CN205330561U - Highly resistance moment of torsion oil casing thread connection structure - Google Patents

Abstract

The utility model provides a highly resistance moment of torsion oil casing thread connection structure, includes steel pipe and coupling, is provided with the external screw thread at the linkage segment of steel pipe, all is provided with the internal thread at the inner wall both ends of coupling, is provided with the moment of torsion circular bead at the inner wall mid portion of coupling, the internal diameter less than or equal to steel bore of pipe of moment of torsion circular bead, the internal thread of coupling is provided with the step escape with the junction of moment of torsion circular bead, and coupling internal screw thread head and the tail both ends are equipped with conical sealing surface, are provided with the guide angle on two inner wall of the port of coupling, and the top of body is equipped with the chamfer, and steel pipe and coupling mesh through external screw thread and internal thread and buckle, the conical sealing surface and the steel pipe external screw thread contact segment interference fit of coupling, and the top terminal surface of steel pipe is closely laminated with the side of moment of torsion circular bead. The utility model provides the high anti torsional performance of screw is avoided the screw to twist excessively and is led to the fact the screw damage, has improved the sealing performance of oil pipe post, has increased the life of oil pipe post.

Description

A kind of high torque resistant oil casing threaded connection structure

Technical field:

This utility model relates to petroleum gas oil bushing threaded connector, specifically a kind of high torque resistant oil casing threaded connection structure。

Background technology:

Along with the enlarging of the technological transformation of domestic tubing and casing enterprise and plant area, tubing and casing obtains development at full speed at home, and the prescription of tubing and casing is also more and more higher。Tubing and casing is the vitals that oil and natural gas produces, and its consumption is very huge, has accounted for about the 50% of petroleum industry steel total amount at present。The tubing and casing course of processing includes: latus rectum, car silk, coupling pre-screwing, box cupling twist-on, hydraulic pressure test, is coated with wet goods operation, and wherein, box cupling twist-on operation is a very important Quality Control Links。Nipple position is link the weakest during whole tubing and casing couples, and the failure accidents more than 80% betides this, causes huge economic loss。Affecting a lot of because have of tubing and casing quality of connection, torque wrench moment is exactly one of them。Torque wrench moment is too small, and body screw thread and box cupling screw thread can not be combined closely, and is in use susceptible to leakage and slips；Torque wrench moment is excessive, the Problem of Failure such as easily make again tubing and casing generation thread gluing, tear。At present, the quality control requirement of box cupling twist-on operation performs by the API5C1 standard of American Petroleum Institute, so that whether the moment of torsion of twist-on reaches requirement moment of torsion as criterion, judged by the externally threaded twist-on degree of depth J value of tubing and casing body, twist-on degree of depth J value has the tolerance range requirement of a relative loose, for 12.7mm。

Carry out in the operating process of twist-on at Oil Field at present, due to the restriction by each oil field twist-on capacity of equipment and operation employee's level of skill, screw thread does not often have the foundation that moment of torsion quantifies in the process of twist-on, but only judge whether twist-on puts in place with the experience of operator and perusal, very easily cause screw thread excessively to twist and cause that screw thread damage or screw thread twist-on tightness are not in place, the dimensional fits adding internal and external threads is different, and different twist-on thread compounds, J value excursion after box cupling twist-on is also relatively big, and error is between 10mm。Additionally, conventional API tubing product is after the twist-on pipe of box cupling two, one section of neutral gear gap can be left in the middle of box cupling, fluid in body can be caused vortex phenomenon by this gap in the process of oil well oil-pumping, one fluid pressure can produce loss, two carry out eddy current can produce to wash away operation to box cupling neutral gap, affects the service life of tubing string。

Utility model content:

The purpose of this utility model is to provide a kind of high torque resistant oil casing threaded connection structure, existing screw connection structure adds moment of torsion step, make it can fix screw thread twist-on degree of depth J value in the process of upper button, the moment of torsion that simultaneously original thread bears becomes moment of torsion that screw thread bears and moment of torsion two parts that moment of torsion step bears, improve the torque resistant performance of screw thread, avoiding screw thread excessively to twist causes screw thread to damage, eliminate the neutral gap in the middle of former API tubing coupling, improve the sealing property of tubing string, avoid fluid simultaneously and produce, at tubing string, the phenomenon that box cupling is washed away by eddy current, decrease the fluid pressure extent of damage in tubing string, improve the service life of tubing string。

The technical scheme that this utility model is taked is as follows:

A kind of high torque resistant oil casing threaded connection structure, including steel pipe and box cupling, linkage section at steel pipe is provided with the inclined laddertron extracorporeal thread of taper, screw thread in the inclined laddertron body of the taper that the inwall two ends of box cupling are provided with the external screw thread of two steel pipes docked mutually matches, it is characterized in that: the inwall mid portion at box cupling is provided with torque shoulder, the width of torque shoulder and twist-on deep equality, the internal diameter of torque shoulder is less than or equal to the internal diameter of steel pipe, the female thread of described box cupling and the junction of torque shoulder are provided with step escape, the head and the tail two ends of coupling inner thread are provided with conical seal (contact) face, the two-port inwall of box cupling is provided with guide angle, it is provided with chamfering on the top of steel pipe, steel pipe and box cupling are engaged upper button by external screw thread and female thread, the conical seal (contact) face of box cupling and steel pipe external screw thread contact portion interference fit, the top end face of steel pipe and the side of torque shoulder fit tightly。

Further, the internal diameter of described torque shoulder is equal to the internal diameter of steel pipe。

Owing to adding torque shoulder on existing box cupling, make it can fix screw thread twist-on degree of depth J value in the process of upper button, simultaneously moment of torsion is individually born by original thread and is separated into screw thread and torque shoulder two parts bear jointly, improve the torque resistant performance of screw thread, avoiding screw thread excessively to twist causes screw thread to damage, and oil pipe is not susceptible to the phenomenon of screw thread damage when Reusability。Torque shoulder eliminates the neutral gap in the middle of former API tubing coupling simultaneously, make to seamlessly transit between body and body, improve the sealing property of tubing string, the protrusion height of torque shoulder is be more than or equal to the thickness of steel pipe tube wall, thus avoid fluid in oil pumping process and produce, at tubing string, the phenomenon that box cupling is washed away by eddy current, decrease the fluid pressure extent of damage in tubing string, improve the service life of tubing string。The junction of coupling inner thread Yu torque shoulder is provided with step escape, and thread compound unnecessary in steel pipe with the process of the twist-on of box cupling can be extruded in step escape。The two-port inwall of box cupling is provided with guide angle, the top of steel pipe is provided with chamfering, it is easy to the self-centering centering twist-on of fastener for connection thread segment and box cupling, prevent screw thread from the defect of uneven wear occurring in twist-on process, contrasting with prior art twist-on, the moment of torsion that this threaded form can be born is 1.5～1.8 times of API tubing round thread type of attachment。

Accompanying drawing illustrates:

Fig. 1 is structural representation of the present utility model；

Fig. 2 is the structural representation of box cupling；

In figure: 1-steel pipe；2-box cupling；11-external screw thread；12-chamfering；21-female thread；22-torque shoulder；23-step escape；24-conical seal (contact) face；25-guide angle。

Detailed description of the invention:

Below in conjunction with accompanying drawing, the technical solution of the utility model is clearly and completely described。

A kind of high torque resistant oil casing threaded connection structure, as shown in Fig. 1～Fig. 2, including steel pipe 1 and box cupling 2, linkage section at steel pipe 1 is provided with the inclined laddertron extracorporeal thread 11 of taper, screw thread 21 in the inclined laddertron body of the taper that the inwall two ends of box cupling 2 are provided with the external screw thread 11 of two steel pipes 1 docked mutually matches, inwall mid portion at box cupling 2 is provided with torque shoulder 22, the width of torque shoulder 22 and twist-on deep equality, the internal diameter of torque shoulder 22 is equal to the internal diameter of steel pipe 1, the female thread 21 of described box cupling 2 is provided with step escape 23 with the junction of torque shoulder 22, the head and the tail two ends of box cupling 2 female thread 21 are provided with conical seal (contact) face 24, the two-port inwall of box cupling 2 is provided with guide angle 25, it is provided with chamfering 12 on the top of steel pipe 1, steel pipe 1 and box cupling 2 are engaged buckleing by external screw thread 11 and female thread 21, conical seal (contact) face 24 and the steel pipe 1 external screw thread 11 contact portion interference fit of box cupling 2, the top end face of steel pipe 1 and the side of torque shoulder 22 fit tightly。

Before dispatching from the factory, one side of box cupling 2 first puts in place with the linkage section twist-on of a steel pipe 1, and transport is to oil field, it is necessary to carries out twist-on with another root steel pipe again when going into the well and goes into the well, forms airtight casing string。Snapping through in twist-on in journey, steel pipe 1 and box cupling 2 are screwed, and the external screw thread 11 on steel pipe 1 and the female thread 21 on box cupling 2 screw and be combined together until starting interference, produce certain contact stress。When top end face and when only torque shoulder 22 contacts of box cupling 2 of steel pipe 1, it is automatically stopped when screwing the torque value of moment of torsion rapid increase immediately arrival design and screws, for providing twist-on location accurately between steel pipe 1 and box cupling 2。Now steel pipe 1 and box cupling 2 can guarantee that bonding strength meets or exceeds body intensity, will not first leak with body when being subject to intrinsic pressure or external pressure。Then transfer tubing string proceed next root steel pipe 1 on link and connect。

High torque resistant oil casing threaded connection structure embodiment described in the utility model is not limited to upper example, also has the function replacing structures such as a lot, as long as adopting all technical schemes of technical thought of the present utility model all to belong to protection domain of the present utility model。

Claims (2)

1. one kind high torque resistant oil casing threaded connection structure, including steel pipe (1) and box cupling (2), linkage section at steel pipe (1) is provided with the inclined laddertron extracorporeal thread (11) of taper, it is provided with screw thread (21) in the inclined laddertron body of taper that the external screw thread (11) with two steel pipes (1) docked mutually matches at the inwall two ends of box cupling (2), it is characterized in that: the inwall mid portion at box cupling (2) is provided with torque shoulder (22), the width of torque shoulder (22) and twist-on deep equality, the internal diameter of torque shoulder (22) is less than or equal to the internal diameter of steel pipe (1), the female thread (21) of described box cupling (2) and the junction of torque shoulder (22) are provided with step escape (23), the head and the tail two ends of box cupling (2) female thread (21) are provided with conical seal (contact) face (24), the two-port inwall of box cupling (2) is provided with guide angle (25), it is provided with chamfering (12) on the top of steel pipe (1), steel pipe (1) and box cupling (2) are engaged upper button by external screw thread (11) and female thread (21), the conical seal (contact) face (24) of box cupling (2) and steel pipe (1) external screw thread (11) contact portion interference fit, the side of the top end face of steel pipe (1) and torque shoulder (22) fits tightly。

2. high torque resistant oil casing threaded connection structure according to claim 1, is characterized in that: the internal diameter of described torque shoulder (22) is equal to the internal diameter of steel pipe (1)。