JP4770846B2 - Oil well pipe coupling mounting device - Google Patents

Description

  The present invention relates to an oil well pipe coupling attachment device for attaching a special screw coupling to a pipe end of an oil well pipe.

In recent years, the number of shallow wells and gas wells that are easy to develop has decreased, and the number of deep wells exposed to high temperature and pressure has increased. In addition to the vertical excavation, well excavation methods such as inclined excavation or horizontal excavation have been adopted due to the advancement of excavation technology.
With such changes in the usage environment, requirements for sealing performance for oil well pipe couplings have become increasingly severe. For example, a special screw coupling K having a shape as shown in FIG. 6 is known (Patent Document 1). This special thread coupling K has a square taper threaded part a that is screwed with the threaded part of the pipe end W1 of the oil well pipe W on both sides of the ring-shaped parallel part d in order to exhibit sealing performance, and the subsequent corners. It has a part b and a shoulder part c.

  The ring-shaped parallel part d is formed to have the same dimension as the inner diameter D of the oil well pipe W to which it is attached on the inner surface in the axial direction center part when the coupling is manufactured. Moreover, the clearance g1 between the square taper thread part a of the pipe end W1 of the oil well pipe W and the square taper thread part a screwed to it is as shown in FIG. It is formed so as to be smaller than the clearance g2 between the taper screw portions (FIG. 7B). The shape of this round taper thread is determined by API.

  FIG. 8 shows the oil well pipe coupling attachment process and subsequent steps. (A) is a coupling attachment step of attaching the special screw coupling K to the pipe end W1 of the oil well pipe W, (b) is a subsequent mechanical fastening step of fastening the special screw coupling K with a predetermined fastening torque, ( c) is a protector plug attachment process for attaching the protector plugs J1 and J2 to protect the thread portion.

  Here, in the case of a special screw coupling K having a square taper screw portion a and a ring-shaped parallel portion d on the inner surface in the axial direction, the clearance g1 between the taper screw portions is a conventional round-shaped clearance g2. Smaller than For this reason, in the coupling attachment process of attaching the special screw coupling K to the pipe end W1 of the oil well pipe W, the coupling center K0 and the pipe axis W0 can be prevented from failing to be screwed between the first square taper thread portions. The range of the angle θ formed by is reduced (see FIG. 9). Due to this, the coupling failure rate of the special screw coupling K is higher than that of the conventional round-shaped screw part, and automation has not been achieved.

Therefore, the work of attaching the special screw coupling to the end of the oil well pipe has to be performed manually as shown in FIG. 10 (a) and 10 (b), reference numeral 8 denotes a foot switch for rotating the turning roller 7 or stopping the rotation of the turning roller 7.
That is, FIG. 10A shows a state in which the rotation of the turning roller 7 is stopped and the first square taper screw parts are carefully screwed together by human power, and FIG. The state where the turning roller 7 is rotated while the special screw coupling K is held and the subsequent square taper screw portions are screwed together is shown.

In order to attach the special screw coupling to the pipe end W1 of the oil well pipe W in this way, it is necessary to prevent the first square taper thread portions from being poorly engaged by human power.
Therefore, if the coupling attachment process of the special screw coupling K can be automated, the subsequent mechanical tightening process and protector plug attachment process have already been automated, so that manual labor is eliminated.

By the way, Patent Document 2 discloses a pipe coupling mounting device for tightening a coupling attached to a pipe to such an extent that it can be easily removed by human power.
JP 2003-74763 A Japanese Patent Laid-Open No. 11-230435

  However, the coupling mounting device described in Patent Document 2 is a mounting device that tightens the coupling to such an extent that it can be easily removed by human power in the mechanical tightening step of FIG. 10B described above. In the step of attaching the special screw coupling of 10 (a) to the pipe end of the oil well pipe, the problem that the first square taper threaded portions cannot be prevented from being screwed together is still unsolved and remains a problem.

  The present invention solves the above-mentioned problems of the prior art, and when attaching a special thread coupling to the pipe end of the oil well pipe, it is possible to prevent the first square taper screw parts from being poorly engaged and to reduce the coupling installation failure rate. An object of the present invention is to propose a coupling attachment device for an oil well pipe that can be lowered.

  As a result of earnestly examining the coupling mounting device for oil well pipes that can prevent the poor engagement of the first square taper thread portions, even when the special screw coupling K is heavy, the inventor has established the coupling center and the axis of the rotating shaft. If the special screw coupling can be clamped in a state where the angle formed by the core is within the allowable angle, it has been found that the first square taper screw portions can be prevented from being poorly engaged, and the present invention is made based on this knowledge. It came to.

That is, the present invention is as follows.
1. A device that attaches a special screw coupling to the pipe end of an oil well pipe, which can be replaced according to the outer diameter of the special screw coupling and the main body that can be moved forward and backward with respect to the pipe end of the oil well pipe. A arbor mounted on the apparatus main body and capable of rotating in a state where the outer diameter portion of the special screw coupling is clamped, and a ring shape protruding from the inner surface of the special screw coupling on the front side of the arbor An oil well pipe coupling mounting device is provided, wherein a centering jig for centering the special screw coupling is provided by receiving the parallel portion of the special screw coupling.
2. The centering jig is replaceably fixed to the frustoconical member of the arbor with a lock nut. The coupling mounting device for oil well pipes as described in 2.
3. In addition to the centering jig, an end surface pusher for pressing the end surface of the special screw coupling on the opposite side of the centering jig is provided. Or 2. The coupling mounting device for oil well pipes as described in 2.

  According to the oil well pipe coupling mounting device of the present invention, since a centering jig is provided on the front side of the arbor, the ring-shaped parallel portion protruding from the inner surface of the special screw coupling is centered. The special screw coupling can be centered by receiving it on the outer peripheral surface of the jig. For this reason, even when the special screw coupling K is heavy, when the special screw coupling is attached to the pipe end of the oil well pipe, the special screw cup is kept with the angle between the coupling center and the axis of the rotating shaft within the allowable angle. The ring can be clamped.

  Accordingly, when the special screw coupling is rotated and advanced toward the pipe end of the oil well pipe, it is possible to prevent the first square taper screw portions from being poorly engaged with each other and to reduce the coupling attachment failure rate.

Hereinafter, an oil well pipe coupling mounting device of the present invention will be described in detail with reference to the drawings.
FIG. 1A is a side view showing a coupling mounting device for an oil well pipe according to an example of the present invention, and FIG. 1B is an explanatory view of the operation of a centering jig 2. FIG. 2 is a side view showing a state before the special screw coupling K is clamped by the oil well pipe coupling mounting device of the example of the present invention.
The oil well pipe coupling mounting device according to the present invention includes an apparatus main body 4 that can be moved forward and backward with respect to the pipe end W1 of the oil well pipe W, and an arbor that can be rotated with the outer diameter portion of the special screw coupling K clamped. 1 is provided. The arbor 1 is mounted on the apparatus main body 4 so as to be replaceable according to the outer diameter size of the special screw coupling K. Further, on the front side of the arbor 1, as shown in detail in FIG. 1 (b), by receiving a ring-shaped parallel portion d protruding from the inner surface of the special screw coupling K on the outer peripheral surface, A centering jig 2 for centering the special screw coupling K is provided.

Accordingly, even when the special screw coupling K is heavy when the coupling is attached, the coupling center K0 and the shaft core 3a of the rotary shaft 3 are arranged by the centering jig 2 as shown in FIG. The outer diameter portion of the special screw coupling K can be clamped by the arbor 1 with the angle α formed by
As shown in FIGS. 1A and 1B, the centering jig 2 is arranged coaxially with the rotary shaft 3 protruding from the rear surface side.

Here, the permissible angle is an angle formed by the coupling center K0 and the tube axis W0 that can prevent a screwing failure between the first rectangular taper thread portions, and is determined by geometric calculation or experiment. Can do. In the case of a seamless steel pipe having a pipe outer diameter of 60.3 to 177.8 mm, the allowable angle is 1.0 degree.
In order to rotate the arbor 1 at a predetermined rotational speed after clamping the outer diameter portion of the special screw coupling K with the arbor 1, the motor (not shown) is rotated and the rotary shaft 3 connected to the motor is rotated at the predetermined rotational speed. And it is sufficient. Further, in order to move the arbor 1 forward and backward with respect to the pipe end W1 of the oil well pipe W, the apparatus main body 4 arranged coaxially with the pipe axis W0 is operated by a moving means (not shown) such as an air cylinder.

  In this way, as shown in FIGS. 1A and 1B, when the special screw coupling is rotated and advanced toward the pipe end W1 of the oil well pipe W, the centering jig 2 is used. As a result, the swivel angle of the angle α formed by the coupling center K0 and the shaft core 3a of the rotary shaft 3 is within the allowable angle, so that the first square taper screw portions can be prevented from being poorly engaged and the coupling installation failure rate is reduced. be able to.

  On the other hand, FIGS. 5A and 5B show defects in the case of the conventional example in which the centering jig 2 is not provided on the front side of the arbor 1. In the conventional oil well pipe coupling mounting device, when the special screw coupling K is heavy at the time of coupling mounting, the angle β formed by the coupling center K0 and the shaft core 3a of the rotating shaft 3 is β> allowable angle. Become. For this reason, since the angle β formed by the coupling center K0 and the shaft core 3a of the rotating shaft 3 exceeds the allowable angle, the first square taper thread portions are likely to be poorly engaged with each other.

By the way, the arbor 1 used in the present invention can cope with the outer diameter size of the special screw coupling K within a predetermined range. When the arbor is out of the predetermined range, the arbor 1 has the centering jig 2 on the front side and the rear side. The arbor 1 having the rotating shaft 3 is exchanged for one that can cope with the outer diameter size.
In the present invention, in addition to the centering jig 2 described above, it is preferable that an end face pusher 5 for pressing the end face of the special screw coupling K on the opposite side of the centering jig 2 is provided. When such an end face pusher 5 is provided, the mounted special screw coupling K is moved by the push cylinder 6 in the push direction 9 as shown in FIG. The front surface can be surely reached.

Next, when the special screw coupling K reaches the front surface of the arbor 1, the arbor 1 is advanced relative to the frustoconical member 11 from the standby position of the arbor 1 shown in FIG. As shown in FIG. 4, the arbor 1 can be clamped between the arbor 1 and the frustoconical member 11 according to the outer diameter size of the special screw coupling K.
As shown in FIGS. 3 and 4, the arbor 1 has a cylindrical cup shape in which the centering jig 2 has a storage space for the lock nut 2a on the front side, and the frustoconical member 11 of the arbor by the lock nut 2a. It is preferable to have a structure that is fixed to be exchangeable. This is because the centering jig 2 having an appropriate outer diameter can be mounted according to the inner diameter D of the oil well pipe.

FIG. 3A is a cross-sectional view showing the internal structure of the arbor of the embodiment, and shows the standby state of the arbor 1. FIG. 3B is a front view thereof. 4 is a cross-sectional view showing a state where the special screw coupling K is clamped by the arbor 1 shown in FIG.
Further, in the present invention example, it is preferable that an adjusting device is provided for adjusting the pressing pressure when the square taper screw portions come into contact with each other when the special screw coupling K is attached to the pipe end of the oil well pipe.

  The reason for this is that if the adjusting device is provided, the pressure when the first square taper screw parts are screwed together can be set appropriately, and this is combined with the operation and effect of the centering jig 2 described above. This is because the coupling attachment failure rate can be further reduced.

(A) is a side view which shows the coupling attachment apparatus for oil well pipes of the example of this invention, (b) is explanatory drawing of the effect | action of the centering jig | tool. It is a side view which shows the state before clamping a special screw coupling with the coupling attachment apparatus for oil well pipes of the example of this invention. (A) is sectional drawing which shows the standby state of the arbor of an Example, (b) is the front view. It is sectional drawing which shows the state which clamped the special thread coupling of the minimum outer diameter with the arbor shown in FIG. (A) is a side view which shows the coupling attachment apparatus for oil well pipes of a prior art example, (b) is a side view explaining the malfunction at the time of clamping a special screw coupling with the arbor of a prior art example. It is sectional drawing which shows an example of a special screw coupling. (A) is principal part sectional drawing which shows the clearance between square taper screw parts, (b) is principal part sectional drawing which shows the clearance between round taper screw parts. It is a perspective view explaining the coupling attachment process after an oil well pipe. It is a perspective view which shows angle (theta) which the coupling center at the time of coupling attachment and a pipe axis make. (A), (b) is a perspective view which shows the conventional attachment method of a special screw coupling.

Explanation of symbols

W Oil well pipe W0 Pipe shaft W1, W2 Pipe end D Oil well pipe inner diameter K Special screw coupling K0 Coupling center a Taper screw part b Corner part c Shoulder part d Parallel part g1, g2 Clearance J1, J2 Protector plug θ Coupling Angles between the center and the tube axis α, β Angles between the coupling center and the axis of the rotating shaft 1 Arbor 2 Centering jig 2a Lock nut 3 Rotating shaft 3a Rotating shaft axis 4 Device body 5 End face pusher 6 Push cylinder 7 Turning roller 8 Foot switch 9 Push direction
10 Direction of rotation
11 frustoconical member

Claims (3)

A device that attaches a special screw coupling to the pipe end of an oil well pipe, which can be replaced according to the outer diameter of the special screw coupling and the main body that can be moved forward and backward with respect to the pipe end of the oil well pipe. A arbor mounted on the apparatus main body and capable of rotating in a state where the outer diameter portion of the special screw coupling is clamped, and a ring shape protruding from the inner surface of the special screw coupling on the front side of the arbor An oil well pipe coupling mounting device is provided, wherein a centering jig for centering the special screw coupling is provided by receiving the parallel portion of the special screw coupling. 2. The oil well pipe coupling mounting device according to claim 1, wherein the centering jig is fixed to a frustoconical member of the arbor in a replaceable manner with a lock nut. The oil well pipe cup according to claim 1 or 2, further comprising an end surface pusher for pressing an end surface of the special screw coupling on the opposite side of the centering jig in addition to the centering jig. Ring mounting device.

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