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 particularly relates to a composite coiled tubing. BACKGROUND

[0002] At present, the coal seam underground gasification technology has been basically mature, but the process and equipment used for mining have not been industrialized. Underground coal gasification (UCG) is a process of controlled combustion of coal in situ, through pyrolysis of coal and a series of chemical reactions of coal with oxygen and water vapor to produce H2, CO and CH4 combustible gases. UCG is also known as "gasification coal mining" or "chemical coal mining". Underground gasification can fundamentally eliminate the underground operation danger of coal mining, output the energy contained in the coal seam to the ground in a clean and complete manner, and leave the residue and waste liquid underground, thereby greatly reducing the pollution caused by coal mining and gas production to the environment.

[0003] In the related art, the control-receding gas injection point underground gasification technology refers to setting a gas injection pipe in a gasification channel, and continuously or intermittently retreating the gas injection pipe to realize continuous or intermittent rearward movement of the gas injection point. In order to ensure the safety and stability of the underground coal gasification process, a combustible sleeve is pre-buried in the coal seam of the underground coal gasification layer, and the combustible sleeve is used to control the staged combustion of the gasification layer in the coal gasification process. The working environment temperature of the underground gasification reaction zone reaches 1000-1500 DEG C, and the combustible sleeve is easily affected by high temperature and burned out in advance, resulting in premature collapse of the coal seam. In addition, although the combustion head is made of high-temperature alloy, the high-temperature alloy will also be damaged after a long time in a high-temperature environment. How to make the combustion head and the pre-buried sleeve that ignite the coal seam maintain normal work in the underground high-temperature environment and prevent them from melting and failing is a big problem to be solved. CONTENT OF THE UTILITY MODEL

[0004] The present application provides a composite coiled tubing to solve the technical problem that the existing pre-buried sleeve and combustion head are easily affected by high-temperature environment and burned out in advance, resulting in premature collapse of the coal seam.

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

[0006] The combustion pipe comprises a first end and a second end arranged oppositely, and the combustion pipe is provided with a first water injection channel, and the combustion pipe is provided with a second water injection channel along the radial direction thereof, and the first end of the first water injection channel is in communication with the first end of the second water injection channel;

[0007] The first waterway joint is arranged at the first end of the combustion pipe, and the first waterway joint is connected with the second end of the first water injection channel and used for introducing external cooling water;

[0008] The first nozzle is arranged at the outer circumferential side of the combustion pipe, and the first nozzle is connected with the second end of the second water injection channel and used for spraying radial water mist;

[0009] In a possible implementation, the second end of the combustion pipe has an ignition working state, when the second end of the combustion pipe is in the ignition working state, the cooling water enters the first spray head through the first water spray channel and the second water spray channel, and part of the radial water mist sprayed by the first spray head sprays on the wall surface of the sleeve pipe, and the other part sprays on the outer circumferential side of the combustion pipe to cool the sleeve pipe and the combustion pipe.

[0010] In a possible implementation, the second end of the first water spray channel is provided with a water spray control assembly for controlling the opening and closing of the first water spray channel, and when the second end of the combustion pipe is in the gasified layer mining completion state, the first water spray channel is in a closed state.

[0011] In a possible implementation, the first waterway joint is provided with a sealing part near one side of the combustion pipe, the first end of the combustion pipe is provided with a receiving cavity along the axial direction thereof, the receiving cavity is in communication with the first water spray channel, and the sealing part is arranged in the receiving cavity.

[0012] The water spray control assembly comprises a sealing plug and a spring, the sealing plug is slidingly arranged in the receiving cavity, the sealing plug is in abutment with the sealing part, the first end of the spring is connected with the sealing plug, the second end of the spring is connected with the wall surface of the receiving cavity, the sealing plug is provided with a third water spray channel, and the third water spray channel is in communication with the first water spray channel.

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

[0014] In a possible implementation, the composite coiled tubing comprises a first coiled pipe, the first coiled pipe comprises a first outer pipe and a first inner pipe, the first outer pipe is sleeved on the outer circumferential side of the first inner pipe, the inner diameter of the first outer pipe is larger than the outer diameter of the first inner pipe, a first annular cavity is formed between the first inner pipe and the first outer pipe, and the first annular cavity is connected with the first waterway joint.

[0015] The second end of the first outer pipe is connected with the first end of the combustion pipe, the first end of the first outer pipe is provided with a water supplement disc, the water supplement disc is provided with a first annular water spray pipe, the first annular water spray pipe is provided with a plurality of water supplement holes in the circumferential direction thereof, and the first annular cavity is filled with cooling water.

[0016] In a possible implementation, the first end of the combustion pipe is provided with a water inlet hole and a water return joint, the water inlet hole is in communication with the first annular cavity, a water return pipe is penetratingly arranged on the water supplement disc, and the first end of the water return joint is connected with the water return pipe.

[0017] The combustion pipe is provided with a cooling channel, the cooling channel is in a U shape, a first end of the cooling channel is connected with the water inlet hole, and a second end of the cooling channel is connected with a second end of the water return joint.

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

[0019] The combustion pipe is provided with a combustion supporting channel, a second end of the combustion supporting channel is connected with the combustion supporting joint, an end of the combustion supporting channel, which is away from the combustion supporting joint, extends and is arranged towards the second end of the combustion pipe, and the second end of the combustion pipe is provided with a combustion supporting hole connected with the combustion supporting channel.

[0020] In a possible implementation, a second waterway joint is arranged at the first end of the combustion pipe, and a first end of the second waterway joint is connected with the first annular cavity.

[0021] The combustion pipe is provided with a fourth water spraying channel, the second end of the combustion pipe is provided with a second spraying head, a first end of the fourth water spraying channel is connected with a second end of the second waterway joint, and a second end of the fourth water spraying channel is connected with the second spraying head, so as to provide the water mist required by the underground gasification reaction zone.

[0022] In a possible implementation, an electric signal transmission joint is arranged at the first end of the combustion pipe, a temperature measuring sensor and an electric ignition device are arranged at the second end of the combustion pipe, and the temperature measuring sensor and the electric ignition device are electrically connected with the electric signal transmission joint through a cable.

[0023] The water supply tray is provided with a composite pipe cable, one end of the composite pipe cable passes through the first annular cavity and is connected with the electric signal transmission joint.

[0024] In a possible implementation, the composite coiled tubing comprises a second coiled pipe, the second coiled pipe comprises a second outer pipe and a second inner pipe, the second outer pipe is sleeved on the outer circumferential side of the second inner pipe, the inner diameter of the second outer pipe is greater 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; one end of the second inner pipe is connected with one end of the first inner pipe, which is away from the combustion pipe, and one end of the second outer pipe is connected with one end of the first outer pipe, which is away from the combustion pipe; and a water supply pipe is arranged in the second annular cavity, and one end of the water supply pipe is connected with the annular water spraying pipe.

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

[0026] Compared with the prior art, the above technical solutions provided by the embodiments of the present application have the following advantages:

[0027] The composite continuous tubing provided in this application embodiment, when the second end of the combustion tube is in the ignition working state, has a first water connector at the first end of the combustion tube. This first water connector allows external cooling water to be introduced, which then passes through a first and a second water spray channel before entering a first nozzle. Utilizing the pressure potential energy of the groundwater and the first nozzle, the water is atomized radially in the combustion tube, forming radial water mist. A portion of this radial water mist is sprayed onto the casing wall, well wall, or coal seam. This cools the casing wall, preventing premature burn-out and coal seam collapse under high temperatures, and also prevents backfire. Another portion of the radial water mist is sprayed onto the outer periphery of the combustion tube, further cooling it and preventing burn-out and failure under high-temperature conditions. Therefore, the casing and combustion tube can maintain normal operation in high-temperature underground environments. Attached Figure Description

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

[0029] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0030] One or more embodiments are illustrated by way of example with reference numerals in the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Elements with the same reference numerals in the drawings are denoted as similar elements. Unless otherwise stated, the figures in the drawings are not to be limited by scale.

[0031] Figure 1 This is a schematic diagram of the structure of a composite coiled tubing provided in one embodiment of this application;

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

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

[0034] Figure 4 For along Figure 3 A cross-sectional view along the CC direction;

[0035] Figure 5 for Figure 4 Enlarged schematic diagram of section D in the middle;

[0036] Figure 6 for Figure 1 The diagram shows the working state of the composite coiled tubing, where the arrows indicate the direction of water flow or water mist spray.

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

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

[0039] Figure 9 for Figure 1 Schematic diagram of the internal structure of the composite coiled tubing shown Figure 2 ;

[0040] Figure 10 This is a schematic diagram of the structure of the first continuous tube of a composite continuous tubing provided in another embodiment of this application;

[0041] Figure 11 For along Figure 10 A cross-sectional view along the EE direction;

[0042] Figure 12 A schematic diagram of the structure of a composite coiled tubing provided in another embodiment of this application;

[0043] Figure 13 for Figure 12 The diagram shows a cross-sectional view of the second continuous tube in the composite continuous tubing system.

[0044] Explanation of reference numerals in the attached figures:

[0045] 1. Combustion tube; 101. First water spray channel; 102. Second water spray channel; 103. Receptacle; 104. Water inlet; 105. Cooling channel; 106. Combustion port; 11. Water return connector; 12. Combustion connector; 13. Second water circuit connector; 14. Second nozzle; 15. Electrical signal transmission connector; 16. Temperature sensor; 17. Electric ignition device;

[0046] 2. First water passage connector; 21. Sealing part; 211. First sealing cone surface;

[0047] 3. 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 tube; 51. first outer tube; 52. first inner tube; 53. first annular cavity; 54. water supply tray; 541. annular water jet pipe; 542. water return pipe; 543. combustion supporting pipe; 544. composite pipe cable;

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

[0051] 7. protective cover; 71. through hole. DETAILED DESCRIPTION

[0052] In order to make the objects, technical solutions, and advantages of the embodiments of the present application clearer, the following will be used in conjunction with the accompanying drawings for the embodiments of the present application to make a clear and complete description of the technical solutions in the embodiments of the present application. Obviously, the described embodiments are some but not all of the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0053] The following disclosure provides many different embodiments, or examples, for implementing different structures of the present application. For the purpose of simplicity, the description of a particular example will not necessarily be repeated in the description of each example. Of course, they are merely examples and are not intended to limit the present application. In addition, reference numerals and / or letters can be repeated in different examples in the present application. Such repetition is for the purpose of simplicity and clarity and does not indicate a relationship between the various embodiments and / or arrangements being discussed.

[0054] For the purpose of description, spatial relative terms used in the description, such as "inner", "outer", "inward", "outward", "lower", "below", "upper", "above", "front", "back", etc., can be used to describe the relative position relationship or movement of one element or feature with respect to another element or feature as shown in the drawings. 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 drawings. For example, if the device in the drawings is turned over or the posture is changed or the movement state is changed, the directional indications will also change accordingly, for example: the element described as "below" or "under" another element or feature will be subsequently oriented as "above" or "over" the other element or feature. Therefore, the example term "below" can include both upward and downward positions. The device can be additionally oriented (rotated by 90 degrees or in other directions) and the spatial relative relationship descriptors used in the description are interpreted accordingly.

[0055] In the related art, the control of the retreating gas injection point underground gasification technology refers to setting a gas injection pipe in the gasification passage, and continuously or intermittently retreating the gas injection pipe to realize the continuous or intermittent retreat of the gas injection point. In order to ensure the safety and stability of the underground coal gasification process, it is necessary to pre-bury a combustible sleeve in the coal underground gasification layer, and use the combustible sleeve to control the staged combustion of the gasification layer in the coal gasification process. The working environment temperature of the underground gasification reaction zone reaches 1000-1500 DEG C, and the combustible sleeve is easily affected by high temperature and burned out in advance, resulting in the advance collapse of the coal seam. In addition, although the combustion head is made of high-temperature alloy, the high-temperature alloy will also be damaged in a long time in a high-temperature environment. How to make the combustion head and the pre-buried sleeve that ignite the coal seam keep normal work in the underground high-temperature environment and prevent them from melting failure is a big problem to be solved.

[0056] In order to solve the technical problems that the existing pre-buried sleeve and combustion head are easily affected by high temperature and burned out in advance, resulting in the advance collapse of the coal seam, the application provides a composite coiled tubing, which can make the sleeve and the combustion pipe keep normal work in the underground high-temperature environment and improve the working reliability of the sleeve and the combustion pipe.

[0057] Figures 1 to 4 The composite coiled tubing provided by the application comprises a combustion pipe 1, a first waterway joint 2 and a first nozzle 3. The combustion pipe 1 comprises a first end and a second end arranged oppositely. The combustion pipe 1 is provided with a first water injection channel 101. The combustion pipe 1 is provided with a second water injection channel 102 along the radial direction thereof. The first end of the first water injection channel 101 is communicated with the first end of the second water injection channel 102. The first waterway joint 2 is arranged at the first end of the combustion pipe 1. The first waterway joint 2 is connected with the second end of the first water injection channel 101 and used for introducing external cooling water. The first nozzle 3 is arranged at the outer circumferential side of the combustion pipe 1. The first nozzle 3 is connected with the second end of the second water injection channel 102 and used for spraying radial water mist.

[0058] It can be understood that, since the first end of the combustion pipe 1 is provided with the first waterway joint 2, the first waterway joint 2 can introduce external cooling water. The cooling water can pass through the first water injection channel 101 and the second water injection channel 102 in turn and then enter the first nozzle 3. The water is atomized in the radial direction of the combustion pipe 1 by using the pressure potential energy from the ground to the underground water and the first nozzle 3, to form radial water mist. Part of the radial water mist is sprayed to the wall surface of the sleeve, the well wall or the coal wall. On the one hand, the wall surface of the sleeve can be cooled to avoid the sleeve from being burned out in advance in the high-temperature environment and causing the advance collapse of the coal seam. On the other hand, the coal seam can be prevented from backfire combustion. The other part of the radial water mist is sprayed to the outer circumferential side of the combustion pipe 1, so as to cool the combustion pipe 1 and avoid the combustion pipe 1 from being burned out and failed in the high-temperature working environment. Therefore, the sleeve and the combustion pipe 1 can keep normal work in the underground high-temperature environment, and the working reliability of the sleeve and the combustion pipe 1 is improved.

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

[0060] It should be noted that the combustible sleeve pipe is first embedded in the coal underground gasification layer, and then the combustion pipe 1 passes through the sleeve pipe and is lowered to the gasification reaction zone of the underground gasification layer at the bottom of the well. During the lowering process of the combustion pipe, the second end of the combustion pipe is not in the ignition working state. Then, the second end of the combustion pipe 1 faces the gasification reaction zone, and the combustion pipe 1 can separate and deliver the combustion-supporting gas, oxygen and water to the gasification reaction zone, and the combustion pipe 1 can ignite the combustion-supporting gas, so that the coal in the gasification reaction zone is combusted in situ, and through pyrolysis of the coal and a series of chemical reactions between the coal, oxygen and water vapor, combustible gases such as H2, CO and CH4 are generated. Alternatively, the combustion-supporting gas can include methane, propane and other gases to help ignite the coal and start the gasification process.

[0061] For the convenience of description and understanding, as shown in Figure 4 , the axial direction of the combustion pipe 1 can be the Y direction shown in the figure, the radial direction of the combustion pipe 1 can be the X direction shown in the figure, and the two sides of the axial direction of the combustion pipe 1 can be respectively referred to as front and back. Then, the first end of the combustion pipe 1 can be referred to as the back end, and the second end of the combustion pipe 1 can be referred to as the front end. It can be understood that, as shown in Figure 6 , when the second end of the combustion pipe 1 is in the ignition working state, since the first waterway joint 2 is arranged at the first end of the combustion pipe 1, the first waterway joint 2 can introduce external cooling water, 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 spray head 3. By using the pressure potential energy from the ground to the underground water and the first spray head 3, the water is atomized in the radial direction of the combustion pipe 1 to form radial water mist. Part of the radial water mist is sprayed to the wall surface of the sleeve pipe, the well wall or the coal wall, which can cool the wall surface of the sleeve pipe on the one hand, and avoid the sleeve pipe from being burned out in advance in the high-temperature environment to cause the coal layer to collapse in advance, and on the other hand, can prevent the coal layer from backfire combustion. The other part of the radial water mist is sprayed to the outer peripheral side of the combustion pipe 1, so as to cool the combustion pipe 1 and avoid the combustion pipe 1 from being burned out in the high-temperature working environment. Therefore, the sleeve pipe and the combustion pipe 1 can maintain normal work in the underground high-temperature environment, and the working reliability of the sleeve pipe and the combustion pipe 1 is improved.

[0062] Preferably, the first water spraying channel 101 is arranged to extend along the axial direction of the combustion pipe 1. That is, the first end of the first water spraying channel 101 is arranged to extend close to the second end of the combustion pipe 1 in the axial direction of the combustion pipe 1 and is in communication with the second water spraying channel 102. When the cooling water flows through the first water spraying channel 101, the cooling water can exchange heat with the combustion pipe 1 and also can cool the combustion pipe 1 to a certain extent. The arrangement of the first water spraying channel 101 to extend along the axial direction of the combustion pipe 1 can increase the contact area of the cooling water with the combustion pipe 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 pipe 1 is controlled to move backward, the second end of the combustion pipe 1 burns the sleeve pipe in the gasification reaction zone at the rear end, exposes the coal wall, and then the second end of the combustion pipe 1 can deliver 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 at the rear end is burned in situ, through pyrolysis of the coal and a series of chemical reactions between the coal and oxygen and water vapor, combustible gases such as H2, CO and CH4 are generated, thereby realizing the staged combustion of the gasification material layer in the coal gasification process.

[0064] Exemplarily, the combustion pipe 1 is made of high-temperature-resistant alloy to improve the high-temperature-resistant performance of the combustion pipe 1 and ensure that the combustion pipe 1 can work normally in a high-temperature environment. The combustion pipe 1 is provided with a first hollow channel, and the first hollow channel can be connected to oxygen. The first spray head 3 preferably adopts an atomizing spray head, so that the sprayed water mist is more uniformly dispersed, which is beneficial to improving the uniformity of the cooling of the sleeve pipe and the combustion pipe.

[0065] In some embodiments, as shown in Figure 4 The second end of the first water spraying channel 101 is provided with a water spraying control assembly 4, which is used to control the opening and closing of the first water spraying channel 101. When the gasification material layer at the second end of the combustion pipe 1 is mined, that is, when the coal in the current gasification reaction zone is burned out, the first water spraying channel 101 is in a closed state. It can be understood that when the gasification material layer at the second end of the combustion pipe 1 is mined, that is, when the coal in the current gasification reaction zone is burned out, the water spraying control assembly 4 controls the second water spraying channel 102 to be in a closed state, so that the first spray head 3 stops spraying radial water mist; then the combustion pipe 1 is controlled to move backward, the second end of the combustion pipe 1 burns the sleeve pipe in the gasification reaction zone at the rear end, exposes the coal wall; then the second end of the combustion pipe 1 can deliver 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 at the rear end is burned in situ to generate combustible gases such as H2, CO and CH4, and at this time the water spraying control assembly 4 controls the first water spraying channel 101 to be in an open state, so that the first spray head 3 sprays radial water mist to cool the sleeve pipe and the combustion pipe 1.

[0066] In one embodiment, asFigure 5 As shown, the first water joint 2 is provided with a sealing part 21 near one side of the combustion pipe 1, the first end of the combustion pipe 1 is provided with a receiving cavity 103 along the axial direction thereof, the receiving cavity 103 is communicated with the first water injection channel 101, and the sealing part 21 is arranged in the receiving cavity 103; the water injection control assembly 4 comprises a sealing plug 41 and a spring 42, the sealing plug 41 is slidingly arranged in the receiving cavity 103, the sealing plug 41 abuts against the sealing part 21, the first end of the spring 42 is connected with the sealing plug 41, the second end of the spring 42 is connected with the wall surface of the receiving cavity 103, and the sealing plug 41 is provided with a third water injection channel 411, which is communicated with the first water injection channel 101. It can be understood that when the pressure of the cooling water introduced by the first water 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 injection channel 101 is in an open state, and the external cooling water introduced by the first water joint 2 can flow into the third water injection channel 411 from the gap between the sealing part 21 and the sealing plug 41, and then the cooling water passes through the first water injection channel 101 and the second water injection channel 102, and then enters the first nozzle 3, so as to atomize the water in the radial direction of the combustion pipe 1 by using the pressure potential energy from the ground to the underground water and the first nozzle 3, and form radial water mist, part of which is sprayed to the wall surface of the casing pipe, the well wall or the coal wall, which can cool the wall surface of the casing pipe, avoid the casing pipe from being burned out in advance due to high temperature environment, and cause the coal seam to collapse in advance, and prevent the coal seam from burning back; the other part of the radial water mist is sprayed to the outer circumferential side of the combustion pipe 1, so as to cool the combustion pipe 1 and avoid the combustion pipe 1 from being burned out due to high temperature working environment. When the pressure of the cooling water introduced by the first water joint 2 acting on the sealing plug 41 is less than the elastic force of the spring 42, the sealing plug 41 is automatically reset under the restoring force of the spring 42, that is, the sealing plug 41 moves close to the sealing part 21 until the sealing plug 41 abuts against the sealing part 21, and the first water injection channel 101 is in a closed state, so that the first nozzle 3 stops spraying radial water mist.

[0067] Exemplarily, the sealing part 21 is arranged as a hollow tubular body, so that the cooling water introduced by the first water joint 2 can flow into the internal passage of the sealing part 21.

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

[0069] Optionally, the outer periphery of the sealing part 21 is provided with external threads, and the first end of the combustion tube 1 is provided with internal threads matching the external threads at the accommodating cavity 103. The sealing part 21 is embedded in the accommodating cavity 103 and is threadedly connected with the combustion tube 1, so as to realize the fixed connection of the sealing part 21 and the combustion tube 1.

[0070] Optionally, as shown in Figure 5 , the end of the sealing plug 41 away from the sealing part 21 is provided with a groove 413, and the first end of the spring 42 is embedded in the groove 413. In this way, the stability of compression and recovery of the spring 42 can be improved, and the stability of movement of the sealing plug 41 relative to the combustion tube 1 can be improved, so as to avoid the deviation of the axis of the sealing plug 41 from the axis of the sealing part 21, thereby ensuring the centering of the sealing plug 41 and the sealing part 21.

[0071] In one embodiment, as shown in Figure 5 , the sealing part 21 is provided with a first sealing taper surface 211, and the sealing plug 41 is provided with a second sealing taper surface 412. The first sealing taper surface 211 abuts against the second sealing taper 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 taper surface 211. Specifically, the first sealing taper surface 211 is recessed towards the inside of the sealing part 21, and the second sealing taper surface 412 is protruded outwardly, so that the first sealing taper surface 211 and the second sealing taper surface 412 can better abut and cooperate, and at the same time, the centering of the sealing plug 41 and the sealing part 21 can be ensured. In this way, the external cooling water introduced by the first waterway connector 2 cannot enter the third water spraying channel 411, the first water spraying channel 101 is in a closed state, and the first water jet 3 stops spraying radial water mist.

[0072] In some embodiments, as shown in Figure 10 and Figure 11As shown, the composite coiled tubing comprises a first coiled tubing 5, which comprises a first outer tube 51 and a first inner tube 52, the first outer tube 51 is sleeved on the outer circumferential 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, and the first annular cavity 53 is connected with the first waterway joint 2; the second end of the first outer tube 51 is connected with the first end of the combustion tube 1, and the first end of the first outer tube 51 is provided with a water supplement disc 54, the water supplement disc 54 is provided with a first annular water spraying pipe 541, and a plurality of water supplement holes are arranged on the first annular water spraying pipe 541 in the circumferential direction, so that the first annular cavity 53 is filled 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, and 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 spraying pipe 541 is provided with a plurality of water supplement holes in the circumferential direction, and the plurality of water supplement holes can be uniformly arranged in the circumferential direction of the first reversing water spraying pipe, or can be arranged in the axial direction of the first reversing water spraying pipe, so that the first annular cavity 53 is filled with cooling water, heat exchange occurs between the cooling water and the pipe wall of the first coiled tubing 5, the cooling water absorbs the heat of the combustion tube 1, thereby cooling the first coiled tubing 5.

[0073] Specifically, the first waterway joint 2 is provided with a second hollow channel, which is in communication with the first annular cavity 53 to introduce cooling water into the first annular cavity 53, and the pressure of the sealing plug 41 is controlled by controlling the water pressure of the cooling water in the first annular cavity 53, so as to control the opening and closing of the first water spraying channel 101, and further control the radial water mist of the first water spraying head 3, thereby achieving the cooling of the casing and the combustion tube 1.

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

[0075] In one embodiment, as Figure 7 and Figure 11As shown, the first end of the combustion pipe 1 is provided with a water inlet hole 104 and a water return joint 11, the water inlet hole 104 is in communication with the first annular cavity 53, the water return pipe 542 is provided on the water supply disc 54, and the first end of the water return joint 11 is connected with the water return pipe 542; the cooling channel 105 is arranged in the combustion pipe 1, the cooling channel 105 is in a U shape, the first end of the cooling channel 105 is connected with the water inlet hole 104, and the second end of the cooling channel 105 is connected with the second end of the water return joint 11. It can be understood that the water inlet hole 104 is in communication with the first annular cavity 53, the external cooling water can enter the cooling channel 105 from the water inlet hole 104, the cooling water exchanges heat with the combustion pipe 1, the cooling water absorbs the heat of the combustion pipe 1, thereby cooling the combustion pipe 1; then the hot water is transported to the external cooling system on the ground by the water return pipe 542, the external cooling system continuously supplies the cooling water to the first annular cavity 53, so that the combustion pipe 1 can be effectively cooled, the combustion pipe 1 is prevented from being burned out in the high-temperature working environment, and the working reliability of the combustion pipe 1 is further improved.

[0076] It should be noted that the water inlet hole 104 can be provided with a plurality of cooling channels 105, and the plurality of water inlet holes 104 and cooling channels 105 are one-to-one corresponding; the water return pipe 542 can be provided with a plurality of cooling channels 105, and the plurality of water return pipes 542 and cooling channels 105 are one-to-one corresponding and connected, so as to increase the contact area of the cooling water and the combustion pipe 1 and improve the cooling efficiency. The second section of the combustion pipe 1 can be provided with a plug to ensure the sealing of the cooling channel 105.

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

[0078] In one embodiment, as shown in Figure 8As shown, the first end of the combustion pipe 1 is provided with a second waterway joint 13, the first end of the second waterway joint 13 is connected with the first annular cavity 53; the combustion pipe 1 is provided with a fourth water spraying channel along the axial direction thereof, the second end of the combustion pipe 1 is provided with a second spraying head 14, the first end of the fourth water spraying channel is connected with the second end of the second waterway joint 13, and the second end of the fourth water spraying channel is connected with the second spraying head 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 waterway joint 13 can introduce the water in the first annular cavity 53 into the fourth water spraying channel, so that the second spraying head 14 sprays the axial water mist to the gasification reaction zone of the underground gasification material layer, the axial water mist is mixed with oxygen underground to serve as the gasification agent, is sprayed into the gasification reaction zone, and along with the combustion of the coal, through the pyrolysis of the coal and a series of chemical reactions between the coal and the gasification agent, combustible gases such as H2, CO and CH4 are generated.

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

[0080] In one embodiment, as shown in Figure 3 and Figure 8 the first end of the combustion pipe 1 is provided with an electric signal transmission joint 15, the second end of the combustion pipe 1 is provided with a temperature measuring sensor 16 and an electric ignition device 17 (spark plug), the temperature measuring sensor 16 and the electric ignition device 17 are electrically connected with the electric signal transmission joint 15 through a cable; the water supplementing disc 54 is provided with a composite pipe cable 544, one end of the composite pipe cable 544 passes through the first annular cavity 53 and is connected with the electric signal transmission joint 15, so as 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 measuring sensor 16 can adopt the thermocouple in the prior art, and the temperature measuring sensor 16 can detect the temperature of the environment where the combustion pipe 1 is located. As shown in Figure 9 The inside of the composite pipe cable 544 can be provided with a plurality of cables, so as to realize the integration of the composite pipe cable 544.

[0081] In this embodiment, first, a combustible sleeve is pre-buried in the underground coal gasification material layer, then the combustion head is lowered to the gasification reaction zone of the underground gasification material layer at the bottom of the well through the sleeve, the second end of the combustion pipe 1 faces the gasification reaction zone, the combustion pipe 1 can separately transport the combustion-supporting gas, oxygen and water to the gasification reaction zone, the electric ignition device 17 can ignite the combustion-supporting gas, the temperature measuring sensor 16 can detect the temperature of the environment where the combustion pipe 1 is located in real time, the position of the composite coiled tubing is adjusted according to the temperature at the bottom of the well and the outlet gas composition, so as to realize the continuous retreating gasification.

[0082] In an embodiment not shown in the figure, the composite pipe cable 544 comprises a protective pipe and a cable, a filler layer is arranged in the internal space of the protective pipe, and the filler layer can provide insulation, fire resistance, corrosion resistance, fixation and other protection functions for the coated cable. Further, a layer or multiple layers of steel wire outer armor are arranged on the outside of the protective pipe, which can improve the tensile strength of the protective pipe. Specifically, the steel wire outer armor comprises a plurality of protective ribs made of steel wire, which can be arranged along the axis of the protective pipe and coated on the outer circumferential side of the protective pipe; the protective ribs can also be arranged in a spiral shape, and the spiral protective ribs are arranged in a spiral on the outer circumferential side of the protective pipe. The protective ribs not only increase the overall strength and tensile strength of the protective pipe, but also effectively prevent external impact forces from directly acting on the protective pipe during transportation of the composite pipe cable 544, thereby improving the protection capability of the composite pipe cable 544.

[0083] In some embodiments, as shown in Figure 12 and Figure 13 , the composite coiled tubing comprises a second coiled pipe 6, the second coiled pipe 6 comprises a second outer pipe 61 and a second inner pipe 62, the second outer pipe 61 is sleeved on the outer circumferential side of the second inner pipe 62, the inner diameter of the second outer pipe 61 is larger than the outer diameter of the second inner pipe 62, and a second annular cavity 63 is formed between the second inner pipe 62 and the second outer pipe 61; the second inner pipe 62 is connected to the first inner pipe 52 away from one end of the combustion pipe 1, and the second outer pipe 61 is connected to the first outer pipe 51 away from one end of the combustion pipe 1; a water supplement pipe 64 is arranged in the second annular cavity 63, a first end of the water supplement pipe 64 is connected to a ground cooling water system (such as a water pump), and a second end of the water supplement pipe 64 is arranged in the axial direction of the second inner pipe 62 and connected to the annular water spraying pipe; the water pump can continuously supplement cooling water to the water supplement pipe 64, so that the first coiled pipe 5, the combustion pipe 1 and the casing can be effectively cooled.

[0084] It should be noted that the first inner pipe 52 and the second inner pipe 62 can be welded and connected by laser welding or argon arc welding, and the first outer pipe 51 and the second outer pipe 61 can also be welded and connected by laser welding or argon arc welding. The foregoing composite pipe cable 544, combustion supporting pipe 543, water return pipe 542 and water supplement pipe 64 can be pulled into the second annular cavity 63 by using a traction device, for example, the composite pipe cable 544, the combustion supporting pipe 543, the water return pipe 542 and the water supplement pipe 64 are bundled and connected with a steel wire rope, and the steel wire rope is pulled by using a traction device to pass the composite pipe cable 544, the combustion supporting pipe 543, the water return pipe 542 and the water supplement pipe 64 into the second annular cavity 63. The second coiled pipe 6 can be a straight pipe, a bent pipe, or a modular design assembled by multiple pipes.

[0085] Of course, the water supply pipes 64 can be provided in plurality, and the annular water spraying pipes can also be provided in plurality, and the plurality of water supply pipes 64 are connected to the annular water spraying pipes one by one.

[0086] In some embodiments, as shown in Figure 12 The second end of the combustion pipe 1 is provided with a protective cover 7, and at least one through hole 71 is formed in the protective cover 7. In the process of the combustion pipe 1 exploring the bottom of the well, the protective cover 7 can protect the electric ignition device 17, the temperature sensor 16 and the second spray head 14 installed at the front end of the combustion pipe 1 from being damaged by external force. The working process of the embodiment is as follows: first, a flammable sleeve is pre-buried in the underground coal gasification layer, then the combustion pipe 1 is passed through the sleeve and is explored to the gasification reaction zone of the underground coal gasification layer at the bottom of the well, the second end of the combustion pipe 1 faces the gasification reaction zone, the combustion-supporting gas is injected into the bottom of the well through the through hole 71 of the protective cover 7, the electric ignition device 17 ignites the combustion-supporting gas, and the gas combustion generates high temperature, when the ambient temperature reaches 1000℃, the protective cover 7 is burned; then, the second spray head 14 sprays axial water mist, so that the coal in the gasification reaction zone is combusted in situ to produce flammable gases such as H2, CO and CH4.

[0087] It is to be understood that the terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms "comprises", "comprising", "includes", "including" and "has" are inclusive and therefore specify the presence of stated features, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and / or groups thereof. The method steps, processes, and operations described herein are not to be construed as necessarily requiring their performance in the particular order in which they are described, unless specifically identified as an order dependent step. It is also to be understood that additional or alternative steps can be employed.

[0088] Although the terms first, second, third, and the like can be used herein to describe various 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 be only used to differentiate one element, component, region, layer or section from another region, layer or section. Unless the context clearly indicates otherwise, terms such as "first", "second", and the like, and other ordinal terms, as used herein are used to modify two or more objects for descriptive purposes and are not meant to necessarily describe a temporal or chronological sequence unless explicitly stated otherwise. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of example embodiments.

[0089] The foregoing detailed description of the application has been presented for purposes of illustration and description. Various modifications and changes can be made to these embodiments without departing from the spirit and scope of the application. It is intended that the scope of the application should not be limited by the particular representative embodiments described above.

Claims

1. A composite coiled tubing, characterized by, The utility model relates to a kind of composite coiled tubing and its water injection control assembly, including: Combustion pipe, the combustion pipe includes oppositely arranged first end and second end, the combustion pipe is provided with first water injection channel, the combustion pipe is provided with second water injection channel along its radial direction, the first end of the first water injection channel is communicated with the first end of the second water injection channel; First waterway joint, it is arranged at the first end of the combustion pipe, the first waterway joint is connected with the second end of the first water injection channel, for introducing external cooling water; First spray head, it is arranged at the outer circumferential side of the combustion pipe, the first spray head is connected with the second end of the second water injection channel, for spraying radial water mist.

2. The composite coiled tubing of claim 1, wherein, The second end of the combustion pipe has ignition working condition, when the second end of the combustion pipe is in ignition working condition, cooling water enters the first spray head through the first water injection channel and the second water injection channel, part of radial water mist sprayed by the first spray head is sprayed on the wall surface of sleeve, and another part of radial water mist is sprayed on the outer circumferential side of the combustion pipe, to cool the sleeve and the combustion pipe.

3. The composite coiled tubing of claim 1 or 2, wherein, The second end of the first water injection channel is provided with water injection control assembly, and the water injection control assembly is used to control the opening and closing of the first water injection channel, in the case that the second end of the combustion pipe is in the gasification material layer mining completion condition, the first water injection channel is in closed state.

4. The composite coiled tubing of claim 3, wherein, The first waterway joint is provided with sealing portion close to the side of the combustion pipe, the first end of the combustion pipe is provided with accommodating cavity along its axial direction, the accommodating cavity is communicated with the first water injection channel, and the sealing portion is arranged in the accommodating cavity; The water injection control assembly includes sealing plug and spring, the sealing plug is slidably arranged in the accommodating cavity, the sealing plug is abutted with the sealing portion, the first end of the spring is connected with the sealing plug, the second end of the spring is connected with the wall surface of the accommodating cavity, the third water injection channel is arranged on the sealing plug, and the third water injection channel is communicated with the first water injection channel.

5. The composite coiled tubing of claim 4, wherein, The sealing portion is provided with first sealing cone surface, the sealing plug is provided with second sealing cone surface, the first sealing cone surface is abutted with the second sealing cone surface, and the end of the third water injection channel away from the first water injection channel is abutted with the first sealing cone surface.

6. The composite coiled tubing of claim 4, wherein, The composite coiled tubing includes first continuous pipe, the first continuous pipe includes first outer pipe and first inner pipe, the first outer pipe is sleeved on the outer circumferential side of the first inner pipe, the inner diameter of the first outer pipe is greater than the outer diameter of the first inner pipe, and the first annular cavity is formed between the first inner pipe and the first outer pipe, and the first annular cavity is connected with the first waterway joint; The second end of the first outer pipe is connected with the first end of the combustion pipe, the first end of the first outer pipe is provided with water supplementing disc, the first annular cavity is filled with the cooling water by the first annular water injection pipe on the water supplementing disc along its circumferential direction being provided with a plurality of water supplementing holes.

7. The composite coiled tubing of claim 6, wherein, The first end of the combustion pipe 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 arranged through the water supply disc, and the first end of the water return joint is connected with the water return pipe. A cooling channel is arranged in the combustion pipe, the cooling channel is in a U shape, the first end of the cooling channel is connected with the water inlet hole, and the second end of the cooling channel is connected with the second end of the water return joint.

8. The composite coiled tubing of claim 6, wherein, A combustion supporting pipeline is arranged through the water supply disc, the first end of the combustion pipe is provided with a combustion supporting joint, the first end of the combustion supporting pipeline passes through the first annular cavity and is connected with the first end of the combustion supporting joint. A combustion supporting channel is arranged in the combustion pipe, the combustion supporting channel is connected with the second end of the combustion supporting joint, and the end of the combustion supporting channel away from the combustion supporting joint extends towards the second end of the combustion pipe.

9. The composite coiled tubing of claim 6, wherein, The first end of the combustion pipe is provided with a second water route joint, and the first end of the second water route joint is connected with the first annular cavity. The second end of the combustion pipe is provided with a second spray head, the first end of the fourth water spraying channel is connected with the second end of the second water route joint, and the second end of the fourth water spraying channel is connected with the second spray head, so as to provide the water mist required by the underground gasification reaction zone.

10. The composite coiled tubing of claim 6, wherein, The first end of the combustion pipe is provided with an electric signal transmission joint, the second end of the combustion pipe is provided with a temperature measuring sensor and an electric ignition device, and the temperature measuring sensor and the electric ignition device are electrically connected with the electric signal transmission joint through a cable. A composite pipe cable is arranged on the water supply disc, one end of the composite pipe cable passes through the first annular cavity and is connected with the electric signal transmission joint.

11. The composite coiled tubing of claim 6, wherein, The composite coiled tubing comprises a second coiled pipe, the second coiled pipe comprises a second outer pipe and a second inner pipe, the second outer pipe is sleeved on the outer circumferential 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 with the first inner pipe away from the first end of the combustion pipe, the second outer pipe is connected with the first outer pipe away from the second end of the combustion pipe, and a water supply pipe is arranged in the second annular cavity, one end of the water supply pipe is connected with the annular water spraying pipe.

12. The composite coiled tubing of any one of claims 1 to 11, wherein, The second end of the combustion pipe is provided with a protective cover, and at least one through hole is arranged on the protective cover.

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