A ball-free fracturing packer tool and its fracturing packing method

Abstract

The present invention provides a ball-free fracturing packoff tool, comprising: a mandrel, a lower cone, an upper cone, slips, a sealing unit and a releasing cap; a setting nut is connected to the lower part of the mandrel, and a threaded connection part is arranged at the upper end of the mandrel; the inner side of the lower end of the lower cone is sleeved and matched with the mandrel and the setting nut, and a buttress thread is arranged on the inner side of the upper end of the lower cone; the upper cone is sleeved on the upper part of the mandrel, and elastic claws are arranged at the lower end of the upper cone; the lower part of the slips is in contact with the conical surface of the lower cone, and the upper part is in contact with the conical surface of the upper cone. A plurality of long slotted grooves are staggered on the upper and lower edges of the slips; the sealing unit is located at the upper port of the slips and is sleeved on the outer conical surface of the upper cone; the releasing cap is sleeved on the mandrel, and the lower end of the releasing cap abuts against the upper end of the upper cone; wherein, the above-mentioned components are all made of soluble metal materials. The present invention also provides a ball-free fracturing packoff method, which is implemented by using the above-mentioned ball-free fracturing packoff tool.

Description

Technical Field

[0001] The present invention relates to the technical field of oilfield drilling and production tools, and particularly relates to a ball-free fracturing packer tool and a fracturing packing method thereof. Background Art

[0002] At present, the soluble fracturing tools applied on site mainly include soluble bridge plugs, soluble ball seats, etc. Such tools mostly adopt the traditional process of first setting in the casing, then removing the setting tool, and finally putting in a soluble ball and pumping it to the tool setting position to start normal staged fracturing.

[0003] For example: 1. A low-temperature soluble bridge plug (201820403801.6), including a mandrel, a fracturing ball, an upper packer body, a lower packer body, and a low-temperature soluble gel cartridge; the mandrel is a hollow structure, and the fracturing ball cooperates with the hollow structure of the mandrel to block the hollow structure of the mandrel; the upper packer body, the low-temperature soluble gel cartridge, and the lower packer body are sequentially sleeved outside the mandrel, and the upper packer body and the lower packer body fix the low-temperature soluble gel cartridge on the surface of the mandrel; the low-temperature soluble gel cartridge, the mandrel, the fracturing ball, the upper packer body, and the lower packer body can all dissolve in a low-temperature solution. The low-temperature soluble bridge plug can meet the requirements of wellbore pressure bearing on site. By using the low-temperature soluble gel cartridge, the volume of insoluble materials is minimized, avoiding the blockage of pipelines by insoluble materials. At the same time, the workover cost is saved and the economic benefit is improved. 2. An anchored fully soluble fracturing ball seat (201821570809.8), including a mandrel, an upper cone, a slip, and a lower cone. The upper cone is connected to the upper end of the mandrel through an upper pin, and the lower cone is connected to the lower end of the mandrel through a lower pin. The slip is located in the middle of the mandrel, and the upper and lower ends of the slip are respectively sleeved on the outer walls of the upper cone and the lower cone. The utility model can meet the requirements of full-bore and infinite-stage fracturing transformation; the ball seat can be set at any position, sealing the lower section for fracturing the upper section, and the transformation position and the number of transformation sections are not limited and can be adjusted flexibly; after the ball seat is set, a soluble metal ball is put in for fracturing construction. All ball seats are metal-sealed and are not affected by high downhole temperatures, with high reliability; the ball seat structure is simple, and all components are soluble metal materials with a fast dissolution rate; after the fracturing construction is completed, the soluble ball and the ball seat all dissolve by themselves, and the entire wellbore forms a unified bore, without diameter reduction or enlargement, which is beneficial to subsequent operations.

[0004] However, for horizontal wells, especially long horizontal wells, the process of pumping soluble balls requires consuming at least one well volume of fracturing fluid and also takes extra time. Therefore, it is necessary to innovate in terms of tool design to further improve efficiency, reduce the cost of fracturing construction, and continuously improve the volume fracturing technology level of Changqing Oilfield. Summary of the Invention

[0005] In view of this, the purpose of the present invention is to provide a ball-free fracturing packer tool and a fracturing packing method thereof, which are used to overcome the above problems or at least partially solve or alleviate the above problems.

[0006] The present invention provides a ball-free fracturing packoff tool, comprising:

[0007] A mandrel, a setting nut is connected to the lower part of the mandrel, and a threaded connection part is arranged at the upper end of the mandrel;

[0008] A lower cone, the inner side of the lower end of the lower cone is sleeved and matched with the mandrel and the setting nut, and a buttress thread is arranged on the inner side of the upper end of the lower cone;

[0009] An upper cone, the upper cone is sleeved on the upper part of the mandrel, and an elastic claw is arranged at the lower end of the upper cone;

[0010] A slip, the lower part of the slip is in contact with the conical surface of the lower cone, and the upper part is in contact with the conical surface of the upper cone. A plurality of long slotted holes are alternately arranged at the upper and lower edges of the slip;

[0011] A sealing unit, the sealing unit is located at the upper port of the slip, and the sealing unit is sleeved on the outer conical surface of the upper cone;

[0012] A releasing cap, the releasing cap is sleeved on the mandrel, and the lower end of the releasing cap abuts against the upper end of the upper cone;

[0013] Wherein, the above-mentioned components are all made of soluble metal materials.

[0014] The present invention also has the following optional features.

[0015] Optionally, a breaking groove is arranged on the side wall below the threaded connection part.

[0016] Optionally, a shoulder is further arranged on the side wall of the mandrel, and the upper cone is sleeved on the mandrel below the shoulder.

[0017] Optionally, the releasing cap is sleeved on the outside of the shoulder, and a limiting necking is arranged at the upper end of the releasing cap, and the diameter of the limiting necking is smaller than the outer diameter of the shoulder.

[0018] Optionally, the opening end of the long slotted hole is rectangular and the inner end is circular.

[0019] Optionally, a first embedded groove is arranged on the slip, the first embedded groove is located at the upper edge of the slip, and diamond abrasive teeth are arranged in the first embedded groove.

[0020] Optionally, a second embedded groove is further arranged on the slip, the second embedded groove is located at the lower edge of the slip, and ceramic anchor bolts are arranged in the second embedded groove.

[0021] The present invention also provides a ball-free fracturing packoff method, which is implemented by using the above-mentioned ball-free fracturing packoff tool, and comprises the following steps:

[0022] Step S001: Connect a tubing string and a setting tool to the upper end of the mandrel 1 of the ball-free fracturing packer tool, and lower the ball-free fracturing packer tool to a preset position in the casing.

[0023] Step S002: Push the release cap and the upper cone downward through the setting tool to drive the slips to open until the elastic claws of the upper cone engage and lock with the serrations of the lower cone.

[0024] Step S003: Pull up the mandrel through the setting tool to shear the threaded connection between the lower end of the mandrel and the setting nut, separating the setting nut from the mandrel. The shoulder of the mandrel contacts the upper end of the release cap at the reduced diameter. Continue to pull up the mandrel to break the mandrel from the break-off groove, thus completing the release.

[0025] Step S004: Start pumping on the ground. Under the action of the fluid in the tubing string, the mandrel moves downward until the shoulder contacts the upper cone, and the lower end of the mandrel passes through the lower cone. At this time, the ball-free fracturing packer tool is sealed.

[0026] The ball-free fracturing packer tool and the fracturing packing method of the present invention connect the tubing string and the setting tool through the mandrel. After being lowered to the preset position in the casing, the release cap and the upper cone can be pushed downward through the setting tool to drive the slips to open, and the elastic claws of the upper cone engage and lock with the serrations of the lower cone. When the mandrel is pulled up by the setting tool to shear the threaded connection between the lower end of the mandrel and the setting nut, separating the setting nut from the mandrel, the shoulder of the mandrel contacts the upper end of the release cap at the reduced diameter and breaks the mandrel from the break-off groove to complete the release. After pumping starts on the ground, under the action of the fluid in the tubing string, the mandrel moves downward until the shoulder contacts the upper cone, and the lower end of the mandrel passes through the lower cone, completing the sealing. The position changes among the mandrel, the upper cone, the lower cone, the slips, and the sealing unit form a seal. After the fracturing tool is set, the tool string can be retrieved with a cable without having to drop a ball, and pumping can be directly started for fracturing. Sealing is achieved through the upper cone, the sealing unit, the slips, the lower cone, and the mandrel, eliminating the need to pump soluble balls for plugging. Especially in horizontal wells, fracturing fluid is saved, pumping time is saved, and high-altitude operation of workers is avoided, which is beneficial to protecting the safety of personnel. Moreover, the tool can degrade automatically in the wellbore after fracturing and can automatically restore the wellbore diameter, which is beneficial to subsequent re-entry operations. Description of the Drawings

[0027] Figure 1 is a schematic diagram of the downhole pumping state of the ball-free fracturing packer tool of the present invention;

[0028] Figure 2 is a schematic diagram of the state of the ball-free fracturing packer tool of the present invention after the diameter change is completed;

[0029] Figure 3It is a schematic diagram of the state of the ball-free fracturing and packing tool of the present invention after shearing the sealing nut and releasing it;

[0030] Figure 4 It is a schematic diagram of the sealing state of the ball-free fracturing plugging tool of the present invention.

[0031] In the above figure: 1 core shaft; 101 threaded connection part; 102 break groove; 103 shaft shoulder; 2 sealing nut; 3 lower cone; 301 horse tooth buckle; 4 upper cone; 401 elastic claw; 5 slip; 501 long cutting groove; 502 first embedding groove; 503 second embedding groove; 6 sealing unit; 7 release cap; 701 limit shrinkage.

[0032] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. DETAILED DESCRIPTION

[0033] Example 1

[0034] refer to Figure 1 The embodiment of the present invention provides a ball-free fracturing and sealing tool, comprising: a mandrel 1, a lower cone 3, an upper cone 4, a slip 5, a sealing unit 6 and a release cap 7; the lower part of the mandrel 1 is connected with a sealing nut 2, and the upper end of the mandrel 1 is provided with a threaded connection part 101; the inner side of the lower end of the lower cone 3 is fitted with the mandrel 1 and the sealing nut 2, and the inner side of the upper end of the lower cone 3 is provided with a tooth button 301; the upper cone 4 is fitted on the upper part of the mandrel 1, and the lower end of the upper cone 4 is provided with a An elastic claw 401 is provided; the lower part of the slip 5 contacts the conical surface of the lower cone 3, and the upper part contacts the conical surface of the upper cone 4, and a plurality of long cutting grooves 501 are staggered on the upper and lower edges of the slip 5; the sealing unit 6 is located at the upper end of the slip 5, and the sealing unit 6 is sleeved on the outer conical surface of the upper cone 4; the release cap 7 is sleeved on the core shaft 1, and the lower end of the release cap 7 is pressed against the upper end of the upper cone 4; wherein the above-mentioned components are all made of soluble metal materials.

[0035] When the ball - free fracturing packer tool of the present invention is in use, first connect the upper end of the mandrel 1 to the tubing and the setting tool through the threaded connection part 101, and then lower the ball - free fracturing packer tool to a preset position in the horizontal section of the oil well casing; then push the release cap 7 and the upper cone 4 downward through the setting tool, drive the slips 5 to open, and the sealing unit 6 on the upper cone 4 is also squeezed upward along the conical surface by the slips 5 and opens accordingly until the elastic claws 401 of the upper cone 4 are engaged and locked with the buttress threads 301 of the lower cone 3. At this time, the slips 5 are anchored at the preset position in the horizontal section of the oil well casing, and the sealing unit 6 seals the space between the upper cone 4 and the oil well casing at the same time; then pull the mandrel 1 upward through the setting tool, so that the threaded connection between the lower end of the mandrel 1 and the setting nut 2 is sheared, the setting nut 2 is separated from the mandrel 1 until the mandrel 1 is broken, thus completing the release; finally, start the pump on the ground. Under the action of the fluid in the tubing, the mandrel 1 moves downward until the lower end of the mandrel 1 passes through the lower cone 3 and plugs the inner hole of the lower cone 3. At this time, the ball - free fracturing packer tool is sealed. During the sealing process, there is no need to throw balls, and the pump can be directly started for fracturing, saving fracturing fluid, saving pumping time, and also avoiding high - altitude operation of the operators, which is beneficial to protecting the safety of personnel. Moreover, all the above - mentioned components are made of soluble metal materials. Therefore, after a certain period of time, all the components start to melt, and the wellbore diameter can be automatically restored, which is beneficial to subsequent re - entry well operations.

[0036] Embodiment 2

[0037] Reference Figure 1 , on the basis of Embodiment 1, a pull - off groove 102 is provided on the side wall below the threaded connection part 101.

[0038] A pull - off groove 102 is provided on the side wall below the threaded connection part 101 of the mandrel 1. When the mandrel 1 is released by pulling it upward through the setting tool after setting, the mandrel 1 can break at the pull - off groove 102.

[0039] Embodiment 3

[0040] Reference Figure 1 , on the basis of Embodiment 1, a shoulder 103 is further provided on the side wall of the mandrel 1, and the upper cone 4 is sleeved on the mandrel 1 below the shoulder 103.

[0041] When the setting tool pulls the mandrel 1 upward, the threaded connection between the lower end of the mandrel 1 and the setting nut 2 is sheared. When the nut 2 and the mandrel 1 are just separated, the shoulder 103 can block the upper end of the release cap 7 and prevent the relative movement between the release cap 7 and the mandrel 1.

[0042] Embodiment 4

[0043] Reference Figure 1, on the basis of Embodiment 3, the releasing cap 7 is sleeved on the outside of the shoulder 103, and a limiting necking 701 is provided at the upper end of the releasing cap 7, and the diameter of the limiting necking 701 is smaller than the outer diameter of the shoulder 103.

[0044] The releasing cap 7 is sleeved on the mandrel 1 and the shoulder 103, and the diameter of the limiting necking 701 at the upper port of the releasing cap 7 is smaller than the outer diameter of the shoulder 103, which can be used to form a blocking structure with the shoulder 103 to avoid the relative movement between the releasing cap 7 and the mandrel 1.

[0045] Embodiment 5

[0046] Reference Figure 2 , on the basis of Embodiment 1, the opening end of the long slotted groove 501 is rectangular and the inner end is circular.

[0047] The long slotted grooves 501 at both edges of the slips 5 are distributed alternately. The opening ends are rectangular and the inner ends are circular. When the slips 5 are squeezed by the inclined surfaces of the upper cone 4 and the lower cone 3, the opening ends of the respective long slotted grooves 501 open, the outer diameter of the slips 5 increases, and the circular inner ends of the long slotted grooves 501 can avoid stress concentration.

[0048] Embodiment 6

[0049] Reference Figure 1 、 Figure 2 、 Figure 3 and Figure 4 , on the basis of Embodiment 1, a first embedded groove 502 is provided on the slips 5, the first embedded groove 502 is located at the upper edge of the slips 5, and emery anchor teeth are provided in the first embedded groove 502.

[0050] The emery anchor teeth installed in the first embedded groove 502 can enable the upper edge of the slips 5 to be anchored on the oil well casing.

[0051] Embodiment 7

[0052] Reference Figure 1 and Figure 2 , on the basis of Embodiment 6, a second embedded groove 503 is further provided on the slips 5, the second embedded groove 503 is located at the lower edge of the slips 5, and ceramic anchor bolts are provided in the second embedded groove 502.

[0053] The ceramic anchor bolts installed in the second embedded groove 503 can enable the lower edge of the slips 5 to be anchored on the oil well casing.

[0054] Embodiment 8

[0055] A method for fracturing and packing without dropping balls, which is implemented by using the fracturing and packing tool without dropping balls described in any of the above, includes the following steps: Step S001: Connect a tubing and a setting tool to the upper end of the mandrel 1 of the fracturing and packing tool without dropping balls, and lower the fracturing and packing tool without dropping balls to a preset position in the casing; Step S002: Push the release cap 7 and the upper cone 4 downward through the setting tool, drive the slips 5 to open, until the elastic claws 401 of the upper cone 4 are engaged and locked with the serrations 301 of the lower cone 3; Step S003: Pull the mandrel 1 upward through the setting tool, so that the threaded connection between the lower end of the mandrel 1 and the setting nut 2 is sheared, the setting nut 2 is separated from the mandrel 1, the shoulder 103 of the mandrel 1 contacts the upper end constriction of the release cap 7, continue to pull the mandrel 1 upward, and pull the mandrel 1 from the break groove 102 to complete the release; Step S004: Start pumping on the ground. Under the action of the fluid in the tubing, the mandrel 1 moves downward until the shoulder 103 contacts the upper cone 4, and the lower end of the mandrel 1 passes through the lower cone 3. At this time, the fracturing and packing tool without dropping balls is sealed.

[0056] Reference Figure 1 , in step S001, at this time, the fracturing and packing tool without dropping balls is not deformed, and its outer diameter is 6-10 mm smaller than the inner diameter of the casing.

[0057] Reference Figure 2 , in step S002, when starting to change the diameter, under the action of the setting tool, the release cap 7 drives the upper cone 4 to move downward, and the slips 5 climb along the outer cone surface of the upper cone 4 and the outer cone surface of the lower cone 3. The outer diameter of the slips 5 continuously increases until the serrations of the slips 5 are completely cut into the inner wall of the casing; at the same time, the sealing unit 6 climbs synchronously along the outer cone surface of the upper cone 4, and the outer diameter of the slips 5 continuously increases until the sealing unit 4 completely fits the inner wall of the casing. Finally, the elastic claws 401 at the lower part of the upper cone 4 are engaged and locked with the serrations 301 inside the lower cone 3.

[0058] Reference Figure 3 , in step S003, during the release action, the setting tool continues to act. The huge downward thrust first causes the threaded connection between the setting nut 2 and the lower end of the mandrel 1 to be damaged, and the entire thread is sheared. The setting nut 2 is separated from the fracturing and packing tool without dropping balls; the release nut 2 continues to move downward until the inner step of the release nut 2 contacts the step of the shoulder 103 outside the mandrel 1. The downward thrust continues to increase, causing the mandrel 1 to break at its break groove 102, thus completing the release.

[0059] Reference Figure 4 , in step S004, during the sealing action, start pumping on the ground. Under the action of the fluid, the mandrel 1 moves downward until the shoulder 103 outside it is completely in contact with the upper end of the upper cone 4. At the same time, the lower end of the mandrel 1 passes through the central hole of the lower cone 3. At this time, the tool is sealed, the well pressure rises, and normal fracturing construction begins.

[0060] As described above, this is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims. The components and structures not described in detail in this embodiment are well-known components and common structures or common means in this industry, and will not be described one by one here.

Claims

1. A ball-free fracturing packer tool, characterized in that, Comprising: A mandrel (1), a setting nut (2) is connected to the lower part of the mandrel (1), and a threaded connection part (101) is arranged at the upper end of the mandrel (1); a lower cone (3), the inner side of the lower end of the lower cone (3) is sleeved and fitted with the mandrel (1) and the setting nut (2), and a buttress thread (301) is arranged on the inner side of the upper end of the lower cone (3); an upper cone (4), the upper cone (4) is sleeved on the upper part of the mandrel (1), and an elastic claw (401) is arranged at the lower end of the upper cone (4); a slip (5), the lower part of the slip (5) is in contact with the conical surface of the lower cone (3), and the upper part is in contact with the conical surface of the upper cone (4), and a plurality of long slotted holes (501) are alternately arranged at the upper and lower edges of the slip (5); a sealing unit (6), the sealing unit (6) is located at the upper port of the slip (5), and the sealing unit (6) is sleeved on the outer conical surface of the upper cone (4); a releasing cap (7), the releasing cap (7) is sleeved on the mandrel (1), and the lower end of the releasing cap (7) abuts against the upper end of the upper cone (4); wherein, the above-mentioned components are all made of soluble metal materials; A pull-off groove (102) is arranged on the side wall below the threaded connection part (101); An axle shoulder (103) is further arranged on the side wall of the mandrel (1), and the upper cone (4) is sleeved on the mandrel (1) below the axle shoulder (103); The releasing cap (7) is sleeved on the outside of the axle shoulder (103), and a limiting reduced opening (701) is arranged at the upper end of the releasing cap (7), and the diameter of the limiting reduced opening (701) is smaller than the outer diameter of the axle shoulder (103); When pumping starts on the ground, under the action of the fluid in the tubing, the mandrel (1) moves downward until the axle shoulder (103) contacts the upper cone (4), and the lower end of the mandrel (1) passes through the lower cone (3). At this time, the no-ball-drop fracturing packer tool is sealed.

2. The ball-free fracturing packer tool according to claim 1, characterized in that, The opening end of the long slotted hole (501) is rectangular, and the inner end is circular.

3. The ball-free fracturing packer tool according to claim 1, characterized in that, A first embedded groove (502) is arranged on the slip (5), the first embedded groove (502) is located at the upper edge of the slip (5), and diamond abrasive anchor teeth are arranged in the first embedded groove (502); 4. The ball-free fracturing packer tool according to claim 3, characterized in that, A second embedded groove (503) is further arranged on the slip (5), the second embedded groove (503) is located at the lower edge of the slip (5), and ceramic anchor nails are arranged in the second embedded groove (502); 5. A ball-free fracturing packing method, implemented by using the ball-free fracturing packer tool according to any one of claims 1 to 4, characterized in that, Including the following steps: Step S001: Connect a tubing and a setting tool to the upper end of the mandrel of the no-ball-drop fracturing packer tool, and lower the no-ball-drop fracturing packer tool to a preset position in the casing; Step S002: Push the releasing cap and the upper cone downward through the setting tool, drive the slips to open until the elastic claws of the upper cone are engaged and locked with the buttress threads of the lower cone; Step S003: Pull up the mandrel through the setting tool, so that the threaded connection between the lower end of the mandrel and the setting nut is sheared, the setting nut is separated from the mandrel, the axle shoulder of the mandrel contacts the upper reduced opening end of the releasing cap, and continue to pull up the mandrel to break the mandrel from the pull-off groove, thereby completing the release. Step S004: Start the pump on the ground. Under the action of the fluid in the tubing, the mandrel moves downward until the shoulder contacts the upper cone, and the lower end of the mandrel passes through the lower cone. At this time, the ball-free fracturing packer tool is sealed.

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