A drilling device for natural gas hydrate simulation mining test in a high gravity field

Abstract

The present invention relates to the technical field of natural gas hydrate extraction, and specifically discloses a drilling device for simulating natural gas hydrate extraction in a hypergravity field. The device comprises a high-pressure model box, an external support provided with a support, a drive device slidably mounted on the support, and a rotary cutter disposed at the output end of the drive device, the rotary cutter being located within the high-pressure model box. The present invention has the advantage of utilizing only a single drive device to achieve both rotation and feed, resulting in a compact structure and improved operation in a high hypergravity field environment.

Description

Technical Field

[0001] The invention relates to the technical field of natural gas hydrate mining, in particular to a drilling device for natural gas hydrate simulation mining test in a hypergravity field. Background Art

[0002] Due to the hidden nature and complexity of the natural gas hydrate extraction process, field trials require significant investment and pose safety concerns, making physical simulations in the laboratory an inevitable trend. However, existing simulations are mostly conducted under normal gravity, failing to reflect the true stress field of the hydrate extraction process. Models under hypergravity, on the other hand, can compensate for stress losses by overloading. Conducting scaled-down model experiments in hypergravity—using a 1 / nth-scaled model in a hypergravity field with n times the gravity—can offer high accuracy and cost-effectiveness, and is a key research direction in the field of natural gas hydrate extraction both domestically and internationally.

[0003] Currently, there are few simulation facilities for hydrate extraction in hypergravity fields, and the simulation process is incomplete. Existing extraction simulations focus solely on the hydrate decomposition process, with no public reports on the extraction operation itself. Extraction operations involve drilling and advancing, and must be performed in a hypergravity field hundreds of times greater than gravity. Centrifugal forces hundreds of times greater than gravity cause significant deformation of the structure, making it increasingly difficult to achieve. A compact and simple device is required to accomplish this process. Summary of the Invention

[0004] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a drilling device for natural gas hydrate simulation mining test in a high gravity field.

[0005] The object of the present invention is achieved through the following technical solution: a drilling device for a high-gravity field natural gas hydrate simulation mining test, comprising a high-pressure model box, a bracket is provided on the outside of the high-pressure model box, a driving device is slidably provided on the bracket, a rotary cutter is provided at the output end of the driving device, and the rotary cutter is located inside the high-pressure model box.

[0006] Specifically, the bracket includes a connecting rod and two guide rods. The two guide rods are arranged in parallel and one end of each is fixed on the high-pressure model box. The other ends of the two guide rods are connected by the connecting rod.

[0007] Specifically, the driving device includes a driving motor and a screw rod. The driving motor is fixed on a mounting plate. The mounting plate is slidingly connected to the two guide rods through linear bearings. The screw rod is connected to the output shaft of the driving motor. The rotary cutter is fixed at one end of the screw rod. A nut is fixed on the high-pressure model box. The screw rod is threadedly connected to the nut.

[0008] Specifically, a mounting hole is provided on the high-pressure model box, and the screw rod extends into the high-pressure model box through the mounting hole. A composite seal is provided on the inner side of the high-pressure model box at the mounting hole. The composite seal is fixed on the high-pressure model box for sealing the high-pressure model box and the screw rod.

[0009] Specifically, the rotary cutter includes a cutter rod and a spiral blade, the spiral blade is spirally fixed on the cutter rod, and cutting edges are provided at the edge of one end of the spiral blade and the end of the cutter rod. A fixing seat is provided at one end of the cutter rod, and a fixing hole is provided on the fixing seat for installing the rotary cutter.

[0010] Specifically, a knife barrel is sleeved on the outer side of one end of the rotary cutter connected to the screw rod, and the knife barrel is rotatably arranged on the screw rod.

[0011] Specifically, a connecting plate is provided at one end of the screw rod, a ball bearing ring is provided on the connecting plate, one end of the ball bearing ring is fixed to the connecting plate, and the other end is fixedly connected to the knife cylinder.

[0012] Specifically, the cutter cylinder includes a supporting cylinder and a storage cylinder. The diameter of the storage cylinder is larger than that of the supporting cylinder. The storage cylinder is connected to the supporting cylinder, and the connection point is a conical structure. The storage cylinder is connected to the ball bearing ring.

[0013] Specifically, a laser displacement sensor is provided on the connecting rod.

[0014] The present invention has the following advantages:

[0015] 1. The drilling device of the present invention uses only one drive motor to achieve both rotation and feeding, has a compact structure, and is easier to work in a high-gravity field environment;

[0016] 2. A cutter barrel is set at one end of the screw rod. The rotary cutter passes through the cutter barrel to realize simulated mining and wellhead support operations. The cutter barrel and the rotary cutter are fed together and do not rotate, so there will be no friction interference to the mined layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the overall structure of the drilling device of the present invention;

[0018] Figure 2 for Figure 1 Schematic diagram of the enlarged structure at A in the middle;

[0019] Figure 3 It is a schematic diagram of the rotary cutter structure of the present invention;

[0020] Figure 4 It is a schematic diagram of the knife barrel structure of the present invention;

[0021] In the figure: 1-high-pressure model box, 2-rotating knife, 21-knife rod, 22-spiral blade, 23-fixed seat, 3-knife cylinder, 31-storage cylinder, 32-support cylinder, 4-nut, 5-guide rod, 6-screw rod, 7-mounting plate, 8-linear bearing, 9-drive motor, 10-connecting rod, 11-laser displacement sensor, 12-composite seal, 13-connecting plate, 14-fixing nut, 15-ball shaft ring. DETAILED DESCRIPTION

[0022] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only for the purpose of explaining the present invention and are not intended to limit the present invention. That is, the embodiments described herein are only some embodiments of the present invention, not all embodiments. Generally, the components of the embodiments of the present invention described and illustrated in the drawings herein can be arranged and designed in various different configurations.

[0023] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention as claimed, but is merely intended to represent selected embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative work are within the scope of protection of the present invention.

[0024] It should be noted that relational terms such as "first" and "second" are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "includes," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus comprising a list of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus. In the absence of further limitations, an element defined by the phrase "comprising a..." does not preclude the presence of additional identical elements in the process, method, article, or apparatus comprising the element.

[0025] The present invention will be further described below in conjunction with the accompanying drawings, but the protection scope of the present invention is not limited to the following description.

[0026] like Figures 1 to 4As shown, a drilling device for simulating the mining of natural gas hydrates in a hypergravity field comprises a high-pressure model box 1, a bracket provided on the outside of the high-pressure model box 1, a drive device slidably provided on the bracket, a rotary cutter 2 provided at the output end of the drive device, and the rotary cutter 2 located within the high-pressure model box 1. The drilling device of this embodiment is used to simulate the mining of natural gas hydrates in a hypergravity field. When in use, the drilling device needs to be mounted on a high-speed rotating centrifuge so that the entire device operates in a hypergravity field. The high-pressure model box 1 is filled with high-pressure liquid to simulate a deep-sea environment. During operation of the centrifuge, the direction of the centrifugal force is consistent with the drilling direction of the rotary cutter 2 of the drilling device. During drilling, the drive device drives the rotary cutter 2 to rotate and feed simultaneously. Using one drive device, two actions are performed, the structure is compact, and it is easier to operate in a hypergravity environment. The bracket is fixed to the high-pressure model box 1 and is used to mount the drive device and provide guidance. When the drive device is operating, it can form a feed along the bracket slideway.

[0027] Furthermore, the bracket includes a connecting rod 10 and two guide rods 5, the two guide rods 5 are arranged in parallel and one end of each is fixed on the high-pressure model box 1, the other ends of the two guide rods 5 are connected through the connecting rod 10, the driving device includes a driving motor 9 and a screw rod 6, the driving motor 9 is fixed on the mounting plate 7, the mounting plate 7 and the two guide rods 5 are slidingly connected through linear bearings 8 respectively, the screw rod 6 is connected to the output shaft of the driving motor 9, the rotary cutter 2 is fixed on one end of the screw rod 6, a nut 4 is fixed on the high-pressure model box 1, and the screw rod 6 is threadedly connected to the nut 4. In this embodiment, the two guide rods 5 are arranged in parallel along the drilling direction, and the drive motor 9 is fixed to the mounting plate 7 by bolts. Bearing mounting holes are provided at both ends of the mounting plate 7. The linear bearings 8 are placed in the bearing mounting holes and are fixedly connected to the mounting plate 7 by bolts. The inner ring of the linear bearing 8 is set on the guide rod 5, so that the drive motor 9 can slide along the guide rod 5. The output shaft of the drive motor 9 is fixedly connected to the screw rod 6. A nut 4 is fixedly provided on the high-pressure model box 1. The screw rod 6 is threadedly connected to the nut 4. The drive motor 9 drives the screw rod 6 to rotate when it rotates. The screw rod 6 is connected with the nut 4 by thread, and the position of the nut 4 remains unchanged. When the screw rod 6 and the nut 4 rotate relative to each other, the screw rod 6 will move axially. The cooperation between the nut 4 and the guide rod 5 can make the drive motor 9 drive the rotary cutter 2 to rotate and feed at the same time during rotation, thereby realizing drilling into the simulated mining layer. The structure is simple and light, and it can work reliably in a supergravity environment. The speed of the screw rod 6 moving in the axial direction is determined by the rotation speed of the drive motor 9 and the screw rod 6 thread pitch, and the thread pitch can be designed according to actual test requirements.

[0028] Furthermore, a mounting hole is provided on the high-pressure model box 1, and the screw rod 6 extends into the high-pressure model box 1 through the mounting hole. A composite seal 12 is provided on the inner side of the high-pressure model box 1 at the mounting hole. The composite seal 12 is fixed on the high-pressure model box 1 to seal the high-pressure model box 1 and the screw rod 6. Since the drive motor 9 is provided on the outside of the high-pressure model box 1 and the rotary cutter 2 is provided on the inside of the high-pressure model box 1, the screw rod needs to pass through the high-pressure model box 1 to be connected to the rotary cutter 2. The high-pressure model box 1 is in a high-pressure environment. During the drilling process, the high-pressure model box 1 needs to always maintain a high-pressure environment. Therefore, in this embodiment, a composite seal 12 is provided between the screw rod 6 and the high-pressure model box 1 to achieve sealing, so as to prevent the inside of the high-pressure model box 1 from being connected to the outside through the mounting hole. The composite seal 12 is provided on the inside of the high-pressure model box 1, and the composite seal 12 is sleeved on the outside of the screw rod 6 and fixed to the high-pressure model box 1 by bolts.

[0029] Furthermore, the rotary cutter 2 includes a cutter rod 21 and a spiral blade 22, the spiral blade 22 is spirally fixed on the cutter rod 21, and a cutting edge is provided at the edge of one end of the spiral blade 22 and the end of the cutter rod 21. A fixing seat 23 is provided at one end of the cutter rod 21, and a fixing hole is provided on the fixing seat 23 for installing the rotary cutter 2. The rotary cutter in this embodiment adopts a structure composed of a cutter rod 21 and a spiral blade 22. Cutting edges are provided at one end of the spiral blade 22 and the end of the cutter rod 21. Cutting can be performed simultaneously by the two cutting edges during drilling. The drilling device in this embodiment works in a hypergravity field hundreds of times that of gravity. The working environment is harsh and the structure is subjected to extremely large centrifugal force. The soil drilled in the hypergravity field is also subjected to a centrifugal force hundreds of times that of gravity. If an ordinary cylindrical drill rod is used, the soil cannot be drilled and the soil cannot move in the opposite direction of the centrifugal force. In order to enable the drilled soil to move in the opposite direction of the centrifugal force, a spiral tool is used in this embodiment. The cutter rod 21 is used for drilling, and the drilled soil moves along the spiral blade 22 in the opposite direction of the centrifugal force. In a specific embodiment, the spiral lead of the spiral blade 22 can be designed according to the magnitude of the centrifugal force so that the friction force of the spiral blade 22 on the soil is greater than the centrifugal force, thereby achieving drilling of the soil; the cutter rod 21 is fixed to the end of the screw rod 6 through a fixing seat 23.

[0030] Furthermore, a cutter barrel 3 is externally sleeved on one end of the rotary cutter 2 connected to the screw rod 6, and the cutter barrel 3 is rotatably mounted on the screw rod 6. The cutter barrel 3 in this embodiment is used to support drilling. In the prior art, when a rotary drum-type drill tool is used, the rotation will cause friction on the surrounding mined soil. This friction will have an additional impact on the stability of the mining layer and cause additional decomposition of natural gas hydrates, thereby resulting in a large experimental error. At the same time, in the actual mining process of a well, one section is mined and one section is supported. In this embodiment, a rotary cutter 2 is used for drilling, and the outer cutter barrel 3 is fed to support the mining section. The non-rotation of the cutter barrel 3 has no additional impact on the mining layer. One end of the cutter barrel 3 is rotatably connected to the screw rod 6. After the cutter barrel 3 enters the mining layer, the static friction at the contact point with the mining layer prevents the cutter barrel 3 from rotating with the screw rod 6, thereby achieving a supporting effect.

[0031] Furthermore, a connecting plate 13 is provided at one end of the screw rod 6 , and a ball shaft ring 15 is provided on the connecting plate 13 . One end of the ball shaft ring 15 is fixed to the connecting plate 13 , and the other end is fixedly connected to the knife cylinder 3 . The rotational connection between the screw rod 6 and the cutter drum 3 in this embodiment is achieved through a ball shaft ring 15. A connecting plate 13 is fixed at one end of the screw rod 6. The connecting plate 13 is sleeved on the screw rod 6. One end of the screw rod 6 is a stepped rod. The end face of the connecting plate 13 abuts against the step of the step. A thread is provided on the small diameter rod of the stepped rod of the screw rod 6, and the connecting plate 13 is fixed to the screw rod 6 by threaded connection with a fixing nut 14. One end of the ball shaft ring 15 is fixed to the connecting plate 13 by a bolt. A flange connection structure is provided at one end of the cutter drum 3, and the cutter drum 3 is connected to the other end of the ball shaft ring 15 through a flange. In this way, the cutter drum 3 is rotationally connected to the screw rod 6, and the cutter drum 3 is driven to rotate together during the drilling process of the screw rod 6. After the cutter drum 3 enters the mining layer, the friction force does not drive the cutter drum 3 to rotate during the rotation of the screw rod 6.

[0032] Furthermore, the cutter barrel 3 includes a support barrel 32 and a storage barrel 31. The diameter of the storage barrel 31 is larger than that of the support barrel 32. The storage barrel 31 and the support barrel 32 are connected at a conical connection. The storage barrel 31 is connected to the ball bearing collar 15. In this embodiment, the inner diameter of the support barrel 32 is slightly larger than the outer diameter of the rotary cutter 2. The drilled product is transported by the spiral blade 22 to the storage barrel 31 for storage. In this embodiment, an opening is provided in the storage barrel 31 to allow the drilled water to flow out during simulated mining. The conical connection between the storage barrel 31 and the support barrel 32 facilitates the movement of the cutter barrel 3 along the wellbore.

[0033] Furthermore, a laser displacement sensor 11 is provided on the connecting rod 10. In this embodiment, a laser displacement sensor 11 is provided on the connecting rod 10 to detect the drilling distance.

[0034] The above description is merely a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Any person skilled in the art can, without departing from the scope of the technical solution of the present invention, make many possible changes and modifications to the technical solution of the present invention using the above technical content, or modify it into an equivalent embodiment with equivalent changes. Therefore, any changes, modifications, equivalent changes, and modifications made to the above embodiments based on the technology of the present invention without departing from the content of the technical solution of the present invention shall fall within the scope of protection of the present technical solution.

Claims

1. A drilling device for a high-gravity field natural gas hydrate simulation mining test, characterized by: The drilling device is installed on a high-speed rotating centrifuge and is used to make the entire device work in a hypergravity field. The drilling device includes a high-pressure model box (1), the high-pressure model box (1) is filled with high-pressure liquid to simulate a deep-sea environment, a bracket is provided on the outside of the high-pressure model box (1), a driving device is slidably provided on the bracket, a rotary cutter (2) is provided at the output end of the driving device, and the rotary cutter (2) is located in the high-pressure model box (1). During the operation of the centrifuge, the direction of the centrifugal force is consistent with the drilling direction of the rotary cutter (2); The bracket comprises a connecting rod (10) and two guide rods (5), the two guide rods (5) are arranged in parallel and one end of each is fixed to the high-pressure model box (1), and the other ends of the two guide rods (5) are connected via the connecting rod (10); The driving device includes a driving motor (9) and a screw (6), the driving motor (9) is fixed on a mounting plate (7), the mounting plate (7) and the two guide rods (5) are slidably connected via linear bearings (8), the screw (6) is connected to the output shaft of the driving motor (9), the rotary cutter (2) is fixed to one end of the screw (6), a nut (4) is fixed on the high-pressure model box (1), and the screw (6) is threadedly connected to the nut (4); The high-pressure model box (1) is provided with a mounting hole, the screw rod (6) extends through the mounting hole into the high-pressure model box (1), a composite seal (12) is provided on the inner side of the high-pressure model box (1) at the mounting hole, and the composite seal (12) is fixed on the high-pressure model box (1) for sealing the high-pressure model box (1) and the screw rod (6); A knife barrel (3) is sleeved on the outer side of one end of the rotary knife (2) connected to the screw rod (6), and the knife barrel (3) is rotatably mounted on the screw rod (6); A connecting plate (13) is provided at one end of the screw rod (6), a ball shaft ring (15) is provided on the connecting plate (13), one end of the ball shaft ring (15) is fixed to the connecting plate (13), and the other end is fixedly connected to the knife cylinder (3); The knife cylinder (3) comprises a supporting cylinder (32) and a material storage cylinder (31); the diameter of the material storage cylinder (31) is larger than the diameter of the supporting cylinder (32); the material storage cylinder (31) is connected to the supporting cylinder (32); the connecting portion is a conical structure; the material storage cylinder (31) is connected to the ball shaft ring (15); The rotary cutter (2) comprises a cutter bar (21) and a spiral blade (22), wherein the spiral blade (22) is spirally fixed to the cutter bar (21), and a cutting edge is provided at an edge of one end of the spiral blade (22) and at an end of the cutter bar (21), and a fixing seat (23) is provided at one end of the cutter bar (21), and a fixing hole is provided on the fixing seat (23) for mounting the rotary cutter (2).

2. The drilling device for high-gravity field natural gas hydrate simulation mining test according to claim 1, characterized in that: A laser displacement sensor (11) is provided on the connecting rod (10).

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