CN112302545A

CN112302545A - Downhole small tubing device and tubing string

Info

Publication number: CN112302545A
Application number: CN201910688105.3A
Authority: CN
Inventors: 雷炜; 姚麟昱; 赵华; 许剑; 滕汶江; 杜洋; 付先惠; 曾兴平
Original assignee: China Petroleum and Chemical Corp; Sinopec Southwest Oil and Gas Co
Current assignee: China Petroleum and Chemical Corp; Sinopec Southwest Oil and Gas Co
Priority date: 2019-07-29
Filing date: 2019-07-29
Publication date: 2021-02-02
Anticipated expiration: 2039-07-29
Also published as: CN112302545B

Abstract

The invention provides a downhole small oil pipe device and a tubular column, wherein the downhole small oil pipe device comprises a feeding mandrel, a central cylinder which can be selectively arranged at the lower end of the feeding mandrel, a first clamping hanger which is sleeved outside the feeding mandrel, a setting assembly which is sleeved outside the central cylinder and is positioned at the lower end of the first clamping hanger, and a small oil pipe which is arranged at the lower end of the central cylinder in a communicating manner. And the second clamping and hanging piece is cylindrical, so that the inner drift diameter of the tubular column and later-stage operation are not influenced.

Description

Downhole small tubing device and tubing string

Technical Field

The invention relates to the technical field of downhole tools of oil and gas wells, in particular to a downhole small oil pipe device and a pipe column.

Background

For gas wells, especially low-pressure low-yield gas wells affected by liquid accumulation, the smaller the inner diameter of a production oil pipe is, the faster the gas flow rate is, the better the liquid carrying effect is, and the more stable the production is. Also, as a result, in gas well drainage gas production, the smaller the tubing size the better. However, the gas production string must first meet the requirements of fracturing construction, and for large scale fracturing, the larger the tubing size the better. In order to improve the yield, the coiled tubing replacement process is adopted to meet the drainage requirement of the gas well at the later stage of production.

In the prior art, a mode of putting a coiled tubing into a fracturing string to be used as a production string is often adopted for production so as to reduce the flow area of the production string. The process does not need well killing operation, has small damage to the gas well and is widely applied to the production of the gas well. However, in the construction, the coiled tubing matched with the well depth length needs to be put in for production, so that the material consumption of the tubing is large, and the production cost is high.

Disclosure of Invention

The invention provides a downhole small oil pipe device and a pipe column aiming at part or all of the technical problems in the prior art. The underground small oil pipe device is constructed in a rear-mounted mode, namely the second clamping and hanging piece matched with the underground small oil pipe device is firstly put into a shaft, and when water drainage and gas production are needed, the underground small oil pipe device is put into the shaft so that the coiled tubing is suspended and transferred from a wellhead to the underground, and the using amount of the coiled tubing can be reduced. And the second clamping and hanging piece is cylindrical, so that the inner drift diameter of the tubular column and later-stage operation are not influenced.

According to a first aspect of the present invention, there is provided a downhole small oil pipe device comprising:

the feeding and releasing core shaft is arranged on the upper portion of the feeding and releasing core shaft,

a central cylinder which can be selectively arranged at the lower end of the feeding and releasing mandrel,

a first clamping and hanging piece sleeved on the outer side of the feeding core shaft,

a setting component sleeved outside the central cylinder and positioned at the lower end of the first clamping and hanging piece,

the small oil pipe is arranged at the lower end of the central cylinder in a communicating manner.

In one embodiment, the setting assembly has:

the outer cylinder is sleeved outside the central cylinder, the upper end of the outer cylinder extends into the inner cavity of the first clamping and hanging piece and is fixedly connected with the inner cavity,

the rubber sleeve is sleeved on the outer side of the outer cylinder and located at the lower end of the first clamping and hanging piece, the rubber sleeve comprises a fixed end fixed relative to the outer cylinder and a free end extending out from the fixed end along the axial direction, and an idle space is formed between the rubber sleeve and the outer cylinder at intervals between the fixed end and the free end; and

the lower end of the inserting body is fixedly sleeved on the outer wall of the central cylinder, the upper end of the inserting body extends into the free space, and the central cylinder drives the inserting body to push the rubber cylinder to move radially in the upward movement process of the inserting body.

In one embodiment, the insert forms an inclined outer surface between the upper and lower ends towards the glue cartridge.

In one embodiment, a plurality of rib-shaped metal contact pieces are arranged at intervals on one side of the rubber tube facing the empty space, and when the insertion body is inserted into the empty space, the metal contact pieces are engaged with the outer surface of the insertion body.

In one embodiment, a first sealing ring is arranged between the outer cylinder and the rubber cylinder,

and/or a second sealing ring is arranged between the outer cylinder and the central cylinder.

In one embodiment, a clamp spring is arranged on the outer wall of the central cylinder, and a plurality of clamp spring grooves capable of being matched with the clamp spring are arranged on the inner wall of the outer cylinder at intervals.

In one embodiment, the feeding and discharging mandrel is connected with the central cylinder through a shear pin,

and/or a limiting ring for preventing the central cylinder from moving upwards is arranged on the inner wall of the outer sleeve.

In one embodiment, the first snap hook has a first snap hook body, circumferentially spaced resilient fingers extending axially upward from the first snap hook body, and a first snap portion protrudingly disposed on an outer peripheral wall of the resilient fingers.

In one embodiment, the ratio of the radial dimension to the axial dimension of the small oil pipe is from 1:2 to 1: 8.

According to a second aspect of the present invention, there is provided a tubular string comprising one or more second tubular latching members, at least one of which is capable of cooperating with a first latching member of a small downhole tubing assembly as described above.

Compared with the prior art, the underground small oil pipe device has the advantages that the underground small oil pipe device is provided with the small oil pipe, and the section size of the oil pipe for water drainage and gas production can be reduced after the underground small oil pipe device is lowered, so that a good water drainage and gas production effect is achieved. Meanwhile, the small oil pipe is limited at the position in the shaft through the matching of the first clamping hanging piece and the second clamping hanging piece which is put in advance, so that the hanging of the oil pipe is transferred to the underground, and the using amount of the coiled tubing is reduced. Moreover, the radial small oil pipe device is of a rear-mounted type, namely, in the construction process, a second clamping and hanging piece which can be matched with the radial small oil pipe device can be firstly put into a shaft, and the radial small oil pipe device is put into the underground small oil pipe device when water drainage and gas production are needed. And the second fastener which is put in first is cylindrical, and the inner drift diameter of the tubular column and the later-stage gas well operation are not influenced. In addition, the underground small oil pipe device is matched with a pipe column which is put in firstly through clamping and hanging connection, and is simple in structure and reliable in connection.

Drawings

Preferred embodiments of the present invention will be described in detail below with reference to the attached drawing figures, wherein:

FIG. 1 shows a schematic representation of a run-in condition of a downhole small tubing set according to an embodiment of the present invention;

FIG. 2 shows a schematic diagram of a rubber sleeve setting condition of a downhole small tubing assembly according to an embodiment of the present invention;

FIG. 3 shows a schematic representation of the salvage status of a downhole small tubing set in accordance with an embodiment of the present invention;

FIG. 4 shows a downhole small tubing set according to another embodiment of the present invention;

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.

FIG. 1 shows a downhole small tubing assembly 100 according to the present invention. As shown in fig. 1, the small oil pipe device 100 includes a delivery mandrel 1, a central cylinder 2, a small oil pipe 3, a first hanger 4, and a setting assembly. The feeding and releasing mandrel 1 is columnar and used for putting the small oil pipe device 100 into a specified position and then lifting the small oil pipe device. The central cylinder 2 is arranged at the lower end of the feeding and releasing mandrel 11 and mainly plays a role in supporting and overflowing. And, the central cylinder 2 can be selectively connected with the delivery mandrel 1, so that after the small oil pipe device 100 is delivered in place and the packing is completed, the delivery mandrel 1 can be disconnected from the central cylinder 2, and the delivery mandrel 1 can be lifted out of the wellbore. The first clamping hanger 4 is sleeved on the outer wall of the feeding mandrel 1 and is used for matching with a second clamping hanger 200 of a pipe column (only the second clamping hanger 200 part of the pipe column is shown in the figure), so that clamping is realized to limit the position of the underground small oil pipe device 100. The setting assembly is arranged on the outer side of the central cylinder and is positioned at the lower end of the first clamping and hanging piece 4 and used for plugging an annular space between the underground small oil pipe device 100 and a pipe column. And the small oil pipe 3 is arranged at the lower end of the central cylinder 2 in a communicating manner and is used for water drainage and gas production.

The invention also relates to a pipe string. As shown in fig. 1, the pipe string includes a second hanger 200. The second hooking member 200 has a cylindrical structure, and a second hooking portion 201 is formed on an inner wall thereof. During construction, the second hanger 200 is first lowered into the wellbore following the pipe string. One or more second hangers 200 may be provided on the string according to construction needs, so that a tool such as the small tubing device 100 may be run into the string to engage with the second hangers 200 during production of oil or gas. This also ensures that different tools are run at different times to match the second pendant 200 in the proper location downhole. This approach also ensures that multiple different or identical tools are run in at the same time to mate with the second pendant 200 at different locations.

Through a large number of tests, the difficulty of carrying liquid in the gas well mainly occurs in the production inclined well section. As long as the problem of liquid accumulation of the inclined well section of the gas well is solved, the gas well can normally carry liquid for production. Thus, the downhole small oil pipe device 100 and the second hanger 200 are designed. In the construction process, the second tubular hanger 200 is set on the pipe string and is first lowered into the wellbore along with the pipe string. After fracturing construction is completed, the small tubing device 100 is lowered into the interior of the tubing string according to the production management requirements of the oil and gas well. Then the small oil pipe 3 is positioned by the second clamping and hanging piece 201, and then the small oil pipe 3 can be arranged near the inclined shaft section in the shaft, so that the length size of the small oil pipe 3 is greatly reduced, and the production cost is reduced. In addition, this way the downhole small tubing set 100 does not affect other gas well operations, as well as the full bore of the tubing string. In addition, the underground small oil pipe device 100 is connected with the second clamping and hanging piece 200 in a clamping and hanging mode, so that the connection stability is guaranteed, and the requirement for well deviation is lowered. Furthermore, according to the present invention, a plurality of second hangers 200 may be provided on the pipe string, and the downhole small oil pipe device 100 may be fitted with the corresponding second hangers 200 at a later stage to improve the positioning position accuracy.

In one embodiment, the first clip member 4 includes a first clip member body 41, an elastic claw 42, and a first clip portion 43. The first fastener body 41 is cylindrical and is sleeved outside the feeding core shaft 1. The elastic claw 42 extends axially upward from the first catch member body 41. A plurality of elastic claws 42, for example, 6 are provided at intervals in the circumferential direction. The elastic claw 42 is fitted to the feeding and discharging mandrel 1 with a gap therebetween. The first catching portion 43 is provided on the outer peripheral wall of the elastic claw 42 and is configured as a radially protruding boss. Preferably, in order to increase the hooking stability, a plurality of, for example, two spaced first hooking portions 43 are provided in the axial direction. Correspondingly, the second hooking portion 201 is configured as a groove for mating with the first hooking portion 43. In the process of putting the downhole small oil pipe device 100 in, the first clamping and hanging part 43 is stressed to enable the elastic claw 42 to radially contract, so that the downhole small oil pipe device 100 is ensured to be smoothly put in. When the first hooking part 43 reaches the position of the second hooking part 201, under the action of the elasticity of the first hooking part 43, the elastic claw 42 radially expands, so that the first hooking part 43 enters the second hooking part 201 and completes hooking to fix the downhole small oil pipe device 100. The clamping and hanging structure is simple and easy to realize. In addition, due to the above structural features, the unique correspondence of the snap-fit of the first snap fastener 4 and the second snap fastener 200 can be realized by changing the number, position, shape, size, and the like of the first snap fastener 43 and the corresponding second snap fastener 201. Therefore, a plurality of second clamping hangers 200 with second clamping hanging parts 201 of different structures or numbers can be put into the shaft, and in the later construction process, the first clamping hanger 4 matched with the second clamping hanger 200 in a proper position can be selected to be put into a pipe column so as to carry different gas production tools.

As shown in fig. 1, the setting assembly has an outer cylinder 5, a glue cylinder 6 and an insert 7. The lower end of the outer cylinder 5 is sleeved on the outer side of the central cylinder 2, and the upper end of the outer cylinder extends into the inner cavity of the first clamping hanging piece 4 and is fixedly connected with the first clamping hanging piece 4. The rubber sleeve 6 has certain deformability and is used for sealing off an annular space between the small oil pipe device 100 and the second clamping hanging piece 200. The upper end of the rubber cylinder 6 is a fixed end fixedly connected with the first clamping and hanging piece 4, and the lower end extends downwards along the axial direction and is a free end. The upper end of the rubber sleeve 6 is arranged on the first clamping and hanging piece 4 through a rubber sleeve fixing part 8. For example, a female screw is provided on the cartridge holder 8, and a corresponding male screw is provided on the first hooking member 4 for connection. The arrangement of the internal and external threads may be reversed as desired. Between the upper end and the lower end of the packing drum 6, the packing drum 6 is spaced apart from the outer cylinder 5 to form an empty space 63. The lower end of the insertion body 7 is fixedly fitted on the outer wall of the central cylinder 2, while the upper end extends axially upward to overlap the outer wall of the outer cylinder 5 while being inserted into the empty space 63. The inserting body 7 can move axially relative to the rubber tube 6 under the driving of the central tube 2, and can be inserted into the free space 63 and push the rubber tube 6 radially outwards in the relative upward movement process of the inserting body 7, so that the setting of the setting assembly is completed.

The glue cartridge 6 may have a substantially trapezoidal or triangular cross-section, with a smaller cross-section at the lower end and a larger cross-section at the upper end. Thereby, the packing tube 6 and the outer tube 5 can be spaced apart in the radial direction, so that a certain empty space 63 can be formed between the packing tube 6 and the outer tube 5.

An inclined outer surface 71 is provided between the upper end of the insert towards the glue tube 6 and the lower end away from the glue tube 6. That is, the upper end of the insert body 7 is configured as a wedge shape having a radial dimension gradually increasing in the upper-to-lower direction to be inserted into the empty space 63 to urge the rubber cartridge 6 to move radially during following the upward movement of the center cartridge 2.

In one embodiment, a metal contact 64 is provided in the rubber cylinder 5 on the side facing the empty space 63, so that the insertion body 7 engages with the surface of the metal contact 64 after being inserted into the empty space 63, as shown in fig. 4. Preferably, the metal contacts 64 are multiple and spaced apart circumferentially. That is, the metal base member is in the form of a rib, and is bonded to the rubber tube 5 by a vulcanization process. During the upward movement of the insertion body 7 relative to the rubber cylinder 5, the rubber cylinder 5 is deformed and the lower end of the metal contact piece 64 is opened. Conversely, during the downward movement of the insertion body 7 with respect to the glue cartridge 5, the glue cartridge 5 is retracted and the lower end of the metal contact 64 is closed. The friction force between the inserting body 7 and the rubber cylinder 5 is reduced by arranging the metal contact piece 64, so that the sealing performance is ensured, meanwhile, the service life of the rubber cylinder 5 can be prolonged, and the sealing capability of the rubber cylinder is improved.

In one embodiment, a first sealing ring 9 is provided between the outer cylinder 5 and the glue cylinder 6. A second seal ring 10 is provided between the outer cylinder 5 and the central cylinder 2. Through setting up above-mentioned two

sealing washer

9, 10 can prevent that the fluid from further moving up through corresponding position to make the fluid all move up through little oil pipe 3, thereby guaranteed drainage gas production effect.

A clamp spring 21 is arranged on the outer wall of the central cylinder 2. Meanwhile, a plurality of snap spring grooves 51 capable of being matched with the snap springs 21 are arranged on the inner wall of the outer cylinder 5 at intervals, for example, the number of the snap spring grooves 51 is two. During the axial displacement of the central cylinder 2 relative to the outer cylinder 5, the snap springs 21 are located in different snap spring grooves 51. Specifically, during the running in of the small oil pipe device 100, the snap spring 21 is in the snap spring groove 51 in the lower end, so that the insertion body 7 and the rubber sleeve 6 are in the initial overlapping position. After the small oil pipe device 100 is lowered, the central cylinder 2 is lifted upwards (which is realized by lifting the releasing mandrel 1), at this time, the first clamping hanger 4 is clamped at the second clamping hanger 200, the outer cylinder 5 is not moved, so that the central cylinder 2 moves upwards relative to the outer cylinder 5, and the clamping spring 21 moves upwards along with the central cylinder 2 and enters the clamping spring groove 51 at the upper end. At the same time, the central cylinder 2 drives the insertion body 7 to move upwards, thereby actuating the rubber cylinder 6 to expand radially. When the setting is released, the central cylinder 2 is pressed downwards to drive the inserting body 7 to move downwards relative to the rubber cylinder and the outer cylinder 5 together, so that the setting of the rubber cylinder 6 is released. That is, the position of the insert 7 is defined by the engagement of the circlip 21 with the circlip groove 51, thereby ensuring the setting or the unsetting of the glue cartridge 6. A stop ring 52 is provided in the inner cavity of the outer cylinder 5 for limiting the center cylinder 2 from moving further upward. The limiting ring 52 is annular and is fixedly arranged on the inner wall of the outer cylinder 5, and in the lifting process of the delivery mandrel 1, after the snap spring 21 is matched with the snap spring groove 51 at the upper end, the upper end surface of the central cylinder 2 abuts against the limiting ring 52, so that the central cylinder 2 is prevented from continuously moving upwards when the delivery mandrel 1 is lifted.

In one embodiment, as shown in FIG. 1, the delivery mandrel 1 has a shaft-like mandrel body 11 and a delivery head 12. Wherein, the feeding head 12 is arranged at the upper end of the mandrel main body 11, the radial section area of the feeding head is larger than that of the mandrel main body 11, and the feeding head is used for being fixedly connected with a feeding tool. For example, threads may be provided on the outer wall of the delivery head 12 to enable connection with a delivery tool. The mandrel main body 11 extends vertically, and the lower end of the mandrel main body is connected with the first clamping hanging piece 4 through a shearing pin 101, so that the feeding mandrel 1 can be selectively connected with the first clamping hanging piece 4. After the small tubing set 100 is brought to a predetermined position and the packing cartridge 6 is actuated to set, the payout mandrel 1 is lifted up and the shear pins 101 are sheared to lift out the payout mandrel 1 as shown in FIG. 2.

A ratchet seat 44 is fitted on an inner wall of the first hooking member body 41. The ratchet socket 44 can mate with the ratchet 303 of the fishing device 300 to lift the first snap hanger 4 out of the wellbore. That is to say, when water drainage and gas production are not needed, the small oil pipe device 100 can be lifted out of the shaft, so that the full drift diameter is realized, and the smooth implementation of the production and transportation process procedures such as water drainage and gas production at the later stage is facilitated.

An upwardly facing first inclined surface 45 is provided between the upper end surface and the outer side surface of the elastic claw 42. The first ramp 45 is used to mate with a fishing device during fishing (discussed in detail below).

The invention also relates to a fishing device 300. As shown in fig. 3, the fishing device 300 includes a fishing head 301 and a fishing mandrel 302. The fishing head 301 is adapted to be connected to an external structure such that the external structure (e.g., coiled tubing) can be lowered into a predetermined position in the wellbore with the fishing apparatus 300. The fishing mandrel 302 is fixedly connected with the fishing head 301, and meanwhile, the fishing mandrel 302 can also be matched with the first clamping piece 4 positioned in the second clamping piece 200 in a locking manner. The fishing device 300 is lifted up to lift the first bail 4 out of the wellbore.

Specifically, a ratchet 303 is provided on the outer wall of the lower end of the fishing mandrel 302. In order to ensure the smooth matching and connection stability with the ratchet seat 44, a plurality of ratchets 303 are arranged on the outer wall of the lower end of the fishing mandrel 302. A plurality of ratchet teeth 303 are arranged side by side along the direction of extension of the fishing mandrel 302.

The lower end surface of the fishing head 301 is provided with a mounting groove 304. The upper end of the fishing mandrel 302 can extend into the mounting slot 304, such as by a threaded connection. The side walls of the mounting groove 304 are in clearance fit with the outer wall of the fishing mandrel 302. A second slope 305 is provided between the lower end surface of the mounting groove 304 and the inner wall surface. During the process of descending the fishing device 300, the second inclined surface 305 is inserted into an annular space formed by the first inclined surface 45 and the second clamping hanging piece 200, and along with the continuous descending of the fishing device 300, the second inclined surface 305 applies force to the first inclined surface 45 and actuates the elastic claw 42 to radially contract, so that the upper end of the elastic claw 42 is gathered in the installation groove 304, and meanwhile, the first clamping hanging part 43 is separated from the second clamping hanging part 201 to release clamping limitation.

The small oil pipe 3 in the present application means that the flow area is reduced after the small oil pipe device 100 is installed, so as to perform water drainage and gas production. But no limitation is made to the specific cross-sectional size of the small oil pipe 3. In engineering practice, the small oil pipe 3 with different cross-sectional areas can be selected according to different gas wells. To ensure good water and gas production, the ratio of the radial dimension to the axial dimension of the small oil pipe 3 is preferably 1:2 to 1:8, for example, 1: 5.

The operation of the small tubing assembly 100 and associated string and fishing assembly 300 is discussed in detail below with respect to fig. 1-4.

First, the second clip 200 is set on the pipe string, and then the pipe string is run into the wellbore. After the gas well is put in place, the second clamping and hanging piece 200 is cylindrical, so that the operation of other gas wells is not influenced.

When water drainage and gas production are required, the small oil pipe device 100 is lowered into the pipe string by a running tool such as a coiled tubing. During the run in of the small oil pipe device 100, the resilient fingers 42 radially contract and do not interfere with the run in of the small oil pipe device 100. At the same time, the circlip 21 is in the circlip groove 51 at the lower end, and the insert 7 is in the initial position without moving the glue cartridge 6 radially. When the first hooking portion 43 reaches the position of the second hooking portion 201, under the action of its own elasticity, the elastic claw 42 radially expands, so that the first hooking portion 43 and the second hooking portion 201 complete hooking, so as to fix the small oil pipe device 100, as shown in fig. 1. In the process, the circlip 21 is always in the lower circlip groove 51 to define the relative position of the insert 7 and the glue cartridge 6, preventing the glue cartridge 6 from setting in advance.

Then, the feeding tool is lifted up, the feeding and releasing mandrel 1 drives the central cylinder 2 to move upwards (because the feeding and releasing mandrel and the central cylinder are connected through the shearing pin 101), the first clamping and hanging piece 4 cannot move because the first clamping and hanging piece 4 is arranged at the second clamping and hanging piece 200, and the rubber cylinder 6 and the outer cylinder 5 cannot move because the rubber cylinder 6 and the outer cylinder 5 are fixedly connected with the first clamping and hanging piece 4. Thus, the above-mentioned pulling on the one hand causes the insert 7 to move upwards with respect to the cartridge 6, thus actuating the radial expansion of the cartridge 6 to effect setting; on the other hand, the snap spring 21 moves upwards to enter the snap spring groove 51 at the upper end, and the snap spring 21 and the snap spring groove 51 which are matched with each other limit the position of the inserting body 7, so that the setting stability of the rubber cylinder 6 is ensured. At this time, the upper end surface of the center cylinder 2 abuts against the stopper ring 52. And (3) continuing to lift the delivery mandrel 1, since the central cylinder 2 is limited by the limiting ring 52 and cannot move upwards continuously, the shearing pin 101 is sheared, the fixation between the central cylinder 2 and the delivery mandrel 1 is released, and the delivery mandrel 1 is lifted out of the shaft, as shown in fig. 2. At this time, the fluid enters the central cylinder 2 through the small oil pipe 3, and the water drainage and gas production effects are generated.

When water drainage and gas production are not needed, the fishing device 300 can be put in, and the small oil pipe device 100 is fished out to realize full drift diameter. Specifically, the fishing device 300 is lowered, and the fishing device 300 is pressed down. In the downward moving process of the fishing device 300, the fishing device 300 is abutted against the central cylinder 2, in the process of pressing the fishing device 300 downward, the central cylinder 2 moves downward along with the fishing device 300, so that the clamp spring 21 is separated from the clamp spring groove 51 at the upper end and continuously moves downward to enter the clamp spring groove 51 at the lower end, at the moment, the inserting body 7 moves downward relative to the rubber cylinder 6, and the rubber cylinder 7 is unsealed. During the downward movement of the fishing device 300, the ratchet 303 cooperates with the ratchet seat 44 of the small tubing set 100 to form a locking structure. Meanwhile, the second inclined surface 305 applies force to the first inclined surface 45, and the elastic claw 42 is actuated to contract radially, so that the clamping limitation of the first clamping hanging piece 4 and the second clamping hanging piece 200 is released. At this point, the remaining small tubing set 100 may be lifted out of the wellbore by lifting the fishing apparatus 300.

In the present application, the terms "upper" and "lower" are used with reference to the actual operating orientation of the downhole small oil pipe apparatus 100.

The above is only a preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily make changes or variations within the technical scope of the present invention disclosed, and such changes or variations should be covered within the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. A downhole small tubing assembly, comprising:

2. The downhole small tubing assembly of claim 1, wherein the setting assembly has:

3. The downhole small tubing assembly of claim 2, wherein the insert body forms an inclined outer surface between the upper and lower ends toward the glue cartridge.

4. The downhole small oil pipe assembly of claim 3 wherein a plurality of rib-like metal contacts are spaced on a side of the rubber sleeve facing the void space, the metal contacts engaging an outer surface of the insert body when the insert body is inserted into the void space.

5. The downhole small oil pipe device according to any one of claims 2 to 4, wherein a first seal ring is provided between the outer cylinder and the rubber cylinder,

6. The downhole small oil pipe device according to any one of claims 2 to 5, wherein a snap spring is arranged on the outer wall of the central cylinder, and a plurality of snap spring grooves capable of being matched with the snap spring are arranged on the inner wall of the outer cylinder at intervals.

7. The downhole small oil pipe device according to any one of claims 2 to 6, wherein the payout mandrel and the central cylinder are connected by a shear pin,

8. The downhole small tubing assembly according to any one of claims 1 to 7, wherein the first catch member has a first catch member body, circumferentially spaced resilient claws extending axially upward from the first catch member body, and first catch portions protrudingly provided on an outer peripheral wall of the resilient claws.

9. The downhole small oil pipe device according to any one of claims 1 to 8, wherein the ratio of the radial dimension to the axial dimension of the small oil pipe is 1:2-1: 8.

10. A pipe string comprising one or more second tubular latching members, at least one of said second latching members being engageable with a first latching member of a small downhole tubing assembly according to any one of claims 1 to 9.