Releasing drillable bottom packer

Abstract

The utility model provides a releasing drillable type bottom packer. The packer is characterized in that an upper joint is in threaded connection with a mandrel sleeved with a connecting sleeve, and a sealing packing is mounted on the mandrel; the connecting cylinder is in reverse threaded connection with the upper rubber cylinder seat, and a torsion shear pin is arranged on the end face; the central pipe is connected with the upper rubber sleeve; the rubber sleeve, the lower rubber sleeve seat, the cone and the slip assembly are sequentially sleeved on an outer cylinder of the central pipe; the upper releasing connector and the lower releasing connector are fixed together through the releasing shear pin and connected with the central pipe and the centralizing block, and a filtering baffle is arranged in an inner cavity of the upper releasing connector. The packer has the beneficial effects that the packer can be released from the releasing mechanism after casing deformation, and all tool pipe columns for construction in a shaft can be pulled out, so that the construction safety is more reliable; the parts of the tool are made of materials easy to drill and grind, residual tools in the shaft can be effectively treated, and the shaft treatment efficiency is improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to the downhole operation technical field in the field of oil and gas development, specifically relates to a drillable bottom packer. BACKGROUND

[0002] In the process of low-yield and low-efficiency horizontal well reconstruction by using double-sealing single-casing old well repeated volume fracturing reconstruction technology, since the area between the two packers is a high-pressure area, the two sides are low-pressure areas, there is external extrusion pressure on the casing, and in severe cases, casing deformation occurs in the two low-pressure areas, causing sticking accidents. If sticking occurs during the adjustment of the drilling tool, unblocking cannot be achieved through positive flushing, reverse washing, and movable drilling tools, and only the oil pipe can be pulled out by hand, and subsequent processing is required, which seriously delays the construction progress. UTILITY MODEL CONTENTS

[0003] The utility model aims to solve at least one of the above-mentioned deficiencies in the prior art. For example, one of the purposes of the utility model is to provide a drillable bottom packer that is easy to operate, has good sealing performance, and has a stable structure.

[0004] To achieve the above-mentioned purpose, the utility model provides a drillable bottom packer.

[0005] The packer can include a mandrel, a connecting sleeve, a central tube, a drillable joint assembly, and a centralizer, which are connected in sequence, and a rubber sleeve assembly, a cone, and a slip assembly, which are sequentially sleeved on the central shaft; wherein a part of the mandrel is located inside the connecting sleeve, and the mandrel can move axially in the connecting sleeve under the action of an external force, and the maximum outer circumference of the mandrel and the left end face of the connecting sleeve form a limit; the rubber sleeve assembly is located at the upper end of the central tube and includes an upper rubber sleeve seat, a rubber sleeve, and a lower rubber sleeve seat; the upper rubber sleeve seat can be threadedly connected with the connecting sleeve.

[0006] Further, a first shear pin can be provided at the connection between the connecting sleeve and the upper rubber sleeve seat.

[0007] Further, a sealing element can be installed on the outer circumference of one end of the connecting sleeve.

[0008] Further, the sealing element can include a sealing packing.

[0009] Further, the drillable joint assembly can include a drillable upper joint and a drillable lower joint, and the drillable upper joint and the drillable lower joint can be connected by a second shear pin.

[0010] Further, the drillable upper joint is threadedly connected with the lower end of the central tube, and the drillable lower joint is threadedly connected with the centralizer.

[0011] Further, a filter mechanism can be installed in the inner cavity of the drillable upper joint.

[0012] Further, the filter mechanism can include a filter baffle fixed by a screw.

[0013] Further, the packer can further include an upper joint threadedly connected with the mandrel.

[0014] Further, the rubber tube can be made of rubber.

[0015] Compared with the prior art, the beneficial effects of the utility model include at least one of the following contents:

[0016] (1) The utility model has simple structure and low preparation cost.

[0017] (2) The utility model discloses a releasing mechanism, which can realize releasing of the packer from the releasing mechanism after casing deformation, can pull out all tool pipe columns used for construction in the wellbore, and is more reliable in construction safety.

[0018] (3) The utility model discloses a tool part made of material easy to drill and grind, which can effectively process residual tools in the wellbore, and improves the processing efficiency of the wellbore. BRIEF DESCRIPTION OF DRAWINGS

[0019] The above features of the utility model will become more apparent through the following description in combination with the drawings, in which:

[0020] Figure 1 Fig. 1 shows a structure schematic diagram of one exemplary embodiment of the releasing drillable bottom packer of the utility model;

[0021] Figure 2 Fig. 2 shows a setting state schematic diagram of the releasing drillable bottom packer of the utility model;

[0022] Figure 3 Fig. 3 shows a casing deformation and releasing state schematic diagram of the releasing drillable bottom packer of the utility model at the centralizer head;

[0023] Figure 4 Fig. 4 shows a casing deformation and releasing state schematic diagram of the releasing drillable bottom packer of the utility model at the slip assembly.

[0024] MAIN REFERENCE NUMERALS EXPLANATION

[0025] 1-upper joint, 2-mandrel, 3-connection sleeve, 4-sealing packing, 5-torsion shear pin, 6-upper rubber seat, 7-central pipe, 8-rubber tube, 9-lower rubber seat, 10-cone, 11-slip assembly, 12-releasing upper joint, 13-filter baffle, 14-releasing lower joint, 15-releasing shear pin, 16-centralizer, 17-slip anchor, 18-rubber tube packer, 19-casing. DETAILED DESCRIPTION

[0026] Hereinafter, an example of the bottom packer will be described in detail in conjunction with the example of the present application.

[0027] Example 1

[0028] The present example provides a bottom packer.

[0029] The packer comprises a mandrel, a connecting sleeve, a central pipe, a rubber sleeve assembly, a cone, a slip assembly, a releasing sub assembly and a centralizer.

[0030] A part of the mandrel is located in the inner cavity of the connecting sleeve, and the mandrel can move axially in the connecting sleeve under the action of an external force, a limiting structure is formed between the mandrel and the connecting sleeve, and the limiting structure is located inside the upper end of the connecting sleeve, specifically, the limiting structure is formed by the maximum outer circumferential surface of the mandrel and the inner left end surface of the connecting sleeve.

[0031] The rubber sleeve assembly is sleeved on the upper end of the central pipe and comprises an upper rubber sleeve seat, a rubber sleeve and a lower rubber sleeve seat; the upper rubber sleeve seat is threadedly connected with the connecting sleeve.

[0032] The cone is sleeved on the central pipe and located below the rubber sleeve assembly.

[0033] The slip assembly is sleeved on the central pipe and located below the cone.

[0034] The releasing sub assembly can connect the lower end of the central pipe with the upper end of the centralizer.

[0035] In the present example, a first shear pin can be arranged at the connection between the connecting sleeve and the upper rubber sleeve seat.

[0036] In the present example, a sealing element can be mounted on the outer circumferential surface of one end of the mandrel.

[0037] In the present example, the sealing element can comprise a sealing packing.

[0038] In the present example, the releasing sub assembly can comprise a releasing upper sub and a releasing lower sub, and the releasing upper sub and the releasing lower sub can be connected by a second shear pin.

[0039] In the present example, the releasing upper sub is threadedly connected with the lower end of the central pipe, and the releasing lower sub is threadedly connected with the centralizer.

[0040] In the present example, a filter mechanism can be arranged in the inner cavity of the releasing upper sub.

[0041] In the present example, the filter mechanism can comprise a filter baffle, and the filter baffle is fixed by a screw.

[0042] In the embodiment, the packer can further include an upper joint, which is threadedly connected with the mandrel.

[0043] In the embodiment, the rubber tube can be made of rubber.

[0044] In order to better understand the above exemplary embodiments, the following further describes the exemplary embodiments in conjunction with specific embodiments.

[0045] Embodiment 1

[0046] Figure 1 A structure schematic diagram of one exemplary embodiment of the releasing drillable bottom packer is shown. Figure 2 A setting state schematic diagram of the releasing drillable bottom packer is shown. Figure 3 A sleeve change meets a releasing state schematic diagram of the releasing drillable bottom packer at the centralizer head is shown, wherein, Figure 3 The upper diagram in the figure is a state before releasing, the two curves represent sleeve change, and the lower diagram is a state after releasing. Figure 4 A sleeve change meets a releasing state schematic diagram of the releasing drillable bottom packer at the slip assembly is shown, Figure 4 The uppermost part represents a releasing starting part, and the two curves in the middle part represent sleeve change.

[0047] The following describes the embodiment in conjunction with Figures 1-4 The following describes the embodiment in conjunction with

[0048] The releasing drillable bottom packer can include:

[0049] The upper joint 1, the mandrel 2, the connecting sleeve 3, the sealing packing 4, the torsion shear pin 5, the upper rubber tube seat 6, the rubber tube 8, the central tube 7, the lower rubber tube seat 9, the cone 10, the slip assembly 11, the releasing upper joint 12, the filter baffle 13, the releasing lower joint 14, the releasing shear pin 15, and the centralizer block 16. The upper rubber tube seat 6, the central tube 7, the lower rubber tube seat 9, the cone 10, the slip assembly 11, and the centralizer block 16 are made of high-strength aluminum, cast iron, composite materials, and the like, which are easy to be processed by drilling and grinding.

[0050] The packer upper joint 1 is threadedly connected with the mandrel 2. The connecting sleeve 3 is externally sleeved on the mandrel 2 and is threadedly connected with the upper rubber tube seat 6 through reverse (left-handed) threads. The thread root of the connecting threads has an inner step surface at the end face of the two parts. The torsion shear pin 5 is arranged on the step surface, constituting a releasing mechanism one, which is used to control the torque generated by the forward rotation (right-handed) pipe column between the connecting sleeve and the upper rubber tube seat, so as to shear the torsion shear pin and realize the releasing of the packer.

[0051] The center tube 7 is connected with the upper rubber sleeve base 6 through threads, the rubber sleeve 8, the lower rubber sleeve base 9, the cone 10 and the slip assembly 11 are sequentially sleeved on the outer cylindrical surface of the center tube. When the packer is in the setting action, the center tube 7 drives the upper rubber sleeve base 6, the rubber sleeve 8, the lower rubber sleeve base 9 and the cone 10 to contact the slip assembly 11, the slip is opened to anchor the casing 19, and the reaction force generated by the continuous downward movement causes the cone 10 to press the lower rubber sleeve base 9 upwards, the lower rubber sleeve base 9 further presses the rubber sleeve 8 to cause the rubber sleeve 8 to expand and set, and the annulus is formed in the set layer.

[0052] The release upper joint 12 and the release lower joint 14 are connected with the lower end of the center tube 7 and the upper end of the centralizing block 16 through threads to form the release mechanism two, and the release mechanism two is connected with the center tube 7 and the centralizing block 16 through threads. The release shear pin 15 can bear the tension generated when the packer is normally pulled up to release, and when the tension cannot be normally pulled up, the shear force can be generated by increasing the pulling tension to forcibly shear the release shear pin 15, and at this time, the packer is released from the centralizing block 16.

[0053] The packer release mechanism is provided with two parts, the release mechanism one is at the connection between the upper rubber sleeve base 6 and the connecting sleeve 3, the two parts are connected through left-handed threads, and a stepped surface of the end face abutting part is provided with a torsional shear pin 5; the release mechanism two is at the intermediate connection between the centralizing block 16 and the center tube 7, the convex surface of the release upper joint 12 can be embedded in the concave surface in the cavity of the release lower joint 14, and the release is fixed through the release shear pin 15, the release upper joint 12 is internally provided with a filter baffle 13 which is fixed through a screw, and mainly plays a role of filtering impurities and throttling in the packer. When the packer needs a certain internal diameter, a tubing tool smaller than the internal diameter of the center tube 7 can be lowered, a certain downward thrust is applied to open the filter baffle 13, and the internal diameter of the packer is kept consistent.

[0054] The packer mandrel 2 is composed of multiple cylindrical steps, and the smallest stepped surface is provided with a sealing packing 4, the mandrel 2 can move up and down in the connecting sleeve 3, and is limited through the largest stepped surface, when moving downward to the limiting position, the packing seal 4 enters the inner cavity of the center tube 7 to realize sealing.

[0055] In order to better understand the above embodiment, the use method of the packer is further described below.

[0056] The use method of the packer comprises:

[0057] (1) The packer is lowered into the well and set

[0058] The downhole state is as follows Figure 1As shown, the packer is conveyed into the well by tubing, and after reaching the operating interval, the tubing string is pulled up beyond the rail switching distance to switch the packer setting rail, and then the tubing string is lowered to make the packer descend and insert into the lumen of the central pipe 7, the inside of the packer is in a sealed state, and at the same time, the central pipe 7 drives the connection sleeve 3, the upper rubber seat 6, the rubber sleeve 8, the lower rubber seat 9, and the cone 10 outside the sleeve to continue to descend and contact the upper slips of the slip assembly 11, and after the slips are anchored to the inner wall of the casing 19, the slips no longer descend, and the reaction force causes the cone to extrude the lower rubber seat 9, and the lower rubber seat 9 further extrudes the rubber sleeve 8 to cause the rubber sleeve 8 to expand and set, forming an upper and lower annulus to seal the formation, and the state of the packer after setting is as shown in Figure 2 .

[0059] (2) Packer unsetting

[0060] When the packer is unset, the mandrel 2 is moved upward to disengage from the lumen of the central pipe 7 by pulling up the tubing string, and the internal seal of the packer is removed, at which time the annulus pressure above the wellbore and the annulus pressure below the wellbore are connected through the internal passage of the packer, and the pressure gradually balances, and the mandrel 2 drives the connection sleeve 3, the central pipe 7, and the upper rubber seat 6 to move upward, the rubber sleeve 8 is reset by its own elastic force, the cone 10 is disengaged from the contact surface of the slip assembly 11, the slips are recovered and returned to the original position through the rail, at which time the packer is completely unset, and returns to the state as shown in Figure 1 .

[0061] (3) Packer stuck and releasing

[0062] Case 1: During the adjustment of the position of the packer after the completion of the operation, the packer can be unset, but it cannot be pulled up normally when it is stuck, which is judged to be caused by the deformation of the casing at the righting block of the packer, and the releasing mechanism two can be used to release the hand.

[0063] As shown in Figure 3 , the releasing upper joint 12 and the releasing lower joint 14 are fixedly connected through the releasing shear pin 15, the releasing shear pin 15 can bear the tension generated by normal pulling, when it cannot be pulled up normally due to resistance, the shear force can be generated by increasing the pulling tension, and the releasing shear pin 15 is forcibly sheared off, at which time the righting block 16 is disengaged from the central pipe of the packer, the packer is released from the stuck part, and the whole tool string can be taken out from the casing deformation position, and the residual righting block 16 remains in the wellbore, which can maintain a large internal diameter and can be used for normal production, and does not affect the subsequent wellbore production.

[0064] Case 2: During the adjustment of the position of the packer after the completion of the operation, the packer cannot be unset, and it cannot be released by positive flushing, reverse washing, and movable drilling tools, which is judged to be caused by the deformation of the casing at the slip assembly of the packer, and the releasing mechanism one can be used to release the hand.

[0065] As shown inFigure 4 As shown, the lost-hand mechanism one torsional shear pin 5 is arranged at the connecting position of the rubber sleeve base 6 and the connecting sleeve 3, the two parts are connected through left-handed thread connection, a stepped surface is arranged at the root of the thread, the torsional shear pin 5 is arranged on the stepped surface, in the normal construction process, the torsional shear pin 5 will not be subjected to force to cause the packer to appear the unexpected lost-hand phenomenon. When the packer encounters resistance and cannot be unblocked, the pipe string is rotated in the forward (right-handed) direction, a large enough torque is generated to shear the torsional shear pin 5, and the rubber sleeve base 6 and the connecting sleeve 3 are disconnected, and the packer is lost-hand from the stuck part.

[0066] In addition to the rubber sleeve, the residual parts after the lost-hand are made of aluminum, cast iron or high-strength composite material with certain strength and easy to drill and grind, and after the tool pipe string is pulled out of the wellbore, the residual parts can be effectively treated through the drilling and grinding mode, if only the internal passage of the wellbore needs to be reserved for production and drainage, a small-diameter oil pipe can be lowered into the wellbore to pass through the center pipe 7 of the packer, and the filter baffle 13 at the lost-hand joint is pushed open, so that the internal passage of the pipe string is ensured.

[0067] Embodiment 2

[0068] On the basis of the packer in Embodiment 1, the packer does not include the lost-hand mechanism two, and only includes the lost-hand mechanism one.

[0069] Embodiment 3

[0070] On the basis of the packer in Embodiment 1, the packer does not include the lost-hand mechanism one, and only includes the lost-hand mechanism two.

[0071] In summary, the advantages of the lost-hand drillable bottom packer of the utility model can include:

[0072] (1) The utility model is simple to operate, and is operated by lifting and lowering the pipe string, which is convenient for the later treatment of the part of the wellbore where the casing is stuck, and avoids causing complex engineering.

[0073] (2) The utility model has good sealing performance, the sealing packing on the mandrel enters the center pipe to form a sealed cavity, so that the annulus is formed above and below the packer, and the risk of casing deformation is reduced.

[0074] (3) The design of the utility model has two lost-hand mechanisms, which is convenient for automatic lost-hand, and the whole tool pipe string in the wellbore is pulled out, so that the structure is more reasonable, and the construction safety is more reliable.

[0075] (4) The utility model is made of materials that are easy to drill and grind, and can effectively treat the residual tools in the wellbore, thereby improving the efficiency of the wellbore treatment.

[0076] Although the utility model has been described above in combination with the example embodiments and the drawings, it should be clear for those skilled in the art that various modifications can be made to the above embodiments without departing from the spirit and scope of the claims.

Claims

1. A drill-out, releaseable bottom packer, comprising: The packer comprises a mandrel, a connecting sleeve, a central pipe, a releasing sub assembly and a centralizer which are connected in sequence, and a rubber sleeve assembly, a cone and a slip assembly which are sequentially sleeved on the central shaft; wherein, A part of the mandrel is located inside the connecting sleeve, and the mandrel can move axially in the connecting sleeve under the action of an external force, and the maximum outer circumferential surface of the mandrel and the left end surface inside the connecting sleeve form a limit; The rubber sleeve assembly is located at the upper end of the central pipe and comprises an upper rubber sleeve seat, a rubber sleeve and a lower rubber sleeve seat; the upper rubber sleeve seat can be threadedly connected with the connecting sleeve.

2. The drillable slip-type bottom packer of claim 1, wherein, A first shear pin is arranged at the connection between the connecting sleeve and the upper rubber sleeve seat.

3. The drillable slip-type bottom packer of claim 1, wherein, A sealing element is installed on the outer circumferential surface of one end of the mandrel.

4. The drillable slip-type bottom packer of claim 3, wherein, The sealing element comprises a sealing packing.

5. The drillable slip-type bottom packer of claim 1, wherein, The releasing sub assembly comprises a releasing upper sub and a releasing lower sub, and the releasing upper sub and the releasing lower sub are connected by a second shear pin.

6. The drillable slip-type bottom packer of claim 5, wherein, The releasing upper sub is threadedly connected with the lower end of the central pipe, and the releasing lower sub is threadedly connected with the centralizer.

7. The drillable slip-type bottom packer of claim 5, wherein, A filtering mechanism is arranged in the inner cavity of the releasing upper sub.

8. The drillable slip-type bottom packer of claim 7, wherein, The filtering mechanism comprises a filtering baffle which is fixed by a screw.

9. The drillable slip-type bottom packer of claim 1, wherein, The packer further comprises an upper sub which is threadedly connected with the mandrel.

10. The drillable slip-type bottom packer of claim 1, wherein, The material of the rubber sleeve is rubber.

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