CN212837629U

CN212837629U - Friction device for stabilizing screw rod during well drilling

Info

Publication number: CN212837629U
Application number: CN202021044126.6U
Authority: CN
Inventors: 郑德帅; 赵小祥; 何汉平; 李梦刚; 牛成成
Original assignee: China Petroleum and Chemical Corp; Sinopec Research Institute of Petroleum Engineering
Current assignee: China Petroleum and Chemical Corp; Sinopec Research Institute of Petroleum Engineering
Priority date: 2020-06-09
Filing date: 2020-06-09
Publication date: 2021-03-30
Anticipated expiration: 2030-06-09

Abstract

The utility model provides a friction device for stabilizing screw rod when well drilling mainly comprises the body of connection on the screw rod, install the control assembly in body center channel and install the thrust unit on the outer wall of body. Wherein the body comprises a central channel for the circulation of drilling fluid and radial communication holes. The control assembly includes a control valve body movable within the central passage with a gap between the control valve body and the central passage of the body. The thrust unit comprises a motherboard mounted on the outer surface of the body, a thrust member hinged to the motherboard and capable of rotating around an axis, and a piston capable of interacting with the thrust member.

Description

Friction device for stabilizing screw rod during well drilling

Technical Field

The utility model relates to a friction device for stabilizing screw rod when well drilling.

Background

When directional drilling is performed, it is first necessary to adjust the progressive cavity tool face angle to the design angle. However, the reaction torque of the screw drilling tool is in a vibration state, and the elasticity of a drill string of thousands of meters is extremely high, so that great and unstable friction force is generated between the drill string and a well wall, and therefore, a tool face angle is unstable after being adjusted to a design angle, and the deflecting efficiency is seriously influenced.

In order to solve the problem, the main solving means at present is to reduce the friction force between a drill string and a well wall and reduce the reaction torque of a screw drilling tool.

To reduce the friction between the drill string and the borehole wall, changes to the top drive are currently made. When the sliding drill is used for drilling, the top drive firstly rotates forwards for a certain number of turns and then rotates backwards for the same number of turns, and the process of reciprocating continuously is continued, so that the drill string is subjected to continuous positive and negative oscillation action under the condition, and the friction force between the drill string and the well wall is reduced. However, in this solution, the length of oscillation is limited and there is a risk of shackle breaking.

In addition, the patent named "hydraulic oscillator for drilling" provides a system consisting of a power section, a valve shaft section and an oscillating nipple section. In the system, a conventional downhole power tool is combined with a special valve, so that the kinetic energy of drilling fluid is converted into vibration mechanical energy along the axial direction of the drilling tool, and therefore, the conventional rotary rock breaking mode is changed into rotary rock breaking with soft and variable drilling pressure, so that the drilling tool and a well wall are in a dynamic friction state, the friction force between the drilling tool and the well wall is reduced, and the rock breaking efficiency is improved. However, the solution has a small influence range, the integral resistance reduction effect is not obvious, and the hydraulic pressure consumption is large.

In order to reduce the reaction torque of the screw drilling tool, a drill bit with low rock breaking torque can be selected at present. Generally, the rock breaking torque of the multi-blade PDC drill bit and the roller bit used at present is lower, but the low rock breaking torque drill bit is usually low in mechanical rotating speed, so that the drilling efficiency is low, and the drilling cost is improved.

SUMMERY OF THE UTILITY MODEL

The utility model aims at providing a friction device for stabilizing screw rod when well drilling reduces the reaction torque of screw rod drilling tool, the stability of screw rod when improving the well drilling to reach the instrument face of stabilizing the screw rod, improve the purpose of syncline efficiency.

According to the utility model discloses, a friction device for stabilizing screw rod when well drilling is provided, include: the body is connected to the screw and comprises a central channel for the circulation of drilling fluid and radial communication holes. And a control assembly mounted within the central passage, the control assembly including a control valve body movable within the central passage with a gap between the control valve body and the central passage. In addition, there is a thrust unit mounted on the outer wall of the body, the thrust unit including a motherboard mounted on the outer surface of the body, a thrust member hinged to the motherboard and capable of pivoting, and a piston capable of interacting with the thrust member. Wherein the control valve body has a first position in which communication between the central passage and the communication hole is cut off, and is axially movable to a second position under a force greater than a predetermined displacement of drilling fluid, thereby establishing communication between the central passage and the communication hole via the gap. Such that the piston is urged by the drilling fluid when the control valve body is in the second position, thereby causing the thrust member to pivot outwardly into engagement with the borehole wall.

In a preferred embodiment, the control assembly includes a resilient member having a spring force equal to the force of the predetermined displacement of drilling fluid to hold the control valve body in the first position if drilling fluid is less than the predetermined displacement.

In a preferred embodiment, the control valve body is provided on its outer circumference with a first sealing ring close to the elastic element and a second sealing ring remote from the elastic element, wherein both the first and the second sealing ring seal the gap when the control valve body is in the first position and only the second sealing ring seals the gap when the control valve body is in the second position.

In a preferred embodiment, the central passage has a step, the control valve body is configured as a stepped shaft, and the first and second seal rings are each provided on the small diameter portion of the control valve body and are divided in the axial direction on both sides of the communication hole.

In a preferred embodiment, a first groove is formed in an outer wall of the body, and the motherboard is disposed in the first groove. A second groove communicating with the communication hole is provided in a bottom surface of the first groove, and the mother plate is provided with a through-hole such that the piston is accommodated in a piston chamber constituted by the through-hole and the second groove.

In a preferred embodiment, two ends of the first groove are respectively provided with a buffer block, so that the motherboard and the thrust piece are clamped between the buffer blocks.

In a preferred embodiment, the free outer end surface of the thrust piece is configured into a convex arc surface, the contact surface of the sand blocking strip and the thrust piece is configured into a corresponding concave arc surface, and the sand blocking strip is kept in close contact with the free outer end surface of the thrust piece.

In a preferred embodiment, three thrust units are arranged on the friction device, which are distributed uniformly in the circumferential direction.

In a preferred embodiment, a blocking member is provided in the central passage, and the elastic member is provided between the blocking member and the control valve body.

According to the utility model discloses a friction device can make the thrust piece outwards stretch out and think into the joint between with the wall of a well when drilling fluid flow is higher than the specified value to produce frictional force, restrict the vibrations or the pivoting of screw rod from this, reach the purpose of stabilizing the screw rod instrument face and improving the efficiency of deflecting.

Drawings

The invention will be described in detail below with reference to the attached drawings, in which:

fig. 1 is an axial sectional view of the friction device of the present invention.

Fig. 2 is a radial cross-sectional view of the friction device shown in fig. 1.

Fig. 3 is a partially enlarged view of fig. 2.

In the present application, the drawings are all schematic and are used only for illustrating the principles of the invention and are not drawn to scale.

Detailed Description

The present invention will be described in detail with reference to the accompanying drawings.

Fig. 1 shows a friction device 100 according to an embodiment of the invention. As shown in fig. 1, the friction device 100 includes a body 10 connected to a screw. The body 10 is a hollow tubular device provided with a male connection button 14 and a female connection button 16 at both ends for connection with a threaded rod and a drill string (neither shown), respectively. A central passage 15 for the drilling fluid is provided in the interior of the body 10. A stepped hole is provided in the passage 15 so as to divide the central passage 15 into two portions, namely a large diameter portion 17 having a larger diameter near the downstream end (i.e., the left end in fig. 1) and a small diameter portion 18 having a smaller diameter near the upstream end (i.e., the right end in fig. 1). It will be readily appreciated that this stepped face of the passage 15 may be provided with a chamfered transition.

According to the present invention, the friction device 100 comprises a control assembly 20 mounted in the body 10. The control assembly 20 includes a control valve body 22, a spring 24 attached at one end to the control valve 22, and a spring retainer 26 attached at the other end of the spring. Wherein the control valve body 22 is configured in the shape of a hollow stepped shaft and is provided at a stepped region of the central passage 15 of the body 10.

The diameter of the control valve body 22 should be smaller than the diameter of the central passage 15. In one example, the large diameter portion of the control valve body 22 is configured to be 0.2mm smaller than the large diameter portion of the central passage of the body 10, while the small diameter portion of the control valve body 22 is configured to be 0.1mm smaller than the small diameter portion of the central passage of the body 10. In this way, a gap 25 is formed between the inner wall of the central passage 15 of the body 10 and the outer wall of the control valve body 22 to facilitate movement of the control valve body 22 within the central passage 15 of the body 10. In addition, two

seal rings

28 and 29 are mounted on the outer wall of the small diameter portion of the control valve body 22 to seal the gap 25 between the central passage 15 of the body 10 and the small diameter portion 18 of the control valve body 22.

As shown in fig. 1, a spring 22 is disposed in the large diameter portion 17 of the central passage of the body 10, and one end abuts the control valve body 22. A spring stop 26 is mounted at the other end of the spring 24 and is threadably connected to the central passage 15 of the body 10, for example. The primary function of the snap ring 26 is to secure the spring 24. The control valve body 22 is thereby able to move axially under the impact of the drilling fluid from upstream and the spring force of the spring 24. This will be described in detail below.

According to the present invention, the friction device 100 further comprises a plurality of thrust units 50 provided on the body 10. As shown in fig. 2, the friction device 100 according to the present embodiment includes three thrust units 50 arranged at even intervals in the circumferential direction. The three thrust units 50 are identical in construction and will therefore be described hereinafter with reference to only one of them.

As shown in fig. 1, a first groove 32 is provided on an outer wall of the body, in which a mother board 52 is fixedly mounted by bolts. A second groove 34 is provided on the bottom surface of the first groove 32. A through hole 42 is provided on the mother board 52 at a position corresponding to the second groove 34. The through bore 42 and the second recess 34 together define a piston chamber in which a piston 54 (described below) is received.

In one example, the diameter of the through hole 42 is smaller than the diameter of the second groove 34, preferably 5mm smaller. In addition, a hole 44 is provided at the bottom of the second groove 34 so that the second groove 34 communicates with the above gap 25. As shown in fig. 1, the bore 44 is axially between the seal rings 28 and 29. Thus, in the condition shown in fig. 1, no drilling fluid enters the second recess 34 through the bore 44, since the sealing rings 28 and 29 each seal the gap 25 between the central passage 15 of the body 10 and the small diameter portion 18 of the control valve body 22.

The piston 54 may be stepped, for example, so that the upper end has a small diameter and the lower end has a large diameter, and the top may be formed in a hemispherical shape. The diameter of the lower end of the piston 54 is larger than the inner diameter of the through bore 42 so that the larger diameter portion of the piston 34 is positioned and prevented from being jacked down into the well when the clearance between the well wall and the friction device 100 is too large. Preferably, the second groove 34 may be sealed by a sealing ring at an outer wall of the lower large diameter portion of the piston 54.

Above the piston 54, a thrust piece 56 is provided. The free outer end face of the thrust piece 56 may be configured, for example, as a convexly curved face. Preferably, a spherical indentation is provided in the contact surface of the thrust member 56 with the piston 54, which forms a mating contact with the hemispherical top of the piston 54.

As shown in fig. 2, a through hole 46 is formed at the left end of the thrust member 36, and a mounting pin is provided in the through hole 46 and connected to a motherboard 52. In this way, the thrust member 56 is rotatable about the pin through a limited angle under the force provided by the piston 54. That is, the thrust member 56 is rotatably extended outward from the retracted state shown in fig. 2 to be in the extended state (not shown).

As shown in fig. 1, a pair of buffer blocks 40 are further disposed in the first recess 32, and are located at both ends of the first recess 32 to sandwich the motherboard 52 and the thrust member 56 for positioning function. In the illustrated embodiment, the upper portion of the bumper 40 may be machined in a right trapezoid shape with a hardened surface. Thus, the bumper 40 reduces friction between the friction device 100 and the borehole wall as the friction device 100 moves axially within the borehole wall, while protecting the thrust member 56.

As shown in fig. 3, the thrust member 36 is further provided with a sand bar 58 at an end away from the pin. The sand bar 58 is configured in a generally "L" shape. The contact surface 62 of the sand bar 58 with the thrust piece 56 is configured as a concave arc surface. When the thrust piece 56 is extended in a rotating mode, the free outer end face 65 of the thrust piece 56 is matched with the contact face 62 of the sand blocking strip 58, the two faces are guaranteed to be in close contact all the time, and therefore sand grains and sundries are prevented from falling into the space between the thrust piece 56 and the mother plate 52.

Although the friction device 100 according to this embodiment of the present invention includes three thrust units 50, it is easily understood that a different number of thrust units 50 may be installed as needed to meet practical requirements. In addition, the motherboard 52 in each thrust unit is also easy to install and remove, so that thrust pieces with different sizes can be installed according to the diameter of the well wall.

The operation of the friction device 100 according to the present invention is briefly described below.

After normal drilling, judging whether directional drilling is needed according to the track condition of the well. If directional drilling is required, the screw toolface angle is first adjusted to the design angle during drilling, then the rotary table is locked, and the drilling fluid displacement is adjusted to be higher than a specific displacement. At this point, the drilling fluid pressure is greater than the spring force and the spring 26 is compressed. In this condition, the control valve body 22 is moved from the first position shown in FIG. 1 to a second position (not shown) closer to the spring retainer 26 such that the sealing ring 28 adjacent the spring 24 is displaced from the small diameter portion 18 of the central passage 15 of the body 10 and is no longer sealed. The sealing ring 29, which is remote from the spring 26, still serves to seal the gap 25. Thus, drilling fluid may flow along the gap 25 and the through bore 34 at the bottom of the piston toward the piston 54, pushing the piston 54 upward. Thus, the thrust member 56 begins to extend rotationally under the thrust of the piston 54 until the thrust member 56 bears against the borehole wall. In this way, the entire friction device 100 is radially engaged with the borehole wall, thereby limiting the vibrations of the screw. In addition, when the screw rod has a rotation moment, a reverse friction force is generated between the thrust piece 56 and the well wall, so that the rotation moment is reduced or even counteracted, the effect of stabilizing the screw rod is achieved, and the deflecting efficiency during drilling is improved.

After a period of drilling, when the directional drilling is not needed according to the condition of the well track, the discharge capacity of the drilling fluid is reduced to be below the specific discharge capacity. At this point, the drilling fluid pressure is less than the spring force of the spring 26 and the control valve body 22 remains in the first position (i.e., the position shown in FIG. 1). Thus, the sealing rings 28 and 29 both function as seals. In this case, drilling fluid normally flows along the central passage 15 in the body 10 and no drilling fluid can enter the gap 25 to push the piston 54. Thus, the thrust member 56 remains in its initial, retracted state shown in FIG. 2, without contacting the borehole wall.

It will be readily appreciated that by setting the magnitude of the spring 26 spring force, a particular value of the drilling fluid flow rate at which the actuating thrust member 56 is extended can be controlled.

While the invention has been described with reference to a preferred embodiment, various modifications may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included within the protection scope of the present invention.

Claims

1. A friction device for stabilizing a screw while drilling, comprising:

a body connected with the screw rod, which comprises a central channel for the circulation of drilling fluid and a radial communicating hole,

a control assembly mounted within the central passage, the control assembly including a control valve body movable within the central passage with a gap between the control valve body and the central passage, an

A thrust unit mounted on an outer wall of the body, the thrust unit including a motherboard mounted on an outer surface of the body, a thrust piece hinged to the motherboard and capable of pivoting, and a piston capable of interacting with the thrust piece,

wherein the control valve body has a first position in which communication between the central passage and the communication hole is cut off, and is axially movable to a second position under a force of a drilling fluid larger than a predetermined displacement, thereby establishing communication between the central passage and the communication hole via the gap,

the piston is adapted to be urged by drilling fluid when the control valve body is in the second position, thereby causing the thrust member to pivot outwardly into engagement with the borehole wall.

2. A friction device, according to claim 1, characterized in that said control assembly comprises an elastic member having an elastic force equal to the force of said predetermined displacement of drilling fluid, so as to maintain said control valve body in the first position in the event that the drilling fluid is less than said predetermined displacement.

3. A friction device, according to claim 2, characterized in that a first sealing ring close to said elastic element and a second sealing ring remote from said elastic element are provided on the outer circumference of said control valve body, wherein both said first and second sealing rings seal said gap when said control valve body is in the first position, and only the second sealing ring seals said gap when said control valve body is in the second position.

4. A friction device, according to claim 3, characterized in that said central passage has a step, said control valve body is configured as a stepped shaft, said first and second sealing rings are both provided on a small diameter portion of said control valve body and are axially divided at both sides of said communication hole.

5. A friction device, according to any one of claims 1 to 4, characterized in that said body is provided on its outer wall with a first recess in which said mother plate is provided, in the bottom surface of which a second recess is provided communicating with said communication hole, and in that said mother plate is provided with a through hole, so that said piston is housed in a piston cavity constituted by said through hole and said second recess.

6. A friction device, according to claim 5, characterized in that a buffer block is provided at each end of said first recess, so as to sandwich said plate and thrust member between said buffer blocks.

7. A friction device, according to any of claims 1 to 4, characterized in that a sand bar is provided on said mother plate, said sand bar being held in close contact with the free outer end face of said thrust piece.

8. The friction device as recited in claim 7 wherein the free outer end surface of said thrust member is configured as a convex arc surface and the contact surface of said sand bar with said thrust member is configured as a corresponding concave arc surface.

9. A friction device, according to any one of claims 1 to 4, characterized in that three thrust units are provided, evenly distributed in the circumferential direction.

10. A friction device, according to any one of claims 2 to 4, characterized in that a blocking member is provided in said central passage, said elastic member being provided between said blocking member and said control valve body.