RU2344270C2 - Drillable packer - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: invention is related to oil and gas production industry and is intended for overlapping of intertubular space and performance of isolating works in case of wells overhaul. Drillable packer contains shaft with notches on external surface, the following components installed on shaft - combined sealing element, extrusion washers, upper and lower rupture screw-thread dies, movable upper and fixed lower supports, fixator in the form of split spring rings in annular bore of movable support. Packer shaft is equipped by left sub with calibrated annular bore and nipple in axial channel, which is rigidly connected to left sub and equipped with fitting valve in axial channel in the form of sleeve with dead bottom and radial holes covered with bushing equipped with throttle. Bushing is connected to sleeve by calibrated shear element. Bottom support is equipped with spring-loaded check valve in the form of body with plug in middle part and radial holes, elastic sealing collar at the lower end, installed with the possibility of interaction with seat in axial channel of lower support.

EFFECT: increase of intertubular space sealing reliability, and also increase of fitting tool functional resources by its multiple usage.

3 cl, 4 dwg

Description

The invention relates to the mining industry and is intended to overlap the annular space of oil and gas wells and insulation work during the overhaul of wells.

Known drillable packer (see Mcl. 5 EV 33/12, Pat. RF №2011792, publ. 04/30/94, Bull. 8), containing a hollow barrel with a sealing element on the outer surface, a retainer plugged in the lower part of the input branch pipe with radial holes, hydraulic cylinder with piston, sleeve. The barrel is connected to the inlet using the left thread. The latch is made in the form of spring-loaded cams in the radial holes of the barrel under the inlet pipe and sleeves with an inner conical surface mounted with the possibility of interaction with the cams.

Packer work

On the tubing string, the packer is lowered into the well to a predetermined depth, overpressure is created by acting on the piston of the hydraulic cylinder with the hydraulic cylinder moving downward relative to the pipe and the barrel, compressing the sealing element until it contacts the wall of the casing pipe. The spring-loaded cams after passing through the sleeve diverge in the radial direction and fix the sealing element.

The disadvantages of the design include

the slips are made of easily drilled material having less strength than the casing material, which reduces the reliability of the fixation of the packer inside the casing;

the slips are cumulated into the sealing element, which when pushing and deforming the latter can lead to rubber leakage into the gaps, as there is no support from the expanding cone or extrusion washers that are not used in this design;

uneven contact along the perimeter of the interaction with the inner surface of the casing pipe;

with an uncontrolled inner diameter of the casing and a fixed stroke size of the rod, barrel and associated cam lock extending beyond the sleeve after deformation of the sealing element, there is a possibility of the cams not coming out and the packer fixing.

This situation is possible due to the lack of information about the pipe wall thickness or the small inner diameter of the casing pipe at the packer landing site.

In addition, the scope of this packer is limited due to the inability to perceive the high pressure drop of the working fluid,

and the hydraulic landing device is disconnected from the packer by rotating the lift string, which also limits the scope in deviated and deviated wells, since it is difficult to control the torque transmitted to the inlet pipe.

Known drillable packer (see AS No. 1832148, Ml. E21B 33/12, publ. 07.08.93, bull. No. 29), adopted as a prototype.

The device consists of a hollow cylindrical body with a threaded thread on the outer surface, a sealing element, extrusion washers, upper slips in the form of annular sectors with radial grooves and hooks. Above the upper slips there is an upper pusher. At the lower end of the hollow cylindrical body, lower slips are placed in the form of annular sectors connected by shear elements with a lower support resting on a lower pusher rigidly connected to the pipe and shank, between which a shear ring is placed.

The upper and lower pushers have clamps in the form of elastic split rings with a triangular cross-section, interacting with a similar thread on the outer surface of the housing when the packer is planted.

Packer work

Using a shear ring, the packer is attached to the planting tool and lowered into the well on the tubing string. An excess fluid pressure is created in the tubing string, which is communicated to the planting tool with an effect on the upper pusher and through a shear ring and a pipe on the lower pusher. This leads to cuff deformation, with a cut of the pins connecting the upper and lower slips with the upper and lower supports. The upper and lower slips move evenly along the conical surface of the supports with overlapping annular space. At the end of the deformation of the cuff with extrusion washers and the engagement of the slips with the casing, the shear ring is cut, which leads to the disconnection of the planting tool from the packer and its removal from the well. Depending on the ongoing technological operation, a tubing with a plunger is lowered into the well to connect to the packer and pump process fluids into the formation, for example, to isolate bottom formation water. If it is necessary to free the axial channel of the wellbore from the packer, it is drilled (the upper part) and is removed from the well by grabbing the drilling tool.

The disadvantages of the design of the packer include:

- the need for additional technological operations associated with additional lifting of the tubing string from the well after the packer is planted, to equip with technological equipment (tools) in order to carry out, for example, insulation work in the under-packer zone;

- since the design of the packer does not imply its equipping with a non-return valve-shutoff, which is necessary during insulation work, with the creation of excess pressure in a predetermined interval, part of the insulating composition after pressure relief can enter both the axial channel of the packer barrel and the axial channel of the lift column pipes, which can lead to an emergency;

- insulating work also implies the supply of the estimated volume of the insulating composition in the under-packer zone. But in some cases, part of the composition is not accepted by the formation and it is necessary to remove it from the pipe tubing string and the annulus of the well by direct or reverse flushing, which is impossible with this packer design, since the tubing string is rigidly connected to the packer;

- the design of the packer shown in the drawing does not correspond to its technical description reflected in the materials of the invention. This can be seen from the fact that the liner, to which the landing tool of known design is connected using a shear ring, is connected to the pipe lift string and is subsequently removed from the well. But this is impossible to do, since in the drawing the packer design is rotated 180 °, which introduces confusion when considering the design of the packer and the principle of its operation.

The technical result that can be obtained by implementing the invention is reduced to the following:

- the possibility of a hydraulic landing using a landing tool with protection of the packer barrel from excessive pressure, which is made of a material having sufficiently low strength properties, for example gray cast iron;

- the ability to disconnect the landing device from the trunk of the packer while maintaining the tightness of the pipe tubing and the ability to supply an insulating composition to the under-packer zone;

- the possibility of cutting off the under-packer zone from the axial channel of the packer barrel after the end of the process;

- the possibility of direct or reverse washing of the axial channel of the pipe riser from excess insulating composition by forming a hydrodynamic connection between the axial channel of the elevator column and the annulus of the well;

- the possibility of multiple use of the landing valve, extracted from the well with the landing device after landing the packer.

An analysis of the inventive step showed the following:

the packer is known (see AS No. 1112114, Ml. EV21B 33/12, publ. 07.09.84, bull. No. 33), in which a plug is installed in the axial channel of the packer barrel, which is removed by the catcher after landing the packer;

- the packer is known (see US Pat. RF No. 2162137, Mkl E21B 33/12), in which a disconnecting element is used, for example a shear ring, which connects the packer to the landing tool. The planting tool is then removed from the well. After unpacking, a special nipple is inserted into the packer barrel on the tubing with sealing the annular gap between them with the sealing rings;

- known drilled mechanical packer (see US Pat. RF No. 2.236.556 Ml. E21B 33/12, publ. September 20, 2004), which is designed to block the annular space of oil and gas wells and the implementation of the technology of isolation of bottom water. A cuff-type check valve is installed in the axial channel of the packer barrel, which provides free passage of the insulating composition to the sub-packer zone and the hydraulic connection of the latter with the axial channel of the packer barrel from the sub-packer zone after the supply of the insulating composition to the pipe tubing under pressure is stopped.

The technical result is achieved by the fact that the drilled packer contains a barrel, on the outside of which a threaded notch is made, a combined sealing element covered by extrusion washers, upper and lower explosive dies with upper and lower supports with expandable cones, a latch in the form of split spring rings installed in an annular bore of the upper movable support, the lower support being equipped with a spring-loaded check valve in the form of a housing with a plug in the middle part and radial holes above its location, as well as an elastic sealing cuff. The left sub is connected to the packer barrel and the nipple, which is equipped with a landing valve in the form of a glass with a blind bottom and radial channels, blocked in the initial position by a sleeve with a throttle, which is connected to the body of the glass, calibrated by a shear element, and the left sub is connected to the barrel by a calibrated ring jumper at the place of execution of the annular groove, and the nipple is installed in the axial channel of the packer barrel with the possibility of forming a movable connection with it after the destruction of the annular bridge.

When conducting patent research on scientific, technical and patent literature, no drillable packers were found in which hydraulic landing is carried out using a landing device mechanically connected through a special left sub with an annular groove, with a nipple entering the axial channel of the packer barrel, an annular gap between which is blocked by sealing elements. In the axial channel of the nipple, a seat valve in the form of a cup is mounted on the thread, in the axial channel of which a sleeve with a throttle channel is installed connected with the housing of the landing valve calibrated by a shear element. The axial channel of the packer barrel is blocked by a shoe, which is the lower support, equipped with a spring-loaded check valve with an elastic cuff.

The design of the drilled packer is designed to overlap the annulus in the wells, where it is necessary to conduct insulating work from the entry of bottom water and is illustrated by the drawings,

where in Fig.1 - design drilled packer in the initial transport position;

figure 2 - drilled packer in the position of the hydraulic landing and overlapping the annular space of the well with a sealant with a gap of the left sub on the annular groove and disconnected from the barrel;

figure 3 - opening of the hydraulic connection of the axial channel of the nipple with the barrel of the packer and the annulus, isolation;

figure 4 - the relative position of the parts of the packer during the formation of the hydrodynamic connection of the axial channel of the pipe lift column through the axial channel of the nipple with the annular space of the well and the closed check valve in the shoe.

Drill packer consists of a barrel 1 with notches 2 on its outer side, connected through the left sub 3 with a hollow plunger of a hydraulic landing device of known design, for example (see figure 1).

The left sub 3 is connected to the nipple 4, which is passed into the axial channel 5 of the barrel 1 of the packer with the possibility of forming a movable connection with it. At the junction with the barrel 1, the left sub 3 is equipped with an annular groove 6. In the axial channel 7 of the nipple 4, a seat valve is fixed on the thread in the form of a cup 8 with a blind bottom 9 and radial holes 10 in the side surface, blocked by a sleeve 11 with a throttle 12, which is connected with the body of the glass 8 calibrated shear elements 13.

On the outer surface of the barrel 1, at the place of the notches 2, an upper movable support 14 is installed with a retainer in the form of split spring rings 15 in a cylindrical bore 16. The upper movable support 14 interacts with the upper explosive dies 17, which interact with the expanding cone 18, which through the upper the extrusion washers 19 rests on a combined sealing element 20, supported through the lower extrusion washers 21 on the lower expansion cone 22, which is included in the mating cone of the lower explosive dies 23, supporting I, in turn, to the end of the body 24 of the shoe of the valve, which is mounted on the lower end of the barrel 1 of the packer.

In the housing 24 of the shoe valve, in its axial channel, a check valve housing 25 is installed. Its axial channel 26 is equipped with a plug 27 in the middle part and radial openings 28 hydraulically connected to the cavity of the axial channel 5 of the packer barrel 1. An elastic sealing sleeve 29 is mounted to the lower end of the check valve body 25, fixed by a nut 30. In the initial position, the check valve body 25 preloaded by a spring 31 to the seat in the plug 27, which is installed inside the axial channel 32 of the perforated plug 33. The upper 17 and lower 23 explosive dies are connected by annular jumpers 34 and 35, respectively, the thickness of the cat It is determined from the condition of sequential transmission and perception of axial load during packer landing, with rupture-destruction at the first stage of the annular bridge 35 of the lower explosive dies 23. On the outside of the upper 17 and lower 23 explosive dies, a notch 36 and at least two annular grooves in which split spring rings 37 are installed facing an acute angle to the casing pipe wall. They are made of durable material, such as hardened steel. The left sub 3 of the upper end is connected to the hollow stem 38 of the hydraulic landing device.

Drill Packer Operation

A hydraulic landing device is connected to the lower end of the pipe string, to the hollow stem of which a drillable packer is connected through the left sub 3, and the assembly lowers to a predetermined depth.

The working fluid is supplied under the design pressure into the axial channel of the pipe tubing string and a hydraulic landing device. When the parts of this device act on the end of the upper movable support 14 from the outside, the assembly moves along the outer surface of the barrel 1 with the lower expanding cone 22 inserted into the lower explosive dies 23. When the axial load is calculated, the annular bridge 35 breaks and the explosive dies 23 move in the radial the direction with the introduction of an acute angle of the edges of the split spring rings 37 into the wall of the casing pipe and fixing the drillable packer with the lower bursting dies 23.

Further axial loading deforms the combined sealing element 20, bringing the casing to contact with the pipe wall and closing the annular gap with the lower 21 and upper extrusion washers 19. When the axial load is calculated and the upper tensile dies 17 are pushed onto the conical surface of the upper expanding cone 18, the annular is destroyed jumpers 34 and the movement of the upper explosive dies 17 in the radial direction with the introduction of split spring rings 37 into the body of the casing pipe Lonna.

The upper movable support 14 with a retainer in the form of split spring rings 15 is located at the level of the notches 2 on the packer barrel 1, which leads to their introduction into the notches 2 and fixation of the packer inside the casing with overlapping annular gap with the combined sealing element 20.

After the packer is planted, the tared annular bridge 6 is destroyed, connecting the left sub 3 with the barrel 1, which leads to the disconnection of the hydraulic landing device from the barrel 1 of the packer.

With a further increase in the pressure of the working fluid, which is transmitted to the cross-sectional area of the sleeve 11 of the landing valve, the calibrated shear element 13 is destroyed and the sleeve 11 is moved all the way into the blind bottom 9 of the glass 8.

In this case, the cavity of the axial channel 7 of the nipple 4 through the radial holes 10 freely communicates with the cavity of the axial channel 5 of the barrel 1 of the packer.

After depressurization in the pipe pipe string, the elastic sealing sleeve 29 of the non-return valve is brought into contact with the seat in the plug 27 by excessive pressure under the packer and the force of the compressed spring 31, as a result of which the hydraulic connection of the sub-packer cavity with the axial channel 5 of the barrel 1 of the packer is terminated. The tension of the pipe pipe string moves the nipple 4 up inside the axial channel 5 of the barrel 1 of the packer with the output of the nipple 4 from it and the location above the packer.

In this position, a direct supply of washing liquid is carried out along the axial channel of the pipe tubing through the axial channel 7 of the nipple 4 into the annulus of the well to remove excess insulating composition from the well.

At the end of the insulation work, the lift pipe string is lifted along with the hydraulic landing device and nipple 4 to the surface.

The design of the drilled packer suggests, if necessary, to carry out its drilling.

Claims (3)

1. Drillable packer containing a barrel with notches on the outer surface, a combined sealing element mounted on the barrel, extrusion washers, upper and lower bursting dies, movable upper and fixed lower bearings, a retainer in the form of split spring rings in the annular bore of the movable bearing, characterized in that the packer’s barrel is equipped with a left sub with a calibrated annular groove and a nipple in the axial channel rigidly connected to the left sub and equipped with a seat valve in the axial channel in e cups with a blind bottom and radial holes overlapped by a sleeve with a bottom equipped with a throttle, and the sleeve is connected to the glass by a calibrated shear element, and the lower support is equipped with a spring-loaded check valve in the form of a body with a cap in the middle part and radial holes, an elastic sealing cuff on the bottom the end installed with the possibility of interaction with the seat in the axial channel of the lower support. 2. Drillable packer according to claim 1, characterized in that the bursting dies are equipped with annular jumpers and split spring rings installed in the annular grooves. 3. Drillable packer according to claim 2, characterized in that the cross section of the annular bridge of the lower explosive dies is taken to be less than the cross section of the annular bridge of the upper explosive dies.

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