected by laser welding or argon arc welding, and the first outer tube 51 and the second outer tube 61 can also be connected by laser welding or argon arc welding. The aforementioned composite pipe cable 544, the combustion-supporting pipeline 543, the return pipe 542 and the water supply pipe 64 can be towed into the second annular cavity 63 using a traction device. For example, the composite pipe cable 544, the combustion-supporting pipeline 543, the return pipe 542 and the water supply pipe 64 are bundled and connected with a wire rope, and the wire rope is towed using a traction device to insert the composite pipe cable 544, the combustion-supporting pipeline 543, the return pipe 542 and the water supply pipe 64 into the second annular cavity 63. The second continuous pipe 6 can be a straight pipe, a curved pipe, or a plurality of pipe sections welded in sequence. Since the underground gasification channel is long, a modular design of assembling multiple continuous pipes is adopted to facilitate later replacement.

[0085] Of course, there can be multiple water supply pipes 64 and multiple annular water spray pipes, and the multiple water supply pipes 64 are connected to the annular water spray pipes in a one-to-one correspondence.

[0086] In some embodiments, Fig.12 As shown, the second end of the combustion tube 1 is provided with a protective cover 7, and at least one through hole 71 is provided on the protective cover 7. In the process of the combustion tube 1 descending to the bottom of the well, the protective cover 7 can protect the electric ignition device 17, the temperature sensor 16 and the second nozzle 14 installed at the front end of the combustion tube 1 to avoid damage caused by external forces. The working process of this embodiment is that firstly, a flammable casing is pre-buried in the underground coal gasification material layer, and then the combustion tube 1 passes through the casing and descends to the gasification reaction zone of the underground gasification material layer at the bottom of the well, and the second end of the combustion tube 1 faces the gasification reaction zone, and the combustion-supporting gas is injected into the bottom of the well after passing through the through hole 71 of the protective cover 7, and the electric ignition device 17 ignites the combustion-supporting gas, and the gas combustion generates high temperature. When the ambient temperature reaches 1000°C, the protective cover 7 is burned; then, the second nozzle 14 sprays axial water mist, so that the coal in the gasification reaction zone is burned in situ to produce combustible gases such as H2, CO and CH4.

[0087] It should be understood that the terms used herein are only for the purpose of describing specific example embodiments and are not intended to be limiting. Unless the context clearly indicates otherwise, the singular forms "one", "an" and "said" as used herein may also be meant to include plural forms. The terms "include", "comprise", "contain", and "have" are inclusive and therefore specify the existence of stated features, steps, operations, elements and / or parts, but do not exclude the existence or addition of one or more other features, steps, operations, elements, parts, and / or combinations thereof. The method steps, processes, and operations described herein are not interpreted as necessarily requiring them to be performed in the specific order described or illustrated, unless the execution order is clearly indicated. It should also be understood that additional or alternative steps may be used.

[0088] Although the terms first, second, third, etc. can be used in the text to describe multiple elements, components, regions, layers and / or sections, these elements, components, regions, layers and / or sections should not be limited by these terms. These terms can only be used to distinguish an element, component, region, layer or section from another region, layer or section. Unless the context clearly indicates, terms such as "first", "second" and other numerical terms do not imply order or sequence when used in the text. Therefore, the first element, component, region, layer or section discussed below can be referred to as the second element, component, region, layer or section without departing from the teaching of the example embodiments.

[0089] The above description is only a specific implementation of the present application, so that those skilled in the art can understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest range consistent with the principles and novel features applied for herein.

Claims

1. A composite coiled tubing, characterized in that: include: A combustion tube, the combustion tube comprising a first end and a second end arranged opposite to each other, the combustion tube being provided with a first water spray channel, the combustion tube being provided with a second water spray channel along a radial direction thereof, the first end of the first water spray channel being in communication with the first end of the second water spray channel; a first water channel joint, disposed at the first end of the combustion tube, the first water channel joint being connected to the second end of the first water spray channel for introducing external cooling water; The first nozzle is arranged on the outer peripheral side of the combustion tube, and the first nozzle is connected to the second end of the second water spray channel, and is used for spraying radial water mist.

2. The composite coiled tubing according to claim 1, characterized in that: The second end of the combustion tube has an ignition working state. When the second end of the combustion tube is in the ignition working state, the cooling water enters the first nozzle through the first water spray channel and the second water spray channel. A part of the radial water mist sprayed by the first nozzle is sprayed on the wall surface of the sleeve, and another part of the radial water mist is sprayed on the outer peripheral side of the combustion tube to cool the sleeve and the combustion tube.

3. The composite coiled tubing according to claim 1 or 2, characterized in that: A water spray control component is provided at the second end of the first water spray channel, and the water spray control component is used to control the opening and closing of the first water spray channel. When the gasification material layer where the second end of the combustion tube is located is mined, the first water spray channel is in a closed state.

4. The composite coiled tubing according to claim 3, characterized in that: A sealing portion is provided on one side of the first water channel joint close to the combustion tube, a receiving cavity is provided along the axial direction of the first end of the combustion tube, the receiving cavity is communicated with the first water spray channel, and the sealing portion is provided in the receiving cavity; The water spray control assembly includes a sealing plug and a spring, the sealing plug is slidably disposed in the accommodating chamber, the sealing plug abuts against the sealing portion, the first end of the spring is connected to the sealing plug, the second end of the spring is connected to the wall of the accommodating chamber, and a third water spray channel is disposed on the sealing plug, and the third water spray channel is connected to the first water spray channel.

5. The composite coiled tubing according to claim 4, characterized in that: The sealing portion is provided with a first sealing cone surface, the sealing plug is provided with a second sealing cone surface, the first sealing cone surface abuts against the second sealing cone surface, and one end of the third water spray channel away from the first water spray channel abuts against the first sealing cone surface.

6. The composite coiled tubing according to claim 4, characterized in that: The composite coiled tubing includes a first coiled tubing, the first coiled tubing includes a first outer tube and a first inner tube, the first outer tube is sleeved on the outer circumference of the first inner tube, the inner diameter of the first outer tube is greater than the outer diameter of the first inner tube, a first annular cavity is formed between the first inner tube and the first outer tube, and the first annular cavity is connected to the first waterway joint; The second end of the first outer tube is connected to the first end of the combustion tube, and a water replenishment tray is provided at the first end of the first outer tube. A first annular water spray pipe is provided on the water replenishment tray, and a plurality of water replenishment holes are provided along the circumference of the first annular water spray pipe so that the first annular cavity is filled with the cooling water.

7. The composite coiled tubing according to claim 6, characterized in that: The first end of the combustion tube is provided with a water inlet hole and a water return joint, the water inlet hole is communicated with the first annular cavity, a water return pipe is penetrated through the water replenishment tray, and the first end of the water return joint is connected to the water return pipe; A cooling channel is arranged in the combustion tube, and the cooling channel is U-shaped. A first end of the cooling channel is connected to the water inlet, and a second end of the cooling channel is connected to the second end of the water return joint.

8. The composite coiled tubing according to claim 6, characterized in that: A combustion-supporting pipeline is provided through the water replenishment tray, a combustion-supporting joint is provided at the first end of the combustion tube, the first end of the combustion-supporting pipeline passes through the first annular cavity and is connected to the first end of the combustion-supporting joint; A combustion-supporting channel is arranged in the combustion tube, and the combustion-supporting channel is connected to the second end of the combustion-supporting joint. The combustion-supporting channel extends from one end of the combustion-supporting joint to the second end of the combustion tube. A combustion-supporting hole is arranged at the second end of the combustion tube, and the combustion-supporting hole is connected to the combustion-supporting channel.

9. The composite coiled tubing according to claim 6, characterized in that: A second waterway connector is disposed at the first end of the combustion tube, and a first end of the second waterway connector is connected to the first annular cavity; A fourth water spray channel is arranged in the combustion tube, a second nozzle is arranged at the second end of the combustion tube, a first end of the fourth water spray channel is connected to the second end of the second water channel joint, and a second end of the fourth water spray channel is connected to the second nozzle to provide water mist required for the underground gasification reaction zone.

10. The composite coiled tubing according to claim 6, characterized in that: The first end of the combustion tube is provided with an electric signal transmission connector, the second end of the combustion tube is provided with a temperature sensor and an electric ignition device, and the temperature sensor and the electric ignition device are electrically connected to the electric signal transmission connector through a cable; A composite pipe cable is arranged on the water replenishment tray, and one end of the composite pipe cable passes through the first annular cavity and is connected to the electrical signal transmission connector.

11. The composite coiled tubing according to claim 6, characterized in that: The composite coiled tubing includes a second coiled tubing, which includes a second outer tube and a second inner tube. The second outer tube is sleeved on the outer circumference of the second inner tube, the inner diameter of the second outer tube is greater than the outer diameter of the second inner tube, and a second annular cavity is formed between the second inner tube and the second outer tube. The second inner tube is connected to one end of the first inner tube away from the combustion tube, and the second outer tube is connected to one end of the first outer tube away from the combustion tube. A water supply pipe is arranged in the second annular cavity, and one end of the water supply pipe is connected to an annular water spraying pipe.

12. The composite coiled tubing according to any one of claims 1 to 11, characterized in that: The second end of the combustion tube is provided with a protective cover, and the protective cover is provided with at least one through hole.

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