Prestressed cementing anchor

Abstract

The present invention relates to the field of cementing tools, and in particular to a prestressed cementing anchor, which aims to alleviate the technical problem of low anchoring firmness of the anchor in the related technology. The prestressed cementing anchor includes an expansion assembly and an anchoring assembly, wherein the expansion assembly includes an isolation sleeve, an expansion mechanism and a turbine mechanism, wherein one end of the isolation sleeve is fixedly connected to the anchoring assembly and is also connected to the anchoring assembly, the expansion mechanism is rotatably connected to the other end of the isolation sleeve, and the turbine mechanism is arranged in the isolation sleeve and is connected to the expansion mechanism through magnetic transmission, so as to be able to drive the expansion mechanism to rotate around the axis of the isolation sleeve under the starting condition. The anchor can be driven by hydraulic power to start the turbine mechanism, thereby driving the expansion mechanism to rotate, so as to remove the virtual mud cake of the anchoring section, and expand a step of a certain size on the well wall, so that the extension angle of the anchor claw of the anchor assembly is improved, which can effectively avoid the problem of difficulty in the insertion of the anchor claw in the hard formation and the loose anchoring of the anchor claw in the soft formation after extension.

Description

Technical Field

[0001] The invention relates to the field of cementing tools, and in particular to a prestressed cementing anchor. Background Art

[0002] At present, the technology commonly used in heavy oil production at home and abroad is prestressed cementing technology, among which casing anchor prestressed cementing technology is one of the main technologies for preventing and controlling casing damage in heavy oil thermal production wells. It is simple to operate and easy to use.

[0003] However, with the continuous expansion of field applications, more and more problems are exposed in casing anchor prestressed cementing. As a cementing tool, the anchor claws of the anchor cannot be firmly anchored in the well wall, which will affect the fixing firmness of the casing in the well. Once the casing cannot be firmly installed in the well, the quality of cementing will be reduced, the success rate of prestressed cementing will be reduced, and the risk of casing loss will increase. Summary of the invention

[0004] The object of the present invention is to provide a prestressed cementing ground anchor to alleviate the technical problem of low anchoring firmness of the ground anchor in the related art.

[0005] In order to solve the above technical problems, the technical solution provided by the present invention is:

[0006] The prestressed cementing ground anchor provided by the present invention comprises: an expansion assembly and an anchoring assembly, wherein the expansion assembly comprises an isolation sleeve, an expansion mechanism and a turbine mechanism, wherein one end of the isolation sleeve is fixedly connected to the anchoring assembly and is also connected to the anchoring assembly, the expansion mechanism is rotatably connected to the other end of the isolation sleeve, and the turbine mechanism is arranged in the isolation sleeve and is connected to the expansion mechanism through magnetic transmission so as to be able to drive the expansion mechanism to rotate around the axis of the isolation sleeve under starting conditions.

[0007] Further, the turbine mechanism includes a turbine rotor and a plurality of groups of first magnetic blocks;

[0008] The turbine rotor is coaxially arranged with the isolation sleeve and is also rotationally matched with the isolation sleeve;

[0009] Along the axial direction of the turbine rotor, a plurality of groups of the first magnetic blocks are distributed at intervals, and in each group, a plurality of the first magnetic blocks are distributed equidistantly on the side wall of the turbine rotor along the circumferential direction of the turbine rotor;

[0010] The diameter expansion assembly further includes a transmission mechanism, which includes a non-magnetic shell and a second magnetic block embedded in the non-magnetic shell;

[0011] The non-magnetic housing is rotatably connected to the isolation sleeve and can rotate around the axis of the isolation sleeve;

[0012] The diameter expansion mechanism is fixedly connected to the non-magnetic housing;

[0013] The second magnetic block corresponds to the first magnetic block one by one, and the magnetic poles of the two opposite ends are opposite.

[0014] Furthermore, the turbine mechanism further comprises a turbine stator, which is coaxially arranged with the isolation sleeve and fixedly connected with the isolation sleeve;

[0015] The inner wall of the isolation sleeve protrudes to form a boss;

[0016] The turbine rotor is located between the boss and the turbine stator, and both ends thereof are rotatably matched with the isolation sleeve through a ball bearing;

[0017] The two ball bearings are respectively in contact with the boss and the turbine stator.

[0018] Furthermore, the non-magnetic shell is sleeved on the isolation sleeve, and a first annular groove extending around its own axis is provided on the inner wall of the non-magnetic shell;

[0019] The outer wall of the isolation sleeve is provided with a second annular groove extending around its own axis, the second annular groove is opposite to the first annular groove, and the space between the two is filled with steel balls, and the spherical surface of the steel balls is matched with the groove surfaces of the two.

[0020] Furthermore, the diameter expansion mechanism includes an expansion head and an eccentric blade;

[0021] The expansion head is in the shape of a tube with two ends open, and one end of the expansion head is sleeved on the non-magnetic shell and fixedly connected to the non-magnetic shell;

[0022] The eccentric blade is fixed to the outer wall of the expansion head.

[0023] Further, the end face of the other end of the expanding head is an arc-shaped end face, and the arc-shaped end face is composed of a first arc surface and a second arc surface, and the first arc surface and the second arc surface are both connected to the side of the expanding head, and the diameter of the first arc surface is larger than the outer diameter of the expanding head, and the diameter of the second arc surface is smaller than the outer diameter of the expanding head;

[0024] And / or, the expanding head is provided with a circulation channel running through its side wall, the circulation channel is located on the side of the eccentric blade away from the non-magnetic shell, and one end of the circulation channel is connected to the inner cavity of the expanding head, and the other end extends in a direction close to the eccentric blade.

[0025] Furthermore, the anchoring assembly includes a body, a piston, a spring, an anchor claw and a connecting rod;

[0026] The main body is in a tubular shape with both ends open and is fixedly connected to the isolation sleeve;

[0027] The piston is also in the shape of a tube with both ends open, and is disposed in the body, and is fixedly connected to the body through shear pins, and is also surrounded by the body to form an annular cavity;

[0028] The spring is in the annular cavity and sleeved on the piston, and one end of the spring is connected to the piston and the other end is connected to the body. The spring makes the piston have a tendency to slide away from the isolation sleeve.

[0029] The fluke is hinged to the body and does not protrude from the outer wall of the body;

[0030] One end of the connecting rod is hinged to the fluke, and the other end is hinged to the piston. The connecting rod can drive the fluke to protrude from the outer wall of the body when the piston slides toward the spacer sleeve.

[0031] Furthermore, a retaining ring is embedded on the inner wall of the body, and the retaining ring is located on a side of the piston away from the isolation sleeve;

[0032] The anchor assembly further comprises a float valve, wherein the float valve comprises a valve seat and a hollow float ball;

[0033] The valve seat is also in the shape of a tube with both ends open, and its two ends are respectively in contact with the end faces of the retaining ring and the piston;

[0034] Along the axial direction of the valve seat, the inner cavity of the valve seat is divided into a flow passage and a flow chamber in sequence, one end of the flow chamber is connected to the flow passage, and the other end is connected to the piston;

[0035] The hollow floating ball is movably arranged in the flow cavity, and its outer diameter is larger than the aperture of the flow channel.

[0036] Furthermore, the float valve also includes a baffle, which is located in the flow chamber, with its side fixedly connected to the inner wall of the valve seat, and its end away from the hollow float abutting against the end surface of the piston;

[0037] The baffle plate is provided with a plurality of through holes extending along its own axial direction, and the total flow area of ​​the plurality of through holes is 1.5 times the flow area of ​​the flow passage.

[0038] Furthermore, the inner cavity of the piston includes a main flow channel and three side flow channels, all of which have circular cross-sections;

[0039] The main flow channel is coaxially arranged with the main body;

[0040] The three side flow channels are distributed around the axis of the main flow channel at intervals of 120°, and all partially overlap with the main flow channel.

[0041] In summary, the technical effects that can be achieved by the prestressed cementing anchor provided by the present invention are:

[0042] The prestressed cementing anchor comprises an expansion assembly and an anchoring assembly. After the tool is put into the well, the turbine mechanism can be started by hydraulic drive, thereby driving the expansion mechanism to rotate. During the rotation process, the expansion mechanism will remove the virtual mud cake in the anchoring section and expand a step of a certain size on the well wall. After the cementing is pressed, the anchoring assembly is started under pressure drive. Since the space is larger after the hole is expanded, the extension angle of the anchor claw of the anchoring assembly is improved, so that the anchoring effect is better, which can effectively avoid the problem of difficulty in the anchor claw in the hard formation and the loose anchoring after the anchor claw in the soft formation is extended. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0044] Figure 1 A cross-sectional view of a prestressed cementing anchor provided by an embodiment of the present invention;

[0045] Figure 2 For the piston Figure 1 Sectional view in the AA direction;

[0046] Figure 3 A top view of a baffle provided in an embodiment of the present invention.

[0047] Icon: 100-isolation sleeve; 110-boss;

[0048] 200-diameter expansion mechanism; 210-diameter expansion head; 220-eccentric blade; 211-first arc surface; 212-second arc surface; 213-circulation channel;

[0049] 300-turbine mechanism; 310-turbine rotor; 320-first magnetic block; 330-turbine stator; 340-ball bearing;

[0050] 400-transmission mechanism; 410-non-magnetic housing; 420-second magnetic block; 430-steel ball; 440-plug;

[0051] 500-body; 600-piston; 700-spring; 800-anchor claw; 900-connecting rod; 1000-shear pin; 1100-retaining ring;

[0052] 1200-float valve; 1210-valve seat; 1220-hollow float ball; 1230-baffle; 1211-flow channel; 1212-flow cavity; 1231-through hole;

[0053] 1300-Friction bearings. DETAILED DESCRIPTION

[0054] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0055] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0056] Some embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.

[0057] As a cementing tool, the ground anchor may not be firmly anchored in the well wall. This will affect the fixing firmness of the casing in the well. Once the casing cannot be firmly installed in the well, the quality of cementing will be reduced, the success rate of prestressed cementing will be reduced, and the risk of casing loss will increase.

[0058] In view of this, the present invention provides a prestressed cementing anchor, including an expansion assembly and an anchoring assembly, the expansion assembly including an isolation sleeve 100, an expansion mechanism 200 and a turbine mechanism 300, wherein one end of the isolation sleeve 100 is fixedly connected to the anchoring assembly and is also connected to the anchoring assembly, the expansion mechanism 200 is rotatably connected to the other end of the isolation sleeve 100, the turbine mechanism 300 is arranged in the isolation sleeve 100, and is connected to the expansion mechanism 200 by magnetic transmission, so as to be able to drive the expansion mechanism 200 to rotate around the axis of the isolation sleeve 100 under starting conditions.

[0059] The prestressed cementing anchor comprises an expansion assembly and an anchoring assembly. After the tool is put into the well, the turbine mechanism 300 can be started by hydraulic drive, thereby driving the expansion mechanism 200 to rotate. The expansion mechanism 200 will remove the virtual mud cake of the anchoring section during the rotation process and expand a step of a certain size on the well wall. After the cementing is pressed, the anchoring assembly is started under pressure drive. Since the space is larger after the eye is expanded, the extension angle of the anchor claw 800 of the anchoring assembly is improved, so that the anchoring effect is better, which can effectively avoid the problem that the anchor claw 800 is difficult to bite into the hard formation and the anchor claw 800 is not firmly anchored after extension in the soft formation.

[0060] The following combination Figures 1 to 3 The structure and shape of the prestressed cementing anchor provided in this embodiment are described in detail:

[0061] Regarding the turbine mechanism 300, specifically:

[0062] refer to Figure 1 The turbine mechanism 300 includes a turbine stator 330 and a turbine rotor 310; the turbine stator 330 is threadedly connected to the isolation sleeve 100; the inner wall of the isolation sleeve 100 protrudes to form a boss 110, and the boss 110 is flush with the bottom end of the isolation sleeve 100; the turbine rotor 310 is rotatably matched with the isolation sleeve 100 through ball bearings 340 respectively arranged at the upper and lower ends thereof, and the upper end of the turbine rotor 310 does not contact the bottom end of the turbine stator 330, the upper ball bearing 340 abuts against the bottom end of the turbine stator 330, the lower end of the turbine rotor 310 does not contact the top surface of the boss 110, and the lower ball bearing 340 abuts against the top surface of the boss 110.

[0063] In accordance with the above, the turbine rotor 310 and the diameter expansion mechanism 200 are magnetically transmitted through the transmission mechanism 400. Specifically, a plurality of groups of first magnetic blocks 320 are provided on the turbine rotor 310, and the plurality of groups of first magnetic blocks 320 are spaced apart along the axial direction of the turbine rotor 310. In each group, a plurality of first magnetic blocks 320 are equally spaced along the circumference of the turbine rotor 310 and distributed on the side wall of the turbine rotor 310; the transmission mechanism 400 includes a non-magnetic housing 410 and a second magnetic block 420 embedded in the non-magnetic housing 410, the non-magnetic housing 410 is rotatably connected to the isolation sleeve 100 and can rotate around the axis of the isolation sleeve 100, the diameter expansion mechanism 200 is fixedly connected to the non-magnetic housing 410, the second magnetic block 420 corresponds to the first magnetic block 320 one by one, and the magnetic poles of the opposite ends of the two are opposite.

[0064] Continuing with the above, the non-magnetic shell 410 is sleeved on the isolation sleeve 100, and a first annular groove extending around its own axis is provided on its inner wall. Optionally, two first annular grooves are provided, and the two first annular grooves are distributed on the upper and lower sides of the second magnetic block 420; a second annular groove extending around its own axis is provided on the outer wall of the isolation sleeve 100, and the second annular groove corresponds to the first annular groove one by one, and the two are arranged oppositely to enclose a cavity with a circular cross section; the cavity is filled with steel balls 430, and the diameter of the steel balls 430 is equal to the diameter of the cavity cross section. In this design, the rotation connection between the non-magnetic shell 410 and the isolation sleeve 100 is realized, and the axial movement of the non-magnetic shell 410 in the isolation sleeve 100 is restricted.

[0065] It should be added that the turbine rotor 310, the first magnetic block 320, the isolation sleeve 100, the non-magnetic shell 410 and the second magnetic block 420 constitute a magnetic coupling mechanism, which is a prior art, and its magnetic transmission is well known to those skilled in the art, so the transmission principle of the magnetic coupling mechanism and the specific arrangement of the magnetic blocks are not described here. It should also be added that a through hole is provided on the side wall of the non-magnetic shell 410, and the through hole corresponds to the first annular groove one by one; a plug 440 is inserted into the through hole, and the plug 440 is fixedly connected to the non-magnetic shell 410 and is also in contact with the steel ball. Optionally, the plug 440 is welded to the non-magnetic shell 410, or threaded. Through this design, the steel ball can be filled into the first annular groove from the through hole, and the operation is convenient.

[0066] During construction, liquid is pumped into the wellhead to establish a circulation. When the fluid flows downward through the turbine mechanism 300, the turbine rotor 310 rotates under the drive of the fluid, and synchronously drives the first magnetic block 320 thereon to rotate. At this time, under the magnetic force of the first magnetic block 320 and the second magnetic block 420, the non-magnetic shell 410 rotates synchronously with the second magnetic block 420, and drives the diameter expansion mechanism 200 to rotate to expand the diameter.

[0067] Regarding the diameter expansion mechanism 200, specifically:

[0068] refer to Figure 1 The expansion mechanism 200 includes an expansion head 210; the expansion head 210 is in a tubular shape with both ends open, and its upper end is sleeved on the non-magnetic shell 410 and is threadedly connected to the non-magnetic shell 410. A friction bearing 1300 is arranged between the expansion head 210 and the isolation sleeve 100. The upper end surface of the friction bearing 1300 abuts against the bottom end of the isolation sleeve 100, and the lower end surface abuts against the expansion head 210. The middle part of the outer wall of the expansion head 210 protrudes to form a step, that is, an eccentric blade 220. The longitudinal section of the eccentric blade 220 is an isosceles trapezoid, and hard alloy particles are welded on the surface. When the expansion head 210 rotates with the non-magnetic shell 410, the eccentric blade 220 rotates synchronously around the axis of the expansion head 210 to expand the wellbore.

[0069] Continue to refer Figure 1 In one embodiment of the present application, the lower end face of the enlarging head 210 is an arc-shaped end face, which is composed of a first arc surface 211 and a second arc surface 212. The first arc surface 211 and the second arc surface 212 are both connected to the side of the enlarging head 210, and the diameter of the first arc surface 211 is greater than the outer diameter of the enlarging head 210, and the diameter of the second arc surface 212 is smaller than the outer diameter of the enlarging head 210. In another embodiment, the enlarging head 210 is provided with a circulation channel 213 penetrating its side wall, the circulation channel 213 is inclined and is located below the eccentric blade 220, one end of the circulation channel 213 is connected to the inner cavity of the enlarging head 210, and the other end extends obliquely upward and is close to the bottom end of the eccentric blade 220. In other embodiments, the lower end face of the enlarging head 210 is an arc-shaped end face, and the design of the arc-shaped end face is the same as above; the enlarging head 210 is provided with a circulation channel 213 penetrating its side wall, and the design of the circulation channel 213 is the same as above.

[0070] The advantage of the above design is that the expansion head 210 has the functions of circulation, guiding and expansion; circulation means that the liquid in the prestressed cementing anchor can circulate from the inside of the pipe string to the outside of the pipe string through the inner cavity of the expansion head 210 and the circulation channel 213, and the liquid flowing through the circulation channel 213 can effectively flush the eccentric blade 220 and the expansion section of the well wall.

[0071] In the above, guiding means that the arc-shaped end surface of the expansion head 210 can be forced to rotate and change direction under the action of external force to pass through obstacles. Figure 1 As shown, during the lowering process of the prestressed cementing anchor, if the first curved surface 211 contacts an obstacle, the anchor will swing to the right as it continues to be lowered, thereby changing direction and passing through the obstacle; if the second curved surface 212 contacts the obstacle, the obstacle will exert a horizontal lateral resistance along the tangent direction of the second curved surface 212 on the second curved surface 212 as it continues to be lowered, and under the action of this force, the expansion head 210 rotates, causing the first curved surface 211 to contact the obstacle, and then the anchor swings to the right and passes through the obstacle. It should also be added here that when the anchor encounters obstacles during lowering, it can also be rotated by applying external force to the anchor, so that the first curved surface 211 contacts the obstacle, or liquid can be injected into the anchor to establish circulation, and the magnetic coupling mechanism is started through the turbine rotor 310, thereby driving the expansion head 210 to rotate, so that the first curved surface 211 contacts the obstacle.

[0072] Continuing with the above, the expansion refers to the deflection of the eccentric blade wing 220 welded with hard alloy during the rotation process to expand the wellbore. Specifically, since the eccentric blade wing 220 is located in a part of the expansion head 210, the center of gravity of the expansion head 210 deviates from its axis, so that the expansion head 210 is subjected to uneven force during rotation, forming an eccentric rotation. In this way, the movement of the eccentric blade wing 220 is also an eccentric rotation, so that the wellbore can be effectively expanded.

[0073] Regarding the anchor assembly, specifically:

[0074] refer to Figure 1 The anchor assembly includes a body 500, a piston 600, a spring 700, an anchor claw 800 and a connecting rod 900; the body 500 is in a tubular shape with both ends open, and its lower end is threadedly connected to the upper end of the isolation sleeve 100, and a receiving hole is provided on its side wall; the piston 600 is also in a tubular shape with both ends open, and is arranged in the body 500, and is fixedly connected to the body 500 through a shear pin 1000, and is also surrounded by the body 500 to form an annular cavity; optionally, three shear pins 1000 are provided, and the three shear pins 1000 are spaced 1 / 4" around the axis of the piston 600. 20° distribution; the spring 700 is in the annular cavity and is sleeved on the piston 600, and its upper end is connected to the piston 600, and the lower end is connected to the body 500, and the spring 700 makes the piston 600 have a tendency to slide upward; the upper end of the connecting rod 900 is connected to the piston 600 through the first rotating pin, and the lower end is connected to the middle of the fluke 800 through the second rotating pin; the fluke 800 is in the accommodating hole, and its lower end is connected to the body 500 through the third rotating pin, and the bottom end is an arc surface, which is concentric with the third rotating pin and also contacts with the bottom wall of the accommodating hole.

[0075] Preferably, Figure 2 As shown, the inner cavity of the piston 600 includes a main channel and three side channels, all of which are circular in cross section; the main channel is coaxially arranged with the body 500; the three side channels are distributed around the axis of the main channel at intervals of 120° and partially overlap with the main channel. With this design, the inner cavity of the piston 600 forms a special-shaped channel structure, which increases the flow area and can avoid premature start-up of the piston 600 due to the interception pressure drop.

[0076] When applied, combine Figure 1 As shown, in the initial state of the anchoring assembly, the anchor claw 800 does not protrude from the outer wall of the body 500; after a cavity with a relatively large diameter is created at the position where the well wall needs to be anchored, the anchoring assembly is lowered to the cavity creation position and cementing begins; after the cementing is completed, a pressure plug is placed at the wellhead to hold the pressure, and when the pressure reaches a preset value, the shear pin 1000 is sheared off, the piston 600 slides down, and compresses the spring 700, and at the same time, the piston 600 drives the connecting rod 900 to swing, and the anchor claw 800 is stretched open. Since the diameter of the cavity is larger after the expansion, the extension angle of the anchor claw 800 is correspondingly larger; then the pipe string is lifted up, so that the anchor claw 800 is hung on the cavity step and stretched with a certain tension to complete the construction.

[0077] As mentioned above, when the anchoring result does not meet the standard, the pipe string is lowered. At this time, under the action of the restoring force of the spring 700, the piston 600 slides up and drives the anchor claw 800 to retract through the connecting rod 900. Then the pipe string can be moved to change the anchoring position, and then the pressure is held and pulled again.

[0078] Furthermore, in order to prevent the liquid in the prestressed cementing anchor from returning upward, a float valve 1200 is provided in the body 500. Specifically, the float valve 1200:

[0079] refer to Figure 1 A retaining ring 1100 is embedded on the inner wall of the body 500, and the retaining ring 1100 is located above the piston 600. The float valve 1200 includes a valve seat 1210, a hollow floating ball 1220 and a baffle 1230; the valve seat 1210 is in a tubular shape with both ends open, and its two ends are respectively abutted against the top of the retaining ring 1100 and the piston 600; along the axial direction of the valve seat 1210, from top to bottom, the inner cavity of the valve seat 1210 is divided into a flow channel 1211 and a flow chamber 1212 in sequence; the hollow floating ball 1220 is movably arranged in the flow chamber 1212, and its outer diameter is larger than the aperture of the flow channel 1211; the baffle 1230 is threadedly connected to the valve seat 1210, and the two are also welded, the bottom surface of the baffle 1230 is abutted against the top of the piston 600, and the baffle 1230 is provided with a plurality of through holes 1231 extending along its own axial direction, such as Figure 3 As shown, the diameter of the through hole 1231 is smaller than the diameter of the hollow float 1220 .

[0080] With the above design, when the liquid flows to the float valve 1200, it impacts the hollow float ball 1220 downward, and flows to the piston 600 through the flow channel 1211, the flow chamber 1212 and the through hole 1231 in sequence; when the mud returns, the float ball blocks the flow channel 1211, so that the flow channel 1211 is not connected with the flow chamber 1212, thereby preventing the mud from flowing in the opposite direction.

[0081] It should be added here that a sealing ring is embedded in the outer wall of the valve seat 1210, and the sealing ring abuts against the inner wall of the body 500, so that the valve seat 1210 and the body 500 are sealed. With this design, when the pressure is held by the rubber plug, pressure release can be prevented, ensuring that the shear pin 1000 can be sheared. In addition, sealing rings are also embedded in the outer walls of the upper and lower ends of the piston 600, respectively, and the two sealing rings are located on both sides of the spring 700 and the anchor claw 800, so that the piston 600 and the body 500 are sealed.

[0082] Preferably, the hollow float 1220 is a double-layer hollow ball, the inner layer of which is a hollow metal ball and the outer layer is vulcanized nitrile rubber. With this design, the buoyancy of the hollow float 1220 is lower than the density of the mud, and when the mud flows upward, the flow channel 1211 can be effectively blocked.

[0083] Preferably, the surface of the baffle 1230 is sprayed with tungsten carbide to resist cyclic erosion damage. A porous flexible gasket is provided on the upper surface of the baffle 1230, and the holes on the porous flexible gasket correspond to the through holes 1231 one by one. The porous flexible gasket and the baffle 1230 can be bonded, but are not limited to the bonding fixing method, such as vulcanization. The porous flexible gasket can be rubber or an elastomer similar to rubber, which can alleviate the impact force between the hollow float 1220 and the baffle 1230.

[0084] Preferably, combined with Figure 1 and Figure 3 As shown, the total flow area of ​​the plurality of through holes 1231 is 1.5 times the flow area of ​​the flow channel 1211; the inner wall of the piston 600 above the special-shaped channel and the wall of the flow chamber 1212 enclose a cavity, and the longitudinal section of the cavity tends to be elliptical. With this design, when the fluid enters the cavity from the flow channel 1211, the flow velocity changes, and when it flows from the cavity to the lower flow channel through the through hole 1231, it forms a cut-off flow, so that the fluid excites vibration, and the vibration can eliminate bubbles in the cement, increase the density of the cement, and thus improve the cementing quality.

[0085] The working process of the prestressed cementing anchor provided in this embodiment is as follows:

[0086] During construction, the prestressed cementing anchor is connected to the wellbore string, and the anchor is lowered to the designed position, and then the pipe string is lifted up a certain distance, and liquid is pumped into the wellhead to establish circulation; the turbine rotor 310 of the turbine mechanism 300 rotates under the drive of the fluid, and further, under the magnetic force of the first magnetic block 320 and the second magnetic block 420, the non-magnetic shell 410 rotates and synchronously drives the expansion head 210 to rotate. At the same time, the pipe string is appropriately lowered or lifted, and the wellbore is trimmed, scraped and expanded by the rotating eccentric blade 220, and when necessary A cavity with a relatively large diameter is created at the location to be anchored; after the cavity is created, the anchor assembly is lowered to the cavity creation location and cementing is started; after cementing is completed, a pressure plug is placed at the wellhead to the upper end of the valve seat 1210, and then the pressure is held to cut the shear pin 1000, and the valve seat 1210 and the piston 600 move axially downward under the pressure, thereby driving the connecting rod 900 to swing and open the anchor claw 800. Since the cavity diameter is larger after the expansion, the extension angle of the anchor claw 800 is correspondingly larger; then the pipe string is lifted to make the anchor claw 800 hang on the cavity step and stretch a certain tension to complete the construction.

[0087] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A prestressed cementing anchor, characterized in that: include: An expansion assembly and an anchoring assembly, wherein the expansion assembly comprises an isolating sleeve (100), an expansion mechanism (200) and a turbine mechanism (300), wherein one end of the isolating sleeve (100) is fixedly connected to the anchoring assembly and is also arranged in communication with the anchoring assembly, the expansion mechanism (200) is rotatably connected to the other end of the isolating sleeve (100), and the turbine mechanism (300) is arranged in the isolating sleeve (100) and is connected to the expansion mechanism (200) through magnetic transmission, so as to be able to drive the expansion mechanism (200) to rotate around the axis of the isolating sleeve (100) under a starting condition; The turbine mechanism (300) comprises a turbine rotor (310) and a plurality of groups of first magnetic blocks (320); The turbine rotor (310) is coaxially arranged with the isolation sleeve (100) and is also rotationally matched with the isolation sleeve (100); Along the axial direction of the turbine rotor (310), a plurality of groups of the first magnetic blocks (320) are distributed at intervals, and in each group, a plurality of the first magnetic blocks (320) are distributed equidistantly on the side wall of the turbine rotor (310) along the circumferential direction of the turbine rotor (310); The diameter expansion assembly further comprises a transmission mechanism (400), wherein the transmission mechanism (400) comprises a non-magnetic housing (410) and a second magnetic block (420) embedded in the non-magnetic housing (410); The non-magnetic housing (410) is rotatably connected to the isolation sleeve (100) so as to be rotatable around the axis of the isolation sleeve (100); The diameter expansion mechanism (200) is fixedly connected to the non-magnetic housing (410); The second magnetic block (420) corresponds to the first magnetic block (320) one by one, and the magnetic poles of the two opposite ends are opposite; The diameter expansion mechanism (200) comprises a diameter expansion head (210) and an eccentric blade (220); The expanding head (210) is in the shape of a tube with two ends open, and one end of the expanding head (210) is sleeved on the non-magnetic shell (410) and fixedly connected to the non-magnetic shell (410); The eccentric blade (220) is fixed to the outer wall of the diameter expanding head (210).

2. The prestressed cementing anchor according to claim 1, characterized in that: The turbine mechanism (300) further comprises a turbine stator (330), wherein the turbine stator (330) is coaxially arranged with the isolation sleeve (100) and is fixedly connected to the isolation sleeve (100); The inner wall of the isolation sleeve (100) is protruded to form a boss (110); The turbine rotor (310) is located between the boss (110) and the turbine stator (330), and both ends thereof are rotatably matched with the isolation sleeve (100) via a ball bearing (340); The two ball bearings (340) are respectively in contact with the boss (110) and the turbine stator (330).

3. The prestressed cementing anchor according to claim 1, characterized in that: The non-magnetic shell (410) is sleeved on the isolation sleeve (100), and a first annular groove extending around its own axis is provided on the inner wall of the non-magnetic shell (410); The outer wall of the isolation sleeve (100) is provided with a second annular groove extending around its own axis, the second annular groove is opposite to the first annular groove, and the space between the two is filled with steel balls (430), and the spherical surface of the steel balls (430) is adapted to the groove surfaces of the two.

4. The prestressed cementing anchor according to claim 1, characterized in that: The end surface of the other end of the expanding head (210) is an arc-shaped end surface, and the arc-shaped end surface is composed of a first arc surface (211) and a second arc surface (212), and the first arc surface (211) and the second arc surface (212) are both connected to the side surface of the expanding head (210), and the diameter of the first arc surface (211) is greater than the outer diameter of the expanding head (210), and the diameter of the second arc surface (212) is smaller than the outer diameter of the expanding head (210); And / or, the expanding head (210) is provided with a circulation channel (213) penetrating through its side wall, the circulation channel (213) is located on the side of the eccentric blade (220) away from the non-magnetic shell (410), and one end of the circulation channel (213) is connected to the inner cavity of the expanding head (210), and the other end extends in a direction close to the eccentric blade (220).

5. The prestressed cementing anchor according to any one of claims 1 to 4, characterized in that: The anchoring assembly comprises a body (500), a piston (600), a spring (700), an anchor claw (800) and a connecting rod (900); The main body (500) is in a tubular shape with both ends open, and is fixedly connected to the isolation sleeve (100); The piston (600) is also in the shape of a tube with both ends open, and is disposed in the body (500). It is fixedly connected to the body (500) via a shear pin (1000), and is enclosed with the body (500) to form an annular cavity. The spring (700) is located in the annular cavity and is sleeved on the piston (600), and one end of the spring is connected to the piston (600) and the other end is connected to the body (500). The spring (700) causes the piston (600) to have a tendency to slide away from the isolation sleeve (100); The fluke (800) is hinged to the body (500) and does not protrude from the outer wall of the body (500); One end of the connecting rod (900) is hinged to the fluke (800), and the other end is hinged to the piston (600). When the piston (600) slides toward the isolation sleeve (100), the connecting rod (900) can drive the fluke (800) to protrude from the outer wall of the body (500).

6. The prestressed cementing anchor according to claim 5, characterized in that: A retaining ring (1100) is embedded on the inner wall of the body (500), and the retaining ring (1100) is located on a side of the piston (600) away from the isolation sleeve (100); The anchor assembly further comprises a float valve (1200), wherein the float valve (1200) comprises a valve seat (1210) and a hollow float ball (1220); The valve seat (1210) is also in the shape of a tube with both ends open, and its two ends are respectively in contact with the end surfaces of the retaining ring (1100) and the piston (600); Along the axial direction of the valve seat (1210), the inner cavity of the valve seat (1210) is divided into a flow passage (1211) and a flow chamber (1212) in sequence, one end of the flow chamber (1212) is connected to the flow passage (1211), and the other end is connected to the piston (600); The hollow floating ball (1220) is movably disposed in the flow chamber (1212), and its outer diameter is larger than the aperture of the flow channel (1211).

7. The prestressed cementing anchor according to claim 6, characterized in that: The float valve (1200) further comprises a baffle (1230), wherein the baffle (1230) is located in the flow chamber (1212), a side surface of the baffle is fixedly connected to the inner wall of the valve seat (1210), and an end of the baffle away from the hollow float ball (1220) abuts against an end surface of the piston (600); The baffle (1230) is provided with a plurality of through holes (1231) extending along its own axial direction, and the total flow area of ​​the plurality of through holes (1231) is 1.5 times the flow area of ​​the flow channel (1211).

8. The prestressed cementing anchor according to claim 5, characterized in that: The inner cavity of the piston (600) comprises a main flow channel and three side flow channels, all of which have circular cross-sections; The main flow channel is coaxially arranged with the main body (500); The three side flow channels are distributed around the axis of the main flow channel at intervals of 120°, and all partially overlap with the main flow channel.

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