Single-cylinder double-well construction equipment and construction method

Abstract

The application discloses a single-cylinder double-well construction equipment and a construction method. The construction equipment comprises a water isolation guide pipe, a Y-shaped guide head is connected to the lower end of the water isolation guide pipe; the water isolation guide pipe is connected by a plurality of water isolation guide pipe bodies, a space partition plate body is arranged in the water isolation guide pipe body, the space partition plate body divides the water isolation guide pipe body into two spaces, and casing A and casing B are arranged in the two spaces respectively; a Y-shaped flow channel is formed in the Y-shaped guide head, a flat sealing surface is formed in one branch flow channel of the Y-shaped flow channel, the sealing surface is in contact with the bottom end of the casing B, a one-way valve A is arranged in the other branch flow channel, and a one-way valve B is arranged in the main flow channel. The single-cylinder double-well water isolation guide pipe is used in cooperation, a single-cylinder space is divided into two wellbores, well cementation operation is carried out through the Y-shaped guide head, the casing A and the casing B, a complete single-cylinder double-well system is formed, and the next construction operation is facilitated.

Description

Technical Field

[0001] This invention relates to the field of oil and gas field drilling technology, and in particular to a single-tube dual-well construction equipment and construction method. Background Technology

[0002] Currently, the number of offshore oilfield drillings is increasing year by year, but offshore slot resources are limited, and platform construction requires huge investments, which is not conducive to economic development. The single-tube dual-well technology, which utilizes one slot to develop two wells, allows for drilling more wells on the limited space of offshore platform jackets, reducing drilling costs and engineering expenses. Therefore, the single-tube dual-well technology is a good solution for the efficient and rational use of slot resources. Early single-tube dual-well drilling technology used a dual-wellhead system to divide the main wellbore into multiple branch wellbores. This process has many drawbacks, such as easy snagging during casing string installation, excessive cementing slurry consumption, high instantaneous flow requirements leading to formation leakage, and difficulty in directional drilling. Therefore, it is of great significance to provide a single-tube dual-well construction equipment and method that can effectively solve the shortcomings of the current process and is simple, safe, and reliable. Summary of the Invention

[0003] In order to solve the above-mentioned technical problems, the present invention provides a single-tube dual-well construction equipment and construction method.

[0004] Firstly, this application provides a single-tube dual-well construction device, which is achieved by the following technical solution.

[0005] A single-tube dual-well construction device includes a riser pipe with a Y-shaped guide head connected to its lower end. The riser pipe is composed of multiple sections connected together. The riser pipe body has an internal space-dividing plate that divides the interior into two spaces, into which casing A and casing B are respectively inserted. The Y-shaped guide head forms a Y-shaped flow channel. One branch flow channel has a flat sealing surface that contacts the bottom end of casing B. A one-way valve A is located in the other branch flow channel, and a one-way valve B is located in the main flow channel.

[0006] Furthermore, the water-proof conduit body includes an upper connector, a pipe body, and a lower connector connected in sequence.

[0007] Furthermore, the upper part of the upper connector is provided with a radial limiting groove and a clamping screw hole; the lower part of the lower connector is provided with an axial limiting groove and a fixing pin hole; the radial limiting groove matches the fixing pin hole and a fixing pin passes through it, and the clamping screw hole matches the axial limiting groove and a clamping screw passes through it.

[0008] Furthermore, both ends of the space-dividing plate are provided with sealing rubber.

[0009] Furthermore, the upper part of the Y-shaped guide head is provided with a radial limiting groove and a clamping screw hole.

[0010] Furthermore, the lower part of the casing A is connected to a drillable blind plug.

[0011] Furthermore, the lower part of the sleeve B is vulcanized with a sealing rubber sleeve.

[0012] Furthermore, the one-way valve A causes the fluid to flow upward from the lower part of the Y-shaped guide head, and the one-way valve B causes the fluid to flow downward from the upper part of the Y-shaped guide head.

[0013] Secondly, this application provides a single-tube dual-well construction method, which is achieved by the following technical solution.

[0014] A single-tube dual-well construction method includes the following steps:

[0015] S1. Before connecting the water-proof conduit, the space partition plate is pre-installed inside the water-proof conduit body, and the sealing rubber is installed at the upper and lower ends of the space partition plate.

[0016] S2. When connecting the water-proof conduit, insert the upper and lower connectors of the water-proof conduit into the fit, rotate the water-proof conduit to align the upper and lower connector limiting grooves, install the fixing pins and clamping screws to limit the axial and circumferential movement; at the same time, the sealing rubber at the bottom of the space partition plate and the sealing rubber at the top of another space partition plate make an interference fit to achieve the sealing function.

[0017] S3. The connection method between the Y-type guide head and the water-proof guide pipe is the same as in step S2; after the overall installation, the inside of the water-proof guide pipe will be divided into two spaces, namely wellbore A and wellbore B;

[0018] S4. When the drill bit drills the underwater soil to a certain depth, the Y-type guide head and the water-proof guide pipe are sequentially lowered to the predetermined depth according to the installation steps. Then, the casing A is lowered into the well A. After the casing A is lowered to contact the guide head, it is lifted up, leaving a gap between the drillable blind plug and the Y-type guide head.

[0019] S5. Run casing B into wellbore B. After casing B is in place, press it down so that the sealing rubber sleeve is inserted into the sealing surface of the guide head.

[0020] S6. After casing A and casing B are lowered into place, cementing operations begin. Cement slurry is injected from casing B, flows through flow channel II, through check valve A, check valve B, flow channel I, and flow channel III, and the cement slurry in the main wellbore and wellbore A rises back to the mud surface. Then casing B is pulled up.

[0021] S7. After the mud in the main wellbore and wellbore A has solidified, cement slurry is injected through casing B. The cement slurry rises back up in wellbore B and waits for it to solidify after reaching the mud surface. Casing A, casing B, riser, and main wellbore are cemented together to form an integrated system, completing the single-tube double-well construction operation.

[0022] This application has the following beneficial effects.

[0023] This invention uses multiple single-tube double-well riser pipes in combination to divide the single-tube space into two wells, and performs cementing operations through a Y-shaped guide head, casing A, and casing B to form a complete single-tube double-well system, which facilitates subsequent construction operations. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the structure of the single-cylinder double-well water-proof guide pipe of the present invention;

[0025] Figure 2 This is a cross-sectional schematic diagram of the single-cylinder double-well water-proof guide pipe of the present invention;

[0026] Figure 3 This is a schematic diagram intended to illustrate the sealing rubber of the present invention;

[0027] Figure 4 This is a schematic diagram of the structure of the connector of the present invention;

[0028] Figure 5 This is a schematic diagram of the lower connector structure of the present invention;

[0029] Figure 6 This is a schematic diagram of the Y-shaped guide head of the present invention;

[0030] Figure 7 This is a schematic diagram of the structure of sleeve A of the present invention;

[0031] Figure 8 This is a schematic diagram of the structure of sleeve B of the present invention;

[0032] Figure 9 This is a schematic diagram of the guide head and single-tube double-well water-proof guide pipe of the present invention;

[0033] Figure 10 This is a schematic diagram of the lower sleeve A and sleeve B of the present invention;

[0034] Figure 11 This is a schematic diagram of the cement grouting for solidifying the main wellbore and casing A according to the present invention;

[0035] Figure 12 This is a schematic diagram of the cement grouting and solidification sleeve B of the present invention.

[0036] Among them, 1. Upper connector; 1-1. Radial limiting groove; 1-2. Clamping screw hole; 2. Pipe body; 3. Lower connector; 3-1. Axial limiting groove; 3-2. Sealing ring groove; 3-3. Fixing pin hole; 4. Fixing pin; 5. Clamping screw; 6. Space dividing plate; 7. Sealing rubber; 8. Sealing ring; 9. Weld; 10. Y-type guide head; 10-1. Flow channel I; 10-2. Flow channel II; 10-3. Flow channel III; 10-4. Sealing surface; 11. One-way valve A; 12. One-way valve B; 13. Casing A; 14. Drillable blind plug; 15. Casing B; 16. Sealing rubber sleeve; 17. Seawater; 18. Mud surface; 19. Underwater mud; 20. Main wellbore; 21. Wellbore A; 22. Wellbore B; 23. Cement slurry. Detailed Implementation

[0037] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0038] like Figure 1-12 As shown, a single-tube double-well construction device includes a single-tube double-well water-proof guide pipe, a Y-type guide head 10, a one-way valve A11, a one-way valve B12, a casing A13, and a casing B15.

[0039] The single-tube double-well water-proof guide pipe includes a water-proof guide pipe body, a space-dividing plate 6, a sealing rubber 7, a fixing pin 4, a clamping screw 5, and a sealing ring 8. The water-proof guide pipe body includes an upper connector 1, a pipe body 2, and a lower connector 3, which are connected by welding. The weld seam 9 is located as shown in the figure. Figure 1 As shown. The upper part of the water-tight conduit body is an upper connector 1, and the lower part is a lower connector 3. The upper connector 1 is machined with a radial limiting groove 1-1 and a clamping screw hole 1-2 on its upper part, and the lower connector 3 is machined with an axial limiting groove 3-1, a sealing ring groove 3-2, and a fixing pin hole 3-3 on its lower part. When the two sections of the water-tight conduit body are connected, the upper connector 1 of one section of the water-tight conduit body and the lower connector 3 of the other section of the water-tight conduit body can be inserted into each other and limited and suspended by the fixing pin 4 and the clamping screw 5. Specifically, the fixing pin 4 is inserted into the radial limiting groove 1-1 and the fixing pin hole 3-3, and the clamping screw 5 is inserted into the clamping screw hole 1-2 and the axial limiting groove 3-1. The space dividing plate 6 is installed inside the water-tight conduit body. The two ends of the space dividing plate 6 are connected to the inner wall of the water-tight conduit body, dividing the internal space of the water-tight conduit body into two parts. The sealing rubber 7 is set at the upper and lower ends of the space dividing plate 6.

[0040] The Y-shaped guide head 10 is made of drillable material. The upper part of the guide head has the same structure as the upper part of the riser connector, allowing it to be inserted and connected to the lower riser connector. The internal flow channels of the Y-shaped guide head 10 are Y-shaped, divided into flow channels I10-1, II10-2, and III10-3. Flow channel I10-1 is located on one side of wellbore A21, and flow channel II10-2 is located on one side of wellbore B22. A one-way valve A11 is placed in flow channel I10-1, allowing fluid to flow upwards from the lower part of the Y-shaped guide head 10 within flow channel I10-1. A one-way valve B12 is placed in flow channel III10-3, allowing fluid to flow downwards from the upper part of the Y-shaped guide head 10 within flow channel III10-3.

[0041] The lower part of the casing A13 is connected to a drillable blind plug 14; the lower part of the casing B15 is vulcanized with a sealing rubber sleeve 16. When the casing B15 is inserted downward into the Y-shaped guide head 10, the sealing rubber sleeve 16 cooperates with the sealing surface 10-4 of the guide head to achieve fluid sealing.

[0042] The construction method of this invention is as follows:

[0043] Before connecting the riser, the space partition plate 6 is pre-installed inside the riser body, and the sealing rubber 7 is installed at the upper and lower ends of the space partition plate 6. When connecting the riser, insert the upper and lower connectors of the riser into place, rotate the riser to align the upper and lower connector limiting grooves, and install the fixing pins 4 and clamping screws 5 for axial and circumferential limiting. Simultaneously, the sealing rubber 7 at the lower part of the space partition plate 6 and the sealing rubber 7 at the upper part of another space partition plate 6 make an interference fit, providing a sealing function. The connection method between the Y-type guide head 10 and the riser is the same. After overall installation, the interior of the riser will be divided into two spaces, namely wellbore A21 and wellbore B22.

[0044] After the drill bit drills through the underwater soil 19 to a certain depth, the Y-type guide head 10 and the water-proof guide pipe are sequentially lowered to the predetermined depth according to the installation steps. Then, the casing A13 is lowered into the wellbore A21. The lower part of the casing A13 is connected to the drillable blind plug 14. After the casing A13 is lowered to contact the guide head, it is lifted up, leaving a gap between the drillable blind plug 14 and the Y-type guide head 10. The casing B15 is lowered into the wellbore B22. The lower part of the casing B15 is vulcanized and fitted with a sealing rubber sleeve 16. After the casing B15 is lowered into place, it is pressed down so that the sealing rubber sleeve 16 is inserted into the sealing surface 10-4 of the guide head. After casing A13 and casing B15 are lowered into place, cementing operations begin. Cement slurry 23 is injected through casing B15, flows through flow channel II10-2, and then through check valves A11 and B12, flow channel I10-1, and flow channel III10-3. The cement slurry 23 in the main borehole 20 and borehole A21 rises back to the mud surface 18. Then casing B15 is pulled up. After the mud in the main borehole 20 and borehole A21 has solidified, cement slurry 23 is injected through casing B15. At this time, cement slurry 23 only rises back in borehole B22. After rising back to the mud surface 18, it waits for the cement slurry to solidify. At this time, casing A13, casing B15, riser, and main borehole 20 form an integrated system through cementing, completing the single-tube dual-well operation. Subsequent drilling operations can then be carried out by drilling open the guide head and blind plug of the drillable material.

[0045] The embodiments described herein are preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Therefore, all equivalent changes made in accordance with the structure, shape, and principle of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A single-tube double-well construction device, comprising a water-tight guide pipe, characterized in that: A Y-shaped guide head (10) is connected to the lower end of the water-proof conduit; the water-proof conduit is composed of multiple sections of water-proof conduit body connected together, and a space dividing plate (6) is provided inside the water-proof conduit body. The space dividing plate (6) divides the inside of the water-proof conduit body into two spaces, into which sleeve A (13) and sleeve B (15) are respectively placed; a Y-shaped flow channel is formed inside the Y-shaped guide head (10), and a flat sealing surface (10-4) is formed in one of the branch flow channels. The sealing surface (10-4) contacts the bottom end of sleeve B (15); a one-way valve A (11) is provided in the other branch flow channel, and a one-way valve B (12) is provided in the main flow channel. The lower part of the casing A (13) is connected to a drillable blind plug (14). The lower part of the sleeve B (15) is vulcanized with a sealing rubber sleeve (16). The one-way valve A (11) causes the fluid to flow upward from the lower part of the Y-type guide head (10), and the one-way valve B (12) causes the fluid to flow downward from the upper part of the Y-type guide head (10).

2. The single-tube dual-well construction equipment according to claim 1, characterized in that: The water-proof conduit body includes an upper connector (1), a pipe body (2), and a lower connector (3) connected in sequence.

3. The single-tube double-well construction equipment according to claim 2, characterized in that: The upper part of the upper connector (1) is provided with a radial limiting groove (1-1) and a clamping screw hole (1-2); the lower part of the lower connector (3) is provided with an axial limiting groove (3-1) and a fixing pin hole (3-3); the radial limiting groove (1-1) matches the fixing pin hole (3-3) and a fixing pin (4) is inserted through it, and the clamping screw hole (1-2) matches the axial limiting groove (3-1) and a clamping screw (5) is inserted through it.

4. The single-tube dual-well construction equipment according to claim 1, characterized in that: Both ends of the space dividing plate (6) are provided with sealing rubber (7).

5. The single-tube double-well construction equipment according to claim 1, characterized in that: The upper part of the Y-shaped guide head (10) is provided with a radial limiting groove (1-1) and a clamping screw hole (1-2).

6. A method for constructing a single-tube dual-well system, characterized in that: Includes the following steps: S1. Before the water-proof conduit is connected and used, the space partition plate (6) is pre-installed inside the water-proof conduit body, and the sealing rubber (7) is installed on the upper and lower ends of the space partition plate (6); S2. When connecting the water-proof conduit, insert the upper and lower connectors of the water-proof conduit into the fit, rotate the water-proof conduit to align the upper and lower connector limiting grooves, install the fixing pin (4) and the clamping screw (5) to limit the axial and circumferential movement; at the same time, the sealing rubber (7) at the bottom of the space partition plate (6) and the sealing rubber (7) at the top of another space partition plate (6) are in an interference fit to play a sealing role; The connection method between the Y-type guide head (10) and the water-proof guide tube is the same as step S2; after the whole installation, the inside of the water-proof guide tube will be divided into two spaces, namely well hole A (21) and well hole B (22). S4. When the drill bit drills the underwater soil (19) to a certain depth, the Y-type guide head (10) and the water-proof guide pipe are successively lowered to the predetermined depth according to the installation steps. Then, the casing A (13) is lowered into the well hole A (21). After the casing A (13) is lowered to contact the guide head, it is lifted up, leaving a gap between the drillable blind plug (14) and the Y-type guide head (10). S5. Run casing B (15) into wellbore B (22). After casing B (15) is in place, press it down so that the sealing rubber sleeve (16) is inserted into the sealing surface (10-4) of the guide head. S6. After casing A (13) and casing B (15) are lowered into place, cementing operation begins. Cement slurry (23) is injected from casing B (15), flows through flow channel II (10-2), flows through check valve A (11), check valve B (12), flow channel I (10-1), and flow channel III (10-3), and the cement slurry (23) in the main wellbore (20) and wellbore A (21) rises back to the mud surface (18) position. Then casing B (15) is lifted. S7. After the mud in the main wellbore (20) and wellbore A (21) has solidified, cement slurry (23) is injected from casing B (15). The cement slurry (23) rises back in wellbore B (22) and waits for the cement slurry to solidify after rising to the mud surface (18). Casing A (13), casing B (15), water-proof guide pipe, and main wellbore (20) form an integrated system through cementing to complete the single-tube double-well construction operation.

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