Coiled tubing bottom packer and coiled tubing dragging fracturing process pipe column with bottom seal

Abstract

The utility model provides a coiled tubing bottom packer and a coiled tubing dragging fracturing process pipe column with a bottom seal, the coiled tubing bottom packer comprises a core shaft, an anti-jacking anchoring mechanism, a rubber sleeve and a seat clamping tile, the left end of the core shaft is connected with an upper joint, and a packing sealing assembly is installed at the right end of the core shaft; the anti-jacking anchor fluke mechanism comprises an anchor fluke base and an anchor fluke, the anchor fluke is installed in the anchor fluke base, an inner hole is formed in the left end of the anchor fluke base in the axial direction, and the packing sealing mechanism can be fixed in the inner hole; the rubber sleeve is installed on the anchor fluke base, the rubber sleeve has a certain elastic deformation performance and can expand and contract, a cone is arranged on the right side of the rubber sleeve, and a seating slip is arranged on the right side of the cone. The coiled tubing dragging fracturing process pipe column with the bottom seal comprises the coiled tubing bottom packer. According to the coiled tubing bottom packer, coiled tubing bottom seal dragging fracturing construction can be continuously carried out under a high pump stopping pressure block.

Description

Technical Field

[0001] The utility model relates to the technical field of staged fracturing transformation of low-permeability oil and gas field reservoirs, and specifically to a coiled tubing bottom packer and a coiled tubing with a bottom packer and a fracturing process column. Background Art

[0002] The coiled tubing drag fracturing process and tools have the characteristics of unlimited-level fine-layered fracturing, full-bore completion, and controllable scale fracturing, and have become the main process technology for staged fracturing transformation of low-permeability oil and gas field reservoirs. The bottom packer used in the currently maturely applied coiled tubing with bottom seal drag fracturing process is mainly the Y211 type packer, which relies on lifting and lowering the pipe string and applying mechanical setting drilling pressure to achieve the packer setting. When the construction of the next layer is completed after the construction of one layer, because the formation has been opened and the operation process is under pressure throughout the whole process, there will be a certain pressure in the wellbore - called the formation stop pump pressure in the industry. During the hydraulic sandblasting perforation operation, the upper annulus sealed by the packer will be opened, and the sand-carrying fluid injected from the tubing will be ejected from the outlet of the hydraulic ejector nozzle to form erosion and perforation on the inner wall of the casing, and return to the surface process along the upper annulus wellbore. During the perforation process, the formation stop pump pressure will have an upward effect on the set packer. When the conventional Y211 packer is used as the bottom seal, after the perforating sand-carrying fluid is returned to the surface process during the perforating process, it needs to pass through the throttling effect of the ground throttling manifold to generate a certain throttling pressure - called back pressure in the industry, and the back pressure is used to balance the upward force of the formation pump stop pressure on the packer. At this time, the back pressure controlled by the ground throttling manifold will cause the oil pressure in the perforating process to increase, increasing the construction risk, and with the current equipment, the Y211 bottom seal can only meet the construction of wells with a pump stop pressure not exceeding 30MPa. However, there are blocks with pump stop pressures far exceeding 30MPa in oil fields in Southwest China, Xinjiang, Changqing, Qinghai, etc., and there is a demand for fine and dense cutting of continuous tubing. Therefore, it is necessary to provide a continuous tubing bottom packer that can adapt to the construction of blocks with high pump stop pressures.

[0003] A Chinese patent with publication number "CN113513287A" and name "A Negative Pressure Sealing Packer" discloses a negative pressure sealing packer. The negative pressure sealing packer includes a sealing mechanism, an anchoring mechanism is arranged at the bottom of the sealing mechanism, and a straightening body mechanism is arranged at the bottom of the anchoring mechanism; the anchoring mechanism includes a slip frame and a plurality of slips, and the slips are installed inside the slip frame through a hoop; an annular ring is arranged on the outer side of the slip frame at the top of the slip, and a pushing device is arranged on the annular ring; the utility model designs the slips to be detachable, the elastic plate is opened, and the top ends of the two opened plates are pushed to separate from each other, and the elastic plate can be hung on the right-angle rod, so that the top ends of the opened plates do not need to be pressed against the inner wall of the casing, thereby reducing the deformation of the casing and the wear of the slips, and the foreign matter at the eversion seat can be cleaned through the cooperation of the pushing device and the limiting device, thereby preventing the friction between the slips and the casing and improving the efficiency of recovery. Different from the application, the utility model provides a bottom packer for continuous tubing that can realize perforation-free back pressure control. The packer is provided with a packing seal assembly at the right end of the core shaft. The packing seal assembly can be fixed in the anchor base to form a sealing layer, and the rubber sleeve expands in the sleeve to form a sealing layer on the other side, thereby forming an upper and lower annular structure. Anchor claws are provided in the anchor claw base, and the anti-uplift anchoring mechanism starts working quickly under the action of the upper and lower annular pressure difference, forming an anchoring effect on the packer, and preventing the upper and lower annular pressure difference from causing the packer itself to slip and fail. In the absence of upper annular back pressure control, the packer can still achieve reliable isolation by relying on its own anchoring, and can realize the bottom seal dragging fracturing construction of continuous tubing without perforation back pressure control. Utility Model Content

[0004] The purpose of the present invention is to solve at least one of the above-mentioned deficiencies in the prior art. For example, one of the purposes of the present invention is to provide a coiled tubing packer with self-anchoring and perforation-free back pressure control to prevent top-up. For another example, another purpose of the present invention is to provide a coiled tubing with bottom seal towing fracturing process string.

[0005] In this exemplary embodiment, the continuous oil tubing bottom packer may include a core shaft, an anti-lifting anchoring mechanism, a rubber cylinder and a sitting cava, wherein the left end of the core shaft is connected to the upper joint, and a packing sealing mechanism is installed on the right end of the core shaft; the anti-lifting anchor claw mechanism includes an anchor claw base and an anchor claw, and an anchor claw hole is opened in the circumferential direction of the anchor claw base body, and the anchor claw is installed in the anchor claw hole. The anchor claw can extend from the anchor claw base in a direction away from the anchor claw hole and retract into the anchor claw hole, and an inner hole is opened in the axial direction of the left end of the anchor claw base, and the packing sealing mechanism can be fixed in the inner hole; the rubber cylinder is installed on the anchor claw base, and the rubber cylinder has a certain elastic deformation performance and can expand and contract. A cone is arranged on the right side of the rubber cylinder, and a sitting cava is arranged on the right side of the cone.

[0006] In this exemplary embodiment, a connecting sleeve may be provided in the coaxial direction between the right end of the core shaft and the left end of the fluke base.

[0007] In this exemplary embodiment, a balancing channel may be opened in the circumferential direction of the connecting sleeve wall.

[0008] In this exemplary embodiment, the packing sealing mechanism may include a packing sealing assembly and a packing pressing cap, the packing pressing cap is fixedly connected to the core shaft, and the packing sealing assembly is arranged at the left end of the packing pressing cap.

[0009] In this exemplary embodiment, a step hole may be provided at the inner left end of the connecting sleeve, the right end of the core shaft may pass through the connecting sleeve port and be fixed at the step hole, and the right end of the core shaft passes through the step hole at the left end of the connecting sleeve and is fixed in the connecting sleeve.

[0010] In this exemplary embodiment, the outer side wall of the fluke may be sleeved with a fluke sealing ring.

[0011] In this exemplary embodiment, a pressure plate may be provided on the fluke base at the opening of the fluke hole.

[0012] In this exemplary embodiment, an elastic mechanism may be provided between the pressure plate and the fluke.

[0013] In this exemplary embodiment, a lower rubber cylinder seat may be provided on the fluke base at the right end of the rubber cylinder, a cone may be connected to the right end of the lower rubber cylinder seat, and the lower rubber cylinder seat can slide left and right on the anchor base.

[0014] On the other hand, the utility model provides a continuous oil tubing with bottom seal dragging fracturing process string, the continuous oil tubing with bottom seal dragging fracturing process string includes a continuous oil tubing connector, a check valve, a safety release, a rigid stabilizer, a hydraulic ejector, a mechanical coupling positioner, a guide stabilizer and a continuous oil tubing bottom seal as described in the above exemplary embodiment.

[0015] Compared with the prior art, the beneficial effects of the present invention include at least one of the following:

[0016] (1) The packer provided by the utility model can be used in the continuous tubing bottom seal dragging fracturing construction process, which can realize the perforating operation process without back pressure control, reduce the oil pressure during the perforating operation, and reduce the construction safety risk.

[0017] (2) The packer provided by the utility model can continue to carry out the coiled tubing bottom seal dragging fracturing construction in the high pump stop pressure block.

[0018] (3) The utility model provides a continuous oil pipe with bottom seal dragging fracturing process with a simple structure and high construction efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The above and other objects and / or features of the present invention will become more apparent through the following description in conjunction with the accompanying drawings, in which:

[0020] Figure 1 A schematic diagram of the unsealing state of the bottom packer of the coiled tubing according to an exemplary embodiment of the utility model is shown;

[0021] Figure 2 Shows Figure 1 Schematic diagram of the local structure of part A;

[0022] Figure 3 A state diagram of the hydraulic sandblasting perforation stage in which the anchor claws are extended after the coiled tubing bottom packer is set according to an exemplary embodiment of the utility model is shown;

[0023] Figure 4 A state diagram of the hydraulic sandblasting perforation stage in which the anchor claws are not extended after the oil extension tubing bottom packer is set according to an exemplary embodiment of the utility model is shown.

[0024] Description of reference numerals:

[0025] 1- casing, 2- upper joint, 3- sealing ring, 4- core shaft, 5- connecting sleeve, 51- balance channel, 6- backwash hole, 71- packing sealing assembly, 72- packing pressure cap, 91- anchor claw base; 92- pressure plate, 93- pressure plate screw, 94- anchor claw, 95- spring, 96- anchor claw sealing ring, 10- rubber cylinder, 11- lower rubber cylinder seat, 12- cone; 13- sitting cava. DETAILED DESCRIPTION

[0026] Hereinafter, the coiled tubing bottom packer and the coiled tubing with bottom packer dragging fracturing process string of the present invention will be described in detail in conjunction with the accompanying drawings and exemplary embodiments.

[0027] It should be noted that "first", "second", etc. are only for the convenience of description and distinction, and should not be understood as indicating or implying relative importance. "upper", "lower", "inner", "outer", etc. are only for the convenience of description and forming a relative orientation or position relationship, and should not indicate or imply that the referred parts must have such a specific orientation or position.

[0028] First Exemplary Embodiment

[0029] The present exemplary embodiment provides a coiled tubing bottom packer.

[0030] Figure 1 A schematic diagram of the unsealing state of the bottom packer of the coiled tubing according to an exemplary embodiment of the utility model is shown; Figure 2 Shows Figure 1The following is a schematic diagram of the local structure of part A. Figures 1-2 The coiled tubing bottom packer of the present exemplary embodiment will be described.

[0031] In this exemplary embodiment, Figure 1 As shown in , the continuous tubing bottom packer mainly includes a core shaft 4, an anti-uplift anchoring mechanism, a rubber cylinder 10 and a seat cava 13. The left end of the core shaft 4 is connected to the upper joint 2, and a sealing ring 3 is sleeved between the connecting ends of the core shaft 4 and the upper joint 2. Here, the sealing ring can be a commonly used sealing original in downhole tools in the oil industry, which can block liquids of different pressure values ​​to ensure that the hydraulic pressure is not connected. A packing sealing mechanism is installed at the right end of the core shaft 4. An anti-uplift anchoring mechanism is arranged at the right end of the packing sealing mechanism. The anti-uplift anchoring mechanism includes an anchor claw base 91 and an anchor claw 94. An inner hole can be opened in the axial direction of the left end of the anchor claw base 91, and a sealing surface is arranged in the inner hole. When the packer is seated, the packing sealing mechanism can be inserted and fixed in the sealing surface of the inner hole to form a layer of sealing. Anchor claw holes may be provided on the body of the anchor claw base 91 in the circumferential direction, and an anchor claw 94 is provided in the anchor claw hole, which can extend from the anchor claw base 91 in the direction away from the anchor claw hole and retract into the anchor claw hole. A rubber cylinder 10 is installed at the right end of the anchor claw base 91. The rubber cylinder 10 has a certain elasticity. When the packer is set, it can expand to be close to the inner wall of the casing 1 to form another layer of seal. At this time, the size of the sealing surface formed by the expanded rubber cylinder and the inner wall of the casing is much larger than the outer diameter size of the packing seal assembly. The two seals form the overall sealing effect after the packer is set, that is, the wellbore isolation is divided into two pressure systems of the upper and lower annuli. Here, the upper annulus can be the casing annulus space at the right end of the rubber cylinder after the rubber cylinder is expanded. The lower annulus can be the casing annulus space at the left end of the packing seal assembly after the packing seal assembly is inserted into the inner hole.

[0032] In this exemplary embodiment, Figure 2 As shown in , a connecting sleeve 5 may be provided between the right end of the mandrel and the left end of the anchor base 91. The right end of the mandrel 4 may be fixed in the connecting sleeve 5 and connected to the connecting sleeve 5 in a limited position. For example, a step hole may be provided inside the left end of the connecting sleeve 5, the right end of the mandrel is inserted into the connecting sleeve 5 and passes through the step hole, and the right end of the mandrel and the step hole are connected to each other to achieve a limited position connection. In addition, the right end of the connecting sleeve 5 may be fixedly connected to the left end of the anchor base 91, for example, by threading. In addition, as Figure 1 , 2 As shown in , 3 or 4, a backwash hole 6 may be further provided in the circumferential direction of the connecting sleeve to ensure that when the drill is stuck due to sand deposition or deposited impurities, the channel can be circulated and flushed through the backwash hole 6 to ensure normal operation of the construction.

[0033] In this exemplary embodiment, Figure 1As shown in FIG. 2 , a balance channel 51 may be provided in the circumferential direction of the connecting sleeve 5. When the packer is unsealed, the balance channel 51 can communicate the pressure in the upper annular pressure system with the pressure in the lower annular pressure system.

[0034] In this exemplary embodiment, Figure 1 As shown in FIG. 4 , a packing pressing cap 72 may be provided at the right end of the core shaft 4 of the packing sealing assembly 71 . The packing pressing cap 72 limits the packing sealing assembly 71 on the core shaft 4 to prevent the packing sealing assembly 71 from falling off the core shaft during construction.

[0035] In the present exemplary embodiment, an anchor seal ring 96 is sleeved on the outer side wall of the anchor 94 to form another sealing layer on the basis of the sealing layer formed by the packing seal assembly, the core shaft and the rubber sleeve.

[0036] In this exemplary embodiment, Figure 1 As shown in FIG. 2 , a pressure plate 92 may be provided at the top of the fluke hole. When the fluke 94 is not extended, it may be restricted in the fluke hole by the pressure plate 92. Further, an elastic mechanism, such as a spring 95, may be provided between the fluke 94 and the pressure plate 92. Under the elastic action of the elastic structure, the fluke 94 may be retracted into the fluke hole. In addition, the pressure plate 92 may be fixed to the fluke base 91 by providing a fixing member, such as a pressure plate screw 93.

[0037] In this exemplary embodiment, Figure 1 As shown in the figure, the lower rubber cylinder seat 11, the cone 12 and the seat clasps 13 can be sequentially arranged on the fluke base 91 at the right end of the rubber cylinder 10. The lower rubber cylinder seat 11 is fixedly connected with the cone 12, for example, by thread connection. It can slide left and right on the fluke base to squeeze the rubber cylinder 10 to expand the rubber cylinder.

[0038] Second Exemplary Embodiment

[0039] This exemplary embodiment provides a coiled tubing with a bottom seal and a dragging fracturing process string.

[0040] In this exemplary embodiment, the continuous tubing with bottom seal dragging fracturing process string mainly includes a continuous tubing connector, a check valve, a safety release, a rigid centralizer, a hydraulic ejector, a mechanical coupling positioner, a guide centralizer and the continuous tubing bottom seal as described in the first exemplary embodiment above.

[0041] In this exemplary embodiment, in order from top to bottom, the tubing string structure may be a coiled tubing connector, a check valve, a safety release, a rigid centralizer, a hydraulic ejector, a coiled tubing bottom packer, a mechanical coupling locator and a guide centralizer.

[0042] In order to better understand the above exemplary embodiments, the above exemplary embodiments are further described and elaborated in combination with Examples 1 and 2 below.

[0043] Example 1

[0044] This example provides a method for setting a coiled tubing bottom packer.

[0045] Figure 3 The diagram shows a hydraulic sandblasting perforation stage state diagram of the coiled tubing bottom packer with the anchor claws extended after the coiled tubing bottom packer is set according to an exemplary embodiment of the present invention.

[0046] In this example, the method for setting the coiled tubing bottom packer includes the following steps:

[0047] During construction, the coiled tubing bottom packer of the utility model is connected to the oil bottom packer drag fracturing construction pipe string to form a tool string, which is driven by the coiled tubing to the bottom of the well and to the position of the layer to be constructed. Figure 3 As shown in , a certain mechanical drilling pressure can be applied through the continuous oil pipe, which causes the cone 12 to contact the sitting cava 13, expand the sitting cava 13 and bite it to the inner wall of the casing 1, forming an upward support for the cone 12. At the same time, the core shaft 4 is inserted downward into the anchor claw base 91, and the packing seal assembly 71 is inserted into the inner hole of the anchor claw base 91. The packing seal assembly 71 forms a sealing isolation between the core shaft 4 and the inner hole of the anchor claw base 91. Continue to increase the drilling pressure, the conical surface on the anchor claw base 91 continues to squeeze the rubber cylinder 10, so that the rubber cylinder 10 expands and fits to the inner wall of the casing 1, forming an isolation for the wellbore. Thus, upper and lower annuli are formed. Here, the pressure of the lower annulus is the formation pump stop pressure after the construction of the previous layer is completed.

[0048] In this example, if Figure 3As shown in , after the packer is sealed, the oil pipe or the upper annulus can be pumped and pressurized to verify the sealing of the upper annulus formed by the rubber tube 10. If the sealing is qualified, the packer is sealed reliably, and the next step of hydraulic sandblasting perforation can be started. During the hydraulic sandblasting perforation operation, the upper annulus formed by the rubber tube 10 can be opened to release pressure. At the same time, the sand-carrying liquid is pumped from the oil pipe, and the sand-carrying liquid flows downward through the oil pipe to the hydraulic ejector, and is ejected at the outlet of the hydraulic ejector nozzle, causing erosion and perforation on the inner wall of the casing 1, forming hydraulic sandblasting perforation. At this time, when the upper annulus pressure relief channel is opened, the upper annulus pressure slowly decreases, forming a certain pressure difference with the lower annulus pressure. When the pressure difference reaches a certain value (theoretically 0.5-0.8MPa), under the action of the pressure difference, the anchor claw 94 will extend outward from the anchor claw base 91 body to bite the inner wall of the casing 1, thus anchoring the anchor claw base 91 and even the entire packer and the pipe string. At the same time, the pressure difference will also generate a piston force on the entirety of the packer isolation, and the piston force will act on the packer as an upward push. When the pressure difference is less than the starting pressure of the anchor claw 94, the value of the upward force is relatively small, and the mechanical drilling pressure applied by the continuous tubing can balance the upward force. At the same time, the seal formed by the mandrel 4 inserted into the anchor claw base 91, the sealing surface as a piston will also be subjected to the upward force of the pressure difference between the lower annulus and the upper annulus, but the outer diameter of the packing seal assembly 71 is much smaller than the sealing surface size formed by the inner wall of the casing 1 after the rubber cylinder 10 expands, and its upward force value is also much smaller (the outer diameter of the packing seal assembly is only 1 / 5 of the inner diameter of the casing, and the upward force value is only 1 / 25), which can be balanced by the mechanical drilling pressure applied by the continuous tubing. Therefore, the packer is always in a stable and reliable setting state. Furthermore, when the pressure difference increases to the point where the anchor claws 94 start to bite into the inner wall of the casing 1, the anchoring force generated by the anchor claws 94 can balance the upward force of the pressure difference on the entire packer. At this time, the packer is always in a stable and reliable sealing state, and the tubing pump water injection sandblasting perforating operation can be smoothly implemented.

[0049] Example 2

[0050] This example provides a method for releasing a bottom packer of a coiled tubing.

[0051] Figure 4 A state diagram of the hydraulic sandblasting perforation stage in which the anchor claws are not extended after the oil extension tubing bottom packer is set according to an exemplary embodiment of the utility model is shown.

[0052] In this example, if Figure 4As shown in , after the packer completes the hydraulic sandblasting perforation operation, the upper annulus drainage channel can be closed, and the tubing pumping displacement can be reduced at the same time, and the upper annulus can be slowly pressurized to perform a formation rupture test. The formation rupture test process may include the following steps: when the upper annulus pressure rises from zero and rises to be equal to the lower annulus pressure, the anchor claw 94 of the anti-uplift anchor claw mechanism retracts into the body of the anchor claw base 91 under the elastic force of the spring 95, and no longer has an anchoring function.

[0053] like Figure 4 As shown, at this time, the anchor claw 94 is retracted into the body of the anchor claw base 91, and the coiled tubing bottom packer still maintains the original sealing state under the mechanical drilling pressure. The upper annular pressure continues to be increased to perform the formation rupture test. During the process of continuing to increase the pressure, the anchor claw 94 is always in a retracted state until the pressure is increased to a certain value to cause the formation to rupture and form a main fracturing crack channel, thereby achieving formation pressure breaking.

[0054] In this example, when the test formation pressure is broken, the tubing pumping and the upper annulus large-volume pumping are started to perform the main fracturing construction on the layer section. During the main fracturing construction process, theoretically, the upper annulus pressure will be higher than the lower annulus pressure, and the anchor claw 94 of the anti-uplift anchor claw mechanism is always in a retracted state, not in contact with the inner wall of the casing 1, and no anchoring effect is produced. After the main fracturing pumping construction procedure is completed, the pumping is stopped, and the upper annulus pressure drops immediately. When the upper annulus pressure drops and tends to stabilize, it is the construction pump-off pressure of the layer. The pump-off pressure after the construction of this layer is theoretically higher than the lower annulus pressure sealed by the packer, that is, the pump-off pressure after the construction of this layer is theoretically higher than the pump-off pressure after the construction of the previous layer. At this time, the anchor claw 94 of the anti-uplift anchor claw mechanism will not start working, that is, it will not form an anchoring effect on the packer. After the construction pump-off pressure of this layer is stable, the packer can be unsealed by lifting the continuous tubing. At this time, the upper joint 2 and the core shaft 4 are lifted upward, and the core shaft 4 is pulled out from the inner hole of the anchor claw base 91. The upper annulus and the lower annulus are connected through the balance channel 51, and the pressure of the upper and lower annuli tends to be balanced. Continue to lift the pipe column, the core shaft 4 drives the connecting sleeve 5 upward, and the connecting sleeve 5 drives the anchor claw base 91 upward. The upward movement of the anchor claw base 91 will release the squeezing and expansion of the rubber cylinder 10, and the rubber cylinder 10 rebounds and shrinks under the action of its own rubber elasticity. Continue to lift, the cone 12 is separated from the sitting cava 13, and the sitting cava 13 is no longer stretched and engaged with the inner wall of the casing 1. Continue to lift, and the packer completely realizes the unsealing action.

[0055] In this example, after the packer is unsealed, it can be lifted up to the next construction layer to continue the same construction operation.

[0056] In summary, the advantages of the present invention may include at least one of the following:

[0057] (1) The packer provided by the utility model can still achieve reliable isolation by its own anchoring even when the upper annulus back pressure control is not performed, and can realize the bottom seal dragging fracturing construction of the coiled tubing without perforation back pressure control.

[0058] (2) The continuous oil tubing with bottom seal dragging fracturing process pipe string provided by the utility model does not need back pressure control to ensure reliable sealing of the packer during hydraulic sandblasting perforation operations, and can be applied to wells in blocks with higher pump-off pressures.

[0059] Although the coiled tubing bottom packer and the coiled tubing with bottom packer dragging fracturing process string of the present invention have been described above in combination with exemplary embodiments, those skilled in the art should be aware that various modifications and changes may be made to the exemplary embodiments of the present invention without departing from the spirit and scope defined by the claims.

Claims

1. A coiled tubing bottom packer, characterized in that: The coiled tubing bottom packer comprises a mandrel, an anti-lift anchoring mechanism, a rubber cylinder and a sitting cava, wherein: The left end of the mandrel is connected to the upper joint, and a packing sealing mechanism is installed on the right end of the mandrel; The anti-lifting anchor claw mechanism comprises an anchor claw base and an anchor claw, wherein the anchor claw base body is provided with an anchor claw hole in the circumferential direction, the anchor claw is installed in the anchor claw hole, the anchor claw can extend from the anchor claw base in a direction away from the anchor claw hole and retract into the anchor claw hole, an inner hole is provided in the axial direction of the left end of the anchor claw base, and the packing sealing mechanism can be fixed in the inner hole; The rubber cylinder is installed on the anchor claw base. The rubber cylinder has a certain elastic deformation performance and can expand and contract. A cone is arranged on the right side of the rubber cylinder, and a seat cava is arranged on the right side of the cone.

2. The coiled tubing bottom packer according to claim 1, characterized in that: A connecting sleeve is arranged coaxially between the right end of the core shaft and the right end of the fluke base.

3. The coiled tubing bottom packer according to claim 2, characterized in that: A balancing channel is provided in the circumferential direction of the connecting sleeve wall.

4. The coiled tubing bottom packer according to claim 1, characterized in that: The packing sealing mechanism comprises a packing sealing assembly and a packing pressing cap. The packing pressing cap is fixedly connected to the core shaft, and the packing sealing assembly is arranged at the left end of the packing pressing cap.

5. The coiled tubing bottom packer according to claim 2, characterized in that: A step hole is arranged at the left end of the inner side of the connecting sleeve, the right end of the core shaft passes through the connecting sleeve port and is fixed at the step hole, and the right end of the core shaft passes through the step hole at the left end of the connecting sleeve and is fixed in the connecting sleeve by limiting position.

6. The coiled tubing bottom packer according to claim 1, characterized in that: The outer side wall of the fluke is sleeved with a fluke sealing ring.

7. The coiled tubing bottom packer according to claim 1, characterized in that: A pressing plate is arranged on the fluke base at the opening of the fluke hole.

8. The coiled tubing bottom packer according to claim 7, characterized in that: An elastic mechanism is arranged between the pressure plate and the fluke.

9. The coiled tubing bottom packer according to claim 1, characterized in that: A lower rubber cylinder seat is arranged at the right end of the rubber cylinder, a cone is connected to the right end of the lower rubber cylinder seat, and the lower rubber cylinder seat can slide left and right on the anchoring base.

10. A coiled tubing with bottom seal dragging fracturing process string, characterized in that: The coiled tubing with bottom seal dragging fracturing process string includes a coiled tubing connector, a check valve, a safety release, a rigid centralizer, a hydraulic ejector, a mechanical coupling positioner, a guide centralizer and a coiled tubing bottom seal as described in any one of claims 1 to 9.

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