FR2530285A1 - REPECHAGE SLIDER ACCELERATOR - Google Patents

Abstract

THE INVENTION RELATES TO A REDUCING OR DRILLING SLIDE ACCELERATOR. THE ACCELERATOR INCLUDES A TOOL BODY 12 OF ELONGATED TUBULAR SHAPE, PROVIDED WITH A SHOULDER 17 DIRECTED INWARDS AND A CHUCK 13 OF ELONGATED SHAPE, MOUNTED TO SLIDE AXIALLY IN THIS TOOL BODY AND INCLUDING A SHOULDER 18 DIRECTED OUTSIDE, SEVERAL SPRINGS 29 IN THE FORM OF TRUNCONIC DISCS ARE PROVIDED INSIDE THE TOOL BODY, AROUND THE CHUCK AND BETWEEN THE SHOULDERS 17, 18. APPLICATION IN THE FIELD OF DRILLING OIL WELLS.

Description

REPECHAGE SLIDER ACCELERATOR

  The present invention relates, in general, to

  fishing reels used in a borehole to clear stuck objects.

  More specifically, the present invention relates to an accelerator usable with a retrieval slide having a working stroke between a setting position and an impact position, as well as

  a slide latch reacting to a force and holding the slide

  in the adjustment position until a preselected

applied to it.

  During the drilling and termination of deep wells such as petroleum extraction wells, objects such as a drill pipe, casing, well tools and other equipment are sometimes stuck in the well and do not can not be removed by applying ordinary force directed upwards. In such conditions, it is necessary to exert on the stuck object large forces of release to release it for its extraction from the well. devices to produce such clearing forces and they are

called "retrieving slide".

  Retrieving slides generally comprise a body which is attached to the jammed object and a mandrel slidably mounted in the body and which is connected to the surface via a hose or cable The body carries an anvil and the mandrel a hammer Means are provided to connect, separably, the mandrel to

  body to hold the anvil and the hammer in a space condition-

  This spacing distance is called the stroke of the slide.

  The separable connecting means are arranged to be separated when the tension exerted on the slide exceeds a certain level. When the connecting means separate, the hammer can move freely.

  up to hit the anvil.

  In order for the mandrel to move upwards upon release of the connecting means, a rebound energy must be stored

  in the tube train or cable disposed between the surface and the mandrel.

  Typically, the stored rebound energy is distributed throughout the system and includes elongation in the pipe, extension of the hoist cable, and some compression of the derrick.

  There are several limitations to the backstage efficiency of

  For example, in deflected or curved holes, the friction of the

  pipe against the wall of the hole reduces the speed at which the energy

  length of storage is transferred to the slide during the release

  ration of the connecting means, which reduces the clearance forces.

  Also at shallow depths there is only a small

  hose or cable in which the rebound energy can be stored As a result, for shallow depths, efficiency

  rehearsal slides are limited.

  In an attempt to improve the efficiency of the retrieval slides, a number of known devices have been developed.

  which are called accelerators, backstage auxiliaries

  ge or intensifiers The main function of these devices is

  to store the rebound energy in the device, which is in-

  seated in the casing immediately above the retrieving slides and drill connections or overload bars, instead of being introduced into the pipe or cable A device of this type is manufactured by the company "Bowen Tools Inc." and is shown generally in the 1976-77 "Composite Catalog" on page 734, and in more detail in Bowen Tools Inc. Technical Manual No. 4019 The Bowen Accelerator stores energy by compression Another device of this type is manufactured by the company "Johnston" and is generally represented in the "Composite Catalog" of 1976-1977.

  at page 3625 Johnston burns energy by compres-

gas.

  The Johnston and Bowen devices have a number of

  If a seal becomes defective, the device

  In addition, both devices can

  High pressures during operation and they are subject to mechanical breakdowns when operating on the surface or in the vicinity of it. In addition, because of the gas or fluid load of the known devices, the elastic force exerted on the retrieving slide increases with temperature As a result, when the temperature conditions

253 C 285

  in the well change, the force generated by the device also varies

  is lying. The object of the invention is therefore to overcome the disadvantages

known achievements.

  Briefly, the aforementioned and other objects are achieved with the retrieval slide accelerator according to the invention, which comprises a tubular tool body and an elongate mandrel axially slidably mounted in the housing. tool body The tool body comprises

  an internal shoulder and the mandrel has a shoulder-directed towards the ex-

  inside and which defines with the other shoulder a chamber with internal springs

  between the mandrel and the body Several springs in the form of longitudinal discs

  conical are stacked around the mandrel in said chamber Means are provided to maintain the pressure in the chamber substantially at the same level as the pressure prevailing outside the tool body during the

  step of the retrieving slide accelerator.

  The disk-shaped springs are selected so as to have a composite elasticity constant such as compression of the springs over a length greater than the stroke of the retrieval slide with which the accelerator according to the invention is used, generates a force less than the force required to release the linkage means of the slide In other words, the disk-shaped springs are chosen so that, during the course of the accelerator, they extend from a distance greater than the stroke of the slide, so that practically all the movement produced during the race of the retrieving slide

is generated by the accelerator.

  According to one aspect of the invention, the set of shaped springs

  of discs comprises a first series having a length of compres-

  at least equal to the race of the repechage and a constant

  of total elasticity such as the force generated over the length of com-

  pressure is equal to the force required to clear the slides, and a second set of springs having a composite spring constant

  greater than that of the first series.

  Other advantages and features of the invention will be

  obvious in the rest of the description, given by way of non-limiting example.

  2, in which: FIG. 1 is a diagrammatic view of the accelerator according to the invention, in combination with drill connections and a slide;

  immediately before the release of the mechan-

  me slide lock; Figure 2 is a schematic view, similar to Figure 1, showing the slide after release of the lock but before the impact; Figure 3 is a schematic view, similar to Figures 1 and 2, showing the slider in the impact position;

  FIG. 4a is a sectional view of the upper end of the access

  slide editor according to the present invention;

  FIG. 4b is a sectional view of the lower end of the access

  slide editor according to the invention.

  Referring now to the drawings, and first of all to the figures

  1 to 3, it can be seen that the retrieval slide accelerator according to the invention

  The accelerator 11 comprises a tubular tool body 12 and a tubular mandrel 13 axially slidably mounted in the tool body 12. The mandrel 13 has at its upper end a tool coupling 14 which is arranged

  to be connected to a drill pipe or other tool support means.

  The lower end of the tool body 12 is profiled so as to define

  a tool coupling 15 which is arranged to be connected to means of

  for example, drill connections 16 or overload bars.

  The retrieving slide accelerator It is designed to be used with a repechage slide, designated as a whole by the

  numerical reference 20 and with a limited rise stroke.

  Chage 20 is preferably a mechanical slide of the type described in US Pat. No. 4,333,542; however, the accelerator 11 may be used with other limited rise travel slides, including hydraulic slides.

  The slide 20 comprises an elongate body 21 and an action mandrel

  The slide body 21 is arranged to form an internal anvil 23, while the actuating mandrel 22 is shaped to define a hammer 24. The slide 20 comprises a lock 25.

  which establishes a separable connection between the body 21 and the action mandrel

  When the slide body 21 and the actuating mandrel 22 are locked together, the anvil 23 and the hammer 24 are spaced apart by a distance S as shown in FIG.

  is called the stroke of the retrieval slide The lock 25 is triggered

  chable when the axial tension exerted entered the slide body 21 and

  the actuating mandrel 22 exceeds a certain level.

  The actuating mandrel 22 of the slide 20 has at its upper end a tool connector 27 which is arranged to be connected to drill collars. The slide body 21 has, at its lower end, a tool coupling 28 which is arranged to be connected to a retrieval tool, if the slide-20 is used as a retrieval slide, or with drill collars if the slide 20 is intended for

  be used as a drill string.

  The tool body of the slide accelerator It is shaped so as to define an internal shoulder 17 and the accelerator mandrel 13 is profiled so as to define a shoulder 18 The shoulders 17 and 18 cooperate to delimit a spring chamber 19 which contains a stack

  of springs 29 in the form of frustoconical discs The springs 29 are

  move the shoulders 17 and 18 away from each other.

  In Figure 1, the slider 20 is shown immediately before the release of the latch 25 The spring assembly 26 of the slider 20 is compressed to produce a force slightly less than the force

  The disc-shaped springs 29 of the accelerator

  The compression of the springs 29 causes them to store energy which, when the latch 25 is released, is applied to the drill collars 16 and to the sprocket. The springs 29 are selected and arranged to have a composite elasticity constant such that

  the extension of the slide accelerator 11 during charging is su

  below the S run of the slide 20.

  Looking more particularly at Figure 2, we see that the

  slide 20 is shown at the instant succeeding the release of the

  When the latch 25 is released, the slider 21 and the-man-

  22 can move axially freely one by

  relationship to the other, so that the hammer 24 can get closer to the

  The force causing the hammer 24 to move towards the anvil 23 is generated by the slide accelerator 11. The energy stored in the springs 29 is transmitted to the drill collars 16 and

  at the actuating mandrel 22 When the lock 25 is released, the man-

  22, the drill collars 16 and the accelerator tool body.

  12, which are substantially rigidly connected to each other, accelerate rapidly upward as a unitary assembly and the potential energy stored in the springs 29 is converted into kinetic energy. In FIG. 3, the slide 20 is represented at the moment of impact.

  between the hammer 24 and the anvil 23 The impact between the hammer 24 and the

  Clume 23 causes essentially instant stop of the drill collars 16 and the throttle body 12 and results in the transmission of a strong impulse to the stuck object through the

  lower slide 28 of the slide As shown in Figure 3, accelerating

  Slider driver 11 is still in a slightly elongated position and the springs 29 are still slightly compressed. Therefore, at all times before the impact, the accelerator 11 transmits an acceleration to the drill collars 16 and to the actuating mandrel. slide 22,

  In FIGS. 4 a and 4 b, the preferred embodiment of FIG.

  Sliding Accelerator 11 The tool body 12 of the accelerator

  The upper median body 35 is in turn screwed to a lower median body 40. The lower medial body 40 is in turn screwed together with a lower median body 40. lower body which comprises a tool coupling 15 The upper body 30, the upper middle body 35,

  the lower median body 40 and the lower body 45, consequently form

  a unitary body and suitable seals are provided, consisting of double O-rings such as, for example, bushings

  31 and 36 provided in the internal threaded connection between the upper body and

  30 and the upper median body 35, in all the links

  threads which are established between the parts of the body 12,

it is fluid-tight.

  The throttle mandrel 13 has an upper portion 50,

  provided with an upper tool connector 14, and a lower part 60.

  The mandrel upper portion 50 and the mandrel lower portion 60

  are connected together by screwing through a connecting member

  sound 62 Suitable seals, such as gasket 63,

  are provided for sealing the connections between the upper

  50 and the lower part 60 of the mandrel with the connecting member

  62, thus rendering the entire mandrel 13 fluid-tight.

  The shoulder 17 of the body 12 is formed by the lower end

  the upper middle body 35 and an elastic load ring 37

  pos-ee between the lower median body 40 and the lower part of man-

  The lower shoulder 18 is formed by an adjusting nut 61 which is screwed onto a threaded zone 64 of the mandrel lower part. A locking nut 65 is provided for locking and preventing axial movement of the locking nut. The spring chamber 19 therefore comprises the annular gap between the

  lower part of mandrel 60 and the lower median body 40, this

  tervalle being delimited axially by the elastic load ring 37 at one end and the adjusting nut 61 at the other end. The disk-shaped springs 29 comprise a first series 29a of relatively rigid disks and a second series 29b of relatively less rigid disks. The numbers and the respective stiffnesses of the

  springs of series 29a and 29b are chosen in relation to the characteristics

  The springs of the second series 29b are specifically selected so as to have a composite elasticity constant and a length that a compression of the second series springs 29b a distance equal to the stroke of the slide produces a force lower than the latch release load of the slide In other words, the length and the elasticity constant composite of the second series of springs 29 b allow, during running, an elongation of the mandrel 13 relative to the accelerator tool body 12 which is greater than the stroke of the slide, the second series of springs 29 b is arranged so as to have a

  higher composite elasticity than that of first serum 29 a.

  The springs 29 therefore cause the accelerator 11 to have a progressive elasticity characteristic in which a first portion of the elongation of the accelerator 11 (compression of the discs 29)

  length equal to the stroke of the slide shall be established by the

  series spring series 29 b and produce a force less than the force required to release the slide A second part of the elongation of the accelerator 11 is established by compression of the springs of the second

  series 29b over a relatively small distance to produce a

necessary to release the slide.

  The characteristic of progressive elasticity according to the present invention is particularly advantageous in situations where great importance is attached to the length of the slide and the possibility of

  adjustment in a wide range of release forces in such situations.

  the springs of the second series 29b are adjusted so that an extension of the accelerator II of a length equal to the stroke of the

  slide produces a force less than the minimum release force.

  The first set of springs 29a is selected so that an elongation

  relatively small additional amount of the accelerator

  addi tio nal 1 e sufficient to 1 i erate 1 to coul i s s under conditions of re-

  Therefore, the characteristic of elasticity

  Graduality of the accelerator 11-minimizes the

  length of the springs 29 while simultaneously ensuring that the

  along the accelerator It is always superior to the race of the slide.

  For a detailed description of disc-shaped springs,

  reference may be made to the "Precision (Bellville) Disc Springs Engineering Handbook" published by "Key Bellville Inc" RD No. 2, Box 191 C, Leechburg, Pennsylvania. 15656 Disk-shaped springs may be used. of different configurations by changing

  the position of the adjusting nut 61 on the threaded portion 64.

  The volume between the tool body 12 and the chuck 13 of the accelerator, including the spring chamber 19, is preferably

  filled with lubricating oil A set of upper joints of man-

  drin, in particular a seal 51, is provided to establish a seal

  sliding between the upper body 30 and the upper part of man-

  50, in order to isolate the lubricating oil from the external environment.

  The throttle 11 is also provided on each side of the

  seal 51, two protective rings, in particular the protective ring 52.

  The other end of the accelerator 11 is sealed by a free piston 66 which is slidably mounted between the lower mandrel portion and the lower body 45 in a reservoir 67. The free piston 66 is in sealing contact with both the mandrel lower portion 60 and the lower body 45 through a series of seals

  of protective rings, in particular the gasket 68 and the protective ring 69.

  The free piston 66 can move freely to absorb variances

  In addition, the free piston 66 balances the pressure exerted on both sides of the piston to maintain the pressure of the lubricating oil between the tool body 12 and the piston. chuck 13 of the accelerator, in particular the oil in the spring chamber 19, at a level essentially equal to the ambient pressure Since the accelerator 11 operates under a pressure equalization condition,

  a defect affecting any or all of the seals

  has no disturbing influence on the functioning of the acceleration

  11 Failure of a seal may only cause contamination or loss of lubricating oil, but does not prevent the operation of the tool Fill fittings 54 and 55 are

  provided for filling the accelerator 11 with lubricating oil.

  certain embodiments, gaskets and lubricating oil.

  The invention can be omitted so that the spring chamber 19 can communicate directly with the well.

  For a couple to be transmitted via the accelerator

  11, the upper body 30 and the mandrel top 50 have cooperating grooves 57 and 58.

  to use the accelerator 11 with drill slides.

  Of course, the present invention is not limited to the modes

  described and represented, and is likely to

  its variants accessible to the person skilled in the art, without one deviating

of the spirit of the invention.

Claims (15)

  1. retrieval slide accelerator, usable with a slide having a slide release means responsive to stroke and force values, characterized in that it comprises: a tubular tool body (12) of elongate shape and comprising an inwardly directed shoulder (17); an elongate mandrel (13) axially slidably mounted in the tool body (12) and having an axially fixed outwardly directed shoulder (18), said shoulders (17, 18) defining a chamber springs (19) between said mandrel (13) and said body (12); and a plurality of frustoconical disks (29) which   disposed in said chamber around said mandrel and between said shoulders.   Slide accelerator according to claim 1, characterized in that said set of disk-shaped springs (29) comprises   a first series (29a) of springs, this first series having a length   a compression spring at least equal to the stroke of the slide and a composite elastic constant such that the force generated on said compression length is less than the force required to release said slide.   3. Accelerator according to claim 2, characterized in that said set of disk-shaped springs (29) comprises a second   series (29b) of springs, said second series having an elastic constant   greater than the composite elasticity of the first series (29 a).   4. Accelerator according to claim 3, characterized in that the composite elasticity constant of said second series (29b) is   such as a force greater than the force required to actuate the   smooth is generated on a compression length of the second series   which is less than the run of the slide.   5. Accelerator according to claim 1, characterized in that it comprises a means for maintaining at substantially equal values, the pressures respectivelyregnant inside said chamber to   springs (19) and outside said tool body (12) -   6. Accelerator according to claim 5, characterized in that   said holding means comprises a piston (66) mounted so as to cover   smoothly sealing around said mandrel (13) and within said tool body (12).   7. Accelerator according to claim 1, characterized in that it comprises a substantially incompressible fluid filling said chamber (19) and a means (66) for compensating for volume variations of said chamber and for balancing the pressure of the fluid filling said chamber and the pressure prevailing outside the tool body during the   operation of the accelerator (11).   8. Accelerator according to claim 7, characterized in that said compensating and balancing means comprises a closure means mounted so as to be able to move between said mandrel (13) and said tool body (12).   9. Accelerator according to claim 8, characterized in that said closure means comprises a piston (66) mounted so as to be able to move between said mandrel (13) and said tool body (12) and comprising members ( 68, 69) to establish a seal at a time   with the chuck and with the tool body.   10. Accelerator according to claim 1, characterized in that it comprises means for transmitting a torque between said mandrel (13) and said tool body (12).   11 accelerator according to claim 1, characterized in that it comprises means for modifying the spacing between said shoulders (17, 18) so as to allow adaptation to different lengths   series (29a, 29b) of disk-shaped springs;   12. Accelerator according to claim 1, characterized in that it comprises means for establishing a sliding seal between the tool body (12 J and the mandrel (13) at axially opposite ends   of said spring chamber (19), and a substantially incomprehensible fluid   filling the volume between said seals, to   inside the tool body and outside the mandrel.   Accelerator according to claim 13, characterized in that it comprises means for maintaining the pressure of said incompressible fluid substantially constant during the operation of the accelerator, 14. Accelerator according to claim 12, characterized in that it comprises a means for balancing the pressure of said fluid with respect to   the pressure prevailing outside said seals.   15. Accelerator according to claim 14, characterized in that said pressure balancing means comprises a piston (66) whose one end is urged by said fluid, while the other end   is subjected to the pressure prevailing outside said seals.