CN114575773A - Tail pipe suspension device with top packer and tail pipe suspension assembly - Google Patents

Abstract

The invention relates to a tail pipe suspension device with a top packer and a tail pipe suspension assembly. The tail pipe linkage includes: a suspension body sleeve extending in an axial direction; the slip hanging mechanism is sleeved outside the hanging main body sleeve; the packer assembly is sleeved outside the suspension main body sleeve and connected to the slip suspension mechanism; the tie-back cylinder is sleeved outside the suspension main body sleeve and connected to the packer assembly; wherein the tieback pipe moves downwards at a first pressure to drive the packer assemblies to move downwards together and drive the slip hanging mechanism to sit and hang; wherein downward movement of the tieback at a second pressure greater than the first pressure drives the packer assembly to set.

Description

Tail pipe suspension device with top packer and tail pipe suspension assembly

Technical Field

The invention relates to the technical field of petroleum well completion, in particular to a tail pipe suspension device with a top packer. The invention also relates to a tail pipe suspension assembly comprising the tail pipe suspension device.

Background

The liner hanger is a common downhole tool in current oil exploration and development, and can be divided into three types, namely a mechanical type, a hydraulic type and a hydraulic mechanical double-acting type according to different sitting and hanging modes, wherein the hydraulic liner hanger is most widely applied.

The hydraulic liner hanger is generally a hydraulic cylinder (driving mechanism) which starts the liner hanger by the pressure build-up in the pipe, and the hydraulic cylinder pushes the hanging mechanism to realize sitting and hanging (ZL 201020678270.5). At present, in order to solve the problem of liner cementing under complex well conditions such as a deep well, a small-clearance well, a large-displacement well and the like, various hydraulic liner hangers of different types are developed in China in succession. However, these liner hangers suffer from two problems, basically.

First, the seating and hanging drive mechanism (hydraulic cylinder) of a conventional hydraulic liner hanger is designed outside the suspension body. After the cementing operation is finished, the driving mechanisms are left in the well for a long time. The hydraulic drive mechanism inevitably requires the use of rubber seals. The presence of the rubber seal limits the overall temperature resistance of the tool. In addition, the rubber sealing element is easy to age in a high-temperature and high-pressure environment in the well for a long time, so that the sealing failure of the hydraulic driving mechanism is caused, and the sealing durability of the whole shaft is influenced.

Second, the seat and hang driving mechanism of the conventional hydraulic liner hanger is generally a double-layer mechanism. Due to the small design space, the pressure resistance is generally smaller than that of the same size of casing. This limits the pressure resistance of the entire liner hanger and is not suitable for high temperature and high pressure wells or high pressure fracturing operations.

In addition, there is a significant risk of gas breakthrough in the annulus for high pressure gas wells. Accordingly, it is desirable to install a corresponding top packer on the liner hanger to avoid the occurrence of a gas breakthrough condition. However, with existing liner hangers having a top packer, it is generally necessary to provide a corresponding setting drive mechanism below the slips and an additional packer setting mechanism above the top packer to avoid interference between the setting and setting processes. This is also an important reason why conventional hydraulic liner hangers necessitate the seating drive mechanism be located outside the body of the hanger.

Disclosure of Invention

In view of the above, the present invention proposes a liner hanger that can be used to eliminate or at least reduce at least one of the above problems. The invention further provides a tail pipe suspension assembly.

According to a first aspect of the present invention, there is provided a tail pipe suspension device including: a suspension body sleeve extending in an axial direction; the slip hanging mechanism is sleeved outside the hanging main body sleeve; the packer assembly is sleeved outside the suspension main body sleeve and connected to the slip suspension mechanism; the tie-back cylinder is sleeved outside the suspension main body sleeve and connected to the packer assembly; wherein the tieback pipe moves downwards at a first pressure to drive the packer assemblies to move downwards together and drive the slip hanging mechanism to sit and hang; wherein downward movement of the tieback at a second pressure greater than the first pressure drives the packer assembly to set.

With the above arrangement, it is made possible to effect setting of the slip suspension mechanism and setting of the packer assembly, respectively, by depressing the tieback cylinder with different degrees of force. In this case, it is not necessary to provide a seat hanging drive mechanism on the tail pipe hanging device. The temperature resistance reduction and the leakage problem in the well caused by the rubber sealing element in the sitting and hanging driving mechanism are avoided. Meanwhile, the tail pipe suspension device can avoid the problem of gas channeling and is very suitable for being applied to high-pressure gas wells.

In one embodiment, the slip suspension mechanism comprises: the slip fixing ring is sleeved and arranged outside the sleeve of the suspension main body; the conical sleeve is sleeved outside the suspension main body sleeve, the conical sleeve is arranged on the slip fixing ring and is spaced from the slip fixing ring, a sitting and hanging inclined joint surface is formed at the lower end of the conical sleeve, and the upper end of the conical sleeve is connected with the packer assembly; and a plurality of slips disposed outside the suspension body sleeve, the plurality of slips being circumferentially spaced apart from one another and axially located between the slip retaining ring and the cone sleeve, a lower end of each slip being hinged to the slip retaining ring, an upper end of each slip being configured as a free end; wherein when the tieback is moved downward at a first pressure and drives the packer assembly downward together, the drogue moves downward such that the landing angled interface is interposed between the slips and the suspension body sleeve to cause the upper ends of the slips to move radially outward to effect landing.

In one embodiment, a first anti-back sleeve is connected between the upper end of the drogue and the packer assembly, the first anti-back sleeve being configured to be movable only downward relative to the suspension body sleeve.

In one embodiment, the packer assembly comprises: the expansion sleeve is sleeved outside the suspension main body sleeve, the lower end of the expansion sleeve is connected with the slip suspension mechanism, the upper end of the expansion sleeve is a free end, a packing rubber cylinder is arranged on the outer side of the upper end of the expansion sleeve, and a gap space is formed between the expansion sleeve and the suspension main body sleeve; the expansion cone is sleeved outside the suspension main body sleeve, the upper end of the expansion cone is connected with the tieback sleeve, the lower end of the expansion cone axially extends into a gap space between the expansion sleeve and the suspension main body sleeve, a section of free space is formed in the gap space below the lower end of the expansion cone, the expansion cone is connected with the expansion sleeve through a first shearing pin, and a setting inclined joint face is formed on the outer side face of the expansion cone; when the tieback cylinder moves downwards under the second pressure, the first shearing pin is sheared, so that the expansion cone can move downwards along the axial direction relative to the expansion sleeve, and the setting inclined joint face is inserted between the upper end of the expansion sleeve and the suspension main body sleeve, so that the packing rubber cylinder moves outwards in the radial direction to realize setting.

In one embodiment, a second anti-back-off is provided between the expansion cone and the suspension body sleeve, the second anti-back-off configured to only allow downward movement of the expansion cone relative to the suspension body sleeve.

According to a second aspect of the present invention there is provided a liner hanger assembly comprising a liner hanger as described above, and a running tool configured to engage the liner hanger and to urge the tieback cylinder downwardly at a first pressure and a second pressure.

In one embodiment, the running tool comprises: a mandrel extending in an axial direction; the sitting and hanging driving assembly is sleeved outside the mandrel and comprises a hydraulic mechanism, and the sitting and hanging driving assembly is constructed to push the tieback cylinder downwards under a first pressure; and the setting driving assembly is sleeved outside the mandrel and arranged below the setting hanging driving assembly, and the setting driving assembly is constructed to push the tieback cylinder downwards under a second pressure.

In one embodiment, the sit-on drive assembly comprises the hydraulic mechanism, the hydraulic mechanism comprising: the hydraulic cylinder sleeve is sleeved outside the mandrel and fixedly connected with the mandrel, and a gap is formed between the upper end of the hydraulic cylinder sleeve and the mandrel; and the hydraulic piston is sleeved outside the mandrel, the lower end of the hydraulic piston axially extends into a gap between the hydraulic cylinder sleeve and the mandrel and is in slidable sealing joint with the hydraulic cylinder sleeve and the mandrel, and the hydraulic piston defines an upper hydraulic cavity and a lower hydraulic cavity in the hydraulic cylinder sleeve. The sitting and hanging driving assembly further comprises a sitting and hanging driving sleeve sleeved outside the upper end of the hydraulic piston, and the sitting and hanging driving sleeve is fixedly connected with the hydraulic piston; the lower end of the tieback cylinder joint sleeve abuts against the upper end of the tieback cylinder; wherein when fluid enters the upper hydraulic chamber of the cylinder sleeve, the hydraulic piston is driven to move downwardly such that the landing drive sleeve pushes the tieback cylinder engagement sleeve downwardly and further pushes the tieback cylinder downwardly.

In one embodiment, the running tool further comprises a pressure holding ball seat disposed in the mandrel, wherein the mandrel is configured with a pressure balancing channel having one end connected to the lower hydraulic chamber of the hydraulic cylinder sleeve and the other end connected to the interior of the mandrel below the pressure holding ball seat.

In one embodiment, the hold pressure tee comprises: a plurality of ball seat pieces arranged annularly in a circumferential direction independently of each other, each ball seat piece having an elastic rib engagement groove formed at an inner side of a lower end thereof; and an elastic sleeve having a lower end configured as a complete ring body and an upper end configured as a plurality of elastic ribs extending upward in an axial direction from the ring body, the plurality of elastic ribs being arranged spaced apart from each other in a circumferential direction, an upper end of each elastic rib being insertable into the elastic rib engagement groove of each ball seating flap in a radially inwardly contracted state; during the running process, the ball seat flaps are arranged in the mandrel, the ball seat flaps are folded relative to each other through the inner wall of the mandrel to form a complete ring shape, and the elastic ribs of the elastic sleeve are in a folded state; upon pressure build-up, the plurality of ball seat lobes move downwardly relative to the mandrel to an inner diameter enlargement of the mandrel, and under the resiliency of the respective resilient ribs, the respective ball seat lobes move radially outwardly such that the inner diameter defined by the respective ball seat lobes increases.

In one embodiment, the outer surface of each ball seat flap is formed with a rubber layer.

In one embodiment, the setting driving assembly comprises a setting driving block sleeved outside the mandrel, the upper end of the setting driving block is hinged relative to the mandrel through a driving block connecting piece, and the lower end of the setting driving block is a free end; in the running-in process, the setting driving assembly is located in the tieback cylinder, so that the setting driving block is in a folded state, when the packer assembly needs to be set, the mandrel is lifted up, the setting driving block moves out of the upper end of the tieback cylinder, the lower end of the setting driving block radially expands outwards to be opposite to the upper end face of the tieback cylinder, and the mandrel is pressed downwards so that the tieback cylinder is pressed downwards through the setting driving block.

Drawings

The invention is described in more detail below with reference to the accompanying drawings. Wherein:

FIG. 1 shows a schematic structural view of a liner hanger assembly according to a first embodiment of the invention, including a liner hanger and a running tool;

FIG. 2 shows a schematic view of a portion of the running tool of FIG. 1;

FIGS. 3 and 4 are schematic diagrams illustrating the operation of the pressure build-up tee of the running tool of FIG. 2;

FIG. 5A shows a schematic side cross-sectional view of a ball seat lobe in a build ball seat of the running tool of FIG. 2;

FIG. 5B shows a schematic top cross-sectional view of the ball seat flap of FIG. 5A;

FIG. 5C shows a schematic perspective view of the ball seat flap of FIG. 5A;

FIG. 6 is a schematic diagram of the configuration of the elastomeric sleeve in the hold down ball seat of the running tool of FIG. 2;

FIG. 7 shows a schematic view of the tailpipe suspension of FIG. 1;

fig. 8 shows an enlarged view of a portion of the tailpipe suspension of fig. 7.

In the drawings, like parts are provided with like reference numerals. The figures are not drawn to scale.

Detailed Description

The invention will be further explained with reference to the drawings.

In this context, unless explicitly stated otherwise or unless contradicted, the term "up" means the side near the wellhead when the equipment is lowered into the well, and the term "down" means the side near the bottom of the well when the equipment is lowered into the well.

As used herein, the terms "connected," "coupled," and the like are intended to encompass both a direct connection or direct connection between the two components, and an indirect connection or indirect connection between the two components, unless expressly specified otherwise or contradicted by context.

FIG. 1 illustrates one embodiment of a tailpipe suspension assembly 10 of the present invention. The liner hanger assembly 10 includes a running tool 100 and a liner hanger 200.

As shown in FIG. 2, the running tool 100 includes a mandrel 110 that extends in an axial direction. In the embodiment shown in fig. 2, the mandrel 110 comprises a plurality of cylinders connected in series from top to bottom. It should be understood that more or fewer barrels may be used to form the mandrel 110, as desired.

The running tool 100 includes a setting drive assembly 120 that is sleeved over the mandrel 110. The hanging driving assembly 120 further includes a hydraulic mechanism 130 disposed outside the mandrel 110. As shown in fig. 2, the hydraulic mechanism 130 includes a hydraulic cylinder sleeve 131 that is sleeved over the mandrel 110. The lower end of the cylinder sleeve 131 is fixedly connected (e.g., by threads) to the outer sidewall of the mandrel 110, and the upper end is spaced apart from the mandrel 110, leaving an opening. The hydraulic mechanism 130 further comprises a hydraulic piston 132 which is sleeved outside the mandrel 110. The upper end of the hydraulic piston 132 is above the cylinder sleeve 131 and the lower end extends through the above-mentioned opening into the gap between the cylinder sleeve 131 and the spindle 110. The hydraulic piston 132 is slidably and sealingly engaged with the cylinder sleeve 131 and the mandrel 110. Thus, an upper hydraulic chamber and a lower hydraulic chamber may be partitioned within the cylinder sleeve 131 by the hydraulic piston 132. The upper hydraulic chamber may communicate with the mandrel interior space through a radially extending communication hole 114 in the mandrel 110. In addition, the lower hydraulic chamber communicates into the mandrel interior space through a pressure balancing passage provided on the mandrel 110. In the embodiment shown in fig. 2, the pressure equalization channel comprises a first channel 111 extending in the axial direction, communicating with the lower hydraulic chamber, and a second channel 112 extending in the radial direction, communicating with the first channel 111 and the mandrel inner space. A pressure holding ball seat 140 is provided inside the mandrel 110 between a position where the pressure balance passage communicates with the mandrel internal space and a position where the communication hole 114 communicates with the mandrel internal space. That is, the communication hole 114 communicates into the mandrel inner space above the pressure holding ball seat 140, and the pressure balancing passage communicates into the mandrel inner space below the pressure holding ball seat 140. Hereinafter, the pressure holding tee 140 will be described in detail.

As also shown in fig. 2, the upper end of the hydraulic piston 132 is outside of the cylinder sleeve 131 and is connected to the mandrel 110 by a third shear pin 134.

The sitting and hanging driving assembly 120 further comprises a sitting and hanging driving sleeve 133 sleeved outside the hydraulic piston 132, a tieback sleeve engaging sleeve 121 and a connecting sleeve 123. The inner side of the upper end of the tieback cylinder engaging sleeve 121 is configured with a limiting groove 121A. The upper end of the connecting sleeve 123 is fixedly connected with the mandrel 110, and the lower end of the connecting sleeve is spaced from the mandrel 110 to form a limiting gap. In the initial state (i.e., run-in state) shown in fig. 2, the upper end of the hydraulic piston 132 extends into the limit clearance. A limiting hole penetrating in the radial direction is formed at the lower end of the connection sleeve 123. A stopper 122 is provided in the stopper hole. In the state shown in fig. 2, the stopper 122 is supported on the inner side by the upper end of the hydraulic piston 132 so that it projects radially outward into the stopper groove 121A of the retraction cylinder engagement sleeve 121. Thus, the tieback barrel engagement sleeve 121 may be indirectly connected to the mandrel 110. An upward stepped surface is formed inside the tieback cylinder engaging sleeve 121. The seating and hanging driving sleeve 133 is located above and opposite to the stepped surface.

As shown in fig. 1, the lower end of the tieback cylinder engagement sleeve 121 abuts the upper end of the tieback cylinder 210 of the tailpipe suspension assembly 200 when the entire tailpipe suspension assembly 10 is assembled.

Thus, the pressure inside the mandrel 110 is substantially uniform before the pressure build-up ball 300 is run in. Due to the presence of the communication hole 114 and the pressure equalizing passage, the pressures in the upper and lower hydraulic chambers are the same. At this time, the pressures at the upper and lower ends of the hydraulic piston 132 are balanced, and thus, the hydraulic piston does not undesirably move and is not seated in advance. In the state that the pressure-building ball seat 140 is in the pressure-building state, the pressures in the mandrels 110 on the upper side and the lower side of the pressure-building ball seat 140 are different, and the upper pressure is obviously greater than the lower pressure. This results in the pressure in the upper hydraulic chamber also being significantly greater than the pressure in the lower hydraulic chamber. This causes the third shear pin 134 to shear and drive the hydraulic piston 132 downward. As the hydraulic piston 132 moves downward, the radially inner side of the stopper 122 is no longer supported, so that the stopper 122 moves radially inward and disengages from the stopper groove 121A. This causes the tieback barrel engagement sleeve 121 to separate from the mandrel 110. As the hydraulic piston 132 continues to move downwardly, the setting drive sleeve 133 connected to the hydraulic piston 132 moves downwardly with it and against the step surface on the tieback sleeve engagement sleeve 121. Thus, the tieback cylinder engagement sleeve 121 may be driven downward by the hydraulic piston 132 and thereby urge the tieback cylinder 210 downward (e.g., at a first pressure of about 30 kN).

The above-mentioned pressure build-up tee 140 will be described in detail with reference to fig. 2 to 6.

As shown in fig. 2, the hold pressure ball seat 140 includes a plurality of ball seat lobes 141. The respective ball seat lobes 141 are arranged annularly in the circumferential direction. With reference to fig. 5A to 5C, each ball seat flap 141 includes a tapered pressure holding ball engaging portion, and an extending portion disposed below the pressure holding ball engaging portion. The rubber layer 141B is preferably wrapped outside the ball seat flap 141 (in particular, outside the pressure holding ball joint) by vulcanization. An elastic rib engagement groove 141A extending in the axial direction is formed inside the extension portion. The lower end of the elastic rib engagement groove 141A extends in the axial direction to the lower end of the through ball seat flap 141.

The pressure build-up ball seat 140 further comprises an elastic sleeve 142 arranged below the ball seat flap 141. As shown in fig. 6, the lower end of the elastic sleeve 142 is configured as a complete ring body 142A, and the upper end is configured as a plurality of elastic ribs 142B extending upward in the axial direction from the ring body 142A. The elastic ribs 142B are provided corresponding to the respective ball seat lobes 141 and are spaced apart from each other in the circumferential direction. The elastic sleeve 142 is made entirely of an elastic material.

In the initial state shown in fig. 2, the ball seat flap 141 is mounted inside the mandrel 110. Under the restraining action of the mandrel 110, the ball seat flaps 141 are in a collapsed condition, together forming a complete ring. Since the rubber layer 141B is provided outside each ball seat flap 141, an effective press seal can be achieved between the adjacent ball seat flaps 141. This is very advantageous to avoid leakage when building pressure. In addition, the elastic sleeve 142 is installed below the ball seat flap 141, and is inserted into the ball seat flap 141 such that the upper end of each elastic rib 142B is elastically deformed radially inward. Each elastic rib 142B is preferably also fixedly connected with the corresponding ball seat flap 141 by a connection member such as a screw or bolt.

In the state shown in fig. 3, the pressure-building ball 300 is engaged with the circular ball seat formed by the ball seat flap 141. Due to the rubber layer 141B on the ball seat flap 141, the pressure build-up ball 300 can be in sealing engagement with the ball seat flap 141, and leakage is avoided. Therefore, effective pressure building can be realized. When the build-up pressure exceeds a certain threshold, the ball seat flap 141 is pushed to move downwards to the position shown in fig. 4. At this time, the ball seat flap 141 is opposed to the inner diameter-enlarged portion 113 of the mandrel 110. Since the outer side of the ball seat flap 141 is no longer restricted by the mandrel 110, the elastic ribs of the elastic sleeve 142 are expanded radially outward by the elastic force and bring the ball seat flap 141 together to move radially outward. Thereby, the ball seat flaps 141 are separated with respect to each other and the inner diameter of the ball seat they form is enlarged, so that the pressure build-up ball 300 can continue to fall down downhole, resulting in the end of the pressure build-up.

The above-described structure of the pressure building ball seat 140 can form a path in the mandrel 110 after the pressure building is completed. The hold-down ball seat 140 is advantageous for avoiding unintended hold-down due to downhole pressure surges.

In addition, as also shown in FIG. 2, the running tool 100 also includes a setting drive assembly 150. The setting drive assembly 150 is disposed below the setting drive assembly 120. The setting drive assembly 150 includes a setting drive block 151 that fits over the mandrel 110. The upper end of the setting drive block 151 is hinged relative to the mandrel 110 by a drive block connection 152, the lower end being a free end. In the initial state shown in fig. 1, the setting drive block 151 is inside the tieback barrel 210 of the running tool 200. Under the restraint of the tieback cylinder 210, the setting drive block 151 is in a collapsed state. When setting is required, the mandrel 110 is lifted upwards so that the setting drive block 151 moves out of the upper end of the tieback cartridge 210. The lower end of the setting drive block 151 is expanded radially outward to oppose the upper end face of the tieback cartridge 210 because it is no longer restrained. By pressing down the mandrel 110, the setting drive block 151 can press down the tieback cylinder 210 (e.g., at a second pressure of 200kN or more), thereby performing a setting operation.

Fig. 7 and 8 show a specific structure of the tail pipe hanger 200. The tailpipe suspension 200 includes a suspension body sleeve 240 extending in an axial direction for coupling with the mandrel 110 of the running tool 100, such as by a reverse threaded connection. The outer side of the suspension main body sleeve 240 is sleeved with a tieback cylinder 210, a packer assembly 220, a first anti-back sleeve 250 and a slip suspension mechanism 230 which are sequentially arranged from top to bottom.

The upper end of the tieback barrel 210 abuts the lower end of the tieback barrel engagement sleeve 121 of the running tool 100 and may be directly fixedly attached.

The packer assembly 220 includes an expansion sleeve 223 that is sleeved over a suspension body sleeve 240. The lower end of the expansion sleeve 223 is connected to the first anti-backup sleeve 250 and thereby indirectly connected to the slip hanging mechanism 230. The upper end of the expansion sleeve 223 is a free end, and a packing rubber cylinder 224 is arranged outside the upper end of the expansion sleeve 223. In the embodiment shown in fig. 7 and 8, the expansion sleeve 223 is spaced entirely from the suspension body sleeve 240, forming a clearance space therebetween. The packer assembly 220 also includes an expansion cone 221 that is sleeved outside the hanging body sleeve 240. The expansion cone 221 is connected at its upper end to the tieback 210 and at its lower end extends axially down into the clearance space between the expansion sleeve 223 and the suspension body sleeve 240.

In the initial state shown in fig. 7 and 8, a section of free space 223A is formed in the clearance space below the lower end of the expansion cone 221. The expansion cone 221 is connected to the expansion sleeve by a first shear pin 225. A setting inclined joint surface 221A is formed on the outer side surface of the expansion cone 221. Thus, when tieback cartridge 210 is moved downward by the first, relatively small pressure described above, first shear pin 225 does not shear. The tieback drum 210, expansion cone 221 and expansion sleeve 223 may move together downward and act on the slip suspension mechanism 230 below. In this process, the expansion sleeve 223 is always in the collapsed state. The packing rubber cylinders 224 are spaced from the outer wall or casing of the well. When the tieback cartridge 210 is moved downward by the second, greater pressure described above, the first shear pin 225 shears, allowing the expansion cone 221 to move axially downward relative to the expansion sleeve 223. At this point, the setting angled interface 221A is wedged between the upper end of the expansion sleeve 223 and the hanger body sleeve 240 to deform the upper end of the expansion sleeve 223 radially outwardly to move the packer rubber cartridge 224 radially outwardly into sealing engagement with the outer well wall for setting. The expansion sleeve 223 is preferably made of metal so that a certain force (much greater than that required to set a typical inflation compression packer) is required to force it to deform. In combination with the first shear pin 225, this is very effective in preventing the packer assembly 220 from setting unexpectedly, and in particular, preventing the packer assembly 220 from setting unexpectedly when the slip suspension mechanism 210 is set by being depressed.

In addition, a second anti-back-off 222 is provided between the expansion cone 221 and the suspension body sleeve 240. The second anti-back-out piece 222 is configured to only allow the expansion cone 221 to move downward relative to the suspension body sleeve. Thus, unintended unsetting can be avoided when the packer assembly 220 is set.

The first anti-back-off sleeve 250 is connected between the expansion sleeve 223 of the packer assembly 220 and the cone sleeve 231 of the slip suspension mechanism 230. A first anti-back-out piece 251 is provided between the first anti-back-out sleeve 250 and the suspension body sleeve 240. This allows the first anti-backup sleeve 250 and the structure connected thereto to move only downwards relative to the suspension body sleeve. This can prevent the packer assembly 220 from setting unintentionally and can also prevent the slip suspension mechanism 230 from tripping unintentionally.

The slip suspending mechanism 230 includes a slip fixing ring 233 sleeved and installed outside the suspending body sleeve 240, and the taper sleeve 231 sleeved outside the suspending body sleeve 240. A cone sleeve 231 is disposed above the slip retaining ring 233 and is spaced apart from the slip retaining ring 233. The lower end of the drogue 231 is configured with a sitting inclined engagement surface 231A. The upper end of the cone 231 is connected to a first anti-back-off sleeve 250 and thereby fixedly connected to the expansion sleeve 223 of the packer assembly 220. The slip suspension mechanism 230 also includes a plurality of slips 232 disposed outside of the suspension body sleeve 240. A plurality of slips 232 are circumferentially spaced apart from one another and axially located between slip retaining ring 233 and cone sleeve 231. The lower end of each slip 232 is hinged to a slip retaining ring 233 and the upper end of each slip is configured as a free end. Thus, when the tieback is moved downwardly by the first pressure and thereby drives the packer assembly 220 and the first anti-back sleeve 250 downwardly together, the drogue 231 is forced downwardly such that the setting inclined engagement surface 231A is wedged between the slips 232 and the suspension body sleeve 240 to move the upper ends of the slips 232 radially outwardly into engagement with the outer borehole wall to effect setting.

In addition, the slip suspension mechanism 230 includes a shear pin sleeve 234 that fits over the suspension body sleeve 240 and is disposed below the slip retaining ring 233. The shear pin sleeve 234 is connected to the suspension body sleeve 240 by a second shear pin 235. If the problem of the slip suspension mechanism 230 being set ahead occurs during the liner run in process, the string (running tool) may be lifted up to a certain tonnage to shear the second shear pin 235 so that the slips 232 may move down to unlock the suspension mechanism and lift the entire string (including the liner suspension assembly 10) out of the wellhead.

Thus, during downhole operations, the operator first runs the entire string including the liner hanger assembly 10 into the well. The tailpipe is attached to the lower end of the suspension body sleeve 240 of the tailpipe suspension 200. When run in place, the slip suspension mechanism 230 is set by injecting high pressure fluid into the pipe string, causing the hydraulic piston 132 to move downward, causing the tieback cylinder 210 to be driven downward by a first pressure. Thereafter, conventional cementing operations may be performed. After the cementing operation is complete, the running tool may be lifted up so that the setting drive assembly 150 is lifted out of the tieback cartridge 210. The running tool is then depressed at a second pressure and thereby drives the tieback 210 downward, effecting setting of the packer assembly 220. Thereafter, the running tool may continue to be lifted up, completing the entire liner hanging operation.

The hydraulic mechanism 130, etc., may all be raised uphole by raising the running tool, leaving only the tieback drum 210, packer assembly 220, and slip suspension mechanism 230 in the well. This enables tightness in the well to be ensured.

The tail pipe suspension device and the tail pipe suspension assembly are suitable for wells such as high-pressure gas wells and the like with high pressure resistance requirements on tail pipe well cementation tools, can greatly improve the pressure resistance and the sealing durability of the tools, and can effectively improve the running reliability of the tools.

While the invention has been described with reference to a preferred embodiment, various modifications may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In particular, the technical features mentioned in the embodiments can be combined in any way as long as there is no structural conflict. It is intended that the invention not be limited to the particular embodiments disclosed, but that the invention will include all embodiments falling within the scope of the appended claims.

Claims (12)

1. A tailpipe suspension, comprising:

a suspension body sleeve extending in an axial direction;

the slip hanging mechanism is sleeved outside the hanging main body sleeve;

the packer assembly is sleeved outside the suspension main body sleeve and connected to the slip suspension mechanism; and

the tie-back cylinder is sleeved outside the suspension main body sleeve and connected to the packer assembly;

wherein the tieback pipe moves downwards at a first pressure to drive the packer assemblies to move downwards together and drive the slip hanging mechanism to sit and hang;

wherein downward movement of the tieback at a second pressure greater than the first pressure drives the packer assembly to set.

2. The liner suspension of claim 1, wherein the slip suspension mechanism comprises:

the slip fixing ring is sleeved and arranged outside the sleeve of the suspension main body;

the conical sleeve is sleeved outside the suspension main body sleeve, the conical sleeve is arranged on the slip fixing ring and is spaced from the slip fixing ring, a sitting and hanging inclined joint surface is formed at the lower end of the conical sleeve, and the upper end of the conical sleeve is connected with the packer assembly; and

a plurality of slips disposed outside the suspension body sleeve, the plurality of slips being circumferentially spaced apart from one another and axially located between the slip retaining ring and the cone sleeve, a lower end of each slip being hinged to the slip retaining ring, an upper end of each slip being configured as a free end;

wherein when the tieback is moved downwardly at a first pressure and drives the packer assembly downwardly together, the taper sleeve moves downwardly such that the landing angled interface is interposed between the slips and the suspension body sleeve to cause the upper ends of the slips to move radially outwardly to effect landing.

3. The liner hanger of claim 2, wherein a first anti-back-off sleeve is connected between the upper end of the cone sleeve and the packer assembly, the first anti-back-off sleeve being configured to move only downward relative to the hanger body sleeve.

4. A liner hanger according to any one of claims 1 to 3, wherein the packer assembly comprises:

the expansion sleeve is sleeved outside the suspension main body sleeve, the lower end of the expansion sleeve is connected with the slip suspension mechanism, the upper end of the expansion sleeve is a free end, a packing rubber cylinder is arranged on the outer side of the upper end of the expansion sleeve, and a gap space is formed between the expansion sleeve and the suspension main body sleeve; and

the expansion cone is sleeved outside the suspension main body sleeve, the upper end of the expansion cone is connected with the tie-back cylinder, the lower end of the expansion cone axially extends into a gap space between the expansion sleeve and the suspension main body sleeve, a section of free space is formed in the gap space below the lower end of the expansion cone, the expansion cone is connected with the expansion sleeve through a first shearing pin, and a setting inclined joint face is formed on the outer side face of the expansion cone;

when the tieback cylinder moves downwards under the second pressure, the first shearing pin is sheared, so that the expansion cone can move downwards along the axial direction relative to the expansion sleeve, and the setting inclined joint face is inserted between the upper end of the expansion sleeve and the suspension main body sleeve, so that the packing rubber cylinder moves outwards in the radial direction to realize setting.

5. The tailpipe suspension apparatus according to claim 4, wherein a second anti-back off member is provided between the expansion cone and the suspension body sleeve, the second anti-back off member being configured to only allow the expansion cone to move downward relative to the suspension body sleeve.

6. A liner hanger assembly comprising a liner hanger according to any of claims 1 to 5, and a running tool configured to engage the liner hanger and to urge the tieback cylinder downwardly at the first and second pressures.

7. The tailpipe suspension assembly according to claim 6, wherein the running tool comprises:

a mandrel extending in an axial direction;

the sitting and hanging driving assembly is sleeved outside the mandrel and comprises a hydraulic mechanism, and the sitting and hanging driving assembly is constructed to push the tieback cylinder downwards under a first pressure; and

the setting driving assembly is sleeved outside the mandrel and arranged below the setting hanging driving assembly, and the setting driving assembly is constructed to push the tieback cylinder downwards under a second pressure.

8. The tailpipe suspension assembly according to claim 7, wherein the seat-hanging drive assembly comprises:

the hydraulic mechanism, the hydraulic mechanism includes:

the hydraulic cylinder sleeve is sleeved outside the mandrel and fixedly connected with the mandrel, and a gap is formed between the upper end of the hydraulic cylinder sleeve and the mandrel; and

a hydraulic piston disposed about said mandrel, said hydraulic piston having a lower end extending axially into a gap between said hydraulic cylinder sleeve and said mandrel and being in slidable sealing engagement with said hydraulic cylinder sleeve and mandrel, said hydraulic piston defining an upper hydraulic chamber and a lower hydraulic chamber within said hydraulic cylinder sleeve;

the sitting and hanging driving sleeve is sleeved outside the upper end of the hydraulic piston and is fixedly connected with the hydraulic piston; and

the lower end of the tieback cylinder joint sleeve is abutted to the upper end of the tieback cylinder;

wherein when fluid enters the upper hydraulic chamber of the cylinder sleeve, the hydraulic piston is driven to move downwardly such that the landing drive sleeve pushes the tieback cylinder engagement sleeve downwardly and further pushes the tieback cylinder downwardly.

9. The liner hanger assembly of claim 8, wherein the running tool further comprises a hold-down ball seat disposed within the mandrel, wherein the mandrel is configured with a pressure balancing passage having one end communicating into the lower hydraulic chamber of the cylinder barrel and another end communicating into the interior of the mandrel below the hold-down ball seat.

10. The tailpipe suspension assembly according to claim 9, wherein the hold pressure ball seat comprises:

a plurality of ball seat pieces arranged annularly in a circumferential direction independently of each other, each ball seat piece having an elastic rib engagement groove formed at an inner side of a lower end thereof; and

an elastic sleeve having a lower end configured as a complete ring body and an upper end configured as a plurality of elastic ribs extending upward in an axial direction from the ring body, the plurality of elastic ribs being arranged spaced apart from each other in a circumferential direction, an upper end of each elastic rib being insertable into an elastic rib engagement groove of each ball seating flap in a radially inwardly contracted state;

during the running process, the ball seat flaps are arranged in the mandrel, the ball seat flaps are folded relative to each other through the inner wall of the mandrel to form a complete ring shape, and the elastic ribs of the elastic sleeve are in a folded state; upon pressure build-up, the plurality of ball seat lobes move downwardly relative to the mandrel to an inner diameter enlargement of the mandrel, and under the resiliency of the respective resilient ribs, the respective ball seat lobes move radially outwardly such that the inner diameter defined by the respective ball seat lobes increases.

11. The tailpipe suspension assembly according to claim 10, wherein an outer surface of each ball seat lobe is formed with a rubber layer.

12. A tailpipe suspension assembly according to any of claims 7 to 11, wherein the setting drive assembly comprises a setting drive block sleeved outside the mandrel, the upper end of the setting drive block being hinged relative to the mandrel by a drive block connection, the lower end of the setting drive block being a free end;

in the running-in process, the setting driving assembly is located in the tieback cylinder, so that the setting driving block is in a folded state, when the packer assembly needs to be set, the mandrel is lifted up, the setting driving block moves out of the upper end of the tieback cylinder, the lower end of the setting driving block radially expands outwards to be opposite to the upper end face of the tieback cylinder, and the mandrel is pressed downwards so that the tieback cylinder is pressed downwards through the setting driving block.

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