Liquid nitrogen perforation fracturing shaft

Abstract

The utility model relates to the field of indoor petroleum engineering tests, in particular to a liquid nitrogen perforation fracturing shaft which comprises a shaft body, a controllable exhaust pipe, an assembly type plastic perforation, a bolt, a round threaded sealing cover and a special hexagonal wrench. The assembly type plastic perforation, the bolt and the round threaded sealing cover can be connected with or detached from the shaft body, the problem that fracturing fluid is injected downwards unsuccessfully due to phase change of the tip end of liquid nitrogen is solved through the device, and indoor liquid nitrogen fracturing tests can be carried out easily. By means of the matched design, the accuracy of the indoor liquid nitrogen perforation test can be improved, early-stage preparation and later-stage cleaning of the test are faster, and the efficiency of the test can be improved.

Description

Technical Field

[0001] This test application relates to the field of indoor petroleum engineering tests, which is a petroleum engineering test device, and in particular to a liquid nitrogen perforating and fracturing wellbore. Background Art

[0002] During the liquid nitrogen fracturing process, liquid nitrogen can reduce the temperature of the rock on the main fracture surface, produce a cooling and fracturing effect on the rock, and its effect is expected to form more micro-cracks on the main fracture surface. Due to the deep burial of the reservoir in the on-site construction, it is difficult to effectively observe the crack expansion morphology, and the cost of engineering construction is high, so physical experiments are often used for equivalent research. When liquid nitrogen is injected downward, the tip phase change causes excessive gas pressure, and conventional fracturing equipment is difficult to effectively pump in fracturing fluid. In order to avoid a series of problems such as the failure of liquid nitrogen downward injection, this patent designs a liquid nitrogen perforating fracturing wellbore, which can effectively avoid the backflow of the wellhead caused by the gasification of liquid nitrogen, and can also effectively realize the perforating fracturing simulation of indoor artificial samples. Summary of the invention

[0003] In order to solve the problem that the conventional fracturing equipment is difficult to effectively pump fracturing fluid due to phase change at the tip of liquid nitrogen, the utility model provides a liquid nitrogen perforating fracturing wellbore.

[0004] The new wellbore includes a wellbore body consisting of an outer wellbore and an inner wellbore, a controllable exhaust pipe, an assembled plastic perforation, a special hexagonal wrench, a foam pad, and a cylindrical threaded cap. The perforations on the wellbore wall can be disassembled and installed according to the angle and spacing requirements, and the bolts that match the shape and size of the perforations can be used to block idle holes. The controllable exhaust pipe is used to control the flow of gas, the hexagonal wrench is used to more conveniently disassemble and install the bolts, the foam pad can be used to prevent concrete from entering the perforations, and the cylindrical threaded cap is used to form a closed space at the bottom. The wellbore body, the assembled plastic perforation, the assembled bolts, the cylindrical threaded cap, and the controllable exhaust pipe are connected to each other to form a new liquid nitrogen perforating fracturing wellbore.

[0005] The new wellbore device described: the fixed hexagonal prism part at the top of the main body outer wellbore has a side length of 15mm, an inner diameter of 4mm, and a height of 10mm. The upper and lower ends are provided with threads with a height of 3mm. The lower outer wellbore is 200mm long, with an inner diameter of 14mm and an outer diameter of 17mm. The lower end is provided with a thread with a height of 5mm. The upper and lower ends are open. The side of the outer wellbore is connected to a controllable exhaust pipe with a length of 50mm, an outer diameter of 8mm, and an inner diameter of 6mm. It is 15mm away from the top. The rightmost end of the controllable exhaust pipe is provided with a thread with a height of 3mm and a diameter of 8mm. There is an exhaust valve 35mm away from the right end to control the opening and closing of the airflow. The lower inner wellbore is 170mm long, with an inner diameter of 4mm and an outer diameter of 10mm. The upper end is provided with a thread with a height of 3mm, and the upper and lower ends are open. In order to ensure the stability of the wellbore during the test, three cylinders with a diameter of 20mm, a height of 5mm, and a distance of 8mm are set for fixing, 25mm away from the top. The assembled perforation has an outer diameter of 5mm, an inner diameter of 3mm, and a total length of 25mm. The lower end is provided with a 5.5mm high thread. There are six layers of perforations 60mm below the top. The perforations are 6.5mm long and 5mm in diameter. Each layer has three perforations. The perforations are evenly distributed at 120°. The adjacent two layers of perforations are staggered at 60°, and each layer of perforations is 15mm apart. The bolt has a diameter of 5mm and a length of 5.5mm. The lower end is provided with a 5.5mm high thread. For easy installation and disassembly, a hexagonal groove with a side length of 2mm and a depth of 3mm is set in the center of its top, and it is equipped with a hexagonal wrench with a side length of 3mm and a total length of 15cm. The lower end of the cylindrical thread cover is 5mm high and 20mm in diameter, and the upper end is provided with a cylindrical thread with a height of 5mm and a diameter of 14mm.

[0006] The beneficial effects achieved by the utility model are: providing a fracturing tool for liquid nitrogen fracturing test, solving the problem of failure of fracturing fluid downward injection due to phase change at the tip of liquid nitrogen, effectively solving the problem of difficulty in effectively pumping fracturing fluid into conventional fracturing equipment, and carrying out assembly and design of the wellbore, which can realize multi-angle and multi-spacing perforation fracturing, and facilitate multi-angle injection of liquid nitrogen fracturing test according to needs. The equipment disassembly and assembly process is simple, which improves the efficiency of the test.

[0007] The new wellbore device

[0008] The utility model is easy to install and use, and can solve the problem that the fracturing fluid is difficult to effectively pump in due to the phase change of the liquid nitrogen tip. The injection angle and spacing required for the test can be easily adjusted, and the angle can be ensured to be stable. In addition, it is convenient to disassemble and assemble the sample after the test, and effectively speed up the test process. The material used in the device is iron and plastic material, which is easy to obtain, can ensure the accuracy of the test, and can be widely promoted and used. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Other features, purposes and advantages of the present invention will become more apparent by reading and referring to the following drawings and detailed description:

[0010] Figure 1 This is a schematic diagram of a wellbore structure for liquid nitrogen perforation fracturing according to the utility model;

[0011] Figure 2 This is a schematic diagram of the main structure of a liquid nitrogen perforating and fracturing wellbore of the utility model;

[0012] Figure 3 This is a schematic diagram of a plastic perforating structure that can be assembled in a liquid nitrogen perforating and fracturing wellbore according to the utility model;

[0013] Figure 4 This is a schematic diagram of a liquid nitrogen perforating and fracturing wellbore bolt structure of the utility model;

[0014] Figure 5 The utility model is a schematic diagram of a special cylindrical threaded cover structure.

[0015] Figure 6 This is a schematic diagram of a controllable exhaust pipe structure for a liquid nitrogen perforating and fracturing wellbore according to the utility model;

[0016] Figure 7 The utility model is a schematic diagram of a special hexagonal wrench structure.

[0017] like Figure 1 As shown: (1) wellbore body, (2) assembled plastic perforator, (3) controllable exhaust pipe, (4) bolts and (5) cylindrical threaded cover. DETAILED DESCRIPTION

[0018] In order to make the technical means, creative features, objectives and effects achieved by the present invention easy to understand, the present invention is further described below in conjunction with specific implementation methods.

[0019] See also Figure 1 The utility model provides a technical solution: a liquid nitrogen perforating and fracturing wellbore, comprising (1) a wellbore body, (2) an assemblable plastic perforator, (3) a controllable exhaust pipe, (4) a bolt, (5) a cylindrical threaded cover, and (6) a hexagonal wrench.

[0020] In this example, first, the (3) controllable exhaust pipe is connected to the (1) wellbore body by threads, and the (5) cylindrical threaded cover is connected to the (1) wellbore body by upper thread. According to the angle and spacing required for each test, when necessary, the required small holes are selected and the (2) assembled plastic perforator is installed on the (1) wellbore body by threads, and the unused holes are blocked with (6) hexagonal wrench and (4) bolts. After the bolts are installed, the outer wall of the (1) wellbore body is flat and will not affect the subsequent tests. In addition, before the sample is cast, the (2) liquid nitrogen plastic perforator needs to be blocked with a foam pad to prevent concrete from entering. After the test, the (1) wellbore body is taken out, the (3) controllable exhaust pipe and (5) cylindrical threaded cover are removed from the (1) wellbore body, and the (2) liquid nitrogen plastic perforator and (4) bolts are removed with the (6) hexagonal wrench for the next use.

[0021] The above describes the basic principle, main features and advantages of the utility model. For those skilled in the art, the utility model is not limited to the details in the above exemplary embodiments, and can be embodied in other specific forms without departing from the characteristics of the utility model. In addition, it should be known that although this specification is described according to the implementation mode, not every implementation has only one technical solution, and the description of the specification is only for the convenience of understanding.

[0022] Those skilled in the art should regard the specification as a whole, and the technical solutions in each implementation case can also be appropriately combined to form an implementation plan that everyone can understand.

Claims

1. A liquid nitrogen perforating and fracturing wellbore, characterized in that: The wellbore body, the assemblable plastic perforator, the controllable exhaust pipe, the bolts, and the cylindrical threaded cap are composed of five parts. In addition, a special hexagonal wrench is provided. The holes in the wellbore body that need to be cast at an angle can be engaged with the assemblable plastic perforator by means of matching threads. The casting angles that are not used temporarily can be engaged with the holes on the wellbore wall by means of bolts through the use of a hexagonal wrench. The upper end of the wellbore wall is engaged with the controllable exhaust pipe by means of matching threads, and the bottom of the wellbore is connected to the cylindrical threaded cap by matching threads, thus forming a complete wellbore.

2. A liquid nitrogen perforating and fracturing wellbore according to claim 1, characterized in that: The wellbore body and the assembled plastic perforators, controllable exhaust pipes, bolts, and cylindrical threaded covers can be easily installed and disassembled by means of the threaded structure.

3. A liquid nitrogen perforating and fracturing wellbore according to claim 2, characterized in that: The outer wellbore of the wellbore body is 200mm long, with an inner diameter of 14mm, an outer diameter of 17mm, open at the upper and lower ends, and a 5mm high thread at the lower end. The inner wellbore of the wellbore body is 170mm long, with an inner diameter of 4mm, an outer diameter of 10mm, open at the upper and lower ends, and a 3mm high thread at the upper end.

4. A liquid nitrogen perforating and fracturing wellbore according to claim 3, characterized in that: The fixed hexagonal prism part at the top of the main outer shaft has a side length of 15mm, an inner diameter of 4mm, and a height of 10mm. The lower end is provided with a thread 3mm high. Three cylinders with a diameter of 20mm, a height of 5mm, and a spacing of 8mm are provided 25mm away from the top for fixation.

5. A liquid nitrogen perforating and fracturing wellbore according to claim 2, characterized in that: The assembled plastic perforator has an outer diameter of 5mm, an inner diameter of 3mm, a total length of 25mm, and a 5.5mm high thread at the lower end.

6. A liquid nitrogen perforating and fracturing wellbore according to claim 2, characterized in that: The bolt has a diameter of 5mm, a length of 5.5mm, and a 5.5mm high thread at the lower end.

7. A liquid nitrogen perforating and fracturing wellbore according to claim 2, characterized in that: The controllable exhaust pipe is 50mm long, 8mm in outer diameter, 6mm in inner diameter, 15mm from the top of the shaft, with a thread height of 3mm at the far right end and an exhaust valve 35mm from the right end. Control the air flow on and off.

8. The liquid nitrogen perforating and fracturing wellbore according to claim 2, characterized in that: The lower end of the cylindrical threaded cover is 5mm high and 20mm in diameter, and the upper end is provided with a cylindrical thread with a height of 5mm and a diameter of 14mm.

9. The liquid nitrogen perforating and fracturing wellbore according to claim 1, characterized in that The thread at the perforation on the wellbore is the same in size and shape as the assembled plastic perforation and the thread at the end of the bolt. The thread at the bottom of the wellbore and the cylindrical threaded cover is the same in size and shape.

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