Downhole drill string pushing device

Abstract

The present invention relates to a downhole drill string propulsion device, which comprises a tool outer cylinder. A worm shaft is arranged inside the tool outer cylinder, and a central hole of the worm shaft is provided on the worm shaft. Radially symmetrically arranged rolling wheel structures are provided on the side wall of the tool outer cylinder. The rolling wheel structure comprises a rolling wheel capable of meshing with the worm shaft. The outer wall of the rolling wheel can abut against the wellbore. The worm shaft drives the rolling wheel to rotate so that the rolling wheel and the wellbore interact to generate a forward thrust. At least a pair of radially symmetrically arranged forward wheel structures are provided on the side wall of the tool outer cylinder. The forward wheel structure comprises a forward wheel capable of contacting the wellbore. The outer shape of the forward wheel is arranged in a parabola to reduce the pipe string friction coefficient. In the downhole drill string propulsion device of the present invention, the forward wheel structure can effectively reduce the pipe string friction coefficient. The rolling wheel structure interacts with the wellbore to generate an additional thrust and actively pulls the drill pipe string. The structure of the present invention is simple, has fewer components and strong reliability, meeting the requirement of greatly improving the wellbore extension limit.

Description

Technical Field

[0001] The present invention relates to the field of oil and gas drilling, particularly to the field of directional well and horizontal well drilling engineering technologies, and more particularly to a downhole drill string pushing device. Background Art

[0002] At present, during the drilling process of directional wells and horizontal wells, the drill string usually contacts the lower wellbore under the action of its own weight, resulting in an increase in frictional force during the drilling process, a decrease in the weight on bit of the drill bit, and even a reduction to zero, seriously affecting the drilling speed. Currently, installing roller friction reducers or hydraulic oscillators is often used to solve the above problems. The roller friction reducer suspends the original drill pipe collar through the wheels on the outer shell, converting the sliding friction between the collar and the wellbore into rolling friction between the rollers and the wellbore, reducing the friction coefficient, and thus reducing the frictional force of the pipe string; the hydraulic oscillator converts the temporary static friction of the drill string at the bottom of the well into dynamic friction through the longitudinal vibration generated by itself, reducing the frictional resistance.

[0003] The roller friction reducer and the hydraulic oscillator mainly achieve the purpose of reducing wear and resistance by reducing the friction coefficient, but they cannot generate an active pulling force in the direction of the wellbore axis, belonging to passive wear and resistance reduction tools, and it is difficult to greatly improve the wellbore extension limit of horizontal wells.

[0004] Therefore, based on years of experience and practice in the relevant industry, the inventor of the present invention proposes a downhole drill string pushing device to overcome the defects of the prior art. Summary of the Invention

[0005] The purpose of the present invention is to provide a downhole drill string pushing device to solve the problems existing in the prior art. In the downhole drill string pushing device of the present invention, the forward wheel structure can effectively reduce the friction coefficient of the pipe string, and the rolling wheel structure interacts with the wellbore to generate an additional thrust force to actively pull the drill pipe string. The structure of the present invention is simple, with fewer components and strong reliability, meeting the requirement of greatly improving the wellbore extension limit.

[0006] The purpose of the present invention is achieved as follows: A downhole drill string pushing device includes a tool outer cylinder, a worm shaft is arranged inside the tool outer cylinder, and a worm shaft central hole penetrating axially is arranged on the worm shaft; radially symmetric rolling wheel structures are arranged on the side wall of the tool outer cylinder, the rolling wheel structure includes a rolling wheel that can mesh with the worm shaft, the outer wall of the rolling wheel can abut against and contact the wellbore, and the worm shaft drives the rolling wheel to rotate so that the rolling wheel interacts with the wellbore to generate a forward thrust force; at least a pair of radially symmetric forward wheel structures are arranged on the side wall of the tool outer cylinder, the forward wheel structure includes a forward wheel that can contact the wellbore, and the outer shape of the forward wheel is parabolic to reduce the friction coefficient of the pipe string.

[0007] In a preferred embodiment of the present invention, the central axis of the rolling wheel is arranged in parallel with the central axis of the tool outer cylinder. A strip-shaped thread is provided on the outer wall of the rolling wheel, and the strip-shaped thread can mesh with the worm shaft, and the outer wall of the strip-shaped thread can abut against the wellbore wall.

[0008] In a preferred embodiment of the present invention, rolling wheel mounting through slots are radially symmetrically arranged on the side wall of the tool outer cylinder. Roller shaft hinge seats are respectively arranged at both axial ends of each rolling wheel mounting through slot. Roller shafts are arranged at both ends of the rolling wheel, and the roller shafts are hinged in the roller shaft hinge seats.

[0009] In a preferred embodiment of the present invention, the roller shaft hinge seat includes a seat platform, a gland, and a first fixing pin. The seat platform is arranged at both axial ends of the rolling wheel mounting through slot. An arc-shaped groove is provided on the seat platform, and the gland can be snap-connected to the seat platform. The gland is detachably connected to the seat platform through the first fixing pin; a convex ring with an increasing diameter is arranged at one end of each roller shaft away from the strip-shaped thread, and a clamping groove with an increasing diameter is arranged at one end of the arc-shaped groove away from the strip-shaped thread. The convex ring can be rotatably arranged in the clamping groove to axially fix the rolling wheel.

[0010] In a preferred embodiment of the present invention, each forward wheel structure includes a forward wheel group. The forward wheel group includes a plurality of forward wheels arranged in parallel at intervals. The central axis of each forward wheel is arranged perpendicular to the central axis of the tool outer cylinder in space; forward wheel shafts are respectively arranged at both axial ends of each forward wheel, and each forward wheel shaft is hinged to the tool outer cylinder.

[0011] In a preferred embodiment of the present invention, forward wheel mounting through slots are radially symmetrically arranged on the side wall of the tool outer cylinder. Each forward wheel passes through the forward wheel mounting through slot; a first support plate and a second support plate are respectively arranged on both circumferential sides of the forward wheel mounting through slot. The forward wheel shafts at both ends of each forward wheel are respectively hinged to the first support plate and the second support plate.

[0012] In a preferred embodiment of the present invention, a plurality of mounting shaft holes are respectively provided on the first support plate and the second support plate. Needle roller bearings are arranged in each mounting shaft hole, and each forward wheel shaft is hinged in each needle roller bearing.

[0013] In a preferred embodiment of the present invention, inner bosses are respectively arranged at both axial ends of each advancing wheel mounting through slot, connection through holes are respectively arranged in each inner boss, threaded connection holes are respectively arranged at both ends of the first support plate, connection through holes are respectively arranged at both ends of the second support plate, the connection through holes, the connection through holes and the threaded connection holes penetrate through second fixing pins, and each second fixing pin fixedly connects the first support plate and the second support plate in the advancing wheel mounting through slot.

[0014] In a preferred embodiment of the present invention, two pairs of the advancing wheel structures are arranged on the side wall of the tool outer cylinder, the two pairs of the advancing wheel structures are arranged at intervals along the axial direction of the tool outer cylinder, and the two pairs of the advancing wheel structures are arranged in a circumferential stagger of 90°.

[0015] In a preferred embodiment of the present invention, joints are respectively connected to both ends of the tool outer cylinder, an axially penetrating joint center hole is arranged on the joint, and the joint center hole is communicated with the worm shaft center hole to form a drilling fluid circulation channel; limiting shoulders are arranged at both axial ends of the worm shaft, and the limiting shoulders are connected to the tool outer cylinder in a matching manner through thrust bearings.

[0016] As described above, the downhole drill string pushing device of the present invention has the following beneficial effects:

[0017] In the downhole drill string pushing device of the present invention, the advancing wheel structure can effectively reduce the pipe string friction coefficient, the rolling wheel structure interacts with the well wall to generate an additional thrust, and actively pulls the drill pipe string; a large-diameter drilling fluid circulation channel is reserved in the worm shaft, reducing the pressure loss of the flowing drilling fluid; in the downhole drill string pushing device of the present invention, the two pairs of advancing wheel structures can ensure that there is always an advancing wheel in contact with the lower well wall during directional and horizontal drilling, ensuring the effect of reducing friction; the downhole drill string pushing device of the present invention has a simple structure, fewer components, strong reliability, and can also increase the pulling force by being used in series, meeting the requirement of greatly increasing the wellbore extension limit. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The following drawings are only intended to illustrate and explain the present invention schematically and do not limit the scope of the present invention. Among them:

[0019] Figure 1 : is a schematic diagram of the downhole drill string pushing device of the present invention.

[0020] Figure 2 : is a side view of the downhole drill string pushing device of the present invention.

[0021] Figure 3 : is an internal structure diagram of the downhole drill string pushing device of the present invention.

[0022] Figure 4: An exploded view of the forward wheel structure of the present invention.

[0023] Figure 5 : An exploded view of the rolling wheel structure of the present invention.

[0024] Figure 6 : A schematic diagram of the working state of the downhole drill string pushing device of the present invention.

[0025] In the figure:

[0026] 1. Connector;

[0027] 2. Tool outer cylinder; 21. Rolling wheel installation through slot; 22. Forward wheel installation through slot;

[0028] 3. Forward wheel structure; 31. Forward wheel; 32. Needle roller bearing; 33. First support plate; 34. Second support plate; 35. Second fixing pin;

[0029] 4. Rolling wheel structure; 41. Gland; 42. First fixing pin; 43. Rolling wheel; 44. Roller shaft; 45. Convex ring;

[0030] 5. Thrust bearing;

[0031] 6. Worm shaft;

[0032] 7. Formation;

[0033] 8. Wellbore. Detailed implementation manners

[0034] For a clearer understanding of the technical features, objectives, and effects of the present invention, the specific implementation manners of the present invention will now be described with reference to the accompanying drawings.

[0035] The specific implementation manners of the present invention described herein are only for the purpose of explaining the present invention and should not be construed in any way as a limitation of the present invention. Under the teaching of the present invention, those skilled in the art can conceive any possible variations based on the present invention, and these should all be regarded as belonging to the scope of the present invention. It should be noted that when an element is referred to as being "disposed on" another element, it can be directly on the other element or there can also be an intermediate element. When an element is considered to be "connected" to another element, it can be directly connected to the other element or there may be an intermediate element at the same time. The terms "installed", "connected", and "connected" should be understood in a broad sense. For example, it can be a mechanical connection or an electrical connection, or it can also be the communication inside two elements. It can be directly connected or indirectly connected through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms can be understood according to specific circumstances. The terms "vertical", "horizontal", "upper", "lower", "left", "right", and similar expressions used herein are only for the purpose of illustration and do not represent the only implementation manner.

[0036] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the technical field to which this application belongs. The terms used in the specification of this application are for the purpose of describing specific embodiments only and are not intended to limit this application. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0037] As Figures 1 to 5 shown, the present invention provides a downhole drill string pushing device, which includes a tool outer cylinder 2. A worm shaft 6 is arranged inside the tool outer cylinder 2. An axially penetrating worm shaft central hole is arranged on the worm shaft 6. The worm shaft central hole is arranged with a large diameter, fully meeting the circulation of drilling fluid and effectively reducing the pressure loss of the flowing drilling fluid. A rolling wheel structure 4 symmetrically arranged radially is provided on the side wall of the tool outer cylinder 2. The rolling wheel structure 4 includes a rolling wheel 43 that can mesh with the worm shaft 6. The outer wall of the rolling wheel 43 can abut against the well wall. The worm shaft 6 drives the rolling wheel 43 to rotate so that the rolling wheel 43 interacts with the well wall to generate a forward thrust (extra thrust), and this forward thrust can actively pull the drill pipe string (prior art) and push it forward. At least a pair of forward wheel structures 3 symmetrically arranged radially are provided on the side wall of the tool outer cylinder 2. The forward wheel structure 3 includes a forward wheel 31 that can contact the well wall. The outer shape of the forward wheel 31 is arranged in a parabola to reduce the friction coefficient of the pipe string. The outer shape of the forward wheel 31 is arranged in a parabola, which can reduce the contact area with the well wall and reduce the friction between the pipe string and the well wall in directional wells and horizontal wellbores.

[0038] The downhole drill string pushing device of the present invention can be installed around the downhole motor drill or between drill pipes, and can also be installed in series to further increase the thrust.

[0039] In the downhole drill string pushing device of the present invention, the forward wheel structure can effectively reduce the friction coefficient of the pipe string. The rolling wheel structure interacts with the well wall to generate an extra thrust and actively pulls the drill pipe string. A large-diameter drilling fluid circulation channel is reserved inside the worm shaft, reducing the pressure loss of the flowing drilling fluid. The downhole drill string pushing device of the present invention has a simple structure, fewer components, strong reliability, and can also increase the pulling force by being used in series to meet the requirement of greatly increasing the wellbore extension limit.

[0040] Furthermore, as Figure 1 、 Figure 2 、 Figure 3 、 Figure 5 shown, the central axis of the rolling wheel 43 is arranged parallel to the central axis of the tool outer cylinder 2. A strip-shaped thread is arranged on the outer wall of the rolling wheel. The strip-shaped thread can mesh with the worm shaft 6, and the outer wall of the strip-shaped thread can abut against the well wall.

[0041] Furthermore, as Figure 5As shown, rolling wheel mounting through slots 21 are radially symmetrically arranged on the side wall of the tool outer cylinder 2. Roller shaft hinge seats are respectively arranged at both axial ends of each rolling wheel mounting through slot 21. Roller shafts 44 are arranged at both ends of the rolling wheel, and the roller shafts 44 are hinged in the roller shaft hinge seats.

[0042] Further, as Figure 3 , Figure 5 shown, the roller shaft hinge seat includes a seat platform, a gland 41 and a first fixing pin 42. The seat platform is arranged at both axial ends of the rolling wheel mounting through slot. An arc-shaped groove is arranged on the seat platform. The gland 41 can be snap-connected to the seat platform, and the gland is detachably connected to the seat platform through the first fixing pin 42. In a specific embodiment of the present invention, two cover through holes are arranged on the gland 41, and the first fixing pin 42 passes through the cover through holes to connect the seat platform.

[0043] At one end of each roller shaft away from the strip thread, a convex ring 45 with an increasing diameter is arranged. At one end of the arc-shaped groove away from the strip thread, a clamping groove with an increasing diameter is arranged. The convex ring 45 can be rotatably arranged in the clamping groove to axially fix the rolling wheel.

[0044] Further, as Figure 1 , Figure 2 , Figure 3 , Figure 4 shown, each forward wheel structure 3 includes a forward wheel group. The forward wheel group includes a plurality of forward wheels 31 arranged in parallel at intervals. The central axis of each forward wheel is vertically arranged in space with the central axis of the tool outer cylinder, so that the tangential direction of the forward wheel is parallel to the central axis of the tool outer cylinder 2. Forward wheel shafts are respectively arranged at both axial ends of each forward wheel 31, and each forward wheel shaft is hinged on the tool outer cylinder 2.

[0045] Further, as Figure 3 , Figure 4 shown, forward wheel mounting through slots 22 are radially symmetrically arranged on the side wall of the tool outer cylinder 2. Each forward wheel 31 passes through the forward wheel mounting through slot 22; a first support plate 33 and a second support plate 34 are respectively arranged on both circumferential sides of the forward wheel mounting through slot 22. The forward wheel shafts at both ends of each forward wheel 31 are respectively hinged on the first support plate 33 and the second support plate 34.

[0046] Further, as Figure 3 , Figure 4 shown, a plurality of mounting shaft holes are respectively arranged on the first support plate 33 and the second support plate 34. Needle roller bearings 32 are arranged in each mounting shaft hole, and each forward wheel shaft is hinged in each needle roller bearing 32. In a specific embodiment of the present invention, 3 mounting shaft holes are machined in the middle of the first support plate 33; 3 mounting shaft holes are machined in the middle of the second support plate 34; needle roller bearings 32 are respectively installed in the 6 mounting shaft holes of the first support plate 33 and the second support plate 34.

[0047] Further, asFigure 3 , Figure 4 As shown, inner bosses are respectively arranged at both axial ends of the through groove 22 for mounting the forward wheels. Connecting through holes are respectively arranged inside each inner boss. Threaded connection holes are respectively arranged at both ends of the first support plate 33. Connecting through holes are respectively arranged at both ends of the second support plate 34. The connecting through holes, the connecting through holes and the threaded connection holes are penetrated by the second fixing pins 35. Each second fixing pin 35 fixedly connects the first support plate 33 and the second support plate 34 inside the through groove for mounting the forward wheels.

[0048] Furthermore, as Figure 1 , Figure 3 shown, in this embodiment, two pairs of forward wheel structures 3 are arranged on the side wall of the tool outer cylinder 2. The two pairs of forward wheel structures 3 are arranged at intervals along the axial direction of the tool outer cylinder, and the two pairs of forward wheel structures are arranged in a circumferential stagger of 90°. One pair of forward wheel structures 3 is arranged beside the rolling wheel structure 4. The forward wheel structure 3 and the rolling wheel structure 4 are arranged in a circumferential stagger and evenly. The two pairs of forward wheel structures 3 can ensure that there is always a forward wheel in contact with the lower well wall during the directional and horizontal drilling processes, ensuring the effect of reducing friction.

[0049] Furthermore, as Figure 1 , Figure 3 shown, connectors 1 are respectively connected to both ends of the tool outer cylinder 2. Both ends of the worm shaft are hermetically connected to the connector 1 by threads. The connector 1 can be hermetically connected to the drive shaft or the drill pipe string by a coupling (prior art). An axially penetrating connector central hole is arranged on the connector. The connector central hole communicates with the worm shaft central hole to form a drilling fluid circulation channel; limiting shoulders are arranged at both axial ends of the worm shaft 6. The limiting shoulders are connected to the tool outer cylinder 2 in cooperation through thrust bearings.

[0050] As Figure 6 shown, when the downhole drill tool pushing device of the present invention works downhole, the connector 1 at one end of the worm shaft 6 is connected to the output end of the power mechanism through a coupling (prior art, the power mechanism includes but is not limited to turbines, screws or electric mechanisms). The connector 1 at the other end of the worm shaft 6 is connected in series with the forward mechanism through a coupling or connected to the drill string by threads. When horizontal well and directional well drilling are carried out in the formation 7, driven by the output end of the power mechanism (prior art), the connector 1 drives the worm shaft 6 to rotate clockwise around the wellbore axis, and then drives the rolling wheel 43 to rotate counterclockwise. The strip thread of the rolling wheel 43 and the well wall of the wellbore 8 interact to generate an additional forward thrust, providing forward power for the forward wheel 31, enabling the downhole drill string to advance smoothly. The downhole drill tool pushing device of the present invention can reduce the friction of the pipe string and actively pull the drill pipe string at the same time, providing a drilling pressure for the drill bit and greatly improving the drilling speed.

[0051] As described above, the downhole drill tool pushing device of the present invention has the following beneficial effects:

[0052] In the downhole drill string propulsion device of the present invention, the forward wheel structure can effectively reduce the pipe string friction coefficient. The rolling wheel structure interacts with the wellbore wall to generate an additional thrust force to actively pull the drill pipe string. A large-diameter drilling fluid circulation channel is reserved inside the worm shaft, reducing the pressure loss of the flowing drilling fluid. In the downhole drill string propulsion device of the present invention, the two pairs of forward wheel structures can ensure that there is always one forward wheel in contact with the lower wellbore wall during directional and horizontal drilling, ensuring the effect of reducing friction. The downhole drill string propulsion device of the present invention has a simple structure, fewer components, and strong reliability. It can also increase the pulling force by being used in series to meet the requirement of greatly improving the wellbore extension limit.

[0053] The above description is only a schematic specific embodiment of the present invention and is not intended to limit the scope of the present invention. Any equivalent changes and modifications made by those skilled in the art without departing from the concept and principles of the present invention shall fall within the scope of protection of the present invention.

Claims

1. A downhole drill string pushing device, comprising a tool outer barrel, characterized in that, A worm shaft is arranged inside the outer cylinder of the tool, and an axially penetrating central hole of the worm shaft is arranged on the worm shaft; rolling wheel structures are radially symmetrically arranged on the side wall of the outer cylinder of the tool. The rolling wheel structure includes a rolling wheel that can mesh with the worm shaft. The outer wall of the rolling wheel can abut against the wellbore wall. The worm shaft drives the rolling wheel to rotate so that the rolling wheel and the wellbore wall interact to generate a forward thrust; at least a pair of forward wheel structures that are radially symmetrically arranged are arranged on the side wall of the outer cylinder of the tool. The forward wheel structure includes a forward wheel that can contact the wellbore wall. The outer shape of the forward wheel is arranged in a parabola to reduce the pipe string friction coefficient; The central axis of the rolling wheel is arranged parallel to the central axis of the outer cylinder of the tool. A strip-shaped thread is arranged on the outer wall of the rolling wheel. The strip-shaped thread can mesh with the worm shaft, and the outer wall of the strip-shaped thread can abut against the wellbore wall; Rolling wheel installation through grooves are radially symmetrically arranged on the side wall of the outer cylinder of the tool. Roller shaft hinge seats are respectively arranged at both axial ends of each rolling wheel installation through groove. Roller shafts are arranged at both ends of the rolling wheel, and the roller shafts are hinged in the roller shaft hinge seats; The roller shaft hinge seat includes a seat platform, a gland and a first fixing pin. The seat platform is arranged at both axial ends of the rolling wheel installation through groove. An arc-shaped groove is arranged on the seat platform. The gland can be buckled and connected to the seat platform. The gland is detachably connected to the seat platform through the first fixing pin; a convex ring with an increasing diameter is arranged at one end of each roller shaft away from the strip-shaped thread. A clamping groove with an increasing diameter is arranged at one end of the arc-shaped groove away from the strip-shaped thread. The convex ring can be rotatably arranged in the clamping groove to axially fix the rolling wheel; Each forward wheel structure includes a forward wheel group. The forward wheel group includes a plurality of forward wheels arranged in parallel at intervals. The central axis of each forward wheel is arranged perpendicular to the central axis of the outer cylinder of the tool in space; forward wheel shafts are respectively arranged at both axial ends of each forward wheel, and each forward wheel shaft is hinged on the outer cylinder of the tool.

2. The downhole drill tool pushing device according to claim 1, wherein, Forward wheel installation through grooves are radially symmetrically arranged on the side wall of the outer cylinder of the tool. Each forward wheel passes through the forward wheel installation through groove; a first support plate and a second support plate are respectively arranged on both circumferential sides of the forward wheel installation through groove. The forward wheel shafts at both ends of each forward wheel are respectively hinged on the first support plate and the second support plate.

3. The downhole drill tool pushing device according to claim 2, characterized in that, A plurality of installation shaft holes are respectively arranged on the first support plate and the second support plate. Needle bearings are arranged in each installation shaft hole, and each forward wheel shaft is hinged in each needle bearing.

4. The downhole drill tool pushing device according to claim 2, characterized in that, Inner bosses are respectively arranged at both axial ends of each forward wheel installation through groove. Connecting through holes are respectively arranged in the inner bosses. Threaded connection holes are respectively arranged at both ends of the first support plate. Connecting through holes are respectively arranged at both ends of the second support plate. The connecting through holes, the connecting through holes and the threaded connection holes penetrate through second fixing pins, and each second fixing pin fixedly connects the first support plate and the second support plate in the forward wheel installation through groove.

5. The downhole drill tool driving device according to claim 1, characterized in that Two pairs of the forward wheel structures are arranged on the side wall of the tool outer cylinder, the two pairs of the forward wheel structures are arranged at intervals along the axial direction of the tool outer cylinder, and the two pairs of the forward wheel structures are arranged in a circumferential stagger of 90°.

6. The downhole drill tool pushing device according to claim 1, wherein, Connectors are respectively connected to both ends of the tool outer cylinder, an axially penetrating connector central hole is arranged on the connector, and the connector central hole is communicated with the worm shaft central hole to form a drilling fluid circulation channel; limiting shoulders are arranged at both axial ends of the worm shaft, and the limiting shoulders are connected with the tool outer cylinder in a matching manner through thrust bearings.

Images