Bypass device and method for casing drilling

Abstract

The invention belongs to the technical field of petroleum drilling, and particularly relates to a casing drilling bypass device and method. The casing drilling bypass device is arranged between a casing string and a drilling tool and comprises a connecting pipe, the connecting pipe is coaxially arranged between the casing string and the drilling tool, and at least one bypass hole is formed in the pipe wall of the connecting pipe; the ball seat is fixedly arranged in the connecting pipe through a shear pin, and the bypass hole is blocked by the ball seat; when the ball seat moves relative to the connecting pipe, a ball is thrown into the ball seat for pressing, and the shear pin for fixing the ball seat can be sheared off, so that the ball seat moves relative to the connecting pipe, and the bypass hole is further opened. The drilling and completion process can be simplified, the drilling and completion cost is reduced, and the drilling and completion quality is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of oil drilling, and specifically relates to a casing drilling bypass device and a casing drilling method. Background Art

[0002] The cost of the drilling engineering for the new production capacity in old oilfields is high. The conventional drilling process technology has entered a "bottleneck period" in terms of the operation process of improving the speed and reducing the cost by optimizing tools and parameters. There is a need to innovate the process idea, reduce the drilling cost, and effectively utilize the reserves.

[0003] The present invention proposes a casing drilling technology, which means that during the drilling process, the casing is used to replace the drill pipe string to complete the drilling operation. After using the casing to replace the drill pipe, the process of pulling out the drill pipe and then running in the casing in the conventional drilling process is saved, thereby effectively simplifying the drilling construction process and achieving fast, economical and efficient well construction.

[0004] During the casing drilling construction process, how to safely and efficiently cement after drilling and provide a qualified wellbore for oilfield development is a problem that must be solved.

[0005] During the implementation of casing drilling, after drilling is completed, cementing is directly carried out using the casing, so the drill string assembly at the bottom of the casing is not retrieved. Due to the relatively high density of the cement slurry for cementing, during the process of pumping the cement slurry by the cementing pump after drilling is completed, the cement slurry needs to enter the annulus through the narrow gap of the drill string, so a relatively large pumping pressure is required, resulting in problems such as too high equipment load, great downhole safety risks, long cementing construction time, and difficult to guarantee the cementing quality.

[0006] Therefore, in view of the above technical problems, it is urgent to develop a casing drilling bypass device and a casing drilling method. Summary of the Invention

[0007] In view of the above technical problems, the present invention aims to propose a casing drilling bypass device, which can solve at least one of the above technical problems.

[0008] The present invention also proposes a casing drilling method, which can solve the problem of excessive pumping pressure during the process of pumping cement slurry for cementing in the casing drilling process.

[0009] According to the present invention, there is provided a casing drilling bypass device, which is arranged between the casing string and the drill string and includes:

[0010] A connecting pipe, the connecting pipe is coaxially arranged between the casing string and the drill string, and at least one bypass hole is arranged on the pipe wall of the connecting pipe;

[0011] A ball seat, the ball seat is fixedly arranged in the connecting pipe through a shear pin and blocks the bypass hole;

[0012] When a ball is thrown into the ball seat for pressing, the shear pin fixing the ball seat can be cut off, so that the ball seat moves relative to the connecting pipe, and then the bypass hole is opened.

[0013] In a specific embodiment, a valve core is further included. The valve core is arranged above the ball seat and is configured to enable the one-way flow of fluid.

[0014] In a specific embodiment, a plurality of bypass holes are uniformly arranged on the connecting pipe along the circumferential direction.

[0015] In a specific embodiment, the upper end of the connecting pipe is connected to the drill collar by means of threaded connection.

[0016] In a specific embodiment, an external thread is provided at the lower end of the drill collar, and an internal thread is provided at the upper end of the connecting pipe.

[0017] In a specific embodiment, the connection between the connecting pipe and the drill collar is set as a conical surface.

[0018] In a specific embodiment, a measurement-while-drilling instrument is arranged in the drill collar.

[0019] According to the present invention, a casing drilling method is further provided. By using the casing drilling bypass device provided by the present invention, during drilling, the bypass hole is blocked by the ball seat, so as to carry out drilling fluid circulation. During cementing, a ball is thrown into the ball seat and pressed, so that the ball seat moves relative to the connecting pipe, thereby opening the bypass hole, and the bypass hole is used for pumping cement slurry.

[0020] In a specific embodiment, after throwing a ball into the ball seat for pressing, a valve core is pumped above the ball seat.

[0021] In a specific embodiment, the measurement-while-drilling instrument is taken out before throwing a ball into the ball seat for pressing.

[0022] Compared with the prior art, the advantages of the present application are as follows.

[0023] The present invention provides a bypass device for casing drilling and a casing drilling method. A drill string is arranged at the bottom of the casing, and the casing and the drill string are connected through the bypass device. During the drilling process, the casing drives the drill string to rotate to complete the drilling. After the drilling is completed, a sphere is put into the bypass device through the casing and pressure is pumped. After the sphere is sealed with the ball seat, under the action of the pressure, the ball seat moves downward relative to the connecting pipe, thereby opening the bypass hole on the connecting pipe. After the bypass hole on the connecting pipe is opened, the process of pumping cement slurry is carried out. At this time, the cement slurry can enter the annulus through the bypass hole to complete the cementing. By drilling in this way, the problem of excessive pumping pressure of the cement slurry can be solved, thereby reducing the load of the pumping equipment, reducing the downhole safety risk, reducing the cementing construction time, and enhancing the cementing quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The present invention will be described below with reference to the accompanying drawings.

[0025] Figure 1 FIG. shows a schematic diagram of an embodiment of a casing drilling bypass device according to the present invention;

[0026] Figures 2 to 5 FIG. shows a schematic diagram of the casing drilling bypass device according to the present invention during the working process.

[0027] In the figure: 1, measurement-while-drilling instrument; 2, drill collar; 3, sphere; 4, bypass hole; 5, valve core; 6, connecting pipe; 7, ball seat; 100, casing drilling bypass device.

[0028] In this application, all the drawings are schematic drawings, only used to illustrate the principle of the present invention, and are not drawn according to the actual ratio. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0029] The present invention will be introduced below with reference to the accompanying drawings.

[0030] It should be noted that the directional terms or limiting words "up", "down", etc. used in this application are all with reference to the Figure 1 mentioned. They do not limit the absolute positions of the components involved, but can vary according to specific situations.

[0031] Figure 1 FIG. shows the structure of the casing drilling bypass device 100 according to the present invention. As Figure 1 shown, the casing drilling bypass device 100 is arranged between the casing string and the drill string.

[0032] During the drilling process, the casing drives the drill to rotate. At this time, the casing drilling bypass device 100 acts as a section of conventional pipe string and can be used for drilling fluid circulation. That is to say, during the drilling process, the drilling fluid flows normally. For example, during the process that the drilling fluid enters from the top of the casing and then returns from the top of the annulus, the drilling fluid flows through the casing, the casing drilling bypass device 100 and the drill string in sequence, and then flows from the holes of the drill string for circulating the drilling fluid to the annulus, and finally returns from the top of the annulus.

[0033] After the drilling is completed, the casing drilling bypass device 100 can be used for pumping cement slurry. That is to say, during cementing, the bypass hole 4 on the side wall of the casing drilling bypass device 100 is opened. When pumping cement slurry into the casing, the cement slurry flows downward along the casing. When the cement slurry flows to the casing drilling bypass device 100, the cement slurry can enter the annulus through the bypass hole 4, and finally the annulus is filled with cement slurry.

[0034] On the one hand, the casing drilling bypass device 100 of the present invention can meet the construction requirements of the casing drilling process. On the other hand, it can provide a channel for pumping cement slurry during cementing, that is, the bypass hole 4. The aperture of the bypass hole 4 is larger than the aperture of the drill string for circulating drilling fluid, which can solve problems such as too high load of the cement slurry pumping equipment, high downhole safety risk, long cementing construction time, and difficult to guarantee cementing quality.

[0035] It is easy to understand that the "annulus" in the present invention refers to the space between the casing and the wellbore wall.

[0036] In a specific embodiment, the casing drilling bypass device 100 includes a connecting pipe 6. The connecting pipe 6 is coaxially arranged between the casing string and the drill string. In this embodiment, the upper end of the connecting pipe 6 is coaxially and fixedly connected to the drill collar 2, and the upper end of the drill collar 2 is coaxially and fixedly connected to the casing.

[0037] At least one bypass hole 4 is provided on the pipe wall of the connecting pipe 6. A ball seat 7 is also arranged inside the connecting pipe 6. The ball seat 7 is fixedly arranged inside the connecting pipe 6 through a shear pin, and the ball seat 7 blocks the bypass hole 4. That is to say, before the ball seat 7 moves relative to the connecting pipe 6, the bypass hole 4 is in a closed state, and the fluid can only flow along the axis direction of the connecting pipe 6. With this setting, conventional drilling fluid circulation can be carried out during the drilling process.

[0038] In a specific embodiment, at least two seals are arranged between the outer wall of the ball seat 7 and the inner wall of the connecting pipe 6. The two seals are respectively located on the upper and lower sides of the bypass hole 4, so that the ball seat 7 can block the bypass hole 4.

[0039] When the cementing process needs to be implemented, a ball is dropped into the ball seat 7 and pressured, that is, the ball 3 is pumped into the ball seat 7. Under the action of pressure, the shear pin fixing the ball seat 7 is cut off, so that the ball seat 7 moves downward relative to the connecting pipe 6, and then the bypass hole 4 is opened. Through this setting, the bypass hole 4 can be used as a channel for the circulation of cement slurry, thus solving problems such as excessive load of the cement slurry pumping equipment, high downhole safety risks, long cementing construction time, and difficult guarantee of cementing quality.

[0040] In a preferred embodiment, a plurality of bypass holes 4 are uniformly arranged on the connecting pipe 6 in the circumferential direction. Arranging a plurality of bypass holes 4 and uniformly arranging them on the connecting pipe 6 can make the cement slurry evenly distributed circumferentially in the annulus, improving the cementing quality.

[0041] In a preferred embodiment, the casing drilling bypass device 100 further includes a valve core 5. The valve core 5 is arranged above the ball seat 7, and the valve core 5 is configured to allow fluid to flow unidirectionally. By setting the valve core 5, a normal channel can be provided for injecting drilling fluid and cement slurry into the wellbore, and the reverse flow of drilling fluid and cement slurry can be effectively prevented. It is easy to understand that the valve core 5 can be arranged at any position in the casing or the connecting pipe 6 as long as the valve core 5 is located above the bypass hole 4.

[0042] In a specific embodiment, as Figure 1 shown, the valve core 5 is located in the casing above the drill collar 2.

[0043] In a specific embodiment, the upper end of the connecting pipe 6 is connected to the drill collar 2 by means of threaded connection. An external thread is provided at the lower end of the drill collar 2, and an internal thread is provided at the upper end of the connecting pipe 6. Further, the connection between the connecting pipe 6 and the drill collar 2 is set as a conical surface.

[0044] In a preferred embodiment, a measurement-while-drilling instrument 1 is arranged in the casing. As Figure 1 shown, in this embodiment, the measurement-while-drilling instrument 1 is arranged in the casing above the drill collar 2.

[0045] According to the present invention, there is also provided a casing drilling method. A drill string is coaxially arranged at the lower part of the casing. During the drilling process, the drill string is driven to rotate through the casing, so as to drill in the formation. After the drilling is completed, a bypass hole 4 for pumping cement slurry is opened on the side wall of the casing above the drill string, so as to provide a channel for pumping cement slurry.

[0046] In a specific embodiment, the casing drilling bypass device 100 provided by the present invention is used for drilling and cementing, and the specific steps are as follows.

[0047] During the drilling process, as Figure 2As shown, the ball seat 7 seals the side through-hole 4. At this time, the casing drilling bypass device 100 functions similar to a casing. The casing transmits torque to the drill string through the casing drilling bypass device 100, thereby drilling the formation.

[0048] Then, as Figure 3 shown, the measurement-while-drilling instrument 1 is taken out, and a sphere 3 is pumped into the casing until the sphere 3 enters the ball seat 7 and seals the ball seat 7.

[0049] Then, as Figure 4 shown, a valve core 5 is lowered into the casing until the valve core 5 is pumped in place.

[0050] Then, as Figure 5 shown, pressure is pumped into the casing, thereby pushing the ball seat 7 to move downward relative to the connecting pipe 6 to release the blockage of the side through-hole 4. At this time, the fluid inside the casing can enter the annulus through the side through-hole 4.

[0051] Finally, cement slurry is pumped into the casing. The cement slurry flows downward along the casing, then flows through the drill collar 2 and the connecting pipe 6, enters the annulus from the side through-hole 4 on the wall of the connecting pipe 6, and finally the cement slurry fills the entire annulus to complete the pumping of the cement slurry for well cementing.

[0052] In the description of the present invention, it should be understood that the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present invention, "a plurality" means two or more unless otherwise specifically defined.

[0053] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected to", "fixed", etc. should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0054] In the description of this specification, the descriptions referring to terms such as "one embodiment", "some embodiments", "examples", "specific examples", or "some examples", etc. mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0055] Finally, it should be noted that the above are only the preferred implementation schemes of the present invention and do not constitute any limitation to the present invention. Although the present invention has been described in detail with reference to the foregoing implementation schemes, for those skilled in the art, it is still possible to modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A casing drilling bypass device, characterized in that, Installed between the casing string and the drill string, including: A connecting pipe (6), the connecting pipe is coaxially arranged between the casing string and the drill string, and at least one side through-hole (4) is arranged on the pipe wall of the connecting pipe (6); A ball seat (7), the ball seat (7) is fixedly arranged in the connecting pipe (6) through a shear pin and plugs the side through-hole (4); By dropping a ball into the ball seat (7) and applying pressure, the shear pin fixing the ball seat (7) can be cut off, so that the ball seat (7) moves relative to the connecting pipe (6), and then the side through-hole (4) is opened.

2. The casing drilling bypass device according to claim 1, characterized in that, It further includes a valve core (5), the valve core (5) is arranged above the ball seat (7), and the valve core (5) is configured to allow fluid to flow unidirectionally.

3. The casing drilling bypass device according to claim 2, characterized in that, A plurality of side through-holes (4) are uniformly arranged on the connecting pipe (6) along the circumferential direction.

4. The casing drilling bypass device according to claim 1, wherein The upper end of the connecting pipe (6) is connected to the drill collar (2) by means of a threaded connection.

5. The casing drilling bypass device according to claim 4, characterized in that, An external thread is provided at the lower end of the drill collar (2), and an internal thread is provided at the upper end of the connecting pipe (6).

6. The casing drilling bypass device according to claim 5, wherein, The connection between the connecting pipe (6) and the drill collar (2) is set as a conical surface.

7. The casing drilling bypass device according to claim 4, characterized in that, A measurement-while-drilling instrument (1) is arranged in the drill collar.

8. A casing drilling method, characterized in that When using the casing drilling bypass device according to any one of claims 1 to 7, During drilling, the side through-hole (4) is blocked by the ball seat (7), so as to carry out drilling fluid circulation, During cementing, a ball is dropped into the ball seat (7) and pressure is applied to make the ball seat (7) move relative to the connecting pipe (6), so as to open the side through-hole (4), and the side through-hole (4) is used for pumping cement slurry.

9. The casing drilling method according to claim 8, wherein After dropping a ball into the ball seat (7) and applying pressure, the valve core (5) is pumped above the ball seat (7).

10. The casing drilling method according to claim 8, characterized in that, Before dropping a ball into the ball seat (7) and applying pressure, the measurement-while-drilling instrument (1) is withdrawn.

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