CN210564396U - Threaded joint for high-sulfur-content high-pressure gas well gas-lift oil production pipe column - Google Patents

Abstract

The utility model provides a be used for high sulphur hydrogen sulfide, high pressure gas well gas lift oil production pipe screwed joint. The concrete structure of the coupling comprises a pipe body with two external threads and a coupling with internal threads, wherein an inner boring cylindrical surface of a pipe end is flush with a cylindrical surface of a coupling through hole, a transition arc spherical surface is arranged between the inner boring cylindrical surface and the inner diameter, and an external torque shoulder and an internal torque shoulder both adopt anti-torque shoulders of-15 degrees to-20 degrees. After the upper buckle is screwed, the end part outer torque shoulder and the end part inner torque shoulder of the pipe body, the outer conical surface sealing surface and the inner conical surface sealing surface form interference fit, a sealing barrier in a high stress area is formed, high-pressure liquid or gas can be prevented from passing through the sealing barrier, the sealing barrier can be used for a long time after being put into a well once and repeatedly operated for many times, the repeated work of putting in a pipe column before each gas lifting operation on site and taking out the pipe column after the operation is solved, high-pressure natural gas containing hydrogen sulfide can be directly injected into the pipe column, the cost of field operation of an oil field is reduced, and the sealing device has the advantages of high sealing performance, high connection strength, internal and external pressure resistance.

Description

Threaded joint for high-sulfur-content high-pressure gas well gas-lift oil production pipe column

Technical Field

The utility model belongs to the technical field of oil, natural gas exploitation, further relate to a new technology tubular column that is arranged in high pressure gas well of high sulphur hydrogen sulfide operating mode gas lift oil recovery, concretely relates to be used for high sulphur hydrogen sulfide, high pressure gas well gas lift oil production pipe column screwed joint connection structure.

Background

The natural gas well has large reservoir pressure in the early development stage, the gas reservoir pressure at the bottom of the well is very high, natural gas can be self-blown at the well mouth, and liquid at the bottom of the well, such as crude oil, formation water and the like, can be carried out from a shaft of thousands of meters while high-pressure gas is self-blown. In the later exploitation stage of the oil-gas well, because the oil gas is continuously exploited, the energy or the pressure of the stratum is continuously attenuated, the oil-gas yield, the gas-liquid ratio and the like are greatly changed, and the natural gas pressure at the bottom of the well is not enough to carry out the liquid in the shaft. The gas production of the stratum at the later stage of oil and gas exploitation is reduced, meanwhile, the production of stratum water and other liquid media is increased, the liquid accumulated liquid in the oil pipe shaft is gradually increased, when the pressure of a liquid column is higher than the pressure of the gas reservoir in a reservoir, the natural gas at the bottom of the well cannot be discharged to the upper part of the liquid column in the shaft, and no oil gas is produced at a well head. When the pressure of a liquid column in a shaft of the tubing string is greater than the pressure of a gas reservoir at the bottom of the shaft, the gas well cannot normally produce, and the original production pipe column cannot meet the capability requirement of carrying liquid, so that the liquid gas lift in the original shaft needs to be carried out.

At present, the common engineering technical method for discharging liquid in an oil gas shaft in an oil field is to put a coiled tubing with a smaller specification into an oil pipe and inject high-pressure nitrogen into the coiled tubing to perform gas lift operation. The engineering technology can solve the problem of liquid accumulation of a part of gas wells, but the main problems of the existing coiled tubing gas lift operation are as follows:

(1) because the wall thickness of the coiled tubing is very thin, the tubing string can bear a lower tensile load and cannot be run into a deeper gas well.

(2) The coiled tubing material is generally not hydrogen sulfide resistant and cannot be used in gas wells containing hydrogen sulfide or high hydrogen sulfide content environments.

(3) High-pressure nitrogen needs to be injected into the coiled tubing in site construction, the operation cost of the large-displacement nitrogen and the cost of the nitrogen are very high during site operation, and the high operation cost is difficult to bear under common well conditions, so that a plurality of low-pressure gas wells have no economic maintenance value of gas lift operation, and a plurality of oil and gas well resource development wastes are caused.

(4) The coiled tubing needs to be lifted out after the operation is finished every time, and the coiled tubing does not have the advantage of repeated operation at intervals for multiple rounds.

(5) The well mouth of the coiled tubing is difficult to suspend and construct, and the operation risk is higher.

The sleeve threaded joint structure is mentioned in the patent document with the patent number of 'CN 202544761U', and comprises two pipe bodies 1 and a coupling 2, wherein an external thread is arranged on the pipe body 1, an internal thread is arranged on the coupling 2, a long nose end is designed at the end part of the external thread on the pipe body 1, a circle between an inner main anti-torque shoulder surface and a sealing surface is in arc surface transition, an outer conical surface sealing surface and an inner conical surface sealing surface form metal interference fit, the outer main anti-torque shoulder surface and the inner main anti-torque shoulder surface form metal interference fit, and the end surfaces of the two pipe bodies 1 form interference butt fit in the center of the coupling 2. But this structure can not be used for the tubular column threaded connection of high sulfur content, high pressure gas well gas lift oil recovery operation operating mode, its main weak point that exists:

(1) the pipe body structure in the patent is applicable to a casing pipe with a specification of more than 41/2 in (114.3mm), cannot be used for the size of an oil pipe with a small specification, and meanwhile, the connection strength of a threaded joint is only 70-80% of that of the pipe body, so that the requirement on the tensile strength of a gas-lift oil production pipe column cannot be met;

(2) in the structure, a right-angle transition part of a cylindrical surface and a shoulder surface of the tool withdrawal groove has large stress concentration, and a high stress concentration area of the coupling is very easy to break in a hydrogen sulfide sensitive environment.

(3) Because the inner hole and the center of the pipe have the non-concentricity phenomenon in the hot rolling perforation forming process of the steel pipe, the sealing surface part of the pipe body has the non-uniform wall thickness eccentricity phenomenon in the circumferential direction, the stress distribution of the sealing part is non-uniform, and the sealing reliability is reduced.

(4) When the tubular column receives dead weight or great tensile load, the external thread joint shoulder surface of back butt joint can separate certain clearance after the thread joint is buckled, consequently takes place the crevice corrosion easily and sealing performance greatly reduced.

Disclosure of Invention

The utility model provides a novel high hydrogen sulfide of containing, new technology tubular column of gas lift oil recovery in the oil gas well of high-pressure gas well condition to overcome the low problem that easily breaks or slippage inefficacy phenomenon and sealing reliability are low that takes place of unconventional small format oil pipe tensile strength that prior art exists.

In order to achieve the above purpose, the utility model provides a technical scheme is: a threaded joint connecting structure for a high-sulfur-content high-pressure gas well gas lift oil production pipe column comprises two pipe bodies with external threads and a coupling with internal threads, wherein the external threads of the two pipe bodies and the end part of an outer sealing surface pipe are correspondingly matched with the internal threads and a sealing surface of the coupling and are screwed, screwed and fastened; the method is characterized in that: an outer torque shoulder is arranged at the end part of the pipe body, an outer transition cylindrical surface and an outer sealing surface are arranged between the outer thread of the pipe body and the outer torque shoulder, an inner boring cylindrical surface of the end of the pipe body is flush with a cylindrical surface of a coupling through hole, and a transition arc spherical surface is arranged between the inner boring cylindrical surface and the inner diameter of the pipe body; the external torque shoulder and the internal torque shoulder both adopt anti-torque shoulders with the angle of minus 15 degrees to minus 20 degrees.

The outer sealing surface and the inner sealing surface are both metal conical surface-conical surface sealing surfaces, the diameter taper is 1: 4-1: 5, and the radial interference magnitude is 0.15-0.60 mm.

External screw thread and internal thread all adopt the buttress thread of positive angle loading face, 8 threads on every 25.4mm length, and pitch is 3.175mm, and the screw thread tapering is 1:16, the thread crest is parallel to the taper generatrix; the bearing surface angle of the thread is selected from +1 degree to +3 degrees, the guide surface angle is selected from +10 degrees to +12 degrees, the tooth height of the external thread is 0.8 +/-0.05 mm, the tooth height of the internal thread of the coupling 2 is 0.9 +/-0.05 mm, and the interference magnitude after the thread is buckled is selected from 0.1mm to 0.15 mm.

The utility model has the advantages of it is following:

1) the utility model adopts the outer diameter design of the small coupling with equal tensile strength of the screwed joint and the pipe body, the outer diameter of the coupling is smaller, but the tensile efficiency of the screwed joint is 100 percent; the problem of the difficult problem of putting in a connecting hoop type tubular column in a smaller shaft inner diameter of an on-site tubing string is solved, and the tensile property of the tubular column is improved by more than 35 percent compared with that of a tubular column of a direct connection type threaded joint.

2) The utility model provides a pair of radial metal gas seal structure can realize injecting into the high-pressure natural gas that contains hydrogen sulfide at the scene and carry out the gas lift oil recovery operation, has higher tensile/compression, sealing performance, improves tubular column screwed joint's joint strength, and screwed joint's joint strength, anti interior pressure, external pressure intensity and body wait strongly have improved the seal reliability and the security when the operation.

3) The thread joint has good anti-thread gluing performance, and the tooth tops and tooth sides of the threads after the external threads and the internal threads are buckled have small gaps, so that the thread gluing phenomenon can be prevented after the threads are buckled/unbuckled for many times on site, and the service life is prolonged.

4) The novel pipe column can be hung at the well head for a long time after being put into the well once, gas lift operation is carried out at the well head for a plurality of times according to the yield of an oil gas well, the high-sulfur-content natural gas is directly injected back into the stratum after being compressed, the repeated work of pulling out the pipe column after the pipe column is put into the well and the operation before the gas lift operation is carried out on site is conveniently and quickly solved, the efficiency is improved, and the cost is reduced.

5) The inner bore hole cylindrical surface of the external thread pipe end sealing surface part and the inner diameter of the pipe body are in transition by adopting a larger arc surface, so that the stress is reduced; meanwhile, the wall thickness of the sealing surface after the inner boring is more uniform, so that the stress distribution after the threaded connector is buckled up is more uniform, the sealing reliability is higher, and the requirement on high-pressure sealing performance under severe corrosion working conditions is met.

6) The natural gas containing high content of hydrogen sulfide is directly lifted and compressed by the oil-gas well site and then is subjected to gas lift operation production, so that the waste of operation gas media and subsequent gas separation treatment (such as nitrogen) are avoided, the operation gas cost is reduced, the production cost of an oil field is reduced, and the benefit is increased.

Drawings

FIG. 1 is a structural diagram of the threaded connection of the airtight gas lift oil extraction speed pipe of the present invention;

FIG. 2 is a view showing the structure of a pipe body;

FIG. 3 is a diagram of a collar structure;

FIG. 4 is a partial schematic view of an externally threaded pipe end;

FIG. 5 is a schematic view of a portion of a coupling tube end;

in the figure, 1-tube, 2-coupling, 3-external thread, 4-external transition cylindrical surface, 5-external conical surface sealing surface, 6-external torque shoulder, 7-internal boring cylindrical surface, 8-internal boring transition cylindrical surface, and 9-tube internal diameter; 10-internal thread, 11-internal thread transition cylindrical surface, 12-internal conical surface sealing surface, 13-internal torque shoulder and 14-internal through hole cylindrical surface.

Detailed Description

The present invention will be described in detail with reference to the following embodiments.

The utility model relates to a be used for high sulphur hydrogen sulfide, high pressure gas well gas lift oil production pipe screwed joint connection structure, including having two body 1 and a coupling 2 that has the internal thread, the corresponding cooperation and the screwing of internal thread 10 and sealed face 11 of the external screw thread 3 of two body 1 and the 5 pipe ends of external seal face and coupling 2 are screwed and are connected the fastening, 2 both ends of coupling are provided with two sections internal threads 10 of symmetry, are provided with convex through-hole cylinder 14 between the internal thread 10, are internal thread transition 11 cylinder, interior sealed face 12 and interior moment of torsion circular bead 13 between internal thread 10 and the through-hole cylinder 14 in proper order; an outer torque shoulder 6 is arranged at the end of the pipe body 1, an outer transition cylindrical surface 4 and an outer sealing surface 5 are arranged between the outer thread 3 of the pipe body 1 and the outer torque shoulder 6, an inner boring cylindrical surface 7 at the end of the pipe body 1 is flush with a through hole cylindrical surface 14 of the coupling 2, and a transition circular arc spherical surface 8 is arranged between the inner boring cylindrical surface 7 and the inner diameter 9.

The external thread 3 and the internal thread 10 are in interference fit after being buckled and screwed, a fit clearance is arranged between the external transition cylindrical surface 4 and the internal thread transition cylindrical surface 11, the external conical surface sealing surface 5 and the internal conical surface sealing surface 12 are in interference fit, and the external torque shoulder 6 and the internal torque shoulder 13 are matched to form 2 metal-metal interference fit areas.

The external thread 3 and the external sealing surface 5 of the two pipe bodies 1 are correspondingly matched with the internal thread 7 and the internal conical surface sealing surface 12 of the coupling 2 and are screwed and screwed tightly. After the pipe body is screwed on, the outer torque shoulder 6 at the end part of the pipe body 1 is in interference fit with the inner torque shoulder 10, the outer conical surface sealing surface 5 and the inner conical surface sealing surface 12 to form a metal-metal sealing barrier in a high stress area, and high-pressure liquid or gas can be blocked from passing through.

The threaded connection part of the pipe body 1 is sequentially composed of an external thread 3, a transition cylindrical surface 4, an external conical surface sealing surface 5, an external torque shoulder 6, an internal boring cylindrical surface 7, an internal boring transition spherical surface 8 and the like. The coupling 2 is symmetrically provided with internal threads 10 at two ends, and sequentially comprises the internal threads 10, a transition cylindrical surface 11, an inner conical surface sealing surface 12, an inner torque shoulder 13, an inner through hole cylindrical surface 14 and the like. The outer torque shoulder 6 of the pipe body 1 and the inner torque shoulder 13 of the coupling 2 are negative-angle torque shoulders, so that the inward deformation capacity of the pipe body threads can be effectively restrained, and the external pressure and crushing strength of the threaded joint is improved.

The tooth height of the external thread 3 of the pipe body 1 is 0.8 +/-0.05 mm, the tooth height of the internal thread 10 of the coupling 2 is 0.9 +/-0.05 mm, the thread pitches are 3.175mm, the taper diameter is 1:16, the bearing surface angle of the thread is between +1 and +3 degrees, the guide surface angle is between +10 and +12 degrees, and the interference of the thread is selected from 0.1 to 0.15 mm. The outer conical surface sealing surface 5 of the pipe body 1 and the inner conical surface sealing surface 12 of the coupling 2 are of metal-metal sealing surface structures, the diameter taper is 1: 4-1: 5, the radial interference magnitude is 0.15-0.60 mm, the shoulder angle of the outer torque shoulder 6 and the inner torque shoulder 13 is-15 degrees-22 degrees, transition arcs are arranged between the coupling 2 and each connecting section on the pipe body 1, and stress concentration is reduced.

The external thread 3 and the internal thread 10 both adopt modified buttress threads with positive angle bearing surfaces, and each 25.4mm of length is provided with 8 threads.

The upper buckle screwing operation process:

the external thread of the pipe body 1 and the internal thread of the coupling 2 are manually pulled and meshed, then are buckled up to a manual tightening position, and then are tightened and screwed by using hydraulic tongs, so that the external thread 3 and the internal thread 10 of the pipe body 1 form interference fit firstly, the external conical surface sealing surface 5 and the internal conical surface sealing surface 12 of the coupling 2 form interference fit after the screwing up is further rotated, and finally the external torque shoulder 7 and the internal torque shoulder 13 form interference fit and the screwing up is stopped; in the screwing process of the screwed joint, the torque in the thread interference fit stage is slowly increased firstly, the torque is increased quickly after the sealing surface is contacted, the torque is sharply screwed up after the interference fit of the torque shoulder surface, and screwing up is stopped when the total screwing-up torque reaches the preset torque. After the screwed joint is screwed, the external thread pipe body 1 and the internal thread coupling 2 form an external conical surface sealing surface 5 and an internal conical surface sealing surface 12 in interference fit, and two metal-metal high-stress interference fit areas of the external torque shoulder 6 and the internal torque shoulder 13 improve the reliability of air tightness. A fit clearance is arranged between the internal thread tool retracting cylindrical surface 11 of the coupling 2 and the external transition cylindrical surface 5 of the pipe body 1, high-pressure thread grease extruded in the screwing-up process can be stored, and the influence of the thread grease on the sealing performance is reduced.

The utility model discloses a gas lift oil recovery speed tubular column hangs and the well head cross at the supporting dedicated well head of well head, and the part adopts special anti hydrogen sulfide's airtight structure speed tubular column and gas lift valve in the pit, and the gas lift operation adopts special well head preventer and anti-blowout system such as back pressure valve, for going into, operation and play out provide the safety guarantee under the tubular column. The material of the gas lift oil recovery speed tubular column of new design has anti hydrogen sulfide, and threaded joint has better air tightness, can inject the well into after the direct compression of the natural gas of high sulfur hydrogen sulfide, greatly reduced the compressed gas cost in the construction to the natural gas of gas lift operation in the well into can be retrieved. The matched wellhead suspension and wellhead four-way design ensures that the gas lift oil extraction speed pipe column can suspend the wellhead for a long time, and when the yield of accumulated liquid in the oil pipe shaft is high and the gas yield is low, the gas lift operation can be performed on the liquid in the oil pipe shaft through the control of the wellhead four-way valve, so that the production operation efficiency is greatly improved. After the gas lift is finished, the velocity string can also be produced, so that the production channel of the oil string is increased, and the yield of oil gas is improved. The gas lift oil extraction velocity tubular column can improve the liquid carrying flow velocity of the high-sulfur hydrogen sulfide well, improve the liquid loading condition, recover the self-spraying or realize the clearance self-spraying production, and reduce the oil extraction cost.

According to the field operation operating mode and the corrosive environment requirement of gas lift oil recovery, the utility model provides a gas lift oil recovery speed tubular column is the phi 42.16 x 6.5mm 80 steel level anti hydrogen sulfide tubular column of non-API SPEC 5CT standard, and screwed joint is the airtight sealing head of coupling formula. The utility model relates to an airtight seal threaded connection structure for gas lift operation of a high-sulfur-containing gas well, which solves the difficulty that the sealing reliability of a high-pressure natural gas threaded joint directly injected with high-sulfur hydrogen sulfide in field operation is not high, has the advantages that a speed pipe column can be used for a long time after being put into a well and repeatedly operated, and greatly reduces the cost of field operation of the oil field; the natural gas with high hydrogen sulfide content in the well or the adjacent well can be compressed and injected into the gas well, so that the waste of compressed gas is avoided, and the cost of the working gas is greatly reduced.

The content of the present invention is not limited to the examples, and any equivalent transformation adopted by the technical solution of the present invention is covered by the claims of the present invention by those skilled in the art through reading the present invention.

Claims (3)

1. A threaded joint for a high-sulfur-content high-pressure gas well gas lift oil production pipe column comprises two pipe bodies (1) with external threads and a coupling (2) with internal threads, wherein the pipe ends of external threads (3) and an external sealing surface (5) of the two pipe bodies (1) are correspondingly matched with the internal threads (10) and the sealing surface of the coupling (2) and are screwed, screwed and fastened, two sections of symmetrical internal threads (10) are arranged at two ends of the coupling (2), a convex through hole cylindrical surface (14) is arranged between the internal threads (10), and an internal thread transition cylindrical surface (11), an internal sealing surface (12) and an internal torque circular bead (13) are sequentially arranged between the internal threads (10) and the through hole cylindrical surface (14); the method is characterized in that: an outer torque shoulder (6) is arranged at the end part of the pipe body (1), an outer transition cylindrical surface (4) and an outer sealing surface (5) are arranged between the outer thread (3) of the pipe body (1) and the outer torque shoulder (6), an inner boring cylindrical surface (7) at the end head of the pipe body (1) is flush with a through hole cylindrical surface (14) of the coupling (2), and a transition arc spherical surface (8) is arranged between the inner boring cylindrical surface (7) and the inner diameter (9) of the pipe body; the external torque shoulder (6) and the internal torque shoulder (13) both adopt anti-torque shoulders with the angle of minus 15 degrees to minus 20 degrees.

2. The threaded joint for the high-sulfur high-pressure gas well gas lift production tubing string as recited in claim 1, wherein:

the outer sealing surface (5) and the inner sealing surface (12) are both metal conical surface-conical surface sealing surfaces, the diameter taper is 1: 4-1: 5, and the radial interference magnitude is 0.15-0.60 mm.

3. The threaded joint for the high-sulfur-content high-pressure gas well gas lift production tubing string as claimed in claim 1 or 2, wherein:

external screw thread (3) and internal thread (10) all adopt the buttress type screw thread of positive angle loading face, 8 threads on every 25.4mm length, and pitch is 3.175mm, and the screw thread tapering is 1:16, the thread crest is parallel to the taper generatrix; the bearing surface angle of the thread is selected from +1 degree to +3 degrees, the guide surface angle is selected from +10 degrees to +12 degrees, the tooth height of the external thread is 0.8 +/-0.05 mm, the tooth height of the internal thread of the coupling (2) is 0.9 +/-0.05 mm, and the interference after the thread is buckled is selected from 0.1mm to 0.15 mm.

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