CN107829705B - Expanding packer assembly and packer - Google Patents

Abstract

The invention relates to the technical field of well drilling or well completion, in particular to an expansion type packer assembly and a packer.

Description

Expanding packer assembly and packer

Technical Field

The invention relates to the technical field of well construction or well completion, in particular to an expansion packer assembly and a packer.

Background

In the downhole operation of oil and gas field development, and the operations of drilling, cementing, testing, well completion and the like, because the existing packer operates in the downhole and is more than the corrosive fluid contact, the existing expansion pipe made of metal is easily corroded by the corrosive fluid, so that the packer fails.

Disclosure of Invention

The invention aims to: the problem of present packer corrosion inefficacy is solved, an expanding packer subassembly and packer are provided, above-mentioned problem can effectively be alleviated.

In order to achieve the purpose, the invention adopts the technical scheme that:

the utility model provides an expansion packer subassembly and packer, includes the expansion pipe, the expansion pipe includes skeleton, inlayer and skin, the inlayer sets up the skeleton is inboard, the skin sets up the skeleton outside, the skeleton is made by the metal, the expansion pipe still is provided with the protection tube that rubber made outward.

Preferably, the protection tube comprises two sections of protection tube segments which are arranged next to each other, the end portions, next to each other, of the two protection tube segments are unfixed free ends, and the other ends of the two protection tube segments are fixed.

The patent also discloses an expansion packer, which comprises the packer component, a central pipe, a sleeve and a plugging component, wherein the expansion pipe is sleeved on the central pipe, one end of the expansion pipe is fixedly connected with the central pipe, the sleeve is sleeved outside the central pipe,

the plugging part comprises a starting piece, a starting nail, a plugging piece and a plugging nail, the starting piece is arranged between the central tube and the sleeve and is fixedly connected with the central tube or the sleeve through the starting nail, the plugging piece is arranged between the central tube and the sleeve and is fixedly connected with the central tube or the sleeve through the plugging nail,

a closed expansion cavity is formed among the central tube, the expansion tube, the sleeve and the starting piece, a starting cavity is arranged between the starting piece and the plugging piece, a plugging cavity is arranged on one side of the plugging piece far away from the starting piece,

the central tube is provided with a starting hole and a plugging hole, the starting hole is communicated with the inner cavity of the central tube and the starting cavity, the plugging hole is communicated with the inner cavity of the central tube and the plugging cavity, the cross-sectional area of the plugging nail is larger than that of the starting nail,

the closure having a suitable dimension in the direction of the central tube axis, the suitable dimension being such that the closure is able to block the activation hole when the closure is able to move,

preferably, the packer further comprises a one-way valve disposed at the expansion chamber inlet such that fluid entering the expansion chamber must pass through the one-way valve to enter.

Preferably, the check valve comprises a valve core pipe and an elastic pipe, one end of the valve core pipe is sealed, a valve hole is formed in the diameter direction of the valve core pipe, the elastic pipe is sleeved outside the valve core pipe, and the valve hole is covered by the elastic pipe.

Preferably, the valve core is provided with an anti-slip structure to prevent the elastic tube from falling off.

Preferably, the end face of the plugging piece, which is in contact with the plugging cavity, is a lower end face, the end face opposite to the lower end face is an upper end face, and the area of the lower end face is larger than that of the upper end face.

Preferably, the expansion tube includes a frame, an inner layer disposed inside the frame, and an outer layer disposed outside the frame, the frame being made of metal.

In conclusion, due to the adoption of the technical scheme, the beneficial effects of the application are as follows: the metal is adopted as the framework, so that the rigidity of the expansion pipe can be improved, the blocking condition caused by the deformation and expansion of the expansion pipe in the well descending process of the packer is reduced, and the well descending of the packer is easier; in addition, the inner layer and the outer layer are arranged inside and outside the metal framework to isolate corrosive liquid, so that the expansion pipe is prevented from being penetrated by a corrosive hole, and the service life and the reliability of the expansion pipe are improved; in addition, the outer layer is prevented from being scratched and damaged in the well descending process by the protection pipe, so that the expansion pipe is prevented from being penetrated through by a corrosion hole, the effective operation of the packer is guaranteed, and the reliability of the packer is improved.

Drawings

FIG. 1 is a schematic structural view of a packer of the present application;

FIG. 2 is an enlarged partial schematic view of AA in FIG. 1;

FIG. 3 is a schematic diagram of a portion of CC shown in FIG. 1;

FIG. 4 is an enlarged view of BB of FIG. 3;

the labels in the figure are: 1-upper joint, 2-lower joint, 3-central tube, 31-central tube lumen, 32-actuation hole, 33-blocking hole, 4-expansion tube, 41-skeleton, 42-inner layer, 43-outer layer, 5-sleeve, 6-blocking component, 61-actuation pin, 62-actuation member, 63-blocking member, 631-blocking member upper end face, 632-blocking member lower end face, 64-blocking pin, 7-check valve, 71-elastic tube, 72-valve core tube, valve hole, 722-free section, 724-root section, 7241-anti-slip structure, 73-fastening ring, 81-expansion cavity, 82-actuation cavity, 83-blocking cavity, 9-protective tube, 91-upper protective tube segment, 92-lower protective tube segment.

Detailed Description

The present invention will be described in detail below with reference to the accompanying drawings.

Because the packer all is in the operation in the pit, be more than corrosive fluid contact, the expansion pipe 4 that present metal was made receives corrosive fluid easily, thereby make to seal and separate the inefficacy, consequently, in order to further improve the packing reliability of packer, the patent discloses a packer subassembly, including expansion pipe 4 and the protection tube 9 of setting outside expansion pipe 4, expansion pipe 4 includes skeleton 41, inlayer 42 and skin 43, inlayer 42 sets up at skeleton 41 inboard, skin 43 sets up in the skeleton 41 outside, skeleton 41 is made by the metal, protection tube 9 is made by rubber, compare in directly adopting the tubular metal resonator as expansion pipe 4, this scheme makes metal skeleton 41 can not contact with the fluid, thereby avoid metal skeleton 41 to be corroded by corrosivity, further improve the seat and seal the reliability. Specifically, the entire frame 41 is cylindrical, that is, the frame 41 is a metal cylinder or a metal pipe, and of course, the metal frame 41 is a support for providing force, so the metal frame 41 may also be a mesh structure which is cylindrical as a whole, thereby saving material. Specifically, the outer layer 43 is attached to the frame 41 by a vulcanization manufacturing method, and the protection effect is better.

In the actual use process, the packer can fail because the expansion pipe 4 is corroded and penetrates radially, and the expansion pipe 4 is not corroded because the adhesion layers which are not easy to corrode, namely the inner layer 42 and the outer layer 43, are adhered on the inner side and the outer side of the metal framework 41, but the metal framework 41 is still corroded in the actual use process. The inventors have studied and analyzed, and found that the outer layer 43 is damaged: in the packer in-process of going into the well, because expansion pipe 4 exposes outside, expansion pipe 4 can take place to scrape with the wall of a well to destroy expansion pipe 4's surface, the influence seals the effect of separating, and is specific, can destroy packer's skin 43, makes metal framework 41 expose outside, and corrosive fluid can corrode naked part, and along with the lapse of time, corrosive fluid can further corrode not naked part, makes expansion pipe 4 lose effect. If the corrosion is severe, there may be radial penetration of the expansion tube 4 such that the expansion chamber 81 can no longer be sealed and the expansion tube 4 cannot expand, rendering the packer ineffective. In order to solve the problem that the expansion pipe 4 is penetrated by radial corrosion to cause the packer to fail, a layer of protection device is needed to be arranged outside the inner layer 42 and the outer layer 43 which are arranged inside and outside the metal framework 41, so that the outer layer 43 of the expansion pipe 4 is prevented from being damaged by the packer in the well descending process. Specifically, the protective tube 9 made of rubber materials is sleeved outside the expansion tube 4, the wall thickness of the protective tube 9 is 0.2mm-5mm, therefore, an inner layer 42 and an outer layer 43 are arranged inside and outside the metal framework 41 to isolate corrosive liquid, the protective tube 9 is adopted to avoid scraping and damaging the outer layer 43 in the well descending process, the expansion tube 4 is protected from being penetrated by a corrosive hole, and the effective operation of the packer is guaranteed.

The rubber protection tube 9 is arranged outside the expansion tube 4, when the expansion tube 4 expands outwards in the radial direction, although the rubber protection tube 9 has elasticity, the outer protection tube 9 has larger resistance to the expansion of the expansion tube 4, the expansion tube 4 is not easy to expand, the pressure required is larger, the resources are wasted, and the larger the pressure is, the larger the risk is. Thus, in order to reduce the pressure in the central tube lumen 31 required for expanding the expansion tube 4, the protective tube 9 is fixed at both ends, while the protective tube 9 is cut into two ends from a central region, in particular, as shown in fig. 2, the protective tube 9 comprises two protective tube segments arranged next to each other, as shown in fig. 1 and 2, an upper protective tube segment 91 and a lower protective tube segment 92, respectively, the ends of the two protective tube segments next to each other being loose free ends, as shown in fig. 2, in which the upper protective tube segment 91 and the lower protective tube segment 92 are butted next to each other, the next ends being free ends, the other ends of the upper protective tube segment 91 and the lower protective tube segment 92 being fixed, more particularly, one end of the upper protective tube segment 91 being fixed to the upper joint 1, one end of the lower protective tube segment 92 being fixed to the lower joint 2, the two protective tube segments being next to each, therefore, when the expansion pipe 4 is expanded, the two protection pipe segments are separated by the end parts which are close to each other, the expansion pipe 4 is expanded from the separated areas until the expansion pipe contacts the casing 5 or the well wall arranged at the bottom of the well, therefore, the resistance formed by the protection pipe 9 when the expansion pipe 4 is expanded can be greatly reduced, the pressure of the inner cavity 31 of the central pipe required for expanding the expansion pipe 4 can be reduced, namely, the first preset value can be reduced, the construction risk is reduced, and the construction cost is reduced. For the purpose of further reducing the first preset value, reducing the construction risk and reducing the construction cost, rubber joints are arranged at two ends of the expansion pipe 4, the expansion pipe 4 is fixed through the rubber joints, that is, the expansion pipe 4 is fixed with other parts through the rubber joints, specifically referring to fig. 1, the upper end of the expansion pipe 4 is in threaded connection with a protection pipe 9, the protection pipe 9 is in threaded connection with the upper joint 1, the protection pipe 9 is made of rubber, and the protection pipe 9 is equivalent to the rubber joints in the scheme. Compared with the fact that the expansion pipe 4 is directly fixedly connected with other metallic parts, the rubber joint is fixed with the other metallic parts, the expansion pipe 4 is not rigidly connected with the other metallic parts but has a certain flexible or elastic connection mode, the expansion pipe 4 is easier to expand, the required expansion force is smaller, and therefore the first preset value can be further reduced, the construction risk is reduced, and the construction cost is reduced.

As shown in fig. 1 to 4, an expandable packer comprises an upper joint 1, a lower joint 2, a central tube 3, an expandable tube 4, a sleeve 5 and a plugging component 6, wherein the upper end of the central tube 3 is connected with the upper joint 1, the lower end of the central tube is connected with the lower joint 2, the expandable tube 4 is sleeved on the central tube 3, and one end of the expandable tube 4 is fixedly connected with the central tube 3, that is, the expandable tube 4 and the central tube 3 can be in direct contact to form a fixed connection or form an indirect fixed connection through an intermediate piece, as shown in fig. 1, the upper end of the expandable tube 4 is in threaded connection with one end of an upper protection tube segment 91, and meanwhile, the one end of the upper protection tube segment 91 is in threaded connection with the upper joint 1, and the upper joint 1 is. The other end of the expansion pipe 4 is fixedly connected with one end of the lower protection pipe segment 92, the one end of the lower protection pipe segment 92 is in threaded connection with the sleeve 5, the sleeve 5 is in threaded connection with the lower joint 2, and the central pipe 3 is connected with the lower joint 2, so that the expansion pipe 4 is in threaded connection with the central pipe 3 through the lower protection pipe segment 92, the sleeve 5 and the lower joint 2.

The sleeve 5 is sleeved outside the central tube 3, the plugging part 6 comprises a starting piece 62, a starting nail 61, a plugging piece 63 and a plugging nail 64, the starting piece 62 is arranged between the central tube 3 and the sleeve 5 and fixedly connected with the central tube 3 or the sleeve 5 through the starting nail 61, the plugging piece 63 is arranged between the central tube 3 and the sleeve 5 and fixedly connected with the central tube 3 or the sleeve 5 through the plugging nail 64,

a closed expansion cavity 81 is formed among the central tube 3, the expansion tube 4, the sleeve 5 and the actuating element 62, an actuating cavity 82 is formed between the actuating element 62 and the blocking element 63, a blocking cavity 83 is formed on one side of the blocking element 63 far away from the actuating element 62,

the central tube 3 is provided with a starting hole 32 and a blocking hole 33, the starting hole 32 is communicated with the inner cavity 31 and the starting cavity 82 of the central tube 3, the blocking hole 33 is communicated with the inner cavity 31 and the blocking cavity 83 of the central tube 3, the section area of the blocking nail 64 is larger than that of the starting nail 61,

in the axial direction of the central tube 3, the blocking piece 63 has a suitable size, and when the blocking piece 63 can move due to the suitable size, the blocking piece 63 can block the starting hole 32, so that the starting hole 32 can be blocked to communicate the inner cavity 31 of the central tube 3 with the blocking cavity 83, namely, the inner cavity 31 of the central tube 3 is not communicated with the blocking cavity 83.

Specifically, referring to fig. 3, the central tube inner cavity 31 communicates with the actuating cavity 82 through the actuating hole 32, before the actuating hole 32 is not closed, the pressure of the central tube inner cavity 31 is equal to the pressure of the actuating cavity 82, the lower end surface 632 of the actuating member 62 is subjected to pressure so that the actuating member 62 tends to move upward and thus to shear the actuating pin 61, when the pressure of the central tube inner cavity 31 rises to reach a first preset value and less than a second preset value, the actuating member 62 shears the actuating pin 61 and moves upward until the actuating cavity 82 communicates with the expansion cavity 81, as shown in fig. 3, after the actuating member 62 moves upward and is separated from the sleeve 5, the actuating cavity 82 communicates with the expansion cavity 81 through the check valve 7 so that the central tube inner cavity 31 communicates with the expansion cavity 81, the fluid of the central tube inner cavity 31 flows to the expansion cavity 81 under the pressure, and the expansion tube 4 starts to expand outward when the pressure of the expansion cavity 81 equals to the first preset value due to the, until the expansion pipe 4 is shielded by other objects, specifically, the expansion pipe 4 is shielded by the oil casing 5, and thus, interlayer packing is completed.

Because the area of the lower end surface 632 of the plugging member is greater than the area of the upper end surface 631 of the plugging member, as shown in fig. 3, the plugging chamber 83 communicates with the central tube lumen 31 through the plugging hole 33, and although the starting pin 61 can be cut when the pressure in the central tube lumen 31 is between the first preset value and the second preset value, because the cross-sectional area of the plugging pin 64 is greater than the cross-sectional area of the starting pin 61, the plugging pin 64 needs a larger force to be cut than the starting pin 61, therefore, when the starting pin 61 is cut by the starting pin 62, the plugging pin 64 is not cut by the plugging member 63, when the pressure in the expandable tube 4 is further increased to reach the second preset value, the plugging pin 64 is cut by the plugging member 63, and the plugging member 63 moves up to plug the starting hole 32, so that the communication passage between the central tube lumen 31 and the expandable chamber 81 is blocked, thereby achieving blocking and plugging.

Furthermore, the packer further comprises a one-way valve 7, as shown in fig. 3 and 4, the one-way valve 7 is arranged at the inlet of the expansion cavity 81, so that the fluid entering the expansion cavity 81 can enter only through the one-way valve 7, the fluid entering the expansion cavity 81 through the one-way valve 7 can be always remained in the expansion cavity 81 and can not flow back, when pressure fluctuation occurs in the underground, the whole volume of the expansion cavity 81 can not be reduced, and the packing reliability is higher.

Therefore, the one-way valve 7 is adopted to prevent backflow in the expansion cavity 81, so that permanent setting can be realized and setting is reliable; the starting piece 62 and the starting nail 61 are adopted, so that the packer starts to pack when the pressure of the central tube 3 reaches the set pressure, the packing effect is ensured, and the packing at an unexpected position is avoided; adopt shutoff piece 63 and shutoff nail 64 for shutoff starting hole 32 when center tube 3 pressure reaches the setting value, namely cut off the influent stream of expansion chamber 81, avoid exploding because of expansion chamber 81 pressure is too big, simultaneously, the shutoff piece 63 of cutting off shutoff nail 64 shutoff starting hole 32 can avoid flowing into center tube inner chamber 31 by the liquid that single-way valve 7 spilt, can further guarantee that expansion chamber 81 volume is unchangeable, further guarantees the packing effect.

Specifically, the check valve 7 may adopt a conventional check valve, and of course, other novel check valves 7 may also be adopted, for example, preferably, as shown in fig. 4, the check valve 7 includes a valve core tube 72 and an elastic tube 71 with one end closed, a valve hole 722 is arranged in the diameter direction of the valve core tube 72, the elastic tube 71 is sleeved outside the valve core tube 72, and the elastic tube 71 covers the valve hole 722, so that, when the fluid pressure in the inner cavity of the valve core tube 72 reaches a certain degree, the fluid expands the elastic tube 71 through the valve hole 722, so that a gap exists between the elastic tube 71 and the valve core tube 72, and the elastic tube 71 cannot cover the valve hole 722, so that the fluid in the valve core tube 72 flows out of the valve core tube 72 through the valve hole 722, the gap between the expanded elastic tube 71 and the valve core tube 72, that is, and flows into the expansion cavity 81; when the pressure outside the valve core pipe 72, that is, the pressure outside the elastic pipe 71 is equal to the pressure in the inner cavity of the valve core pipe 72, the elastic pipe 71 covers the valve hole 722 again under the action of the elastic restoring force of the elastic pipe 71, the valve core pipe 72 is tightly wrapped, the flow channel of the inner cavity of the valve core pipe 72 and the expansion cavity 81 is cut off, and the elastic pipe 71 tightly wraps the valve core pipe 72 and covers the valve hole 722, so that the fluid in the expansion cavity 81 cannot flow into the valve core pipe 72 from the valve hole 722, and the function of the check valve 7 which can only flow into the expansion cavity 81 from the valve core pipe 72 is realized, in addition, when the pressure in the inner cavity of the valve core pipe 72 is smaller than the pressure in the expansion cavity 81, the fluid pressure in the expansion cavity 81 presses and holds the elastic pipe 71, so that the elastic pipe 71 tightly presses and holds the valve core pipe 72, that is tightly wrapped around the valve core pipe 72, compared with other check valves 7, backflow is difficult, making the pack-off more reliable.

More specifically, the inner diameter of the elastic tube 71 is smaller than the outer diameter of the spool tube 72, so that the elastic tube 71 is in a radially tensioned state when the elastic tube 71 is sleeved on the spool tube 72. Preferably, the elastic tube 71 is made of rubber.

The valve core is provided with an anti-slip structure 7241 to prevent the elastic tube 71 from falling off, specifically, as shown in fig. 4, the outer surface of the valve core tube 72 is provided with a circle of bulges along the circumferential direction, the cross section of the bulges is triangular, so that the elastic tube 71 is sleeved on the bulges and is difficult to fall off, and the reliability of the one-way valve 7 is better; of course, the anti-slip structure 7241 may also take other forms, specifically, a circle of groove is provided outside the valve core tube 72 along the circumferential direction, the elastic tube 71 covers the groove, and a rope or wire is used to wind the elastic tube 71 outside the elastic tube 71 and make the elastic tube 71 be embedded into the groove, that is, the rope or wire is wound in the groove area.

The valve hole 722 divides the valve core pipe 72 into two sections in the axial direction of the valve core pipe 72, namely a free section 723 and a root section 724, the valve core pipe 72 is fixed through the root section 724, the check valve 7 further comprises a fastening ring 73, the fastening ring 73 is sleeved on the elastic pipe 71, so that the elastic pipe 71 is fastened on the root section 724, the elastic pipe 71 is not easy to fall off, and the backflow stopping reliability of the check valve 7 is better; moreover, only the elastic tube 71 is fastened on the root section 724, but the elastic tube 71 and the free section 723 are not fastened, at this time, when the fluid in the inner cavity of the valve core tube 72 expands the elastic tube 71, only the part attached to the free section 723 generates a channel to the expansion cavity 81, and the part fixed with the root section 724 by the fastening ring 73 does not have a channel, compared with the case where the fastening ring 73 is not fixed, when the elastic tube 71 fixed by the fastening ring 73 is expanded by the fluid pressure, only one end of the elastic tube 71 can allow the fluid to pass through, but not both ends of the elastic tube 71 can allow the fluid to pass through as the fastening ring 73 does, so that the elastic tube 71 can be prevented from loosening caused by the fluid passing through both ends of the elastic tube 71, specifically, as shown in fig. 4, the root section 724 of the valve core tube 72 is provided with a bulge, that is an anti-slip structure 7241, but if the elastic tube 71 is not fixed outside the valve core tube 72 by, then, the fluid from the inside of the spool tube 72 may expand the elastic tube 71 and may expand the elastic tube 71 at the protrusion, thereby disabling the anti-slip structure 7241 of the elastic tube 71, and therefore, the fastening rings 73 are provided, and the fluid can be prevented from flowing out from both ends of the elastic tube 71. Preferably, the anti-slip structure 7241 is formed by a protrusion, and the fastening ring 73 is closely adjacent to the protrusion, so that the anti-slip performance of the elastic tube 71 is further improved.

Specifically, as shown in fig. 3, an end surface of the block piece 63 contacting the block cavity 83 is a lower end surface 632, an upper end surface 631 is provided opposite to the lower end surface 632, and the area of the lower end surface 632 is larger than that of the upper end surface 631. After the starting hole 32 is opened to make the fluid in the central tube inner cavity 31 enter the starting cavity 82, because the upper end surface 631 of the plugging member 63 is a component of the plugging cavity 83, the fluid pressure borne by the upper end surface 631 of the plugging member 63 is the same as the pressure in the central tube inner cavity 31, and at this time, because the plugging hole 33 makes the pressure in the plugging cavity 83 be the same as the pressure in the central tube 3, the area pressure of the lower end surface 632 of the plugging member is larger than the area of the upper end surface 631, so that the stress of the lower end surface 632 of the plugging member is larger than the stress of the upper end surface 631, the resultant force direction of the fluid pressure on the plugging member 63 is upward, the plugging member 63 tends to move towards the starting hole 32, and the plugging member 63 is possible.

Any modification, equivalent replacement, and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (6)

1. An expandable packer assembly, characterized in that, includes expansion pipe (4), expansion pipe (4) include skeleton (41), inlayer (42) and skin (43), inlayer (42) set up in skeleton (41) inboard, skin (43) set up in the skeleton (41) outside, skeleton (41) are made by the metal, the skeleton is the network structure of barrelling for whole,

the expansion pipe (4) still is provided with protection tube (9) that rubber was made outward, protection tube (9) include two sections protection tube subsections (91,92) of being close to the arrangement, and the tip that two protection tube subsections (91,92) are close to each other is unsettled free end, and the other end of two protection tube subsections (91,92) is all fixed.

2. A packer, characterized by comprising the packer assembly of claim 1, a base pipe (3), a sleeve (5) and a plugging member (6), wherein the expansion pipe (4) is sleeved on the base pipe (3), one end of the expansion pipe (4) is fixedly connected with the base pipe (3), the sleeve (5) is sleeved outside the base pipe (3),

the plugging part (6) comprises an actuating piece (62), an actuating nail (61), a plugging piece (63) and a plugging nail (64), the actuating piece (62) is arranged between the central tube (3) and the sleeve (5) and fixedly connected with the central tube (3) or the sleeve (5) through the actuating nail (61), the plugging piece (63) is arranged between the central tube (3) and the sleeve (5) and fixedly connected with the central tube (3) or the sleeve (5) through the plugging nail (64), a closed expansion cavity (81) is formed between the central tube (3), the expansion tube (4), the sleeve (5) and the actuating piece (62), an actuating cavity (82) is arranged between the actuating piece (62) and the plugging piece (63), and a plugging cavity (83) is arranged on one side of the plugging piece (63) far away from the actuating piece (62),

the central tube (3) is provided with a starting hole (32) and a blocking hole (33), the starting hole (32) is communicated with the inner cavity (31) of the central tube (3) and the starting cavity (82), the blocking hole (33) is communicated with the inner cavity (31) of the central tube (3) and the blocking cavity (83), the cross-sectional area of the blocking nail (64) is larger than that of the starting nail (61),

the closure (63) has a suitable dimension in the axial direction of the central tube (3), said suitable dimension being such that the closure (63) can block the activation hole (32) when the closure (63) is movable.

3. A packer according to claim 2, further comprising a one-way valve (7), the one-way valve (7) being arranged at the expansion chamber (81) inlet such that fluid entering the expansion chamber (81) must pass the one-way valve (7) before it can enter.

4. A packer according to claim 3, wherein the one-way valve (7) comprises a valve core tube (72) with one closed end and an elastic tube (71), a valve hole (722) is formed in the diameter direction of the valve core tube (72), the elastic tube (71) is sleeved outside the valve core tube (72), and the elastic tube (71) covers the valve hole (722).

5. A packer as claimed in claim 4, characterised in that the spool is provided with anti-slip formations (7241) to prevent the elastomeric tube (71) from falling out.

6. A packer according to claim 2, characterised in that the end surface of the block piece (63) in contact with the block cavity (83) is a lower end surface (632), opposite the lower end surface (632) is an upper end surface (631), the lower end surface (632) having a larger area than the upper end surface (631).

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