FR2602818A1 - Safety valve for an oil well, constituent part and accessory equipment - Google Patents

Abstract

The invention relates to a safety valve for an oil well. This valve comprises a movable shutter member 11 located at the bottom part, an internal tubular slide 9 for pushing the said member back in the opening direction, a spring 10 for returning the slide to its top position corresponding to closure, means for hydraulically moving the slide downwards by pressurising a control fluid, seals 15, 16 intended to ensure leaktightness between the valve and its receptacle-sleeve 1, and an anchor bolt V located at the top part above the seals for anchoring the valve in the receptacle-sleeve. The anchor bolt V is assembled onto the valve via a removable fitting sleeve 80 making it possible to equip the valve with a bolt chosen among various existing types.

Description

SAFETY VALVE FOR OIL WELLS,
CONSTITUTIVE PART AND ACCESSORY EQUIPMENT
The invention relates to a safety valve intended to be inserted into an oil well production tube in order to ensure its opening or closing.

The invention extends to constituent parts of said valve and to accessory equipment.

 The safety valves for oil wells have the function of automatically stopping the production of effluent if an incident occurs at the head of the well or downstream from it. They are hydraulically controlled upon opening from the surface and are closed automatically by means of a powerful return spring as soon as a hydraulic pressure drop, commanded or accidental, occurs. These valves have been the subject of numerous development and improvement studies, and their use has become widespread, particularly in offshore eruptive wells.

 When in place, these valves are anchored in a receptacle sleeve housed in the production tube by means of an anchor lock. Existing anchor locks include dogs capable of undergoing radical expansion to penetrate during anchoring in a groove of the receptacle sleeve. Each manufacturer has a specific type of lock, locking is generally effected by means of a locking ring which is pushed back by a spring inside the above-mentioned dogs.

 In addition, in an application for hrevet filed simultaneously by the applicant, a valve with a new and improved structure is described providing the user with several essential advantages: reduction of corrosion phenomena, easy and safe assembly and disassembly, easy change of the seals. most exposed ...

 The present invention proposes to enable such an improved valve to be fitted, by means of an anchoring lock chosen by the manufacturer or the user from among the various existing types. The invention thus aims to give the professional the free choice of the lock he wishes to implement, while offering him the possibility of enjoying the advantages of the new valve referred to above.

 In order to facilitate understanding, the valve according to the invention is described by assuming it to be in place in an oil well, the terms "top", "bottom", "upper", "lower" referring to this position.

The safety valve targeted by the invention is of the type comprising
a valve body of general tubular shape,
an anchor lock located in the upper part of the valve body and adapted to secure it in a receptacle sleeve housed in the production tube, said anchor lock comprising a tubular lock body tapped at its base, means stop in the receptacle sleeve and radially movable dogs in order to be able to penetrate, in the stop position, into an anchoring groove of said receptacle sleeve,
a movable obturatron member located in the lower part of the valve body and biased towards the closed position,
a tubular slide arranged to be able to slide longitudinally inside the valve body in order to generate in its downward movement the opening of the shutter orqane,
a return spring disposed in an annular housing located between the slide and the valve body, so as to urge said slide towards a high position corresponding to the closing of the shutter member,
means for hydraulic displacement of the slide downward, comprising an inlet for control fluid through the receptacle sleeve and the valve body, as well as a sealed volume between slide and body intended to receive the control fluid, the slide having a difference in section subjected to the pressure of the fluid contained in said sealed volume so as to undergo a downward force when said volume is under pressure,
sealings, lower and upper, arranged around the valve body in order to ensure a seal at the interface between said valve body and the receptacle sleeve at levels located below and above the arrival of the control fluid.

According to the present invention, the valve is characterized in that
a removable adapter sleeve is assembled on the valve body above the upper seal,
said adapter sleeve is provided, at its upper end, with a threaded collar adapted to allow the screwing of the lock body chosen by its tapped base,
said adapter sleeve has a height adapted to the selected latch so that, in its screwed position, the dogs of said latch come opposite the anchor qorqe of the receptacle sleeve when the valve body is in place in said sleeve -receptor with the arrival of fluid in communication with the aforementioned sealed volume,
the return spring is positioned below the lower seal (opposite the lock body with respect to the seal) in an annular housing formed by a part of the sealed volume intended to receive the control fluid.

 Thus, the professional can choose from a set of adapter sleeves the one that corresponds to the anchor lock he wishes to implement from the different types present.

 At their base, these adapter sleeves comprise means of assembly with the valve, identical for all the sleeves; when a sleeve is put in place, these means cooperate with combined means provided on the valve body above the upper seal.

 At its upper end, each adapter sleeve is provided with a threaded collar adapted to the type of lock to which it corresponds, in order to allow the screwing thereof; thanks to the appropriate height of the adapter sleeve, the dogs of the bolt (once it is screwed onto said sleeve) have a position suitable for facing the anchoring groove of the receptacle sleeve when the valve is put in place in the latter. The anchoring and locking of the valve can thus be obtained by means of the desired lock.

 The return spring (called to cause the valve to close in the event of a pressure drop in the control fluid) is located opposite the latch with respect to the seals, which allows mounting and operation independent of said lock. This spring, housed in the sealed volume containing the control fluid, is permanently lubricated by this fluid and is sheltered from the aqressions of the effluent from the well.

Furthermore, as for the valve described in the patent application filed simultaneously, the valve body advantageously consists of several tubular parts, secured to each other, comprising
an upper seal holder, provided in the upper part with the aforementioned assembly means, said upper seal holder being provided externally with a notch for insertion of the upper seal and being pierced at a lower level with a control fluid inlet light,
a spring jacket, extending around the return spring and screwed by an upper heel to the upper seal carrier, said upper heel being externally provided with a notch for insertion of the lower seal,
a tubular spacer, extending around the upper seal carrier between the seals, lower and upper, said spacer being pierced with a lumen corresponding to the inlet lumen of the control fluid.

 This structure facilitates the changing of the seals and, more generally, the maintenance of the valve.

 In the most widespread case where the anchoring locks called to be put in place are provided with a clean spring urging a locking ring, the threaded collar of each adapter sleeve preferably has an internal upper flange, suitable for guiding the lower end of the lock spring.

Other characteristics, objects and advantages of the invention will emerge from the description which follows with reference to the appended drawings, which present by way of non-limiting example a preferred embodiment in these drawings which form an integral part of this description.
FIG. 1 is a view in axial section of a valve, called to be equipped with an anchoring lock by means of an adapter sleeve,
FIG. 2 is a detail half-section of said valve,
FIG. 3a is a diagrammatic view in partial axial section of an anchoring lock and FIG. 4a a view in axial section of the corresponding adapter sleeve,
FIG. 3h is a diagrammatic view in partial axial section of another anchor bolt and FIG. 4h a view in partial section of the corresponding adapter sleeve,
- Finally, Fiqure 5 is an axial sectional view of the complete valve, anchored in a receptacle sleeve, in the open position.

 The safety valve, shown without its lock in Figures 1 and 2 and with it in Figure 5, is intended to equip a production tube with an oil well.

This well is conventionally provided with a receptacle sleeve 1 (FIG. 5) which is provided with an inlet line for control fluid 1a, an anchoring groove 1b and stop means (symbolized in A and constituted in a conventional manner by a shoulder against which abuts a conjugate shoulder of the lock body).

 The valve comprises a lower part P as shown in FIG. 1, an anchoring lock V known in itself, which can be chosen from several existing types VA, Vu ... (as shown diagrammatically in Figures 3a and 3b ), and an adapter sleeve 80 chosen from a set 80A 8û ... (as shown in Figures 4a and 4b).

 The lower part P comprises a valve body of generally tubular shape, consisting of several tubular parts secured to each other: upper seal holder 3, tubular spacer 4, ring-locking nut 5, spring jacket 6, lower sleeve 7, body shutter 8.

 Inside the valve body is mounted a tubular slide 9 able to move longitudinally in the valve body, between a low position (corresponding to the opening) shown in FIG. 5 and a high position (corresponding to the closure) shown in Figure 1. This slide is returned to its upper position by a return spring 10 and is hydraulically controlled downwards by the control fluid arriving by the line la, when the latter is pressurized.

 In the lower part, the shutter body R comprises a movable shutter member, constituted in the example by a valve 11 which is articulated on said body so as to be able to pivot between an open position retracted on the side (fig. 5) and a closed position where said valve closes the valve body by applying against a seal carried by it (Figure 1). The valve 11 is returned to the closed position by a spring 12 disposed around its axis of articulation. It should be noted that this shutter member, known in itself, can be of another type and in particular a ball member in which the shutter is provided by a spherical part able to move longitudinally with a rotation associated, between an open position and a closed position (a spring recalling the ball to the latter position).

 Under the effect of the hydraulic control, the slide 9- is moved to its low position until it comes into abutment with the valve nose 8a: said slide then pushes the shutter member 11 and maintains it in the position d 'opening. When the pressure of the control fluid accidentally or voluntarily drops, the return spring 10 generates a displacement of the slide upwards, to its high position where it is set back in the lower sleeve 7 (FIG. 1). The shutter member 11 is then released and closes under the action of its own spring 12.

 Conventionally, the lower sleeve 7 is equipped with a balancing valve 13 which is actuated, during opening, at the start of the descent of the slide, by a cam 9a of the latter, in order to allow pressure balancing below and beyond the shutter member 11.

Furthermore, the upper seal holder 3 is provided at the top with a threaded assembly collar 3c around which is called to screw the adapter sleeve.
V. This seal carrier is internally provided with a groove in which is housed an upper seal 21 coming into contact with the slide 9.

 Externally, the seal carrier 3 is provided with a notch which opens downwards and whose shape is adapted to allow the insertion of an upper sealing gasket 15. This gasket, in particular of the A chevron type , is located immediately above a light 3a for the arrival of the control fluid, -which is pierced the upper seal holder.

 The gasket 15 is locked in its notch by the tubular spacer 4 which extends around the upper seal holder 3 and is itself pierced with a light 4a for the arrival of the control fluid. The lights 3a and 4e correspond and come into correspondence with the finish line la of the sleeve-receptacle when the valve is in place in the latter.

 Furthermore, the spring jacket 6 which extends around the return spring 10 is screwed onto the upper seal holder 3 by an upper heel 6a. This heel is provided externally with a notch which opens upwards and whose shape is adapted to allow the insertion of a lower sealing gasket 16. This gasket, in particular of the herringbone type, is thus positioned immediately below the fluid inlet lights it is locked in its notch by the nut ring 5 which is screwed around the upper seal holder 3. This nut ring 5 also ensures the tubular spacer 4 is blocked ( the lower part of which bears against the upper edge of said ring-nut); moreover, it constitutes an end of screwing stop for the heel 6a of the shirt 6.

 This 6th heel forms at its base an internal shoulder which limits the upward movement of the slider 9 by forming a stop for the ring-nut 19 mentioned below.

 In the lower part, the spring jacket 6 is screwed around the lower sleeve 7 which forms a shoulder 7a inside said shirt. A seal 17 is interposed to seal the valve body at this level.

 The return spring 10 is positioned below the seals 15 and 16 in an annular loqement delimited by the external face of the slide 9 and the internal face of the jacket 6.

The upper end of this spring 10 abuts against an auxiliary mounting ring 18 which is mounted around the slider 9 so that it can slide along the latter. This auxiliary ring has on its periphery an imprint 18a, in particular a circular groove, allowing
immobilize it during assembly, as described in an FR patent application filed simultaneously by the applicant.

 The auxiliary ring 19 comes into the high position in abutment against a hague-nut 19 screwed around the slider 9 which is provided for this purpose with a thread on an area of its external surface. At the end of screwing, the nut ring 19 comes into abutment against a small shoulder 9h formed on the external surface of the slide between two sections of different diameter.

 The lower end of the spring 10 comes to bear against a lower bush 20 slidably mounted around the slider 9. a lower stop 9c limits the downward stroke of said bush 20 relative to the slider. This stop 9c is formed by a shoulder formed on the external surface of the slide 9 between two sections of different diameters; the sleeve 20 has a two-section bore comprising an abutment face against said shoulder.

 In addition, in its low position relative to the valve body, this sleeve 20 is applied against the internal shoulder 7e formed by the upper edge of the sleeve 7.

 In addition, the sleeve 20 has on its periphery an imprint 20b, in particular a circular groove, allowing it to be immobilized during assembly, in the same way as the auxiliary ring 18. (Reference may be made to the simultaneous patent application for more details on assembly).

 Furthermore, the control fluid, consisting of a lubricating liquid, arrived in the valve body by the line la and the ports 4e and 3a, is stopped at the valve body / sleeve-receptacle interface by the seals. 15 and 16 located immediately on either side of said inlet lights and fills a sealed volume located between the slide and the valve body.

 This sealed volume is limited, at the slide / valve body interface, on the one hand, by the upper seal 21 disposed above the arrival of the fluid in abutment against an upper section of the slide of predetermined diameter. , on the other hand, by a lower seal 22 arranged in a groove below and in the vicinity of the lower end of the return spring 10, bearing against a lower section of the slider with a diameter larger than that of the above-mentioned upper section.

 The difference in diameter between these two sections of slide is defined by the shoulders 9h and 9c already mentioned: the control fluid thus acts down on the slide through these differences in section.

 The lower seal 22 is arranged in a groove in the sleeve 7 so as to be positioned below and near the sleeve 20. The seals 21 and 22 are in particular O-rings.

 The above-mentioned structure has the numerous advantages described in the simultaneous patent application: effective lubrication of the return spring and of the moving parts which are isolated from the tributary and corrosive gases, disassembly of the valve without danger of relaxation of the return spring, easy assembly of the spring by means of a tool, simplification of maintenance in particular thanks to the ability to quickly change the seals 15 and 16 on site (which are the most exposed due to friction suffered during lowering the valve in the well) ...

 The set of adapter sleeves 80A, 80fol ...

allows the VA, V ... anchor lock chosen to be adapted to the improved valve described above.

 These conventional locks comprise a tubular lock body 90, provided with a threaded base 91 and in which is housed the anchoring system, generally composed of a spring 92, of a locking ring 93 (visible in FIG. 5 ) urged upwards by the spring 92 and radially elastic dogs symbolized at 94 which are called upon to be inserted into the dreary lb of the receptacle sleeve 1, the ring 93 ensuring mechanical locking of these. These valve locks are well known and will not be described in more detail.

 Each adapter sleeve 8 n or 80G (FIGS. 4a, 4h) is provided with a tapped lower end 81, combined with the assembly collar 3c of the valve in order to be able to be screwed around it.

 In addition, each sleeve check is provided at its upper end with a threaded collar 82 surmounted by an internal rim 83 intended to guide the lower end of the lock spring 92. The pitch and the diameter of the thread of the collar 82 are adapted to the pitch and to the diameter of the tapped thread 91 of the lock with which said sleeve is intended to cooperate. Similarly, the height of the adapter sleeve is adapted to this lock so that, once the valve, the sleeve d adaptation and the lock assembled and arranged in normal position in the receptacle sleeve, the dogs 94 of said lock come opposite the anchoring groove lb of the receptacle sleeve; in this position, the arrival line of the control fluid 1a is in communication with the openings 3a, 4a which allow the passage of the fluid towards the internal volume of fluid of the valve (sealed volume already mentioned situated between the slide and the body and limited by seals 21 and 22 at the interface of these elements).

 FIG. 5 shows a valve according to the invention, equipped with a lock V of a type known by the intermediary of the corresponding adapter sleeve 80.

This valve is shown anchored in its receptacle sleeve 1, in the open position: the sealed volume containing the control fluid is under pressure and keeps the slide 9 in the low position. The return spring 10 is compressed and completely immersed in the control fluid, without contact with the effluent.

Claims (8)

 1 / - Safety valve intended to be inserted in an oil well production tube in order to ensure opening or closing, said valve comprising  a valve body of generally tubular shape,  an anchor lock (V) located in the upper part of the valve body and adapted to secure it in a receptacle sleeve (1) housed in the production tube, said anchor lock comprising a tubular lock body ( 90) tapped at its base (91), stop means (A) in the receptacle sleeve and dogs (94) radially mohile in order to be able to penetrate, in the stop position, into an anchoring groove ( lob) of said receptacle sleeve,  a movable closure member (11), located in the lower part of the valve body and urged towards its closed position,  a tubular slide (9) arranged to be able to slide longitudinally inside the valve body in order to generate in its downward movement the opening of the shutter member,  a return spring (10) disposed in an annular housing located between the slide and the valve body, so as to urge said slide (9) towards a high position corresponding to the closing of the shutter member,  means for hydraulic displacement of the slide downwards, comprising an inlet for control fluid (la, 3a, 4a) through the receptacle sleeve and the valve body, as well as a sealed volume between slide and body intended to receive the control fluid, the slide having a difference in section subjected to the pressure of the fluid contained in said sealed volume so as to undergo a downward force when said volume is under pressure,  seals, lower (16) and upper (15), disposed around the valve body in order to ensure a seal at the interface between said valve body and the receptacle sleeve at levels located below and at above the arrival of the control fluid, said valve being characterized in that  a removable adapter sleeve (80) is assembled on the valve body above the upper seal (15),  said adapter sleeve is provided, at its upper end, with a threaded collar (82) adapted to allow the screwing of the lock body chosen by its tapped base (91),  said adapter sleeve has a height adapted to the selected lock so that, in its screwed position, the dogs (94) of said lock come opposite the anchoring groove (lb) of the receptacle sleeve (1) when the body valve is in place in said sleeve-receptacle with the fluid inlet (la) in communication with the aforementioned sealed volume,  the return spring (10) is positioned below the lower seal (16) (3 opposite the lock body relative to the seal) in an annular housing formed by a part of the sealed volume intended to receive the control fluid.  2 / - Safety valve according to claim 1, characterized in that  the valve body has, above the upper seal (15), a threaded collar (3c) for assembling the adapter sleeve,  the lower end (81) of said adapter sleeve is tapped so as to be able to be screwed onto said threaded collar (3c).  3 / - Safety valve according to claim 2, characterized in that the valve body consists of several tubular parts, secured to each other, comprising  an upper seal holder (3), provided in the upper part with the threaded assembly collar (3c), said upper seal holder being provided externally with a notch for insertion of the upper seal (15) and being drilled at a lower level of an inlet light for the control fluid (3a),  a spring jacket (16), extending around the spring (10) and screwed by an upper heel (6fol) on the upper seal carrier (3), said upper heel being externally provided with a notch for insertion of the lower seal (16),  a tubular spacer (4), extending around the upper seal carrier (3) between the seals, lower (16) and upper (15), said spacer being pierced with a lumen (4a) in correspondence with the inlet light for the control fluid (3a).  4 / - Safety valve according to claim 3, characterized in that the sealed volume intended to receive the control fluid is limited to the interface between the slide and the valve body  on the one hand, by an upper seal (21) disposed above and near the inlet of the control fluid (3a, 4a), in a groove in the upper seal holder (3), in abutment against an upper section of the slide of predetermined diameter,  on the other hand, by a lower seal (22), arranged below and in the vicinity of the lower end of the return spring (10), in a groove of the valve body, bearing against a lower section of the slide with a larger diameter than that of the above-mentioned upper section.  5 / - Safety valve according to claim 4, characterized in that the tubular spacer (4) is blocked at its lower part by a ring-nut (5) screwed around the upper seal holder (3), said ring- nut retaining the lower seal (16) and forming a stop for the heel (6a) of the spring jacket.  6 / - Safety valve according to one of claims 1, 2, 3, 4 or 5, equipped with an anchor lock (V) with spring, characterized in that the threaded collar (82) of the sleeve adaptation has an internal upper flange (83), adapted to guide the lower end of the lock spring (92).  7 / - Set of adapter sleeves for the production of a valve according to one of claims 1 to 6, equipped with an anchoring lock chosen from several types (VA, V ...), characterized in that  the adapter sleeves (80A 80p--) comprise, at their base, means (81) for assembly with the valve, identical for all the sleeves,  each sleeve is provided, at its upper end, with a threaded collar (82) adapted to a type of lock determined in order to allow the screwing thereof, said sleeve having a height adapted to said lock.  8 / - Valve body capable of being fitted with an anchoring lock chosen from several types (VA, V, etc.), characterized in that it comprises, at its upper end, assembly means (3c) adapted to authorize the assembly of each of the adapter sleeves of the set referred to in claim 7.