CN115539005A

CN115539005A - Dragging fracturing packer for coiled tubing

Info

Publication number: CN115539005A
Application number: CN202211382333.6A
Authority: CN
Inventors: 闫家; 张恒春; 王稳石; 曹龙龙; 施山山; 蒋焕; 王文
Original assignee: Institute of Exploration Technology Chinese Academy of Geological Sciences
Current assignee: Institute of Exploration Technology Chinese Academy of Geological Sciences
Priority date: 2022-11-07
Filing date: 2022-11-07
Publication date: 2022-12-30

Abstract

The invention discloses a dragging fracturing packer for a coiled tubing, which relates to the technical field of packers, and improves the sealing property and the service life of a balance valve core by arranging a composite sealing structure; the reverse circulation is established by utilizing a one-way valve structure consisting of steel balls in the upper joint centralizer, settled sand is discharged by utilizing a runner in the continuous oil pipe, and the runner is additionally arranged on the balance valve core and the upper joint centralizer, so that the reverse circulation flushing effect is enhanced, and the problem of settled sand is solved. The positions below the sealing rubber cylinders are provided with the waist-shaped hole sand discharge grooves which are connected with the central hole of the central rod, so that sand can be discharged in time when settled sand appears in the J-shaped grooves.

Description

Dragging fracturing packer for coiled tubing

Technical Field

The invention relates to the technical field of packers, in particular to a dragging fracturing packer for a coiled tubing.

Background

With the continuous development of various complex track wells such as horizontal wells, side drilling wells and cluster wells in oil fields, a new subject is provided for the fracturing technology. In the existing coiled tubing dragging fracturing packer of an oil field, a lifting type mechanical packer is mainly adopted. The coiled tubing fracturing technology has incomparable advantages compared with the conventional technology that the number of modified layers is not limited, the operation can be dragged under pressure, and a large drift diameter of a fractured shaft is kept.

The main structure of the existing dragging fracturing packer for the coiled tubing is as follows: the device comprises a centralizer, a one-way valve, a switch valve, a sealing rubber cylinder, a slip, a J-shaped sliding rail and a coupling positioner.

The switching valve adopts V type sealing washer or Y type sealing washer sealed, and seal structure is simple, is very easily lost efficacy in the sand inclusion environment, hardly satisfies the demand that one time tubular column drags multistage fracturing in succession, leads to a lot of tripping operation, and operating efficiency and economic nature reduce. Meanwhile, the annular cavity between the upper joint centralizer and the upper joint outer barrel is easy to feed sand and accumulate, once too much sand is accumulated, the opening stroke of the balance valve core is limited and the balance valve core cannot be opened, the upper and lower pressure difference of the packer is large, and the packer cannot be unsealed, so that a drilling accident is caused. The cavity between the friction block and the friction device body cannot be discharged after sand accumulation, so that the friction block cannot be normally contracted in the radial direction after being opened, and the fracture string stuck accident can be caused. Well core rod J type slide rail lacks row's sand structure, and the inside easy long-pending sand of instrument is light then can pile up because of J type slide rail sand grain and lead to the unable design position that moves of guide pin, influences the switching of packer action and function, and heavy then can lead to the cover to locate the outside moving part card of well core rod and die and unable normal action, causes the unable deblocking of packer to arouse the sticking accident.

The conventional dragging fracturing packer for the coiled tubing is usually used for independently matching a casing collar locator for depth correction of the coiled tubing, so that the length of a fracturing tool string is increased, the height of an operation wellhead is increased, and the labor intensity and risk of high-altitude hoisting and installation are increased.

Disclosure of Invention

In order to solve the technical problems, the invention provides a dragging fracturing packer for a continuous oil pipe, which aims to solve the problems of sand blocking and sealing failure of the fracturing packer of a dragging type mechanical packer.

In order to achieve the purpose, the invention provides the following scheme:

the invention provides a dragging fracturing packer for a continuous oil pipe, which comprises an upper joint centralizer, a ball cage, a steel ball, a joint pressing cap, an upper joint outer cylinder, a balance valve core, a sealing sleeve, a sealing rubber cylinder, a rubber cylinder retainer ring, a taper sleeve, a slip retainer ring, a supporting spring, a slip seat, a slip sliding block, a sliding ring, a guide pin and a central rod, wherein the upper joint centralizer is connected with the upper joint centralizer;

the inner axial through hole of the upper joint centralizer is a stepped through hole, a transition surface with gradually reduced diameter is arranged on the stepped through hole, a plurality of through first flow channel grooves are arranged on the side wall of the lower part of the upper joint centralizer, and the first flow channel grooves are communicated with the stepped through hole; the ball cage is arranged in the upper joint centralizer, the steel ball is arranged in the upper joint centralizer and is positioned below the ball cage, and a one-way sealing structure is formed between the steel ball and the transition surface;

a central hole is axially formed in the balance valve core, a second flow channel groove is radially formed in the bottom end of the central hole, and the upper end of the central hole is connected with the bottom end of the upper joint centralizer; a sealing surface is arranged on the outer wall of the balance valve core and above the second flow channel groove;

the upper joint outer cylinder is of a bottomless and cover-free cylindrical structure, a conical surface is arranged at the inner middle upper part of the upper joint outer cylinder, and the conical surface and the sealing surface of the balance valve core form hard sealing; the joint pressing cap is connected with the upper end of the upper joint outer barrel, a movable cavity is formed between the joint pressing cap and the upper joint outer barrel, and the movable cavity is used for controlling the axial stroke of the balance valve core; the middle lower part of the upper joint outer cylinder is provided with the sealing sleeve, and the center of the sealing sleeve is provided with a sealing channel along the axis;

a sealing assembly is arranged on the outer wall of the lower end of the balance valve core; the seal assembly and the seal cartridge form a soft seal;

the upper end of the central rod is connected with the lower part of the upper joint outer barrel, and the upper end of the central rod is used for limiting the axis of the sealing sleeve;

a limiting convex ring is arranged on the outer wall of the middle upper part of the central rod, the rubber cylinder retaining ring and the taper sleeve are sleeved on the central rod, a cavity is formed inside the rubber cylinder retaining ring and the taper sleeve, and the cavity and the limiting convex ring are matched for limiting the axial positions of the rubber cylinder retaining ring and the taper sleeve on the central rod;

the sealing rubber cylinder is sleeved on the central rod and is positioned between the upper joint outer cylinder and the rubber cylinder check ring;

the outer wall of the lower end of the central rod is provided with a J-shaped groove, the J-shaped groove comprises a long groove arranged along an axis and a short groove arranged along the axis, the long groove is connected with the lower end of the short groove through a connecting inclined plane, a guide inclined plane is arranged below the middle part of the connecting inclined plane in the direction opposite to the inclination direction of the connecting inclined plane, and the middle part of the guide inclined plane is positioned right below the long groove and the short groove;

the slip seat, the slip sliding block and the friction device are sequentially arranged on the central rod below the taper sleeve; a plurality of slips are circumferentially arranged on the slip seat, slip retainer rings are arranged in the middles of the slips, and a supporting spring is arranged between the inner wall of one end of each slip, which is far away from the taper sleeve, and the slip seat; the inner wall of the friction device is provided with the sliding ring, the guide pin penetrates through the side wall of the sliding ring and then extends into the J-shaped groove, and the guide pin can slide in the J-shaped groove.

Optionally, the sealing assembly comprises a combined sealing ring, a sealing press ring and a sealing press cap; the combined sealing ring is sleeved on the outer wall of the balance valve core, and the sealing pressing ring and the sealing pressing cap are both in threaded connection with the balance valve core.

Optionally, the friction device comprises an upper fixing ring, a friction device body, a friction block, a casing collar positioning slide block, a spring plate and a lower fixing ring; the upper end of the friction device body is connected with the slip sliding block, and the sliding ring is positioned on the inner wall of the friction device body; a plurality of mounting grooves are formed in the outer wall of the middle of the friction device body along the circumferential direction, and the friction block and the casing collar positioning sliding block are mounted on the mounting grooves; the spring plate is arranged in the mounting groove and used for providing elastic force for the friction block and the casing collar positioning sliding block; go up solid fixed ring set up in the mounting groove upper end is used for fixing the clutch blocks with the upper end of sleeve pipe coupling location slider, gu fixed ring set up down in the mounting groove lower extreme is used for fixing the clutch blocks with the lower extreme of sleeve pipe coupling location slider.

Optionally, the outer wall of the casing collar positioning sliding block is of a tower-shaped stepped structure, the stepped structure is connected through a conical chamfer, the lower cone chamfer of the conical chamfer is small, and the upper cone chamfer of the conical chamfer is large; the sleeve collar positioning slide blocks and the friction blocks are arranged in a staggered mode in the circumferential direction of the friction device body.

Optionally, the outer wall of the friction block is a circular arc surface.

Optionally, the outer wall of the casing collar positioning sliding block is a one-way step surface.

Optionally, a guide shoe is arranged at the lower end of the friction device body; a third flow channel groove is formed in the outer wall of the guide shoe; the guide shoe is matched with the upper joint centralizer and used for centralizing the dragging fracturing packer for the coiled tubing.

Optionally, a pressing cap is arranged in the frictionizer body, the bottom end of the central rod extends into the pressing cap, and the pressing cap is used for centering the central rod and limiting the sliding ring.

Compared with the prior art, the invention achieves the following technical effects:

the balance valve core adopts a composite structure, so that the sealing performance is not influenced while the strength is improved; the switch valve adopts a double-sealing structure, and simultaneously adopts a soft sealing structure and a hard sealing structure so as to improve the reliability and prolong the service life.

And a sand discharge groove is adopted, fluid is used for carrying sand, and sand discharge and washing are carried out on the tool.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without creative efforts.

FIG. 1 is a schematic diagram of the configuration of a drag fracturing packer in a well for a coiled tubing string according to the present invention;

FIG. 2 is a schematic structural view of the upper half section of the coiled tubing in a downhole state by dragging a fracturing packer in accordance with the present invention;

FIG. 3 is a schematic structural diagram of the lower half section of the drag fracturing packer for a coiled tubing string in a downhole state according to the present invention;

FIG. 4 is a schematic structural diagram of a dragging fracturing packer in a lifting state for a coiled tubing according to the present invention;

FIG. 5 is a schematic structural diagram of the upper half section of the dragging fracturing packer in a lifting state for the coiled tubing of the present invention;

FIG. 6 is a schematic structural diagram of the lower half section of the coiled tubing in a pulling state of a dragging fracturing packer;

FIG. 7 is a schematic structural view of the setting state of a frac packer for coiled tubing according to the present invention;

FIG. 8 is a schematic structural view of the upper section of the coiled tubing used in the setting state of the frac tractor packer of the present invention;

FIG. 9 is a schematic structural diagram of the lower half section of the coiled tubing set with a frac tractor packer in a set state;

FIG. 10 is a schematic diagram of the configuration of an upper joint centralizer in a drag frac packer of the present invention for a coiled tubing string;

FIG. 11 is a schematic structural diagram of a balance valve core in a drag fracturing packer for a coiled tubing string according to the present invention;

FIG. 12 is a schematic diagram of the configuration of a center rod in a drag frac packer for a coiled tubing string according to the present invention;

FIG. 13 is a schematic structural diagram of a friction device body in a dragging fracturing packer for a coiled tubing according to the present invention.

Description of reference numerals: 1. an upper joint centralizer; 2. a ball cage; 3. pressing a cap on the joint; 4. an upper joint outer cylinder; 5. a balanced valve core; 6. sealing sleeves; 7. sealing the pressure ring; 8. sealing the pressing cap; 9. a rubber cylinder check ring; 10. a taper sleeve; 11. slips; 12. a slip retainer ring; 13. a support spring; 14. a slip seat; 15. a slip slider; 16. a slip ring; 17. a guide pin; 18. a center pole; 19. a friction body; 20. an upper fixing ring; 21. a friction block; 22. a casing collar positioning slide block; 23. a spring plate; 24. a lower fixing ring; 25. pressing the cap; 26. guiding a shoe;

b1, steel balls; b2, combining a sealing ring; and B3, sealing the rubber cylinder.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

As shown in fig. 1 to 13, the present embodiment provides a dragging fracture packer for a coiled tubing to solve the problems of sand jam and sealing failure of the fracture packer.

The ball cage 2 is arranged on the upper joint centralizer 1 and used for fixing the steel ball B1 to form a one-way valve, so that liquid can only reversely circulate and cannot normally circulate, namely, the liquid can only flow into the coiled tubing from the oil casing annulus and cannot flow into the oil casing annulus from the coiled tubing.

The upper joint centralizer 1, the balance valve core 5, the sealing press ring 7, the sealing press cap 8 and the combined sealing ring B2 form a whole, and the balance valve core 5 is opened and closed.

The joint pressing cap 3 is arranged on the upper joint outer cylinder 4, a movable cavity is provided for the movement of the upper joint centralizer 1 and the valve core, and the movement stroke of the valve core is ensured to just meet the opening and closing requirements.

Sealing clamping ring 7 and sealed pressure cap 8 are installed and are compressed tightly combination seal circle B2 on balanced case 5, and sealing clamping ring 7 and sealed pressure cap 8 can guarantee that combination seal circle B2 is in best operating condition through adjusting axial position control combination seal circle B2 pretightning force simultaneously, and sealing clamping ring 7 and sealed pressure cap 8 can lock each other simultaneously, and is effective locking. A plurality of circulating flow channel grooves are designed on the balance valve core 5, the circulating flow channel grooves and the circulating flow channel grooves on the upper joint centralizer 1 form a complete circulating system, and when sand settling occurs at the upper end of the balance valve core 5, the sand settling can be discharged from the continuous oil pipe through the circulating flow channel grooves through reverse circulation.

The sealing sleeve 6 is arranged in the upper joint outer cylinder 4, is axially compressed and fixed by the central rod 18 and is sealed by an O-shaped ring. The sealing sleeve 6 can form soft sealing with the combined sealing ring B2 to realize the sealing of the balance valve core 5.

Meanwhile, when the balance valve core 5 moves downwards in the upper joint outer cylinder 4, the balance valve core and a matching conical surface in the upper joint outer cylinder 4 can form a hard seal. The axial sealing thrust is provided by the coiled tubing, thereby constituting a dual seal structure. The hard seal is not influenced by gravel and the like, the combined seal ring B2 can be prevented from being scratched by the gravel in the sealing process, and the combined seal ring B2 can make up the problem of poor sealing performance of the hard seal. And the best sealing effect is achieved through complementary cooperation.

And the sealing rubber cylinder B3 is arranged on the central rod 18, the upper side is an upper joint outer cylinder 4, and the lower side is a rubber cylinder check ring 9. The rubber cylinder retainer ring 9 is connected with the taper sleeve 10 to form a large gourd-shaped structure with two small sides and a middle part, a cavity of the gourd-shaped structure is sleeved on the protrusion on the central rod 18, and when the sealing rubber cylinder B3 needs to be compressed, the maximum compression stroke of the sealing rubber cylinder B3 can be adjusted through the size of the cavity, so that the rubber cylinder is guaranteed to reach the optimal compression amount.

The teeterboard structure is composed of the slips 11, the slip retainer ring 12 and the supporting spring 13, under the conventional state, the slips 11 is not tilted on one side of the slips 11 teeth under the action of the supporting spring 13, the slips are prevented from being clamped with a well wall in the well entering process, and meanwhile, the slips 11 teeth are protected from being rubbed with the well wall to avoid abrasion. When setting is needed, the slips 11 move upwards to contact with the conical surface of the taper sleeve 10 and tilt, the supporting spring 13 is compressed, and the slips 11 teeth contact with the well wall to start setting.

The guide pins 17 are positioned through radial holes in the slip ring 16 and then inserted into J-slots in the central rod 18. When the guide pin 17 is positioned in the J-shaped groove of the central rod 18 and slides up and down, the wheel flow can be switched between the long groove and the short groove of the J-shaped groove, and the switching is carried out once every time the wheel slides back and forth. That is, each time the coiled tubing is lifted and lowered, the guide pin 17 is positioned in the J-shaped groove of the central rod 18 to perform switching between the long groove and the short groove. Due to the long groove stroke, when the guide pin 17 enters the long groove, the slips 11 obtain enough stroke, and can compress the sealing rubber cylinder B3 and open to seat with the well wall. When the guide pin 17 enters the short groove, the slip 11 does not have enough stroke to contact with the taper sleeve 10, and the side of the slip 11 without the slip 11 teeth at the lower side is tilted under the action of the supporting spring 13, so that the tool is conveniently driven into a well.

The upper fixing ring 20 and the lower fixing ring 24 are sleeved on the friction device body 19, and the friction block 21 and the casing collar positioning slide block 22 are arranged in a groove of the friction device body 19. The friction blocks 21 and the casing collar positioning slide blocks 22 are installed in the same size, except for the outer surface boss which contacts the well wall. The friction block 21 adopts a flat outer surface, and generates friction force with the well wall when the tool is put on or put down so as to push the guide pin 17 to change direction. The outer surface of the casing coupling positioning sliding block 22 is of a one-way step structure, when the tool is lowered, the effect is the same as that of the friction block 21, when the tool is lifted up, the step on the outer surface can be clamped into a coupling gap of the casing, so that the coiled tubing ground equipment tensiometer obtains an extra load to judge the position of the tool and replace a traditional coupling positioner.

The friction device body 19 is provided with six grooves for installing a friction block 21 or a casing collar positioning slide block 22, and a spring plate 23 is arranged below the friction block 21 or the casing collar positioning slide block 22 and used for providing a certain thrust force for the friction block 21 or the casing collar positioning slide block 22 and ensuring that enough radial force is generated between the friction block and the casing to generate friction force and additional load. The specific installation number of the friction blocks 21, the casing collar positioning slide blocks 22 and the spring plates 23 needs to be determined according to well and construction requirements.

The pressing cap 25 is mounted at the tail of the central rod 18 and is used for righting the friction device body 19. And is also a limiting part of the sliding sleeve.

The guide shoe 26 is arranged at the right end of the friction device body 19 and is used as a bottom cone of the whole tool, and simultaneously plays a role in righting corresponding to the upper joint centralizer 1, and the outer surface of the guide shoe is provided with a circulating runner groove.

The position above the sealing rubber cylinder B3, namely the valve core position of the balance valve, the sand setting is that after the tool is seated, gravel generated at the bottom is accumulated at the upper end of the closed valve core due to gravity in the fracturing operation, so that the valve core cannot be normally opened. The invention utilizes the one-way valve structure formed by the steel ball B1 in the upper joint centralizer 1 to establish reverse circulation, utilizes the flow channel in the coiled tubing to discharge settled sand, adds the flow channel on the balance valve core 5 and the upper joint centralizer 1 to strengthen the circulating flushing effect and solve the problem of settled sand.

The position below the sealing rubber cylinder B3, namely the position of the central rod 18J-shaped groove, the sand settling is caused by the fact that the J-shaped groove is complex in structure, meanwhile, a plurality of parts wrap the periphery of the J-shaped groove, gaps are small, and once the sand settling is formed, the sand settling is difficult to discharge. According to the invention, the waist-shaped hole sand discharge groove is added and is connected with the central hole of the central rod 18, so that when sand setting occurs in the J-shaped groove, the sand can be discharged in time.

It will be evident to those skilled in the art that the invention is not limited to the details of the foregoing illustrative embodiments, and that the present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein, and any reference signs in the claims are not intended to be construed as limiting the claim concerned.

The principle and the implementation mode of the present invention are explained by applying specific examples in the present specification, and the above descriptions of the examples are only used to help understanding the method and the core idea of the present invention; meanwhile, for a person skilled in the art, according to the idea of the present invention, the specific embodiments and the application range may be changed. In view of the foregoing, the description is not to be taken in a limiting sense.

Claims

1. A dragging fracturing packer for a continuous oil pipe is characterized by comprising an upper joint centralizer, a ball cage, a steel ball, a joint pressing cap, an upper joint outer cylinder, a balance valve core, a sealing sleeve, a sealing rubber cylinder, a rubber cylinder retainer ring, a taper sleeve, a slip retainer ring, a supporting spring, a slip seat, a slip sliding block, a sliding ring, a guide pin and a central rod;

the upper joint outer cylinder is of a bottomless and cover-free cylindrical structure, a conical surface is arranged at the inner middle upper part of the upper joint outer cylinder, and the conical surface and the sealing surface of the balance valve core form a hard seal; the joint pressing cap is connected with the upper end of the upper joint outer barrel, a movable cavity is formed between the joint pressing cap and the upper joint outer barrel, and the movable cavity is used for controlling the axial stroke of the balance valve core; the middle lower part of the upper joint outer cylinder is provided with the sealing sleeve, and the center of the sealing sleeve is provided with a sealing channel along the axis;

the outer wall of the lower end of the central rod is provided with a J-shaped groove, the J-shaped groove comprises a long groove arranged along the axis and a short groove arranged along the axis, the long groove is connected with the lower end of the short groove through a connecting inclined plane, a guide inclined plane is arranged below the middle part of the connecting inclined plane in a direction opposite to the inclined direction of the connecting inclined plane, and the middle part of the guide inclined plane is positioned right below the long groove and the short groove;

2. The coiled tubing frac tractor packer of claim 1, wherein said seal assembly comprises a combination seal ring, a seal compression ring and a seal compression cap; the combined sealing ring is sleeved on the outer wall of the balance valve core, and the sealing pressing ring and the sealing pressing cap are both in threaded connection with the balance valve core.

3. The coiled tubing frac-drag packer of claim 1, wherein the friction means comprises an upper retaining ring, a friction block, a casing collar locating slide, a spring plate and a lower retaining ring; the upper end of the friction device body is connected with the slip sliding block, and the sliding ring is positioned on the inner wall of the friction device body; a plurality of mounting grooves are formed in the outer wall of the middle of the friction device body along the circumferential direction, and the friction block and the casing collar positioning sliding block are mounted on the mounting grooves; the spring plate is arranged in the mounting groove and used for providing elastic force for the friction block and the casing collar positioning sliding block; go up solid fixed ring set up in the mounting groove upper end is used for fixing the clutch blocks with the upper end of sleeve pipe coupling location slider, gu fixed ring set up down in the mounting groove lower extreme is used for fixing the clutch blocks with the lower extreme of sleeve pipe coupling location slider.

4. The drag fracturing packer for the coiled tubing of claim 3, wherein the outer wall of the casing collar positioning slide block is in a tower-shaped stepped structure, the stepped structure is connected through a conical chamfer, the lower conical chamfer of the conical chamfer is small, and the upper conical chamfer of the conical chamfer is large; the sleeve collar positioning slide blocks and the friction blocks are arranged in a staggered mode in the circumferential direction of the friction device body.

5. The coiled tubing used dragging fracturing packer of claim 3, wherein the outer wall of the friction block is a circular arc surface.

6. The drag fracture packer for coiled tubing of claim 3, wherein the outer wall of the casing collar locating slider is a one-way step surface.

7. The drag fracturing packer for coiled tubing of claim 3, wherein the lower end of the friction body is provided with a guide shoe; a third flow channel groove is formed in the outer wall of the guide shoe; the guide shoe is matched with the upper joint centralizer and used for centralizing the dragging fracturing packer for the coiled tubing.

8. The frac packer of claim 3, wherein the friction body has a pressure cap disposed therein, the bottom end of the center rod extending into the pressure cap, and the pressure cap is configured to centralize the center rod and to restrain the slip ring.