Double-wall drill rod with heat insulation function

Abstract

The utility model provides a double-wall drill rod with a heat insulation function. The double-wall drill rod comprises an outer pipe and an inner pipe which are connected in a sleeved mode, a heat insulation layer is arranged between the outer pipe and the inner pipe, an outer pipe male connector is arranged at one end of the outer pipe, an outer pipe female connector is arranged at the other end of the outer pipe, an inner pipe female connector is arranged at one end of the inner pipe, and an inner pipe male connector is arranged at the other end of the inner pipe. One end of the outer pipe male connector is in threaded connection with the outer pipe, first external threads are arranged on the outer wall of the other end of the outer pipe male connector, one end of the outer pipe female connector is in threaded connection with the outer pipe, first internal threads are arranged on the inner wall of the other end of the outer pipe female connector, and the first internal threads are matched with the first external threads. According to the scheme, the double-wall drill rod is of a double-wall structure, the heat insulation material is embedded in the double-wall drill rod, the good heat insulation effect can be achieved, the double-wall drill rod can adapt to different working environments by arranging the sealing ring, preventing the heat insulation material from leaking, adopting the split type design and replacing the connector, and drilling operation can be safely and reliably conducted in the high-temperature and high-pressure environment.

Description

Technical Field

[0001] The utility model relates to the technical field of oil drilling, in particular to a double-wall drill rod with heat insulation function. Background Art

[0002] In the field of oil drilling engineering, with the continuous development of deep underground drilling, the high temperature downhole caused by geothermal gradient has an increasingly obvious impact on drilling work. At present, among the conventional methods for dealing with high temperature and ultra-high temperature problems, on the one hand, the temperature bearing capacity of drilling fluid and downhole tools is improved, and on the other hand, drilling fluid coolers are applied on the ground. In terms of temperature bearing capacity, the current development of various technologies has gradually reached a bottleneck, and it is difficult to make a major breakthrough; ground drilling fluid coolers can be used to reduce the temperature of drilling fluid returning to the wellhead, but the effect on reducing the bottom hole circulation temperature is limited, and the reduction is generally below 10°C.

[0003] The current insulated drill pipe is welded to a conventional drill pipe with a liner. This structure will affect the integrity of the drill pipe structure to a certain extent, and will also affect the flow of the water hole fluid. The sealing will also be weakened due to the influence of the fluid scouring for a long time. At the same time, because the insulation material with high compressive strength is selected, the choice of insulation material types will be limited to a certain extent, thereby affecting the insulation effect. Utility Model Content

[0004] The utility model provides a double-wall drill pipe with a heat-insulating function to solve the technical problem that the current heat-insulating drill pipe is arranged on a conventional drill pipe by welding, which will affect the integrity of the drill pipe structure to a certain extent and affect the flow of water hole fluid.

[0005] In order to solve the above technical problems, the utility model provides the following technical solutions:

[0006] A double-wall drill pipe with a heat insulation function, comprising an outer tube and an inner tube which are sleeved with each other, a heat insulation layer being provided between the outer tube and the inner tube, characterized in that one end of the outer tube is provided with an outer tube male joint, and the other end is provided with an outer tube female joint, one end of the inner tube is provided with an inner tube female joint, and the other end is provided with an inner tube male joint; one end of the outer tube male joint is threadedly connected to the outer tube, and a first outer thread is provided on the outer wall of the other end, one end of the outer tube female joint is threadedly connected to the outer tube, and a first inner thread is provided on the inner wall of the other end, and the first inner thread is adapted to the first outer thread; one end of the inner tube female joint is threadedly connected to the inner tube, and a plug-in groove is provided on the inner wall of the other end, one end of the inner tube male joint is threadedly connected to the inner tube, and a plug-in protrusion is provided at the other end, and the plug-in protrusion is adapted to the plug-in groove.

[0007] Among them, the inner wall of the outer tube male joint and the inner wall of the outer tube female joint are both provided with sealing protrusions, the sealing protrusions are located at both ends of the outer tube and in contact with the outer wall of the inner tube, the sealing protrusions and the inner wall of the outer tube and the outer wall of the inner tube together form a sealed accommodating cavity, and the accommodating cavity is provided with insulation material.

[0008] Wherein, the inner wall of the outer tube male joint and the inner wall of the outer tube female joint are both provided with a first installation groove, and a sealing ring is arranged in the first installation groove.

[0009] Among them, the inner tube female joint is located on the inner side of the outer tube male joint, and the inner tube male joint is located on the inner side of the outer tube female joint; a second installation groove is opened on the inner wall of the outer tube female joint, a retaining ring is arranged in the second installation groove, and a limiting boss is arranged on the outer wall of the inner tube male joint, and the retaining ring axially limits the inner tube male joint by clamping the limiting boss.

[0010] Wherein, the first external thread and the first internal thread are trapezoidal threads.

[0011] Wherein, connecting parts are provided at both ends of the outer tube, and a second external thread is provided on the outer wall of the connecting part. The second external thread is a trapezoidal thread, and the outer tube male joint and the outer tube female joint are provided with a second internal thread adapted to the second external thread.

[0012] Wherein, the outer wall of the outer tube male joint and the outer wall of the outer tube female joint are both provided with a plane groove.

[0013] Wherein, both ends of the inner tube are provided with a third external thread, the third external thread is a fine pitch thread, and the inner tube female joint and the inner tube male joint are provided with a third internal thread adapted to the third external thread.

[0014] The beneficial effects of the above technical solution of the utility model are as follows:

[0015] In the above scheme, the double-wall drill pipe adopts a double-wall structure and is provided with an insulation layer, which can effectively reduce the temperature difference between the inner and outer pipes and achieve a good insulation effect; a split design is adopted to connect the drill pipe through a male connector and a female connector. Replacing the connector can adapt to different working environments and reduce maintenance costs; the double-wall drill pipe takes into account the mechanical properties and temperature differences underground, and can safely and reliably perform drilling operations in high temperature and high pressure environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a cross-sectional view of the double-wall drill pipe of the utility model;

[0017] Figure 2 This is a schematic diagram of the structure of the double-wall drill pipe of the utility model;

[0018] Figure 3 It is a schematic diagram of the connection between the outer tube and the outer tube male connector of the utility model;

[0019] Figure 4 This is a schematic diagram of the connection between the outer tube and the outer tube female joint of the utility model;

[0020] Figure 5 This is a schematic diagram of the connection between the inner tube and the inner tube female joint of the utility model;

[0021] Figure 6 It is a schematic diagram of the connection between the inner tube and the inner tube male joint of the utility model;

[0022] Figure 7 It is a schematic diagram of the connection between the outer tube female joint and the outer tube male joint of the utility model;

[0023] Figure 8 It is a schematic diagram of the connection between the inner tube male connector and the inner tube female connector of the utility model;

[0024] Fig. 9 This is a schematic diagram of the connection of the double-wall drill pipe of the utility model;

[0025] Fig.10 This is a structural diagram of the end portion of the outer tube of the utility model;

[0026] Fig.11 This is a structural diagram of the end portion of the inner tube of the utility model;

[0027] Fig.12 It is a cross-sectional view of the outer pipe male connector of the utility model;

[0028] Fig.13 It is a cross-sectional view of the outer pipe female joint of the utility model;

[0029] Fig.14 It is a side view of the inner tube male connector of the utility model;

[0030] Fig.15 It is a side view of the inner pipe female joint of the utility model.

[0031] [Reference Signs]

[0032] 1. Outer tube; 2. Inner tube; 3. Male connector for outer tube; 4. Female connector for outer tube;

[0033] 5. Male connector for inner tube; 6. Female connector for inner tube; 7. Heat insulation material; 8. Sealing ring;

[0034] 9. Retaining ring. DETAILED DESCRIPTION

[0035] In order to make the technical problems to be solved, technical solutions and advantages of the present invention more clear, a detailed description will be given below in conjunction with the accompanying drawings and specific embodiments.

[0036] like Figure 1 to Figure 15 As shown, an embodiment of the utility model provides a double-wall drill pipe with a heat insulation function, comprising an outer tube 1 and an inner tube 2 which are sleeved with each other, a heat insulation layer is provided between the outer tube 1 and the inner tube 2, one end of the outer tube 1 is provided with an outer tube male joint 3, and the other end is provided with an outer tube female joint 4, one end of the inner tube 2 is provided with an inner tube female joint 6, and the other end is provided with an inner tube male joint 5; one end of the outer tube male joint 3 is threadedly connected to the outer tube 1, and a first external thread is provided on the outer wall of the other end, one end of the outer tube female joint 4 is threadedly connected to the outer tube 1, and a first internal thread is provided on the inner wall of the other end, and the first internal thread is adapted to the first external thread; one end of the inner tube female joint 6 is threadedly connected to the inner tube 2, and a plug-in groove is provided on the inner wall of the other end, one end of the inner tube male joint 5 is threadedly connected to the inner tube 2, and a plug-in protrusion is provided at the other end, and the plug-in protrusion is adapted to the plug-in groove.

[0037] like Figure 8 and Fig. 9 As shown, the plug-in protrusion of the inner tube male connector 5 can be inserted into the plug-in groove of the inner tube female connector 6, and a PTA (Pure Terephthalic Acid) spring seal ring can be installed between them for sealing to prevent leakage of drilling fluid. After the outer tube female connector 4 of one drill pipe is threadedly connected with the outer tube male connector 3 of another drill pipe, the plug-in protrusion of the inner tube male connector 5 of the drill pipe will be inserted into the plug-in groove of the inner tube female connector 6 of the other drill pipe to achieve the connection of the two drill pipes.

[0038] like Figure 1 As shown, the inner wall of the outer tube male joint 3 and the inner wall of the outer tube female joint 4 are both provided with sealing protrusions, which are located at both ends of the outer tube 1 and in contact with the outer wall of the inner tube 2. The sealing protrusions and the inner wall of the outer tube 1 and the outer wall of the inner tube 2 together form a sealed accommodating cavity, and a heat insulating material 7 is arranged in the accommodating cavity. In this embodiment, the heat insulating material 7 is made of polyimide.

[0039] The inner wall of the outer tube male joint 3 and the inner wall of the outer tube female joint 4 are both provided with a first installation groove, and a sealing ring 8 is arranged in the first installation groove to further seal the thermal insulation material 7. In this embodiment, the sealing ring 8 adopts a PTA spring sealing ring, the sealing ring groove adopts an open design, and a retaining ring is added to form a combined seal, the assembly process is convenient, and the sealing effect is reliable.

[0040] like Figure 1As shown, the inner tube female joint 6 is located on the inner side of the outer tube male joint 3, and the inner tube male joint 5 is located on the inner side of the outer tube female joint 4. The inner wall of the outer tube female joint 4 is also provided with a second mounting groove, in which a retaining ring 9 is arranged, and a limiting boss with a diameter of 70 mm is arranged on the outer wall of the inner tube male joint 5, and the retaining ring 9 axially limits the inner tube male joint 5 by clamping the limiting boss.

[0041] In this embodiment, the first external thread and the first internal thread are trapezoidal threads with a taper of 1:10 and a length of 44mm. The outer diameter of the outer tube 1 is 102mm, the inner diameter is 96mm, and connecting parts are provided at both ends. The outer wall of the connecting part is processed with a second external thread. The second external thread is a trapezoidal thread with a taper of 1:22 and a length of 44mm. The outer tube male connector 3 and the outer tube female connector 4 are provided with a second internal thread that matches the second external thread. Both ends of the second external thread leave an 8mm smooth part (unprocessed thread), the total length of the connecting part is 60mm, and the tolerance is +0.05~+0.1mm, to ensure that the outer tube male connector 3 and the outer tube female connector 4 do not cooperate with the root of the thread when connected to prevent the cooperation from being too loose and causing leakage.

[0042] The outer diameters of the outer tube male connector 3 and the outer tube female connector 4 are 105 mm. Fig.12 and Fig.13 As shown, the outer wall of the outer tube male joint 3 and the outer wall of the outer tube female joint 4 are both provided with a plane groove for easy installation.

[0043] The outer diameter of the inner tube 2 is 50mm, the inner diameter is 38mm, and a third external thread is processed at both ends. The third external thread is M50-6g ordinary fine thread with a length of 30mm. The use of fine thread can enhance the sealing performance. The inner tube female joint 6 and the inner tube male joint 5 are provided with a third internal thread that matches the third external thread. A 100mm area at both ends of the outer wall of the inner tube 2 is processed with a roughness of Ra1.6, the purpose of which is to cooperate with the sealing ring 8.

[0044] In this embodiment, the outer diameters of the inner tube female joint 6 and the inner tube male joint 5 are both 50 mm. The inner wall of the inner tube female joint 6 is provided with a third installation groove for installing a PTA spring seal ring, and the roughness requirement is Ra1.6, in order to extend the service life of the seal ring and prevent the seal ring from being damaged under high pressure. The plug-in protrusion of the inner tube male joint 5 is cylindrical with a diameter of 45.5 mm, and the roughness requirement is Ra1.6, in order to cooperate with the PTA spring seal ring in the inner tube female joint 6 of another drill pipe.

[0045] In the above scheme, the double-wall drill pipe adopts a double-wall structure and is embedded with thermal insulation material, which can effectively reduce the temperature difference between the inner and outer pipes and achieve a good thermal insulation effect; by setting a sealing ring, the sealing effect of the thermal insulation material is enhanced to prevent leakage of the thermal insulation material; a split design is adopted to connect the drill pipe through a male connector and a female connector, and the replacement of the connector can adapt to different working environments and reduce maintenance costs; the double-wall drill pipe takes into account the mechanical properties and temperature differences underground, and can safely and reliably perform drilling operations under high temperature and high pressure environments.

[0046] The above is a preferred embodiment of the present invention. It should be pointed out that, for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. A double-wall drill pipe with heat insulation function, comprising an outer tube and an inner tube which are sleeved together, and a heat insulation layer is provided between the outer tube and the inner tube, characterized in that: One end of the outer tube is provided with an outer tube male joint, and the other end is provided with an outer tube female joint; one end of the inner tube is provided with an inner tube female joint, and the other end is provided with an inner tube male joint; One end of the external tube male joint is threadedly connected to the external tube, and a first external thread is arranged on the outer wall of the other end; one end of the external tube female joint is threadedly connected to the external tube, and a first internal thread is arranged on the inner wall of the other end, and the first internal thread is adapted to the first external thread; One end of the inner tube female joint is threadedly connected to the inner tube, and the inner wall of the other end is provided with a plug-in groove; one end of the inner tube male joint is threadedly connected to the inner tube, and the other end is provided with a plug-in protrusion, and the plug-in protrusion is adapted to the plug-in groove.

2. The double-wall drill pipe with heat insulation function according to claim 1, characterized in that: The inner wall of the outer tube male joint and the inner wall of the outer tube female joint are both provided with sealing protrusions, the sealing protrusions are located at both ends of the outer tube and are in contact with the outer wall of the inner tube, the sealing protrusions and the inner wall of the outer tube and the outer wall of the inner tube together form a sealed accommodating cavity, and the accommodating cavity is provided with a heat insulating material.

3. The double-wall drill pipe with heat insulation function according to claim 2, characterized in that: The inner wall of the outer tube male joint and the inner wall of the outer tube female joint are both provided with a first installation groove, and a sealing ring is arranged in the first installation groove.

4. The double-wall drill pipe with heat insulation function according to claim 1, characterized in that: The inner tube female joint is located on the inner side of the outer tube male joint, and the inner tube male joint is located on the inner side of the outer tube female joint; A second mounting groove is formed on the inner wall of the outer tube female joint, a retaining ring is arranged in the second mounting groove, a limiting boss is formed on the outer wall of the inner tube male joint, and the retaining ring axially limits the inner tube male joint by clamping the limiting boss.

5. The double-wall drill pipe with heat insulation function according to claim 1, characterized in that: The first external thread and the first internal thread are trapezoidal threads.

6. The double-wall drill pipe with heat insulation function according to claim 1, characterized in that: The two ends of the outer tube are provided with connecting parts, the outer wall of the connecting part is provided with a second external thread, the second external thread is a trapezoidal thread, and the outer tube male joint and the outer tube female joint are provided with a second internal thread adapted to the second external thread.

7. The double-wall drill pipe with heat insulation function according to claim 1, characterized in that: The outer wall of the outer tube male joint and the outer wall of the outer tube female joint are both provided with a plane groove.

8. The double-wall drill pipe with heat insulation function according to claim 1, characterized in that: The two ends of the inner tube are provided with a third external thread, the third external thread is a fine pitch thread, and the inner tube female joint and the inner tube male joint are provided with a third internal thread matched with the third external thread.

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