RU2354799C1 - Device for connection of drill pipes - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: invention is related to drill tool, namely, to devices for connection of drill pipes during rotary drilling of wells of different purpose. Mentioned result is achieved by the fact that device includes accessory in the form of lock nipple and coupling with thread, at the ends of which two ratchet semi-clutches are installed being rigidly connected to them, and their contact surfaces are arranged in the form of protrusions and their congruent cavities, for perception and transfer of torque moment simultaneously with threaded joint. Height of protrusions and cavities at every ratchet semi-clutch is defined from analytical expression: H=0.8 S / Z, where H is height of protrusion or cavity depth, S is thread pitch, Z is number of protrusions or cavities in every ratchet semi-clutch. Pitch of thread that joins lock nipples and coupling makes value that is equal to not more than j of its working part length. On internal surface of every ratchet semi-clutch there are through longitudinal grooves for installation of fixators in them, which are arranged in the form of L-shaped planks with springs, and width of planks is slightly less than width of through longitudinal grooves.

EFFECT: increased reliability with tight connection of drill pipes, and also prevention of their tightening against effect of considerable torsional forces that occur in process of well drilling.

4 cl, 5 dwg

Description

The invention relates to the mining industry, and in particular to devices for connecting drill pipes during rotary drilling of wells for various purposes, and can be used to connect other similar elements.

Known for the locking connection of drill augers, including a drill pipe, annular half-couplings fixed to its ends with an outer diameter equal to the diameter of the drill pipes, and with cam protrusions at the interaction ends and reciprocal depressions, and a shank with a lock located in the cavity of the coupling half, in which the lateral faces of the cam the couplings and their corresponding cavities, opposite to the working faces of the cam protrusions and reciprocal cavities, are made with an inclination, and the width of the peaks of the protrusions is less than the width of their base (RU No. 20177929, Cl. E21B 17/046, publ. 94.08.15).

The disadvantages of this connection of drill pipes are insufficient tightness and possible deformation of the cam protrusions during operation, leading to losses of the treatment agent when drilling deep wells and to the deformation of the cam protrusions and their jamming between themselves, which worsens the well drilling conditions and makes it difficult to disassemble and assemble the drill stand.

The closest in technical essence and the achieved result to the invention is a device for connecting drill pipes, including a device in the form of locking nipples and threaded couplings at the ends for connection with drill pipes and between each other (A.S. RU No. 17558202, Cl. ЕВВ 17 / 02, 17/04).

The disadvantages of this design include the significant structural complexity, insufficient reliability of the pipe connection when transmitting large axial loads and torques, which leads to deformation of the fasteners, loss of the connecting elements and ultimately to the separation of the pipe string, as well as insufficient sealing of the column with the ensuing negative consequences when drilling wells.

The expected technical effect of the use of the invention is to increase the reliability of the tight connection of drill pipes, as well as preventing them from being drawn in due to the significant torsional forces that arise when drilling wells.

The specified technical effect is achieved by the fact that in the device for connecting drill pipes, including a device in the form of locking nipples and a threaded sleeve for connecting to the drill pipes and between each other, at the ends of the locking nipple and coupling interacting with each other for transmission axial force from the drilling rig to the downhole tool, two ratchet half-couplings are rigidly connected to them, the contacting surfaces of which are made in the form of protrusions and grooves congruent to them for perception and per cottages torque simultaneously with the screw connection, and the height of projections and depressions on each ratchet coupling half is determined from the analytic expression

H = 0.8 S / Z,

where N is the height of the protrusion or the depth of the cavity,

S is the thread pitch

Z is the number of protrusions or depressions on each ratchet coupling half.

And also by the fact that the pitch of the thread connecting the locking nipple and the coupling to each other is equal to no more than 1/4 of the length of its working part.

And that. that on the inner surface of each ratchet coupling half there are through longitudinal grooves for placement of clamps in them.

And the fact that the latches are made in the form of L-shaped bars with springs. and the width of the slats is slightly less than the width of the through longitudinal grooves.

The invention is illustrated by drawings, where Fig. 1 shows a device in working position and its cross section along A-A, Fig. 2 shows a ratchet coupling half in section with a view along A, and Fig. 3 shows a latch with a leaf spring.

A device for connecting drill pipes consists of a locking nipple 1 with a thread 2, the step of which is not more than 1/4 of the length of its working part, for articulation with a similar thread on the pipes, the thread of the locking sleeve 3 (not shown in Fig. 1) for articulation with drill pipes. The thread pitch of 2 locking nipples and couplings, equal to not more than 1/4 of the length of the working part of their thread, guarantees a sufficient height, and therefore the strength of the protrusions and depressions of the ratchet coupling halves. At the ends of the nipple 1 and the coupling 3 on the thread side 2 with a step equal to not more than 1/4 of the length of its working part, the ratchet coupling halves 4 and 5 are rigidly mounted. The coupling 3 has a groove for accommodating the sealing ring 6, which ensures the tightness of the connection. Ratchet coupling halves 5 and 4 (see figure 2) are made with protrusions 7 and cavities congruent to them in shape 8, in contact with each other in the working position. On the inner surface of the ratchet coupling halves have longitudinal grooves 9, in which the clamps 10 are located, equipped with leaf springs 11, fixed to them with bolts 12. In the working position of the device, the grooves 9 are aligned relative to each other and latches 10 are inserted into them, preventing the pipe from turning when the need to use the reverse nominal rotation, and the leaf springs 11 provide reliable fastening of the latches 10 in the grooves 9 during operation of the device and do not create difficulties when assembling and disassembling.

The width of the latches 10 is slightly less than the width of the longitudinal grooves 9, which ensures their free entry into the longitudinal grooves 9 even with some non-alignment.

The height of the protrusions 7 and the depth of the depressions 8 are equal, are designated (H) and are determined from the analytical expression

H = 0.8 S / Z,

where S is the thread pitch 2,

Z is the number of projections 7 of the ratchet coupling half 5 or 4.

At such a height H, a guaranteed connection of the ratchet couplings 5 and 4 to the working position is ensured when screwing the locking nipples 1 with the coupling 3.

A device for connecting drill pipes is assembled as follows. Lock nipples 1, couplings 3 with connecting threads 2 are made with a step equal to not more than 1/4 of the length of its working part, for connection between themselves and threads on pipes (not shown) for connection with drill pipes, ratchet coupling halves 4 and 5, clamps 10. The ratchet half-couplings 4 and 5 are put on the connecting ends of the nipple 1 and the coupling 3 when fully screwed up and, having set them in the working position, are rigidly fixed.

The device operates as follows. With a complete screwing of the locking nipple 1 with the coupling 3, the lower end of the nipple 1 (see Fig. 1) abuts against the sealing ring 6, sealing the threaded connection, and the protrusions 7 of the upper ratchet coupling half contact the vertical planes of the troughs of the lower ratchet coupling coupling while observing the ratchet coupling half analytical expression

H = 0.8 S / Z,

where S is the thread pitch 2,

Z is the number of projections 7 of the ratchet coupling half 5 or 4.

At the same time, the ends of the locking nipple 1 and the coupling 3 come into contact, which is ensured by the constructive guaranteed gaps in their manufacture. The axial force from the drilling unit to the bottom of the well is transmitted by the contacting ends of the locking nipple 1 and coupling 3, and the torque is transmitted by thread 2 with a step equal to not more than 1/4 of the length of its working part, and ratchet half-couplings 4 and 5. Latches 10 with leaf springs 11 will provide external fastening of the device elements both during normal operation and when working with the rotation of the drill, the opposite of the worker. The contacting protrusions of the upper ratchet half-coupling with the planes of the depressions of the lower ratchet half-coupling do not allow the thread to tighten with a large step, which ensures their free and easy unscrewing when disassembling the drill.

Thus, the proposed technical solution of the device for connecting drill pipes has the following advantages over the known:

1. Provides reliable connection of drill pipes to the string.

2. Provides tight connection.

3. Excludes tightening of threaded joints even with significant torques on the downhole tool.

4. Significantly reduces the time spent on hoisting operations of the drill string by reducing the time of making-up and unscrewing pipes.

Claims (4)

1. A device for connecting drill pipes, including a device in the form of locking nipples and couplings with threads at the ends for connecting with drill pipes and with each other, characterized in that at the ends of the locking nipples and couplings interacting with each other to transmit axial force from the drilling rig to the downhole tool, two ratchet half-couplings are rigidly connected to them, the contacting surfaces of which are made in the form of protrusions and grooves congruent to them, for the perception and transmission of torque one temporarily with a threaded connection, and the height of the protrusions and depressions on each ratchet coupling half is determined from the analytical expression
H = 0.8 S / Z,
where H is the height of the protrusion or the depth of the cavity;
S is the thread pitch;
Z is the number of protrusions or depressions on each ratchet coupling half. 2. The device for connecting drill pipes according to claim 1, characterized in that the pitch of the thread connecting the locking nipple and the coupling to each other is equal to not more than 1/4 of the length of its working part. 3. The device for connecting drill pipes according to claim 1, characterized in that on the inner surface of each ratchet coupling half there are through longitudinal grooves for placement of clamps in them. 4. The device according to claim 2, characterized in that the latches are made in the form of L-shaped strips with springs, and the width of the strips is slightly less than the width of the through longitudinal grooves.

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