Double tube

Abstract

The application provides a double tube which comprises an inner pipe column and an outer pipe column, the lower end of the inner pipe column is connected with a guide device, the lower end of the guide device is connected with a drill bit, the guide device can drive the drill bit to deflect by a preset angle, the inside of the inner pipe column is provided with a through flow channel for the circulation of a drilling circulating medium; a flexible outer pipe column is sleeved outside the inner pipe column, and an annular space for the circulation of the drilling circulating medium is formed between the flexible outer pipe column and the inner pipe column, the upper part of the guide device or the lower part of the inner pipe column is hinged with the lower part of the flexible outer pipe column. The double tube can drive the drill bit to deflect by a preset angle in a preset direction through the guide device under the condition of rotation, so as to change the wellbore trajectory and realize a short build-up rate; the flexible outer pipe column can well bear the axial pressure, so as to transmit the torque for driving the drill bit to rotate to the guide device, and thus the guided drilling with a certain wellbore extension length is realized.

Description

Technical Field

[0001] This invention relates to the fields of drilling technology and oil and gas extraction technology, and in particular to a double-pipe system. Background Technology

[0002] The exploration and development of underground material and spatial resources require extensive application of drilling technology. Existing directional drilling technologies mainly include downhole motor-guided drilling and rotary directional drilling. The maximum build-up rate achievable by these technologies is generally no more than 15° / 30 meters, and neither can achieve controlled-track short-radius directional drilling or continue directional drilling at the bottom of an existing short-radius well section. Furthermore, many existing radial or short-radius drilling techniques cannot effectively control the wellbore trajectory, resulting in poor performance for underground resource development and utilization. Summary of the Invention

[0003] The purpose of this invention is to provide a dual-tube system capable of directional drilling with a certain wellbore extension length.

[0004] To achieve the above objectives, the present invention provides a dual-tube comprising:

[0005] The inner tubing has a guide device connected to its lower end, and a drill bit is connected to the lower end of the guide device. The guide device can drive the drill bit to deflect at a preset angle. The inner tubing has a through flow channel for the circulation of drilling media inside.

[0006] A flexible outer tubing string is sleeved outside the inner tubing string, and an annular space for the circulation of drilling media is formed between the flexible outer tubing string and the inner tubing string. The upper part of the guide device or the lower part of the inner tubing string is hinged to the lower part of the flexible outer tubing string at a corresponding position.

[0007] As described above, in the double tube, the flexible outer tube column includes a plurality of outer connecting short sections that are hinged sequentially from top to bottom. Adjacent outer connecting short sections are connected by an outer hinge structure, and the lowermost outer connecting short section is connected to the guide device.

[0008] As described above, in the double tube configuration, multiple spaced-apart straightening devices are provided between the flexible outer tube and the inner tube.

[0009] In the double tube described above, the straightening device is a straightening bearing or a roller straightener.

[0010] The double tube as described above, wherein each of the outer connecting sections is provided with the straightening device between the inner tube column and the outer connecting section.

[0011] As described above, in the dual-tube configuration, the inner tube is either a pressure-bearing flexible tube or a rigid tube.

[0012] The double tube as described above, wherein a suspension device is connected between the inner tube column and the flexible outer tube column, and the suspension device is located at the upper part of the inner tube column.

[0013] The dual-tube configuration described above, wherein the guiding device is connected to the wellhead control endpoint via a jumper wire.

[0014] As described above, in the double tube configuration, the guiding device includes a drive shaft, a support body, and a sleeve arranged sequentially from the inside out. The upper end of the sleeve is hinged to the lower end of the flexible outer tube column, the upper end of the support body is connected to the lower end of the inner tube column, and the lower end of the drive shaft is connected to the drill bit. An annular movable space is provided between the drive shaft and the support body, and a deflection mechanism is provided within the annular movable space. The deflection mechanism can drive the drive shaft and the support body to move relative to each other.

[0015] As described above, in the double tube, the upper part of the sleeve is connected to the bearing body through a first hinge structure. The deflection mechanism includes at least three sets of drive hydraulic cylinders spaced apart circumferentially along the lower part of the bearing body. Each drive hydraulic cylinder includes a piston structure receiving cavity disposed in the outer wall of the bearing body and a drive piston structure disposed in the piston structure receiving cavity. The drive piston structure can drive the transmission shaft and the bearing body to move relative to each other.

[0016] As described above, in the dual-tube configuration, the deflection mechanism includes an eccentric ring and an electric actuator. The electric actuator is mounted on the support body, and the eccentric ring is positioned between the drive shaft and the support body. The lower part of the drive shaft is connected to the support body via a second hinge structure. The electric actuator can drive the eccentric ring to rotate, and the rotation of the eccentric ring can drive the drive shaft and the support body to move relative to each other. A first straightening structure is provided between the upper part of the support body and the sleeve, and a second straightening structure is provided between the lower part of the support body and the sleeve. The second hinge structure is located between the first straightening structure and the second straightening structure.

[0017] Compared with the prior art, the advantages of the present invention are as follows:

[0018] The dual tubing of this invention, by setting a guiding device, enables the drill bit to deflect at a preset angle in a preset direction under rotational conditions, thereby changing the wellbore trajectory and achieving a short build-up rate; by setting a flexible outer tubing string, it enables the torque used to drive the drill bit to rotate to be effectively transmitted to the guiding device under rotational conditions, thereby achieving guided drilling with a certain wellbore extension length. Attached Figure Description

[0019] The following figures are intended only to illustrate and explain the present invention and do not limit the scope of the invention. Wherein:

[0020] Figure 1 This is a schematic diagram of one structure of the double tube of the present invention;

[0021] Figure 2 This is another structural schematic diagram of the double tube of the present invention;

[0022] Figure 3 This is another structural schematic diagram of the double tube of the present invention.

[0023] Explanation of icon numbers:

[0024] 1. Inner tubing; 11. Through-flow channel; 111. Pressure-bearing hose; 112. Rigid tubing;

[0025] 2. Guide device; 21. Sleeve; 22. Bearing body; 23. Drive shaft; 24. First hinge structure; 25. Drive hydraulic cylinder; 26. Eccentric ring; 27. Electric drive actuator; 28. Second hinge structure; 291. First straightening structure; 292. Second straightening structure;

[0026] 3. Drill bit;

[0027] 4. Flexible outer tubular column; 41. External connecting short section; 42. External hinged structure;

[0028] 5. Circular space;

[0029] 6. Suspension device;

[0030] 7. Straightening device; 71. Straightening bearing; 72. Roller straightener;

[0031] 9. Jumper wire. Detailed Implementation

[0032] To provide a clearer understanding of the technical solution, objectives, and effects of the present invention, specific embodiments are now described in conjunction with the accompanying drawings. The use of adjective or adverbial modifiers such as "upper" and "lower," "inner" and "outer" is merely for facilitating relative reference between multiple sets of terms and does not describe any specific directional limitation on the modified terms. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, features defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of the present invention, unless otherwise stated, "a plurality of" means two or more.

[0033] like Figure 1 , Figure 2 and Figure 3 As shown, the present invention provides a dual-tube system comprising an inner tube column 1 and a flexible outer tube column 4, wherein:

[0034] The lower end of the inner tubing string 1 is connected to a guide device 2, and the lower end of the guide device 2 is connected to a drill bit 3. The guide device 2 can drive the drill bit 3 to deflect at a preset angle, that is, the guide device 2 can drive the drill bit 3 to deflect at a preset angle in a preset direction, thereby changing the wellbore trajectory to achieve a short build-up rate. The inner tubing string 1 is provided with a through flow channel 11 for the circulation of drilling circulating medium. The drilling circulating medium can flow to the drill bit 3 through the through flow channel 11 to drive the drill bit 3 to perform drilling operations. The specific structure and working principle of the drill bit 3 are existing technologies and will not be described in detail here.

[0035] The flexible outer tubing string 4 is sleeved outside the inner tubing string 1, and an annular space 5 is formed between the flexible outer tubing string 4 and the inner tubing string 1 for the circulation of drilling circulating medium. The drilling circulating medium can return to the wellhead from the annular space 5. The upper part of the guide device 2 or the lower part of the inner tubing string 1 is hinged to the corresponding lower part of the flexible outer tubing string 4, so that the flexible outer tubing string 4 can transmit drilling torque to the guide device 2 and also protect the inner tubing string 1.

[0036] The dual tubing of the present invention, by setting a guide device 2, enables the drill bit 3 to deflect at a preset angle in a preset direction under rotational conditions, thereby changing the wellbore trajectory and achieving a short build-up rate; by setting a flexible outer tubing string 4, the torque used to drive the drill bit 3 to rotate can be effectively transmitted to the guide device 2 under rotational conditions, thereby achieving guided drilling with a certain wellbore extension length.

[0037] Furthermore, such as Figure 1 , Figure 2 and Figure 3 As shown, the flexible outer tube column 4 includes multiple external connecting short sections 41 that are hinged sequentially from top to bottom. Adjacent external connecting short sections 41 are connected by an external hinge structure 42. The lowermost external connecting short section 41 is connected to the upper end of the guide device 2. That is, the flexible outer tube column 4 has a hinge structure. Since the flexible outer tube column 4 has a large diameter, in order to meet the requirements of skewness, the hinge method is adopted to maximize the flexibility of the flexible outer tube column 4. The external hinge structure 42 can be the universal joint and sleeve 21 matching structure in the prior art, or the ball seat and ball head matching structure in the prior art, which will not be described in detail here.

[0038] Of course, the flexible outer tube 4 can also be a slotted tube, and to ensure the sealing of the annular space 5, the slots in the slotted tube are filled with sealing material.

[0039] Furthermore, the inner tubing string 1 is either a pressure-bearing hose 111 or a rigid tubing string 112. When in use, the pressure-bearing hose 111 or the rigid tubing string 112 can be selected as the inner tubing string 1 according to the trajectory of the drilled well.

[0040] Furthermore, such as Figure 1 , Figure 2 and Figure 3 As shown, multiple centering devices 7 are provided between the flexible outer tubing string 4 and the inner tubing string 1 at intervals. The centering devices 7 can maintain an annular space 5 between the inner tubing string 1 and the flexible outer tubing string 4 to ensure that the circulating medium can flow from the inside of the inner tubing string 1 to the drill bit 3, and then return to the wellhead from the annular space 5 between the inner tubing string 1 and the flexible outer tubing string 4.

[0041] Furthermore, each external connecting section 41 is provided with a straightening device 7 between it and the inner tubing 1 to prevent buckling or twisting between the external connecting sections 41, which would hinder the transmission of drilling torque and thus enable the drilling torque to be transmitted smoothly.

[0042] Furthermore, such as Figure 1 and Figure 2 As shown, the centralizing device 7 is a centralizing bearing 71 or a roller centralizer 72. Specifically, both the centralizing bearing 71 and the roller centralizer 72 can enable the inner tubing 1 to rotate relative to the flexible outer tubing 4, so as to transmit drilling power during the insertion into mud or other rheological formations. Preferably, the roller centralizer 72 can also play a supporting role.

[0043] Furthermore, such as Figure 2 As shown, a suspension device 6 is connected between the inner tube column 1 and the flexible outer tube column 4, and the suspension device 6 is located on the upper part of the inner tube column 1. Specifically, when the inner tube column 1 is a rigid tube column 112, the suspension device 6 includes a thrust bearing and a centering bearing 71, or a composite bearing that has both centering and thrust functions, so that the inner tube column 1 and the flexible outer tube column 4 do not move axially, and at the same time, it does not hinder the inner tube column 1 from rotating inside the flexible outer tube column 4.

[0044] Furthermore, such as Figure 1 , Figure 2 and Figure 3 As shown, the guide device 2 is connected to the wellhead control terminal via the jumper wire 9. The wellhead control terminal can issue control commands to the guide device 2. In addition, the wellhead control terminal can also supply power to the guide device 2 to avoid the additional costs and power outage risks associated with downhole power generation.

[0045] Furthermore, such as Figure 1 , Figure 2 and Figure 3As shown, the guiding device 2 includes a drive shaft 23, a bearing body 22, and a sleeve 21 arranged sequentially from the inside to the outside. The upper end of the sleeve 21 is hinged to the lower end of the flexible outer tubing 4. The upper end of the bearing body 22 is connected to the lower end of the inner tubing 1. The lower end of the drive shaft 23 is connected to the drill bit 3. An annular movable space is provided between the drive shaft 23 and the bearing body 22. A deflection mechanism is provided in the annular movable space. The deflection mechanism can drive the drive shaft 23 and the bearing body 22 to move relative to each other, so as to drive the drill bit 3 to deflect at a preset angle in a preset direction, thereby changing the wellbore trajectory and achieving a short build-up rate.

[0046] In one embodiment of the present invention, such as Figure 1 and Figure 2 As shown, the upper part of the sleeve 21 is connected to the bearing body 22 through the first hinge structure 24. The deflection mechanism includes at least three sets of drive hydraulic cylinders 25 spaced apart along the lower circumference of the bearing body 22. Preferably, each drive hydraulic cylinder 25 is evenly arranged along the circumference of the bearing body 22. The drive hydraulic cylinder 25 includes a piston structure accommodating cavity disposed in the outer wall of the bearing body 22 and a drive piston structure disposed in the piston structure accommodating cavity. The drive piston structure can drive the transmission shaft 23 and the bearing body 22 to move relative to each other, so that the drill bit 3 at the lower end of the bearing body 22 laterally cuts the formation in a symmetrical orientation.

[0047] In another embodiment of the invention, such as Figure 3 The deflection mechanism shown includes an eccentric ring 26 and an electric actuator 27. The electric actuator 27 is mounted on the support body 22, and the eccentric ring 26 is positioned between the drive shaft 23 and the support body 22. The lower part of the drive shaft 23 is connected to the support body 22 via a second hinge structure 28. The electric actuator 27 can drive the eccentric ring 26 to rotate, and the rotation of the eccentric ring 26 can drive the drive shaft 23 and the support body 22 to move relative to each other. Specifically, the electric actuator is a drive motor, which can drive the eccentric ring 26 to rotate. The rotation of 26 can drive the transmission shaft 23 to swing around the second hinge structure 28 and / or rotate around the axis of the bearing body 22; a first straightening structure 291 is provided between the upper part of the bearing body 22 and the sleeve 21, and a second straightening structure 292 is provided between the lower part of the bearing body 22 and the sleeve 21. The second hinge structure 28 is located between the first straightening structure 291 and the second straightening structure 292. The first straightening structure 291 and the second straightening structure 292 can ensure that the controllable flexible drilling pressure torque transmission string and the wellbore always remain coaxial.

[0048] It should be noted that the specific working principle of the above-mentioned deflection mechanism is existing technology and will not be elaborated here. Of course, the deflection mechanism can also adopt any existing structure that can drive the drill bit to deflect at a preset angle in a preset direction.

[0049] In summary, the dual tubing of the present invention, by setting a guiding device, enables the drill bit to deflect at a preset angle in a preset direction under rotational conditions, thereby changing the wellbore trajectory and achieving a short build-up rate; by setting a flexible outer tubing string, it enables the torque used to drive the drill bit to rotate to be effectively transmitted to the guiding device under rotational conditions, thereby achieving guided drilling with a certain wellbore extension length.

[0050] The above description is merely an illustrative embodiment of the present invention and is not intended to limit the scope of the invention. Any equivalent changes and modifications made by those skilled in the art without departing from the concept and principles of the present invention should fall within the scope of protection of the present invention. Furthermore, it should be noted that the components of the present invention are not limited to the overall application described above. Each technical feature described in the specification can be used individually or in combination as needed. Therefore, the present invention naturally covers other combinations and specific applications related to the inventive points of this case.

Claims

1. A double tube characterized in that, The double tube comprises: an inner pipe column, a lower end of which is connected with a guiding device, a lower end of the guiding device is connected with a drill bit, the guiding device can drive the drill bit to deflect a preset angle, an inside of the inner pipe column is provided with a through flow channel for circulation of a drilling circulating medium; a flexible outer pipe column, which is sleeved on an outside of the inner pipe column, and an annular space for circulation of the drilling circulating medium is formed between the flexible outer pipe column and the inner pipe column, an upper portion of the guiding device or a lower portion of the inner pipe column is hingedly connected with a lower portion of the flexible outer pipe column.

2. The double tube according to claim 1, wherein the flexible outer pipe column comprises a plurality of outer connecting short pipes which are hingedly connected in sequence from top to bottom, two adjacent outer connecting short pipes are connected through an outer hinge structure, and a lowermost outer connecting short pipe is connected with the guiding device.

3. The double tube according to claim 2, wherein a plurality of spacing arranged centralizing devices are arranged between the flexible outer pipe column and the inner pipe column.

4. The double tube according to claim 3, wherein the centralizing device is a centralizing bearing or a roller centralizer.

5. The double tube according to claim 3, wherein the centralizing device is arranged between each outer connecting short pipe and the inner pipe column.

6. The double tube according to claim 1, wherein the inner pipe column is a pressure-bearing flexible pipe or a rigid pipe column.

7. The double tube according to claim 1, wherein a suspension device is connected between the inner pipe column and the flexible outer pipe column, and the suspension device is arranged at an upper portion of the inner pipe column.

8. The double tube according to claim 1, wherein the guiding device is connected with a wellhead control terminal through a jumper.

9. The double tube according to any one of claims 1 to 8, wherein the guiding device comprises a transmission shaft, a bearing body and a sleeve which are sleeved in sequence from inside to outside, an upper end of the sleeve is hingedly connected with a lower end of the flexible outer pipe column, an upper end of the bearing body is connected with a lower end of the inner pipe column, a lower end of the transmission shaft is connected with the drill bit, an annular movable space is arranged between the transmission shaft and the bearing body, a deflection mechanism is arranged in the annular movable space, and the deflection mechanism can drive the transmission shaft and the bearing body to move relative to each other.

10. The double tube according to claim 9, wherein a first hinge structure is arranged between an upper portion of the sleeve and the bearing body, the deflection mechanism comprises at least three groups of driving hydraulic cylinders which are arranged in a circumferential direction at a lower portion of the bearing body, each driving hydraulic cylinder comprises a piston structure accommodating cavity arranged in an outer wall of the bearing body and a driving piston structure arranged in the piston structure accommodating cavity, and the driving piston structure can drive the transmission shaft and the bearing body to move relative to each other.

11. The double tube according to claim 9, wherein The deflection mechanism comprises an eccentric ring and an electric driving executor, the electric driving executor is arranged on the bearing body, the eccentric ring is arranged between the transmission shaft and the bearing body, the lower part of the transmission shaft and the bearing body are connected through a second hinged structure, the electric driving executor can drive the eccentric ring to rotate, the rotation of the eccentric ring can drive the relative movement of the transmission shaft and the bearing body, the upper part of the bearing body and the sleeve are provided with a first centralizing structure, the lower part of the bearing body and the sleeve are provided with a second centralizing structure, and the second hinged structure is located between the first centralizing structure and the second centralizing structure.

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