A multi-row horizontal well layered production device and method for natural gas hydrates

Abstract

This invention provides a multi-row horizontal well layered extraction device and method for natural gas hydrates. The device includes: a guide pipe; multiple evenly distributed interfaces on the lower side of the guide pipe from top to bottom, each interface being connected to a wellbore via a corrugated metal hose; multiple wellbores arranged in parallel; each wellbore being connected to an adjustment mechanism, which is mounted on the guide pipe and can adjust the vertical position of the corresponding wellbore. In this invention, the wellbore is connected to the guide pipe via a corrugated metal hose, therefore the connection between the wellbore and the guide pipe is not fixed. Furthermore, an adjustment mechanism for adjusting the wellbore position is provided. This adjustment mechanism allows for adjustment of the distance between the wellbores. When a wellbore layer fails, by reasonably adjusting the spacing between the wellbores, extraction can still be carried out on the failed layer.

Description

Technical Field

[0001] This invention relates to the field of natural gas hydrate extraction equipment technology, and in particular to a multi-row horizontal well stratified extraction device and method for natural gas hydrate. Background Technology

[0002] Natural gas hydrates are considered the world's largest untapped mineral energy source, possessing significant advantages such as wide distribution, enormous reserves, and cleanliness. Given my country's resource situation of "oil and gas shortage," achieving large-scale, low-cost development of natural gas hydrates as soon as possible is of great significance for ensuring national energy security and meeting my country's demand for clean energy. To date, four trial extractions of marine natural gas hydrates have been conducted internationally, verifying that horizontal well extraction methods produce significantly more gas than vertical well extraction methods.

[0003] It is foreseeable that horizontal well extraction will be the main method for extracting natural gas hydrates worldwide in the future. However, from the perspective of large-scale, commercial extraction of natural gas hydrates, the extraction radius of a single well is far from meeting the extraction needs. Therefore, multi-row horizontal well stratified extraction will be the primary mining technology. However, at present, the spacing of multi-row horizontal well stratification is fixed and cannot be adjusted according to the needs of extraction. Moreover, when a horizontal well in a certain layer fails, the entire pipeline will be abandoned, affecting the extraction efficiency.

[0004] Therefore, it is necessary to provide a new multi-row horizontal well stratified production device and method for natural gas hydrates to solve the above-mentioned technical problems. Summary of the Invention

[0005] To address the technical problems of fixed spacing between layers in existing multi-row horizontal wells, the inability to adjust the spacing between layers according to mining needs, and the abandonment of the entire pipeline due to a layer failure in a certain layer, this invention provides a multi-row horizontal well layered mining device and method for natural gas hydrates.

[0006] This invention is achieved through the following technical solution:

[0007] A multi-row horizontal well layered production device for natural gas hydrate includes: a guide pipe; the lower end of the guide pipe has multiple evenly distributed interfaces on its side from top to bottom, each interface being connected to a wellbore via a corrugated metal hose; the multiple wellbores are arranged in parallel.

[0008] Each wellbore is connected to an adjustment mechanism, which is mounted on the guide tube and can adjust the vertical position of the corresponding wellbore.

[0009] Preferably, the adjustment mechanism includes two parallel mounting plates installed on the side of the guide tube, and the mounting plates are perpendicular to the axis of the guide tube; two sliding rods are connected between the two mounting plates, and an adjustment block is slidably sleeved on the two sliding rods. Both sides of the adjustment block are fixedly connected to the side of the corresponding wellbore through connecting rods; a hydraulic cylinder is installed on one of the mounting plates, and the output shaft of the hydraulic cylinder is connected to the adjustment block.

[0010] Furthermore, a connecting block is fixedly connected to the side of the conduit, and the frame plate is fixedly connected to the connecting block by bolts.

[0011] Preferably, a pressure pump is installed inside one end of the wellbore that is connected to the corrugated metal hose, and the surface of the wellbore is provided with evenly distributed wellbores, with overflow valves installed on the wellbores.

[0012] Furthermore, a filter mechanism is connected to the other end of the overflow valve.

[0013] Furthermore, the filtration mechanism includes a feed pipe and a screen, with the other end of the overflow valve fixedly connected to the feed pipe, and the other end of the feed pipe fixedly connected to the screen.

[0014] Preferably, the upper end of the conduit is fixedly fitted with a sleeve.

[0015] Preferably, a temperature sensor and a flow meter are installed inside the upper end of the conduit.

[0016] Preferably, a pressure sensor is installed at one end of the wellbore.

[0017] A method for layered production of natural gas hydrates using multi-row horizontal wells, based on the aforementioned apparatus, includes:

[0018] a. The guide pipe penetrates the overburden layer, with its lower end inserted into the hydrate reservoir and contacting the underlying layer. Each wellbore is located within the hydrate reservoir.

[0019] b. Extraction of natural gas hydrates through wellbores;

[0020] c. When it is necessary to adjust the spacing between adjacent wells, the vertical position of the corresponding well is adjusted by adjusting the structure.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] The multi-row horizontal well layered mining device for natural gas hydrates described in this invention has well casings connected to conduits via corrugated metal hoses. Therefore, the connection between the well casings and conduits is not fixed. Furthermore, an adjustment mechanism for adjusting the position of the well casings is provided. This adjustment mechanism allows for adjustment of the distance between each well casing, meaning the spacing between each layer of horizontal wells can be adjusted according to actual needs. Moreover, when a well casing layer fails, the spacing between the well casing layers can be adjusted appropriately, allowing mining to continue even in the failed layer. This not only improves mining efficiency but also facilitates continuous mining.

[0023] Furthermore, the adjustment mechanism includes a slide bar, an adjustment block, a hydraulic cylinder, etc. The hydraulic cylinder drives the adjustment block to slide up and down along the slide bar, thereby causing the corresponding wellbore to move up and down. This adjustment mechanism has a simple structure.

[0024] Furthermore, the frame plate is fixedly connected to the connecting block on the outer surface of the conduit by bolts, allowing the frame plate to be easily and quickly assembled and disassembled.

[0025] Furthermore, a pressure pump and an overflow valve are installed in each wellbore. During the mining process, the pressure pumps in each wellbore and the overflow valves on the wellbore can be opened sequentially from top to bottom to carry out mining, or the pressure pumps in each wellbore and the overflow valves on the wellbore can be opened sequentially from bottom to bottom to carry out mining. The mining sequence can be adjusted arbitrarily as needed, facilitating mining through multiple mining methods.

[0026] Furthermore, by setting up a filtration mechanism, impurities can be prevented from entering the wellbore through the overflow valve and causing blockages during the mining process, thus meeting the needs of continuous mining.

[0027] Furthermore, by installing a sleeve to protect the section of the conduit located within the cover layer, the service life of the conduit is improved.

[0028] Furthermore, a pressure sensor is installed at one end of the wellbore, which facilitates the detection of the pressure in the layer where the wellbore is located. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the structure of the multi-row horizontal well layered mining device for natural gas hydrates of the present invention;

[0030] Figure 2 This is a schematic diagram of the sleeve structure in this invention;

[0031] Figure 3 This is a schematic diagram of the adjustment mechanism in this invention;

[0032] Figure 4 This is a schematic diagram of the well shaft structure in this invention;

[0033] Figure 5 This is a schematic diagram of the feed pipe in this invention.

[0034] Labels in the diagram: 1. Conduit; 2. Interface; 3. Corrugated metal hose; 4. Well shaft; 5. Conveying pipe; 6. Connecting rod; 7. Fixing ring; 8. Pipe sleeve; 9. Hydraulic cylinder; 10. Connecting block; 11. Rib; 12. Slide rod; 13. Support plate; 14. Adjusting block; 15. Pipe plug; 16. Pressure sensor; 17. Pressure pump; 18. Wellbore; 19. Overflow valve; 20. Feed pipe; 21. Screen. Detailed Implementation

[0035] To further understand the present invention, the present invention will be described below with reference to embodiments. These descriptions are only for further explaining the features and advantages of the present invention and are not intended to limit the claims of the present invention.

[0036] Please refer to Figure 1 , Figure 2 , Figure 3 , Figure 4 and Figure 5 ,in, Figure 1 This is a schematic diagram of the structure of the multi-row horizontal well layered mining device for natural gas hydrates of the present invention; Figure 2 This is a schematic diagram of the sleeve structure in this invention;

[0037] Figure 3 This is a schematic diagram of the adjustment mechanism in this invention; Figure 4 This is a schematic diagram of the well shaft structure in this invention; Figure 5 This is a schematic diagram of the feed pipe in this invention.

[0038] Please refer to Figure 1 The multi-row horizontal well stratified mining device for natural gas hydrates of the present invention includes: a guide pipe 1, a wellbore 4, a filtration mechanism and an adjustment mechanism.

[0039] like Figure 1 , Figure 3 and Figure 4 As shown, the lower end of the conduit 1 has multiple evenly distributed interfaces 2 on its side from top to bottom. Each interface 2 is connected to a wellbore 4 via a corrugated metal hose 3. A pressure pump 17 is installed inside one end of the wellbore 4 connected to the corrugated metal hose 3. The surface of the wellbore 4 has evenly distributed wellbores 18, each with an overflow valve 19 installed. The other end of the overflow valve 19 is connected to a filter mechanism. The multiple wellbores 4 are arranged in parallel.

[0040] Each wellbore 4 is connected to an adjustment mechanism, which includes two parallel mounting plates 13, sliding rods 12, hydraulic cylinders 9, adjusting blocks 14, and connecting rods 6. The two parallel mounting plates 13 are installed on the side of the guide tube 1, and the two mounting plates 13 are fixedly connected by two symmetrically arranged sliding rods 12. The upper surface of the upper mounting plate 13 is equipped with a hydraulic cylinder 9. The output end of the hydraulic cylinder 9 passes through the adjacent mounting plate 13 and is fixedly connected to an adjusting block 14. The adjusting block 14 has sliding holes that match the two sliding rods 12. The adjusting block 14 is slidably sleeved on the two sliding rods 12. Both sides of the adjusting block 14 are fixedly connected to the side of the wellbore 4 by connecting rods 6.

[0041] It should be noted that during operation, the conduit 1 penetrates the overburden layer, with its lower end inserted into the hydrate reservoir, contacting the underlying layer. Each wellbore 4 is located within the hydrate reservoir. When extracting through the wellbore 4, the pressure pump 17 inside the wellbore 4 and the overflow valve 19 on the wellbore 18 are opened to slowly reduce the pressure inside the wellbore 4. The pressure difference causes the pore pressure of the natural gas hydrate reservoir to gradually decrease below the phase equilibrium pressure of the natural gas hydrate, promoting the decomposition of the natural gas hydrate. At the same time, water and gas generated by the decomposition of hydrate around the wellbore 4 are extracted and introduced into the conduit 1 until the extraction target of the natural gas hydrate in the current reservoir area is achieved. Furthermore, by activating the hydraulic cylinder 9, the adjusting block 14 can be driven to slide on the slide rod 12. The movement of the adjusting block 14 drives the movement of the wellbore 4 through the connecting rod 6, thereby allowing the wellbore 4 to be moved up and down to adjust the distance between each wellbore 4.

[0042] refer to Figure 1 As shown, the upper end of the conduit 1 is connected to a transport pipe 5, and the upper end of the transport pipe 5 is connected to an offshore drilling platform. The transport pipe 5 facilitates the transportation of mining materials.

[0043] refer to Figure 2 As shown, a fixing ring 7 is fixedly sleeved on the upper end of the conduit 1, and a pipe sleeve 8 is fixedly connected to the fixing ring 7 by bolts. The pipe sleeve 8 protects the section of the conduit 1 located in the soil cover layer, thereby improving the service life of the conduit 1.

[0044] refer to Figure 4 and Figure 5 As shown, the filtration mechanism includes a feed pipe 20 and a screen 21. The other end of the overflow valve 19 is fixedly connected to the feed pipe 20, and the other end of the feed pipe 20 is fixedly connected to a matching screen 21.

[0045] It should be noted that during the mining process, the screen 21 installed in the feed pipe 20 can play a filtering role, preventing impurities from entering the wellbore 18 through the overflow valve 19 and causing blockage, thus meeting the needs of continuous mining.

[0046] refer to Figure 3 As shown, the side of the conduit 1 is fixedly connected with evenly distributed connecting blocks 10, and the frame plate 13 is fixedly connected to the connecting blocks 10 by bolts, so that the frame plate 13 can be easily and quickly assembled and disassembled.

[0047] refer to Figure 3 As shown, the lower surface of the connecting block 10 is fixedly connected to the side of the conduit 1 by the rib 11. The rib 11 makes the structure of the connecting block 10 more stable.

[0048] A temperature sensor and a flow meter (the temperature sensor and flow meter are existing mature devices and are not shown in the figure) are installed in the upper end of the conduit 1. The temperature sensor and flow meter are connected to the data acquisition device of the external drilling platform. The temperature and flow of hydrate in the conduit 1 can be easily observed through the temperature sensor and flow meter.

[0049] refer to Figure 5 As shown, a pressure sensor 16 is installed at one end of the wellbore 4. The pressure sensor 16 is connected to the data acquisition device of the external drilling platform. The pressure sensor 16 facilitates the detection of the pressure of the layer where the wellbore 4 is located.

[0050] refer to Figure 1 As shown, the lower end of the conduit 1 is sealed by the tube plug 15, so that the lower end of the conduit 1 can remain sealed.

[0051] The working principle provided by this invention is as follows: During use, the conduit 1 penetrates the overburden layer, with its lower end inserted into the hydrate reservoir, contacting the underlying layer. Each wellbore 4 is located within the hydrate reservoir. When extracting through the wellbore 4, the pressure pump 17 inside the wellbore 4 and the overflow valve 19 on the wellbore 18 are opened to slowly reduce the pressure inside the wellbore 4. The pressure difference causes the pore pressure of the natural gas hydrate reservoir to gradually decrease below the phase equilibrium pressure of the natural gas hydrate, promoting the decomposition of the natural gas hydrate. Simultaneously, water and gas generated by the decomposition of the hydrate around the wellbore 4 are extracted and introduced into the conduit 1 until the extraction target of the current reservoir area is achieved. Thus, during the extraction process, the pressure pump 17 inside each wellbore 4 and the overflow valve 19 on the wellbore 18 can be opened sequentially from top to bottom, according to... Mining can be carried out from top to bottom, or the pressure pumps 17 and overflow valves 19 on the wellbore 18 can be opened sequentially from bottom to bottom. Mining can be carried out in a bottom-up order, and the mining sequence can be adjusted arbitrarily as needed. Multiple mining methods facilitate mining. Moreover, by activating the hydraulic cylinder 9, the adjusting block 14 can be driven to slide on the slide rod 12. The movement of the adjusting block 14 drives the movement of the wellbore 4 through the connecting rod 6, thereby adjusting the wellbore 4 up and down. This allows the distance between each wellbore 4 to be adjusted, that is, the spacing between each layer of horizontal wells can be adjusted according to actual needs. Furthermore, when a layer of wellbore 4 fails, by reasonably adjusting the spacing between each layer of wellbore 4, the failed layer can still be mined, thereby not only improving mining efficiency but also facilitating continuous mining.

[0052] A method for exploiting marine natural gas hydrates using a multi-row horizontal well stratified exploitation device includes the following steps:

[0053] a. First, install the conduit 1 through the overburden layer. The lower end of the conduit 1 is inserted into the hydrate reservoir and contacts the underlying layer. Each wellbore 4 is located within the hydrate reservoir.

[0054] b. Then, when extracting through well 4, open the pressure pump 17 inside well 4 and the overflow valve 19 on the wellbore 18 to slowly reduce the pressure inside well 4. Use the pressure difference to gradually reduce the pore pressure of the natural gas hydrate reservoir to below the phase equilibrium pressure of the natural gas hydrate, promoting the decomposition of the natural gas hydrate. At the same time, extract the water and gas generated by the decomposition of hydrate around well 4 and introduce them into the conduit 1 until the extraction target of the natural gas hydrate in the current reservoir area is achieved.

[0055] c. During adjustment, by activating the hydraulic cylinder 9, the adjusting block 14 can slide on the slide rod 12. The movement of the adjusting block 14 drives the movement of the well barrel 4 through the connecting rod 6, thereby allowing the well barrel 4 to be moved up and down to adjust the distance between each well barrel 4.

[0056] All electrical components in this invention are connected to an external main controller and 220V AC mains power via transformers. The main controller can be a conventional known device such as a computer. The electrical components provided in this invention are used based on the structural features of the product in this technical solution. The product will be adjusted and modified after purchase to better match and conform to the technical solution of this invention. It is an optimal application of this technical solution. The product model can be replaced and modified according to the required technical parameters. It is well known to those skilled in the art. Therefore, those skilled in the art can clearly obtain the corresponding usage effect through the technical solution provided by this invention.

[0057] The above description is merely an embodiment of the present invention and does not limit the scope of protection of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the scope of protection of the present invention.

Claims

1. A device for separate layer production of natural gas hydrates in multi-row horizontal wells, characterized in that it comprises: include: The conduit (1) has multiple evenly distributed interfaces (2) on the side of the lower end of the conduit (1) from top to bottom, and each interface (2) is connected to a well shaft (4) through a corrugated metal hose (3); the multiple well shafts (4) are arranged in parallel. Each wellbore (4) is connected to an adjustment mechanism, which is installed on the guide tube (1) and can adjust the position of the corresponding wellbore (4) in the vertical direction.

2. The apparatus for separate layer production of natural gas hydrates by multiple horizontal well rows according to claim 1, characterized in that, The adjustment mechanism includes two parallel mounting plates (13) installed on the side of the guide tube (1), and the mounting plates (13) are perpendicular to the axis of the guide tube (1); two sliding rods (12) are connected between the two mounting plates (13), and an adjustment block (14) is slidably sleeved on the two sliding rods (12). Both sides of the adjustment block (14) are fixedly connected to the side of the corresponding wellbore (4) through connecting rods (6); a hydraulic cylinder (9) is installed on one of the mounting plates (13), and the output shaft of the hydraulic cylinder (9) is connected to the adjustment block (14).

3. The apparatus according to claim 2, wherein, A connecting block (10) is fixedly connected to the side of the conduit (1), and the frame plate (13) is fixedly connected to the connecting block (10) by bolts.

4. The apparatus according to claim 1, wherein, A pressure pump (17) is installed in one end of the well barrel (4) that is connected to the corrugated metal hose (3). The surface of the well barrel (4) is provided with evenly distributed well holes (18), and an overflow valve (19) is installed on the well holes (18).

5. The apparatus according to claim 4, wherein, The other end of the overflow valve (19) is connected to a filter mechanism.

6. The apparatus for separate layer production of natural gas hydrates by multiple horizontal well rows according to claim 5, characterized in that, The filtration mechanism includes a feed pipe (20) and a screen (21). The other end of the overflow valve (19) is fixedly connected to the feed pipe (20), and the other end of the feed pipe (20) is fixedly connected to the screen (21).

7. The multi-row horizontal well stratified production device for natural gas hydrates according to claim 1, characterized in that, The upper end of the conduit (1) is fixedly fitted with a sleeve (8).

8. The multi-row horizontal well stratified production device for natural gas hydrates according to claim 1, characterized in that, A temperature sensor and a flow meter are installed inside the upper end of the conduit (1).

9. The multi-row horizontal well stratified production device for natural gas hydrates according to claim 1, characterized in that, A pressure sensor (16) is installed at one end of the wellbore (4).

10. A method for layered production of natural gas hydrates using multiple horizontal wells, characterized in that, The apparatus according to any one of claims 1-9 comprises: a. Make the guide pipe (1) penetrate the overburden layer, and insert the lower end of the guide pipe (1) into the hydrate reservoir, abutting the underlying layer. Each well (4) is located in the hydrate reservoir. b. Extracting natural gas hydrates through wellbore (4); c. When it is necessary to adjust the spacing between adjacent wellbores (4), the position of the corresponding wellbore (4) in the vertical direction is adjusted by adjusting the structure.

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