A timed release packer

Abstract

The present invention discloses a timed unsealing packer, comprising an upper joint, an upper connecting pipe, a lower connecting pipe, a lower joint, a rubber cylinder, a spacer ring, a thrust sleeve, an upper piston and a lower piston in the prior art, and also comprising a newly added one-way valve, a timed unsealing mechanism and a bursting disc, and making partial changes to the upper connecting pipe, the lower connecting pipe, the upper piston and the lower piston; the one-way valve is arranged in the liquid inlet channel of the piston chamber, and the high-pressure liquid is sealed after the seat is pressed; the timed unsealing mechanism is arranged in the liquid outlet channel of the piston chamber, and after the piston chamber is pressed, the potassium chloride inside is mixed with the liquid in the well to form a potassium chloride solution, so that the soluble nail begins to dissolve, and after the soluble nail dissolves, the pressure in the piston chamber is unloaded, and unsealing is achieved. The timed unsealing packer of the present invention has the following advantages: there is no need to lift the tubing string, and there is no problem of insufficient lifting force or drill stuck; the conventional rubber cylinder is used, which can meet the requirements of high temperature and high pressure; the unsealing timing starts after the well seat is sealed, and the construction technology and time requirements are low.

Description

Technical Field

[0001] The present invention relates to the technical field of oil and gas production tools, and in particular to a timed release packer. Background Art

[0002] Existing methods for releasing packers used in multi-layer fracturing construction mostly involve lifting the tubing string with a certain force and then breaking the releasing shear pins to release the packer. However, during the actual releasing process, due to the presence of multiple packers, the releasing shear pins need to be broken simultaneously before the packers can be released. The more packers there are, the greater the releasing force. Moreover, the packers may be stuck with sand to varying degrees, which further increases the lifting force for releasing. Ultimately, the releasing force may exceed the load of the tubing string, resulting in a drill sticking accident.

[0003] There are also soluble packers on the market, which are packers that use soluble rubber tubes or other components made of soluble materials. This type of packer begins to dissolve on a timed basis when it is lowered into the well, which places strict requirements on construction plans and time, and has a high failure rate. Packers that use soluble rubber tubes cannot meet the requirements of high temperature and high pressure due to material problems. Summary of the Invention

[0004] To this end, the present invention provides a timed release packer that does not require lifting the tubing string and does not use a soluble rubber cartridge. The release time is not calculated from the time the packer is lowered into the well, but from the time the packer is set, so as to solve the technical problems in the prior art that sufficient lifting force is required, the drill is easily stuck, the construction technology and time requirements are strict, and the requirements of high temperature and high pressure are not met.

[0005] In order to achieve the above object, the present invention provides the following technical solutions:

[0006] A timed unsealing packer, the timed unsealing packer has a piston cavity, a liquid inlet channel is provided between the piston cavity and the water eye, the timed unsealing packer also includes a one-way valve and a timed unsealing mechanism, a liquid outlet channel is provided between the piston cavity and the water eye, potassium chloride is placed in the piston cavity, the one-way valve is arranged in the piston cavity and installed in the expanded hole of the liquid inlet channel located in the piston cavity, the timed unsealing mechanism includes a soluble nail, a gasket, a sealing ring and a nut, the soluble nail is T-shaped and the large end is facing inward and is arranged in the liquid outlet channel The backing ring is located in the expanded hole in the piston cavity, and is sleeved on the outside of the small end of the soluble nail. The inner hole of the backing ring is a tapered hole and the diameter of the inner end of the tapered hole is smaller than the diameter of the outer end. The inner end of the sealing ring is located in the conical annulus formed by the tapered hole and the small end of the soluble nail, and the outer end of the sealing ring is located outside the outer end of the backing ring. The nut is tightened on the expanded hole mouth of the liquid outlet channel to compress the sealing ring, so that the outer side of the inner end of the sealing ring is tightly sealed with the tapered hole, and the outer side of the inner end of the sealing ring is tightly sealed with the outer side of the small end of the soluble nail.

[0007] Furthermore, the timed unsealing packer also includes an upper connecting tube, an upper piston, a lower connecting tube, a lower piston and a lower joint. The lower end of the upper connecting tube is sealed and connected to the inner side of the upper end of the lower connecting tube. The inner side of the upper end of the upper piston is sealed and slidably sleeved on the outer side of the middle section of the upper connecting tube. The inner side of the lower section of the upper piston is sealed and slidably sleeved on the outer side of the upper section of the lower connecting tube. The closed annular space between the lower section of the upper piston and the lower section of the upper connecting tube forms a piston chamber. The lower end of the lower connecting tube is sealed and connected to the inner side of the upper end of the lower joint. The inner side of the upper end of the lower piston is sealed and slidably sleeved on the outer side of the middle section of the lower connecting tube. The inner side of the lower section of the lower piston is sealed and slidably sleeved on the outer side of the upper section of the lower joint. The closed annular space between the lower section of the lower piston and the lower section of the lower connecting tube forms a piston chamber.

[0008] Furthermore, the timed unsealing packer also includes an upper joint, a thrust sleeve, a rubber sleeve and a spacer ring. The lower end of the upper joint is sealed and connected to the inner side of the upper end of the upper connecting pipe. The inner side of the upper end of the thrust sleeve can be slidably sleeved on the outer side of the lower section of the upper joint. After the lower end of the thrust sleeve passes over the outer side of the upper end of the upper connecting pipe, it abuts against the upper end of the upper piston. The rubber sleeve and the spacer ring are sleeved outside the middle section of the upper joint and between the upper end step of the upper joint and the upper end of the thrust sleeve. There are multiple rubber sleeves, and the spacer rings are located between adjacent rubber sleeves.

[0009] Furthermore, the thrust sleeve and the upper end of the upper connecting pipe are relatively fixed by a plurality of shear nails.

[0010] Furthermore, the annular space between the upper connecting tube and the thrust sleeve located between the upper end step of the upper connecting tube and the upper end of the upper piston forms a spring chamber, and a thrust spring is provided in the spring chamber, the upper end of the thrust spring is abutted against the lower side of the upper end step of the upper connecting tube, and the lower end of the thrust spring is abutted against the upper end of the upper piston.

[0011] Furthermore, an exhaust hole communicating with the spring chamber is provided on the thrust sleeve.

[0012] Furthermore, a filling hole communicating with the piston cavity is provided outside the upper piston and the lower piston, and a sealing plug coated with anti-loosening adhesive is installed in the filling hole.

[0013] Furthermore, the timed unsealing seal also includes a bursting piece, which is a sheet that is thin in the middle and thick at the edges. The bursting piece is arranged at the bottom of the expanded hole of the liquid inlet channel and is pressed by the inner end of the one-way valve, wherein the liquid flow direction of the one-way valve is from the liquid inlet channel to the piston chamber.

[0014] The present invention has the following advantages:

[0015] During the downhole process, the piston cavity does not enter the wellbore liquid, and the potassium chloride does not dissolve or come into contact with the soluble nail. Therefore, the soluble nail does not dissolve during this period, which means that the unsealing time is not calculated from the start of downhole operation. During the setting process, the water hole is pressurized, and the wellbore liquid enters the piston cavity through the liquid inlet channel. As the pressure increases, the thrust spring is compressed, and the packer is set. During the setting process and before unsealing, the liquid and pressure in the piston cavity are sealed within the cavity by the one-way valve until the soluble nail is completely dissolved. The piston cavity is then connected to the water hole to release the piston cavity pressure. Before this, the rubber sleeve is kept in a state of high pressure compression, thereby maintaining a good seal. After the wellbore liquid enters the piston cavity, the potassium chloride merges with the wellbore liquid, and the dissolved potassium chloride comes into contact with the soluble nail, at which point the soluble nail begins to dissolve, and the setting and unsealing timer begins. When the soluble nail is completely dissolved, the liquid in the piston cavity is discharged back into the water hole to release the pressure. The pressure inside and outside the piston is balanced. Under the action of the rubber sleeve's own elasticity and the thrust spring, the piston returns to its original position, and the packer is automatically unsealed. In this way, the requirements for construction technology and time become more relaxed; since dissolution and unsealing can be achieved without using soluble rubber cartridges, there is no need to lift the pipe string, and there is no problem of insufficient lifting force or drill sticking. At the same time, the rubber cartridges commonly used in sealers can be used, so the technical requirements of sealing high temperature and high pressure can be met. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for the embodiments or the description of the prior art. Obviously, the drawings described below are merely exemplary, and those skilled in the art can, without inventive effort, derive other implementation drawings based on the provided drawings.

[0017] The structures, proportions, sizes, etc. illustrated in this specification are intended solely to complement the contents disclosed herein and to facilitate understanding and reading by persons skilled in the art. They are not intended to limit the conditions under which the present invention may be implemented and therefore have no substantive technical significance. Any structural modifications, changes in proportions, or adjustments in sizes, without affecting the efficacy and objectives of the present invention, shall remain within the scope of the technical contents disclosed herein.

[0018] Figure 1 A schematic structural diagram of a timed release packer provided in an embodiment of the present invention;

[0019] Figure 2 for Figure 1 A magnified view of A in FIG;

[0020] Figure 3 for Figure 1Magnified view of B in .

[0021] In the figure: 1-upper joint, 2-upper connecting pipe, 3-lower connecting pipe, 4-lower joint, 5-rubber cylinder, 6-spacer ring, 7-thrust sleeve, 8-upper piston, 9-lower piston, 10-check valve, 11-timed unsealing mechanism, 12-bursting disc, 13-piston chamber, 14-liquid inlet channel, 15-liquid outlet channel, 16-soluble nail, 17-gasket, 18-sealing ring, 19-nut, 20-plug, 21-shear nail, 22-spring chamber, 23-thrust spring, 24-exhaust hole, 25-water eye. DETAILED DESCRIPTION

[0022] The following describes the implementation of the present invention using specific embodiments. Those skilled in the art will readily understand the other advantages and benefits of the present invention from the disclosure herein. Obviously, the embodiments described are only a portion of the present invention, not all of it. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without inventive effort are intended to fall within the scope of protection of the present invention.

[0023] The terms "upper", "lower", "left", "right", "middle", etc. used in this specification are only for the convenience of description and are not intended to limit the scope of the present invention. Changes or adjustments to their relative relationships should be regarded as within the scope of the present invention without substantially changing the technical content.

[0024] like Figures 1 to 3 As shown, this embodiment provides a timed unsealing packer, which includes the upper joint 1, upper connecting pipe 2, lower connecting pipe 3, lower joint 4, rubber cylinder 5, spacer ring 6, thrust sleeve 7, upper piston 8 and lower piston 9 in the prior art, and also includes a newly added one-way valve 10, timed unsealing mechanism 11, bursting disc 12, and partial changes are made to the upper connecting pipe 2, lower connecting pipe 3, upper piston 8 and lower piston 9.

[0025] The lower end of the upper connector 1 is threadedly connected to the inner side of the upper end of the upper connecting tube 2 and sealed with a sealing ring. The inner side of the upper end of the thrust sleeve 7 slidably fits over the outer side of the lower section of the upper connector 1. The lower end of the thrust sleeve 7 passes over the outer side of the upper end of the upper connecting tube 2 and abuts against the upper end of the upper piston 8. A rubber sleeve 5 and a spacer ring 6 are mounted outside the middle section of the upper connector 1, between the upper step of the upper connector 1 and the upper end of the thrust sleeve 7. Multiple rubber sleeves 5 are provided, and spacer rings 6 are located between adjacent rubber sleeves 5. The lower end of the upper connecting tube 2 is threadedly connected to the inner side of the upper end of the lower connecting tube 3 and sealed with a sealing ring. The inner side of the upper end of the upper piston 8 slidably fits over the outer side of the middle section of the upper connecting tube 2 and is sealed with a sealing ring. The inner side of the lower section of the upper piston 8 slidably fits over the outer side of the upper section of the lower connecting tube 3 and is sealed with a sealing ring. The closed annulus between the lower section of the upper piston 8 and the lower section of the upper connecting tube 2 forms the piston chamber 13. The lower end of the lower connecting tube 3 is threadedly connected to the inner side of the upper end of the lower joint 4 and sealed with a sealing ring. The inner side of the upper end of the lower piston 9 slidably fits over the outer side of the middle section of the lower connecting tube 3 and is sealed with a sealing ring. The inner side of the lower section of the lower piston 9 slidably fits over the outer side of the upper section of the lower joint 4 and is sealed with a sealing ring. The closed annular space between the lower section of the lower piston 9 and the lower section of the lower connecting tube 3 forms a piston chamber 13.

[0026] Generally, a liquid inlet channel 14 is provided between the piston chamber 13 and the water hole 25. In this embodiment, there are two piston chambers 13, and therefore there are two liquid inlet channels 14. Specifically, a transverse blind hole is provided on the inner side of the upper end of the lower piston 9, and a vertical blind hole is provided on the upper side of the upper end of the lower piston 9. The inner ends of the two blind holes are connected to form an L-shaped through hole. The transverse through hole of the upper connecting pipe 2 is aligned with the transverse blind hole of the lower piston 9, thereby forming a liquid inlet channel 14. Similarly, a transverse blind hole is provided on the inner side of the upper end of the lower joint 4, and a vertical blind hole is provided on the upper side of the upper end of the lower joint 4. The inner ends of the two blind holes are connected to form an L-shaped through hole. The transverse through hole of the lower connecting pipe 3 is aligned with the transverse blind hole of the lower joint 4, thereby forming another liquid inlet channel 14.

[0027] A liquid outlet passage 15 is also provided between the piston chamber 13 and the water eye 25. In the present embodiment, there are two piston chambers 13, so there are also two liquid outlet passages 15. Specifically, a platform is milled on the outer side of the upper end of the lower connecting tube 3, and the platform is staggered with the liquid inlet channel 14 in the circumferential direction. A three-level stepped hole with a larger outer side and a smaller inner side is drilled on the platform toward the direction of the rotation axis. The outer hole is used to screw on the nut 19, the middle hole is used to install the soluble nail 16 and the gasket 17, and the inner hole is used to connect to another transverse through hole of the upper connecting tube 2. After the three-level stepped hole is connected to the transverse through hole, a liquid outlet channel 15 is formed; similarly, a platform is milled on the outer side of the upper end of the lower joint 4, and the platform is staggered with the liquid inlet channel 14 in the circumferential direction. A three-level stepped hole with a larger outer side and a smaller inner side is drilled on the platform toward the direction of the rotation axis. The outer hole is used to screw on the nut 19, the middle hole is used to install the soluble nail 16 and the gasket 17, and the inner hole is used to connect to another transverse through hole of the lower connecting tube 3. After the three-level stepped hole is connected to the transverse through hole, another liquid outlet channel 15 is formed.

[0028] A one-way valve 10 is disposed within the piston cavity 13 and mounted within the expanded bore of the liquid inlet passage 14 within the piston cavity 13. This expanded bore can be a two-stage stepped bore. The inner end of the one-way valve 10 screws into the outer bore. Existing one-way valve 10 can be used. Liquid flows from the liquid inlet passage 14 to the piston cavity 13. A bursting disc 12 is mounted within the inner bore. The inner end of the one-way valve 10 presses against the inner end of the one-way valve 10, creating a seal between the inner bore and the bursting disc 12, thereby blocking the liquid inlet passage 14. The bursting disc 12 is a thin sheet with thicker edges. When subjected to a certain pressure, the thinner portion in the middle breaks or cracks, thereby opening the liquid inlet passage 14.

[0029] The timed unsealing mechanism 11 includes a soluble nail 16, a backing ring 17, a sealing ring 18, and a pressing nut 19. The soluble nail 16 is T-shaped, i.e., it has a large and small end. The large end is a circular disc and the small end is a cylinder. The large end is arranged inward in the middle hole of the liquid outlet channel 15, and the large end abuts on the step between the middle hole and the inner hole, while the small end is arranged toward the outer hole. The outer circumference of the backing ring 17 is adapted to the middle hole. The backing ring 17 is sleeved on the small end of the soluble nail 16. The sum of the height of the backing ring 17 and the thickness of the large end of the soluble nail 16 is equal to the depth of the middle hole. The inner hole of the backing ring 17 is a tapered hole, and the diameter of the inner end of the tapered hole is smaller than the diameter of the outer end. The inner end of the sealing ring 18 is located in the conical annulus formed by the tapered hole and the small end of the soluble nail 16. The outer end of the sealing ring 18 is located outside the outer end of the backing ring 17 and covers the step between the outer hole and the middle hole. The pressure nut 19 is screwed onto the outer hole of the liquid outlet channel 15. During the tightening process, the sealing ring 18 is pushed inward a little distance and pressed. On the one hand, the outer side of the inner end of the sealing ring 18 is tightly sealed with the tapered hole, and on the other hand, the outer side of the inner end of the sealing ring 18 is tightly sealed with the outer side of the small end of the soluble nail 16. In this way, during the process of the soluble nail 16 contacting the potassium chloride solution to dissolve, the remaining soluble nail 16 and the sealing ring 18 can also be kept sealed at all times. In this way, the soluble nail 16 can be dissolved at a uniform speed, which is conducive to controlling the entire dissolution time. The pressure nut 19 is a nut with an inner hexagonal or inner square corners, and has a channel to ensure the inlet and outlet of liquid.

[0030] Potassium chloride is placed in the piston cavity 13. Potassium chloride is generally placed outside the packer in the form of a potassium chloride bag and added to the piston cavity 13 when preparing to go down the well. Therefore, a packing hole connected to the piston cavity 13 is provided on the outside of the upper piston 8 and the lower piston 9. A plug 20 is installed in the packing hole, and a sealing ring is used to seal the inner end of the plug 20 and the packing hole. Before potassium chloride is added, the plug 20 is not installed in the packing hole. Before installation, the plug 20 is coated with anti-loosening glue (on the thread of the plug 20 or the packing hole) to achieve a two-stage seal (soft seal of the sealing ring + hard seal of the glue).

[0031] Generally, the thrust sleeve 7 is relatively fixed to the upper end of the upper connecting pipe 2 by a plurality of shear nails 21. This ensures that during the process of going down into the well, the thrust sleeve 7 does not upwardly squeeze the rubber sleeve 5 due to friction with the well wall, resulting in premature sealing.

[0032] The annulus between the upper connecting tube 2 and the thrust sleeve 7, located between the upper end step of the upper connecting tube 2 and the upper end of the upper piston 8, forms a spring chamber 22. A thrust spring 23 is disposed within the spring chamber 22. The upper end of the thrust spring 23 abuts against the lower side of the upper end step of the upper connecting tube 2, while the lower end of the thrust spring 23 abuts against the upper end of the upper piston 8. When the soluble nail 16 dissolves, the high-pressure liquid sealed within the piston chamber 13 flows from the liquid outlet channel 15 into the water eye 25, releasing the upward thrust on the rubber sleeve 5. The rubber sleeve 5 returns to its original shape under its own elasticity, thereby unsealing. However, during this process, the friction of the piston is relatively large, which may affect the recovery of the rubber sleeve 5. With the thrust spring 23, when unsealing, the thrust spring 23 pushes the piston downward, thereby reducing the resistance to the recovery of the rubber sleeve 5.

[0033] When the seal is set, the piston moves upward, making the space of the spring chamber 22 smaller. At this time, there is a possibility of compressed air. Therefore, an exhaust hole 24 connected to the spring chamber 22 is provided on the thrust sleeve 7 to discharge the internal air, reduce the upward resistance of the piston, and increase the thrust when the seal is set.

[0034] During assembly, check the flexibility of the one-way valve 10 to ensure that it can be used normally.

[0035] Before going down the well, potassium chloride is added into the piston cavity 13 and then the plug 20 is installed.

[0036] After going down the well, the water eye 25 is pressurized to increase the pressure of the liquid in the well to a certain degree. At this time, the bursting disc 12 is crushed, the liquid inlet channel 14 is opened, and the liquid in the well passes through the liquid inlet channel 14 and pushes open the one-way valve 10 to enter the piston chamber 13; continue to pressurize the water eye 25, and the piston has a certain upward force under the action of the water pressure. When the upward force is greater than the shearing force of the shear nail 21, the shear nail 21 is sheared, and the upward force is released instantly. The piston pushes the thrust sleeve 7 upward, and the rubber cylinder 5 is compressed and shortened in height (the width of the traffic), but expands outward on the circumference. When the outer periphery of the rubber cylinder 5 is against the well wall (or the inner wall of the casing) and has sufficient pressure, the seat seal is completed. At this time, the high-pressure liquid in the piston chamber 13 cannot flow back to the water eye 25 from the liquid inlet channel 14 and the liquid outlet channel 15 (the liquid inlet channel 14 is The one-way valve 10 is sealed, and the liquid outlet channel 15 is sealed by the soluble nail 16); when the liquid in the well enters the piston chamber 13, potassium chloride dissolves in the liquid in the well to form a potassium chloride solution, and the potassium chloride solution contacts the cylinder of the soluble nail 16, and the cylinder slowly dissolves (the dissolution process is much longer than the sealing process, but not so long compared to the downhole process, so it can be said that the unsealing is timed from the sealing process); when the soluble nail 16 is completely dissolved, the liquid outlet channel 15 connects the water eye 25 and the piston chamber 13, and the high-pressure liquid sealed in the piston chamber 13 flows back to the water eye 25. After the pressure is released, the rubber cylinder 5 recovers under its own elasticity, and the piston moves downward under the action of the thrust spring 23. After a period of time, the outer periphery of the rubber cylinder 5 shrinks to a certain extent, and the unsealing is completed. The tubing string can be lifted up to take out the entire tubing string and tool string.

[0037] The dissolution time of the soluble nail 16 can be controlled by: 1. Controlling the concentration of the solute in the solution (i.e., the relationship between the size of the piston chamber 13 and the amount of potassium chloride); 2. Controlling the length of the soluble nail 16; and 3. Controlling the material ratio of the soluble nail 16. The soluble nail 16 is generally made of a magnesium-aluminum alloy, such as that used in soluble slips or soluble bridge plugs: 25-80% magnesium, the balance being aluminum and impurities with a content of less than or equal to 1%. The dissolution time of the soluble nail 16 can be determined through ground testing. The appropriate soluble nail 16 (length and formulation, both commercially available) and the appropriate amount of potassium chloride (if the piston chamber 13 capacity is fixed) are selected as needed.

[0038] The timed unsealing packer provided in this embodiment does not allow the piston chamber 13 to enter the wellbore liquid during the downhole process, and the potassium chloride does not dissolve or come into contact with the soluble nail 16. Therefore, the soluble nail 16 does not dissolve during this period, that is, the unsealing time is not calculated from the start of downhole. During the sealing process, the water hole 25 is pressurized, and the wellbore liquid enters the piston chamber 13 from the liquid inlet channel 14. As the pressure increases, the thrust spring 23 is compressed, and the packer is sealed. During the sealing process and before unsealing, the liquid and pressure in the piston chamber 13 are sealed in the cavity by the one-way valve 10 until the soluble nail 16 is completely dissolved. The piston chamber 13 is then connected to the water hole 25 to release the pressure in the piston chamber 13. Before this, it can be ensured that the rubber cylinder 5 is always in a state of being compressed by high pressure, thereby maintaining a good seal of the rubber cylinder 5. When the liquid in the well enters the piston chamber 13, the piston chamber 13 is connected to the water hole 25 to release the pressure in the piston chamber 13. After the packer is filled, the potassium chloride merges with the liquid in the well, and the dissolved potassium chloride comes into contact with the soluble nail 16, at which point the soluble nail 16 begins to dissolve, i.e., the unsealing timer begins after the sealing begins. When the soluble nail 16 is completely dissolved, the liquid in the piston chamber 13 is discharged back into the water hole 25 to complete the pressure relief. The pressure inside and outside the piston is balanced. Under the action of the elasticity of the rubber cylinder 5 itself and the thrust spring 23, the piston resets and the packer is automatically unsealed. The one-way valve 10 is used to seal the high-pressure liquid in the piston chamber 13, forming a non-mechanical lock. The incompressible nature of the liquid is utilized, allowing the packer to independently withstand upward or downward pressure without the need for internal pressure (ordinary unanchored packers cannot withstand upward pressure differences without internal pressure). The use of a two-stage piston can reduce the sealing force of the packer (the pressure of the liquid pressurized in the water hole). The fixed string multi-layer fracturing technology can effectively prevent oil layer contamination, reduce operation time, reduce costs, and improve efficiency. Due to the characteristics of timed release of the packer, more packers can be used to construct more oil layers in one trip of the tubing string, and are no longer limited by the release force of the packer. This not only reduces the operational risk, but also improves the operating environment, which is of great significance to the development of oil and gas fields.

[0039] Although the present invention has been described in detail above using general descriptions and specific embodiments, it will be apparent to those skilled in the art that modifications and improvements may be made thereto. Therefore, such modifications and improvements, without departing from the spirit of the present invention, are intended to be within the scope of protection claimed herein.

Claims

1. A timed unsealing packer, comprising a piston chamber, a liquid inlet passage between the piston chamber and the water hole, characterized in that: The timed unsealing packer also includes a one-way valve and a timed unsealing mechanism. A liquid outlet channel is also provided between the piston chamber and the water eye. Potassium chloride is placed in the piston chamber. The one-way valve is arranged in the piston chamber and installed in the expanded hole of the liquid inlet channel located in the piston chamber. The timed unsealing mechanism includes a soluble nail, a gasket, a sealing ring and a pressing nut. The soluble nail is T-shaped and its large end is facing inward and is arranged in the expanded hole of the liquid outlet channel located in the piston chamber. The gasket is sleeved on the outside of the small end of the soluble nail. The inner hole of the gasket is a tapered hole and the diameter of the inner end of the tapered hole is smaller than the diameter of the outer end. The inner end of the sealing ring is located in the tapered annulus formed by the tapered hole and the small end of the soluble nail. The outer end of the sealing ring is located outside the outer end of the gasket. The pressing nut is tightened on the expanded hole of the liquid outlet channel to compress the sealing ring, so that the outer side of the inner end of the sealing ring is tightly sealed with the tapered hole, and the outer side of the inner end of the sealing ring is tightly sealed with the outer side of the small end of the soluble nail. The timed unsealing packer also includes an upper connecting pipe, an upper piston, a lower connecting pipe, a lower piston and a lower joint, the lower end of the upper connecting pipe is sealedly connected to the inner side of the upper end of the lower connecting pipe, the inner side of the upper end of the upper piston is sealed and slidably sleeved on the outer side of the middle section of the upper connecting pipe, the inner side of the lower section of the upper piston is sealed and slidably sleeved on the outer side of the upper section of the lower connecting pipe, the closed annular space between the lower section of the upper piston and the lower section of the upper connecting pipe forms a piston chamber, the lower end of the lower connecting pipe is sealedly connected to the inner side of the upper end of the lower joint, the upper end of the lower piston is sealed and slidably sleeved on the outer side of the middle section of the lower connecting pipe, the inner side of the lower section of the lower piston is sealed and slidably sleeved on the outer side of the upper section of the lower joint, and the closed annular space between the lower section of the lower piston and the lower section of the lower connecting pipe forms a piston chamber; The timed release sealer also includes a bursting disc, which is a sheet of material that is thin in the middle and thick at the edges. The bursting disc is arranged at the bottom of the expanded hole of the liquid inlet channel and is pressed by the inner end of the one-way valve, wherein the liquid flow direction of the one-way valve is from the liquid inlet channel to the piston chamber.

2. The timed release packer according to claim 1, characterized in that: The timed unsealing packer also includes an upper joint, a thrust sleeve, a rubber sleeve and a spacer ring. The lower end of the upper joint is sealed with the inner side of the upper end of the upper connecting pipe. The inner side of the upper end of the thrust sleeve can be slidably sleeved on the outer side of the lower section of the upper joint. The lower end of the thrust sleeve is sleeved over the outer side of the upper end of the upper connecting pipe and abuts against the upper end of the upper piston. The rubber sleeve and the spacer ring are sleeved outside the middle section of the upper joint and between the upper end step of the upper joint and the upper end of the thrust sleeve. There are multiple rubber sleeves, and the spacer ring is located between adjacent rubber sleeves.

3. The timed release packer according to claim 2, characterized in that: The thrust sleeve and the upper end of the upper connecting pipe are relatively fixed via a plurality of shear nails.

4. The timed release packer according to claim 2, characterized in that: The annular space between the upper connecting tube and the thrust sleeve, located between the upper end step of the upper connecting tube and the upper end of the upper piston, forms a spring chamber, in which a thrust spring is provided. The upper end of the thrust spring abuts against the lower side of the upper end step of the upper connecting tube, and the lower end of the thrust spring abuts against the upper end of the upper piston.

5. The timed release packer according to claim 4, characterized in that: The thrust sleeve is provided with an exhaust hole communicating with the spring cavity.

6. The timed release packer according to claim 1, characterized in that: A filling hole communicating with the piston cavity is provided outside the upper piston and the lower piston, and a sealing plug coated with anti-loosening adhesive is installed in the filling hole.

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