Large-displacement horizontal well mechanical rotary guiding assembly based on well track control

Abstract

The invention discloses a large-displacement horizontal well mechanical rotary guiding assembly based on well track control, relates to the technical field of well drilling, and provides the following technical scheme aiming at the problems that vibration abrasion is caused by rigid contact between a traditional centralizer and a well wall, and fracture is caused by intermittent movement between the traditional centralizer and a drill bit. By means of the multi-connection righting assemblies distributed in an annular array mode, follow-up movement compensation of the multi-connection righting assemblies and change of the relative positions of contact fulcrums are formed through eccentric deflection, it is ensured that rigid contact between a drilling tool and a well wall is buffered, the intermittent movement phenomenon is reduced, and finally the purposes of reducing abrasion of the drilling tool and ensuring stable advancing of the drilling tool are achieved. In addition, by setting a limiting structure between the multi-connection centralizing assembly and the drill column system, extreme value limiting of the deviation angle in the drilling process is achieved, the adjustable range is reserved on the basis of dynamic adjustment, and it is ensured that play control over the multi-connection centralizing assembly is achieved in the well track control process of rotary steering drilling.

Description

Technical Field

[0001] The present invention relates to the technical field of drilling, and particularly to a mechanical rotary steerable assembly for extended reach horizontal wells based on wellbore trajectory control. Background Art

[0002] In terms of the technical principle and actual operating pressure analysis of the rotary steerable drilling system, the key vulnerable structures therein include: a hydraulic drive system, a guide sleeve and bearing assembly, a bit connection and power module, a drill string, a stabilizer, and a sealing system. The stabilizer mainly plays the roles of a fulcrum and a centralizer in the drill string assembly. The purpose of installing the stabilizer is to control the well inclination angle and wellbore curvature within the specified range, and to concentrate most of the weight of the drill collar on the bit, thereby reducing the non-wellbore center forces and other external forces borne by the drill string and the bit. With the development of stabilizers and the large-scale exploitation of horizontal wells and directional wells, the stabilizer has become an indispensable downhole drill tool in modern wellbore trajectory control technology.

[0003] The stabilizer is also called a centralizer. The centralizer is usually installed in the drill string system. Through mechanical structures (such as hydraulic pistons, eccentric gear trains, universal joints, etc.), the centralizer contacts the wellbore wall to form a fulcrum, and combines with the dynamic adjustment ability of the rotary steerable system to achieve the functions of steering control and wellbore trajectory control. However, during actual use, the frequent rigid contact with the wellbore wall causes vibrations, which are extremely likely to cause wear of the centralizer. Moreover, the frequent vibrations will also cause intermittent crossovers between the centralizer and the bit, resulting in fracture phenomena. Therefore, this application proposes a solution. Summary of the Invention

[0004] The purpose of the present invention is to provide a mechanical rotary steerable assembly for extended reach horizontal wells based on wellbore trajectory control, which is used to solve the problems of vibration wear caused by the rigid contact between the traditional centralizer and the wellbore wall, and fracture caused by the intermittent crossover with the bit.

[0005] The purpose of the present invention can be achieved by the following technical solutions: A mechanical rotary steerable assembly for extended reach horizontal wells based on wellbore trajectory control includes symmetrically arranged inner sleeves. A connecting cylinder is commonly installed between the pair of inner sleeves. Outer sleeves are sleeved outside the inner sleeves. A multi-link centralizer assembly is commonly provided between the adjacent ends of the pair of outer sleeves; The multi-link centralizer assembly includes a side link and a locking link that are rotatably connected. The side link and the locking link are distributed in two groups in a circular array. The side link at the end is rotatably connected to one end of the outer sleeve. An arc-shaped outward expansion rod is commonly installed in the middle of the outside of the side link and the locking link; A flexible tube is commonly connected to the middle of the inner sleeves. A radial displacement strip corresponding to the hinge joint of the pair of locking links is installed in the middle of the outside of the flexible tube. An eccentric gear train mechanism for the radial offset of the radial displacement strip is provided inside the inner sleeves.

[0006] It is further configured as follows: the multi-joint straightening assembly also includes an end hoop, which is threadedly installed on the inner ring side of the end of the outer casing and connected to the inner casing.

[0007] It is further configured as follows: the adjacent ends of the side connecting rod and the locking rod have the same structure and are interlocked with each other, the adjacent ends of the locking rod have the same structure and are interlocked with each other, and a bolt joint is provided at the outer end of the side connecting rod away from the locking rod, and the bolt joint is hinged to the end hoop.

[0008] It is further configured as follows: the eccentric gear train mechanism includes a centrally rotatably arranged active rotating tooth, an eccentric internal gear ring is rotatably installed on the inner side of the flexible tube, and the active rotating tooth is externally meshedly connected with a follower rotating tooth meshed with the eccentric internal gear ring.

[0009] It is further configured that: a driving component for driving the active rotating gear to rotate is arranged inside one of the inner sleeves.

[0010] It is further configured as follows: a locking thread is provided at the outer end of the inner casing, a positioning ring connected to the drill string system is installed on the inner casing through the locking thread, and a locking sleeve pin ring is installed on the end of the outer casing and is sleeved on the outer side of the inner casing.

[0011] It is further configured as follows: a return spring is sleeved on the outer wall of the inner sleeve corresponding to the outer sleeve, one end of the return spring is connected to the outer wall of the inner sleeve, and the other end of the return spring is connected to the inner wall of the outer sleeve.

[0012] It is further configured as follows: a straight hole is opened in the middle of the outer side of the side connecting rod and the locking rod, and a cross-sectional column hole is opened inwardly of the side connecting rod and the locking rod corresponding to the straight hole. The straight hole is connected with the cross-sectional column hole and forms an engagement cavity. Only horizontal sliding action is completed without the action of external force, and it will not fall off.

[0013] It is further configured as follows: displacement blocks are installed at both ends of the outward expansion rod, and a push ball column cooperating with the straight hole and the cross-sectional column hole is installed at the lower end of the displacement block. During the change of the "hinge state" of the side connecting rod and the locking rod, the displacement block on the outward expansion rod slides horizontally in the combined hole of the straight hole and the cross-sectional column hole through the push ball column, thereby realizing the change in the axial position of the contact fulcrum between the outward expansion rod and the well wall, that is, the change in the relative position of the contact fulcrum of the drilling tool.

[0014] The present invention has the following beneficial effects: In the present invention, on the one hand, a multi-link centering assembly distributed in an annular array forms a follow-up "cavitation compensation" of the multi-link centering assembly by eccentric deflection and changes in the relative positions of the contact fulcrums, ensuring that the rigid contact between the drill string and the wellbore is buffered and intermittent cavitation is reduced, ultimately achieving the purpose of reducing drill string wear and ensuring the smooth advancement of the drill string. On the other hand, by setting a limiting structure between the multi-link centering assembly and the drill string system, the extreme value of the deviation angle is limited during the drilling process, thereby controlling the well inclination angle and wellbore curvature, and leaving an adjustable range on the basis of dynamic adjustment, so as to ensure the cavitation control of the multi-link centering assembly during the wellbore trajectory control of rotary steerable drilling. During the cavitation control process, the drive motor drives the active rotating gear to rotate, thereby driving the driven rotating gear to drive the eccentric internal gear ring meshing with it to rotate eccentrically. At this time, the flexible pipe rotatably connected to the eccentric internal gear ring generates a "cavitation compensation" action, driving the radial displacement strip on the outside of the flexible pipe to generate a radial deformation action. Immediately, the "hinged state" of the side connecting rod and the locking rod on the outside of the radial displacement strip changes, that is, the folding angle of the side connecting rod and the locking rod changes. Finally, the relative position of the contact fulcrum of the outer expansion rod outside the side connecting rod and the locking rod changes, ensuring the smooth advancement of the drill string. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0016] Figure 1 is a schematic structural diagram of the present invention; Figure 2 is a front cross-sectional view of the present invention; Figure 3 is a schematic structural diagram of the multi-link centering assembly of the present invention; Figure 4 of the present invention Figure 2 is an enlarged schematic view of part A in; Figure 5 is a side view of the multi-link centering assembly of the present invention; Figure 6 is a schematic diagram of the structural disassembly of the multi-link rod of the present invention; Figure 7 is a schematic cross-sectional view of the structure of the multi-link rod of the present invention; Figure 8 is a side cross-sectional view of the present invention.

[0017] In the figure: 1. Outer sleeve; 2. Inner sleeve; 3. Positioning ring; 4. Locking sleeve pin ring; 5. Flexible tube; 6. Connecting cylinder; 7. End hoop; 8. Side connecting rod; 9. Locking rod; 10. Outer expanding rod; 11. Bolt joint; 12. Displacement block; 13. Pushing ball column; 14. Straight hole; 15. Section column hole; 16. Locking thread; 17. Return spring; 18. Radial displacement strip; 19. Eccentric internal gear ring; 20. Active rotating gear; 21. Follow-up rotating gear. Specific embodiments

[0018] The technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative work shall fall within the protection scope of the present invention.

[0019] Embodiment 1: Aiming at the problems of vibration wear caused by the rigid contact between the traditional centralizer and the wellbore wall and the fracture caused by the intermittent caving of the drill bit, the following technical solutions are proposed: Refer to Figure 1 - Figure 8 As shown, in this embodiment, a mechanical rotary steering assembly for a large-displacement horizontal well based on wellbore trajectory control includes symmetrically arranged inner sleeves 2. A connecting cylinder 6 is installed between a pair of inner sleeves 2. Outer sleeves 1 are sleeved outside the inner sleeves 2. A multi-link centralizer assembly is commonly arranged between the adjacent ends of a pair of outer sleeves 1; The multi-link centralizer assembly includes a side connecting rod 8 and a locking rod 9 that are rotatably connected. The side connecting rod 8 and the locking rod 9 are distributed in two groups in a circular array. The side connecting rod 8 at the end is rotatably connected to one end of the outer sleeve 1. An arc-shaped outer expanding rod 10 is commonly installed in the middle of the outer sides of the side connecting rod 8 and the locking rod 9. The multi-link centralizer assembly further includes an end hoop 7. The end hoop 7 is threadedly installed on the inner ring side of the end of the outer sleeve 1 and is connected to the inner sleeve 2. The adjacent end parts of the side connecting rod 8 and the locking rod 9 have the same structure and are engaged with each other. The adjacent end parts of the locking rod 9 also have the same structure and are engaged with each other. A bolt joint 11 is arranged at the outer end of the side connecting rod 8 away from the locking rod 9. The bolt joint 11 is hinged to the end hoop 7; Refer to Figure 3 As shown, the side connecting rod 8 and the locking rod 9 are connected in pairs and symmetrically engaged. The side connecting rod 8 at both ends is connected to the outer sleeve 1 through the end hoop 7. When the drill string contacts the wellbore wall during drilling, the outer expanding rod 10 first contacts the wellbore wall to form a fulcrum. At this time, the multi-link centralizer assembly forms a fold through the side connecting rod 8 and the locking rod 9 to complete the adjustment of the relative position of the contact fulcrum, so that the rigid contact between the drill string and the wellbore wall is buffered and the intermittent caving is reduced, ensuring the reduction of drill string wear and the prevention of fracture; It should be further noted that the above-mentioned "relative position of the contact fulcrum" refers to the position of the contact fulcrum between the drill string and the wellbore wall, which in this embodiment is the contact position between the outer arc top of the outer expansion rod 10 and the wellbore wall, and changes after the side connecting rod 8 and the locking rod 9 drive the outer expansion rod 10 to deform; Referring Figure 1 to Figure 2 as shown in and , a flexible pipe 5 is commonly connected to the middle of the inner casing 2. A radial displacement strip 18 corresponding to the hinge joint of a pair of locking rods 9 is installed in the middle of the outer side of the flexible pipe 5. An eccentric gear train mechanism for the radial offset of the radial displacement strip 18 is arranged inside the inner casing 2; Referring Figure 5 to Figure 7 and as shown in , straight holes 14 are provided in the middle of the outer sides of the side connecting rod 8 and the locking rod 9. Section column holes 15 are provided in the side connecting rod 8 and the locking rod 9 corresponding to the straight holes 14 inward. Displacement blocks 12 are installed at both ends of the outer expansion rod 10. A pushing ball column 13 that cooperates with the straight holes 14 and the section column holes 15 is installed at the lower end of the displacement block 12. The straight holes 14 and the section column holes 15 are connected and form a biting cavity, and only horizontal sliding actions are completed without falling off under non-external force; and considering the possible blockage problem caused by the accumulation of rock and soil during the drilling process, through the combination of the centralizer and the rotation action of the drill string itself, the accumulated rock and soil can be continuously thrown out during the drilling process;Referring to the above, during the change of the "hinged state" of the side link 8 and the locking link 9, the displacement block 12 on the expanding rod 10 horizontally slides in the combined holes of the straight hole 14 and the sectional column hole 15 through the pushing ball column 13, realizing the change of the contact fulcrum of the expanding rod 10 with the wellbore in the axial position, that is, the change of the relative position of the drill string contact fulcrum.

[0020] Basic principle: In this embodiment, a multi-link centralizer assembly is provided in the drill string system to achieve the control of the drill string's caving and smooth feeding during drilling. It is basically similar to the principle of the centralizer in the prior art. The difference lies in that through the multi-link centralizer assembly distributed in a circular array, the follow-up type "caving compensation" and the change of the relative position of the contact fulcrum are formed by eccentric deflection, ensuring that the rigid contact between the drill string and the wellbore is buffered and the intermittent caving phenomenon is reduced, ultimately achieving the purpose of reducing drill string wear and ensuring the smooth advancement of the drill string.

[0021] Embodiment 2: Combining Embodiment 1, by setting the limiting structure between the outer casing 1 and the inner casing 2 and the drill string system, the extreme value limitation of the deviation angle is realized during drilling, and the well inclination angle and the wellbore curvature are controlled. The difference from the conventional control method lies in that on the basis of dynamic adjustment, an adjustable range is reserved to ensure the caving control of the multi-link centralizer assembly during the wellbore trajectory control of rotary steerable drilling; Referring Figure 2 and Figure 4 As shown, a locking thread 16 is provided at the outer end of the inner casing 2. The inner casing 2 is provided with a positioning ring 3 connected to the drill string system through the locking thread 16. A locking sleeve ring 4 sleeving the outer side of the inner casing 2 is installed at the end of the outer casing 1. The inner casing 2 is sleeved with a return spring 17 corresponding to the outer wall of the outer casing 1. One end of the return spring 17 is connected to the outer wall of the inner casing 2, and the other end of the return spring 17 is connected to the inner wall of the outer casing 1.

[0022] Specifically: When assembling the inner casing 2 and the outer casing 1, the return spring 17 is pre-installed outside the inner casing 2 and one end is connected, and then the other end is connected to the inner wall of the outer casing 1. The positioning ring 3 is sleeved on one end of the inner casing 2 through the locking thread 16 to form a connection with the drill string system, and the sleeved length is determined in advance to avoid insufficient adjustable deviation during the dynamic adjustment of the relative position of the contact fulcrum of the multi-link centralizer assembly during drilling.

[0023] Embodiment 3: This embodiment combines the technical contents of Embodiment 1 and Embodiment 2. The present application proposes a usage method of a mechanical rotary steerable assembly for a long displacement horizontal well based on wellbore trajectory control, including the following steps: S1: First, install the return spring 17 outside the inner sleeve 2 and connect one end, and then connect the other end to the inner wall of the outer sleeve 1. The positioning ring 3 is sleeved on one end of the inner sleeve 2 through the locking thread 16 to form a connection with the drill string system, and the sleeved length is determined in advance. S2: During the drilling process of the drill tool, when the outer expansion rod 10 makes rigid contact with the well wall and produces intermittent caving, at this time, control the driving component to drive the eccentric internal gear ring 19 to rotate. The flexible pipe 5 rotatably connected to the eccentric internal gear ring 19 will produce a "caving compensation" action, driving the radial displacement strip 18 outside the flexible pipe 5 to produce a radial deformation action. Immediately, the "hinged state" of the side connecting rod 8 and the locking rod 9 outside the radial displacement strip 18 changes, that is, the folding angle of the side connecting rod 8 and the locking rod 9 changes. Finally, the relative position of the contact fulcrum of the outer expansion rod 10 jointly located outside the side connecting rod 8 and the locking rod 9 changes. S3: In S2, the specific process of the change in the folding angle of the side connecting rod 8 and the locking rod 9 is as follows. The displacement block 12 on the outer expansion rod 10 horizontally slides through the pushing ball column 13 in the combined hole of the straight hole 14 and the cross-sectional column hole 15, realizing the change in the axial position of the contact fulcrum between the outer expansion rod 10 and the well wall, that is, the change in the relative position of the drill tool contact fulcrum.

[0024] In summary: In the present invention, on the one hand, through the multi-link centralizer assembly distributed in a circular array, the follow-up type "caving compensation" and the change in the relative position of the contact fulcrum are formed by eccentric deflection of the multi-link centralizer assembly, ensuring that the rigid contact between the drill tool and the well wall is buffered and the intermittent caving phenomenon is reduced, and finally achieving the purpose of reducing drill tool wear and ensuring the smooth advancement of the drill tool. On the other hand, by setting the limiting structure between the multi-link centralizer assembly and the drill string system, the extreme value limitation of the deviation angle is realized during the drilling process, controlling the well inclination angle and the wellbore curvature, and reserving an adjustable range on the basis of dynamic adjustment, ensuring the caving control of the multi-link centralizer assembly during the wellbore trajectory control of rotary steerable drilling. Under the combined action of the two, the centralizer can perform mechanical rotary steerable control while controlling the wellbore trajectory, avoiding problems such as vibration wear caused by rigid contact with the well wall and fracture caused by intermittent caving with the drill bit.

[0025] The preferred embodiments of the present invention disclosed above are only used to help illustrate the present invention. The preferred embodiments do not describe all the details in detail, nor limit the present invention to only the specific implementation manners. Obviously, according to the content of this specification, many modifications and changes can be made. This specification selects and specifically describes these embodiments to better explain the principle and practical application of the present invention, so that those skilled in the art in the technical field can well understand and utilize the present invention. The present invention is only limited by the claims and their full scope and equivalents.

Claims

1. A mechanical rotary steering assembly for a large-displacement horizontal well based on wellbore trajectory control, comprising a symmetrically arranged inner casing (2), characterized in that: A connecting tube (6) is installed between the pair of inner sleeves (2), an outer sleeve (1) is sleeved on the outside of the inner sleeves (2), and a multi-connected straightening assembly is installed between the adjacent ends of the pair of outer sleeves (1); The multi-joint righting assembly comprises a side connecting rod (8) and a locking rod (9) which are rotatably connected to each other, and the side connecting rod (8) and the locking rod (9) are distributed in two groups of annular arrays, the side connecting rod (8) located at the end is rotatably connected to one end of the outer sleeve (1), and an arc-shaped outer expansion rod (10) is installed in the middle of the outer side of the side connecting rod (8) and the locking rod (9); The middle part of the inner sleeve (2) is connected to a flexible tube (5), the middle part of the outer side of the flexible tube (5) is equipped with a radial displacement strip (18) corresponding to the hinged part of a pair of locking rods (9), and an eccentric gear train mechanism for radial displacement of the radial displacement strip (18) is arranged inside the inner sleeve (2).

2. The large-displacement horizontal well mechanical rotary steering assembly based on wellbore trajectory control according to claim 1 is characterized in that: The multi-joint straightening assembly further comprises an end hoop (7), wherein the end hoop (7) is threadedly mounted on the inner ring side of the end of the outer sleeve (1) and is connected to the inner sleeve (2).

3. The large-displacement horizontal well mechanical rotary steering assembly based on wellbore trajectory control according to claim 2 is characterized in that: The adjacent ends of the side connecting rod (8) and the locking rod (9) have the same structure and interlock with each other, and the adjacent ends of the locking rod (9) have the same structure and interlock with each other. The outer end of the side connecting rod (8) away from the locking rod (9) is provided with a bolt joint (11), and the bolt joint (11) is hinged to the end hoop (7).

4. The large-displacement horizontal well mechanical rotary steering assembly based on wellbore trajectory control according to claim 1, characterized in that: The eccentric gear train mechanism comprises a centrally rotatably arranged active rotating tooth (20), an eccentric internal gear ring (19) is rotatably mounted on the inner side of the flexible tube (5), and the active rotating tooth (20) is externally meshedly connected with a follower rotating tooth (21) meshing with the eccentric internal gear ring (19).

5. The large-displacement horizontal well mechanical rotary steering assembly based on wellbore trajectory control according to claim 4 is characterized in that: A driving assembly for driving the active rotating gear (20) to rotate is arranged inside one of the inner sleeves (2).

6. The large-displacement horizontal well mechanical rotary steering assembly based on wellbore trajectory control according to claim 1, characterized in that: The outer end of the inner casing (2) is provided with a locking thread (16), and a positioning ring (3) connected to a drill string system is installed on the inner casing (2) via the locking thread (16). The end of the outer casing (1) is provided with a locking sleeve pin ring (4) sleeved on the outer side of the inner casing (2).

7. The mechanical rotary steering assembly for large-displacement horizontal wells based on wellbore trajectory control according to claim 6, characterized in that: The inner sleeve (2) is sleeved with a return spring (17) on the outer wall of the corresponding outer sleeve (1); one end of the return spring (17) is connected to the outer wall of the inner sleeve (2), and the other end of the return spring (17) is connected to the inner wall of the outer sleeve (1).

8. The large-displacement horizontal well mechanical rotary steering assembly based on wellbore trajectory control according to claim 1, characterized in that: A straight hole (14) is provided in the middle of the outer sides of the side connecting rod (8) and the locking rod (9), and a cross-section column hole (15) is provided inwardly of the side connecting rod (8) and the locking rod (9) corresponding to the straight hole (14).

9. The large-displacement horizontal well mechanical rotary steering assembly based on wellbore trajectory control according to claim 8, characterized in that: Displacement blocks (12) are installed at both ends of the outward expansion rod (10), and a displacement ball column (13) cooperating with the straight hole (14) and the cross-sectional column hole (15) is installed at the lower end of the displacement block (12).

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