CN117662043A - Liner hanger with enhanced locking means and method of operation thereof - Google Patents

Abstract

The invention discloses a liner hanger with an enhanced locking device and a method of operating the same. The liner hanger comprises: a hanger body; the locking assembly, the floating cone locking assembly, the driving assembly, the fixed slip assembly and the hanging slip assembly are sleeved outside the hanger body in sequence; the pressure holding mechanism is arranged inside the hanger body. When the pressure-building mechanism is not building, the locking assembly, the floating cone locking assembly, the driving assembly, the fixed slip assembly and the hanging slip assembly are all locked. When the pressure is built up at one stage, the locking assembly is unlocked, and then the floating cone locking assembly moves upwards to unlock. When the pressure is built up in the second stage of the pressure building mechanism, the driving component is activated, and the hanging slip assembly is unlocked and hung in a sitting mode. The stationary seat of the stationary slip assembly may then be unlocked and effected. The liner hanger provided by the invention prevents all components from being started before the liner hanger is unlocked and achieves smooth drive of the seat after the liner hanger reaches depth.

Description

Liner hanger with enhanced locking means and method of operation thereof

Technical Field

The invention belongs to the field of oil and natural gas cementing tools, and particularly relates to a liner hanger with an enhanced locking device and an operation method thereof.

Background

The tail pipe string is the string of pipes installed at the lowermost end of the casing in the well. A hanger is typically used to connect the liner string to the casing in a hanging manner and above the formation for oil recovery.

In recent years, along with the rapid development of drilling technology, the drilling depth is continuously increased, the well temperature is also continuously increased, and the conditions of coexistence of high temperature, high pressure and multiple pressure systems are generated. The safety of going into the well, the reliability of sitting and hanging, the sealing capability, the temperature resistance capability and the like of the tail pipe hanger are all provided with higher requirements. Conventional liner hangers currently have difficulty meeting increasingly complex field requirements and have problems in use. The main manifestations are: in the application of highly deviated wells and deep wells, the reliability of the hanger for hanging and releasing is low; the tail pipe and the hanger are difficult to smoothly drop to the design position, repeatedly lifted and lowered, exposed parts such as slips and the like are easy to bump off, and larger accidents are caused; the pressure transmission holes in the connecting pipe of the hanger and the hydraulic cylinder are in an exposed state, so that the hydraulic cylinder can act as long as pressure is generated in the pipe, the hanger is further sat and hung in advance, and great trouble is brought to construction.

To address this problem, it is desirable to design a liner hanger with an enhanced locking arrangement having one or more enhanced locking assemblies to prevent actuation of all of the assemblies until the liner hanger is unlocked and to provide a smooth drive ride after the liner hanger has reached its depth.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provides a liner hanger with an enhanced locking device.

The technical scheme adopted by the invention is as follows:

according to a first aspect of the present invention there is provided a liner hanger with an enhanced locking device comprising: the hanger comprises a hanger body, wherein the hanger body is provided with a first pressure transmission hole and a second pressure transmission hole; the locking assembly, the floating cone locking assembly, the driving assembly, the fixed slip assembly and the hanging slip assembly are sleeved outside the hanger body in sequence from top to bottom, wherein a part of the floating cone locking assembly is positioned between the locking assembly and the hanger body, a first pressure holding cavity in fluid communication with the first pressure transmission hole is formed between the part of the floating cone locking assembly and the locking assembly, and a second pressure holding cavity in fluid communication with the second pressure transmission hole is formed between the driving assembly and the hanger body; the pressure holding mechanism is arranged inside the hanger body. When the pressure-building mechanism is not building, the locking assembly, the floating cone locking assembly, the driving assembly, the fixed slip assembly and the hanging slip assembly are all locked on the hanger body, wherein the locking assembly is connected with the floating cone locking assembly; when the first pressure-holding cavity holds pressure, the locking assembly is disconnected with the floating cone locking assembly to unlock the locking assembly, the locking assembly moves upwards relative to the hanger body, after the locking assembly moves upwards for a certain distance, the locking assembly and the floating cone locking assembly are linked, and the locking assembly drives the floating cone locking assembly to move upwards relative to the hanger body; when the pressure is built up in the second stage of the pressure building mechanism, the second pressure building cavity is built up in pressure, and the driving assembly is activated to unlock the hanging slip assembly and realize sitting and hanging of the hanging slip assembly; the fixed slip assembly can be unlocked and fixed sitting and hanging can be realized through the locking assembly, the floating cone locking assembly and the driving assembly which move downwards.

According to one embodiment of the invention, the locking assembly comprises a push sleeve sleeved outside the hanger body and a clamping device positioned between the hanger body and the push sleeve, wherein the clamping device is connected with the push sleeve; the floating cone locking assembly comprises a cone-shaped piece, and the upper end part of the cone-shaped piece is positioned between the push sleeve and the hanger body; when the pressure-holding mechanism does not hold pressure, the clamping device is connected with the upper end of the conical part and locks the conical part on the hanger body, and when the pressure-holding mechanism holds pressure at one stage, the clamping device is disconnected with the upper end of the conical part.

According to one embodiment of the invention, the clamping device is connected to the upper part of the conical part by a first shear pin, which is sheared off when the pressure build-up mechanism builds up pressure in one stage.

According to one embodiment of the invention, the cone is provided with a male block, and the hanger body is provided with a recess matching the male block; when the pressure-building mechanism is not building, the convex block is jointed in the groove to lock the locking assembly and the floating cone locking assembly; when the locking assembly is unlocked, the male block disengages from the recess.

According to one embodiment of the invention, the conical piece is provided with a third pressure transmission hole; when the pressure holding mechanism does not hold pressure, the first pressure transmission hole is in fluid communication with the first pressure holding cavity through the third pressure transmission hole; after the first-stage pressure holding of the pressure holding mechanism causes the floating cone locking assembly to be unlocked and move upwards, the cone member seals a fluid communication path between the first pressure transmission hole and the first pressure holding cavity.

According to one embodiment of the invention, a first sealing member and a second sealing member are arranged between the push sleeve and the conical piece at a longitudinal interval, and the first pressure-holding cavity is formed between the push sleeve and the conical piece through the first sealing member and the second sealing member.

According to one embodiment of the invention, the locking assembly is provided with a first linkage member, the floating cone locking assembly is provided with a second linkage member, and after the locking assembly is unlocked and moves a certain distance relative to the hanger body, the first linkage member abuts against the second linkage member to drive the floating cone locking assembly to move upwards relative to the hanger body through the locking assembly.

According to one embodiment of the invention, the clamping device is connected to the push sleeve by means of a second shear pin.

According to one embodiment of the invention, a sealing assembly is arranged between the lower end of the push sleeve and the conical piece, and the sealing assembly is fixedly connected with the lower end of the push sleeve; the push sleeve is movable downwardly relative to the cone to push the seal assembly to seat between the cone and an upper casing when the second shear pin is sheared.

According to one embodiment of the invention, the gripping means comprise a plurality of flexible gripping arms distributed in the circumferential direction, the ends of the flexible gripping arms and the male block of the cone being connected to the push sleeve by the first shear pin.

According to one embodiment of the invention, the floating cone locking assembly further comprises a clamping member connected with the lower end of the cone, the clamping member comprising a plurality of clamping arms between the hanger body and the drive assembly, the plurality of clamping arms effecting a locking connection of the floating cone locking assembly with the hanger body under the limiting action of the drive assembly.

According to one embodiment of the invention, the drive assembly comprises a spacer assembly, a pull ring coupled to the spacer assembly, a plurality of pull rods coupled to the pull ring, and a piston sleeve; wherein the pull ring is connected to a radially inner surface of a lower end of the spacer assembly, thereby forming a space between the hanger body, the pull ring and the spacer assembly for accommodating movement of the piston sleeve, the lower end of the piston sleeve being fixedly connected to the pull ring and forming the second pressure holding chamber between the piston sleeve, the pull ring and the hanger body; the pull rods extend downwards along the hanger body until being located below a part of the hanging slip assembly, when the second pressure holding cavity holds pressure, the piston sleeve moves upwards to drive the pull ring and the pull rods connected with the pull ring to move upwards, and therefore the hanging slip assembly is unlocked.

According to one embodiment of the present invention, the suspension slip assembly comprises a quill clamp, a suspension slip, and a traveling lock ring, wherein an upper end of the quill clamp is fixedly connected to the suspension slip, the quill clamp being disposed between the suspension slip and the hanger body; the traveling lock ring is positioned between the lower end of the quill clamp and the hanging slips to lock the quill clamp to the hanger body when the hanging slip assembly is locked and is spaced from the lower end of the quill clamp when the hanging slip assembly is unlocked.

According to one embodiment of the invention, the quill clamp is provided with a plurality of flexible collet fingers uniformly distributed along the circumference; the moving locking ring secures the flexible collet within the concave groove of the hanger body when the hanger slip assembly is locked; the flexible collet is released from the concave groove when the suspension slip assembly is unlocked.

According to one embodiment of the invention, upon activation of the drive assembly, the pull rod moves up against the moving lock ring to move the moving lock ring up to release the flexible collet from the concave groove to unlock the hanging slip assembly.

According to one embodiment of the invention, the hanger body is sleeved with the hanging slip assembly and the fixed slip assembly, a first conical surface and a second conical surface are respectively arranged at the positions of the hanging slip assembly and the fixed slip assembly, wherein the contact surface between the first conical surface and the slip arms of the hanging slip assembly is provided with mutually meshed meshing teeth, and the contact surface between the second conical surface and the slip arms of the fixed slip assembly is provided with mutually meshed meshing teeth.

According to one embodiment of the invention, the slip arms of the hanging slip assembly and the slip arms of the fixed slip assembly are provided with engagement teeth engageable with the inner wall of the casing, facing away from the outer surface of the hanger body.

According to one embodiment of the invention, the suspension slip assembly and the stationary slip assembly each include a rail for receiving a slip arm thereof; the slip arms are received in the guide tracks prior to riding; when sitting, the slip arms are disengaged from the guide rails.

According to one embodiment of the present invention, the rails of the hanging slip assembly and the fixed slip assembly are longitudinally aligned one to the other with an axial slot formed between adjacent rails for receiving a portion of an extension of a drive assembly.

According to a second aspect of the present invention there is provided a method of operating a liner hanger with an enhanced locking device as described above comprising the steps of: the hanging slip assembly, the fixed slip assembly, the driving assembly, the floating cone locking assembly and the locking assembly are sleeved on the outer wall of the hanger body in sequence, and the sending tool is connected and locked with the hanger body; connecting a liner or liner string to the hanger body and feeding the connected liner hanger or liner string into the well; performing a liner hanger set, comprising: the connection between the floating cone locking assembly and the locking assembly is disconnected through primary pressure holding, the locking assembly is unlocked, the locking assembly moves upwards relative to the hanger body, and after the locking assembly moves upwards for a certain distance, the linkage between the floating cone locking assembly and the locking assembly is realized; activating the driving assembly through secondary hold-down pressure to unlock the hanging slip assembly and realize sitting and hanging of the hanging slip assembly; lowering a liner hanger, applying a downward appropriate weight to the locking assembly, and sequentially transmitting downward to the floating cone locking assembly, the drive assembly and the fixed slip assembly thereby effecting setting of the fixed slip assembly; and after the construction operation is finished, the connection between the feeding tool and the hanger body is released, and the feeding tool is lifted.

By adopting the technical scheme, the invention has at least the following beneficial effects:

according to the liner hanger with the enhanced locking device, the locking assembly is arranged, so that all components can be prevented from being started before the liner hanger is unlocked; by arranging the multistage locking, other components of the liner hanger can be effectively prevented from being started prematurely, and the liner hanger can be effectively prevented from being sat and hung in advance; smooth driving sitting and hanging is realized through the cooperation of the locking assembly, the floating cone locking assembly, the driving assembly, the fixed slip assembly and the hanging slip assembly.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings that are needed for 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 other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

FIG. 1 is a schematic view of a liner hanger with an enhanced locking device according to one embodiment of the present invention;

FIG. 2 is a schematic view of a liner hanger with an enhanced locking device according to another embodiment of the present invention;

FIG. 3 is an enlarged view of a portion of the dashed box of FIG. 2;

FIG. 4 is a schematic view of a portion of a liner hanger locking assembly with an enhanced locking arrangement in accordance with an embodiment of the present invention;

FIG. 5 is a schematic partial cross-sectional view of a portion of a liner hanger locking assembly with an enhanced locking arrangement in one state provided in an embodiment of the present invention;

FIG. 6 is a schematic partial cross-sectional view of a portion of a liner hanger locking assembly with an enhanced locking arrangement in accordance with an embodiment of the present invention in another state;

FIG. 7 is a schematic partial cross-sectional view of a portion of a liner hanger locking assembly with an enhanced locking arrangement in accordance with an embodiment of the present invention in another state;

FIG. 8 is a schematic partial cross-sectional view of a portion of a liner hanger locking assembly with an enhanced locking arrangement in accordance with an embodiment of the present invention in another state;

FIG. 9 is a schematic partial external view of a floating cone locking assembly gripping member portion of a liner hanger with enhanced locking apparatus provided in an embodiment of the present invention;

FIG. 10 is a schematic partial cross-sectional view of a portion of a floating cone locking assembly of a liner hanger with an enhanced locking device provided in an embodiment of the present invention;

FIG. 11 is a schematic partial external view of a pull ring portion of a drive assembly of a liner hanger with an enhanced locking device provided in an embodiment of the present invention;

FIG. 12 is a schematic partial cross-sectional view of a portion of a drive assembly of a liner hanger with an enhanced locking device provided in an embodiment of the present invention;

FIG. 13 is a schematic partial external view of a portion of a hanging slip assembly provided in an embodiment of the present invention with a liner hanger having an enhanced locking device;

FIG. 14 is another partial external view of a portion of a hanging slip assembly provided in an embodiment of the present invention with a liner hanger having an enhanced locking device;

FIG. 15 is a schematic partial cross-sectional view of a slip lock portion of a hanging slip assembly with a liner hanger having an enhanced locking device provided in an embodiment of the present invention in one state;

FIG. 16 is a schematic partial cross-sectional view of a slip lock portion of a hanging slip assembly with a liner hanger having an enhanced locking device provided in an embodiment of the present invention in another state;

FIG. 17 is a schematic partial cross-sectional view of a slip lock portion of a hanging slip assembly with a liner hanger having an enhanced locking device provided in an embodiment of the present invention in another state;

FIG. 18 is a schematic partial external view of a portion of a stationary slip assembly having a liner hanger with an enhanced locking device provided in an embodiment of the present invention;

FIG. 19 is another partial external view of a portion of a fixed slip assembly with a liner hanger having an enhanced locking device provided in an embodiment of the present invention.

List of reference numerals

1: a hanger body; 101: an upper end portion; 102: a lower end portion; 103: a groove; 104: a first pressure transmitting hole; 105: a concave groove; 106: a first conical surface; 107: a second conical surface; 108: second pressure transmission hole

2: a locking assembly; 201: a first shear pin; 202: a first sealing member; 203: pushing the sleeve; 204: a clamping device; 205: a second shear pin; 206: a flexible clamping arm; 207: first linkage member

3: a floating cone locking assembly; 301: a male block; 302: a third pressure transmitting hole; 303: a second sealing member (second linkage); 304: a cone; 305: a clamping member; 306: a clamping arm; 307: concave groove

4: a drive assembly; 401: a spacer assembly; 402: a pull ring; 403: a pull rod; 404: a piston sleeve; 406: a circulation loop hole; 407: connecting piece

5: fixing a slip assembly; 501: fixing slips; 502: a slip arm; 503: guide rail

6: hanging a slip assembly; 601: a sleeve clamp; 602: hanging slips; 603: moving the lock ring; 604: a flexible collet; 605: a slip arm; 606: guide rail

7: a seal assembly; 701: a connecting piece; 702: sealing element

A: a first pressure holding cavity; b: second pressure-holding cavity

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the following embodiments of the present invention will be described in further detail with reference to the accompanying drawings.

First, it should be noted that the following detailed description of the specific structure, characteristics, advantages, and the like of the present invention will be given by way of example, however, all descriptions are merely illustrative, and should not be construed as limiting the present invention in any way. Furthermore, any single feature described or implied in the embodiments mentioned herein, or any single feature shown or implied in the figures, may nevertheless be continued in any combination or pruning between these features (or equivalents thereof) to obtain still further embodiments of the invention that may not be directly mentioned herein. In addition, for the sake of simplicity of the drawing, identical or similar features may be indicated at one point in the same drawing.

In the description of the present invention, it should be noted that, directions or positional relationships indicated by terms such as "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., are directions or positional relationships based on those shown in the drawings, or are directions or positional relationships conventionally put in use of the inventive product, are merely for convenience of describing the present invention and simplifying the description, and are not indicative or implying that the apparatus or element to be referred to must have a specific direction, be constructed and operated in a specific direction, and thus should not be construed as limiting the present invention. It should be noted that, in the case of no conflict, the embodiments and features in the embodiments may be combined with each other.

Embodiments of the present invention are described in detail below with reference to fig. 1-19.

Fig. 1 and 2 show an embodiment of a liner hanger with an enhanced locking device provided by the present invention, respectively, wherein fig. 1 is an external view and fig. 2 is a semi-external and semi-sectional view. As shown, the liner hanger includes: a hanger body 1; the locking assembly 2, the floating cone locking assembly 3, the driving assembly 4, the fixed slip assembly 5 and the hanging slip assembly 6 are sleeved outside the hanger body 1 in sequence from top to bottom; and a hold-down mechanism (not shown) provided inside the hanger body 1. Wherein, the hanger body 1 is provided with a first pressure transmitting hole 104 (see fig. 2 and 3) and a second pressure transmitting hole 108 (see fig. 2 and 12). A portion of the floating cone locking assembly 3 is located between the locking assembly 2 and the hanger body 1, and a first pressure build chamber a in fluid communication with the first pressure transfer orifice 104 is formed between the portion of the floating cone locking assembly 3 and the locking assembly 2. A second pressure holding chamber B is formed between the drive assembly 4 and the hanger body 1 in fluid communication with the second pressure transfer orifice 108. When the pressure-building mechanism is not building, the locking assembly 2, the floating cone locking assembly 3, the driving assembly 4, the fixed slip assembly 5 and the hanging slip assembly 6 are locked on the hanger body 1, wherein the locking assembly 2 is connected with the floating cone locking assembly 3; when the first-stage pressure building mechanism builds pressure, the first pressure building cavity A builds pressure, the locking assembly 2 is disconnected with the floating cone locking assembly 3, the locking assembly 2 is unlocked, the locking assembly 2 moves upwards relative to the hanger body 1, after the locking assembly 2 moves upwards for a certain distance, the locking assembly 2 and the floating cone locking assembly 3 are linked, and the locking assembly 2 drives the floating cone locking assembly 3 to move upwards relative to the hanger body 1; when the pressure is built up in the second stage of the pressure building mechanism, the second pressure building cavity B is built up, and the driving component 4 is activated to unlock the hanging slip assembly 5 and realize sitting and hanging of the hanging slip assembly 6; the fixed slip assembly 5 can be unlocked and fixed to sit and hang through the locking assembly 2, the floating cone locking assembly 3 and the driving component 4. In the present invention, the locking assembly 2 acts as the primary lock for the entire liner hanger, and when the locking assembly 2 is locked, all other liner hanger components are not activated, and when the locking assembly 2 is unlocked, all other liner hanger components are activated.

The hanger body 1 is a tubular member, the construction of which is well known in the art and will not be described here too much. The hanger body is a multi-piece structure (as shown in fig. 2) connected to each other, as the invention is not limited in this regard. As shown in fig. 1, the hanger body 1 includes an upper end 101 and a lower end 102. The upper end 101 may be adapted to be releasably connected with a running tool (not shown) and the lower end 102 may be adapted to be connected with a liner or liner string. Before the underground construction operation, a feeding tool is connected with the hanger body 1 to feed the hanger body 1 and each part sleeved on the hanger body into a well; after the underground construction operation is finished, the running tool is separated from the hanger body 1, the hanger body 1 and various parts sleeved on the hanger body are left in the well and hung on the inner wall of the casing, and the running tool is lifted out of the wellhead. In the solution of the invention, the running tool and its connection to the hanger body 1 are in a manner conventional in the art, to which the invention is not limited.

The pressure holding mechanism is well known in the art and is not shown in the drawings of the present invention. The following only describes the specific structure of the pressure holding mechanism in a simple way: the pressure holding mechanism comprises a central tube which is relatively fixedly arranged in the hanger body 1. The central tube can be fixed relative to the hanger body 1 by a running tool. The hold-down mechanism further comprises a sealing member, preferably a rubber plug, fixedly arranged on the outer wall of the central tube for sealing an annular space formed between the central tube and the hanger body 1. In order to realize the inside pressure holding of center tube, pressure holding mechanism still includes the fixed mount pad that sets up on the inner wall of center tube and can be by the sealed pressure holding part who receives of mount pad. The pressure-holding component is preferably a pressure-holding ball. When throwing the pressure holding component towards the interior of the running tool, the pressure holding component falls onto a receiving seat positioned in the central tube, so that the interior of the central tube starts to hold pressure. The term "first-stage pressure holding" refers to that the internal pressure of the central tube reaches a first threshold value; the term "second-stage pressure holding" as used herein means that the internal pressure of the central tube reaches a second threshold value that is greater than the first threshold value. It should be appreciated that the first threshold is a pressure sufficient to break the connection between the locking assembly and the floating cone locking assembly, while the second threshold is a pressure sufficient to activate the drive assembly.

In the context of the present invention, unless otherwise specified, "locking" of a component means that the component is locked relative to the hanger body and cannot move relative to the hanger body; similarly, unless otherwise specified, "unlocking" of a component means that the component is unlocked relative to the hanger body, allowing movement relative to the hanger body.

When the pressure-building mechanism is not building, the locking assembly 2 is connected with the floating cone locking assembly 3 through the first shear pin 201, and the locking assembly 2 is in a locking state at the moment; when the first shear pin 201 is sheared due to the pressure of the pressure-holding mechanism, the locking assembly 2 is disconnected from the floating cone locking assembly 3, and the locking assembly 2 is in an unlocking state. The floating cone locking assembly 3 is provided with a male block 301 and the hanger body 1 is provided with a recess 103 matching the male block 301, the male block 301 engaging in the recess 301 to lock the locking assembly 2 and the floating cone locking assembly 3 when the locking assembly 2 is in the locked state, the male block 301 being disengageable 3 from the recess 103 when the locking assembly 2 is unlocked.

In order to unlock the locking assembly 2 (i.e. shear the first shear pin 201 when the pressure build-up mechanism builds up pressure), a third pressure transfer hole 302 is provided in the radial direction on the floating cone locking assembly 3, as shown in the enlarged partial view of fig. 3, and in the non-build-up state the first pressure transfer hole 104 is aligned with the third pressure transfer hole 302 and with the first build-up chamber a, thereby allowing fluid communication between the first pressure transfer hole 104, the third pressure transfer hole 302 and the first build-up chamber a. When the pressure is first-stage, the fluid in the hanger body 1 can enter the first pressure holding cavity a through the first pressure transmitting hole 104 on the hanger body 1 and the third pressure transmitting hole 302 on the floating cone locking assembly 3 in sequence, so as to apply pressure to the locking assembly 2, push the locking assembly 2 to move upwards and shear the first shear pin 201. Specifically, a first sealing member 202 and a second sealing member 303 are longitudinally arranged between the locking assembly 2 and the floating cone locking assembly 3 at intervals, and a sealed first pressure-blocking cavity A is formed between the floating cone locking assembly 3 and the locking assembly 2 through the first sealing member 202 and the second sealing member 303. After the first-stage pressure-holding mechanism causes the floating cone locking assembly 3 to unlock and move upwards, the third pressure transmitting hole 302 moves upwards accordingly, and is no longer aligned with the first pressure transmitting hole 104 and the first pressure holding cavity a, and the first pressure transmitting hole 104 and the first pressure holding cavity a cannot be in fluid communication.

In order to achieve the interlocking of the locking assembly 2 and the floating cone locking assembly 3 after a certain distance of upward movement of the locking assembly 2, a first interlocking member 207 (for example, in the form of a pin) is provided on the locking assembly 2, and a second interlocking member is provided on the floating cone locking assembly 3, after the locking assembly 2 is unlocked and moved a certain distance relative to the hanger body 1, the first interlocking member 207 contacts against the second interlocking member, thereby driving the floating cone locking assembly 3 to move upward relative to the hanger body 1. In the embodiment shown in the drawings of the present application, the second linkage member is integrated with the second sealing member, i.e. the second linkage member is also the second sealing member at the same time, which contributes to a reduced number of parts and reduced complexity of the construction. Of course, the second linkage member may also be a separate component from the second sealing member.

Fig. 4-8 show a specific structure of the locking assembly 2, wherein fig. 4 is an external view of the locking assembly 2, fig. 5-8 are sectional views of the locking assembly 2 in different states, wherein fig. 5 corresponds to a state in which the pressure holding mechanism is not held, fig. 6 corresponds to a state in which the pressure holding mechanism is pressed at one stage so that the locking assembly 2 is unlocked, fig. 7 corresponds to a state in which the pressure holding mechanism is pressed at one stage continuously so that the floating cone locking assembly 3 is unlocked, and fig. 8 corresponds to a state in which the fixed slip assembly 5 is provided. As shown in fig. 5, the locking assembly 2 includes a push sleeve 203 that is sleeved outside the hanger body 1, and a clamping device 204 that is located between the hanger body 1 and the push sleeve 203. The clamping device 204 is fixed to the push sleeve 203 by a second shear pin 205. In the view of fig. 4, the push sleeve 203 is omitted, whereby the structure of the clamping device 204 is clearly shown, from which it can be seen that the clamping device 204 comprises a plurality of flexible clamping arms 206 distributed in the circumferential direction. When the pressure is not being held, i.e. the locking assembly 2 is in a locked state, as shown in fig. 5, the lower end of the flexible clamping arm 205 and the male block 301 of the floating cone locking assembly 3 are fixed to the push sleeve 203 by the first shear pin 201. When the first stage of the pressure-holding mechanism holds the pressure so that the locking assembly 2 is unlocked, as shown in fig. 6, the first shear pin 201 is sheared, thereby disconnecting the push sleeve 203 and the clamping device 204 from the male block 301 of the floating cone locking assembly 3, and the push sleeve 203 and the clamping device 204 move upwards under the action of pressure. After the pressure holding mechanism continues to hold pressure at one level so that the locking assembly 2 moves up a certain distance, as shown in fig. 7, the floating cone locking assembly 3 is unlocked, the convex block 301 is separated from the groove 103, and the push sleeve 203 and the clamping device 204 drive the floating cone locking assembly 3 to move up relative to the hanger body 1 under the action of pressure. When the fixed slip assembly is arranged, as shown in fig. 8, the push sleeve 203 and the clamping device 204 are pressed down, so that the lower end part of the flexible clamping arm 206 of the clamping device 204 is abutted against the floating cone locking assembly 3, and the floating cone locking assembly 3 is pushed to move downwards, thereby realizing sitting and hanging of the fixed slip assembly.

Fig. 9 to 10 show a specific structure of the floating cone locking assembly 3, wherein fig. 9 is a partial external view of the floating cone locking assembly 3, and fig. 10 is a sectional view of the floating cone locking assembly 3. As shown, floating cone locking assembly 3 includes cone 304. The upper end of the cone 304 is tapered with an outer diameter gradually increasing from top to bottom. The tapered upper end of the tapered member 304 extends into the space between the locking assembly 2 and the hanger body 1. A third pressure transfer hole 302 is provided at the upper end of the cone 304. When the pressure build-up mechanism is not build-up, the clamping device 204 is connected to the conical upper end of the conical member 304 via the first shear pin 201 and locks the conical member 304 to the hanger body 1. When the pressure is built up at one stage, the first shear pin 201 is sheared, and the clamping device 204 is disconnected from the upper end of the cone 304. When the pressure holding mechanism continues to hold pressure at one stage, the first linkage member 207 on the push sleeve 203 abuts against the second linkage member on the conical member 304, and the push sleeve 203 drives the conical member 304 to move upwards, so that the third pressure transmitting hole 302 on the conical member 304 deviates from the first pressure transmitting hole 104 and the first pressure holding cavity a, and a fluid communication path between the first pressure transmitting hole 104 and the first pressure holding cavity a is closed, and the first pressure transmitting hole 104 and the first pressure holding cavity a can not be in fluid communication. The male block 301 is provided at the upper end of the cone 304. The floating cone locking assembly 3 further includes a clamping member 305 threadedly connected to the lower end portion of the cone 304. The clamping member 305 comprises a plurality of clamping arms 306 located between the drive assembly 4 and the hanger body 1. In fig. 9, a schematic view of the outer shape of the holding member 305 is shown, from which it can be seen that the plurality of holding arms 306 are uniformly distributed in the circumferential direction. When the floating cone locking assembly 3 is in a locked state, the hanger body 1 is clamped by the clamping arms 306, and the floating cone locking assembly 3 is kept locked and fixed at the initial state position of the hanger body 1 under the limiting action of the driving assembly (particularly a spacing assembly 401 mentioned below). When the clamping arm 306 moves down into the concave slot 307, the clamping arm 306 lacks the radial restraining force of the spacer assembly 401, and unlocking of the cone 304 is achieved. In fig. 10, it can be seen that the clamping arm 306 is tightly connected with the hanger body 1 under the compression of the external spacer assembly 401, when the locking assembly is in the state shown in fig. 8, the floating cone locking assembly 3 moves down, the cone 304 moves down, the clamping member 305 is pushed to move down, the clamping arm 306 enters into the concave groove 307, unlocking of the floating cone locking assembly (here unlocking of the downward movement) is achieved, and the clamping arm 306 can freely move axially in the concave groove 307. Furthermore, it should be mentioned that the lower end of the clamping arm 306 comprises a radially enlarged projection, the clamping arm 306 having no locking effect on the cone 304 when the projection of the clamping arm 306 is located in the concave groove 307, and the clamping arm 306 having a locking effect on the cone 304 when the projection of the clamping arm 306 is not located in the concave groove 307.

The drive assembly 4 abuts the floating cone locking assembly 3, thereby unlocking the drive assembly 4 when the floating cone locking assembly 3 is moved downward relative to the hanger body 1. Fig. 11 and 12 show an external view and a sectional view, respectively, of a portion of the drive assembly 4. As shown, the drive assembly 4 includes a spacer assembly 401 that abuts the floating cone locking assembly 3 (specifically, the clamping member 305), a pull ring 402 connected to the spacer assembly 401, a plurality of pull rods 403 connected to the pull ring 402, and a piston sleeve 404 connected to the pull ring 402. Wherein the pull ring 402 is connected to the radially inner surface of the spacer assembly 401 by a connecting member 407 (e.g. a pin), thereby forming a space between the hanger body 1, the pull ring 402 and the spacer assembly 401 for accommodating movement of the piston sleeve 404, in which space the piston sleeve 404 can move up and down. The piston sleeve 404 and the hanger body 1 and the pull ring 402 form a second pressure-holding cavity B under the action of a sealing element. The piston sleeve 404 is threadably connected to the pull ring 402. In the embodiment shown in fig. 12, the upper ends of a plurality of tie rods 403 are connected to the tab 402. A plurality of tie rods 403 extend down the hanger body 1 until below a portion of the hanging slip assembly 6. As shown in fig. 11, the pull ring 402 is a ring-shaped member, and a plurality of pull rods 403 are uniformly connected to the circumference of the pull ring 402. The upper annular sleeve of the spacer assembly 401 contacts the step of the gripping member 305 and the lower end thereof contacts the stationary slip assembly (specifically, the circular sleeve of the stationary slip 501, described below). After the first pressure transmission hole 104 is blocked due to the first pressure-holding, the second pressure holding is continued, the pressure enters the second pressure holding cavity B from the second pressure transmission hole 108, the piston sleeve 404 is pushed to move upwards, the pull ring 402 is driven to move upwards, the pull rod 403 is moved upwards, and finally the hanging slip 6 is hung. The interval assembly 401 is provided with a circulation hole 406 for reducing the pressure difference during the upward movement of the second pressure-holding chamber B holding piston sleeve 404.

Fig. 13-17 illustrate a specific construction of the suspension slip assembly 6, wherein fig. 13 and 14 are exterior views of the suspension slip assembly 6, and fig. 15-17 are cross-sectional views of the suspension slip assembly 6 in different states, wherein fig. 15 corresponds to a locked state of the suspension slip assembly 6, fig. 16 corresponds to an unlocked state of the suspension slip assembly 6, and fig. 17 corresponds to a set-up state of the suspension slip assembly 6. As shown, the suspension slip assembly 6 includes a quill clamp 601, a suspension slip 602, and a shift lock ring 603, wherein the quill clamp 601 and the suspension slip 602 are fixedly connected (e.g., threaded), and the quill clamp 601 is disposed between the suspension slip 602 and the hanger body 1. When the suspension slip assembly 6 is in the locked condition, as shown in figure 15, a shift lock ring 603 is located between the lower end of the quill clip 601 and the suspension slips 601 to lock the quill clip 601 to the hanger body 1. Specifically, the collet 601 has a plurality of circumferentially equispaced flexible collet jaws 604, the flexible collet 604 being bent radially outwardly by the collet 601, the collet 601 being constrained in a radial direction by an annular moving lock ring 603 radially fitted over the flexible collet 604, locking into a concave groove 105 in the hanger body 1. In this state, the pull rod 403 is longitudinally spaced apart from the shift lock ring 603. When the drive assembly is activated, the pull rod 403 moves up against the shift lock ring 603 to move the shift lock ring 603 up, releasing the flexible collet 604 from the concave groove 105, unlocking the hanging slip assembly 6, the unlocked state of the hanging slip assembly 6 being shown in FIG. 16. The provision of the shift lock ring 603 prevents premature shifting of the hanging slips 602 to seat in advance. After the hanging slip assembly 6 is unlocked, after the moving lock ring 603 moves up to abut against the upper part of the collet chuck 601, the continued upward movement of the pull ring 403 will drive the moving lock ring 603, the sleeve clamp 601 abutting against it and the hanging slip 602 abutting against the sleeve clamp 601 to move up together, the hanging slip 602 moves up and out along the conical surface on the hanger body 1, thereby achieving a seated hanging in the sleeve, the seated hanging state of the hanging slip assembly 6 is shown in fig. 17. As shown in fig. 13, a plurality of slip arms 605 are uniformly provided at the upper end of the hanging slip 602 in the circumferential direction, and the plurality of slip arms 605 are seated on the inner wall of the casing during the seating process.

In some cases, the hanger body 1 is provided with a first conical surface 106 (visible in fig. 1 and 14) near the location where the hanger body is nested with the hanging slip assembly 6, wherein the contact surface between the first conical surface 106 and the slip arms 605 of the hanging slip 602 of the hanging slip assembly 6 is provided with inter-engaging teeth for limiting axial movement (e.g., downward movement) of the hanging slip assembly 6 after the hanger is seated, ensuring a seating effect. The outer surfaces of the slip arms 605 of the hanging slips 602 of the hanging slip assembly 6 facing away from the hanger body 1 are provided with engagement teeth (visible in fig. 13) engageable with the inner wall of the casing for limiting axial movement (e.g. downward movement) of the hanging slip assembly 6 relative to the inner wall of the casing after the hanger is set, ensuring a setting effect.

As shown in fig. 13 and 14, the suspension slip assembly 6 also includes rails 606 for preventing the slip arms 605 of the suspension slips 602 from wedging radially outward during running of the liner hanger. Each slip arm 605 is provided with a corresponding rail 606. The guide track 603 comprises a first side and a second side, which are symmetrically arranged, provided with opposite openings. Before setting, the two sides of the slip arms 605 of the hanging slip 602 are received in the first and second sides of the rail 606, respectively, limiting the movement of the slip arms 605 radially outward. During setting, the two sides of the slip arms 605 of the hanging slips 602 are disengaged from the rails 606 for setting. The guide rail 606 may be connected to the hanger body 1 or may be part of an integral design with the hanger body. An axial slot formed between adjacent guide rails 606 on the liner hanger body 1 allows the pull rod 403 to pass therethrough. By providing the rails 606, the hanging slips 602 do not move radially outward during running due to tool movement or slip arms being squeezed by accumulated debris, and premature setting can be effectively avoided.

Fig. 18-19 illustrate a specific construction of the stationary slip assembly 5. The stationary slip assembly 5 includes a stationary slip 501, an upper end of the stationary slip 501 abutting a spacer assembly 401 (see fig. 12) of the drive assembly 4, and a lower end of the stationary slip 501 being uniformly provided with a plurality of slip arms 502 in a circumferential direction. The plurality of slip arms 502 ride on the inner wall of the casing during the ride. In some cases, a second conical surface 107 (visible in fig. 1 and 19) is provided adjacent to the location where the hanger body 1 is nested with the fixed slip assembly 5, wherein the contact surface between the second conical surface 107 and the slip arms 502 of the fixed slip 501 of the fixed slip assembly 5 is provided with inter-engaging teeth for limiting axial movement (e.g., upward movement) of the fixed slip assembly 5 after the hanger is seated, ensuring a seating effect. The slip arms 502 of the fixed slips 501 of the fixed slip assembly 5 are provided with engagement teeth (visible in fig. 18 and 19) facing away from the outer surface of the hanger body 1 which engage the inner wall of the casing for limiting axial movement (e.g. upward movement) of the fixed slip assembly 5 relative to the inner wall of the casing after the hanger is set, ensuring a setting effect.

As shown in fig. 18 and 19, the fixed slip assembly 5 further includes rails 503 for preventing the slip arms 502 of the fixed slips 501 from wedging radially outward during running of the liner hanger. The structure of the rail 503 is similar to the structure of the rail 606 mentioned above, and the rail 503 includes a first side portion and a second side portion, which are symmetrically disposed and are provided with opposite openings. The two sides of the slip arms 502 of the fixed slip 501 are received in the first and second sides of the rail 503, respectively, prior to setting, limiting the movement of the slip arms 503 radially outward. During setting, the two sides of the slip arms 502 of the fixed slips 501 are disengaged from the rails 503 for setting. The guide rail 503 may be attached to the hanger body 1 or may be a part of an integrated design with the hanger body. An axial slot formed in the liner hanger body 1 between adjacent guide rails 503 allows the pull rod 403 to pass therethrough. To facilitate passage of the tie rod 403 through both the fixed slip assembly 5 and the hanging slip assembly 6 to unlock the hanging slip assembly 6, the rail 503 is aligned with the rail 606 in the longitudinal direction. By providing the guide rails 503, the fixed slips 501 do not move radially outwards during the running process due to tool movement or extrusion of the slip arms by accumulated scraps, and early sitting and hanging can be effectively avoided.

As shown in fig. 1, 2 and 10, a sealing assembly 7 is provided between the lower end of the push sleeve 203 and the cone 304. As shown in fig. 10, the seal assembly 7 includes a connector 701 and a seal 702 provided on the connector 701, wherein the connector 701 is sleeved on an outer surface of the cone 304 and fixedly connected (e.g., screwed) with a lower end of the push sleeve 203. After the setting is completed, when a greater weight is placed on the liner hanger by the running tool, the downward force on the push sleeve 203 will shear the second shear pin 205 connecting between the push sleeve 203 and the gripping device 204, thereby allowing the push sleeve 203 to move downward relative to the cone 304, as the seal assembly 7 is fixedly connected to the push sleeve 203, the push sleeve 203 moves the seal assembly 7 downward along the conical surface of the cone 304 until the seal assembly 7 sealingly engages the upper casing inner wall. It will be appreciated that the above-described arrangement of the seal assembly 7 is not required and may be selectively arranged as required. For example, it may be determined from downhole conditions whether this functionality needs to be added. The function of the sealing component 7 is equivalent to that of a packer of the existing packing type hanger, the operation of the sealing component 7 can be realized only by applying a certain weight, and compared with the existing packing type hanger, the packing type hanger needs to adjust the pressure to realize simpler operation.

The working principle and the operation process of the embodiment of the liner hanger with the enhanced locking device provided by the embodiment of the invention are as follows:

first, the liner hanger is assembled. Specifically, the hanging slip assembly 6, the fixed slip assembly 5, the driving assembly 4, the floating cone locking assembly 3 and the locking assembly 2 are sleeved on the outer wall of the hanger body 1 in sequence; the running tool is connected and locked with the upper end 101 of the hanger body 1.

Thereafter, the liner hanger is fed. Specifically, a liner or liner string is connected to the lower end portion of the hanger body 1, and a running tool (e.g., a running drill pipe) is connected to the running tool to run the liner.

Thereafter, the liner hanger is set. Comprising the following steps: the connection between the floating cone locking assembly 3 and the locking assembly 2 is disconnected through primary pressure build-up, the locking assembly 2 is unlocked, the locking assembly 2 moves upwards relative to the hanger body 1, and after the locking assembly 2 moves upwards for a certain distance, the upward linkage between the floating cone locking assembly 3 and the locking assembly 2 is realized; activating the driving assembly 4 through secondary pressure holding to unlock the suspension slip assembly 6 and realize sitting and hanging of the suspension slip assembly 6; the tail pipe hanger is lowered, proper downward weight is applied to the locking assembly 2, and the weight is sequentially transferred to the floating cone locking assembly 3 and the driving assembly 4 until the slip assembly is fixed, so that the slip assembly is fixed and hung. Specifically, after the liner hanger is lowered into the casing to a designed depth, a ball is thrown, from the first stage of pressure build-up of the lowering tool, fluid enters the first pressure build-up cavity A through the first pressure transmission hole 104, the first shear pin 201 is sheared, the push sleeve 203 moves upwards relative to the hanger body 1, after the push sleeve 203 moves upwards for a certain distance, the first linkage member 207 on the push sleeve 203 abuts against the second linkage member 303 on the conical member 304, the push sleeve 203 drives the conical member 304 to move upwards, and the conical member 304 moves upwards to seal the first pressure transmission hole 104; then, the second-stage pressure is built in, fluid enters a second pressure build-up cavity B through a second pressure transmission hole 108, a piston sleeve 404 moves upwards under the action of pressure, a pull rod 403 pulls a moving lock ring 603 upwards to unlock a hanging slip assembly 6, after the moving lock ring 603 abuts against a sleeve collet 601, the pull rod 403 continues to pull upwards to drive a hanging slip 602 to move upwards, and sitting and hanging of the hanging slip 602 are achieved; lowering the setting tool, applying a certain weight, the additional weight applied to the liner hanger pushing down the push sleeve 203 (this can be achieved by the setting tool), the weighted weight being transferred to the cone 304 by the push sleeve 203, pushing the spacer assembly 401 down, and thus pushing the fixed slip assembly 5 down to open in the conical direction, effecting setting of the fixed slip assembly 5, in the process, the gripping arms 306 of the gripping members 305 move down into the concave grooves 307, effecting axial freedom of the cone 304 relative to the hanger body 1; when the additional weight is pressed further down, the push sleeve 203 shears the second shear pin 205, and the final seal assembly 7 seals the annular space with the upper casing by the cone 304. So far, the liner hanger has been fully set. In the above process, after the hanging slips are set, the hanging slips 602 may be lowered into the tool to carry the full weight of the liner hanger and its lower liner and liner string to verify that the liner hanger is set in place in the wellbore.

Then, back-off of the liner hanger, well cementation construction and the like can be carried out according to the conventional method.

After the application operation is finished, the connection between the running tool and the hanger body 1 is released, the running tool is put forward, and after the running tool is put forward, a complete integral structure without any hidden danger of pressure leakage is left in the well, so that the integrity of the well bore is ensured.

If the attempt to press down on the tool fails, the liner hanger may be set downhole, forcing the gripping device 204 and the push sleeve 203 downward by the press until the gripping device 204 passes the male block 301, unlocking the locking assembly 2. The travel distance required to unlock the locking assembly 2 by the downward movement of the push sleeve 203 is greater so that the locking assembly 2 is not accidentally unlocked when the running tool performs an emergency disconnection operation.

The foregoing is an exemplary embodiment of the present disclosure, and the order in which the embodiments of the present disclosure are disclosed is merely for the purpose of description and does not represent the advantages or disadvantages of the embodiments. It should be noted that the above discussion of any of the embodiments is merely exemplary and is not intended to suggest that the scope of the disclosure of embodiments of the invention (including the claims) is limited to these examples and that various changes and modifications may be made without departing from the scope of the invention as defined in the claims. The functions, steps and/or actions of the method claims in accordance with the disclosed embodiments described herein need not be performed in any particular order. Furthermore, although elements of the disclosed embodiments may be described or claimed in the singular, the plural is contemplated unless limitation to the singular is explicitly stated.

Those of ordinary skill in the art will appreciate that: the above discussion of any embodiment is merely exemplary and is not intended to imply that the scope of the disclosure of embodiments of the invention, including the claims, is limited to such examples; combinations of features of the above embodiments or in different embodiments are also possible within the idea of an embodiment of the invention, and there are many other variations of the different aspects of the embodiments of the invention as described above, which are not provided in detail for the sake of brevity. Therefore, any omissions, modifications, equivalent substitutions, improvements, and the like, which are made within the spirit and principles of the embodiments of the invention, are included within the scope of the embodiments of the invention.

Claims (20)

1. A liner hanger with enhanced locking means, comprising:

the hanger comprises a hanger body, wherein the hanger body is provided with a first pressure transmission hole and a second pressure transmission hole;

the locking assembly, the floating cone locking assembly, the driving assembly, the fixed slip assembly and the hanging slip assembly are sleeved outside the hanger body in sequence from top to bottom, wherein a part of the floating cone locking assembly is positioned between the locking assembly and the hanger body, a first pressure holding cavity in fluid communication with the first pressure transmission hole is formed between the part of the floating cone locking assembly and the locking assembly, and a second pressure holding cavity in fluid communication with the second pressure transmission hole is formed between the driving assembly and the hanger body;

A pressure holding mechanism arranged inside the hanger body,

when the pressure-building mechanism is not building, the locking assembly, the floating cone locking assembly, the driving assembly, the fixed slip assembly and the hanging slip assembly are all locked on the hanger body, wherein the locking assembly is connected with the floating cone locking assembly; when the first pressure-holding cavity holds pressure, the locking assembly is disconnected with the floating cone locking assembly to unlock the locking assembly, the locking assembly moves upwards relative to the hanger body, after the locking assembly moves upwards for a certain distance, the locking assembly and the floating cone locking assembly are linked, and the locking assembly drives the floating cone locking assembly to move upwards relative to the hanger body; when the pressure is built up in the second stage of the pressure building mechanism, the second pressure building cavity is built up in pressure, and the driving assembly is activated to unlock the hanging slip assembly and realize sitting and hanging of the hanging slip assembly; the fixed slip assembly can be unlocked and fixed sitting and hanging can be realized through the locking assembly, the floating cone locking assembly and the driving assembly which move downwards.

2. The liner hanger with enhanced locking device of claim 1, wherein:

the locking assembly comprises a pushing sleeve sleeved outside the hanger body and a clamping device positioned between the hanger body and the pushing sleeve, and the clamping device is connected with the pushing sleeve;

the floating cone locking assembly comprises a cone-shaped piece, and the upper end part of the cone-shaped piece is positioned between the push sleeve and the hanger body;

when the pressure-holding mechanism does not hold pressure, the clamping device is connected with the upper end of the conical part and locks the conical part on the hanger body, and when the pressure-holding mechanism holds pressure at one stage, the clamping device is disconnected with the upper end of the conical part.

3. The liner hanger with enhanced locking device of claim 2, wherein the gripping device is connected to the upper portion of the cone member by a first shear pin that is sheared off at a first level of pressure hold of the pressure hold mechanism.

4. A liner hanger with enhanced locking device according to claim 3, wherein the cone is provided with a male block and the hanger body is provided with a recess matching the male block; when the pressure-building mechanism is not building, the convex block is jointed in the groove to lock the locking assembly and the floating cone locking assembly; when the locking assembly is unlocked, the male block disengages from the recess.

5. The liner hanger with enhanced locking device of claim 2, wherein the cone is provided with a third pressure transmitting aperture; when the pressure holding mechanism does not hold pressure, the first pressure transmission hole is in fluid communication with the first pressure holding cavity through the third pressure transmission hole; after the first-stage pressure holding of the pressure holding mechanism causes the floating cone locking assembly to be unlocked and move upwards, the cone member seals a fluid communication path between the first pressure transmission hole and the first pressure holding cavity.

6. A liner hanger with enhanced locking device according to claim 2, wherein a first sealing member and a second sealing member are provided longitudinally spaced between the push sleeve and the cone, the first pressure build-up chamber being formed between the push sleeve and the cone by the first sealing member and the second sealing member.

7. The liner hanger with enhanced locking apparatus of claim 1, wherein the locking assembly is provided with a first linkage and the floating cone locking assembly is provided with a second linkage, the first linkage abutting the second linkage to drive the floating cone locking assembly upward relative to the hanger body via the locking assembly after the locking assembly is unlocked and moved a distance relative to the hanger body.

8. The liner hanger with enhanced locking device of claim 2, wherein the gripping device is coupled to the push sleeve by a second shear pin.

9. The liner hanger with enhanced locking apparatus of claim 8, wherein a seal assembly is disposed between the lower end of the push sleeve and the cone, the seal assembly being fixedly coupled to the lower end of the push sleeve; the push sleeve is movable downwardly relative to the cone to push the seal assembly to seat between the cone and an upper casing when the second shear pin is sheared.

10. The liner hanger with enhanced locking device of claim 4, wherein the gripping device comprises a plurality of circumferentially distributed flexible gripping arms, the ends of the flexible gripping arms and the male block of the cone being connected to the push sleeve by the first shear pin.

11. The liner hanger with enhanced locking apparatus of claim 2, wherein the floating cone locking assembly further comprises a clamp member connected to a lower end of the cone, the clamp member comprising a plurality of clamp arms between the hanger body and the drive assembly, the plurality of clamp arms effecting a locking connection of the floating cone locking assembly to the hanger body under a limiting action of the drive assembly.

12. The liner hanger with enhanced locking apparatus of claim 1, wherein the drive assembly comprises a spacer assembly, a pull ring coupled to the spacer assembly, a plurality of pull rods coupled to the pull ring, and a piston sleeve;

wherein the pull ring is connected to a radially inner surface of a lower end of the spacer assembly, thereby forming a space between the hanger body, the pull ring and the spacer assembly for accommodating movement of the piston sleeve, the lower end of the piston sleeve being fixedly connected to the pull ring and forming the second pressure holding chamber between the piston sleeve, the pull ring and the hanger body;

the pull rods extend downwards along the hanger body until being located below a part of the hanging slip assembly, when the second pressure holding cavity holds pressure, the piston sleeve moves upwards to drive the pull ring and the pull rods connected with the pull ring to move upwards, and therefore the hanging slip assembly is unlocked.

13. The liner hanger with enhanced locking device of claim 12, wherein the hanging slip assembly comprises a quill clamp, a hanging slip and a traveling lock ring, wherein an upper end of the quill clamp is fixedly connected to the hanging slip, the quill clamp being disposed between the hanging slip and the hanger body;

The traveling lock ring is positioned between the lower end of the quill clamp and the hanging slips to lock the quill clamp to the hanger body when the hanging slip assembly is locked and is spaced from the lower end of the quill clamp when the hanging slip assembly is unlocked.

14. The liner hanger with enhanced locking device of claim 13, wherein the sleeve clamp is provided with a plurality of flexible collets circumferentially equispaced; the moving locking ring secures the flexible collet within the concave groove of the hanger body when the hanger slip assembly is locked; the flexible collet is released from the concave groove when the suspension slip assembly is unlocked.

15. The liner hanger with enhanced locking device of claim 14, wherein upon activation of the drive assembly, the pull rod moves up against the moving lock ring to move the moving lock ring up to release the flexible collet from the concave groove to unlock the hanging slip assembly.

16. The liner hanger with enhanced locking apparatus of claim 1, wherein the hanger body is provided with a first conical surface and a second conical surface, respectively, at the location of the hanging slip assembly and the fixed slip assembly, wherein a contact surface between the first conical surface and the slip arms of the hanging slip assembly is provided with inter-engaging teeth, and a contact surface between the second conical surface and the slip arms of the fixed slip assembly is provided with inter-engaging teeth.

17. The liner hanger with enhanced locking device of claim 1, wherein the slip arms of the hanging slip assembly and the slip arms of the securing slip assembly are provided with engagement teeth engageable with the inner wall of the casing away from the outer surface of the hanger body.

18. The liner hanger with enhanced locking device of claim 1, wherein the hanging slip assembly and the stationary slip assembly each comprise a rail for receiving a slip arm thereof; the slip arms are received in the guide tracks prior to riding; when sitting, the slip arms are disengaged from the guide rails.

19. The liner hanger with enhanced locking apparatus of claim 17, wherein the guide rails of the hanging slip assembly and the fixed slip assembly are longitudinally aligned one to the other with an axial slot formed between adjacent guide rails for receiving a portion of an extension of a drive assembly.

20. A method of operating a liner hanger with enhanced locking apparatus as claimed in any one of claims 1 to 19, comprising the steps of:

the hanging slip assembly, the fixed slip assembly, the driving assembly, the floating cone locking assembly and the locking assembly are sleeved on the outer wall of the hanger body in sequence, and the sending tool is connected and locked with the hanger body;

Connecting a liner or liner string to the hanger body and feeding the connected liner hanger or liner string into the well;

performing a liner hanger set, comprising: the connection between the floating cone locking assembly and the locking assembly is disconnected through primary pressure holding, the locking assembly is unlocked, the locking assembly moves upwards relative to the hanger body, and after the locking assembly moves upwards for a certain distance, the linkage between the floating cone locking assembly and the locking assembly is realized; activating the driving assembly through secondary hold-down pressure to unlock the hanging slip assembly and realize sitting and hanging of the hanging slip assembly; lowering a liner hanger, applying a downward appropriate weight to the locking assembly, and sequentially transmitting downward to the floating cone locking assembly, the drive assembly and the fixed slip assembly thereby effecting setting of the fixed slip assembly;

and after the construction operation is finished, the connection between the feeding tool and the hanger body is released, and the feeding tool is lifted.