CN112227992B - Double-hanging double-sealing high-temperature-resistant expansion hanger - Google Patents

Abstract

The invention discloses a double-hanging double-sealing high-temperature-resistant expansion hanger, which comprises an expansion hanging cylinder, a slip sitting and hanging mechanism, a hanging sealing mechanism, an expansion mechanism, a back-off mechanism and a variable-buckle joint, wherein the expansion hanging cylinder is connected with the slip sitting and hanging mechanism; the slip sitting and hanging mechanism comprises a central tube, an upper expansion cone and a hydraulic mechanism, the hanging sealing mechanism comprises a metal slip and a sealing cylinder which are fixed on the outer surface of the expansion hanging cylinder, the expansion mechanism consists of an expansion mandrel, a lower expansion cone and a fixed nipple, the expansion mechanism is arranged in an expansion starter of the expansion hanging cylinder in advance, and the back-off mechanism is positioned at the lower part of the expansion mechanism and consists of a bearing mandrel, a bearing, a spring sleeve, a spring and a back-off joint. The invention can realize double suspension of the metal slips and the sealing cylinder and double sealing of the metal and the rubber, effectively improve the suspension force of the expansion hanger, obviously improve the sealing capability of the expansion hanger under the high temperature condition, and is suitable for tail pipe completion operation of a thermal production well, a deep well and an ultra-deep well under the high temperature well condition.

Description

Double-hanging double-sealing high-temperature-resistant expansion hanger

Technical Field

The invention relates to a double-hanging double-sealing high-temperature-resistant expansion hanger in the field of petroleum drilling and completion tools.

Background

The liner suspension well cementation process is the most common well completion method in deep well, side well and deepened well cementation, can save the sleeve, reduce annulus flow resistance and displacement pressure in cement injection construction, simplify well structure, facilitate the loading of liner strings, and solve the well completion problem of deep well and complex well.

Currently, liner hangers are classified into slip type liner hangers and expansion type liner hangers according to their seat hanging manner. In general, the slip type tail pipe hanger has the problems of unreliable seat hanging, small seat hanging drift diameter and unsatisfactory sealing effect; the expansion type tail pipe hanger is generally hung by adopting a hydraulic mode to realize the expansion seat of the hanger, so that the rubber cylinder is extruded between double-layer sleeves to realize sealing, the hanging and hanging modes are single, and the risk that rubber is aged and failed at high temperature and is difficult to release by reversely buckling still exists by means of single rubber sealing under the high-temperature conditions of a deep well and a thermal production well. For example, chinese patent CN101161982B discloses a hydraulic expansion liner hanger. The hydraulic expansion type tail pipe hanger consists of a feeding joint, a cement rubber plug, a central pipe, an expansion plug, a clamp spring, a shear pin, a sealing rubber plug, a rubber plug guide pipe, a blocking ring, a lower connecting pipe and the like. The upper end of the feeding connector is provided with threads which can be connected with a drilling tool. The outer wall of the lower end of the feeding joint is connected with the left-handed thread of the expansion pipe; the inner wall of the lower end of the feeding joint is connected with the central pipe through screw threads. The lower end of the central tube is fixed with a sealing rubber plug through a shear pin. The inner diameter of the sealing rubber plug is 8-20 mm smaller than that of the central tube. The expansion plug is in dynamic sealing fit with the central tube at the lower end in the annular space between the central tube and the expansion tube, and can slide on the central tube; the clamp spring is annular and is clamped in a groove on the outer wall of the lower end of the central tube; the rubber plug conduit is connected to the lower end of the expansion pipe; the lower end of the rubber plug conduit is in threaded connection with a lower connecting pipe, the lower end of the lower connecting pipe is provided with threads, and the lower connecting pipe has the function of connecting a tail pipe string which needs to be hung underground. The blocking ring sits on the inner shoulder of the lower connecting tube. The diameter of the upper central hole of the blocking ring is the same as the outer diameter of the lower end of the sealing rubber plug, and the diameter of the lower central hole of the blocking ring is smaller than the outer diameter of the lower end of the sealing rubber plug. In order to make the expansion pipe and the sleeve more firmly hung, the outer side of the expansion pipe is provided with at least one annular bulge, the section of the annular bulge is trapezoid, and the outer diameter of the annular bulge is the same as the diameter of the end part of the expansion pipe. The outer wall of the expansion pipe is directly sealed with the inner wall of the sleeve; rubber sealing can also be adopted, namely, a rubber ring is sleeved on the outer wall of the expansion pipe; or the outer wall of the expansion pipe is sleeved with a metal and rubber combined sealing ring, and the metal and rubber combined sealing is adopted. Compared with the prior art, the hydraulic expansion type liner hanger is mainly characterized in that: the expansion plug is pushed to expand the expansion pipe from bottom to top by utilizing the action of hydraulic pressure, and the expansion pipe is tightly contacted with the inner wall of the sleeve to suspend the tail pipe. The structural design is greatly improved, but a back-off releasing mechanism is not designed, the risks of limited length of a hanging tail pipe and difficult pipe string running-in exist, meanwhile, a single hanging mode is adopted for operation, and effective hanging is difficult under the condition of insufficient hydraulic pressure or no collision pressure.

Disclosure of Invention

The invention aims to solve the technical problems of the existing expansion hanger, and provides a double-hanging double-sealing high-temperature-resistant expansion liner hanger, which meets the construction requirements of liner cementing of oil and gas wells, is particularly suitable for liner completion operation under special working conditions of deep wells and thermal recovery wells, and reduces the potential safety hazards of the expansion liner hanger in the aspects of hydraulic sitting and hanging, rubber sealing and back-off release.

The invention solves the technical problems by adopting the technical scheme that:

a double-hanging double-sealing high-temperature-resistant expansion hanger comprises an expansion hanging cylinder, a slip sitting and hanging mechanism, a hanging sealing mechanism, an expansion mechanism and a back-off mechanism;

The expansion suspension cylinder is an expandable short joint, and the top and the bottom of the expansion suspension cylinder are respectively provided with an expansion outlet which is expanded in advance and takes the shape of an upper bell mouth and an expansion starter which is in the shape of a lower bell mouth; the bottom of the expansion suspension cylinder is fixedly connected with the tail pipe through a buckling connector;

The slip sitting and hanging mechanism comprises a central tube, an upper expansion cone and a hydraulic mechanism, wherein the hydraulic mechanism is connected with the upper expansion cone, the upper expansion cone is provided with a downward expansion cone surface and is preset at an expansion outlet of an expansion hanging cylinder, the upper expansion cone and the central tube form axial sliding sealing fit, a liquid inlet communicated with the central tube is arranged on the hydraulic mechanism, and the hydraulic mechanism is of a one-stage or multi-stage hydraulic structure; a limiting structure is arranged on the central tube at the lower stroke dead point of the upper expansion cone and is in limiting fit with the upper expansion cone which axially moves on the central tube;

the suspension sealing mechanism comprises a metal slip and a sealing cylinder which are fixed on the outer surface of the expansion suspension cylinder, wherein the metal slip consists of a plurality of slip blocks which are circumferentially arranged, and a circulating channel is preset between every two adjacent slip blocks;

the expansion mechanism comprises an expansion mandrel and a lower expansion cone, the expansion mechanism is pre-arranged in an expansion starter of the expansion suspension cylinder, the expansion mandrel and the lower expansion cone are of an integrated hollow structure or of a combined sleeve hollow structure, and the outer surface of the lower expansion cone is provided with an upward expansion cone surface; the upper part of the expansion mandrel is fixedly connected with the central tube;

The back-off mechanism is positioned at the lower part of the expansion mechanism and comprises a hollow rubber plug, a bearing mandrel, a bearing, a spring sleeve, a spring, a back-off joint and a variable-buckle joint; the bearing mandrel is provided with a back-off joint, the back-off joint is provided with a back-off thread, and the back-off joint is connected with the variable-speed joint in a matched manner through the back-off thread; the back-off joint and the bearing mandrel form circumferential synchronous rotation and circumferential sliding fit; the upper part of the bearing mandrel is fixedly connected with the expansion mandrel, and a bearing is arranged between the spring sleeve on the bearing mandrel and the expansion mandrel; the hollow rubber plug is pinned at the bottom of the bearing mandrel;

The expansion hanging cylinder and the buckling connector are sequentially and fixedly connected from top to bottom to form an outer tubular column; the hydraulic cylinder mechanism, the central tube, the expansion mandrel, the bearing mandrel and the hollow rubber plug are sequentially and fixedly connected from top to bottom to form an inner tubular column.

The above scheme further includes:

the sealing cylinder is formed by matching and combining one or more of a rubber cylinder, a rubber cylinder-trapezoid metal ring or a rubber cylinder-zigzag metal ring.

The rubber cylinder is made of high-temperature resistant fluororubber, and the outer surface of the expansion suspension cylinder at the position of the rubber cylinder is provided with a metal protrusion in limit fit with the rubber cylinder.

The trapezoid metal ring is of an outer wide and inner narrow structure, the trapezoid metal ring and the zigzag metal ring are made of soft metal materials, and the outer diameter of the trapezoid metal ring is slightly smaller than that of the rubber cylinder.

Slip teeth are machined on the slip blocks, and adjacent slip blocks are fixed through connecting ribs and fixing rings; the connecting ribs are of open non-closed-loop structures, and the outer diameters of the connecting ribs are smaller than the outer diameters of the slip segments; the outer diameter of the fixed ring is slightly smaller than the outer diameter of the slip segments.

The adjacent slip segments are fixed through connecting ribs at the lower part and the middle part, and the upper parts of the slip segments are fixed through fixing rings.

The back-off mechanism further comprises a rubber plug rod, the hollow rubber plug is fixedly arranged at the bottom of the rubber plug rod through a pin, the rubber plug rod is connected with the bearing mandrel, and the hollow rubber plug is arranged in a tail pipe connected with the expansion hanger in advance.

The suspension sealing mechanism further comprises a fixed nipple, and the expansion mandrel and the lower expansion cone are fixedly connected with the central tube above through the fixed nipple.

The invention has the main advantages that:

(1) The double-hanging double-sealing mode operation of metal slips and sealing cylinders and double-hanging double-sealing of metal and rubber materials is adopted, so that the hanging and sealing performance of the expansion hanger is effectively improved;

(2) The sealing cylinder adopts a sealing mode of combining the high-temperature resistant fluororubber cylinder, the trapezoid metal ring and the zigzag metal ring, improves the sealing capability under the high-temperature condition, and is suitable for tail pipe completion operation of a thermal production well, a deep well and an ultra-deep well under the high-temperature well condition.

(3) When the back-off mechanism with the bearing structure is used for carrying out back-off with neutral point load, the back-off threads bear smaller axial load, so that back-off operation is facilitated, and the success rate of the back-off operation is improved.

(4) By adopting the operation mode that the upper expansion cone and the lower expansion cone firstly sit and hang the slips and then sit and hang the expansion hanging cylinder, the mechanical sitting and hanging force can be increased, the hydraulic expansion force can be reduced, and the operation risk can be reduced.

Drawings

FIG. 1 is a cross-sectional view of the general structure of an embodiment of a dual-suspension dual-seal high temperature resistant expansion hanger of the present invention;

FIG. 2 is a schematic illustration of a metal slip construction according to one embodiment of the present invention;

FIG. 3 is a schematic view of a seal cartridge segment according to an embodiment of the present invention;

FIG. 4 is a schematic view illustrating a down status of an embodiment of the present invention;

FIG. 5 is a schematic view showing a back-off state before cementing according to an embodiment of the present invention;

FIG. 6 is a schematic illustration of a setting and metal slip in one embodiment of the present invention;

FIG. 7 is a schematic view of a sitting and hanging state according to an embodiment of the present invention;

fig. 8 is a schematic view of a tubular string after construction according to an embodiment of the present invention.

Wherein: 1. the hydraulic system comprises an expansion hanging cylinder 2, a metal slip 201, slip blocks 202, slip teeth 203, connecting ribs 204, a fixing ring 205, a circulating channel 3, a sealing cylinder 301, a rubber cylinder 302, a trapezoid metal ring 303, a zigzag metal ring 4, an upper expansion cone 5, a lower expansion cone 6, a hydraulic cylinder mechanism 7, a central pipe 8, a fixing short joint 9, an expansion mandrel 10, a bearing mandrel 11, a bearing 12, a spring sleeve 13, a spring 14, a back-off joint 15, a variable-off joint 16, a tail pipe 17, a rubber plug rod 18, a hollow rubber plug 19, a drill rod 20, a drill rod rubber plug 21, a technical sleeve 22, an expansion starter 23, an expansion outlet 24, a slip hanging mechanism 25, a hanging sealing mechanism 26, an expansion mechanism 27 and a back-off mechanism.

Detailed Description

The invention will now be further described with reference to the accompanying drawings.

Example 1

Referring to fig. 1, a double-hanging double-sealing type high-temperature-resistant expansion hanger comprises an expansion hanging cylinder 1, a slip sitting and hanging mechanism 24, a hanging sealing mechanism 25, an expansion mechanism 26 and a back-off mechanism 27. Wherein:

The expansion hanging cylinder 1 is an expandable short joint, and the top and the bottom of the expansion hanging cylinder are respectively provided with an expansion outlet 23 which is expanded in advance and takes the shape of an upper bell mouth and an expansion starter 22 which is in the shape of a lower bell mouth; the bottom of the expansion hanging cylinder 1 is fixedly connected with a tail pipe 16 through a buckling joint 15.

The slip sitting and hanging mechanism 24 comprises a central tube 7, an upper expansion cone 4 and a hydraulic mechanism 6, wherein the hydraulic mechanism 6 is connected with the upper expansion cone 4, the upper expansion cone 4 is provided with a downward expansion cone surface and is preset at an expansion outlet 23 of the expansion hanging cylinder 1, the upper expansion cone 4 and the central tube 7 form axial sliding sealing fit, a liquid inlet hole communicated with the central tube is formed in the hydraulic mechanism 6, and the hydraulic mechanism 7 is of a one-stage or multi-stage hydraulic structure; a limiting structure is arranged on the central tube 7 at the lower stroke dead point of the upper expansion cone 4, and the limiting structure is in limiting fit with the upper expansion cone 4 axially moving on the central tube 7.

The hanging sealing mechanism 25 comprises a metal slip 2 and a sealing barrel 3 which are fixed on the outer surface of the expansion hanging barrel 1, wherein the metal slip 2 is composed of a plurality of slip blocks 201 which are arranged in a circumferential mode, and a circulating channel 205 is preset between every two adjacent slip blocks 201.

The expansion mechanism 26 comprises an expansion mandrel 9 and a lower expansion cone 5, the expansion mechanism 26 is preset in the expansion starter 22 of the expansion suspension cylinder 1, the expansion mandrel 9 and the lower expansion cone 5 are of an integrated hollow structure or of a combined sleeve hollow structure, and the outer surface of the lower expansion cone 4 is provided with an upward expansion cone surface; the upper part of the expansion mandrel 9 is fixedly connected with the central tube 7.

The back-off mechanism 27 is positioned at the lower part of the expansion mechanism 26 and comprises a hollow rubber plug 18, a bearing mandrel 10, a bearing 11, a spring sleeve 12, a spring 13, a back-off joint 14 and a back-off joint 15; the bearing mandrel 10 is provided with a back-off joint 14, the back-off joint 14 is provided with a back-off thread, and the back-off joint 14 is connected with a variable-buckle joint 15 in a matching way through the back-off thread; the back-off joint 14 and the bearing mandrel 10 form circumferential synchronous rotation and circumferential sliding fit; a spring 13 and a spring sleeve 12 are arranged on a bearing mandrel 10 at the upper part of the back-off joint 14, the spring 13 is positioned between the bearing mandrel 10 and the spring sleeve 12, the upper part of the bearing mandrel 10 is fixedly connected with an expansion mandrel 9, and a bearing 11 is arranged between the spring sleeve 12 on the bearing mandrel 10 and the expansion mandrel 9; the hollow rubber plug 18 is pinned to the bottom of the bearing mandrel 10.

The expansion hanging cylinder 1 and the buckling joint 15 are sequentially and fixedly connected from top to bottom to form an outer pipe column; the hydraulic cylinder mechanism 6, the central tube 7, the expansion mandrel 9, the bearing mandrel 10 and the hollow rubber plug 18 are sequentially and fixedly connected from top to bottom to form an inner tubular column.

Example 2

Referring to fig. 3, the method further comprises the following steps on the basis of the embodiment 1:

The sealing cylinder 3 is formed by matching and combining one or more of a rubber cylinder 301, a rubber cylinder 301-trapezoid metal ring 302 or a rubber cylinder 301-zigzag metal ring 303. Wherein the rubber cylinder 301 adopts high temperature resistant fluororubber, and the outer surface of the expansion suspension cylinder 1 at the position of the rubber cylinder 301 is provided with a metal protrusion in limit fit with the rubber cylinder 301. The trapezoid metal ring 302 has a structure with a wide outside and a narrow inside, the trapezoid metal ring 302 and the zigzag metal ring 303 are made of soft metal materials, and the outer diameter of the trapezoid metal ring is slightly smaller than that of the rubber cylinder 301.

Referring to fig. 2, slip segments 202 are formed on the slip segments 201, and adjacent slip segments 201 are fixed by connecting ribs 203 and fixing rings 204; the connecting ribs 203 are of an open non-closed loop structure, and the outer diameter of the connecting ribs 203 is smaller than the outer diameter of the slip segments 201; the outer diameter of the retaining ring 204 is slightly smaller than the outer diameter of the slip segments 201. Adjacent slip segments 201 are fixed by connecting ribs 203 at the lower part and the middle part, and the upper part of the slip segments 201 is fixed by a fixing ring 204.

Further, the back-off mechanism 27 further comprises a rubber plug rod 17, the hollow rubber plug 18 is fixedly arranged at the bottom of the rubber plug rod 17 through a pin, the rubber plug rod 17 is connected with the bearing mandrel 10, and the hollow rubber plug 18 is pre-arranged in a tail pipe 16 connected with the expansion hanger. The hanging sealing mechanism 25 further comprises a fixing nipple 8, and the expansion mandrel 9 and the lower expansion cone 5 are fixedly connected with the central tube 7 above through the fixing nipple 8.

Typical example 3

Referring to fig. 1 to 3, a double-hanging double-sealing type high temperature resistant expansion hanger comprises an expansion hanging cylinder 1, a slip setting and hanging mechanism 24, a hanging sealing mechanism 25, an expansion mechanism 26, a back-off mechanism 27, a variable-buckle joint 15 and tail pipe 16 components.

The expansion hanging cylinder 1 is an expandable casing nipple, the top and the bottom of the expansion hanging cylinder are respectively provided with an expansion outlet 23 which is expanded in advance and takes the shape of an upper bell mouth and an expansion starter 22 which is in the shape of a lower bell mouth, and an upper expansion cone 4 of a slip sitting and hanging mechanism 24 is preset in the expansion outlet 23. The tail pipe 16 is in threaded connection with an expansion initiator 22 at the bottom of the expansion suspension cartridge 1 through a stab joint 15.

The hanging sealing mechanism 25 mainly comprises a metal slip 2 and a multi-section sealing cylinder 3, wherein the metal slip 2 and the sealing cylinder 3 are fixed on the outer surface of the expansion hanging cylinder 1. The metal slip 2 is formed by arranging a plurality of slip blocks 201 in a circumferential manner, and slip teeth 202 are machined on the slip blocks 201. Adjacent slip segments 201 are fixed by connecting ribs 203 at the lower part and the middle part, and the upper part of the slip segments 201 is fixed by a fixing ring 204. The outer diameter of the fixing ring 204 is slightly smaller than the outer diameter of the slip segments 201, the connecting ribs 203 can be of an open non-closed loop structure, and the outer diameter of the connecting ribs 203 is smaller than the outer diameter of the slip segments 201. Circulation channels 205 are present at the connection ribs 203 between adjacent slip segments 201.

The sealing cylinder 3 is formed by matching and combining a rubber cylinder 301, a trapezoid metal ring 302 and a zigzag metal ring 303 in form, so as to form a metal and rubber double composite sealing material. The rubber cylinder 301 adopts high temperature resistant fluororubber, the outer surface of the expansion suspension cylinder 1 at the position of the rubber cylinder 301 is provided with metal bulges, the trapezoid metal ring 302 is of a structure with wide outside and narrow inside, the trapezoid metal ring 302 and the zigzag metal ring 303 adopt soft metal materials such as brass,

The outer diameters of the trapezoid metal rings 302 and the zigzag metal rings 303 are slightly smaller than the outer diameter of the rubber cylinder 301, and the trapezoid metal rings 302 positioned between the upper adjacent rubber cylinders 301 and the lower adjacent rubber cylinders 301 are of a structure with wide outside and narrow inside, so that the rubber cylinders 301 are not easy to break off in the expansion process of the expansion suspension cylinder 1. After expansion, the sealing cylinder 3 is compressed between the expansion suspension cylinder 1 and the technical sleeve 21, forming a metal and rubber dual material seal.

The slip sitting and hanging mechanism 24 comprises a central tube 7, an upper expansion cone 4 and a hydraulic mechanism 6, wherein the upper expansion cone 4 positioned on the central tube 7 is arranged at the expansion outlet 23 of the expansion hanging cylinder 1, the upper expansion cone 4 is provided with a downward expansion cone surface, and the upper expansion cone 4 is sleeved on the central tube 7 and can axially move. The lower part of the central tube 7 is provided with a limiting structure for limiting the upper expansion cone 4 axially moving on the central tube 7.

The hydraulic cylinder mechanism 6 is connected with the central tube 7, and the upper expansion cone 4 is arranged below the hydraulic cylinder mechanism 6 and is preset in the expansion outlet 23. The hydraulic cylinder mechanism 6 is provided with a liquid inlet hole, the hydraulic cylinder mechanism 6 can be of a multi-stage hydraulic cylinder structure, the number of hydraulic cylinder stages is set according to the sitting and hanging pressure of the metal slips 2, and the construction operation safety is ensured.

The expansion mechanism 26 is composed of an expansion mandrel 9, a lower expansion cone 5 and a fixed nipple 8. The lower expansion cone 5 is of a cone column-shaped through hole structure, is sleeved on the expansion mandrel 9, and an upward expansion conical surface is arranged on the surface of the lower expansion cone 5. The lower part of the fixed nipple 8 is fixedly connected with the expansion mandrel 9, the upper part of the fixed nipple 8 is fixedly connected with the central tube 7, and the lower expansion cone 5 is fixed on the expansion mandrel 9. The expansion mechanism 26 is preset in the expansion starter 22 of the expansion suspension cylinder 1 and is used for expanding the expansion suspension cylinder 1 to realize liner suspension sealing.

The back-off mechanism 27 is positioned at the lower part of the expansion mechanism 26 and consists of a bearing mandrel 10, a bearing 11, a spring sleeve 12, a spring 13 and a back-off joint 14. The bearing mandrel 10 is provided with a back-off joint 14, the back-off joint 14 rotates along with the bearing mandrel 10 and can axially move on the bearing mandrel 10, and the back-off joint 14 is provided with back-off threads. A spring 13 and a spring sleeve 12 are sleeved on the bearing mandrel 10 at the upper part of the back-off joint 14, the spring 13 is positioned between the bearing mandrel 10 and the spring sleeve 12, and the spring sleeve 12 can compress the spring 13 and axially move along the bearing mandrel 10. The upper part of the bearing mandrel 10 is fixedly connected with the expansion mandrel 9 through threads, a bearing 11 is arranged between a spring sleeve 12 on the bearing mandrel 10 and the expansion mandrel 9, and a back-off joint 14 is matched and connected with a changing joint 15 through back-off threads.

The double-hanging double-sealing high-temperature-resistant expansion hanger is characterized in that a hollow rubber plug 18 preset in a tail pipe 16 is connected to the bottom of a bearing mandrel 10 through a rubber plug rod 17, the hollow rubber plug 18 is in pin connection with the rubber plug rod 17, the inner diameter of the hollow rubber plug 18 is smaller than the outer diameter of a drill rod rubber plug, when the drill rod rubber plug enters the hollow rubber plug 18, the drill rod rubber plug is blocked from descending, shearing occurs under the condition of pressure difference, and the pin is cut off.

In the hanging sealing mechanism 25, a rubber cylinder 301 is made of high-temperature resistant fluororubber, a metal bulge can be processed on the outer surface of the expansion hanging cylinder 1 at the position of the rubber cylinder 301, and a trapezoid metal ring 302 and a zigzag metal ring 303 are made of soft metal materials such as brass.

The double-hanging double-sealing high-temperature-resistant expansion hanger comprises an outer pipe column, an expansion hanging cylinder 1, a buckling joint 15 and a tail pipe 16 which are sequentially connected through threads, and a rubber plug rod 17, a bearing mandrel 10, an expansion mandrel 9, a fixed nipple 8, a central pipe 7, a hydraulic cylinder mechanism 6 and a feeding drill pipe 19 which are sequentially connected through threads form an inner pipe column.

The operation procedure of the expansion hanger of the present invention mainly comprises the following steps: the tail pipe 16 is put in, buckled reversely, the metal slips 2 are hung on the hanging barrel 1.

Step one: the tailpipe 16 is run in. Referring to fig. 4, when the tail pipe 16 is run in the field, the assembled expansion hanger is connected to the upper portion of the tubular string of the tail pipe 16, and then the tubular string of the tail pipe 16 is safely run in by the connection of the drill pipe 19. The blocking phenomenon occurs in the tubular column running-in process of the tail pipe 16, and the tubular column can be run-in an auxiliary manner by lifting and lowering the movable drill rod 19.

Step two: and (5) circularly and reversely buckling. Referring to fig. 5, after the liner 16 is run into the designed well depth, a circulation flushing is performed, and a back-off release operation is performed prior to the cementing operation. During back-off operation, the suspension weight of the drilling tool is adjusted, a neutralization point of the drilling tool is found, and the pipe column is rotated forward to back-off. Due to the influence of the wellbore track and friction factors, even if the well head drilling tool hanging weight is adjusted to find the neutral point, the back-off mechanism of the expansion hanger may be in an up-or down-pressing state, and at the neutral point load position, the drilling tool is up-or down-pressed to a certain load, and because the back-off joint 14 can axially slide on the bearing mandrel 10, the spring housing 12 can compress the spring 13 to move up and down, thereby absorbing a certain load, and the bearing mandrel 10 has a certain movable stroke, so that the back-off thread bears a small axial force. The forward drill rod 19, the bearing mandrel 10 drives the back-off joint 14 to rotate, the spring 13 and the spring sleeve 12 relatively rotate with the expansion mandrel 9 through the bearing 11, so that the back-off threads connected with the back-off joint 14 and the variable-buckle joint 15 are disconnected, and the releasing operation is completed. The back-off mechanism 27 of the present invention reduces back-off thread axial forces relative to conventional back-off thread release, facilitates finding out neutral point loads, and improves back-off success rate.

Step three: the slips are hung. Referring to fig. 1 and 6, after the reverse buckling of the expansion hanger is finished, the lower expansion cone 5 on the expansion mandrel 9 contacts with the conical surface of the expansion starter 22 of the expansion hanging cylinder 1, and cementing and drilling rod rubber plugs 20 are put into place according to the normal procedure. When the drill rod rubber plug 20 is blocked by the hollow rubber plug 18 which is displaced to the bottom of the rubber plug rod 17, internal pressure is formed, hydraulic pressure is transmitted to the hydraulic cylinder mechanism 6, the hydraulic cylinder mechanism 6 pushes the upper expansion cone 4 to move downwards along the central tube 7, and the expansion outlet 23 and the metal slips 2 at the upper part of the expansion hanging cylinder 1 are sealed in an expanding mode. The slip segments 201 do not expand when the metal slip 2 is expanded, but the ribs 203 connecting the slip segments 201 are stretched and the slip segments 202 on the slip segments 201 are pressed against the inner wall of the technical sleeve 21. When the upper expansion cone 4 descends to the limit structure at the lower part of the central tube 7, the metal slips 2 finish sitting and hanging.

The hydraulic cylinder mechanism 6 is of a multi-stage hydraulic cylinder structure, and the number of hydraulic cylinder stages of the hydraulic cylinder mechanism 6 can be adjusted according to the sitting and hanging pressure of the metal slips 2. After the metal slips 2 are set, circulation channels 205 are still present at the connecting ribs 203 between the slip segments 201, allowing fluid communication. And continuing to hold pressure to shear the hollow rubber plug 18, separating the hollow rubber plug 18 from the rubber plug rod 17, and continuing to be displaced and downwards to the well cementation accessory to collide and press.

Step four: the hanger is hung on the seat. Referring to fig. 7, after the hollow rubber plug 18 is bumped and pressed, the wellhead continues to hold pressure to the design pressure, when the suspended weight of the wellhead drilling tool is lowered, the drilling tool is lifted up, the expansion suspension cylinder 1 is expanded by pushing the lower expansion cone 5 by hydraulic pressure, and the sealing cylinder 3 on the suspension sealing mechanism 25 is expanded and extruded between the expansion suspension cylinder 1 and the technical sleeve 21, so that a powerful mechanical seal made of metal and rubber is formed. When the lower expansion cone 5 expands to the sealing cylinder 3, the sitting and hanging pressure of the lower expansion cone is higher than the internal pressure of the expansion and hanging cylinder 1 due to the extrusion of the sealing cylinder 3, and in order to avoid the excessive expansion pressure, the sitting and hanging metal slips 2 can provide mechanical supporting force, so that the sitting and hanging expansion pressure of the sealing cylinder 3 is reduced.

Step five: and releasing the well completion. Referring to fig. 8, when the lower expansion cone 5 completely completes the expansion of the expansion suspension cylinder 1, the lower expansion cone 5 releases from the expansion suspension cylinder 1 under the action of hydraulic and mechanical lifting force, the wellhead is decompressed, the expansion of the expansion suspension cylinder 1 is completed, and after the superfluous cement paste is circulated out of the wellhead, the drilling tool is lifted up for completion.

The double-hanging double-sealing type high-temperature-resistant expansion hanger can realize double hanging of the metal slips 2 and the sealing cylinder 3 and double sealing of metal and rubber after sitting and hanging, effectively improves the hanging force of the expansion hanger, remarkably improves the sealing capacity of the expansion hanger under the high-temperature condition, and is suitable for tail pipe completion operation of a thermal production well, a deep well and an ultra-deep well under the high-temperature well condition.

Claims (6)

1. The double-hanging double-sealing high-temperature-resistant expansion hanger comprises an expansion hanging cylinder (1), a slip sitting and hanging mechanism (24), a hanging sealing mechanism (25) and an expansion mechanism (26), and is characterized by further comprising a back-off mechanism (27); the expansion hanging cylinder (1) is an expandable short joint, and the top and the bottom of the expansion hanging cylinder are respectively provided with an expansion outlet (23) which is expanded in advance and takes the shape of an upper bell mouth and an expansion starter (22) which is in the shape of a lower bell mouth; the bottom of the expansion hanging cylinder (1) is fixedly connected with a tail pipe (16) through a buckling joint (15); the slip sitting and hanging mechanism (24) comprises a central tube (7), an upper expansion cone (4) and a hydraulic cylinder mechanism (6), wherein the hydraulic cylinder mechanism (6) is connected with the upper expansion cone (4), the upper expansion cone (4) is provided with a downward expansion cone and is preset at an expansion outlet (23) of the expansion hanging cylinder (1), the upper expansion cone (4) and the central tube (7) form axial sliding sealing fit, a liquid inlet communicated with the central tube is arranged on the hydraulic cylinder mechanism (6), and the hydraulic cylinder mechanism (6) is of a one-stage or multi-stage hydraulic cylinder structure; A limiting structure is arranged on the central tube (7) at the lower stroke dead point of the upper expansion cone (4), and is in limiting fit with the upper expansion cone (4) axially moving on the central tube (7); the hanging sealing mechanism (25) comprises a metal slip (2) and a sealing cylinder (3) which are fixed on the outer surface of the expansion hanging cylinder (1), wherein the metal slip (2) consists of a plurality of slip blocks (201) which are circumferentially arranged, and a circulating channel (205) is preset between every two adjacent slip blocks (201); the expansion mechanism (26) comprises an expansion mandrel (9) and a lower expansion cone (5), the expansion mechanism (26) is preset in an expansion starter (22) of the expansion suspension cylinder (1), the expansion mandrel (9) and the lower expansion cone (5) are of an integrated hollow structure or of a combined sleeved hollow structure, and the outer surface of the lower expansion cone (5) is provided with an upward expansion cone surface; The upper part of the expansion mandrel (9) is fixedly connected with the central tube (7); the back-off mechanism (27) is positioned at the lower part of the expansion mechanism (26) and comprises a hollow rubber plug (18), a bearing mandrel (10), a bearing (11), a spring sleeve (12), a spring (13), a back-off joint (14) and a variable-buckle joint (15); the bearing mandrel (10) is provided with a back-off joint (14), the back-off joint (14) is provided with a back-off thread, and the back-off joint (14) is connected with the variable-speed joint (15) in a matching way through the back-off thread; the back-off joint (14) and the bearing mandrel (10) form circumferential synchronous rotation and circumferential sliding fit; a spring (13) and a spring sleeve (12) are arranged on a bearing mandrel (10) at the upper part of the back-off joint (14), the spring (13) is positioned between the bearing mandrel (10) and the spring sleeve (12), the upper part of the bearing mandrel (10) is fixedly connected with an expansion mandrel (9), and a bearing (11) is arranged between the spring sleeve (12) on the bearing mandrel (10) and the expansion mandrel (9); the hollow rubber plug (18) is connected to the bottom of the bearing mandrel (10) through a pin; the expansion hanging cylinder (1) and the variable buckle joint (15) are sequentially and fixedly connected from top to bottom to form an outer tubular column; the hydraulic cylinder mechanism (6), the central tube (7), the expansion mandrel (9), the bearing mandrel (10) and the hollow rubber plug (18) are sequentially and fixedly connected from top to bottom to form an inner tubular column; The back-off mechanism (27) further comprises a rubber plug rod (17), the hollow rubber plug (18) is fixedly arranged at the bottom of the rubber plug rod (17) through a pin, the rubber plug rod (17) is connected with the bearing mandrel (10), and the hollow rubber plug (18) is preset in a tail pipe (16) connected with the expansion hanger; the hanging sealing mechanism (25) further comprises a fixing nipple (8), and the expansion mandrel (9) and the lower expansion cone (5) are fixedly connected with the central tube (7) above through the fixing nipple (8).

2. The dual suspension dual seal high temperature resistant expansion hanger of claim 1, wherein: the sealing cylinder (3) is formed by one or more of a rubber cylinder (301), a rubber cylinder (301) -trapezoid metal ring (302) or a rubber cylinder (301) -zigzag metal ring (303) in a matched mode.

3. The dual suspension dual seal high temperature resistant expansion hanger of claim 2, wherein: the rubber cylinder (301) adopts high-temperature resistant fluororubber, and the outer surface of the expansion suspension cylinder (1) at the position of the rubber cylinder (301) is provided with a metal protrusion in limit fit with the rubber cylinder (301).

4. A dual suspension dual seal high temperature expansion hanger according to claim 3 and wherein: the trapezoid metal ring (302) is of an outer wide and inner narrow structure, the trapezoid metal ring (302) and the zigzag metal ring (303) are made of soft metal materials, and the outer diameter of the trapezoid metal ring is slightly smaller than that of the rubber cylinder (301).

5. The dual suspension dual seal high temperature expansion hanger of any of claims 1-4, wherein: slip teeth (202) are machined on the slip blocks (201), and adjacent slip blocks (201) are fixed through connecting ribs (203) and fixing rings (204); the connecting ribs (203) are of open non-closed-loop structures, and the outer diameter of the connecting ribs (203) is smaller than that of the slip segments (201); the outer diameter of the fixed ring (204) is slightly smaller than the outer diameter of the slip segments (201).

6. The dual suspension dual seal high temperature resistant expansion hanger of claim 5, wherein: the adjacent slip segments (201) are fixed through connecting ribs (203) at the lower part and the middle part, and the upper parts of the slip segments (201) are fixed through fixing rings (204).