RU2542005C1 - Coiled tubing preventer - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: preventer comprises a body with vertical feedthrough hole for pipes, two horizontal cavities with shear blinded rams and pipe hold-down rams placed symmetrically in regard to the vertical feedthrough hole, hydraulic drives for rams movement, channels feeding pressurised ram control fluid, reverse valves, manual drives for rams and kinematic connection units connecting manual drives with hydraulic drives for rams.

EFFECT: increased reliability and safety of preventer operation.

10 dwg

Description

The invention relates to equipment for sealing the mouth of oil and gas wells during the descent and lifting of long clutchless (coiled tubing) pipes during construction, development, research and repair of wells in order to ensure safety, prevention and elimination of oil and gas manifestations, protection of the subsoil and the environment.

The well-known "Preventor" (Patent PM No. 48354, E21B 33/06, published 10.10.2005, bull. No. 28), containing:

- a housing with a vertical passage hole for pipe passage and four horizontal cavities symmetrically located relative to the vertical passage hole one above the other,

- in which pipe, holding, detachable and blind dies are mounted with the possibility of movement,

- hydraulic drives for moving dies,

- channels made in the housing and hydraulic actuators for supplying pressure control dice under pressure,

- check valves, preventing the drainage of fluid from the channels during the dismantling of hydraulic actuators, containing interacting valves, controlled by elastic elements,

- manual drives for blind and tube dies, containing pushers with helms,

- and the nodes of the kinematic connection of manual drives with hydraulic actuators for blind and pipe dies.

A disadvantage of the known preventer is its significant height dimension, due to the need to place several types of dies in the housing to provide enhanced operational capabilities of the preventer, which requires increased labor costs for its maintenance, as well as during the installation of equipment installed on the upper flange of the known preventer.

In addition, the well-known preventer after capturing a deflated pipe and cutting it in case of failure of the hydraulic drive, it is impossible to open the cutting and holding dies, since the manual drive is intended only for closing and fixing them. This reduces the reliability of the use of the known preventer, since the time required to restore the hydraulic drive can be significant, and the inability to walk down pipes in the well can lead to their seizure with unavoidable time to eliminate emergency consequences.

The design of the check valves of the known preventer involves the interaction of the valves when they move from the seat with the squeezing of the elastic elements and the formation of annular gaps for fluid flow. Moreover, after opening, the position of the valves relative to the seats is not fixed and depends on the effort of the elastic elements. In this regard, the displacement of the gates can be different, for example, due to unequal in the magnitude of the efforts of the elastic elements or errors in their manufacture, even within the tolerances. This will lead to the fact that the area of annular gaps for fluid flow at different gates may be different, which is a disadvantage of the known preventer, since due to the unfixed position of the gates and the likelihood of reducing the annular cross-sectional area around one of the gates, a situation may arise in which circulating liquid , overcoming the resistance of the elastic element, it will move the shutter to its seat and block the hydraulic control channel. In this case, the preventer becomes uncontrollable from the hydraulic actuator and in case of an emergency will not be able to provide operational sealing of the wellhead, since the transition to manual control due to the design features of the known preventer requires a significant investment of time.

The latter is explained by the fact that for manual closing of the dies, it is necessary to first unlock the movable bracket, move it until the holes of a smaller diameter are combined with the annular groove of the pusher and fix in this position. This will ensure the motion of the pusher in the longitudinal direction and the kinematic interaction of the screw pair of the pusher and the shaft to return the dies. Then, by rotating the pusher, unscrewing it from the shaft, the latter is moved together with the piston and ram to close the preventer. A similar procedure must be performed for the manual opening of the dies in the event of a hydraulic drive failure.

Such a significant investment of time at first trying to close the preventer from the hydraulic control panel, and then to identify the failure of the latter and switching to manual drive does not ensure the efficiency, reliability and safety of work to prevent or eliminate oil and gas manifestations, as a result of which an open gas and oil fountain may arise, the elimination of which require significant costs.

The combination of these circumstances reduces the reliability and ease of maintenance of a well-known preventer.

The well-known "Preventor" (Patent PM No. 51659, ЕВВ 33/06, published February 27, 2006), containing:

- a housing with a vertical passage hole for pipe passage and two horizontal cavities symmetrically located relative to the vertical passage hole one above the other,

- in which shear blind and retaining tube dies equipped with semi-ring seals are installed with the possibility of movement,

- moreover, one of the shear deaf and holding pipe dies are equipped with U-shaped seals,

- hydraulic drives for moving dies,

- channels made in the housing and hydraulic actuators for supplying pressure control dice under pressure,

- check valves, preventing the drainage of fluid from the channels during the dismantling of hydraulic actuators, containing interacting valves, controlled by elastic elements,

- manual dice drives containing pushers with helms,

- and the nodes of the kinematic connection of manual drives with hydraulic dies.

The known preventer is equipped with hydraulic actuators with manual actuators, a kinematic connection between them and valves for blocking the channels, identical in design to the analogue, and therefore has similar disadvantages.

In addition, the known preventer is characterized by low reliability during operation, due to a possible loss of tightness between shear blind dies after cutting the pipe and blocking the wellhead. This is due to the features of the preventer, its design, the relative position of the nodes and parts and is as follows:

- after cutting a long pipe, the edges of its end face due to deformation and stretching of the metal have a torn uneven surface with varying degrees of approximation of the formed edges to the cutting die. As a result, the sealing protrusion of the jumper of the U-shaped part of the seal of the die, moving directly above the surface of the edges of the end face of the cut pipe, can be deformed by them until it breaks and will not ensure the tightness of the overlap of the vertical passage after closing the dies;

- a prerequisite for sealing the wellhead known preventer is the coaxial arrangement of shear blind dies when they are closed. At the same time, closed dies must be pressed against the seat of the upper part of the housing chamber to ensure tightness. However, the vertical passage hole made in the preventer housing does not provide the necessary support for closed dies, and therefore, with increasing borehole pressure, the upper part of the closed ends of the dies can be forced upward into the vertical passage hole, which will lead to misalignment of the relative position of the dies. In this case, the sealing protrusion of the U-shaped seal jumper will depart from the seat, as a result of which the joint will be depressurized;

- the prefabricated design of the seal dies does not provide reliable sealing, since at the junction of the semicircular and U-shaped seals there are joints in which gaps are possible.

The low reliability of the known preventer may also be due to the possibility of falling into the wellbore of a knife located in the lower position after cutting the pipe. This is due to the fact that this knife, interacting with the end face of the cut pipe, can be clamped with a force exceeding the force of holding the knife in the die. Therefore, when the preventer is opened and the die is moved, the knife clamped by the force of interaction with the end face of the cut pipe will remain stationary, which will lead to its disengagement from the die, and therefore the knife may fall into the well, creating an emergency.

The combination of these circumstances significantly reduces the reliability and safety of the well-known preventer.

The objective of the invention is to provide a technical solution to the preventer, providing increased reliability and safety.

To ensure this technical result in a known preventer containing:

- a housing with a vertical passage hole for pipe passage and two horizontal cavities symmetrically located relative to the vertical passage hole one above the other,

- in which shear blind dies equipped with half-ring and U-shaped seals and pipe holding dies are installed with the possibility of movement

- hydraulic actuators moving dies containing hydraulic cylinders with pistons and rods,

- channels made in the housing and hydraulic actuators for supplying pressure control dice under pressure,

- check valves, preventing the drainage of fluid from the channels during the dismantling of hydraulic actuators, containing interacting valves, controlled by elastic elements,

- manual dice drives containing pushers with helms,

- and the nodes of the kinematic connection of manual drives with hydraulic dies,

according to the invention:

- housing shear blind dies equipped with a triangular protrusion and a triangular reciprocal groove, seamlessly interacting with each other when closing the preventer,

- detachable knives are installed in grooves made on a triangular protrusion and a triangular reciprocal groove of the shear blind dies bodies, and are fixed with a key,

- interacting sealing surfaces of the seals are located on the triangular surfaces of the protrusion and the reciprocal groove of the shear blind dies bodies,

- semicircular and U-shaped seals are made in the form of a single integral element without a connecting surface,

- between the ball valves of the check valves installed spacers with slotted channels,

- the kinematic connection unit of the manual drive with a hydraulic actuator is made in the form of a threaded rod passing through a through hole made in the pusher connected to a threaded hole made in the rod and fixed with a pusher with a locking finger.

The invention is illustrated by drawings, which depict:

figure 1 is a longitudinal section of a preventer, the dies are opened by a hydraulic actuator;

figure 2 is a longitudinal section of a preventer, the dies are closed by a hydraulic actuator;

figure 3 - callout And figure 1, the dies are open;

figure 4 - callout B from figure 2, the dies are opened by a manual drive;

figure 5 - callout In figure 1, the valves are open;

figure 6 - callout In figure 1, the valves are closed;

Fig.7 is a view of G from Fig.6 on spacer sleeves;

in Fig.8 is a view of D on the die 4 of Fig.3;

figure 9 is a view of E on the die 5 of figure 3;

figure 10 - seal 14 with a U-shaped jumper.

The preventer comprises a housing 1 (FIGS. 1, 2, 3) with the possibility of skipping the pipe 2, pipe holding dies 3, blank cutting dies 4 and 5, and hydraulic dies 6.

Cutting die 4 consists of a die body 7 with a triangular protrusion 8, a seal 9 and a cutting knife 10. A cutting knife 10 is fixed in the die body 7 by means of a key 11, for example, of circular cross section.

Cutting die 5 consists of a die body 12 with a triangular groove 13, a reciprocal protrusion 8 of the die 4, a seal 14 and a cutting knife 15. The cutting knife 15 is fixed in the housing 12 of the die 5 by means of a key 16, for example, of circular cross section.

The hydraulic actuators 6 of the dies consist of hydraulic cylinders 17 (FIGS. 1, 2) with pistons 18, rods 19 having threaded holes 20, covers 21 and manual drives 22 (in FIG. 4), including those made in conjunction with the covers 21 of the housing 23, and pushers 24. In each pusher 24, a through hole 25 is made, in which a threaded rod 26 with a hexagonal head and a support 27 mounted on it with a hole 28 and a sliding bearing 29 can be fixed with the locking finger 30 for holes 31 and 32. On the pushers 24 helms 33 installed, instead of which he could The cardan shafts of the manual remote control (not shown) must be connected.

To supply hydraulic fluid through the nozzle 34 (Fig. 1, 5, 6, 7) to the corresponding working cavities of the hydraulic cylinders 17 in the housing 1 and the hydraulic cylinders 17, channels 35 and 36 are made with valves 37 located therein, consisting of ball valves 38 located in holes 39, and springs 40. Between the ball valves 38 spacer sleeve 41 is installed with a slotted channel 42.

On the triangular surfaces of the protrusion 8 and the response groove 13 of the housings 7 and 12 of the shear blind dies 4 and 5, there are interacting sealing sealing inclined surfaces 43 of the seals 9 and 14 and the supporting surfaces 44 (FIGS. 3, 8, 9).

The sealant 14 (figure 10) consists of a semi-ring 45 and a U-shaped 46 jumpers made as a single unit.

The design of the preventer provides and does not show the fixation of the dies 3, 4, 5 and hydraulic actuators 6 from rotation.

The inventive preventer coiled tubing works as follows.

The preventer is installed at the wellhead (not shown), its operation in hydraulic control mode is as follows.

Technological equipment is lowered through the preventer body on a flexible (long) pipe 2 (Fig. 1). In the event of an emergency for sealing the wellhead by the inventive preventer, first into the corresponding cavities of the hydraulic cylinders 17 controlling the pipe holding dies 3, through fittings 34, channels 35, openings 39, in which the ball valves 38, annular gaps around the ball valves 38, slotted channels 42 in spacer sleeves 41 and channels 36, hydraulic fluid is supplied from a power station (not shown). In this case, the spacer sleeves 41 (Fig. 5), located between the ball valves 38, do not allow them to move to the seats and block the channels 35 and 36. The dies 3 under the action of the pistons 18 and the rods 19 are moved before interacting with the deflated pipe 2, capture and seal its outer surface (figure 2).

Then, in the corresponding cavity of the hydraulic cylinders 17 controlling the blind cutting die 4 and the blind cutting die 5, hydraulic fluid from the hydraulic station is likewise supplied. Dies 4 and 5 under the action of the pistons 18 and rods 19 are moved to mutual contact and after cutting the deflated pipe 2 with knives 10 and 15, seal the bore of the housing 1 with seals 9 and 14. When cutting the flexible pipe 2, the working sealing surfaces 43 of the seals 9 and 14 are located above the location area of the cut surface, which ensures the safety of the seals 9 and 14 and the reliability of the seal. The sealant 14 (figure 10), made in the form of a single integral element of the semicircular 45 and U-shaped 46 jumpers, does not have a connecting surface, which also provides reliable sealing. The triangular protrusion 8 of the housing 7 of the die 4 (FIG. 2), which enters the triangular mating groove 13 of the housing 12 of the die 5 and interacts with its surfaces, creates a "lock" that provides coaxial fixation of the cases 7 and 12 of the dies 4 and 5 relative to each other and prevents the depressurization of seals 9 and 14 at the contact point with increasing well pressure, thereby providing reliable sealing.

After the preventer is closed by hydraulic actuators 6, the dies 3, 4 and 5 are fixed in the closed position by manual actuators 22 (Figs. 2, 4), for which the rotation of the handwheels 33 pushers 24 are moved to contact with the ends of the rods 19. In this position, even if the hydraulic actuators 6 fail, thanks to the manual drives 22, the dies 3, 4 and 5 will be closed, providing a sealing of the wellhead, which prevents the occurrence of an open fountain and increases the safety of work in the well.

To open the preventer with hydraulic actuators 6, it is necessary to first unlock the dies 3, 4 and 5 with manual actuators 22, for which the pushers 24 move the pushers 24 from the ends of the rods 19 to the extreme extended positions and then supply hydraulic fluid through the nozzle 34 to the opening cavities of the hydraulic cylinders 17 (Fig. .one).

When working in manual control mode, to close the preventer, turn the helms 33 clockwise. In this case, the pushers 24, interacting with the threads of the housings 23, will move the rods 19 and dies 3, 4 and 5 to their extreme forward positions, and the hydraulic fluid will be displaced by the pistons 18 from the cavities of the hydraulic cylinders 17 into the hydraulic tank.

To open the preventer in manual control mode, it is necessary to first remove the locking fingers 30 (in Fig. 4) from the holes 28 and 31, screw the threaded rods 26 into the threaded holes 20 of the rods 19 until the holes 28 in the supports 27 and the holes 32 in the threaded rods 26 are aligned, install the locking fingers 30 into the holes 28 and 32. Then, when the steering wheels 33 rotate counterclockwise, the pushers 24, interacting with the threaded surfaces of the housings 23, will move outward and pull the rods 19 with dies 3, 4, 5 with threaded rods 26. I-sliding in the form of bearings 27 and sliding bearings 29 will prevent the rotation of the threaded rods 26. The hydraulic fluid is displaced by the pistons 18 from the cavities of the hydraulic cylinders 17 into the tank of the hydraulic station.

For manual remote control of the preventer, propeller shafts (not shown) are attached to the pushers 24 instead of the steering wheels 33, the ends of which, equipped with steering wheels, are placed behind the shelter at a certain distance from the wellhead on which the preventer is mounted to comply with safety rules when operating the preventer. If necessary, the manual drives 22 of the closed hydraulic actuators 6 of the preventer need to be fixed, the helms 33 with cardan shafts are rotated clockwise, moving the pushers 24, which interact with the ends of the rods 19 (Fig. 2), fixing the dies 3, 4 and 5 in the closed position. At the same time, there is no need for service personnel to approach a well under pressure for any manipulations with a hydraulic or manual drive, which increases the safety of operations during operation of the inventive preventer.

If necessary, dismantle the hydraulic actuators 6 from the preventer housing 1, for example, to install pipe retaining dies 3 for a pipe of a different size or replace the gaskets 9 and 14, the channels 35 in the hydraulic actuators 6 (Fig. 6) and the channels 36 in the housing 1 are blocked by ball valves 38 moving under the action of springs 40 on the seat, to prevent leakage of hydraulic fluid.

The combination of the above circumstances provides an increase in the reliability and safety of the inventive preventer in comparison with the analogue and prototype.

Claims (1)

A coiled tubing preventer, comprising a housing with a vertical passage hole for pipe passage and symmetrically arranged relative to the vertical passage hole one above the other, two horizontal cavities in which shear blind dies equipped with half-ring and U-shaped seals, and tube retaining dies, hydraulic drives are mounted moving dies containing hydraulic cylinders with pistons and rods, channels made in the housing and hydraulic actuators for supplying liquid under pressure board dies, check valves, preventing the drainage of fluid from the channels during the dismantling of hydraulic actuators, containing interacting valves, controlled by elastic elements, manual die drives containing pushers with helms, and kinematic communication units of manual drives with hydraulic drives of dies, characterized in that shear cases deaf dies are equipped with a triangular protrusion and a triangular reciprocal groove, gaplessly interacting with each other when closing the preventer, cutting knives are installed in the grooves, sheared on a triangular protrusion and a triangular reciprocal groove of the shear blank dies bodies, and fixed with a key, the sealing surfaces of the seals interacting with each other are located on the triangular surfaces of the protrusion and the reciprocal groove of the shear blank dies, the semicircular and U-shaped seals are made in the form of one integral element without a joint surfaces, between spherical locks of the backpressure valves spacers with slotted channels are installed, the kinematic connection unit of the manual drive with dropper is made in the form of a threaded rod passing through a through hole made in the pusher connected to a threaded hole made in the rod and fixed with a pusher with a locking finger.

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