Hydraulically set cementing drillable packer and operating method

Abstract

This invention relates to a hydraulically set cement-extruding drillable packer and its operating method. The packer includes a tubing string, mandrel, upper connector, upper slips, upper cone, upper back ring, rubber sleeve, lower back ring, lower cone, lower slips, piston mechanism, guide valve body, sealing slide valve, setting ball, and plug. This invention can be connected to tubing, drill pipe, or coiled tubing and can be run into horizontal, highly deviated, or vertical wells. It can transmit torque during running and has strong resistance to obstruction. During running, the slide valve opens, automatically connecting the cementing channels without the need for simultaneous fluid injection. It features a built-in piston mechanism and hydraulic setting, eliminating the need for lifting or rotating the tubing string to set the packer. The packer is bidirectionally anchored and has strong pressure resistance. This invention enables high-volume cementing operations, completing packer setting, release, flushing of the packer cavity, cementing, and closing of the cementing channels in a single drilling run, significantly saving drilling rig time and labor costs.

Description

Technical Field

[0001] This invention relates to a downhole tool for oil development, and more particularly to a hydraulically set cement-squeezing drillable packer and its operating method. Background Technology

[0002] During oilfield development, testing, well completion, and workover processes, it is often necessary to permanently or temporarily seal water-producing and abandoned formations. Currently, the domestic solutions for these operations are:

[0003] 1. Cementing using packers or bare tubing is a simple process, but packers used for cementing have low pressure differential resistance and low reliability. If the packer is pulled out too early after cementing, the cementing effect is poor; if it is pulled out too late, the packer is easily solidified by the cement slurry, which is very risky. Cementing using bare tubing is also difficult to control the timing of pulling out the tubing string. In horizontal wells or highly deviated wells, the cement slurry tends to lie flat on the horizontal half-section of the casing and is not easy to squeeze into the target layer.

[0004] 2. Mechanical setting tools set the cement retainer and squeeze out cement. By lifting, lowering and rotating the tubing or drill pipe in one run, the setting of the cement retainer and the squeezing of cement are completed. This method is convenient and reliable, but it has limitations. In highly deviated and horizontal wells, the friction between the tubing and the inner wall of the casing is too great, making it impossible to effectively transmit torque to the mechanical setting tool thousands of meters below the surface. This makes it impossible to operate the mechanical setting tool. Secondly, the mechanical setting tool must be lifted with a large tonnage to complete the setting of the cement retainer. For deep wells, the tubing itself is very heavy, and the setting force of the cement retainer is also very large, which places high demands on the surface lifting equipment and the tensile load resistance of the tubing itself.

[0005] 3. Conventional hydraulic setting tools for cementing can be used in diameter, deviated, and horizontal wells, and have high reliability. However, they require the drilling tools to be pulled out after the first set of the cement holder is set, and then the second set of sealing tubing is run in for cementing operations. This wastes time, occupies drilling rig hours, and is costly. Moreover, during the process of pulling out the first set of the setting tubing and running the second set of the cementing tubing, mud, sediment, or other debris often settles and blocks the opening and closing cementing sleeve inside the sealing center tube of the already set cement holder. This prevents the second set of sealing tubing from effectively opening and closing the cementing sleeve of the cement holder, thus failing to achieve the phenomenon of cementing the lower part of the cement holder.

[0006] 4. In recent years, a hydraulic cement holder with a single tubing string has emerged. Although the setting and release are completed hydraulically in one tubing string operation, during the cement extrusion process, the sliding sleeve at the tail of the holder closes due to the upward pushing of the tubing and the upward bending and contraction of the oil pipe, thus preventing the cement extrusion operation from being completed. Its sliding valve is not resistant to erosion, causing the sliding valve to fail to close and resulting in cement slurry backflow. It cannot solve the problem of large-volume cement extrusion, or the bottom one-way ball valve is eroded and damaged after large-volume cement extrusion construction, which cannot prevent the phenomenon of bottom cement slurry backflow. Summary of the Invention

[0007] To address the above problems, this invention provides a hydraulically set-sealed, drillable packer for cement extrusion and its operating method, enabling high-volume cement extrusion operations. In one drilling run, the packer can be set, released, its internal cavity flushed, cement extrusion performed, and the cement extrusion channel closed.

[0008] The technical solution adopted in this invention is: a hydraulically set-sealing type cement-extruding drillable packer, characterized in that: it includes a tubing, a mandrel, an upper connector, an upper slip, an upper cone, an upper back ring, a rubber sleeve, a lower back ring, a lower cone, a lower slip, a piston mechanism, a guide valve body, a sealing slide valve, a setting ball, and a plug. The mandrel is sleeved outside the tubing. The upper connector, upper slip, upper cone, upper back ring, rubber sleeve, lower back ring, lower cone, lower slip, piston mechanism, and guide valve body are sequentially sleeved on the mandrel from top to bottom. The upper end of the upper connector is fixedly connected to the tubing. A first shearing pin is provided between the upper connector and the sleeve. The lower end of the upper connector is fixedly connected to the mandrel. The upper cone and lower cone are fixedly connected to the mandrel. The upper back ring is connected to the mandrel through a first rolled pin, and the lower back ring is connected to the mandrel through a second rolled pin.

[0009] The piston mechanism includes a thrust piston and a piston cylinder liner. One end of the thrust piston is disposed in the piston cylinder liner cavity, and the other end abuts against the lower slip. A second shear pin is provided between the thrust piston and the piston cylinder liner. A locking ring is provided between the thrust piston and the mandrel. The piston cylinder liner cavity passes through the mandrel and the tube and communicates with the central hole of the tube. The piston cylinder liner is fixedly connected to the mandrel.

[0010] The upper end of the guide valve body is fixedly connected to the spindle, and a plug is provided in the shaft hole at the lower end; the sealing slide valve is sleeved in the guide valve body, and the sealing slide valve is provided with a sealing slide valve through hole. The guide valve body is provided with a guide valve body through hole that cooperates with the sealing slide valve through hole. The internal channel of the guide valve body passes through the sealing slide valve through hole and the guide valve body through hole and communicates with the outside; the end of the elastic claw of the sealing slide valve is locked in the groove at the lower end of the tube column, and a gap is provided between the tube column and the guide valve body for the elastic claw to be released; a ball seat is provided at the lower end of the central hole of the tube column, and a third shearing pin is provided between the ball seat and the tube column. The setting ball is set in the ball seat.

[0011] Preferably, the tubing string includes, from top to bottom, a wellhead connector, a sealing connecting rod, and a switch connector. The wellhead connector is fixedly connected to the upper connector, with a first shear pin between them. The upper end of the sealing connecting rod is fixedly connected to the wellhead connector, and the lower end is fixedly connected to the switch connector. The switch connector has a switch connector through hole, and the mandrel has a mandrel through hole that corresponds to the switch connector through hole. The piston cylinder liner cavity communicates with the central hole of the tubing string through the mandrel through hole and the switch connector through hole. The ball seat is located at the lower end of the central hole of the switch connector.

[0012] Preferably, the connection between the wellhead connector and the sealing connecting rod is provided with a vulcanized sealing ring and a third sealing ring, the switch connector and the mandrel are provided with a seventh sealing ring and a ninth sealing ring, and the switch connector and the ball seat are provided with an eleventh sealing ring.

[0013] Preferably, the upper end of the inner hole of the wellhead connector is provided with a connecting thread, and the outer surface is evenly distributed with bottom milling grooves along the axial direction. The bottom milling grooves cooperate with the protruding ribs in the inner hole of the upper connector.

[0014] Preferably, the outer circular surfaces of both the upper and lower jaws are provided with willow-shaped serrations at a 30° angle to the horizontal direction.

[0015] Preferably, a fourth sealing ring and a fifth sealing ring are provided between the thrust piston and the piston cylinder liner, and a sixth sealing ring is provided between the piston cylinder liner and the spindle.

[0016] Preferably, a first sealing ring is provided between the upper connector and the mandrel.

[0017] Preferably, a retaining ring and a second sealing ring are provided between the rubber sleeve and the mandrel.

[0018] Preferably, an eighth sealing ring is provided between the guide valve body and the spindle, a twelfth sealing ring is provided between the guide valve body and the sealing slide valve, and a thirteenth sealing ring is provided between the guide valve body and the plug.

[0019] A method for using a hydraulically set-sealing type cement-drillable packer, characterized by the following steps:

[0020] Setting process: After the packer is lowered to the designated position, a ball is thrown to pressurize it. The liquid flows into the piston cylinder cavity after passing through the switch connector through hole and the mandrel through hole. The liquid pushes the thrust piston, causing it to move upwards and shear the second shear pin. The thrust piston, along with the locking ring, presses upwards. When the thrust reaches the radial shear limit strength of the first and second coiled leather pins, they break. The movement continues until the upper slip breaks and anchors to the inner wall of the sleeve when the breaking limit force of the upper slip is reached. At the same time, the upper and lower back rings are subjected to the oblique force of the upper cone, lower cone, and rubber sleeve end face. The radial force at the slope causes radial contraction and expansion, while the rubber sleeve is subjected to axial compression, resulting in radial deformation. It adheres tightly to the inner wall of the sleeve, achieving a seal and blocking the flow of fluids above and below. The lower slip opens and anchors simultaneously, preventing the rubber sleeve from retracting. The locking ring slides upwards towards the mandrel and engages with the serrated thread on the outer surface of the mandrel, further locking the setting load. The hydraulic pressure continues to increase until the ball seat experiences a downward shear force sufficient to shear the third shear pin. At this point, the ball seat is knocked down, and the setting ball and ball seat descend to contact the upper end face of the plug. The entire setting process is then complete.

[0021] Release process: When the tubing string is lifted, the upper slip breaks and anchors to the casing. The wellhead connector and the upper connector undergo axial shearing action, cutting off the first shearing pin. The entire tubing string is separated from the packer. At this time, the elastic claw of the sealing slide valve moves upward after being lifted by the groove on the lower side of the switch connector, closing the liquid outlet channel on the side of the guide valve body.

[0022] The process of re-insertion and cement extrusion: The tubing is re-inserted into the inner cavity of the mandrel. The outer vulcanized rubber of the vulcanized sealing ring and the inner surface of the mandrel achieve an interference squeeze seal to prevent the lower fluid from leaking to the upper outer side of the tubing. At the same time, the outer circular surface of the squeezed and deformed rubber tube generates compressive stress with the inner wall of the sleeve, achieving liquid isolation between the upper and lower sides of the rubber tube. The retaining ring and the second sealing ring play a filling role in the middle inner hole space of the squeezed and deformed rubber tube.

[0023] If the sealing slide valve cannot be opened normally during the cement extrusion process and there is a high pressure on the ground, it is determined that debris has filled the space where the sealing slide valve moves downward. At this time, the pipe column needs to be lifted out of the top of the packer to a certain height, and the debris or mud at the bottom of the packer needs to be flushed. Then the pipe column can be inserted again to open the sealing slide valve smoothly, connect the cement extrusion channel between the sealing slide valve and the guide valve body, and carry out the cement extrusion operation again.

[0024] Removing the tubing string: After the cement is squeezed out, simply lift the tubing string to separate it from the packer. At the same time, close the tail sealing valve to ensure that the uncured cement slurry is isolated from the liquid at the tail of the packer.

[0025] This invention can be connected to any type of tubing, drill pipe, or coiled tubing string for use in horizontal, highly deviated, or vertical wells, without restrictions on well conditions or running methods. It can transmit torque during running, exhibits strong resistance to obstruction, and automatically connects the cementing channel upon running, eliminating the need for simultaneous running and injection. It features a built-in piston mechanism and hydraulic setting, eliminating the need for lifting or rotating the tubing string to set the packer. The packer is bidirectionally anchored with strong pressure resistance. The elastic claws on the sealing valve and the cementing channel are relatively independent, preventing cement slurry from flowing through the sides of the elastic claws and eliminating the risk of backflow caused by liquid breaking the claws. This meets the requirements of high-volume cementing processes. During cementing, it avoids tubing shrinkage caused by pump pressure, which could close the valve and prevent continued high-pressure cementing operations. The components are made of easily drillable materials, and the tail section features an anti-drilling structure, eliminating freewheeling during drilling. This invention enables large-volume cement squeezing operations, completing the packer setting, release, packer cavity flushing, cement squeezing, and cement squeezing channel closure in a single drilling run, resulting in significant savings in drilling rig time and labor costs. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the hydraulically seated cement-extruding drillable packer of the present invention.

[0027] Figure 2 This is a schematic diagram showing the well entry status;

[0028] Figure 3 A diagram illustrating the pitching, blocking, and seated blocking positions;

[0029] Figure 4 This is a diagram illustrating the state of the ball being knocked down.

[0030] Figure 5 A schematic diagram showing the state of the tubing string disengaged from the packer as the tubing string is lifted.

[0031] Figure 6 A schematic diagram showing the cement squeezing operation during the re-insertion of the tubing;

[0032] Figure 7 This is a schematic diagram showing the completed cement extrusion operation after the pipe column is lifted.

[0033] Figure 8 A schematic diagram of the structure of the wellhead connector;

[0034] Figure 9 This is a schematic diagram of the upper connector structure;

[0035] Figure 10 This is a schematic diagram of the structure of a sealing slide valve;

[0036] Figure 11 This is a schematic diagram of the guide valve body.

[0037] Figure 12 This is a schematic diagram of the plug structure;

[0038] Figure 13 This is a schematic diagram of the switch connector structure;

[0039] In the diagram: 1. Wellhead connector; 11. Bottom milling groove; 2. Upper connector; 21. Rib; 3. First shear pin; 4. First sealing ring; 5. First set screw; 6. Upper slip; 7. Mandrel; 71. Mandrel through hole; 8. Upper cone; 9. First coiled pin; 10. Upper outer back ring; 11. Upper inner back ring; 12. Rubber sleeve; 13. Retaining ring; 14. Second sealing ring; 15. Lower inner back ring; 16. Lower outer back ring; 17. Second coiled pin; 18. Lower cone; 19. Vulcanized sealing ring; 20. Third sealing ring; 21. Lower slip; 22. Sealing connecting rod; 23. Locking ring; 24. Second shear pin; 25. Thrust piston; 26. Piston cylinder liner; 27. Fourth sealing ring ; 28. Fifth sealing ring; 29. ​​Sixth sealing ring; 30. Switch connector; 301. Switch connector through hole; 302. Groove; 31. Second set screw; 32. Seventh sealing ring; 33. Eighth sealing ring; 34. Ninth sealing ring; 35. Guide valve body; 351. Guide valve body through hole; 352. Positioning hole; 36. Positioning pin; 37. Tenth sealing ring; 38. Setting ball; 39. Eleventh sealing ring; 40. Third shear pin; 41. Ball seat; 42. Twelfth sealing ring; 43. Sealing slide valve; 431. Sealing slide valve through hole; 432. Elastic claw; 44. Thirteenth sealing ring; 45. Third set screw; 46. Plug; 00. Sleeve; 47. Clearance. Detailed Implementation

[0040] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0041] like Figure 1-13As shown, the present invention discloses a hydraulically set-sealing type cement-drillable packer, characterized in that it comprises a tubing, a mandrel 7, an upper connector 2, an upper slip 6, an upper cone 8, an upper back ring (composed of an upper outer back ring 10 and an upper inner back ring 11), a rubber sleeve 12, a lower back ring (composed of a lower inner back ring 15 and a lower outer back ring 16), a lower cone 18, a lower slip 21, a piston mechanism, a guide valve body 35, a sealing slide valve 43, a setting ball 38, and a plug 46. The mandrel 7 is sleeved outside the tubing, and the upper connector 2, upper slip 6, upper cone 8, upper back ring 10, upper inner back ring 11, upper inner back ring 12, upper outer back ring 13, upper inner back ring 14, upper outer back ring 15, lower outer back ring 16, lower cone 18, lower slip 21, a piston mechanism, a guide valve body 35, a sealing slide valve 43, a setting ball 38, and a plug 46. The mandrel 7 is sleeved outside the tubing, and the upper connector 2, upper slip 6, upper inner back ring 10, upper outer back ring 11, upper outer back ring 12, upper outer back ring 13, upper outer back ring 14, upper outer back ring 15, upper outer back ring 16, upper outer back ring 16, upper outer back ring 17, upper outer back ring 18, upper outer back ring 19, upper outer back ring 10, upper outer back ring 1 ... The upper cone 8, upper back ring, rubber sleeve 12, lower back ring, lower cone 18, lower slip 21, piston mechanism and guide valve body 35 are sequentially sleeved on the mandrel 7 from top to bottom; the upper end of the upper connector 2 is fixedly connected to the tube column, and a first shearing pin 3 is provided between the upper connector 2 and the sleeve, and the lower end of the upper connector 2 is fixedly connected to the mandrel 7; the upper cone 8 and the lower cone 18 are fixedly connected to the mandrel 7; the upper back ring is connected to the mandrel 7 through the first rolled leather pin 9, and the lower back ring is connected to the mandrel 7 through the second rolled leather pin 17.

[0042] The piston mechanism includes a thrust piston 25 and a piston cylinder liner 26. One end of the thrust piston 25 is disposed in the cavity of the piston cylinder liner 26, and the other end abuts against the lower slip 21. A second shear pin 24 is provided between the thrust piston 25 and the piston cylinder liner 26. A locking ring 23 is provided between the thrust piston 25 and the spindle 7. The cavity of the piston cylinder liner 26 passes through the spindle 7 and the tube column and communicates with the center hole of the tube column. The piston cylinder liner 26 is fixedly connected to the spindle 7.

[0043] The upper end of the guide valve body 35 is fixedly connected to the spindle 7, and a plug 46 is provided in the shaft hole at the lower end; the sealing slide valve sleeve 43 is provided in the guide valve body 35, the sealing slide valve 43 is provided with a sealing slide valve through hole 431, the guide valve body 35 is provided with a guide valve body through hole 351 that cooperates with the sealing slide valve through hole 431, and the internal channel of the guide valve body 35 passes through the sealing slide valve through hole 431 and the guide valve body through hole 351 to communicate with the outside; the end of the elastic claw 432 of the sealing slide valve 43 is locked in the groove 302 at the lower end of the tube column, and a gap 47 is provided between the tube column and the guide valve body 35 for the elastic claw 432 to be released; a ball seat 41 is provided at the lower end of the center hole of the tube column, and a third shear pin 40 is provided between the ball seat 41 and the tube column, and a setting ball 38 is provided in the ball seat 41.

[0044] In this embodiment, the tubing string includes, from top to bottom, a wellhead connector 1, a sealing connecting rod 22, and a switch connector 30. The wellhead connector 1 is fixedly connected to the upper connector 2, with a first shear pin 3 between them. The upper end of the sealing connecting rod 22 is fixedly connected to the wellhead connector 1, and the lower end is fixedly connected to the switch connector 30. The switch connector 30 is provided with a switch connector through hole 301, and the mandrel 7 is provided with a mandrel through hole 71 that corresponds to and cooperates with the switch connector through hole 301. The piston cylinder liner 26 cavity communicates with the central hole of the tubing string through the mandrel through hole 71 and the switch connector through hole 301. The ball seat 41 is located at the lower end of the central hole of the switch connector 30, with a third shear pin 40 between them.

[0045] In this embodiment, the upper side of the threaded connection at the tail of the sealing connecting rod 22 is provided with a vulcanized sealing ring 19 and a third sealing ring 20. The tail is threadedly connected to a switch connector 30. The tail of the switch connector 30 is connected to an eleventh sealing ring 39 and a ball seat 41 via a third shear pin 40. The inner hole on the upper side of the ball seat 41 is provided with a setting ball 38. The setting ball 38 and the ball seat 41 form a seal under hydraulic pressure, temporarily blocking the lower liquid flow channel, allowing liquid to enter the piston mechanism, thereby achieving the anchoring and sealing of the packer.

[0046] In this embodiment, the outer circular surfaces of the upper slip 6 and the lower slip 21 are provided with willow-shaped serrations at 30° to the horizontal direction. Their surfaces are subjected to a high-frequency quenching process, resulting in high hardness, which is beneficial for forming a strong anchoring force against the inner wall of the sleeve after being subjected to force. The upper slip 6 and the lower slip 21 respectively bear the upward and downward anchoring thrust.

[0047] In this embodiment, the rubber sleeve 12 is compressed and deformed radially. The rubber on the deformed outer circle forms compressive stress with the inner wall of the sleeve 00, thereby sealing the oil sleeve annulus. At the same time, the inner and outer back rings deform radially and stick tightly to the inner wall of the sleeve, preventing the pressure from damaging the rubber on the upper and lower outer sides of the deformed rubber sleeve 12.

[0048] In this embodiment, a second shear pin 24 is provided between the thrust piston 25 and the piston cylinder liner 26. A fourth sealing ring 27 and a fifth sealing ring 28 are respectively installed on the inner and outer sides of the lower tail of the thrust piston 25. The lower inner wall of the piston cylinder liner 26 has threads that are connected to the external threads at the tail of the spindle 7. A sixth sealing ring 29 is installed in the lower inner circular sealing groove of the piston cylinder liner 26.

[0049] Combination Figure 11As shown, in this embodiment, the guide valve body 35 is connected to the lower tail of the spindle 7 by an external thread. The second set screw 31 is fixed on the upper thread of the guide valve body 35. The middle part is provided with a positioning hole 352 and a tenth sealing ring 37. The positioning hole 352 is provided with a positioning pin 36 for installation positioning between the guide valve body 35 and the sealing slide valve 43. The guide valve body 35 is equipped with a twelfth sealing ring 42. There are four evenly distributed ribs and a guide valve body through hole 351 on the lower outer circle. The tail is connected to the internal thread and the external thread of the plug (46). The end of the thread is provided with a thirteenth sealing ring 44 and a third set screw 45.

[0050] In this embodiment, the inner hole on the upper side of the wellhead connector 1 has a conventional tubing female thread, such as... Figure 8 As shown, there are six evenly distributed recessed grooves 11 on the outer circular surface. The recessed grooves 11 are similar to those shown in the figure. Figure 2 The upper part of the upper connector 2 is matched with the inclined surface protrusion 21 with a 30° chamfer in the horizontal direction. It can transmit torque during the insertion of the tubing string into the well, making it easier for the tubing string to move forward in highly deviated or horizontal wells. There are six evenly distributed bottom holes in the middle for installing the shear head part of the first shear pin 3. This is used to overcome the tubing string contraction force generated during the hydraulic setting of the packer, and at the same time provides a temporary connection between the inserted tubing string and the packer and a disengagement function after setting.

[0051] In this embodiment, the rubber sleeve 12 is pressed into an elliptical shape by the opposing forces along the mandrel 7 by the upper cone 8 and the lower cone 18, forming contact compressive stress with the inner wall of the sleeve 00, thereby achieving the sealing of the oil sleeve annulus. The upper back ring and the lower back ring slide and relax radial deformation on the 45° inclined surface compressive force of the sides of the upper cone 8 and the lower cone 18, respectively, and stick to the inner wall of the sleeve, thereby protecting the outer shoulders of the upper and lower sides of the pressurized rubber sleeve 12 and preventing the rubber from being crushed and damaged, thereby achieving high pressure differential sealing.

[0052] Combination Figure 13 As shown, in this embodiment, the switch connector 30 has two evenly distributed waist-shaped through-hole milled grooves (i.e., switch connector through-hole 301) in the middle. The switch connector through-hole 301 and the circular liquid inlet hole at the lower tail of the mandrel 7 (i.e., mandrel through-hole 71) form the liquid inlet channel when the packer is set. The upper end of the thrust piston 25 has a sawtooth thread, which meshes with the locking ring 23. When the pressure enters the inner cavity of the piston cylinder liner 26, the thrust piston 25 moves upward, driving the locking ring 23 to slide upward together, and gradually meshes with the sawtooth thread on the outer circular surface of the mandrel 7 to achieve the locking and anti-retraction function, which can achieve better sealing and anchoring. At the same time, the second shear pin 24 temporarily fixes the thrust piston 25 and the piston cylinder liner 26 within a certain shear force range to prevent the pressure difference caused by the pressure excitement during the insertion of the tubing from causing the piston mechanism to start prematurely and causing the packer to set prematurely.

[0053] In this embodiment, a seal is formed by a tenth sealing ring 37 and a positioning pin 36 on the outer circumference of the guide valve body 35. The protruding part of the tail of the positioning pin 36 is aligned with three milled grooves evenly distributed on the upper outer circumference of the sealing slide valve 43, so that the liquid outlet channel (i.e., the sealing slide valve through hole 431) on the outer circumference of the sealing slide valve 43 is aligned with the liquid outlet channel (i.e., the guide valve body through hole 351) on the lower side of the guide valve body 35, which maximizes the smooth flow of liquid during cement extrusion. Moreover, the liquid outlet channel is relatively independent from the elastic claw 432 on the upper side of the sealing slide valve 43, so the fluid will not pass through the elastic claw 432 of the sealing slide valve 43, and the elastic claw 432 will not be flushed by the fluid, thus preventing damage to the elastic claw 432. This will prevent the sealing valve body from being unable to be pulled out by the feed tube after cement extrusion and thus prevent the backflow of cement slurry caused by the sealing slide valve 43 failing to close effectively after cement extrusion.

[0054] The assembly sequence of the drillable packer of the present invention is as follows: connect the lower thread of the upper connector 2 to the upper thread of the mandrel 7, and install the first sealing ring 4, and tighten the first set screw 5; install the upper collet 6 from the lower side, install the upper cone 8, drill a certain depth on the mandrel 7 through the rolled pin hole of the upper cone 8, and hammer in the first rolled pin 9; install the first outer back ring 10 and the first inner back ring 11; use a rubber hammer to install the retaining ring 13 and the second sealing ring 14 in the rubber sleeve 12, and then install the whole into the middle of the mandrel 7, fitting snugly with the inner and outer back rings; then install the second inner back ring 15 and the second outer back ring 16, and install the lower cone 18 in the same way, and connect the mandrel 7 and the lower cone 18. Drill a hole in the coiled pin, hammer in the second coiled pin 17, install the lower slip 21, screw the locking ring 23 into the sawtooth thread in the upper inner hole of the thrust piston 25, install the fourth sealing ring 27 and the fifth sealing ring 28 into the sealing ring grooves on the inner and outer circular surfaces of the lower end of the thrust piston 25 respectively, and then put them onto the mandrel 7. Hammer the sixth sealing ring 29 into the mandrel 7 from the bottom and connect the internal thread; install the twelfth sealing ring 42 into the upper sealing groove of the sealing slide valve 43, install the tenth sealing ring 37 on the positioning pin 36, and screw it into the positioning hole 352 of the guide valve body 35. Hammer the sealing valve body 43 into the guide valve body 35 from the top until its elastic claw 35 2. The lower step contacts the inner hole step of the guide valve body 35. Note that the milling groove opening phase of the sealing slide valve (43) is aligned with the sinking tail end of the plug (36) so that the sealing slide valve through hole 431 is aligned with the guide valve body through hole 351. Install the eighth sealing ring 33 into the upper inner hole sealing ring groove of the guide valve body 35, connect the tail thread of the mandrel 7, and tighten the second set screw 31. Install the thirteenth sealing ring 44 into the upper sealing ring groove of the plug 46, connect it to the lower tail inner hole thread of the guide valve body 35, and tighten the third set screw 45. At this point, the installation of the drillable packer assembly is completed. Then connect the lower external thread of the wellhead connector 1 to the sealing ring. The internal thread on the upper side of the connecting rod 22 is used to install the vulcanized sealing ring 19 and the third sealing ring 20 on the smooth outer circular surface of the lower side of the sealing connecting rod 22, and connects with the internal thread at the upper end of the connecting switch connector 30. The eleventh sealing ring 39 is installed into the inner hole on the lower side of the switch connector 30. The third shearing pin 40 is installed, and the setting ball 38 is found for later use. At this point, the tool assembly (i.e., the tubing string) is connected. Finally, the insertion tubing string is inserted into the inner hole of the mandrel 7, and the phase is aligned so that the inclined milling groove 11 of the wellhead connector 1 fits with the rib 21 of the upper inner hole of the upper connector 2. Finally, the first shearing pin 3 is installed. At this point, the entire tool string is installed and is ready to be inserted into the well.

[0055] The working principle of this solution is as follows:

[0056] Setting process: After the packer is lowered to the designated position, a ball is thrown from the ground to pressurize it. The liquid flows into the chamber of the piston cylinder liner 26 after passing through the switch connector through hole 301 and the mandrel through hole 71. The thrust piston 25 tends to move upward, shearing the second shear pin 24 and pressing it upward with the locking ring 23. When the thrust reaches the radial shear limit strength of the first coiled leather pin 9 and the second coiled leather pin 17, they break. Then it continues to move. When the rupture limit force value of the upper slip 6 is reached, the upper slip 6 breaks and anchors on the inner wall of the sleeve. At the same time, the upper back ring and the lower back ring are radially contracted and expanded when subjected to the radial component forces of the upper cone 8, the lower cone 18, and the 45° slope at the end face of the rubber sleeve 12, respectively, protecting the axially compressed... The shoulder of the rubber sleeve 12 is not squeezed over, thus better bearing the pressure; at the same time, the rubber sleeve 12 is subjected to axial compression and undergoes radial deformation, with the outer circular surface becoming elliptical and tightly adhering to the inner wall of the sleeve 00 to achieve a seal and block the flow of fluids above and below; the lower slip 21 opens and anchors simultaneously, preventing the rebound force of the rubber sleeve 12 from retracting, and the locking ring 23 slides towards the upper part of the mandrel 7 and engages with the sawtooth thread on the outer surface of the mandrel 7, further locking the setting load; the hydraulic pressure continues to increase until the ball seat 41 is subjected to a downward shear force sufficient to shear the third shear pin 40, at which point the ball seat 41 is knocked down, and the setting ball 38 and the ball seat 41 descend to contact the upper end face of the plug 40, at which point the entire setting process is completed.

[0057] Release process: When the tubing string is lifted, the upper slip 6 is anchored on the casing 00 after cracking, restricting upward axial movement. At this time, the wellhead connector 1 and the upper connector 2 undergo axial shearing action, cutting off the first shearing pin 3, and the entire tubing string is separated from the packer. At this time, the elastic claw 432 of the sealing slide valve 43 moves upward after being lifted at the concave surface 302 on the lower side of the switch connector 30, closing the liquid outlet channel on the side of the guide valve body 35.

[0058] The process of re-insertion and cement extrusion: The tubing is re-inserted into the inner cavity of the mandrel 7. The outer vulcanized rubber of the vulcanized sealing ring 19 and the inner surface of the mandrel achieve an interference squeeze seal, preventing the lower fluid from leaking to the upper outer side of the feeding tool. At the same time, the outer circular surface of the squeezed and deformed rubber sleeve 12 generates a large contact squeeze stress with the inner wall of the sleeve, achieving liquid isolation between the upper and lower sides of the rubber sleeve 12. Furthermore, the retaining ring 13 and the second sealing ring 14 play a filling role in the middle inner hole space of the squeezed and deformed rubber sleeve 12, making the seal more reliable and the pressure resistance higher.

[0059] If the sealing slide valve 43 cannot be opened normally during the re-insertion process and there is a high pressure phenomenon on the ground, it is determined that the space for the sealing slide valve 43 to move downward is filled by debris. At this time, the pipe string needs to be pulled up about 1 meter above the top of the drillable packer, and a large-volume flushing should be started to flush away the debris or mud at the bottom of the packer. After the debris is flushed away, it can be reinserted to open the sealing slide valve 43 smoothly, connecting it with the cement squeezing channel of the guide valve body 35, and the cement squeezing operation can be carried out again.

[0060] During the cement extrusion process, the cement slurry will only pass through the 45° inclined channel of the sealing slide valve 43, and will not flow through the upper elastic claw 432 to mill the gap, thus preventing damage to the three elastic claws 432 of the sealing slide valve 43. This ensures that when the tubing is lifted, the locking joint 30 can smoothly move the sealing slide valve 43 upward, close the cement extrusion channel, and trap the unsolidified cement slurry on the lower side of the packer, achieving the convenience of safely lifting the tubing.

[0061] Meanwhile, during the cement squeezing process, the fluid will only flow into the cement squeezing channel of the bottom guide valve body 35 and the chamber of the piston cylinder liner 26. The thrust generated by the thrust piston 25 will only compress the packer's slip anchoring system and sealing squeezing system more tightly and anchor them more firmly, instead of pushing the pipe column upward like other single-pass cement retainers, causing the pipe column to move upward and thus closing the tail sealing slide valve 43 and the cement squeezing channel of the guide valve body 35.

[0062] Removing the tubing string: After the cement is squeezed out, the tubing string is lifted directly to separate it from the packer. At the same time, the tail sealing valve 43 is closed to ensure the liquid isolation of the cement slurry that has not yet solidified at the tail of the packer.

[0063] It should be noted that the above description of the technical solutions is exemplary, and this specification may be embodied in different forms and should not be construed as limiting it to the technical solutions set forth herein. Rather, providing these descriptions will ensure that the disclosure of this invention is thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art. Furthermore, the technical solutions of this invention are defined only by the scope of the claims.

[0064] Finally, it should be noted that the above embodiments are merely representative examples of the present invention. Obviously, the present invention is not limited to the above embodiments and many variations are possible. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention should be considered within the protection scope of the present invention.

Claims

1. A hydraulically set-sealing type cement-extruding drillable packer, characterized in that: The assembly includes a tubing, a mandrel, an upper connector, an upper slip, an upper cone, an upper back ring, a rubber sleeve, a lower back ring, a lower cone, a lower slip, a piston mechanism, a guide valve body, a sealing slide valve, a setting ball, and a plug. The mandrel is sleeved outside the tubing. The upper connector, upper slip, upper cone, upper back ring, rubber sleeve, lower back ring, lower cone, lower slip, piston mechanism, and guide valve body are sequentially sleeved on the mandrel from top to bottom. The upper end of the upper connector is fixedly connected to the tubing, and a first shear pin is provided between the upper connector and the sleeve. The lower end of the upper connector is fixedly connected to the mandrel. The upper and lower cones are fixedly connected to the mandrel. The upper back ring is connected to the mandrel via a first rolled pin, and the lower back ring is connected to the mandrel via a second rolled pin. The piston mechanism includes a thrust piston and a piston cylinder liner. One end of the thrust piston is disposed in the piston cylinder liner cavity, and the other end abuts against the lower slip. A second shear pin is provided between the thrust piston and the piston cylinder liner. A locking ring is provided between the thrust piston and the mandrel. The piston cylinder liner cavity passes through the mandrel and the tube and communicates with the central hole of the tube. The piston cylinder liner is fixedly connected to the mandrel. The upper end of the guide valve body is fixedly connected to the spindle, and a plug is provided in the shaft hole at the lower end; the sealing slide valve is sleeved in the guide valve body, and the sealing slide valve is provided with a sealing slide valve through hole. The guide valve body is provided with a guide valve body through hole that cooperates with the sealing slide valve through hole. The internal channel of the guide valve body passes through the sealing slide valve through hole and the guide valve body through hole and communicates with the outside; the end of the elastic claw of the sealing slide valve is locked in the groove at the lower end of the tube column, and a gap is provided between the tube column and the guide valve body for the elastic claw to be released; a ball seat is provided at the lower end of the central hole of the tube column, and a third shear pin is provided between the ball seat and the tube column. The setting ball is set in the ball seat; The tubing string includes, from top to bottom, a wellhead connector, a sealing connecting rod, and a switch connector. The wellhead connector is fixedly connected to the upper connector, with a first shear pin between them. The upper end of the sealing connecting rod is fixedly connected to the wellhead connector, and the lower end is fixedly connected to the switch connector. The switch connector has a switch connector through hole, and the mandrel has a mandrel through hole that corresponds to the switch connector through hole. The piston cylinder cavity communicates with the central hole of the tubing string through the mandrel through hole and the switch connector through hole. The ball seat is located at the lower end of the central hole of the switch connector. A first sealing ring is provided between the upper connector and the mandrel.

2. The hydraulically set-sealed cement-extruding drillable packer according to claim 1, characterized in that: The connection between the wellhead connector and the sealing connecting rod is provided with a vulcanized sealing ring and a third sealing ring. The switch connector and the mandrel are provided with a seventh sealing ring and a ninth sealing ring. The switch connector and the ball seat are provided with an eleventh sealing ring.

3. The hydraulically set-sealing type cement-extruding drillable packer according to claim 1, characterized in that: The upper end of the inner hole of the well-feeding connector is provided with a connecting thread, and the outer surface is evenly distributed with bottom milling grooves along the axial direction. The bottom milling grooves cooperate with the protruding ribs in the inner hole of the upper connector.

4. The hydraulically set-sealed cement-extruding drillable packer according to claim 1, characterized in that: Both the upper and lower jaws have willow-shaped serrations on their outer circular surfaces at a 30° angle to the horizontal.

5. The hydraulically set-sealed cement-extruding drillable packer according to claim 1, characterized in that: A fourth sealing ring and a fifth sealing ring are provided between the thrust piston and the piston cylinder liner, and a sixth sealing ring is provided between the piston cylinder liner and the mandrel.

6. The hydraulically set-sealed cement-extruding drillable packer according to claim 1, characterized in that: A retaining ring and a second sealing ring are provided between the rubber sleeve and the mandrel.

7. The hydraulically set-sealed cement-extruding drillable packer according to claim 1, characterized in that: An eighth sealing ring is provided between the guide valve body and the spindle, a twelfth sealing ring is provided between the guide valve body and the sealing slide valve, and a thirteenth sealing ring is provided between the guide valve body and the plug.

8. A method for operating a hydraulically set-sealed cement-drillable packer as described in any one of claims 1 to 7, characterized in that: Includes the following steps: Setting process: After the packer is lowered to the designated position, a ball is thrown to pressurize it. The liquid flows into the piston cylinder cavity after passing through the switch connector through hole and the mandrel through hole. The liquid pushes the thrust piston, causing it to move upwards and shear the second shear pin. The thrust piston, along with the locking ring, presses upwards. When the thrust reaches the radial shear limit strength of the first and second coiled leather pins, they break. The movement continues until the upper slip breaks and anchors to the inner wall of the sleeve when the breaking limit force of the upper slip is reached. At the same time, the upper and lower back rings are subjected to the oblique force of the upper cone, lower cone, and rubber sleeve end face. The radial force at the slope causes radial contraction and expansion, while the rubber sleeve is subjected to axial compression, resulting in radial deformation. It adheres tightly to the inner wall of the sleeve, achieving a seal and blocking the flow of fluids above and below. The lower slip opens and anchors simultaneously, preventing the rubber sleeve from retracting. The locking ring slides upwards towards the mandrel and engages with the serrated thread on the outer surface of the mandrel, further locking the setting load. The hydraulic pressure continues to increase until the ball seat experiences a downward shear force sufficient to shear the third shear pin. At this point, the ball seat is knocked down, and the setting ball and ball seat descend to contact the upper end face of the plug. The entire setting process is then complete. Release process: When the tubing string is lifted, the upper slip breaks and anchors to the casing. The wellhead connector and the upper connector undergo axial shearing action, cutting off the first shearing pin. The entire tubing string is separated from the packer. At this time, the elastic claw of the sealing slide valve moves upward after being lifted by the groove on the lower side of the switch connector, closing the liquid outlet channel on the side of the guide valve body. The process of re-insertion and cement extrusion: The tubing is re-inserted into the inner cavity of the mandrel. The outer vulcanized rubber of the vulcanized sealing ring and the inner surface of the mandrel achieve an interference squeeze seal to prevent the lower fluid from leaking to the upper outer side of the tubing. At the same time, the outer circular surface of the squeezed and deformed rubber tube generates compressive stress with the inner wall of the sleeve, achieving liquid isolation between the upper and lower sides of the rubber tube. The retaining ring and the second sealing ring play a filling role in the middle inner hole space of the squeezed and deformed rubber tube. If the sealing slide valve cannot be opened normally during the cement extrusion process and there is a high pressure on the ground, it is determined that debris has filled the space where the sealing slide valve moves downward. At this time, the pipe column needs to be lifted out of the top of the packer to a certain height, and the debris or mud at the bottom of the packer needs to be flushed. Then the pipe column can be inserted again to open the sealing slide valve smoothly, connect the cement extrusion channel between the sealing slide valve and the guide valve body, and carry out the cement extrusion operation again. Removing the tubing string: After the cement is squeezed out, simply lift the tubing string to separate it from the packer. At the same time, close the tail sealing valve to ensure that the uncured cement slurry is isolated from the liquid at the tail of the packer.

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