RU2366798C1 - Hydraulic packer - Google Patents

Abstract

FIELD: oil and gas production.

SUBSTANCE: hydraulic packer consists of a hollow mandrel, whereon there are secured an anchor with bowl slip sockets, spring-loaded in radial direction, and a shell forming circular cavity with external surface of the stem; the packer also consists of a sealing component, of a bushing-pusher with radial slots and a radial opening communicating with circular cavity, of cams installed in radial slots of the bushing-pusher, fixing it on the stem and designed to perform axial displacements, of a piston connected to the bushing-pusher with shear screws. A cone is rigidly connected with the piston, a ram holder with radial slots is secured on the stem with shear screws, screw-thread dies with end collars, arranged in radial slots of the ram holder, are assembled on the stem. There is a cylinder fastened on the bushing-pusher and a ratchet assembled on the cylinder for fixing the cylinder relative to the piston. According to the invention the packer is equipped with upper and lower stay nuts with internal circular lug; the nuts are correspondingly secured on the anchor and on the bushing-pusher, with a stop ring installed on the shell and designed to interact with the circular lug of the lower stay nut; also the shell has an external circular lug installed in the anchor, designed to perform axial displacements and to interact with the circular lug of the upper stay nut; while the sealing component is located on the shell between the upper and lower stay nuts.

EFFECT: increased reliability of packer operation.

2 cl, 2 dwg

Description

The invention relates to the oil and gas industry, in particular to packing devices for separating space in production casing during temporary shutdown of formations, installation of removable bridge plugs and other technological operations during the operation and repair of oil wells.

Known hydraulic packer, including a hollow barrel with an annular groove and a number of radial holes, a sealing element, a push rod with radial grooves and cams in them, fixing it on the barrel with the possibility of interaction with the sealing element, a cone mounted on the barrel and connected to the sleeve pusher with shear screws, cylinder, ram holder with dies, fixed on the barrel with shear screws, ratchet connected to the cylinder to fix the push rod with respect to the cone, snap ring, installation flax on the barrel with the possibility of interaction with the sleeve-pusher. [Patent of the Russian Federation No. 2068074, ЕВВ 33/12, 1994].

The disadvantage of the packer is that its design does not have an anchor that keeps the packer from moving upward due to the pressure drop from below, which significantly reduces the reliability of the packer when disconnecting the downhole space without the presence of a tubing string. In addition, the placement of the retaining ring on the bore reduces its cross-sectional area and strength and can lead to rupture of the bore from axial loads arising from the packer removal, especially after its long-term operation in the well.

The closest analogue of the invention is a hydraulic packer, comprising a hollow barrel with an annular groove and a number of radial holes, an anchor mounted on the barrel with radially spring-loaded slips and a shell, forming an annular cavity with the outer surface of the barrel, a sealing element located on the shell, and a pusher sleeve with radial grooves and a radial hole communicating with the annular cavity, cams mounted in radial grooves of the push rod and fixing it on the barrel with axial displacement, a cylinder mounted on the pushing sleeve, a piston connected to the pusher sleeve with shear screws, a cone rigidly connected to the piston, a ram holder with radial grooves, mounted on the barrel with shear screws, rams with end shoulders placed in the radial grooves of the ram holder , ratchet installed in the cylinder to fix its position relative to the piston [Patent of the Russian Federation No. 2194148, ЕВВ 33/12, 2002].

The disadvantage of the packer design is that the shell is rigidly fixed to the armature body. This creates additional axial load on the tubing string when removing the packer, which occurs during friction of the shell and the sealed sealing element and acts simultaneously with the load when cutting the ram holder screws. In addition, the packer barrel is made of three parts connected by a thread, which reduces the strength characteristics and sealing properties of the barrel and can cause complications during installation, operation and removal of the packer. All this reduces the reliability of the packer and can lead to an increase in the cost of repairing the well and ultimately to a decrease in oil production

The technical result of the invention is to increase the reliability of the packer during operation and repair of wells.

The required technical result is achieved by the fact that the hydraulic packer includes a hollow barrel with an annular groove and a number of radial holes, an anchor mounted on the barrel with radially spring loaded slips and a shell, forming an annular cavity with the outer surface of the barrel, a sealing element located on the shell, the sleeve a pusher with radial grooves and a radial hole communicating with the annular cavity, cams mounted in the radial grooves of the pusher sleeve and fixing it on the barrel with the possibility of axial movement, a cylinder mounted on the pusher sleeve, a piston connected to the pusher sleeve by shear screws, a cone rigidly connected to the piston, a ram holder with radial grooves mounted on the barrel by shear screws, rams with end shoulders placed in the radial grooves of the ram holder , a ratchet installed in the cylinder to fix its position relative to the piston, according to the invention it is equipped with upper and lower thrust nuts with an inner annular protrusion, fixed accordingly at the anchor and on the push sleeve, a retaining ring mounted on the shell with the possibility of interaction with the annular protrusion of the lower thrust nut, while the shell is made with an external annular protrusion mounted in the anchor with the possibility of axial movement and interaction with the annular protrusion of the upper thrust nut, and the sealing element is located on the shell between the upper and lower thrust nuts. To exclude the possibility of dies being pulled out of the grooves of the ram holder when the packer is removed, the end shoulders of the rams can be L-shaped, resting their upper part on the ram housing.

In Fig.1 shows a hydraulic packer in its original position, in Fig.2 - node A (embodiment).

The hydraulic packer (Fig. 1) consists of a hollow barrel 1 with an annular groove 2 and a row of radial holes 3, anchors 4 with radially spring-loaded slips 5 and axially mounted shell 6 with an outer annular protrusion 7 forming with the outer surface of the barrel the annular cavity 8, the upper thrust nut 9 with the inner annular protrusion 10, covering the annular protrusion 7 of the shell 6, the sealing element 11, the push sleeve 12 with radial grooves 13 and a radial hole 14 in communication with the front cavity 8, the cams 15, placed in the grooves 13 and temporarily holding the pusher sleeve 12 from axial movements, the lower thrust nut 16 with the inner annular protrusion 17, the retaining ring 18, mounted on the shell 6 with the possibility of interaction with the inner annular protrusion 17 of the thrust nut 16, a cylinder 19, mounted on a pushrod sleeve 12, a piston 20, located between the barrel 1 and the cylinder 19 and connected to the pusher sleeve 12 with shear screws 21, a cone 22, a ram holder 23 with radial grooves 24, mounted on the barrel 1 screws 25. On the barrel 1 with the possibility of interaction with the cone 22 installed radially spring-loaded dies 26 with end shoulders 27 located in the radial grooves 24 of the die holder 23, and in the cylinder 19 there is a ratchet 28 for engaging with the piston 20 and fixing the position of the cylinder 19 and pusher sleeve 12 relative to the cone 22.

In order to eliminate the possible tearing of the dies 26 from the die holder 23 when removing the packer, the end shoulders 27 (Fig. 2) can be made L-shaped, resting their upper part on the housing of the die holder 23.

The sealing of the contact surfaces between the parts of the packer is provided by the rubber sealing rings shown in figure 1. For temporary (or permanent) blocking of the packer passage channel during its installation and depending on the purpose of the packer, the following are installed on the end section of the barrel 1 (not shown in FIG. 1):

- a shutoff valve (when using a packer to temporarily shut off the formation during pump operation of the well and carry out repair work in it without killing the formation with saline solutions);

- plug (when using the packer as a removable bridge plug for temporary shutdown of the lower layers when moving to overlying horizons or performing various technological operations in the well);

- coupling with a shear saddle under the ball and filter (when using a packer to protect pumps from mechanical impurities during well operation);

- a coupling with a shear saddle for a ball (when used as a lower packer in two-packer layouts with temporary isolation of leakages and perforation intervals of watered formations).

The hydraulic packer works as follows.

A packer connected to the tubing string using a hydraulic or mechanical disconnector is lowered into the production string (not shown in FIG. 1) to a predetermined depth above the perforation zone of the reservoir. In the tubing string and in the barrel 1 of the packer, an excess pressure of the calculated value is created, under the influence of which the screws 21 that hold the pusher sleeve 12 and the piston 20 from axial displacements are first cut, then the pusher sleeve 12 compresses the sealing element 11 and presses the rams 22 26 to the inner surface of the production string. When this ratchet 28, interacting with the piston 20, fixes the position of the cylinder 19 and the sleeve-pusher 12 relative to the cone 22, and the sealing element 11 provides a tight separation of the space in the production casing. Excess pressure in the tubing is dropped to zero, disconnected from the packer using a hydraulic or mechanical disconnector, and removed to the surface. The packer is installed and can withstand pressure drops from above and below during its operation in the well. In this case, the dies 26 reliably hold the packer from moving downward when the pressure drop is from above, and the slips 5 of the armature 4 under the action of liquid pressure from below, transmitted through the radial hole 14 of the push rod 12 and the annular cavity 8, keep the packer from moving upward.

To remove the packer, a tubing string is lowered into the well, connected to the packer barrel 1 using a connecting device, for example an bayonet type overshot (not shown in FIG. 1), and an axial tension of a given value is created. Under the influence of the axial load, the screws 21 are first cut off. After that, the barrel 1 and the anchor 4 are moved up, release the sealing element from compression and through the thrust nut 9, the shell 6, the lock ring 18, the thrust nut 17, the push rod 12, the cylinder 19 and the piston 20 pull the cone 22 from under the dies 26, freeing them from engagement with the production string. Then the packer is removed from the well to the surface.

Claims (2)

1. The hydraulic packer, including a hollow barrel with an annular groove and a number of radial holes, an anchor mounted on the barrel with radially spring loaded slips and a shell, forming an annular cavity with the barrel’s outer surface, a sealing element located on the shell, a push rod sleeve with radial grooves and a radial hole communicating with the annular cavity, the cams mounted in the radial grooves of the pusher sleeve and fixing it on the barrel with the possibility of axial movement, the cylinder fixed mounted on the pushing sleeve, a piston connected to the pushing sleeve by shear screws, a cone rigidly connected to the piston, a ram holder with radial grooves mounted on the barrel by shear screws, rams with end shoulders placed in the radial grooves of the ram holder, ratchet mounted in the cylinder for fixing its position relative to the piston, characterized in that it is equipped with upper and lower thrust nuts with an inner annular protrusion, mounted respectively on the armature and on the push sleeve, the retaining ring ohm mounted on the shell with the possibility of interaction with the annular protrusion of the lower thrust nut, while the shell is made with an external annular protrusion mounted in the anchor with the possibility of axial movement and interaction with the annular protrusion of the upper thrust nut, and the sealing element is placed on the shell between the upper and lower thrust nuts. 2. The hydraulic packer according to claim 1, characterized in that the end shoulders of the dies are L-shaped, resting their upper part on the housing of the ram holder.

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