阅读说明：本技术 一种带有保温功能的水下天然气水合物井口装置 (Underwater natural gas hydrate wellhead device with heat preservation function ) 是由 刘丽娟 赵锦栋 罗飞 王地川 边培明 敬凤 于 2020-03-23 设计创作，主要内容包括：本发明属于储层钻井技术领域,尤其涉及一种带有保温功能的水下天然气水合物井口装置。其特征在于主要由外壳,接箍,密封圈,隔热衬套,第一套管悬挂,外管,保温介质,井口头,防沉板,内管,第二套管悬挂,第二套管,第一套管,保温油管组合。提供在内管、外管之间放置隔热介质的井下隔热保温组合油管代替单一普通油管用作生产管柱减少了地层能量沿井简热损失,可有效提高井口流体温度,实现了防治水合物生成的目的；同时井下隔热保温油管与常规油管配合使用,可在一定程度上降低采气成本。(The invention belongs to the technical field of reservoir drilling, and particularly relates to an underwater natural gas hydrate wellhead device with a heat preservation function. The anti-sinking well head is characterized by mainly comprising a shell, a coupling, a sealing ring, a heat insulation lining, a first casing pipe suspension, an outer pipe, a heat insulation medium, a well head, an anti-sinking plate, an inner pipe, a second casing pipe suspension, a second casing pipe, a first casing pipe and a heat insulation oil pipe. The underground heat-insulation and heat-preservation combined oil pipe with the heat-insulation medium placed between the inner pipe and the outer pipe is used as a production pipe column instead of a single common oil pipe, so that the heat loss of formation energy along a well is reduced, the temperature of a wellhead fluid can be effectively increased, and the purpose of preventing and controlling the generation of hydrates is realized; meanwhile, the underground heat-insulating oil pipe is matched with a conventional oil pipe for use, so that the gas production cost can be reduced to a certain extent.)

1. The utility model provides an underwater natural gas hydrate wellhead assembly with heat preservation function which characterized in that: comprises a heat-insulating oil pipe (11), a shell (1), a heat-insulating structure and a sleeve structure; wherein:

the heat-insulating oil pipe (11) is arranged inside the casing structure and is connected with the inner wall of the casing structure; the sleeve structure is arranged in the heat insulation structure and is connected with the inner wall of the heat insulation structure; the heat insulation structure comprises an outer pipe (3), a heat insulation medium (4) and an inner pipe (7), and the heat insulation medium (4) is arranged between the outer pipe (3) and the inner pipe (7); the heat insulation structure is arranged in the shell (1), and the outer wall of an outer pipe (3) of the heat insulation structure is connected with the inner wall of the shell (1); the inner wall of the inner pipe (7) of the heat insulation structure is connected with the sleeve structure.

2. The underwater natural gas hydrate wellhead device with the heat preservation function as claimed in claim 1, wherein: the casing structure comprises a first casing suspension (2), a second casing suspension (8), a first casing (10) and a second casing (9); the second casing hanger (8) is arranged at the lower end of the first casing hanger (2) and is fixedly connected with the first casing hanger (2); the second sleeve (9) is arranged at the lower end of the first sleeve (10) and is connected with the first sleeve (10); the first casing (10) and the second casing (9) are respectively arranged inside the first casing suspension (2) and the second casing suspension (8), and the first casing (10) and the second casing (9) respectively correspond to the spatial positions of the first casing suspension (2) and the second casing suspension (8); the heat-insulating oil pipe (11) is arranged at the lower end of the second casing pipe (9) and is connected with the inner wall of the second casing pipe suspension (8).

3. The underwater natural gas hydrate wellhead device with the heat preservation function as claimed in claim 1, wherein: a wellhead head (5) and an anti-sinking plate (6) are arranged on the outer side of the shell (1), and the wellhead head (5) is arranged between the shell (1) and the anti-sinking plate (6); the shell (1) is in a step shape, a conical bearing block (12) is arranged at the small diameter of the shell (1), and an annular groove for installing an underwater release ring (13) is arranged at the large diameter of the shell (1); the shell (1) is fixedly connected with the wellhead head (5) through a conical bearing block (12).

4. The underwater natural gas hydrate wellhead device with the heat preservation function as claimed in claim 2, wherein: an anti-wear bushing (14) and a steel ring groove (15) are arranged below the upper end of the first sleeve (10); the anti-wear bushing (14) is arranged between the steel ring groove (15) and the first sleeve (10) and is arranged inside the first sleeve suspension (2); the steel ring groove (15) is positioned at the upper end of the first sleeve hanger (2) and is arranged in the shell (1).

5. The underwater natural gas hydrate wellhead device with the heat preservation function as claimed in claim 1, wherein: flaring structures are arranged at two ends of the inner pipe (7) and are fixedly connected to the inner wall of the outer pipe (3) through the flaring structures; the pipe joints of the heat-insulation oil pipes (11) are provided with heat-insulation bushings (18), and the inner pipes (7) at the outer sides of the two heat-insulation oil pipes (11) are communicated through the heat-insulation bushings (18); the two ends of the heat insulation lining (18) are both provided with conical structures, and the conical structures of the heat insulation lining (18) are inserted into the flaring structures of the inner pipe (7) and bonded through high-strength adhesive.

6. The underwater natural gas hydrate wellhead device with the heat preservation function as claimed in claim 1, wherein: a coupling (16) is further arranged at the pipe joint of the heat-insulating oil pipe (11), and trapezoidal threads are arranged on the coupling (16); the outer pipes (3) of the heat insulation structure at the outlet of the two heat insulation oil pipes (11) are rotatably connected through a coupling (16); and a sealing ring (17) for ensuring the sealing performance between the outer pipes (3) is arranged at the position, close to the joint, of the inner wall of the coupling (16).

Technical Field

The invention belongs to the technical field of reservoir drilling, and particularly relates to an underwater natural gas hydrate wellhead device with a heat preservation function.

Background

The existing methanol injection deblocking process has three major disadvantages that ① methanol is toxic and has certain harm, ② methanol is large in using amount and high in total cost, ③ methanol injection, waste water treatment equipment and supporting facilities are large in investment and difficult to meet the requirements of low-cost and environment-friendly development of a gas field, the temperature of a shaft fluid can be effectively increased by the underground heat insulation oil pipe heat preservation process, the purpose of preventing hydrate from being generated is achieved, the process avoids stratum damage caused by injection of a deblocking agent into the shaft, and the green and environment-friendly production requirements are met.

Disclosure of Invention

The invention aims to overcome the defects of the existing methanol injection deblocking process, and provides a wellhead device which uses a downhole heat-insulating and heat-preserving combined oil pipe instead of a single common oil pipe as a production pipe column to improve the fluid temperature of a wellhead and avoid shaft blockage so as to continuously and stably drain liquid of a gas well.

The purpose of the invention is realized by the following technical scheme: an underwater natural gas hydrate wellhead device with a heat preservation function comprises a heat preservation oil pipe, a shell, a heat preservation structure and a sleeve structure; the heat-insulating oil pipe is arranged in the casing pipe structure and is connected with the inner wall of the casing pipe structure; the sleeve structure is arranged in the heat insulation structure and is connected with the inner wall of the heat insulation structure, so that the heat insulation oil pipe is ensured to reduce the heat loss of the stratum energy along the well casing under the action of the heat insulation structure; the heat insulation structure comprises an outer pipe, a heat insulation medium and an inner pipe, wherein the heat insulation medium is arranged between the outer pipe and the inner pipe, the heat insulation medium mainly comprises argon and glass fiber, and a getter is filled in the sealed annular space to clean the polluted gas so as to keep good heat insulation performance for a long time; the heat insulation structure is arranged in the shell, and the outer wall of the outer pipe of the heat insulation structure is connected with the inner wall of the shell; the inner wall of the inner pipe of the heat insulation structure is connected with the sleeve structure.

Preferably, the casing structure comprises a first casing suspension, a second casing suspension, a first casing and a second casing; the second sleeve hanger is arranged at the lower end of the first sleeve hanger and fixedly connected with the first sleeve hanger; the second sleeve is arranged at the lower end of the first sleeve and is connected with the first sleeve; the first sleeve and the second sleeve are respectively arranged inside the first sleeve suspension and the second sleeve suspension, and the first sleeve and the second sleeve respectively correspond to the spatial positions of the first sleeve suspension and the second sleeve suspension; the heat-insulating oil pipe is arranged at the lower end of the second sleeve and is connected with the suspended inner wall of the second sleeve.

Preferably, the outer side of the shell is provided with a wellhead head and an anti-sinking plate, and the wellhead head is arranged between the shell and the anti-sinking plate, so that the stability of the whole device is ensured; the shell is stepped, a conical bearing block is arranged at the small diameter of the shell, and an annular groove for installing an underwater release ring is arranged at the large diameter of the shell; the shell is fixedly connected with the wellhead head through the conical bearing block, and the service life of the device under the action of fatigue load can be effectively prolonged through the conical bearing block.

Preferably, in order to protect the inside of the well head or the casing head from being worn or damaged, a wear-resistant bushing and a steel ring groove are arranged below the upper end of the first casing; the anti-wear bushing is arranged between the steel ring groove and the first sleeve and is arranged inside the first sleeve hanger; the steel ring groove is positioned at the upper end of the first sleeve suspension and is arranged in the shell.

Preferably, flaring structures are arranged at two ends of the inner pipe, and the inner pipe is fixedly connected to the inner wall of the outer pipe through the flaring structures; the pipe joints of the heat-insulation oil pipes are provided with heat-insulation bushings, and the inner pipes outside the two heat-insulation oil pipes are communicated through the heat-insulation bushings; the two ends of the heat insulation lining are both designed into conical structures, the conical structures of the heat insulation lining are inserted into the flaring structures of the inner pipes and are bonded through high-strength adhesive, and the high-strength adhesive can guarantee the connection strength and the heat insulation performance.

Preferably, a coupling is further arranged at the pipe joint of the heat-insulating oil pipe, trapezoidal threads are arranged on the coupling, the requirement on the tensile property of the pipe column can be met through the stepped threads, and the problem that the joint of pipe joints of the heat-insulating oil pipe is prone to fatigue fracture is effectively solved; the outer pipes of the heat insulation structures at the outlets of the two heat insulation oil pipes are rotatably connected through a coupling; a sealing ring for ensuring the sealing performance between the outer pipes is arranged at the position, close to the joint, of the inner wall of the coupling; the contact surfaces of the inner pipe, the outer pipe, the coupling and the heat insulation lining are bonded by high-strength adhesives to improve the heat insulation performance of the joint.

The invention has the following advantages:

1. the underground heat insulation and preservation combined oil pipe with the heat insulation medium placed between the inner pipe and the outer pipe replaces a single common oil pipe to be used as a production pipe column, so that the heat loss of formation energy along a well is reduced, the temperature of a wellhead fluid can be effectively increased, and the purpose of preventing and controlling the generation of hydrates is realized.

2. The underground heat-insulating oil pipe of the device can be matched with a conventional oil pipe for use, and the gas production cost can be reduced to a certain extent.

3. The coupling is a part with buttress threads between the heat-insulating oil pipes, so that the tensile property requirement of the pipe column is ensured, and the problem that the joints between the pipe joints of the heat-insulating oil pipes are easy to generate fatigue fracture is effectively solved.

4. The high-strength adhesive is used among contact surfaces of the inner pipe, the outer pipe, the coupling and the heat insulation bushing, and the heat insulation performance of a joint is effectively improved.

Drawings

FIG. 1 is a schematic view of an underwater natural gas hydrate wellhead assembly with insulation of the present invention;

FIG. 2 is a schematic view of the connection of two adjacent thermal insulation tubing joints according to the present invention;

in the figure: 1-a housing; 2-hanging the first sleeve; 3-an outer tube; 4-heat preservation medium; 5-wellhead head; 6-anti-sinking plate; 7-inner tube; 8-second casing hanging; 9-a second sleeve; 10-a first sleeve; 11-heat insulation oil pipe; 12-a conical bearing surface; 13-underwater release ring; 14-anti-wear and core-supplementing; 15-steel ring groove; 16-a coupling; 17-a sealing ring; 18-insulating lining.

Detailed Description

The invention will be further described with reference to the accompanying drawings, but the scope of the invention is not limited to the following.

As shown in fig. 1, an underwater natural gas hydrate wellhead device with a heat preservation function comprises a heat preservation oil pipe 11, a shell 1, a heat preservation structure and a casing structure; the heat-insulating oil pipe 11 is arranged inside the casing structure and is connected with the inner wall of the casing structure; the casing structure is arranged in the heat insulation structure and connected with the inner wall of the heat insulation structure, so that the heat insulation oil pipe 11 is ensured to reduce the heat loss of the formation energy along the well casing under the action of the heat insulation structure; the heat insulation structure comprises an outer pipe 3, a heat insulation medium 4 and an inner pipe 7, wherein the heat insulation medium is arranged between the outer pipe 3 and the inner pipe 7, the heat insulation medium 4 mainly comprises argon and glass fiber, and a getter is filled in a sealed annular space to clean a polluted gas so as to keep good heat insulation performance for a long time; the heat insulation structure is arranged in the shell 1, and the outer wall of an outer pipe 3 of the heat insulation structure is connected with the inner wall of the shell 1; the inner wall of the inner pipe 7 of the heat insulation structure is connected with the sleeve structure; the inner pipe 7 is in a stretching state at normal temperature, when the temperature is gradually increased, the tensile stress is reduced, the inner pipe 7 is changed from the stretching state to a compression state, and the pre-stretching of the inner pipe 7 reduces the compressive stress after the thermal stretching so as to ensure the normal work of the inner pipe.

Preferably, the casing structure comprises a first casing suspension 2, a second casing suspension 8, a first casing 10 and a second casing 9; the second casing hanger 8 is arranged at the lower end of the first casing hanger 2 and is fixedly connected with the first casing hanger 2; the second sleeve 9 is arranged at the lower end of the first sleeve 10 and is connected with the first sleeve 10; the first sleeve 10 and the second sleeve 9 are respectively arranged inside the first sleeve suspension 2 and the second sleeve suspension 8, and the first sleeve 10 and the second sleeve 9 respectively correspond to the spatial positions of the first sleeve suspension 2 and the second sleeve suspension 8; the insulating oil pipe 11 is arranged at the lower end of the second casing pipe 9 and is connected with the inner wall of the hanging part 8 of the second casing pipe 9.

Preferably, a well head 5 and an anti-sinking plate 6 are arranged on the outer side of the shell 1, and the well head 5 is arranged between the shell 1 and the anti-sinking plate 6, so that the stability of the whole device is ensured; the shell 1 is in a step shape, a conical bearing block 12 is arranged at the small diameter part of the shell 1, and an annular groove for installing an underwater release ring 13 is arranged at the large diameter part of the shell 1; the shell 1 and the wellhead head 5 are fixedly connected through the conical bearing block 12, and the service life of the device under the action of fatigue load can be effectively prolonged through the conical bearing block 12.

Preferably, in order to protect the inside of the well head 5 or the casing head from being worn or damaged, the upper end and the lower end of the first casing 10 are provided with a wear-resistant bushing 14 and a steel ring groove 15; the anti-wear bushing 14 is arranged between the steel ring groove 15 and the first sleeve 10 and is arranged inside the first sleeve suspension 2; the steel ring groove 15 is positioned at the upper end of the first sleeve hanger 2 and is arranged in the shell 1.

As shown in fig. 2, the two ends of the inner tube 7 are provided with flaring structures, and the inner tube 7 is fixedly connected to the inner wall of the outer tube 3 through the flaring structures; the pipe joints of the heat-insulation oil pipes 11 are provided with heat-insulation bushings 18, and the inner pipes 7 outside the two heat-insulation oil pipes 11 are communicated through the heat-insulation bushings 18; the two ends of the heat insulation lining 18 are both designed into conical structures, the conical structures of the heat insulation lining 18 are inserted into the flaring structures of the inner pipe 7 and are bonded through high-strength adhesive, and the high-strength adhesive can guarantee the connection strength and the heat insulation performance.

Preferably, a coupling 16 is further arranged at the pipe joint of the heat-insulating oil pipe 11, trapezoidal threads are arranged on the coupling 16, the requirement of tensile property of the pipe column can be met by the stepped threads, and the problem that the joint of the pipe joint of the heat-insulating oil pipe 11 is prone to fatigue fracture is effectively solved; the outer pipes 3 of the heat insulation structure at the outlets of the two heat insulation oil pipes 11 are rotatably connected through a coupling 16; a sealing ring 17 for ensuring the sealing performance between the outer pipes 3 is arranged at the position, close to the joint, of the inner wall of the coupling 16; the contact surfaces of the inner pipe 7, the outer pipe 3, the coupling 16 and the heat insulation bush 18 are bonded by high-strength adhesive, so that the heat insulation performance of the joint is improved.

The working process of the invention is as follows: argon and glass fiber heat-insulating medium 4 are placed between the inner pipe 7 and the outer pipe 3 to insulate the natural gas hydrate, so that the gas well can continuously and stably discharge liquid.