阅读说明：本技术 一种同径双层连续油管连接装置 (Same-diameter double-layer continuous oil pipe connecting device ) 是由 唐洋 杨鑫 孙鹏 姚佳鑫 何胤 吴杰 刘祥 敬鑫 于 2019-11-21 设计创作，主要内容包括：本发明公开了一种同径双层连续油管连接装置,该装置用于水合物开采中井下两口径相同的双层连续油管之间的连接。两段内外同径双层连续油管的内层管、外层管均为光管,卡瓦通过卡瓦压紧套的挤压实现卡瓦与外层连续油管的外壁咬合,卡瓦压紧套通过螺纹与连续油管接头体外层连接,内层连续油管接头体通过内卡瓦连接器与连续油管的内层管进行连接；连续油管接头体上设置有四个环形流道用于连续油管的外层管与内层管之间的流体通过；连续油管接头体与连续油管的外层管、芯轴连接处均设置有O环形密封圈。本发明可实现两段内外同径双层连续油管连接,保证该连接处可抗拉、抗扭矩和承内压,且具有结构紧凑、连接安全、安装简单等特点。(The invention discloses a connecting device for double-layer coiled tubing with the same diameter, which is used for connecting two underground double-layer coiled tubing with the same diameter in hydrate exploitation. The inner layer pipe and the outer layer pipe of the two sections of the inner and outer same-diameter double-layer coiled tubing are light pipes, the slips are meshed with the outer wall of the outer layer coiled tubing through the extrusion of the slip pressing sleeve, the slip pressing sleeve is connected with the outer layer of the coiled tubing connector body through threads, and the inner layer coiled tubing connector body is connected with the inner layer pipe of the coiled tubing through the inner slip connector; the coiled tubing connector body is provided with four annular flow passages for fluid between an outer layer tube and an inner layer tube of the coiled tubing to pass through; o-ring-shaped sealing rings are arranged at the joints of the coiled tubing connector body, the outer-layer tube and the mandrel of the coiled tubing. The invention can realize the connection of two sections of inner and outer double-layer coiled pipes with the same diameter, ensures that the connection part can resist tension, torque and internal pressure, and has the characteristics of compact structure, safe connection, simple installation and the like.)

1. The same-diameter double-layer coiled tubing connecting device is characterized by comprising a slip pressing sleeve (3), an outer slip (4), a coiled tubing connector body (5) and an inner slip connector,

the slip pressing sleeve (3) and the outer slip (4) are sequentially sleeved on an outer layer pipe (1) of the double-layer coiled oil pipe, a conical space for accommodating the outer slip (4) is formed in the slip pressing sleeve (3), and the outer slip (4) is located in the slip pressing sleeve (2);

the outer layer of the coiled tubing connector body (5) is sleeved on the outer layer tube (1) of the double-layer coiled tubing and is in threaded connection with the slip pressing sleeve (3), and when the end part of the coiled tubing connector body (5) tightly pushes the outer slip (4), the end part of the outer layer tube (1) of the double-layer coiled tubing is pushed against a limiting step (501) formed on the inner side of the coiled tubing connector body (5);

the inner slip connector comprises a mandrel (7), an inner slip (8), a sealing head (9) and a push nut (10), wherein during installation, the inner slip (8), the sealing head (9) and the push nut (10) are sequentially sleeved on the mandrel (7), the push nut (10) is connected with the mandrel (7) through threads, the push nut (10) on the mandrel (7) is screwed up to pre-tighten the inner slip (8), then the mandrel (7) is connected with the inner layer of the coiled tubing joint body (5) through threads, and the installation of the inner slip connector and the coiled tubing joint body (5) is completed; and finally, inserting the inner slip connector arranged on the coiled tubing joint body (5) into the inner pipe (2) of the double-layer coiled tubing.

2. The same-diameter double-layer coiled tubing connection device as claimed in claim 1, wherein the inner wall of the outer slip (4) is of a cylindrical structure and is provided with sawtooth-shaped slip teeth (402), and the inner layer of the slip pressing sleeve (3) forms a wedge-shaped surface (301); when the slip pressing sleeve (3) and the coiled tubing connector body (5) are close to each other in the screwing-in matching of threads, the outer slip (4) located in the slip pressing sleeve (3) moves towards the wedge-shaped surface (301) inside the slip pressing sleeve under the thrust action of the coiled tubing connector body (5), the wedge-shaped surface (401) of the outer slip is subjected to the radial acting force generated after the extrusion action of the wedge-shaped surface (301) inside the slip pressing sleeve, so that the sawtooth-shaped teeth on the inner wall of the outer slip (4) interact with the outer-layer pipe (1) of the coiled tubing, and finally the outer slip (4) is wedged into the pipe wall to tightly hold the outer-layer pipe (1) of the double-layer coiled tubing, so that the connection between the coiled tubing connector body (5) and the outer-layer pipe (1) of the.

3. The same-diameter double-layer coiled tubing connecting device as claimed in claim 1, wherein the lower end of the inner slip (8) is annular, slip teeth (801) are arranged on the outer wall of the upper end of the inner slip (8), and when the inner slip connector is inserted into the inner pipe (2) of the coiled tubing, under the action of axial force, the inner wall of the inner pipe (2) of the coiled tubing is bitten by radial clamping force generated under the attaching action of the inner slip conical surface (802) and the mandrel conical surface (701), so that the connection between the coiled tubing connector body (5) and the inner pipe (2) of the coiled tubing is realized.

4. The dual coiled tubing connection of the same diameter as in claim 1, wherein the coiled tubing joint body (5) is provided with four annular flow passages (504), the flow passages (504) being used for fluid passage between the outer tube (1) and the inner tube (2) of the coiled tubing.

5. The same-diameter double-layer coiled tubing connecting device as claimed in claim 1, wherein the outer pipe (1) and the inner pipe (2) of the coiled tubing are equal in length, and when the end of the coiled tubing connector body (5) is tightly pressed against the outer slip (4), the end of the inner pipe (2) of the double-layer coiled tubing is also pressed against a limiting step (502) formed on the inner side of the coiled tubing connector body (5).

6. The same-diameter double-layer coiled tubing connecting device as claimed in claim 1, wherein an O-ring seal ring (6) is arranged at the joint of the coiled tubing connector body (5) and the outer layer tube (1) of the coiled tubing, and O-ring seal rings (11) and (12) are respectively arranged at the contact parts of the mandrel (7) and the coiled tubing connector body (5) and the inner layer tube (2) of the coiled tubing.

Technical Field

The invention belongs to the technical field of natural gas hydrate exploitation, and particularly relates to a same-diameter double-layer coiled tubing connecting device.

Background

The natural gas hydrate is a novel clean, high-quality and efficient energy source found in the world, is a research hotspot of the oil and gas industry, and is an indispensable important material in the future energy strategy. The global reserves of natural gas hydrates are enormous, but the current development is not mature, and particularly in the ocean, the traditional exploitation methods comprise a depressurization method, a heat injection method, a chemical inhibitor method and C0₂And the replacement mining methods and the like only perform short-term trial mining technical demonstration verification on the natural gas hydrates of the polar sandstone reservoir and the sea area sandstone reservoir, and the safety cannot be completely ensured. Therefore, a completely new exploitation mode needs to be considered for the development of natural gas hydrate stored in deep water shallow layers within 300 meters of the surface layer of the sea bottom. The Zhou defends to put forward a deep-water shallow-layer natural gas hydrate solid fluidization exploitation technology according to the world sea area hydrate sampling and the China sea area hydrate sampling condition, reduces the environmental risk possibly brought by shallow hydrate decomposition, and achieves the purpose of green controllable exploitation.

In the solid fluidized exploitation of the shallow hydrate on the seabed, a double-layer coiled tubing is required to replace a single-layer tube for conventional oil gas exploitation, so that the effects of downwards conveying high-pressure seawater from an outer tube and upwards conveying natural gas hydrate from an inner tube are achieved. In the drilling and excavating processes of hydrates, the connection length of the double-layer coiled tubing is often not enough due to the fact that the measured distance does not accord with the actual working condition or due to other reasons, at the moment, a connecting device is needed to connect the double-layer coiled tubing with the same caliber with air to meet the use requirement, in the existing double-layer coiled tubing connector body, a device is not provided to enable the double-layer coiled tubing with the same caliber to be reliably connected, in addition, in the operation process, the double-layer coiled tubing always bears a certain axial force, and therefore the connection part of the device needs to be ensured to have high stability and tensile strength. Therefore, in order to realize the solid-state fluidized exploitation of the deep-water shallow-layer natural gas hydrate based on the double-layer coiled tubing technology, the invention of the same-diameter double-layer coiled tubing connecting device is required to ensure that two double-layer coiled tubing with the same diameter can be reliably connected, so that the stable connection at the light pipe of the double-layer coiled tubing is enhanced and the tensile strength at the connecting part is improved.

Disclosure of Invention

The invention aims to: the connecting device for the same-diameter double-layer coiled tubing used for solid fluidized exploitation of the natural gas hydrate solves the problem of butt joint of the same-diameter double-layer coiled tubing of which the inner layer tubing and the outer layer tubing are both polished rods, and solves the problem of connection between the coiled tubing connecting device and the two layers of double-layer coiled tubing which are both light tubes.

In order to achieve the purpose, the technical scheme adopted by the invention is as follows:

a same-diameter double-layer coiled tubing connecting device comprises a slip pressing sleeve, an outer slip, a coiled tubing connector body and an inner slip connector.

The outer slip pressing sleeve and the outer slip are sequentially sleeved on an outer layer pipe of the double-layer continuous oil pipe, a conical space for accommodating the outer slip is formed in the slip pressing sleeve, and the outer slip is located in the slip pressing sleeve.

The outer layer of the coiled tubing connector body is sleeved on the outer layer tube of the double-layer coiled tubing and is in threaded connection with the slip pressing sleeve, and when the end portion of the coiled tubing connector body tightly pushes the outer slip, the end portion of the outer layer tube of the double-layer coiled tubing pushes a limiting step formed on the inner side of the coiled tubing connector body.

The inner slip connector comprises a mandrel, an inner slip, a sealing head and a push nut, wherein during installation, the inner slip, the sealing head and the push nut are sequentially sleeved on the mandrel, the push nut is connected with the mandrel through threads, the push nut on the mandrel is screwed tightly to pre-tighten the inner slip, then the mandrel is connected with the inner layer of the continuous oil pipe joint body through threads, and the installation of the inner slip connector and the continuous oil pipe joint body is completed; and finally, inserting the inner slip connector arranged on the coiled tubing joint body into an inner pipe of the double-layer coiled tubing.

The inner wall of the outer slip is of a cylindrical structure and is provided with saw-tooth-shaped slip teeth, and the inner layer of the slip pressing sleeve forms a wedge-shaped surface; when the slip pressing sleeve and the continuous oil pipe joint body are screwed in and close to each other in a thread mode, the outer slip moves towards the wedge-shaped surface inside the slip pressing sleeve under the thrust action of the continuous oil pipe joint body in the slip pressing sleeve, the wedge-shaped surface of the outer slip generates radial acting force after being extruded by the wedge-shaped surface inside the slip pressing sleeve, the sawtooth teeth on the inner wall of the outer slip interact with the outer pipe of the continuous oil pipe, and finally the outer slip is wedged into the pipe wall to tightly hold the outer pipe of the double-layer continuous oil pipe, so that the connection between the continuous oil pipe joint body and the outer pipe of the continuous oil pipe is achieved.

The lower extreme of interior slips is the ring shape, and interior slips upper end outer wall is provided with the slips tooth, and after interior slips connector inserted coiled tubing's inlayer pipe, under the effect of axial force, the radial clamping force that produces under the laminating effect of interior slips conical surface and dabber conical surface bites the inner wall of coiled tubing inlayer pipe, realizes being connected of coiled tubing joint body and coiled tubing's inlayer pipe (2).

The coiled tubing connector body is provided with four annular flow passages, and the flow passages are used for fluid between an outer layer pipe and an inner layer pipe of the coiled tubing to pass through.

The outer layer pipe and the inner layer pipe of the coiled tubing are equal in length, and when the end of the coiled tubing connector body abuts against the outer slip, the end of the inner layer pipe of the double-layer coiled tubing also abuts against a limiting step formed on the inner side of the coiled tubing connector body.

And the joints of the coiled tubing connector body and the outer layer tube of the coiled tubing are provided with O-shaped sealing rings, and the contact parts of the mandrel and the coiled tubing connector body as well as the inner layer tube of the coiled tubing are provided with O-shaped sealing rings.

In summary, due to the adoption of the technical scheme, the invention has the beneficial effects that:

(1) the same-diameter connection can be realized, and two double-layer coiled pipes with the same diameter are communicated; (2) the same-diameter connecting device of the double-layer coiled tubing can bear certain torque and the connecting part can bear certain internal pressure; (3) the connection between the inner layer pipe and the outer layer pipe of the coiled tubing and the coiled tubing joint body adopts the slip to be matched with the coiled tubing joint body to be occluded on the light pipe, and the coiled tubing joint has the characteristics of high tensile strength and high stability; (4) the device has compact structure, safe connection and simple installation.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present invention and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained according to the drawings without inventive efforts.

FIG. 1 is a half sectional view of a double-layer coiled tubing same-diameter connecting device;

FIG. 2 is a block diagram of a slip hold down sleeve;

FIG. 3 is a view showing the structure of an outer slip

FIG. 4 is a view of a coiled tubing joint body configuration;

FIG. 5 is a top isometric view of the coiled tubing joint body;

FIG. 6 is a view of the mandrel structure;

FIG. 7 is a view of the inner slip structure;

the labels in the figure are: 1-inner layer pipe, 2-outer layer pipe, 3-slip pressing sleeve, 4-outer slip, 5-coiled tubing connector body, 6-O type sealing ring, 7-mandrel, 8-inner slip, 9-sealing head, 10-pushing nut, 11-O type sealing ring, 12-O type sealing ring, 301-slip pressing sleeve inner wedge face, 401-outer slip wedge face, 402-zigzag tooth of outer slip, 501-limiting step of double-layer coiled tubing outer layer pipe in coiled tubing connector body, 502-limiting step of double-layer coiled tubing inner layer pipe in coiled tubing connector body, 503-annular flow channel, 504-limiting step of mandrel in coiled tubing connector body, 701-mandrel conical face, 702-mandrel end face, 801-inner slip tooth, 802-inner slip cone.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention. The components of embodiments of the present invention generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations.

Thus, the following detailed description of the embodiments of the present invention, presented in the figures, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments of the present invention without making any creative effort, shall fall within the protection scope of the present invention.

It is noted that relational terms such as "upper" and "lower," and the like, may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.

The features and characteristics of the present invention are described in further detail below with reference to the attached drawings and specific embodiments.