Hydraulic self-sealing packer capable of being used for composite coiled tubing

Abstract

The invention relates to the technical field of downhole tools, in particular to a hydraulic self-sealing packer capable of being used for a composite coiled tubing. Comprising an upper connector, an overflowing pipe and an inner central pipe, the upper connector is fixedly connected with an upper connecting sleeve through an upper deblocking shear pin, the upper connecting sleeve is in threaded sealing connection with an outer central pipe, the outer central pipe below the upper connecting sleeve is sleeved with a packing assembly, the outer central pipe below a locking ring is sleeved with a limiting sleeve, and the lower end of a lower connecting sleeve is in threaded connection with a cone. A lower central pipe is fixedly and hermetically connected in the lower end of the outer central pipe, an inner sleeve sleeves the outer side of the lower central pipe, the upper end of the inner sleeve is fixedly connected with the lower end of the cone, a slip bowl sleeves the outer side of the inner sleeve, a plurality of slips are uniformly distributed and connected on the circumference of the upper end of the slip bowl, and the slip bowl is fixedly connected with a hydraulic outer cylinder through a setting shear pin; a multi-stage hydraulic cylinder is arranged between the hydraulic outer barrel and the inner central pipe, and the lower end of the hydraulic outer barrel is fixedly connected with a lower connector. The packer is reliable in setting and convenient to unset.

Description

Technical Field

[0001] The invention relates to the technical field of downhole tools, and in particular to a hydraulic self-sealing packer that can be used for a composite continuous oil pipe. Background Art

[0002] Oil well water injection is an effective measure to supplement the bottom layer energy and improve the recovery rate during the development of oil fields. In addition, with the rapid development of water injection technology, a new and convenient water injection method has emerged. The cable-laid pipe intelligent water injection system uses cable-laid pipes (pre-installed cable composite continuous oil pipes or composite continuous oil pipes with multiple channels in the center) to replace conventional metal oil pipes. There is no need to tie cables to the outside of the oil pipes and install cable guards. The construction is convenient and efficient. There is no risk of cable corrosion and collision when the cables are built in, and the sealing is reliable. The use of non-metallic composite materials makes it difficult for the pipe wall to scale, and it has stronger corrosion resistance than metal oil pipes.

[0003] However, composite coiled tubing has certain disadvantages. Its compressive and tensile strengths are weaker than those of traditional metal tubing. Traditional water injection packers are generally tested by pressure setting to isolate the oil layer. The setting pressure is relatively high and is not suitable for the new composite coiled tubing.

[0004] In view of this, the present invention is proposed. When the packer is put into the well for use, it only needs to be lowered into the preset position to be self-sealed. The self-sealing is reliable and the unsealing is convenient, and the present invention can be applied to the composite coiled tubing. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a hydraulic self-sealing packer which is reliable in self-sealing and convenient in unsealing and can be applied to composite continuous oil pipes.

[0006] In order to achieve the above object, the technical solution provided by the present invention is:

[0007] A hydraulic self-sealing packer that can be used for composite continuous oil pipe comprises an upper joint, wherein the upper joint is fixedly and sealedly connected to a flow pipe, the lower end of the upper joint is sealedly connected to an upper connecting sleeve and an inner center pipe, the flow pipe is located in the inner center pipe, the inner center pipe is fixedly connected to the upper joint, the upper joint and the upper connecting sleeve are fixedly connected by upper unsealing shear nails, the upper connecting sleeve is threadedly and sealedly connected to an outer center pipe, the outer center pipe upper sleeve below the upper connecting sleeve is provided with a packing assembly, the lower connecting sleeve is arranged on the outer center pipe, the inner sleeve of the annular groove of the outer center pipe is provided with a locking ring, the outer center pipe upper sleeve below the locking ring is provided with a limiting sleeve, the limiting sleeve is fixed to the outer center pipe by lower unsealing shear nails, the limiting sleeve limits the downward movement of the locking ring, the lower end of the lower connecting sleeve is threadedly connected to a cone, the inner edge of the upper end of the cone is processed with teeth for engaging with the locking ring, the lower end of the outer center pipe is fixedly and sealedly connected to the lower center pipe, and the lower center pipe penetrates The cone is penetrated, and an inner sleeve is provided on the outer side of the lower center tube. The upper end of the inner sleeve is fixedly connected to the lower end of the cone. A slip seat is provided on the outer side of the inner sleeve. A plurality of slips are evenly distributed on the circumference of the upper end of the slip seat. The slips are in contact with the conical surface of the cone. The slip seat is fixedly connected to a hydraulic outer cylinder through sealing shear nails. A spring seat is slidably connected between the hydraulic outer cylinder and the inner sleeve. The spring seat and the slip seat are connected through an inner spring. A multi-stage hydraulic cylinder is arranged between the hydraulic outer cylinder and the inner center tube. The fixed part of the multi-stage hydraulic cylinder is fixedly connected to the lower center tube. The telescopic end of the multi-stage hydraulic cylinder can push the spring seat upward. A lower joint is fixedly connected to the lower end of the hydraulic outer cylinder. The lower end of the inner center tube is fixedly and sealedly connected to the lower joint. The lower end of the flow pipe is fixedly and sealedly connected to the lower joint. A liquid inlet channel is opened on the lower joint. The liquid inlet channel is connected to the lower liquid inlet end of the multi-stage hydraulic cylinder. A soluble plug is sealedly connected to the inner thread of the lower end of the liquid inlet channel.

[0008] Specifically, the upper end of the packing assembly is tightly against the lower end of the upper connecting sleeve, a step is processed on the outer center pipe below the packing assembly, the lower connecting sleeve is located on the step of the outer center pipe, and the upper end of the lower connecting sleeve is tightly against the lower end of the packing assembly.

[0009] Specifically, the sealing assembly includes a plurality of rubber tubes sleeved on the outside of the outer central tube, and a spacer ring is arranged between two adjacent rubber tubes.

[0010] Specifically, the lower end of the slip is installed in a dovetail groove on the slip seat.

[0011] The cam is connected with the lower end of the piston rod, and the cam is connected with the piston rod at the bottom end of the piston rod, and the cam is connected with the piston rod at the bottom end of the piston rod.

[0012] Specifically, a first balance pressure hole is provided on the upper piston inner cylinder, and the first balance pressure hole is connected to the gap between the upper piston inner cylinder and the inner center tube; a first inlet hole corresponding to the middle piston push cylinder is provided on the hydraulic outer cylinder, a third inlet hole is provided on the middle piston push cylinder above the first inlet hole, the third inlet hole is sealed and blocked by the upper end of the middle piston inner cylinder, a second balance pressure hole is provided on the middle piston inner cylinder below the third inlet hole, and the second balance pressure hole is connected to the gap between the middle piston inner cylinder and the inner center tube; a second inlet hole corresponding to the lower piston push cylinder is provided on the hydraulic outer cylinder, a fourth inlet hole is provided on the lower piston push cylinder above the second inlet hole, the fourth inlet hole is sealed and blocked by the upper end of the lower piston inner cylinder, a third balance pressure hole is provided on the lower piston inner cylinder below the fourth inlet hole, and the third balance pressure hole is connected to the gap between the lower piston inner cylinder and the inner center tube.

[0013] Specifically, an annular flange is processed on the outer edge of the inner center tube on the inner side of the upper end of the upper piston inner cylinder, and the flange is in sealing contact with the sealing ring on the inner side of the upper end of the upper piston inner cylinder.

[0014] Specifically, a limiting groove is provided on the outer side of the lower center tube, a ball groove corresponding to the limiting groove is provided on the inner sleeve, a steel ball is installed in the ball groove, the inner part of the steel ball is located in the limiting groove, the outer part of the steel ball contacts the inner edge of the upper part of the spring seat, an annular cavity is provided in the lower part of the spring seat, and after the elastic seat moves upward and the annular cavity corresponds to the ball groove, the outer part of the steel ball can enter the annular cavity, and after the outer part of the steel ball enters the annular cavity, the inner sleeve can move upward relative to the lower center tube.

[0015] Specifically, the upper end of the soluble plug is sealed and connected to the lower joint through a sealing ring, and a slit is processed on the lower joint on one side of the soluble plug, and the well fluid can contact the soluble plug through the slit.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] 1. The packer is reliable in setting and easy to release. The third and fourth inlets are blocked before setting to prevent the well fluid from entering the multi-stage hydraulic cylinder during the well entry process to generate thrust shearing the setting shear pins.

[0018] 2. When unsealing, after the flange on the inner center tube is misaligned with the sealing ring, the well fluid in the casing can pass through the gap between the inner center tube and the outer center tube, the gap between the lower center tube and the inner center tube, the gap between the upper piston inner tube and the inner center tube, and the first balanced pressure hole to enter between the upper end of the upper piston inner tube and the middle piston push tube. The well fluid in the casing can pass through the gap between the inner center tube and the middle piston inner tube and the second balanced pressure hole to enter between the upper end of the middle piston inner tube and the upper end of the lower piston push tube. The well fluid in the casing can also pass through the gap between the inner center tube and the lower piston inner tube through the third balanced pressure hole to enter between the upper end of the lower piston inner tube and the starting piston. The pressure inside the multi-stage hydraulic cylinder can be balanced with the pressure inside the casing, which is convenient for unsealing operations.

[0019] 3. Since the middle diameter of the packer is large, the internal flow passage can meet the needs of multiple flow passages of the composite coiled tubing, thereby meeting the needs of simultaneous stratified water injection. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a schematic diagram of the packer.

[0021] Figure 2 for Figure 1 Magnified view of area A.

[0022] Figure 3 for Figure 1 Magnified view of area B.

[0023] The names of the parts in the attached drawings are: 1. First inlet hole, 2. Second inlet hole, 3. Flange, 4. Sealing ring, 5. Lower joint, 6. Upper joint, 7. Flow tube, 8. Upper unsealing shear nail, 9. Inner center tube, 101. Outer center tube, 102. Upper connecting sleeve, 103. Rubber cylinder, 104. Spacer ring, 105. Lower connecting sleeve, 201. Lower center tube, 202. Locking ring, 203. Limiting sleeve, 204. Lower unsealing shear nail, 205. Cone, 206. Slip, 207. Inner sleeve, 208. Slip seat, 209. Setting shear nail, 210. Inner spring, 211. Steel ball, 212, spring seat, 213, limit groove, 214, annular cavity, 301, upper piston push cylinder, 302, upper piston inner cylinder, 3021, first balance pressure hole, 303, hydraulic outer cylinder, 304, middle piston push cylinder, 3041, third inlet hole, 305, middle piston inner cylinder, 3051, second balance pressure hole, 306, lower piston push cylinder, 3061, fourth inlet hole, 307, lower piston inner cylinder, 3071, third balance pressure hole, 308, starting piston, 401, sealing ring, 402, soluble plug, 403, slit, 404, liquid inlet channel. DETAILED DESCRIPTION

[0024] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0025] Embodiment 1: Figure 1-Figure 3 As shown, a hydraulic self-sealing packer that can be used for composite coiled tubing includes an upper joint 6, and a flow pipe 7 is fixedly and sealedly connected inside the upper joint 6. The lower end of the upper joint 6 is sealedly connected with an upper connecting sleeve 102 and an inner center pipe 9, the flow pipe 7 is located inside the inner center pipe 9, the inner center pipe 9 is fixedly connected to the upper joint 6, and the upper joint 6 is fixedly connected to the upper connecting sleeve 102 through an upper unsealing shear nail 8.

[0026] The upper connecting sleeve 102 is sealed with the outer central tube 101 through the internal thread, a packing assembly is sleeved on the outer central tube 101 below the upper connecting sleeve 102, and a lower connecting sleeve 105 is sleeved on the outer central tube 101. Specifically, the upper end of the packing assembly is tightly against the lower end of the upper connecting sleeve 102, a step is processed on the outer central tube 101 below the packing assembly, the lower connecting sleeve 105 is seated on the step of the outer central tube 101, and the upper end of the lower connecting sleeve 105 is tightly against the lower end of the packing assembly. The packing assembly includes a plurality of rubber sleeves 103 sleeved on the outside of the outer central tube 101, and a spacer ring 104 is arranged between two adjacent rubber sleeves 103.

[0027] A locking ring 202 is sleeved in the annular groove of the outer central tube 101, and a limiting sleeve 203 is sleeved on the outer central tube 101 below the locking ring 202. The limiting sleeve 203 is fixed to the outer central tube 101 by lower unsealing shear pins 204, and the limiting sleeve 203 limits the locking ring 202 from moving downward.

[0028] The lower end of the lower connecting sleeve 105 is threadedly connected to a cone 205, and the inner edge of the upper end of the cone 205 is processed with teeth for engaging with the lock ring 202. The lower end of the outer center tube 101 is fixedly and sealedly connected to the lower center tube 201, and the lower center tube 201 passes through the cone 205. The outer side of the lower center tube 201 is sleeved with an inner sleeve 207, and the upper end of the inner sleeve 207 is fixedly connected to the lower end of the cone 205. The outer side of the inner sleeve 207 is sleeved with a slip seat 208, and the upper end of the slip seat 208 is evenly connected to a plurality of slips 206, and the slips 206 are in contact with the conical surface of the cone 205. Specifically, the lower end of the slip 206 is installed in the dovetail groove on the slip seat 208.

[0029] The slip seat 208 is fixedly connected to the hydraulic outer cylinder 303 through the setting shear pins 209 , a spring seat 212 is slidably connected between the hydraulic outer cylinder 303 and the inner sleeve 207 , and the spring seat 212 is connected to the slip seat 208 through the inner spring 210 .

[0030] A multi-stage hydraulic cylinder is arranged between the hydraulic outer cylinder 303 and the inner center tube 9. The fixed part of the multi-stage hydraulic cylinder is fixedly connected to the lower center tube 201. The telescopic end of the multi-stage hydraulic cylinder can push the spring seat 212 upward.

[0031] The lower end of the hydraulic outer cylinder 303 is fixedly connected with a lower joint 5 , the lower end of the inner center tube 9 is fixedly and sealedly connected to the lower joint 5 , and the lower end of the flow tube 7 is fixedly and sealedly connected to the lower joint 5 .

[0032] The lower joint 5 is provided with a liquid inlet channel 404, which is connected to the lower liquid inlet end of the multi-stage hydraulic cylinder, and the lower end of the liquid inlet channel 404 is internally threaded and sealed with a soluble plug 402. Specifically, the upper end of the soluble plug 402 is sealed and connected to the lower joint 5 through a sealing ring 401, and a slit 403 is processed on the lower joint 5 on one side of the soluble plug 402, and the well fluid can contact the soluble plug 402 through the slit 403.

[0033] The multi-stage hydraulic cylinder includes an upper piston inner cylinder 302, the upper end of the upper piston inner cylinder 302 is fixedly connected to the lower end of the lower center tube 201, the lower end of the upper piston inner cylinder 302 is fixedly and sealedly connected to the middle piston inner cylinder 305, the lower end of the middle piston inner cylinder 305 is fixedly and sealedly connected to the lower piston inner cylinder 307, the lower end of the lower piston inner cylinder 307 is slidably and sealedly connected to the lower joint 5, an upper piston push cylinder 301 is arranged on the outer side of the upper piston inner cylinder 302, the upper end of the upper piston push cylinder 301 is tightly against the lower end of the spring seat 212, the upper end of the upper piston inner cylinder 302 is slidably and sealedly connected to the inner side of the upper piston push cylinder 301, and the lower end of the upper piston push cylinder 301 is fixedly and sealedly connected to the middle The piston push cylinder 304, the inner side of the upper end of the middle piston push cylinder 304 is slidingly and sealedly connected to the outer side of the upper piston inner cylinder 302, the outer side of the upper end of the middle piston inner cylinder 305 is slidingly and sealedly connected to the inner side of the middle piston push cylinder 304, the lower end of the middle piston push cylinder 304 is fixedly and sealedly connected to the lower piston push cylinder 306, the inner side of the upper end of the lower piston push cylinder 306 is slidingly and sealedly connected to the outer side of the middle piston inner cylinder 305, the outer side of the upper end of the lower piston inner cylinder 307 is slidingly and sealedly connected to the inner side of the lower piston push cylinder 306, the lower end of the lower piston push cylinder 306 is fixedly and sealedly connected to the starting piston 308, and the inner side of the starting piston 308 is slidingly and sealedly connected to the outer side of the lower piston inner cylinder 307.

[0034] The upper piston inner cylinder 302 is provided with a first balanced pressure hole 3021, which is in communication with the gap between the upper piston inner cylinder 302 and the inner center tube 9. The hydraulic outer cylinder 303 is provided with a first inlet hole 1 corresponding to the middle piston push cylinder 304, a third inlet hole 3041 is provided on the middle piston push cylinder 304 above the first inlet hole 1, the third inlet hole 3041 is sealed and blocked by the upper end of the middle piston inner cylinder 305, and a second balanced pressure hole 3051 is provided on the middle piston inner cylinder 305 below the third inlet hole 3041, which is in communication with the gap between the middle piston inner cylinder 305 and the inner center tube 9. A second inlet hole 2 corresponding to the lower piston push cylinder 306 is formed on the hydraulic outer cylinder 303, a fourth inlet hole 3061 is formed on the lower piston push cylinder 306 above the second inlet hole 2, the fourth inlet hole 3061 is sealed and blocked by the upper end of the lower piston inner cylinder 307, a third balance pressure hole 3071 is formed on the lower piston inner cylinder 307 below the fourth inlet hole 3061, and the third balance pressure hole 3071 is connected to the gap between the lower piston inner cylinder 307 and the inner center tube 9.

[0035] An annular flange 3 is processed on the outer edge of the inner center tube 9 on the inner side of the upper end of the upper piston inner tube 302 , and the flange 3 is in sealing contact with the sealing ring 4 on the inner side of the upper end of the upper piston inner tube 302 .

[0036] The lower central tube 201 has a limit groove 213 on the outside, and the inner sleeve 207 has a ball groove corresponding to the limit groove 213. A steel ball 211 is installed in the ball groove. The inner part of the steel ball 211 is located in the limit groove 213, and the outer part of the steel ball 211 contacts the inner edge of the upper part of the spring seat 212. An annular cavity 214 is provided in the lower part of the spring seat 212. After the elastic seat moves upward and the annular cavity 214 corresponds to the ball groove, the outer part of the steel ball 211 can enter the annular cavity 214. After the outer part of the steel ball 211 enters the annular cavity 214, the inner sleeve 207 can move upward relative to the lower central tube 201.

[0037] The upper joint 6 of the packer is connected to the coiled tubing to form a water injection string, and the packer is lowered to the designed depth through the coiled tubing.

[0038] The well fluid in the casing contacts the soluble plug 402 through the slit 403. After a certain period of time, the soluble plug 402 dissolves, and the well fluid in the casing enters between the hydraulic outer cylinder 303 and the lower piston inner cylinder 307 below the starting piston 308 through the liquid inlet channel 404. The well fluid can push the starting piston 308, the lower piston push cylinder 306, the middle piston push cylinder 304 and the upper piston push cylinder 301 upward. After the starting piston 308, the lower piston push cylinder 306, the middle piston push cylinder 304 and the upper piston push cylinder 301 move upward, the fourth inlet hole 3061 is misaligned with the upper end of the lower piston inner cylinder 307, and the third inlet hole 3041 is misaligned with the upper end of the middle piston inner cylinder 305. The well fluid in the casing can pass through the first inlet hole 1, the gap between the hydraulic outer cylinder 303 and the middle piston push cylinder 304, and the third inlet hole 3041 into the space between the upper end of the middle piston push cylinder 304 and the middle piston inner cylinder 305. The well fluid in the casing can enter the space between the upper end of the lower piston push cylinder 306 and the lower piston inner cylinder 307 through the second inlet hole 2, the gap between the hydraulic outer cylinder 303 and the lower piston push cylinder 306, and the fourth inlet hole 3061. Since the third inlet hole 3041 and the fourth inlet hole 3061 are blocked before setting, the well fluid is prevented from entering the multi-stage hydraulic cylinder during the well entry process to generate thrust shearing the setting shear pins 209.

[0039] When the upper piston push cylinder 301 moves upward, it pushes the spring seat 212 upward, and the inner spring 210 is squeezed. When the upper end of the spring seat 212 is tightly against the slip seat 208, the annular cavity 214 of the spring seat 212 corresponds to the limiting groove 213, and the outer part of the steel ball 211 can enter the annular cavity 214, and the inner sleeve 207 can move upward. When the spring seat 212 pushes the slip seat 208 upward, the setting shear pin 209 is sheared off. When the spring seat 212 pushes the slip seat 208 and the slip 206 upward, the slip 206 contacts the cone 205. As the spring seat 212 continues to move upward, the inner sleeve 207, the slip seat 208, the slip 206 and the cone 205 move upward synchronously. When the cone 205 moves upward, it drives the lower connecting sleeve 105 upward and squeezes the rubber cylinder 103. At the same time, the slip 206 expands toward the inner wall of the casing. When the rubber sleeve 103 expands and contacts the inner wall of the casing, the slips 206 squeeze the inner wall of the casing. At this time, the teeth in the upper end of the cone 205 bite the locking ring 202, and the packer is set.

[0040] When unsealing, the continuous tubing string is lifted, and the upper unsealing shear nail 8 between the upper joint 6 and the upper connecting sleeve 102 is cut off. Then the upper joint 6 drives the inner center pipe 9, the lower joint 5 and the hydraulic outer cylinder 303 to move upward. When the lower joint 5 contacts the lower end of the lower piston inner cylinder 307, the lower piston inner cylinder 307, the middle piston inner cylinder 305, the upper piston inner cylinder 302, the lower center pipe 201 and the outer center pipe 101 move upward. Since the rubber cylinder 103 is tightly against the casing, the cone 205 cannot move upward, and the lower unsealing shear nail 204 is cut off.

[0041] After the lower unsealing shear pin 204 is cut off, the flange 3 on the inner center tube 9 is misaligned with the sealing ring 4. At this time, the well fluid in the casing can enter between the upper end of the upper piston inner tube 302 and the middle piston push tube 304 through the gap between the inner center tube 9 and the outer center tube 101, the gap between the lower center tube 201 and the inner center tube 9, the gap between the upper piston inner tube 302 and the inner center tube 9, and the first balanced pressure hole 3021. The well fluid in the casing can enter between the upper end of the middle piston inner tube 305 and the upper end of the lower piston push tube 306 through the gap between the inner center tube 9 and the middle piston inner tube 305 and the second balanced pressure hole 3051. The well fluid in the casing can also enter between the upper end of the lower piston inner tube 307 and the start piston 308 through the gap between the inner center tube 9 and the lower piston inner tube 307 through the third balanced pressure hole 3071. At this time, the pressure inside the multi-stage hydraulic cylinder is in a balanced state with the pressure inside the casing, and the coiled tubing is continuously lifted, and the slips 206 and the rubber cylinder 103 are restored to their initial states to complete the unsealing.

[0042] Embodiment 2: Based on Embodiment 1, when multiple packers are used in series, the packer used at the top adopts a 90° sawtooth slip 206 with an anti-top function. The packer at the bottom adopts a slip 206 embedded with an alloy column to enhance the downward suspension force of the water injection string. The combination of two different forms of slip 206 structures enhances the reliability of setting and unsealing of the water injection string.

[0043] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A hydraulic self-sealing packer for composite coiled tubing, comprising an upper joint (6), wherein a flow pipe (7) is fixedly and sealedly connected inside the upper joint (6), characterized in that: The lower end of the upper joint (6) is sealedly connected with an upper connecting sleeve (102) and an inner central tube (9); the flow tube (7) is located in the inner central tube (9); the inner central tube (9) is fixedly connected to the upper joint (6); the upper joint (6) is fixedly connected to the upper connecting sleeve (102) via an upper unsealing shear nail (8); the inner thread of the upper connecting sleeve (102) is sealedly connected with an outer central tube (101); a sealing assembly is provided on the outer central tube (101) below the upper connecting sleeve (102); the lower connecting sleeve (105) is sleeved on the outer central tube (101); a locking ring (202) is sleeved in the annular groove of the outer central tube (101); the locking ring The outer central tube (101) below the outer central tube (202) is provided with a limiting sleeve (203), the limiting sleeve (203) is fixed on the outer central tube (101) by a lower unsealing shear nail (204), the limiting sleeve (203) limits the downward movement of the locking ring (202), the lower end of the lower connecting sleeve (105) is threadedly connected with a cone (205), the inner edge of the upper end of the cone (205) is processed with teeth for engaging with the locking ring (202), the lower end of the outer central tube (101) is fixedly sealed and connected with the lower central tube (201), the lower central tube (201) passes through the cone (205), and the outer side of the lower central tube (201) is provided with an inner sleeve (203). 07), the upper end of the inner sleeve (207) is fixedly connected to the lower end of the cone (205), the outer sleeve of the inner sleeve (207) is provided with a slip seat (208), the upper end of the slip seat (208) is evenly connected with a plurality of slips (206) around the circumference, the slips (206) are in contact with the conical surface of the cone (205), the slip seat (208) is fixedly connected to a hydraulic outer cylinder (303) through a sealing shear pin (209), a spring seat (212) is slidably connected between the hydraulic outer cylinder (303) and the inner sleeve (207), the spring seat (212) and the slip seat (208) are connected through an inner spring (210), the hydraulic outer cylinder (303) and A multi-stage hydraulic cylinder is arranged between the inner center tubes (9); the fixed part of the multi-stage hydraulic cylinder is fixedly connected to the lower center tube (201); the telescopic end of the multi-stage hydraulic cylinder can push the spring seat (212) upward; the lower end of the hydraulic outer cylinder (303) is fixedly connected to a lower joint (5); the lower end of the inner center tube (9) is fixedly sealed to the lower joint (5); the lower end of the flow tube (7) is fixedly sealed to the lower joint (5); a liquid inlet channel (404) is provided on the lower joint (5); the liquid inlet channel (404) is connected to the lower liquid inlet end of the multi-stage hydraulic cylinder; and the lower end of the liquid inlet channel (404) is sealed to a soluble plug (402) via an internal thread.

2. A hydraulic self-sealing packer for composite coiled tubing according to claim 1, characterized in that: The upper end of the packing assembly is tightly against the lower end of the upper connecting sleeve (102); a step is processed on the outer central tube (101) below the packing assembly; the lower connecting sleeve (105) is seated on the step of the outer central tube (101); and the upper end of the lower connecting sleeve (105) is tightly against the lower end of the packing assembly.

3. A hydraulic self-sealing packer for composite coiled tubing according to claim 2, characterized in that: The sealing assembly comprises a plurality of rubber tubes (103) sleeved on the outside of the outer central tube (101), and a spacer ring (104) is arranged between two adjacent rubber tubes (103).

4. A hydraulic self-sealing packer for composite coiled tubing according to claim 1, characterized in that: The lower end of the slip (206) is installed in a dovetail groove on the slip seat (208).

5. The hydraulic self-sealing packer for composite coiled tubing according to claim 1, characterized in that: The multi-stage hydraulic cylinder comprises an upper piston inner cylinder (302), the upper end of the upper piston inner cylinder (302) is fixedly connected to the lower end of the lower center tube (201), the lower end of the upper piston inner cylinder (302) is fixedly and sealedly connected to the middle piston inner cylinder (305), the lower end of the middle piston inner cylinder (305) is fixedly and sealedly connected to the lower piston inner cylinder (307), the lower end of the lower piston inner cylinder (307) is slidably and sealedly connected to the lower joint (5), an upper piston push cylinder (301) is arranged on the outer side of the upper piston inner cylinder (302), the upper end of the upper piston push cylinder (301) is tightly against the lower end of the spring seat (212), the upper end of the upper piston inner cylinder (302) is slidably and sealedly connected to the inner side of the upper piston push cylinder (301), and the lower end of the upper piston push cylinder (301) is fixedly and sealedly connected to The middle piston push cylinder (304) has an inner side of an upper end thereof and is slidably sealed to the outer side of an upper piston inner cylinder (302); the outer side of an upper end thereof and is slidably sealed to the inner side of the middle piston push cylinder (304); the lower end thereof and is fixedly sealed to a lower piston push cylinder (306); the inner side of an upper end thereof and is slidably sealed to the outer side of the middle piston inner cylinder (305); the outer side of an upper end thereof and is slidably sealed to the inner side of the lower piston push cylinder (306); the lower end thereof and is fixedly sealed to a starting piston (308); the inner side of the starting piston (308) and the outer side of the lower piston inner cylinder (307) are slidably sealed to each other.

6. A hydraulic self-sealing packer for composite coiled tubing according to claim 5, characterized in that: The upper piston inner cylinder (302) is provided with a first balancing pressure hole (3021), which is communicated with the gap between the upper piston inner cylinder (302) and the inner center tube (9); the hydraulic outer cylinder (303) is provided with a first inlet hole (1) corresponding to the middle piston push cylinder (304); the middle piston push cylinder (304) above the first inlet hole (1) is provided with a third inlet hole (3041), the third inlet hole (3041) is sealed by the upper end of the middle piston inner cylinder (305); the middle piston inner cylinder (305) below the third inlet hole (3041) is provided with a second balancing pressure hole (3051), the second balancing pressure hole (3052) is communicated with the gap between the upper piston inner cylinder (302) and the inner center tube (9); The pressure hole (3051) is connected to the gap between the middle piston inner cylinder (305) and the inner center tube (9); a second inlet hole (2) corresponding to the lower piston push cylinder (306) is opened on the hydraulic outer cylinder (303); a fourth inlet hole (3061) is opened on the lower piston push cylinder (306) above the second inlet hole (2); the fourth inlet hole (3061) is sealed by the upper end of the lower piston inner cylinder (307); a third balanced pressure hole (3071) is opened on the lower piston inner cylinder (307) below the fourth inlet hole (3061); the third balanced pressure hole (3071) is connected to the gap between the lower piston inner cylinder (307) and the inner center tube (9).

7. A hydraulic self-sealing packer for composite coiled tubing according to claim 6, characterized in that: An annular flange (3) is machined on the outer edge of the inner center tube (9) on the inner side of the upper end of the upper piston inner tube (302), and the flange (3) is in sealing contact with a sealing ring (4) on the inner side of the upper end of the upper piston inner tube (302).

8. The hydraulic self-sealing packer for composite coiled tubing according to claim 1, characterized in that: A limiting groove (213) is provided on the outer side of the lower center tube (201), a ball groove corresponding to the limiting groove (213) is provided on the inner sleeve (207), a steel ball (211) is installed in the ball groove, the inner side of the steel ball (211) is located in the limiting groove (213), the outer side of the steel ball (211) contacts the inner edge of the upper part of the spring seat (212), an annular cavity (214) is provided in the lower part of the spring seat (212), and the outer side of the steel ball (211) can enter the annular cavity (214) after the elastic seat moves upward and the annular cavity (214) corresponds to the ball groove, and the inner sleeve (207) can move upward relative to the lower center tube (201) after the outer side of the steel ball (211) enters the annular cavity (214).

9. The hydraulic self-sealing packer for composite coiled tubing according to claim 1, characterized in that: The upper end of the soluble plug (402) is sealedly connected to the lower joint (5) via a sealing ring (401), and a slit (403) is processed on the lower joint (5) on one side of the soluble plug (402), so that the well fluid can contact the soluble plug (402) through the slit (403).

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