FR2543249A1 - METHOD AND APPARATUS FOR SEALING THE SCREWED SECTIONS OF A WELL TOOL - Google Patents

Abstract

THE INVENTION RELATES TO A METHOD AND APPARATUS FOR SEALING A SCREW JOINT BETWEEN SECTIONS 12, 14 OF A WELL TOOL 10, SUCH AS A SAFETY VALVE. EACH OF THE MALE AND FEMALE ASSEMBLIES 72, 70 HAS AN END 82, 78 ON ONE SIDE OF ITS THREAD 76, 74 AND A SHOULDER 84, 80 ON THE OTHER SIDE OF ITS THREAD. BETWEEN THE END OF THE MALE ORGAN AND THE SHOULDER OF THE FEMALE ORGAN A SEAL 86 IN SOFT METAL AND, AFTER TIGHTENING THE JOINT, AT LEAST ONE HOLE 92 IS PUNCHED THROUGH THE THE MALE BODY AND THE END OF THE FEMALE BODY IN WHICH A 94 CAP IS FORCED TO MAINTAIN LONGITUDINAL ALIGNMENT AND ROTATION ALIGNMENT OF ASSEMBLED ORGANS.

Description

Various types of oil and / or gas well tools are used in

  which the body of the tool comprises several metal sections assembled by screwing to enclose the active parts of the tool The screwed assemblies of the sections must be pressure tight. In the past, screw connections included a joint

  metallic material to seal the as-

  However, when assembling the well tool, various adjustments of the internal active organs of

  the tool must be carried out This requires that the

  screwed lessons from the well tool be over and over

  times unscrewed and re-screwed until the organs ac-

  tools are properly adjusted However the

  screwed metal assemblies with seals from ma-

  especially tend to scuff especially when the mete

  tal is a corrosion-resistant alloy When metal parts become scratched, they become defective and must be replaced, which is expensive and time-consuming Although the seals made of elastomeric material are satisfactory for initially making a tight seal under pressure they have a short lifespan in

  the unfavorable environment of temperatures and corrosive fluids

sif encountered in a well.

  The subject of the present invention is a method and an app-

  similar to assemble and seal screwed sections of a well tool by means of a metal seal providing pressure seal, in which seals can be formed and broken many times and in which the joints are held in a

  secure sealing position after final assembly.

  The present invention thus relates to a pressure-tight seal between threaded assembly members

  male and female of a well tool having a gasket

  soft metal sealing positioned between the suction members

  male and female connections which seal between the assembly members when they are screwed into each other A hole is drilled in the outside of the assembly

  formed, through the outer parts of each of the or-

  assembly glands A plug is positioned in the hole

  with a force adjustment to maintain the alignment in ro-

  tation and longitudinal alignment of the formed assembly.

  Preferably, the metal seal is carried in a recess formed in one of the assembly members and by a chamfer-formed on the other assembly member.

  may include an assembly means allowing the removal

  In addition, several holes and plugs can be formed.

  més and positioned between the assembly members The pre-

  sente invention is particularly useful in the case where the male and female threaded assembly members are in

  super-alloyed metals which tend to scuff.

  Yet another object of the present invention is to

  make a pressure-tight seal between suction elements

  male and female threaded semblance of a well tool, such

  than a safety valve The female assembly member

  has one end on one side of its thread and a shoulder-

  ment on the other side of its thread The male assembly member has one end on one side of its thread and a

  shoulder on the other side of its thread A seal

  soft metal sheath is positioned between the end of

  the male assembly member and the shoulder of the suction member

  female connection to ensure the seal between the assembly members when the assembly members are screwed into each other After forming the assembly, we

  drill a hole in the outside of the formed assembly, through

  towards the shoulder of the male assembly member and the end

  mite from the female assembly member and a plug is positioned in the hole with a force fit to maintain the rotation alignment and the longitudinal alignment of

the assembly formed.

  Other aims, characteristics and advantages of the invention

  tion will appear on reading the description which will

  follow of an embodiment of the invention currently preferred, given solely for purposes of disclosure, and on examining the appended drawings in which: FIGS -1, 2, 3 and 4 are views in elevation, in part in section, of a well safety valve using the present invention, these views following one another; and Fig 5 is a sectional view, taken along line -5 of Fig 1. The present invention will be described below, by way of example only, as incorporated in a well safety valve but it is understood that the present invention can be used with other types of well tool which

have screwed sections.

  In the drawings which will now be referred to, the general reference 10 designates a well safety valve actuated by a piston, which comprises a body or boot 12, which is composed of several sections 14, 16, 18, 20, 22

  and 24, assembled together by screwing.

  The valve 10 has a bore 26, a valve seat

  annular 28 positioned around the bore 26 and a plug

  tor 30 assembled to the body 12 by a pivot pin 32 A drain tube 34 is telescopically movable in the body

  12 and through the valve seat 28 When the drain tube

  34 is moved to a low position, the tube 34 pushes the shutter 30 away from the seat and opens the

  valve When the tube 34 is moved upwards, the shutter

  rator 30 can be applied against the seat 28 and seal the bore 26 of the valve The flow tube 34 is biased upwards by various forces such as that of a spring and the valve is closed by removing the 'application

  pressure by a hydraulic fluid transmitted by a

  control line 36 which extends to the surface of the well

  and which supplies fluid through a pipe 38 for controlling the

  flow to a chamber 40 in which it acts on one or more pistons 42 mounted mobile in the chamber 40 The pistons 42 act, in their turn, on the flow tube 34 When a sufficient hydraulic fluid pressure is applied to the pipe 36 flow control, tube

  34 is moved down to open the screen

  pet If the fluid pressure prevailing in line 36 of

  flow control is sufficiently reduced, the flow tube

  flow 34 is moved upwards beyond the seat 28 to allow the shutter 30 to close in abutment against the seat 28 The well safety valve described above is described as a whole in the patent applications of the EUA No. 383 897 filed June 1, 1982 - and NO 440 667 filed

November 10, 1982.

  The safety valve 10 comprises a threaded assembly member 50 at its top and a threaded assembly member 52 at its base to allow the safety valve to be assembled in a drill string In addition, as already indicated, the various sections 14, 16, 18, 20, 22 and 24 are joined together by screwed connections Normally, the sections, such as sections 16 and 18, are joined together by conventional cooperating threads 54 and 56 shown here as threads "Hydril" with two diameters The threaded assembly members 54 and 56 also include seals

  cooperating metal, such as the seal 58 formed on the section

  section 16 and the joint 60 formed on the section 18 Likewise, the assembly threads 50 comprise a metal joint surface 62 and the threads 52 comprise a joint surface

  metal seal 64 Similarly, other types of as-

  screwed assemblies which include metal seals from material are commonly used Metal seals from conventional material are normally satisfactory for forming screwed assemblies which do not need to be screwed and unscrewed multiple times In other words, the

  classic screw connections that include metal seals-

  specific material, such as seals 58 and 60 needed

  place the application of a high torque to ensure so

  satisfactory the watertightness of metal seals coming from my-

  In addition, if the metal seals made of material

  are subjected to repeated screwing and unscrewing, they have

  dance to scuff This is particularly the case for di-

  to corrosion-resistant alloy metals that are used today in wells When threaded fasteners are scratched, they become defective and must be replaced, which is a long and expensive operation. In general, the conventional threads 50 and 52 are satisfactory since they are simply used to mount the safety valve 10 in a train of

  rods and do not need to be screwed and unscrewed Cepen-

  other types of screw connections used in the safety valve 10, such as the screw connections between sections 14 and 16, between sections 18 and 20, between sections 20 and 22 and between sections 22 and 24 are frequently screwed and unscrewed multiple times during the assembly of the safety valve 10 In other words, during the assembly of the internal organs of the valve 10,

  the various parts must be frequently exposed and

  before the active parts are finally adjusted.

  This requires the screwing and unscrewing of the various sections.

  which increases the risk that the sections fitted with

  seals coming from material can become scratched.

  The subject of the present invention is a method and an app-

  similar to assemble threaded sections of a

  wells and ensure their tightness by means of a watertight seal

  metallic sheath which withstands the desired pressure and in

  which the assembly members can be mounted and removed

  mounted multiple times without risk of scuffing and subsequent loss of parts as they become,

this fact, defective.

  In Fig 1 which will now be referred to, there is shown a screw connection between a female assembly member 70 and a male assembly member 72 which have cooperating threads 74 and, respectively, 76 The assembly member female 70 has one end 78 on one side of its thread 74 and a shoulder 80 on the other side of its

  thread 74 The male assembly member 72 comprises an ex-

  end 82 on one side of its thread 76 and a shoulder 84 on the other side of its thread A seal 86 in

  soft metal, for example, in monel or inconel, is posi-

  clamped between the end 82 of the male assembly member 72 and the shoulder 80 of the female assembly member 70 to seal between the assembly members 70 and 72

  when the threads 74 and 76 are screwed into each other.

  The sealing member 86 has the advantage of being deformable and of producing a metal-to-metal seal, which withstands the required pressures, which is not the subject of the problems of scraping the seals from material and which does not require a joint formation torque as high as the joints

  come from matter to resist the same pressure.

  Preferably, the metal seal 86 is

  carried in a recess formed in one of the assembly members

  blage, such as a recess 88 formed at the end 82 of the or-

  male assembly gane 72, and by a chamfer formed on the other assembly member, such as a chamfer formed on the female shoulder 80 In addition, the threads 74 and 76 of the assembly members can be targeted and repeatedly unscrewed to allow adjustment of the active parts of the tool If, for any reason after the pressure test of the seal formed, it turns out that the

  metal seal 86 is defective or has become

  bare defective due to numerous assemblies and disassembly, it can be replaced easily and inexpensively compared

  replacing parts 14 and 16.

  After the tool 10 has been completed, adjusted and finally assembled, it is tested under pressure by sealing off one of its ends and applying pressure to the other end.

  to ensure that the screw connections resist pressure

  Desired Zion After the tool 10 has passed its final inspection, a hole 92 is drilled in the outside of the assembly formed, through the male shoulder 84 and the end 78 of the female assembly member 70 and a plug 94 is positioned in the hole 92, with a force fit The plug 94 maintains both the rotation alignment and the alignment

  longitudinal in the assembly formed between the file members

  tees 70 and 72 It is important to maintain the rotational alignment of the formed assembly in order to prevent any unscrewing of the threaded assembly members 74 and 76 which would have the effect that the metal seal 86 would cease to be compressed and that the assembly could start to leak In addition, it is also important to maintain the longitudinal alignment of the assembly formed In other words, in an oil well drill string in which the tool 10 can be mounted , the drill string can be subjected to various tensile and compressive loads Although the threads 74 and 76 are coupled relatively tightly, there nevertheless remains a certain degree of tolerances and if the members and 72 were moved longitudinally relative to each other at the other, the seal 86 could be subjected to

  compression forces which, while increasing the sealing-

  could deform seal 86 If seal 86 was deformed by a compression load

  and if the load was then removed, the seal-

  tee 86 could possibly retain a deformation

  manente and no longer be able to resist the pressures

quises.

  If desired, several holes 92 and plugs 94 can be used.

  read at each screw connection And although the caps 94

  generally provide a permanent link between sections

  ons screwed, a threaded assembly means 96 can be-provided in the cap to allow to tear off later more

  easily plug 94 of the hole, if necessary.

  The process of the present invention clearly results

  of the foregoing description of the apparatus and it is thus possible

  find that it aims to achieve the pressure seal of a joint between threaded assembly members of a well tool, in which the female assembly member has one end on one side of its thread and a shoulder on the other side of its thread and the male assembly member

  has one end on one side of its thread and a shoulder

  LEMENT on the other side of its thread The method includes the step which consists in assembling by screwing said male and female assembly members with a seal in

  soft metal disposed between the end of the assembly member

  male blocking and the shoulder of the female assembly member

  by applying a predetermined torque to ensure tightness-

  ity of the assembly After pressure testing of the assembly

  waterproof, the process includes the steps of

  cer a hole in the outside of the assembly formed through the shoulder of the male assembly member and through the end of the female assembly member; and insert a plug into the drilled hole with a force fit to

  maintain rotational alignment and longitudinal alignment

nal of the assembly formed

  Consequently, the invention is well suited for realizing

  serving the objectives, achieving the goals and delivering the benefits mentioned and others inherent in it

  that a mode of realization has been described for the purposes of the disclosure

  sation currently preferred, it will immediately come to es

  took many technical specialists -modified-

  which are likely to be brought to the construction and arrangement of the elements and process steps, which fall within the spirit of the invention and are covered by

the appended claims.

  Preferably the hole and the plug are round.

MVEND 1 ICATIONS

  1 A device forming a pressure-tight seal between male and female threaded assembly members (72, 70) of a

  well (10), characterized in that it comprises: a gasket

  sealing (86) of soft metal disposed between said or-

  male and female assembly ganes and ensuring sealing between the assembly members when the latter are screwed into one another; a hole (92) drilled in the outside of the formed assembly, through the outer parts of each of the assembly members and a plug (94) mounted in the hole with a force fit to keep the alignment in rotation and alignment

  longitudinal of the assembly formed.

  2 A device forming a pressure-tight seal between male and female threaded assembly members (72, 70) of a well tool, characterized in that the female assembly member (70) has one end (78 ) on one side of its thread (74) and a shoulder (80) on the other side of its thread, the male assembly member (72) has one end (82) on one side of its thread ( 76) and a shoulder (84) of

  the other side of its thread; a seal (86) -

  made of soft metal is positioned between the end of the

  male assembly and the shoulder of the assembly member

  female blocking for sealing between the assembly members when the latter are screwed into one another; a hole (92) is drilled in the exterior of the assembly formed, through the shoulder of the male assembly member and the end of the female assembly member; and a plug (94) is positioned in the hole with a force fit to maintain alignment in

  rotation and longitudinal alignment of the formed assembly.

  3 Device according to claim 2, characterized in that the metal seal (86) is carried in a recess (88) formed in one of the assembly members (72) and by a

  chamfer formed on the other assembly member (70).

  4 Device according to claim 2, characterized in that the

  plug (94) includes an assembly means (96) for

put to remove the plug -

  Device according to claim 2, characterized in that it comprises several holes (92) and several plugs (94)

  positioned between the assembly members (70, 72).

  6 Device according to claim 2, characterized in that the male and female assembly members (72, 70) are in

  superalloyed metals which tend to scuff.

  7 Device according to claim 4, characterized in that the

  hole (92) and the plug are round.

  8 Device according to claim 2, characterized in that

  the well tool is a safety valve (10).

  9 A process for making a pressure seal of a joint between male and female threaded assembly members

  (72, 70) of a well tool (10) in which the suction member

  female coupling (72) has one end (78) on one side of its thread (74) and a shoulder (80) on the other side of its thread and the male assembly member (70) has one end ( 82) on one side of its thread and a shoulder

  (84) on the other side of its thread, this process being characteristic

  terized in that it consists in assembling by screwing said

  male and female assemblies with a gasket

  ity (86) in soft metal disposed between the end of the gold-

  male assembly gane and the shoulder of the assembly member

  female latching, applying a predetermined torque to seal the assembly; drilling a hole (92) in the exterior of the formed assembly, through the shoulder of the male assembly member and through the end of the female assembly member; and introduce a plug

  (94) in the drilled hole with a force adjustment for hand-

  hold rotation alignment and longitudinal alignment

of the assembly formed.

  A method according to claim 9, characterized in that it further comprises the step which consists in testing the sealed assembly under pressure before drilling the hole

(92).

  11 Method according to claim 10, characterized in that

  that the hole (92) and the plug (94) are round.