WELL DRILLING DEVICE FOR UNDERSEA IN-SITU EXPLOITATION OF NATURAL GAS HYDRATE

Abstract

A well drilling device for undersea in-situ exploitation of a natural gas hydrate is provided. The well drilling device includes a well drilling module, wherein the well drilling module includes a frame, a portal framed lead rail and a manipulator are mounted in the frame, a lower hydraulic tong is mounted at the bottom of the frame, an upper hydraulic tong is arranged coaxially above the lower hydraulic tong, and a coaxial space between the upper hydraulic tong and the lower hydraulic tong is a drilling column placement position; the upper hydraulic tong is mounted in a top drive, and the top drive is assembled in the portal framed lead rail to move vertically in a vertical direction of the portal framed lead rail; and a pipe rack is arranged in a rotation range of the manipulator, and is configured to store and place a drilling column.

Claims

1. A well drilling device for undersea in-situ exploitation of a natural gas hydrate, comprising: a well drilling module, wherein the well drilling module comprises a frame, wherein a portal framed lead rail and a manipulator are mounted in the frame, a lower hydraulic tong is mounted at a bottom of the frame, an upper hydraulic tong is arranged coaxially above the lower hydraulic tong, and a coaxial space between the upper hydraulic tong and the lower hydraulic tong is a drilling column placement position; the upper hydraulic tong is mounted in a top drive, and the top drive is assembled in the portal framed lead rail to move vertically in a vertical direction of the portal framed lead rail; and a pipe rack is arranged in a rotation range of the manipulator, the pipe rack is configured to store and place a drilling column, and the manipulator is configured to grab the drilling column to a position between the upper hydraulic tong and the lower hydraulic tong.

2. The well drilling device for the undersea in-situ exploitation of the natural gas hydrate according to claim 1, wherein the pipe rack is a disc-type pipe rack; and the manipulator reciprocates between the drilling column placement position and the disc-type pipe rack in a rotating manner to complete transferring and discharge of the drilling column.

3. The well drilling device for the undersea in-situ exploitation of the natural gas hydrate according to claim 1, wherein when the drilling column with a drilling bit is transferred to the drilling column placement position by the manipulator, the upper hydraulic tong tightly clamps, and the lower hydraulic tong opens; and the top drive moves down, the lower hydraulic tong tightly clamps, the upper hydraulic tong opens, the top drive moves down and is buckled in a rotating manner, and the lower hydraulic tong opens to complete drilling-in of a first drilling column.

4. The well drilling device for the undersea in-situ exploitation of the natural gas hydrate according to claim 3, wherein after the drilling-in of the first drilling column is completed, the lower hydraulic tong tightly clamps, the top drive is unbuckled and moves up, after a subsequent drilling column is transferred to the drilling column placement position by the manipulator, the upper hydraulic tong tightly clamps, the top drive moves down, and rotating connection buckled at a top of a well, the upper hydraulic tong opens, the top drive moves down and is buckled in the rotating manner, and the lower hydraulic tong opens to complete continuous drilling-in of the drilling columns.

5. The well drilling device for the undersea in-situ exploitation of the natural gas hydrate according to claim 1, wherein the drilling column adopts well drilling with a casing, and a down-hole drilling column combination of the well drilling with the casing comprises a drilling bit having a diameter smaller than an inner diameter of the casing and a reamer configured for passing through the inner diameter of the casing and enlarging a size of a borehole to be equal to a size of the casing.

6. The well drilling device for the undersea in-situ exploitation of the natural gas hydrate according to claim 1, wherein toothed bars are provided on two sides of the portal framed lead rail in the vertical direction; the top drive comprises a lifting and lowering motor and a rotating motor; the lifting and lowering motor is mounted in the toothed bars to allow the toothed bars to move vertically; and the rotating motor is connected to the upper hydraulic tong to drive the drilling column to rotate.

7. The well drilling device for the undersea in-situ exploitation of the natural gas hydrate according to claim 1, wherein four legs are further mounted at bottom four sides of the frame, and are all driven by independent hydraulic motors to extend outwards.

8. The well drilling device for the undersea in-situ exploitation of the natural gas hydrate according to claim 1, wherein the manipulator adopts an stand-column-type structure, the stand-column-type structure comprises a stand column, wherein an upper clamping tong and a lower clamping tong are arranged on the stand column, have both a clamping function and an extending and retracting function, and are configured for acting synchronously to meet a requirement of clamping the drilling column; the stand column is configured for rotating and lifting and lowering around a central axis of the stand column, so that the drilling column is transferred repeatedly between different positions; clamping and extending and retracting of the upper clamping tong and the lower clamping tong as well as lifting and lowering of the stand column are all driven by a hydraulic cylinder; slewing of the stand column is driven by a hydraulic motor.

9. The well drilling device for the undersea in-situ exploitation of the natural gas hydrate according to claim 2, wherein the disc-type pipe rack is provided in a double/multi-layer arrangement, and after a drilling column on an outer layer is taken out, a drilling column on an inner layer is allowed for automatically shifting to the outer layer; and the disc-type pipe rack is configured for rotating around a central axis of the disc-type pipe rack and is driven by a hydraulic motor.

10. The well drilling device for the undersea in-situ exploitation of the natural gas hydrate according to claim 1, further comprising: a seawater circulation system, wherein the seawater circulation system is configured to circulate seawater and comprises an undersea pump, a hose, and a joint; and the undersea pump is mounted on a frame structure of an undersea well drilling completion apparatus body, and is driven by a hydraulic motor, and cuttings circulating from seafloor to a wellhead are transported to a seabed at a predetermined distance from the wellhead through the hose.

11. The well drilling device for the undersea in-situ exploitation of the natural gas hydrate according to claim 2, wherein when the drilling column with a drilling bit is transferred to the drilling column placement position by the manipulator, the upper hydraulic tong tightly clamps, and the lower hydraulic tong opens; and the top drive moves down, the lower hydraulic tong tightly clamps, the upper hydraulic tong opens, the top drive moves down and is buckled in the rotating manner, and the lower hydraulic tong opens to complete drilling-in of a first drilling column.

12. The well drilling device for the undersea in-situ exploitation of the natural gas hydrate according to claim 11, wherein after the drilling-in of the first drilling column is completed, the lower hydraulic tong tightly clamps, the top drive is unbuckled and moves up, after a subsequent drilling column is transferred to the drilling column placement position by the manipulator, the upper hydraulic tong tightly clamps, the top drive moves down, and rotating connection buckled at a top of a well, the upper hydraulic tong opens, the top drive moves down and is buckled in the rotating manner, and the lower hydraulic tong opens to complete continuous drilling-in of the drilling columns.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0023] FIG. 1 is a schematic diagram of an overall structure of a well drilling module of a well drilling device for undersea in-situ exploitation of a natural gas hydrate provided by an embodiment of the present invention;

[0024] FIG. 2 is a schematic arrangement diagram of a manipulator;

[0025] FIGS. 3A-3F show a flow chart of transferring, loading and unloading, and drilling-in operations of a drilling column;

[0026] FIG. 4 is a top view of a well drilling device for undersea in-situ exploitation of a natural gas hydrate provided by an embodiment of the present invention;

[0027] FIG. 5 is a schematic diagram of states of a leveling leg;

[0028] FIG. 6 is a schematic diagram of a pipe rack without a drilling column;

[0029] FIG. 7 is a schematic structural diagram of a manipulator;

[0030] FIG. 8 is a schematic structural diagram of a top drive;

[0031] FIG. 9 is a schematic structural diagram of an upper hydraulic tong and a lower hydraulic tong; and

[0032] Reference numerals: 1, frame; 2, portal framed lead rail; 3, manipulator; 4, lower hydraulic tong; 5, upper hydraulic tong; 6, top drive; 7, leveling leg; 8, pipe rack; 31, stand column; 32, upper clamping tong; 33, lower clamping tong; 61, lifting and lowering motor; 62, rotating motor; and 100, drilling column.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Embodiments

[0033] The followings will further describe the technical solutions of the present invention with reference to the accompanying drawings and embodiments.

[0034] Referring to FIG. 1, a well drilling device for undersea in-situ exploitation of a natural gas hydrate provided by the present embodiment mainly includes a well drilling module. The well drilling module includes a frame 1. A portal framed lead rail 2 and a manipulator 3 are mounted in the frame 1, a lower hydraulic tong 4 is mounted at the bottom of the frame 1, an upper hydraulic tong 5 is arranged coaxially above the lower hydraulic tong 4, and a coaxial space between the upper hydraulic tong 5 and the lower hydraulic tong 4 is a drilling column 100 placement position, namely, the center position of a wellhead. The upper hydraulic tong 5 is connected to a central pipe of a top drive 6, and rotates along with the central pipe. The top drive 6 is assembled in the portal framed lead rail 2 to move vertically in the vertical direction of the portal framed lead rail 2. A pipe rack 8 is arranged in a rotation range of the manipulator 3, and is configured to store and place a drilling column 100. The manipulator 3 is configured to grab the drilling column 100 to the position between the upper hydraulic tong 5 and the lower hydraulic tong 4. In this way, as shown in FIG. 2, the loading and unloading of the drilling column 100 are completed using the top drive 6, the upper hydraulic tong 5 and the lower hydraulic tong 4 together, and the manipulator 3 is configured to transfer a single drilling column 100 between a wellhead center and the pipe rack 8, and is arranged between the wellhead center and the pipe rack 8. Therefore, less equipment arranged at the wellhead and occupies less space, so that the space of the whole undersea in-situ well drilling completion apparatus is compact.

[0035] As shown in FIGS. 3A-3F, when the drilling column 100 with a drilling bit is transferred to the drilling column 100 placement position by the manipulator 3, as shown in FIG. 3A, the upper hydraulic tong 5 tightly clamps and the lower hydraulic tong 4 opens. Then, as shown in FIG. 3B, the top drive 6 moves down, the lower hydraulic tong 4 tightly clamps, the upper hydraulic tong 5 opens, and the top drive 6 moves down and is buckled in rotating manner. Then, as shown in FIG. 3C, the lower hydraulic tong 4 opens, the top drive 6 drills in, the lower hydraulic tong 4 tightly clamps, and the top drive 6 is unbuckled to complete the drilling-in of the first drilling column. After the drilling-in of the first drilling column is completed, as shown in FIG. 3D, the top drive 6 moves up, and the manipulator 3 transfers the second drilling column to the wellhead center. As shown in FIG. 3E, the top drive 6 moves down, the upper hydraulic tong 5 tightly clamps, and the top drive 6 moves down, and rotating connection buckled at the top of the well. As shown in FIG. 3F, the upper hydraulic tong 5 opens, the top drive 6 moves down, and rotating connection buckled at the upper part, and the lower hydraulic tong 4 opens to wait for a next drilling column 100 to be transferred. In this way, the flow of transferring, loading and unloading, and drilling-in operations of the drilling columns 100 can be achieved.

[0036] As a preference of the present embodiment, as shown in FIG. 4, leveling legs 7 are further mounted at the bottom four sides of the frame 1, and are all driven by independent hydraulic motors to extend outwards. As shown in FIG. 5, the leveling leg 7 is driven by an oil cylinder to extend outwards, has a large adjustment range, and can greatly expand a grounding area to increase stability to play the role of leveling chassis and stable support. In this way, during a process that the well drilling device for the undersea in-situ exploitation of the natural gas hydrate is launched to the undersea, the supporting and self-leveling of the well drilling device are achieved through the four legs with adjustable power, so as to avoid lateral slip or posture change of the well drilling device itself in subsequent actions.

[0037] In a specific embodiment, as shown in FIG. 6, the pipe rack 8 is a disc-shaped pipe rack and is provided with two or more. The manipulator 3 reciprocates between the drilling column 100 placement position and the disc-type pipe racks in a rotating manner to complete the transferring of the drilling column 100. In this way, by arranging the manipulator 3 between the two disc-shaped pipe racks 8 and in the center of the whole device, a requirement of repeated transmitting of the drilling columns 100 between the two pipe racks 8 and the wellhead center can be met, which simplifies the structure of an undersea drilling rig. As shown in FIGS. 3A-3F, the disc-type pipe rack adopts a double-layer arrangement of the drilling columns 100, and the drilling columns 100 between layers are closely attached. After a drilling column 100 on the outer layer is taken out, a drilling column 100 on the inner layer can automatically shift to the outer layer. The pipe rack can rotate around its central axis and is driven by a hydraulic motor. In this way, the automatic discharge of the drilling column 100 can be achieved. The upper hydraulic tong 5 and the lower hydraulic tong 4 have the same structural form. Three hydraulic cylinders are used to clamp the drilling column 100, and are evenly distributed on the same plane at angles of 120. In addition, a synchronous movement mechanism is provided to meet a centering requirement when the drilling column 100 is clamped. In this way, the automatic loading and unloading of the drilling column 100 can be achieved.

[0038] In a specific embodiment, as shown in FIG. 7, the manipulator 3 adopts an stand-column-type structure, including a stand column 31. The upper clamping tong 32 and the lower clamping tong 33 are arranged on the stand column 31, have both a clamping function and an extending and retracting function, and can synchronously act to meet a requirement of clamping the drilling column 100. The stand column 31 can rotate and lift and lower around its own central axis, so that the drilling column 100 is transferred repeatedly between different positions. The clamping and the extending and retracting of the upper clamping tong 32 and the lower clamping tong 33 are all driven by hydraulic cylinders. The slewing of the stand column 31 is driven by a hydraulic motor.

[0039] In a specific embodiment, the drilling column 100 adopts well drilling with a casing, and a down-hole drilling column 100 combination of the well drilling with the casing consists of a drilling bit having a diameter smaller than an inner diameter of the casing and a reamer capable of passing through the inner diameter of the casing and enlarging the size of a borehole to be the same as the size of the casing. In this way, the well drilling and the casing running are carried out simultaneously, so there is no risk that the casing cannot be run due to the collapse of a borehole wall. The casing has a large outer diameter, so that a small annular space is formed between the casing and the borehole wall; the lifting speed of cuttings is high; it is less liable to settlement; and the required displacement of the undersea pump is small.

[0040] In a specific embodiment, toothed bars are provided on two sides of the portal framed lead rail 2 in the vertical direction. As shown in FIG. 8, the top drive 6 includes a lifting and lowering motor 61 and a rotating motor 62. The lifting and lowering motor 61 is mounted in the toothed bars of the portal framed lead rail 2 to enable the toothed bars to move vertically. The rotating motor 62 is connected to the upper hydraulic tong 5 to drive the drilling column 100 to rotate. In other words, the top drive 6 is driven by the hydraulic motor to move vertically, achieves transmission by a pinion and rack, and has the advantages of a simple structure, stable transmission, convenient pressurization and easy control.

[0041] In a specific embodiment, as shown in FIG. 9, the upper hydraulic tong 5 and the lower hydraulic tong 4 have the same structural form. Three hydraulic cylinders are used to clamp the drilling column 100 and are evenly distributed on the same plane at angles of 120. In addition, a synchronous movement mechanism is provided to meet a centering requirement when the drilling column 100 is clamped.

[0042] As the preferred well drilling device for the undersea in-situ exploitation of the natural gas hydrate provided by the present embodiment, the device further includes a seawater circulation system. The seawater circulation system is configured to circulate seawater, plays the role of cooling the drilling bit and carrying cuttings, and consists of an undersea pump, a hose and a joint. The cuttings circulating from the seafloor to the wellhead are transported to the undersea at a certain distance from the wellhead through the hose.

[0043] As the further preferred well drilling device for the undersea in-situ exploitation of the natural gas hydrate provided by the present embodiment, a pipe storage module, an additional module, a well cementation module and a well completion module may be further connected around the well drilling module to achieve the completely automatic undersea exploitation.

[0044] In the specific application of the well drilling device for the undersea in-situ exploitation of the natural gas hydrate, the well drilling device is carried by a water surface support vessel with the ability of launching of a deep-water device to a target sea area, and is launched by a launching apparatus of the water surface support vessel; and the connection between the well drilling device and the water surface support vessel is established through an umbilical cable with the bearing ability, so that the well drilling device is transferred from the offshore platform to the undersea, thereby greatly accelerating the drilling speed and reducing the production cost. Meanwhile, the influence of marine climate conditions on the undersea in-situ well drilling is reduced, and obvious advantages and excellent feasibility are shown.

[0045] The above embodiments are only for illustrating the technical conception and features of the present invention, and their purpose is to enable those skilled in the art to understand the content of the present invention and to implement it accordingly, without limiting the protection scope of the present invention. Any equivalent changes or modifications made in accordance with the essence of the content of the present invention shall be included in the protection scope of the present invention.