A whipstock for building angle in ultra-short radius horizontal wells

Abstract

The present application discloses a whipstock for a horizontal well with an ultra-short radius, which includes a flexible drill pipe composed of a plurality of drill pipe short joints connected end to end. The drill pipe short joint includes: a drill pipe (3) and an outer sleeve assembly; both ends of the drill pipe (3) are respectively connected with external splines. The external splines are in an overall semi-spherical structure. The upper external spline and the lower external spline between two drill pipes (3) connected end to end form a ball head structure; the outer sleeve assembly has a ball seat structure that cooperates with the ball head structure, and key grooves corresponding to the upper external spline and the lower external spline are arranged on the ball seat structure; the upper external spline and the lower external spline are engaged for transmission; effectively solving the problems of unstable torque transmission and complex installation structure of the current universal joint type flexible drill tool.

Description

Technical Field

[0001] The present disclosure relates to the technical field of drilling tools for oil, coal mines, and exploration, specifically an ultra-short radius horizontal well deflecting drilling tool. Background Art

[0002] The statements in this section only provide background information related to the present disclosure and do not constitute prior art.

[0003] Ultra-short radius radial sidetracking horizontal well is an effective means to exploit remaining oil reservoirs. This technology directly creates a window in the original well casing. The main difference between it and a conventional horizontal well is that the curvature radius is extremely small, generally not greater than 4 m, and conventional drilling tools cannot meet this requirement, so special flexible drilling tools need to be used for drilling. The flexible drilling tool not only needs to bear loads such as axial force and torque, but also needs to have the ability to be easily bent and control the wellbore trajectory. The flexible drill pipe is the main component of the flexible drilling tool. It can not only transmit torque but also bear a certain axial force. In order to enable the flexible drilling tool to have a high directional deviation ability, the flexible drill pipe needs to be designed into a hinged structure, and its structural dimension design directly affects the bending and deviation ability of the drilling tool.

[0004] Patent CN 202047748 U discloses an ultra-short radius horizontal well flexible drilling tool, which is a ball cage type that realizes the bending rotation and torque transmission of the structure through the cooperation of balls and grooves. Because the torque transmission of this structure is the point contact between the balls and the grooves, the torque transmission of this structure is unstable.

[0005] Patent CN 207160977 U discloses an ultra-short radius well deflecting drilling tool. By setting a conventional three-section ball bearing on the flexible drilling tool, the friction between the flexible drilling tool and the outer pipe wall during torsion can be reduced. However, because it is a sliding friction with surface contact when there is an axial relative movement with the outer pipe wall, the transmission efficiency of the axial friction resistance load still needs to be improved.

[0006] Patent CN 106223871 A discloses a flexible drill pipe, which uses key grooves and transmission pins to achieve universal rotation. Each section of the drill pipe requires four assembled transmission pins, so the installation is relatively complex.

[0007] Therefore, the existing ultra-short radius horizontal well flexible drilling tools mostly adopt a ball cage type universal joint structure, which has defects such as unstable torque transmission, large friction resistance, and complex installation structure.

[0008] It should be noted that the information disclosed in the above background art section is only used to enhance the understanding of the background of the present disclosure, and therefore may include information that does not constitute prior art. Summary of the Invention

[0009] In view of this, the present disclosure provides a whipstock for ultra-short radius horizontal wells, which solves the problems of unstable torque transmission and complex installation structure of the universal joint type flexible drill tool at present.

[0010] To achieve the above-mentioned invention purpose, the whipstock for ultra-short radius horizontal wells includes a flexible drill pipe composed of a plurality of drill pipe short sections connected end to end. Among them, each drill pipe short section includes:

[0011] A drill pipe and an outer sleeve assembly;

[0012] Both ends of the drill pipe are respectively connected with external splines. The external splines are in an overall semi-spherical structure. The upper external spline and the lower external spline between two drill pipes connected end to end form a spherical head-like structure;

[0013] The outer sleeve assembly has a ball seat structure that cooperates with the spherical head-like structure, and key grooves corresponding to the upper external spline and the lower external spline are provided on the ball seat structure;

[0014] The upper external spline and the lower external spline are engaged for transmission.

[0015] In the present disclosure and possible embodiments, one end of the drill pipe is threadedly connected with a drill pipe head, and a first external spline is integrally provided on the drill pipe head; a second external spline is integrally provided at the other end of the drill pipe.

[0016] In the present disclosure and possible embodiments, the outer sleeve assembly includes:

[0017] A spline outer sleeve, a compression cap and a clamping member;

[0018] The ball seat structure is formed between the clamping member and the spline outer sleeve, and the compression cap is connected to the spline outer sleeve to limit the spherical head-like structure within the ball seat structure.

[0019] In the present disclosure and possible embodiments, the spline outer sleeve has concentrically matched tooth-shaped grooves, and the key teeth of the second external spline are concentrically assembled with the tooth-shaped grooves;

[0020] The interior of the clamping member has concentrically matched tooth-shaped chutes, and the key teeth of the first external spline are concentrically assembled with the tooth-shaped chutes.

[0021] In the present disclosure and possible embodiments, a spline groove is provided on the outer wall of the clamping member, and an internal spline is provided on the inner wall of the spline outer sleeve. The internal spline and the spline groove are concentrically assembled.

[0022] In the present disclosure and possible embodiments, in the upper and lower two-stage drill pipe short sections connected end to end, the bendable angle a between the upper drill pipe and the lower drill pipe is a ≤ 5°.

[0023] In the present disclosure and possible embodiments, the bendable angle a is 5°.

[0024] In the present disclosure and possible embodiments, a rolling bearing is connected to the outer wall of the jacket assembly.

[0025] In the present disclosure and possible embodiments, the rolling bearing is a dew-drop ball bearing.

[0026] For the whipstock drill for ultra-short radius horizontal wells of the present disclosure, each drill pipe joint of the flexible drill pipe can convert point contact into surface contact by using a steering hinge with key teeth type universal rotation in an overall spherical head structure instead of a steering hinge with ball cage type ball universal rotation, thereby reducing the concentrated stress of the structure, increasing the compactness and stability of the structure, and providing a strong guarantee for the stable transmission of torque; and changing the hinge composed of balls and key grooves to a hinge composed of key teeth and key groove structures greatly reduces the complexity of structure assembly; while transmitting torque, the flexible drill pipe can be bent according to the bending moment applied by the guide pipe through the excellent cooperation of the key tooth structure. Through the superposition of the bending angles of each section, the overall flexibility of the whipstock drill is large. Therefore, the drill of the present invention has the characteristics of stable torque transmission, simple assembly, and high load transmission efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Through the following description of the embodiments of the present disclosure with reference to the accompanying drawings, the above and other objects, features, and advantages of the present disclosure will become clearer. In the drawings:

[0028] Figure 1-1 is a schematic structural diagram of the flexible drill pipe (two-stage drill pipe joints) in the whipstock drill for ultra-short radius horizontal wells of the embodiment of the present disclosure;

[0029] Figure 1-2 is Figure 1-1 a sectional view of

[0030] Figure 2-1 is a front view of the spline jacket of the embodiment of the present disclosure;

[0031] Figure 2-2 is a top view of the spline jacket of the embodiment of the present disclosure;

[0032] Figure 2-3 is a bottom view of the spline jacket of the embodiment of the present disclosure;

[0033] Figure 3-1 is Figure 3-2 a sectional view taken along line A-A in

[0034] Figure 3-2 is a schematic structural diagram of the drill pipe head of the embodiment of the present disclosure;

[0035] Figure 3-3 is Figure 3-2 a side view in

[0036] Figure 4-1 is a front view of the drill pipe of the embodiment of the present disclosure;

[0037] Figure 4-2 is Figure 4-1 the upward view;

[0038] Figure 4-3 is Figure 4-1 the top view;

[0039] Figure 5-1 is the front view of the card component in the embodiment of the present disclosure;

[0040] Figure 5-2 is Figure 5-1 the top view;

[0041] Figure 5-3 is Figure 5-1 the upward view;

[0042] Figure 6-1 is the front view of the compression cap in the embodiment of the present disclosure;

[0043] Figure 6-2 is Figure 6-1 the upward view;

[0044] Figure 7 is the structural schematic diagram of the ball bearing in the embodiment of the present disclosure;

[0045] Figure 8 is the front view of the outer bearing in the embodiment of the present disclosure;

[0046] Figure 9-1 is the front view of the bearing cage in the embodiment of the present disclosure;

[0047] Figure 9-2 is Figure 9-1 the upward view;

[0048] Figure 10-1 is the structural schematic diagram of the flexible drill pipe (three - stage drill pipe short joint) in the embodiment of the present disclosure;

[0049] Figure 10-2 is Figure 10-1 the sectional view;

[0050] Figure 11 is the schematic diagram of the bending angle between the upper - level drill pipe and the lower - level drill pipe in this embodiment;

[0051] In the figure: 1 - spline outer sleeve; 2 - drill pipe head; 3 - drill pipe; 4 - clamping part; 5 - compression cap; 6 - rolling bearing; 101 - connecting thread; 102 - internal spline; 103 - tooth-shaped groove; 104 - chamfer; 201 - first external spline; 202 - arc structure; 203 - internal thread; 301 - second external spline; 302 - arc tooth; 303 - external thread; 401 - spline groove; 402 - tooth-shaped clamping groove; 403 - clamping groove; 501 - internal thread; 502 - chamfer; 601 - cage; 602 - outer bearing; 603 - bearing ball. Embodiment

[0052] The following describes the present disclosure based on embodiments. However, it is worth noting that the present disclosure is not limited to these embodiments. In the following detailed description of the present disclosure, some specific details are described in detail. However, those skilled in the art can also fully understand the present disclosure for the parts that are not described in detail.

[0053] In addition, those of ordinary skill in the art should understand that the provided drawings are only for illustrating the purpose, features, and advantages of the present disclosure, and the drawings are not actually drawn to scale. The serial numbers assigned to the components herein, such as "first", "second", etc., are only used to distinguish the described objects and do not have any sequential or technical meaning.

[0054] At the same time, unless the context clearly requires otherwise, the words such as "including", "comprising", etc. throughout the specification and claims should be interpreted as having an inclusive meaning rather than an exclusive or exhaustive meaning; that is, it is the meaning of "including but not limited to".

[0055] Figure 1-1 It is a schematic structural diagram of a flexible drill pipe (two-stage drill pipe short section) in an ultra-short radius horizontal well deflecting drill tool according to an embodiment of the present disclosure; Figure 1-2 It is a sectional view of FIG. 1; from Figure 1-1 and Figure 1-2 As shown, the ultra-short radius well deflecting drill tool according to an embodiment of the present disclosure includes a flexible drill pipe, and the flexible drill pipe is composed of a plurality of drill pipe short sections connected end to end; the drill pipe short section as a constituent unit of the flexible drill pipe specifically includes a spline outer sleeve 1, a drill pipe head 2, a drill pipe 3, a clamping part 4, a compression cap 5, and a rolling bearing 6, and an outer sleeve assembly is composed of the spline outer sleeve 1, the clamping part 4, and the compression cap 5.

[0056] First, the structures of the respective components of the drill pipe short section will be described with reference to the drawings:

[0057] From Figure 2-1 , 2-2As shown in FIGS. 2-3: For the spline outer sleeve 1 according to the embodiment of the present disclosure, a connecting thread 101 is provided at its upper end, and an internal spline 102 is provided on the inner wall of the upper end. The side wall of the internal spline 102 is a semi-circular arc curved surface; a bearing groove is provided on the outer wall of the middle part, and the cage 601 and the outer bearing 602 of the rolling bearing 6 can be stuck therein; a tooth-shaped groove 103 with concentric fit is provided on the inner wall of the lower end, and the side wall of the tooth-shaped groove 103 is an arc curved surface; a chamfer 104 is processed on the bottom edge.

[0058] From Figure 3-1 , 3-2 As shown in FIGS. 3-3: For the drill pipe head 2 according to the embodiment of the present disclosure, an internal thread 203 is provided at its center. The drill pipe head 2 base body is integrally connected with a first external spline 201. The side surface of the key teeth of the first external spline 201 is an arc-shaped structure 202, so that the first external spline 201 as a whole has a semi-spherical structure; the lower end of the first external spline 201 extends out of the base body so that the key teeth protrude.

[0059] From Figure 4-1 , 4-2 As shown in FIGS. 4-3: For the drill pipe 3 according to the embodiment of the present disclosure, a second external spline 301 is integrally connected at its upper end. The key teeth of the second external spline 301 are arc-shaped teeth 302, so that the second external spline 301 as a whole has a semi-spherical structure, and the key tooth structure of the second external spline 301 is matched with the structure of the tooth-shaped groove 103 on the inner wall of the lower end of the spline outer sleeve 1; in addition, the upper end of the second external spline 301 extends out of the base body so that the key teeth protrude. The drill pipe 3 can be meshed and driven with the protruding key teeth at the lower end of the drill pipe head 2 by using the protruding key teeth. Therefore, when the drill pipe short sections of the flexible drill pipe are connected end to end, the drill pipe 3 in the lower drill pipe short section and the drill pipe head 2 in the upper drill pipe short section can be meshed and driven. An external thread 303 is provided at its lower end, and the drill pipe 3 in the upper drill pipe short section is connected to the internal thread 203 of the lower drill pipe head 2 through the external thread 303 to achieve load transfer.

[0060] From Figure 5-1 , 5-2 As shown in FIGS. 5-3: For the clamping member 4 according to the embodiment of the present disclosure, a tooth-shaped clamping groove 402 with concentric fit is provided inside. The side wall of the tooth-shaped clamping groove 402 is an arc curved surface, and the structure of the tooth-shaped clamping groove 402 is matched with the key tooth structure of the drill pipe head 2; a spline groove 401 is provided on its outer wall, and the spline groove 401 fits with the internal spline 102 on the inner wall of the flower sleeve 1; a clamping groove 403 is provided at its bottom.

[0061] From Figure 6-1 , 6-2 As shown in: For the pressing cap 5 according to the embodiment of the present disclosure, a chamfer 502 is provided at its upper end, which is the same as the chamfer 104 at the upper end of the spline outer sleeve 1. An internal thread 501 is provided at the lower port of the pressing cap 5 and is connected to the connecting thread 101 at the upper end of the spline outer sleeve 1;

[0062] As shown in Figure 7 , 8 , 9-1, and 9-2, the rolling bearing 6 in the embodiments of the present disclosure adopts a leakage ball bearing. The outer bearing 602 of the ball bearing is concentrically fitted with the cage 601, and the bearing balls 603 are embedded inside the spherical grooves of the outer bearing 602 to form a complete bearing. The dew ball bearing converts the sliding friction between the drill string and the outer wellbore into rolling friction, effectively reducing the frictional force between the drill string and the outer wellbore, thereby improving the load transfer efficiency.

[0063] Then, with reference to the accompanying drawings, the assembly relationship of the flexible drill string with three-stage drill pipe nipples as shown in Figure 10-1 , 10-2 will be described:

[0064] First-stage drill pipe nipple: First, the key teeth of the second external spline 301 of the first-stage drill pipe 3 are concentrically assembled in the tooth-shaped groove 103 of the first-stage spline outer sleeve 1. The first-stage drill pipe head 2 is threadedly connected to the drilling torque. The first-stage drill pipe 3 uses the protruding key teeth to engage and drive with the protruding key teeth at the lower end of the drill pipe head 2, thereby transmitting the drilling torque downward to the first-stage drill pipe 3. Since both the first external spline 201 and the second external spline 301 are of a semi-spherical structure as a whole, at this time, the first external spline 201 of the drill pipe head 2 and the second external spline 301 are aligned to form a semi-spherical head structure. Then, the key teeth of the first external spline 201 outside the first-stage drill pipe head 2 are assembled and connected to the tooth-shaped card slot 402 inside the first-stage card 4. The first-stage spline outer sleeve 1 and the first-stage card 4 form a ball seat structure. The semi-spherical head structure is surrounded by the ball seat structure. At the same time, the spline groove 401 on the outer wall of the first-stage card 4 is assembled and connected to the internal spline 102 on the inner wall of the first-stage spline outer sleeve 1. Finally, the internal thread 501 of the first-stage compression cap 5 is connected to the connection thread 101 at the upper end of the first-stage spline outer sleeve 1, and the first-stage rolling bearing 6 is assembled in the bearing groove on the outer wall of the middle part of the first-stage spline outer sleeve 1. The connection of this first-stage drill pipe nipple is completed.

[0065] Second-stage drill pipe nipple: The lower end of the first-stage drill pipe 3 is connected end to end with the internal thread 203 of the second-stage drill pipe head 2 through the external thread 303. The key teeth of the second external spline 301 of the second-stage drill pipe 3 are assembled in the tooth-shaped groove 103 of the second-stage spline outer sleeve 1. The second external spline 301 of the second-stage drill pipe 3 and the first external spline 201 of the second-stage drill pipe head 2 form a semi-spherical head structure, and the protruding key teeth can be used for meshing and driving between them. After that, the connection methods of the second-stage card 4, the second-stage compression cap 5, and the second-stage rolling bearing 6 refer to the connection method of the above first-stage drill pipe nipple.

[0066] Third-stage drill pipe nipple: Just refer to the connection method of the second-stage drill pipe nipple.

[0067] The above connection is completed to form a flexible drill pipe with three-stage drill pipe nipples.

[0068] As Figure 11 shown, for the flexible drill pipe described in the embodiments of the present disclosure, in any two successively connected upper and lower drill pipe nipples, those skilled in the art know that due to the cooperation of the key teeth and key groove structures, a certain bendable angle a can be generated between the upper drill pipe 3 and the lower drill pipe 3. In the embodiments of the present disclosure, it is designed that the bendable angle a ≤ 5°, preferably 5°; due to the existence of this bendable angle a, the flexible drill pipe can be bent correspondingly under the action of bending moment to meet the requirements of the whipstock for horizontal wells with ultra-short curvature radius.

[0069] In addition, in the structural design of the drill pipe nipples of the present disclosure, the assembly connection of the tooth-shaped groove 103 and the second external spline 301 of the drill pipe 3 can better transmit torque and reduce the concentrated stress of the structure; the assembly connection of the internal spline 102 and the clamping member 4 ensures the stability of torque transmission of the structure and increases the overall conduction effect of the structure; the key teeth of the first external spline 201 are designed with an arc-shaped curved surface at the upper end, and the side surface at the upper end is an inclined plane that can generate a designed angle with the vertical plane, so as to ensure that the axis of the structure can be bent relative to the designed angle and is tangentially matched with the key teeth in a staggered manner, ensuring that the structure can rotate relatively to form a hinge structure and ensuring stable torque transmission; and the overall key teeth are of a semi-spherical structure, the side surface of the key teeth is an arc-shaped irregular curved surface that can be matched with the structure of the tooth-shaped groove 103, and its outer surface is a spherical surface, so as to ensure the structural stability and increase the structural sealing performance. The second external spline 301 has the same structure as the first external spline 201, and the tooth-shaped card slot 402 has the same structure as the tooth-shaped groove 103, so it also has the characteristics of making the structure more compact and the torque transmission more stable.

[0070] Therefore, when using the flexible whipstock described in the embodiments of the present disclosure, through the cooperation of various key teeth and key groove structures, the flexible whipstock can stably transmit the drilling torque; and while transmitting the drilling torque, through the delicate cooperation of the key tooth structures, the flexible drill pipe can be bent according to the bending moment applied by the guide pipe, and the longitudinal drilling can be changed to horizontal drilling within an ultra-short distance by superimposing the bending angles of each section.

[0071] The above-described embodiments are only for expressing the implementation manners of the present disclosure, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the patent of the present disclosure. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present disclosure, several deformations, equivalent replacements, improvements, etc. can be made, and these all belong to the protection scope of the present disclosure. Therefore, the protection scope of the patent of the present disclosure should be subject to the appended claims.

Claims

1. A whipstock for ultra-short radius horizontal well deviation, comprising a flexible drill pipe composed of a number of drill pipe short joints connected end to end, characterized in that, The drill pipe short joint includes: a drill pipe (3) and an outer sleeve assembly; Both ends of the drill pipe (3) are respectively connected with external splines. The external splines are integrally in a semi-spherical structure. The upper external splines and the lower external splines between two drill pipes (3) connected end to end form a spherical head structure; The outer sleeve assembly has a ball seat structure that cooperates with the spherical head structure, and key grooves corresponding to the upper external splines and the lower external splines are arranged on the ball seat structure; The upper external splines and the lower external splines are engaged for transmission.

2. The whipstock for ultra-short radius horizontal well according to claim 1, characterized in that: One end of the drill pipe (3) is threadedly connected to a drill pipe head (2), and a first external spline (201) is integrally arranged on the drill pipe head (2); a second external spline (301) is integrally arranged at the other end of the drill pipe (3).

3. The whipstock for building angle in ultra-short radius horizontal well according to claim 2, wherein, The outer sleeve assembly includes: a spline outer sleeve (1), a compression cap (5) and a clamping part (4); The ball seat structure is formed between the clamping part (4) and the spline outer sleeve (1), and the compression cap (5) is connected to the spline outer sleeve (1) to limit the spherical head structure within the ball seat structure.

4. The whipstock for ultra-short radius horizontal well according to claim 3, characterized in that: The spline outer sleeve (1) has concentrically matched tooth-shaped grooves (103), and the key teeth of the second external spline (301) are concentrically assembled with the tooth-shaped grooves (103); The inner part of the clamping part (4) has concentrically matched tooth-shaped chutes (402), and the key teeth of the first external spline (201) are concentrically assembled with the tooth-shaped chutes (402).

5. The whipstock for ultra-short radius horizontal well according to claim 4, characterized in that: A spline groove (401) is arranged on the outer wall of the clamping part (4), and an internal spline (102) is arranged on the inner wall of the spline outer sleeve (1). The internal spline (102) is concentrically assembled with the spline groove (401).

6. The whipstock for ultra-short radius horizontal well according to any one of claims 1-5, characterized in that: In the upper and lower two-level drill pipe short joints connected end to end, the bendable angle a between the upper-level drill pipe (3) and the lower-level drill pipe (3) is a≤5°.

7. The whipstock for ultra-short radius horizontal well according to claim 6, characterized in that: The bendable angle a is 5°.

8. The whipstock for ultra-short radius horizontal well according to claim 7, characterized in that: A rolling bearing (6) is connected to the outer wall of the outer sleeve assembly.

9. The whipstock for ultra-short radius horizontal well according to claim 8, characterized in that: The rolling bearing (6) adopts a dew-drop ball bearing.

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