EP0854967B1 - Method and devices for making safe an oil well in the event of a defect in the hydraulic control line of its bottom safety valve - Google Patents

Description

The invention relates to a delivery method in safety of an oil well equipped with a valve bottom safety with hydraulic control line faulty. It extends to a special bottom valve of safety and various means of implementing the process: new command line, enhancement element of the wellhead, tools and methods of laying or removal of the new command line.

We know that, for security reasons, oil wells are generally equipped with shut-off valves bottom safety which are inserted in a receptacle sleeve housed in the production tube of the well at a few tens or hundreds of meters deep; the function of these valves is to stop automatically produce effluent if an incident occurs at the wellhead or downstream of it. They are hydraulically controlled upon opening from the surface and close automatically with a powerful spring as soon as a fall occurs hydraulic pressure on the control line, that this fall either controlled or accidental. This line of hydraulic control consists of a pressurized fluid that runs outside the tube production (between the latter and the external casing) and is connected, on the one hand, at the surface to a fluid supply, on the other hand, at the valve, to a channel which passes through the receptacle sleeve containing the valve for feed it. This type of system is now used in virtually all wells, including off shore eruptive wells.

Sometimes this command line hydraulic system has faults (leak, blocked line or broken): the safety valve can no longer be supplied with pressurized fluid and no longer plays its role; it generally remains closed under the action of its comes out and closes the passage of the effluent.

Two solutions are currently available to the operator to remedy this deficiency. he can extract the safety valve from the production tube (after installation of a well head airlock) and then close the faulty command line by setting up in the production tube an insulation jacket with seals which isolate the arrival of the control through the receptacle sleeve. The well can again operate but it is then outside the safety standards since it is no longer equipped with a background security. Another solution avoiding this extraordinary operation consists in "killing" the well, that is to say to reconstitute it entirely by balancing effluent pressure with mud, extracting the entire production tube and its equipment and by casing the well again (like a new well) with implementation of a new type command line traditional and a new safety valve, exactly as in a new well. This solution which then allows you to work according to safety standards, is extremely heavy and expensive.

Furthermore, it is proposed in the patent US 4,844,166 to avoid killing the well, by setting up a continuous tube inside the production tube existing and housing the necessary equipment (valve security, command line ...) in the annular volume located around this continuous tube.

The present invention provides a solution news to restore safety to an oil well including the hydraulic control line is faulty, without have to kill the well and retub it. The objective of the invention is to equip the well with a new safety with hydraulic control independent of the line original order, respecting safety standards, and this, by implementing a procedure considerably lighter than the second solution mentioned above.

To this end, one of the objects of the invention is to provide a new bottom safety valve, so-called special valve, as well as various equipment (new command line, installation tools and methods or to remove the new line of command) which allow the implementation of the safety targeted by the invention.

• par "tube de production", le tube situé au centre du puits pour guider les effluents (tubing),
• par "manchon-réceptacle", le manchon qui est intercalé sur le tube de production pour recevoir la vanne de sécurité de fond (nipple),
• par "tubage externe", la gaine tubulaire située autour du tube de production pour l'isoler du terrain (casing),
• par "ensemble de suspension", la partie (hanger) située à l'extrémité supérieure du tube de production et du tubage externe et qui relie mécaniquement ces deux éléments (en anglais "spool" ou "tubing hanger"),
• par "tête de puits", le système de vannes et robinets qui équipe le puits au-dessus de l'ensemble de suspension (well head).

Conventionally, we will designate below (the corresponding English term is indicated in parentheses):

• "production tube" means the tube located in the center of the well to guide the effluents (tubing),
• by "receptacle sleeve", the sleeve which is interposed on the production tube to receive the bottom safety valve (nipple),
• by "external casing", the tubular sheath located around the production tube to isolate it from the ground (casing),
• "suspension assembly" means the part (hanger) situated at the upper end of the production tube and the external casing and which mechanically connects these two elements (in English "spool" or "tubing hanger"),
• by "wellhead", the system of valves and taps which equips the well above the suspension assembly (well head).

The process according to the invention for restore an oil well equipped with a valve safety valve - said original valve - including the hydraulic control - said original line - is defective, consists in replacing the original valve with a special bottom valve comprising, along its axis and in the upper part, hydraulic connection means, to its periphery, means for isolating or sealing so waterproof the original command line, and in part low, a movable shutter member operable at closing by action of a fluid under pressure arriving axially by the hydraulic connection means, install inside the production tube, along the axis of it, a new command line hydraulic, called concentric control line, and connect said concentric control line to the means hydraulic connection of the special valve.

So without changing the production tube and its equipment, the method of the invention makes it possible to provide the well with new bottom security, including the originality is to be ordered by an internal line at production tube, the original line being disused (line which passes through the receptacle sleeve and goes up towards the surface between the production tube and the casing external). Once in place, the special valve isolates or shut off the arrival lights of this original line at through the receptacle sleeve. The special valve fills then exactly the same role as a safety valve traditional and allows operation of the well meets safety standards.

• un corps de vanne de forme générale tubulaire,
• un organe mobile d'obturation (flapper) situé en partie basse dudit corps et sollicité vers sa position de fermeture,
• un coulisseau tubulaire (flow tube) agencé pour pouvoir coulisser longitudinalement à l'intérieur du corps de vanne en vue d'engendrer dans son mouvement descendant l'ouverture de l'organe d'obturation,
• des moyens élastiques de rappel agencés pour solliciter ledit coulisseau vers une position haute correspondant à la fermeture de l'organe d'obturation,
• un système d'ancrage situé en partie haute du corps de vanne et adapté pour assujettir celui-ci dans un manchon réceptacle logé dans le tube de production,
• des moyens d'étanchéité disposés sur la face externe du corps de vanne de façon à assurer une isolation de la ligne hydraulique de commande d'origine du tube de production.

The special bottom valve used in the process of the invention preferably comprises the following means:

• a valve body of generally tubular shape,
• a movable shutter member (flapper) located in the lower part of said body and urged towards its closed position,
• a tubular slide (flow tube) 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,
• elastic return means arranged to urge said slide towards a high position corresponding to the closing of the shutter member,
• an anchoring system located in the upper part of the valve body and adapted to secure it in a receptacle sleeve housed in the production tube,
• sealing means arranged on the external face of the valve body so as to insulate the original hydraulic control line from the production tube.

• un piston interne s'étendant le long de l'axe du corps de vanne,
• un poussoir porté par la partie inférieure du piston interne et agencé dans le corps de vanne au-dessus et au contact du coulisseau de façon à pouvoir repousser ledit coulisseau vers le bas lors d'un déplacement descendant du piston interne,
• une douille axiale solidaire du corps de vanne et agencée le long de l'axe de celui-ci pour recevoir à coulissement la partie supérieure du piston interne,
• des moyens d'étanchéité entre piston interne et douille axiale,
• des moyens de connexion hydraulique de l'extrémité supérieure de la douille avec une ligne hydraulique de commande s'étendant à l'intérieur du tube de production.

Said special valve is characterized in that it comprises, combined with the above means:

• an internal piston extending along the axis of the valve body,
• a pusher carried by the lower part of the internal piston and arranged in the valve body above and in contact with the slide so as to be able to push said slide down during a downward movement of the internal piston,
• an axial sleeve integral with the valve body and arranged along the axis of the latter to slide the upper part of the internal piston,
• sealing means between the internal piston and the axial sleeve,
• means for hydraulic connection of the upper end of the sleeve with a hydraulic control line extending inside the production tube.

Preferably, the pusher is constituted by a section of tube sliding in the valve body and carried by the internal piston thanks to radial arms which make it integral with it.

According to a preferred embodiment, the hydraulic connection means comprising a connector male, mounted at the head of said socket and suitable for cooperate with a conjugate female connector integral with the hydraulic control line.

The valve anchoring system can be a mechanical system of known type, comprising particular anchor dogs, a socket of locking dogs and a spring return the socket.

(a) montage d'un sas sur la tête de puits,

(b) extraction de la vanne d'origine pour libérer le tube de production,

(c) mise en place au fond du puits d'un bouchon ("plug"),

(d) mise en place dans le manchon-réceptacle du tube de production, d'une vanne de sécurité classique en position fermée,

(e) montage au-dessus du tube de production d'un clapet anti-retour ("BPV : back pressure valve"),

(f) démontage de la tête de puits et du sas,

(g) mise en place au-dessus du clapet anti-retour, d'un élément de rehausse de tête de puits comprenant en attente des moyens pour la fixation de la ligne de commande concentrique et des moyens pour le passage du fluide vers ladite ligne,

(h) remise en place de la tête de puits et du sas,

(i) dépose du clapet anti-retour,

(j) extraction de la vanne de sécurité classique et du bouchon de fond de puits pour libérer le tube de production,

(k) mise en place de la vanne de fond spéciale,

(l) mise en place de la ligne de commande concentrique de ladite vanne spéciale,

(m) test de pression sur la ligne de commande concentrique pour vérifier l'ouverture de la vanne spéciale,

(n) démontage du sas sur la tête de puits.

The procedure for replacing the original valve with the special valve defined above and for installing the concentric control line advantageously comprises the following successive operations:

(a) mounting an airlock on the well head,

(b) extraction of the original valve to release the production tube,

(c) placing a plug at the bottom of the well,

(d) installation in the sleeve-receptacle of the production tube, of a conventional safety valve in the closed position,

(e) mounting above the production tube of a non-return valve (BPV: back pressure valve),

(f) disassembly of the wellhead and the airlock,

(g) placing, above the non-return valve, a well head raising element comprising, pending, means for fixing the concentric control line and means for the passage of the fluid towards said line ,

(h) replacing the wellhead and airlock,

(i) removing the non-return valve,

(j) extraction of the conventional safety valve and the downhole plug to release the production tube,

(k) installation of the special bottom valve,

(l) installation of the concentric control line of said special valve,

(m) pressure test on the concentric control line to check the opening of the special valve,

(n) disassembly of the airlock on the well head.

Such a procedure respects the rule of three-barrier safety: when the head of well is deposited, the well is protected by three barriers of security ; at the bottom of the well, by the plug ("plug"); at an intermediate depth, by the classic valve temporarily installed in operation (d); in surface, by the non-return valve ("BPV"). The operations (a) - (f), (h) - (j), (m), (n), are classical operations in themselves which are of rapid execution, without difficulty, and use conventional devices well known to oil well professionals. The operations (g): installation of the raising element, (k): installation of the special bottom valve, and (l): setting up the command line are themselves of easy execution as will be understood better below, so the whole refitting procedure security can be performed without any particular difficulty by qualified personnel in a few hours, and this in full compliance with safety standards and rules.

In particular, the special bottom valve can be installed using a standard cable descent, equipped with means for attaching said valve and means for holding its shutter member in the open position. This procedure is well known to professionals to install a bottom safety valve in an oil well.

The wellhead riser element is intended to be fixed on the suspension assembly of the tube production to allow, on the one hand, the maintenance control line mechanics concentric to inside the production tube, on the other hand, the hydraulic supply of this line. To this end, this riser element includes, in particular, a lateral channel fluid passage which will be used to supply the line, as well as retaining means which are arranged for present two positions: a retaining position where they maintain the command line, and a withdrawal position where they allow free passage central.

Another object is to supply a new hydraulic control line, called concentric command line, called to be set place for operation (l) along the axis of the production tube to order the special safety valve previously defined. According to the invention, this line comprises, on the one hand, a plurality of sections, called common sections, intended to be placed end to end on along the axis of the production tube, on the other hand, a upper section intended to be disposed at the end upper of the current sections, finally a head system intended to be hung on the head extension element of well already mentioned.

Preferably, each running section of said line comprises, from top to bottom, a male connector, a first hollow connector holder at the upper end to which the male connector is attached, a first centering device arranged around the first connector holder for center it in the production tube of the well, a hydraulic connection tube secured to the end bottom of the first connector holder, a second connector holder hollow attached to the lower end of the hydraulic link, a second centralizer arranged around the second connector holder to center it in the tube well production, and a subject female connector at the lower end of the second connector holder.

The upper section of the line has a tubular sleeve, a male connector and a connector female respectively subject to the upper end and at the lower end of said tubular sleeve, and at minus a centering device arranged around the tubular sleeve for center it in the production tube of the well.

Finally, the line head system includes a suspension block adapted to be housed in the raising element, integral fastening means of the upper part of said suspension block for the purpose of its attachment by means of a fitting or removal tool, a socket extending downwards and secured under the suspension block to slide the sleeve tubular upper section, sealing means between socket and tubular sleeve, connecting means hydraulic connecting, through the block of suspension, said socket and the passage means of fluid from the riser, and fins from centering secured around the socket to center this in the production tube of the well.

According to other characteristics the male connector of each section of line (current sections or upper section) is identical to special valve male connector and includes essentially a connector body provided with a nose penetration into a female connector and pierced longitudinally of a hydraulic passage, structures anchoring the connector nose in the female connector, a valve for closing the hydraulic passage, means elastic bands urging the valve towards its position closure, and a valve stem housed in the nose of the connector to push the valve back to the position when the male connector is connected in a female connector.

The female connector of the line sections is conjugated with the male connector described above and includes a connector body provided with a housing for the nose of a male connector and pierced longitudinally with a hydraulic passage, a movable anchor in the transverse direction between a corresponding anchoring position locking of the male connector anchoring structures and an erasing position where it releases said anchoring structures, elastic means urging the anchoring member towards its anchoring position, a internal structure for erasing the anchoring member under the pressure of the nose of a male connector, a cam unlocking protruding from the periphery of the body connector to erase the organ anchoring and unlocking connectors under the effect pressure from a sliding surface around the connector, a valve for closing the passage hydraulic, elastic means biasing said valve to its closed position, and a stem valve housed in the body for operating the valve towards its open position when the male connector is anchored in the female connector.

Such connectors, male and female, are able to cooperate and lock to each other, by one touch, safe, automatic and waterproof. Before locking, they are closed by their valve or valve, which prevents pollution of sections of the line control (or the internal tube of the special valve) by the effluent present in the production tube. Their opening takes place at the end of locking and allows passage of control fluid.

In addition, each female connector can be unlocked by external pressure from a surface on its unlocking cam. The installation of sections of line in the production tube can thus be ensured, section by section, using a lowering device with standard type cable, equipped with a laying tool provided such a female connector at the bottom. This connector female will be hooked on the male connector of the section of line in order to get off this one. At the end of the descent, after locking the female connector of said section on the male connector of the lower section already in place (or the special valve for the first section installed), a shear pin provided with the tool pose is sheared by threshing and releases a sleeve of unlocking equipping said fitting tool: this sleeve acts on the unlocking cam of the female connector of the installation tool and the latter, released, can be reassembled and rearmed with a new pin for setting in place for the next section.

In addition, the removal of each section of line can be carried out by means of a device of descent to similar cable, equipped with a removal tool comprising a push tube. The latter will be used to unlock the line section to be removed, from lower section, by acting on the cam unlocking of its female connector (through section centralizers as will be better understood more far).

Thus, the invention allows, by simple and usual operations for oil well professionals, to restore safety of an oil well by respecting the standards of security and execute all necessary procedures on the new installation, in particular the removal of the special bottom valve and that of the control line concentric when needed.

• les figures 1 à 10 sont des schémas illustrant les diverses phases du procédé conforme à l'invention de remise en sécurité d'un puits pétrolier,
• les figures 11 et 12 sont des coupes axiales d'une vanne de fond spéciale conforme à l'invention, respectivement en position fermée et en position ouverte,
• les figures 13 et 14 sont des coupes transversales de ladite vanne spéciale par des plans A et B,
• la figure 15 est une vue de détail, en coupe axiale, du connecteur mâle équipant ladite vanne spéciale,
• la figure 16 est une coupe axiale d'un élément de rehausse de tête de puits, fixé sur l'ensemble de suspension du puits, le système de tête de la ligne de commande hydraulique étant représenté en place dans ledit élément de rehausse,
• la figure 17 est une coupe transversale par un plan C de l'ensemble représenté à la figure 16,
• les figures 18, 19 et 20 sont des coupes axiales respectivement du système de tête, du tronçon supérieur, et d'un tronçon courant d'une ligne de commande concentrique conforme à l'invention,
• la figure 21 est une vue de détail en coupe d'un tronçon courant en position de déverrouillage,
• la figure 22 est une vue de détail en coupe axiale du connecteur femelle équipant les tronçons de la ligne,
• la figure 23 est une vue de détail en coupe axiale montrant un connecteur femelle et un connecteur mâle accouplés et verrouillés,
• les figures 24 et 25 illustrent l'opération de mise en place de la vanne spéciale dans le manchon-réceptacle du puits, au moyen d'un outil de pose,
• les figures 26 et 27 sont des coupes transversales par des plans D et E de la vanne spéciale et de l'outil de pose dans la position de la figure 24,
• les figures 28 et 29 sont des vues de détail en coupe d'un outil de pose de ligne de commande concentrique, respectivement en position armée et en position déverrouillée,
• les figures 30, 31 et 32 illustrent les opérations de pose d'un tronçon de ligne de commande dans le tube de production du puits,
• la figure 33 illustre la pose du système de tête de ladite ligne de commande concentrique,
• la figure 34 est une coupe axiale d'un outil de dépose d'un tronçon de ligne de commande concentrique, et la figure 35 en est une coupe par un plan transversal F,
• la figure 36 illustre l'opération de dépose d'un tronçon de ligne de commande concentrique,
• enfin, les figures 37, 38, 39 et 40 illustrent les opérations de dépose d'une vanne spéciale conforme à l'invention.

Other characteristics, objects and advantages of the invention will emerge from the description which follows, with reference to the appended drawings, which present, without limitation, an exemplary embodiment; on these drawings:

• FIGS. 1 to 10 are diagrams illustrating the various phases of the process according to the invention for restoring an oil well,
• FIGS. 11 and 12 are axial sections of a special bottom valve according to the invention, respectively in the closed position and in the open position,
• FIGS. 13 and 14 are cross sections of said special valve by planes A and B,
• FIG. 15 is a detail view, in axial section, of the male connector fitted to said special valve,
• FIG. 16 is an axial section of a well head raising element, fixed to the suspension assembly of the well, the head system of the hydraulic control line being represented in place in said raising element,
• FIG. 17 is a cross section through a plane C of the assembly shown in FIG. 16,
• FIGS. 18, 19 and 20 are axial sections respectively of the head system, of the upper section, and of a current section of a concentric control line according to the invention,
• FIG. 21 is a detailed view in section of a current section in the unlocked position,
• FIG. 22 is a detail view in axial section of the female connector fitted to the sections of the line,
• FIG. 23 is a detail view in axial section showing a female connector and a male connector coupled and locked,
• FIGS. 24 and 25 illustrate the operation of placing the special valve in the sleeve-receptacle of the well, by means of a setting tool,
• FIGS. 26 and 27 are cross sections through planes D and E of the special valve and of the setting tool in the position of FIG. 24,
• FIGS. 28 and 29 are detailed sectional views of a concentric control line fitting tool, respectively in the armed position and in the unlocked position,
• FIGS. 30, 31 and 32 illustrate the operations of laying a section of control line in the production tube of the well,
• FIG. 33 illustrates the installation of the head system of said concentric control line,
• FIG. 34 is an axial section through a tool for removing a section of concentric control line, and FIG. 35 is a section through a transverse plane F,
• FIG. 36 illustrates the operation of removing a section of concentric control line,
• finally, FIGS. 37, 38, 39 and 40 illustrate the operations for removing a special valve according to the invention.

To avoid adding to the description, the elements or operations which are already well known to man of the trade will be mentioned but not described in detail; of more, English terminology being most often used in this sector, we gave for some expressions the corresponding English term in quotes in order to facilitate human understanding of the art.

The process illustrated in Figures 1 to 10 is intended to ensure the safety of a well tanker equipped with a classic bottom safety valve whose hydraulic control line has broken down. We have referenced in these figures in 1 the production tube, in 2 the external casing, in 3 the suspension assembly ("spool" or "tubing hanger"), in 4 the original hydraulic line deficient which crosses the assembly 3, passes between the casing external and the production tube and passes through the receptacle sleeve referenced in 5 to lead to the classic valve background referenced in 6, and in 7 the classic system of valves and taps, designated wellhead.

The first operation of the process (Figure 1), well known in itself to professionals, consists in equipping the wellhead 7 with an airlock 8 through which runs the cable of a standard lowering device 9. The tools necessary for operations to be performed.

The original valve 6 is extracted from the well using a traditional fishing tool 10 (figure 2).

The production tube 1 is then released and are installed successively in this one, like the shows diagrammatically in FIG. 3, a downhole plug 11 ("plug"), a classic bottom valve 12 in the closed position in the receptacle sleeve 5 of the original valve (this conventional valve 12 can be the original valve 6 itself after verification or a different valve of the same type) and, on the surface, a non-return valve 13 ("BPV: Back Pressure Valve ") which is hung in the set of suspension 3. These operations and the corresponding tools are classic.

At the end of these operations, the well will found fitted with three safety barriers, plug 11, closed valve 12 and valve 13, so it is possible to disassemble the wellhead 7 respecting the standards of security. Figure 4 shows schematically the well thus freed from surface equipment.

We then set up an element 14 of wellhead riser (Figure 5) which will allow later to subject and feed the news hydraulic control line. This enhancer 14 which will be described in detail below, is fixed on suspension assembly 3 by studs crossing the flange of said assembly (flange conventionally used for fix the wellhead to it).

The wellhead 7 and the airlock 8 are then replaced as shown in Figure 6. The head of well is fixed by studs on the element of extension 14.

With the wellhead back in place, it is possible to remove the non-return valve 13, then extract the classic bottom valve 12 as well as the bottom plug 11, as illustrated in FIG. 7. These operations are conventional and are executed by means of classic tools.

The production tube 1 is then released as shown in figure 8.

The special safety valve (generally referenced at 15 in FIG. 9) can then be placed in the receptacle sleeve 5 which contained the original valve. The special valve, the installation operation of this (which is carried out using the cable lowering device 9) and the installation tool used will be detailed later.

Once the special valve 15 is anchored and locked in the receptacle sleeve 5, it is put in place a hydraulic control line for this valve, called concentric command line (generally referenced in 16 in Figure 10). This line extends inside the production tube 1 along the axis of it and is hydraulically connected to a fluid inlet control 17 through the raising element 14. This line, its installation (which is carried out using the cable lowering device 9) and the tools used will be detailed later.

A classic pressure test is performed on the concentric command line to verify the correct operation of the special valve.

The airlock 8 can then be removed. Well is again in a production situation with a bottom safety valve which guarantees operation according to safety standards.

The special safety valve 15 is shown in detail in Figures 11 to 15.

In Figure 11, the valve is shown in axial cut in closed position in the sleeve receptacle 5 (shown in broken lines). We sees in 5a the passage of fluid from the receptacle sleeve which supplied the original valve, and in 5b the throat anchor with which the receptacle sleeve is fitted, with its lower stop shoulder 5c ("no-go"). In Figure 12, the valve is shown in axial section in position opening, the receptacle sleeve not being drawn.

Said special valve includes a body of valve 18 of generally tubular shape, constituted so classic of several tubular parts subject to to each other; the upper part 18a of the body is fixed on the lower part 18b by screws shear 19 in order to allow, in a manner known in to unlock the valve when it is removed.

Inside the body is mounted a tubular slide 20 able to move longitudinally in the body between a low position (corresponding to the opening of the valve: figure 12) and a high position (corresponding to its closing: figure 11). This slide is called back to its position high by a return spring 21 and is controlled towards the bottom, as we will see, by the pressurization of the concentric command line 16.

In the lower part, the valve body contains a movable shutter member constituted in the example by a valve 22 which is articulated on said body so as to ability to rotate between an open position where it is retracted to the side by the slide 20 (Figure 12) and a closed position where said valve - released by raising of said slide block the valve body in applying against a seal carried by it. The valve 22 is returned to the closed position by a spring arranged around its axis of articulation. he it should be noted that this shutter member, well known in itself, may be of another type and in particular an organ with ball which ensures the obturation by a spherical part able to move longitudinally with rotation associated.

In contrast to this shutter, the body contains a mechanical dog anchoring system which can be of any known type and which is intended, during the placing the valve in the production tube, anchor it in the receptacle sleeve 5. This anchoring system can in particular be of the type of that shown in FIGS. 11 and 12, comprising anchor dogs 23 movable radially to be able penetrate into the anchoring groove 5b of the receptacle sleeve, a dog locking socket 24, mounted sliding in the body and having a cam peripheral 24a adapted to be able to repel radially the dogs, and a return spring 25 urging the locking sleeve 24 upwards. These various organs present, when installing or removing the valve special, a classic operation that is found in most known valves.

Furthermore, the slide 20 defines a sealed volume 29 between its peripheral face and the face valve body internal (whose internal diameter is expanded for this purpose). This sealed volume, filled with oil, is delimited, in the upper part, by a seal 30 located at the interface between body and slide, and partly low, by a gasket 31 of the same diameter as the attached 30.

In the example, the return spring 21 of the slide is disposed in the sealed volume 29, in support, on the one hand, against a stop piece 33 of the valve body, on the other hand, against an annular rib 34 of the slide, which projects into the sealed volume 29. This arrangement protects the spring 21 which is found in oil without contact with effluent.

The valve further includes a piston internal 26 extending along the axis of its body tubular 18. The lower end 32 of the piston is profiled to reduce turbulence at the heart of the effluent called to flow through the valve. This piston 26, of small diameter relative to the internal diameter of the body, bears to its part lower a pusher 27 consisting of a tube section arranged in the valve body so that it can slide in this one. This section of tube is secured to the piston internal 26 by radial arms 28 (in number example of two). This tubular pusher 27 is disposed above and in contact with the slide 20 so as to be able to repel said slide down when moving descending from the internal piston 26. In the absence of effort towards the bottom exerted on the piston, the pusher 27 leaves the slide free to go up under the action of its spring 21 (pushing back said pusher), causing the tilting of the valve 22 and the closing of the valve.

In the upper part, the internal piston 26 slides in an axial sleeve 36 which is secured to the valve body by radial arms 37, in the example in number two. Seals 38 at the interface bush / piston allow telescopic movement tightness of the internal piston in the socket between a high position corresponding to the closing of the valve 22 (figure 11) and a low position corresponding to its opening (figure 12). The upper end of the socket axial is provided with an external thread 35.

At its upper part, a connector male 39 is screwed onto the thread 35 of the axial sleeve 36. This male connector is adapted to cooperate with a conjugate female connector fitted to the control line concentric 16 for locking purposes automatic waterproof at the touch of a button connectors.

Figure 15 shows an example of realization of such a male connector 39. (The connector female conjugate will be presented in detail with reference to the figure 21 during the description of the command line concentric). This male connector includes a body of connector 40 produced in two pieces 40a, 40b, one screwed in the other, with interposition of a joint sealing 40c. The part 40a is itself screwed by its thread 35 on the end of the sleeve 36, however that, in contrast, the part 40b forms an elongated nose 41 intended to penetrate into a conjugate female connector. This nose has anchoring structures 42 in this connector female, in the example an annular rib having a conical access ramp 42a and a stop shoulder 42b. The pieces 40a, 40b forming the connector body are hollow and define a hydraulic passage for the ordered. A valve 43 is disposed in this passage hydraulic to close it when the male connector is not engaged with a female connector. To this end, a spring 44 resiliently biases the valve towards its closed position; the valve 43 is extended by rod 45 housed in the nose 41 in order to repel said flap to the open position when the connector male is connected in the female connector.

Furthermore, the body 18 of the valve special door, on its external face, two sets of seals 46 and 47, in particular of the type with rafters, which are arranged to position on one side and other from the passage of the fluid 5a from the receptacle sleeve when the valve is anchored therein. These toppings isolate the original command line which no longer has any effect.

Of course, the special valve according to the invention includes or may include any other means known valves which are generally provided with bottom safety (in particular profile 48 for attaching the installation and removal tool, which can be seen in the figures 11 and 12 at the top of the valve body).

When the special bottom valve above described is anchored in the receptacle sleeve of the production, its operation is similar to that of a conventional bottom valve, except for the control of the slide down slide 20. When the line concentric control panel 16 is depressurized, the slide 20 is recalled by its spring 21 towards its high position where it is set back from the valve 22 (figure 11): valve 22 is free and closed by its own spring. The valve is blocked and the pressure effluent increases the seal by pressing the valve in his seat. If we pressurize the line of control, the internal piston 26 is actuated down and its tubular pusher 27 causes a movement towards the bottom of slide 20 until it comes into abutment against the nose lower valve (Figure 12): said slide pushes back the shutter valve 22 and keeps it in its position opening. Any drop in pressure on the line concentric control (voluntary or accidental) generates releasing the valve and pivoting it to the position closing.

Figures 16 and 17 show the wellhead riser element 14, which allows to subject and feed the command line concentric down to the special valve along the axis of the production tube.

This enhancement element includes a body 49 called to be fixed on the suspension assembly 3. This body has holes on its lower underside threaded blinds (not visible) for screwing studs through the flange of the suspension assembly. The same fixing means are provided on the upper face of the body 49 for its attachment to the flange of the head well 7.

The body 49 is provided with a central bore diameter at least equal to that of the production tube 1 (preferably equal to the bore of the well head 7) and a lateral channel 50 opening into said bore for the passage of control fluid. This channel is intended to be connected, in a conventional manner, with the inlet duct of the control fluid symbolized in 51.

In addition, the body 49 is provided with means for restraint of the concentric command line (means of suspension of the suspension block which the latter comprises at its high end and which can be seen at 56 in Figure 16). These retaining means include, in the example, screws stop such as screws 52 and screws 53 arranged on two levels in the body. Each level includes at least three screws stop regularly distributed around the body (three screws 120 ° have been shown in Figures 16 and 17). Each screw crosses the body in order to protrude after tightening in the bore thereof by a stop end 52a, 53a; it can be erased by unscrewing. Sealing means such as rafter joints 54 provide watertightness along screws. At the end of tightening, a shoulder 55 achieves a metal / metal sealing.

The two levels of stop screw are offset in height to be able to position themselves below and above the suspension block 56 in order to retain this one, while authorizing its rapid release during removing the command line.

The concentric command line 16 called to hang on the extension element 14 is shown in Figures 18 to 23.

This line consists of a system head shown in axial section in Figure 18, by a upper section shown in axial section in Figure 19 and by common sections as shown in section axial in Figure 20.

The head system includes a block of suspension 56 already mentioned, suitable for accommodating in the raising element 14 in order to be retained by the screws stop 52 and 53 thereof. This block is endowed with its part upper of a hooking profile 57 intended to cooperate with combined means of a fitting or removal tool.

This block is hollowed out with an internal channel blind 58 along its axis and a lateral channel 59 communication this internal channel 58 with the lateral channel 50 of the enhancement element. Two annular seals sealing such as 60 seal between two channels at the block / riser interface.

The suspension block 56 carries a socket 61 which extends downwards and has fins centering such as 62 towards its lower end in order to center said socket in the production tube of the well. In the example, three 120 ° fins are provided around the socket.

The upper section of the line (figure 19) includes a tubular sleeve 63 of diameter adapted to be sliding in the socket 61. Means sealing such as seals 64 provide sealing to the interface between these elements. The length of the sleeve 63 is adjusted according to the height of the well production so that said sleeve, positioned above the common sections (of standardized length), enters the socket 61 at the end of setting up the line.

At its upper end, the sleeve 63 has a male connector 65 identical to that already described for the special valve, to allow installation or removing the upper section.

At its lower end, the sleeve 63 has a female connector 66 identical to those of current sections (described below) in order to be able to connect with the male connector of the current section of the below.

In addition, two centralizers 67 and 68 are sliding friction mounted around the sleeve 63 for center it in the production tube. The centralizer upper 67 will be pushed back by the sleeve 61 during the installation of the line to remain, through the play of friction, below the lower end thereof. The lower centering device 68 is similar to the centering device lower which equips each current section described below, in order to fulfill, in addition to the centering function, an unlocking function of the female connector of the section when removing the line.

Each running section (Figure 20) of standardized length, for example of the order of seven meters, includes an upper male connector 69 (identical to that of the special valve) screwed to the upper end of a hollow connector holder 70. This connector holder 70 is provided with a centralizer 71 mounted at friction around it to be able to slide. This centering device can consist of a tubular element around which are welded three fins at 120 °. of the ring seals such as 72 at the connector holder / centering interface provide friction forces suitable to avoid spontaneous movement of the centering device in the absence of thrust force, while allowing such downward movement when subjected to a force of thrust when removing the section. Structures stop, such as shoulder 73, limit movement up the centering device and define its normal position when the line is in place.

The connector holder 70 is screwed by its lower end in a hydraulic connection tube 74 which gives the section the standardized length desired. This tube 74 is itself screwed in the lower part on a hollow connector holder 75 similar to the previous one; this last door, at its other end, a connector female 76, screwed thereon.

The connector holder 75 has a centering device 77 having fins similar to centering device 71 and mounted frictionally in the same way to be able, in case of pushed down, slide along the connector holder 75 and female connector 76. A shoulder upper 78 of the connector holder defines the position normal work of the centering device, while a shoulder stop 79 limits the downward movement of the centering device and defines a stop position corresponding to the unlocking the female connector 76. Figure 20 shows the centering device in its normal working position (high position). The detail figure 21 shows the centering device in its stop position for which its element tubular produces the unlocking of the female connector by pressing the cam to unlock it.

Figure 22 is a detail axial section of the female connector 76, called to cooperate with the male connector 39 already described. This female connector includes a connector body 80 (made in two parts hollow like the male connector) which is provided with a interior housing for the nose of the male connector. A movable anchor member 81 is disposed in this housing to be able to cooperate with the anchoring structures of the male connector.

This anchoring member 81, movable in the transverse direction, is biased towards its anchoring position by a spring 82 and has an erasing structure such as inclined ramp 81a which allows its erasure under thrust from the nose of the male connector. This can come and get in anchor position by simple pressure, its anchoring structure cooperating with the organ anchor 81 of the female connector; locking is carried out by means of a stop shoulder 81b which comprises the anchoring member.

In addition, the anchor member 81 carries a release cam 83 slightly protruding from outside the body 80 in order to ensure an erasure of the anchoring member and its unlocking under the effect of the pressure of a surface on the cam. So the unlocking can be ensured automatically, when removal, through the cylindrical surface of the centering device 77 of the connector holder when said centralizer reaches its position low.

In addition, the female connector 76 includes a valve 84 for closing its internal passage, associated with a spring 85 which biases it towards the position closing. This valve has a rod 86 which is called to cooperate with the valve stem 45 of the connector male to operate the valve to its position when the male connector is anchored in the female connector. So the connectors when they're are closed tightly and are capable of mechanically lock to each other, automatically, by simple pressure, to create a hydraulic passage continuous and waterproof. Figure 23 shows a connector male and female connector in the connected position.

Figures 24 to 27 illustrate the operation for fitting the special valve according to the invention. This operation is carried out, as already indicated in the general description of the process (Figure 9), using a standard type cable lowering device which is equipped with a fitting tool 87 known per se. This known tool will not be described in detail: it is provided with means for hanging the valve (fingers 88 cooperating with the attachment profile 48 of the valve) and means of maintaining its shutter valve in the open position (tube sector 89 which extends the tool downwards: English "prong"). This tube sector 89 has a section adapted to pass and slide in the space separating the two radial arms 28 of the valve special as shown in figure 26 (section at this level). Similarly in the upper part, the tubular part 90 of the tool ("probe"), which is called upon to move the socket 24 from the valve down during installation in order to release the anchor dogs 23, is shaped into two tube sectors 90a, 90b, to allow passage through the arms radials 37 of the special valve, as shown in the figure 27 (cut at this level). Except for these adaptations, the pose 87 is a classic tool, especially with a shear pin (not visible) which is broken when of the pose.

The valve installation operation is carried out according to a known procedure: the tool is hung on the valve, then introduced into airlock 8 and lowered into the well. When the valve is in place in its receptacle sleeve 5 (valve placed on the "no-go" 5c of the receptacle sleeve, anchor dogs 23 located opposite the groove for anchoring said receptacle sleeve: FIG. 24), a hammering down the tool is operated to break the shear pin of it. Ways of the tool is released from the attachment profile of the valve, and the tool is released and can be reassembled (figure 25). Part 90 ("probe") releases socket 24 which goes up under the action of its spring and locks the anchor dogs 23 in the anchoring groove 5b of the receptacle sleeve. In addition, sector 89 ("prong") releases the shutter valve 22 which closes under the action of its spring.

Once the special valve is in place in the production tube, we install the concentric control which ensures the maneuvers hydraulics thereof. The tools for installing it and the laying operations are illustrated in Figures 28 to 33 (operations shown globally in Figure 10, already commented in the general description of the process).

The installation tool shown in Figures 28 and 29 is called upon to equip the descent device to standard cable for laying a current section of line or the upper section. This tool which is shown in figure 28 in armed position, ready to enter a section, includes a hooking head 91 provided with a profile adapted for its attachment to the descent device, a mandrel 92 carrying in the lower part a female connector 93 of the type already described, and an unlocking sleeve 94 which is screwed into the head 91 and which carries the mandrel 92 by through a shear pin 95.

As illustrated in Figure 29, the pin 95 shear allows the sleeve to unlocking 94 to move down from the mandrel 92: the tubular lower part 94a of this sleeve which is arranged around the female connector 93 then ensures the unlocking of this connector by pressing on its unlocking cam 83.

Figure 30 shows the descent of a current section of line in the production tube at using the aforementioned tool, the section having been, on the surface, hooked and locked by its male connector to tool female connector.

The descent continues until reaching hooking and locking the female connector located at the bottom of the section with the male connector of the lower section already in place (or with the male connector the special valve in the case of the installation of the first section of line). A hype down the installation tool is then produced to generate a shear of its safety pin (figure 31).

The female connector of the tool is unlocked by the descent of the sleeve 94 and the connector male from the line section is released. The tool can be reassembled (Figure 32) and reset using a new shear pin for placement of the next stretch. This rearming, carried out on the surface, is operated after partially unscrewing the sleeve 94 by relative to the head 91 in order to release the pin hole.

Figure 33 illustrates the installation of the command line head system, with a tool classic 96 which is attached to the attachment profile of the suspension block 56 of said system. The set is lowered to the cable until the socket 61 of the system engages around the tubular sleeve 63 of the section block and that block 56 comes into abutment with the screws lower stop 52 (previously projecting internal position). Stop screws upper 53 can be screwed to block the block suspension, and the setting tool can be released and reassembled in a classic way.

When the concentric command line is installed, a pressure test is performed to check the correct operation of the special valve, and the airlock can be dismantled on the well head. The well is found put in safety.

To remove the special valve in case of need, first carry out the removal of the line of concentric control: the head system of this line is removed by unscrewing the stop screws and reassembled cable, then the line sections are removed, section after section.

Figures 34 and 35 show the tool which is to equip the cable device standard for depositing each section of line.

This tool includes a hooking head 97 to the lowering device, a female connector 98 of the type mentioned above, secured under the hanging head 97, and a push tube 99 secured to said head 97 and passing around the female connector 98 with a light 99a at the level of the unlocking cam of this connector so to leave it free.

The push tube 99 extends downward on a suitable length to be able to slide around a section of line and push back the centralizers of it up to the level of the connector release cam female of said section. Towards its lower end, the push tube 99 has centering fins 100, in the example three in number at 120 °, in order to center the push tube in the production tube when it is descended into this one.

Figure 36 illustrates the removal operation a section of line using the tool defined above. The tool is lowered to the cable until its push tube 99 starts around the line section. The descent is continued and the push-tube 99 pushes back downwards the centralizers 71 and 77 of the line section. The lower centering device 77 reaches its position of unlocking in which it clears the cam unlocking the female connector 76 of the section: this female connector is released from the male connector of the section lower line (or special valve for the last section), however in the upper part, the connector tool female 98 locks onto the male connector 69 located at the upper end of the line section.

The removal tool can then be reassembled with the line section hooked under its connector female 98. On the surface, the line section is released and removed by pressing the cam of said female connector to through light 99a. The removal tool is then ready to extract another section of line.

Finally, Figures 36 to 39 illustrate the removing the special valve, once its line has been removed concentric command as just described. This removal is carried out in a conventional manner using a recovery 101 fitted to the cable lowering device standard.

This drafting tool has fingers hook 102 coming to cooperate with the profile hooking 48 of the valve. When the snap is realized (figure 36), a threshing upwards by percussion is used to break the screws shear 19 of the special valve: the upper part 18a valve body is moved up (Figure 37) and causes the socket 24 for locking dogs which are released (Figure 38). The valve can then be reassembled, its socket 24 driving the lower part 18b of the body valve.

Claims (11)

1. Method for restoration to safety of an oil well, of the type comprising a production pipe (1), a base safety valve, known as an original valve (6), inserted in a sleeve-receptacle (5) which is accommodated in the production pipe, and a hydraulic control line for the said valve, the said original control line (4) comprising a line for supply of pressurised fluid situated outside the production pipe and a fluid intake which is provided through the sleeve-receptacle in order to open out at its periphery from the valve, the said method being designed to assure restoration to safety of the well in the event of a defect in the original control line, and being characterised in that the original valve (6) is replaced by a special base valve (15) comprising along its axis and in its upper part, means (39) for hydraulic connection, at its periphery, means for isolation of the original control line or for shutting the latter in a sealed manner, and in the lower part, a mobile shutter unit (22) which can be manoeuvred at closure by the action of a pressurised fluid which is admitted axially via the hydraulic means for connection, a new hydraulic control line is installed inside the production pipe (1), along the axis of the latter, which line is known as the concentric control line (16), and the said concentric control line is connected to the means for hydraulic connection of the special valve.
2. Method according to claim 1, for restoration to safety of an oil well which is provided in its upper part with a valve and tap system, known as the wellhead (7), the said method being characterised in that the original valve is replaced by a special base valve (15) comprising a valve body (18) with a generally tubular shape, a mobile shutter unit (22) which is situated in the lower part of the said body and is thrust towards its position of closure, a tubular slide (20) which is designed to be able to slide longitudinally inside the valve body such as to give rise in its descending motion to opening of the shutter unit, resilient return means (21) which are designed to thrust the said slide towards an upper position corresponding to closure of the shutter unit, an anchorage system (23-24-25) which is situated in the upper part of the valve body and is designed to secure the latter in a sleeve-receptacle accommodated in the production pipe, an inner piston (26) which extends along the axis of the valve body (18), a thruster (27) which is supported by the lower part of the inner piston (26) and is disposed in the valve body above and in contact with the slide (20) such as to be able to thrust the said slide back downwards during descending displacement of the inner piston, an axial bush (36) which is integral with the valve body and is disposed along the axis of the latter in order to receive in a sliding manner the upper part of the inner piston, means (38) for sealing between the inner piston (26) and the axial bush (36), means (39) for hydraulic connection of the upper end of the bush (36) to a hydraulic control line which extends inside the production pipe, at least two sets of packing (46, 47) disposed on the outer surface of the valve body and offset along the height of the latter such as to assure isolation of the original hydraulic control line of the production pipe, the method for replacement of the valve and installation of the concentric control line comprising the following successive operations:

   (a) fitting of a chamber (8) onto the wellhead (7);

   (b) extraction of the original valve (6) in order to release the production pipe (1);

   (c) putting a stopper (11) into place at the base of the well;

   (d) putting a conventional safety valve (12) into place in a closed position in the sleeve-receptacle (5) of the production pipe;

   (e) fitting of a non-return valve (13) above the production pipe (1);

   (f) removal of the wellhead (7) and of the chamber (8);

   (g) putting into place above the non-return valve, a wellhead-raising element (14) comprising in standby means (53, 54) for securing the concentric control line and means (50) for passage of the fluid towards the said line;

   (h) putting the wellhead (7) and the chamber (8) back into place;

   (i) depositing of the non-return valve (13);

   (j) extraction of the conventional safety valve (12) and of the stopper (11) at the base of the well in order to release the production pipe;

   (k) putting the special base valve (15) into place;

   (l) putting the concentric control line (16) of the said special valve into place;

   (m) pressure test on the concentric control line in order to check the opening of the special valve; and

   (n) removal of the chamber (8) from the wellhead.
3. Special base valve for restoration to safety of an oil well equipped with a production pipe, comprising:

   a valve body (18) with a generally tubular shape;

   a mobile shutter unit (22) which is situated in the lower part of the said body and is thrust towards its position of closure;

   a tubular slide (20) which is designed to be able to slide longitudinally inside the valve body in order to give rise in its descending movement to opening of the shutter unit;

   resilient return means (21) which are designed to thrust the said slide towards an upper position corresponding to closure of the shutter unit;

   an anchorage system (23-24-25) which is situated in the upper part of the valve body and is designed to secure the latter in a sleeve-receptacle accommodated in the production pipe;

   means (46, 47) for sealing which are disposed on the outer surface of the valve body such as to assure isolation of the original hydraulic control line from the production pipe;

   the said special valve being characterised in that it comprises:

   an inner piston (26) which extends along the axis of the valve body (18);

   a thruster (27) which is supported by the lower part of the inner piston (26) and is disposed in the valve body above and in contact with the slide (20) such as to be able to thrust the said slide downwards during descending displacement of the inner piston;

   an axial bush (36) which is integral with the valve body and is disposed along the axis of the latter in order to receive the upper part of the inner piston in a sliding manner;

   means (38) for sealing between the inner piston (26) and the axial bush (36); and

   means (39) for hydraulic connection of the upper end of the bush (36) to a hydraulic control line which extends inside the production pipe.
4. Special valve for restoration to safety according to claim 3, characterised in that the thruster consists of a section of pipe which slides in the valve body and is supported by the inner piston (26) by means of radial arms (28) which make it integral with the latter.
5. Special valve according to claim 4, wherein the resilient return means for the slide comprise a return spring (21) which is disposed in a sealed volume (29) situated between the slide and the valve body, characterised in that the slide (20) is provided with an annular rib (34) which projects in the said sealed volume (29) in order to act as a support for an end of the return spring (21) of the slide, the other end of the spring being supported against a stop (33) which is integral with the valve body.
6. Special valve according to any one of claims 1 to 5, characterised in that the axial bush (36) is rendered integral with the valve body (18) by means of radial arms (37).
7. Special valve according to any one of claims 1 to 6, characterised in that the means for hydraulic connection comprise a male connector (39) which is fitted at the head of the axial bush (36) and is designed to co-operate with a female connector which is connected integrally to the hydraulic control line.
8. Special valve according to claim 7, characterised in that the aforementioned male connector (39) comprises a connector body (40) which is provided with a nose (41) for penetration into the female connector of the hydraulic control line and contains longitudinally a hydraulic passage, structures (42) for anchorage of the connector nose in the female connector, a flap valve (43) for closure of the hydraulic passage, resilient means (44) which thrust the flap valve towards its position of closure, and a flap valve rod (45) which is accommodated in the nose of the connector in order to thrust the flap valve towards the position of opening when the male connector is connected in the female connector.
9. Special valve according to any one of claims 1 to 8, wherein the anchorage system is a mechanical system comprising anchorage pawls (23) which are mobile radially in order to be able to penetrate in an anchorage groove in the sleeve-receptacle, a bush (24) for locking the pawls which is fitted such as to slide in the valve body and has a peripheral cam (24a) which is designed to be able to thrust the pawls back radially, and a return spring (25) which thrusts the locking bush upwards.
10. Method for restoration to safety according to claim 2, wherein (k) the special valve (15) is put into place by means of a cable descent device (9) of a standard type, equipped with a conventional fitting tool (87) provided with means (88) for capturing the said valve and means (89) for retention of its shutter unit in the open position.
11. Method for restoration to safety of an oil well according to claim 1 or claim 2, characterised in that (l) there is put into place according to the axis of the production pipe a hydraulic control line comprising a plurality of sections which are designed to be disposed end to end by means of a cable descent device of a standard type which is equipped with a fitting tool, the said putting into place being carried out section after section, by implementing the following operative procedure for each section:

    capture and locking of the male connector contained on the section of line, to the female connector (93) contained on the fitting tool;

    descent by cable of the assembly in the production pipe of the well, until capture and locking takes place of the female connector contained on the section, to the male connector of the lower section which is already in place, or to the male connector of the special valve for the first section which is put into place;

    driving downwards of the fitting tool until shearing takes place of the pin (95) contained on the fitting tool, giving rise to release of the female connector (93) from the fitting tool and detachment of the male connector from the section of line; and

    raising of the fitting tool and re-arming by means of a new pin in order to put the following section into place.

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