Oilfield wellhead leak-proof casing head

Abstract

The application discloses an oilfield wellhead anti-leakage casing head in the technical field of oil well exploitation equipment, which comprises a lower casing head and an upper casing head, the lower casing head is connected with the lower end of the upper casing head, the upper end of the upper casing head is connected with a mounting joint, the connecting position of the lower casing head and the upper casing head and the connecting position of the upper casing head and the mounting joint are both provided with built-in sealing pieces, the built-in sealing pieces comprise a circulating pump, the circulating pump is fixedly installed on the outer side of the upper casing head and connected with a condenser through an external hose, a filling piece is filled with anti-freezing liquid, the filling piece is fixedly installed with a connecting pipe, the other end of the connecting pipe is fixedly connected with the circulating pump, the circulating pump can drive the anti-freezing liquid to circulate between the filling piece and the condenser, and the outer surface of the filling piece is elastic, the anti-freezing liquid is injected into the filling piece, the filling piece is expanded to serve as a sealing piece of a connecting gap, and the influence of oil leakage caused by the dislocation of a traditional sealing piece is avoided.

Description

Technical Field

[0001] This invention relates to the field of oil well production equipment technology, specifically to a casing head for preventing leakage at oilfield wellheads. Background Technology

[0002] The casing head is used to fix the wellhead of the drilled well, connect the wellhead casing string, support the weight of the technical casing and the oil layer casing, seal the annular space between each layer of casing, provide a transition connection for the installation of blowout preventers, tubing heads, and Christmas trees, and through the two side ports on the casing head body, construction operations such as mud filling, monitoring, and adding balancing fluid can be performed. Currently, the joints of casing heads are sealed with conventional sealing gaskets. Due to the unavoidable vibration generated during the operation of drilling and production equipment, the sealing gaskets are prone to misalignment after long-term use, resulting in a deterioration of the sealing effect of the casing head, and oil can easily leak from the joint of the casing head. Summary of the Invention

[0003] The technical problem of this invention is to provide a casing head for preventing leakage at oilfield wellheads, in which antifreeze is injected into the filler, causing the filler to expand and act as a sealant for the connection gap, thus avoiding the oil leakage caused by misalignment of traditional seals.

[0004] To achieve the above objectives, the present invention provides the following technical solution: a casing head for preventing leakage at oilfield wellheads, comprising a lower casing head and an upper casing head, wherein the lower ends of the lower casing head and the upper casing head are connected, and an installation joint is connected to the upper end of the upper casing head. Built-in seals are provided at the connection points between the lower casing head and the upper casing head, and at the connection points between the upper casing head and the installation joint. The built-in seals include: a circulation pump, which is fixedly installed on the outside of the upper casing head, and the circulation pump is connected to a condenser via an external hose.

[0005] A filler is provided, which is filled with antifreeze. A connecting pipe is fixedly installed on the filler, and the other end of the connecting pipe is fixedly connected to the circulation pump. The circulation pump can drive the antifreeze to circulate between the filler and the condenser. The outer surface of the filler is elastic.

[0006] The filler includes a lower filler plug and an inner filler plug. The lower filler plug is an annular rubber plug with a hollow interior. Two sets of lower filler plugs are stacked on top of each other at the connection between the lower sleeve head and the upper sleeve head. A lower protective ring is provided on the inner wall between the lower sleeve head and the upper sleeve head. The lower filler plug is wrapped between the inner wall of the lower sleeve head and the lower protective ring.

[0007] The inner filler plug is a hollow annular part with an opening at the lower end. The side of the inner filler plug near the inner wall of the lower sleeve head is provided with an elastic inner layer. An upper protective ring is fixedly installed on the inner side of the upper sleeve head, and the upper protective ring wraps the inner filler plug inside. An antifreeze groove is opened at the upper end of the upper sleeve head, and the lower opening of the inner filler plug is embedded in the antifreeze groove.

[0008] As a further embodiment of the present invention, the upper connecting pipe is connected to the antifreeze tank, and the lower end is connected to the circulation pump. One end of the lower connecting pipe is connected to the hollow lower filling plug, and the other end is fixedly connected to the circulation pump. Both the upper and lower ends of the lower protective ring are connected to the upper sleeve head and the lower sleeve head by vertical bolts.

[0009] As a further embodiment of the present invention, the lower casing head and the upper casing head are connected by multiple sets of vertical bolts, and side branch pipes are fixedly installed on both sides of the lower casing head and the upper casing head. Sealing valves are fixedly installed on the side branch pipes. A lower connecting plate is fixedly installed at the lower end of the lower casing head, and multiple sets of shock absorbers are provided between the lower connecting plate and the wellhead casing string.

[0010] As a further embodiment of the present invention, a fixing member is fixedly installed on the outer side of the upper end of the upper sleeve head corresponding to the position of the vertical bolt. An L-shaped bracket is rotatably installed on the fixing member. Locking nuts are provided on both sides of the end of the L-shaped bracket away from the fixing member. A limiting rod is provided between the locking nuts. The limiting rod can pass through the threaded sleeve on the vertical bolt. A side bolt is threadedly connected to the L-shaped bracket. The side bolt can be fixedly installed into the installation joint from the side.

[0011] As a further embodiment of the present invention, a temperature sensor and a control component are fixedly installed on the outer side of the upper sleeve head. The temperature sensor can detect the temperature of the external environment, and the control component can adjust the antifreeze temperature according to the temperature sensed by the temperature sensor.

[0012] As a further embodiment of the present invention, a sealing block is provided on the outer side of the connection between the connecting pipe and the upper sleeve head and the lower sleeve head, and a metal protective sleeve is wrapped around the outer side of the connecting pipe.

[0013] Compared with the prior art, the beneficial effects of the present invention are:

[0014] 1. In this invention, a filler is installed at the connection gap between the lower sleeve head and the upper sleeve head, and between the upper sleeve head and the mounting joint. Antifreeze liquid is injected into the filler by a circulating pump, causing the filler to expand. The expanded filler seals the connection gap. Since the filler is expanded by liquid injection to fill the connection gap, any minor misalignment caused by the filler itself can be compensated by the expansion of the liquid injection. This eliminates the possibility of oil leakage caused by misalignment of the sealing gasket after long-term use, increases the service life of the device, and provides fault tolerance for sealing at the sleeve joint connection.

[0015] 2. In this invention, the condenser can adjust the temperature of the antifreeze. Especially in winter, when the brittleness of the upper and lower sleeve joints increases, the antifreeze must be introduced to increase the temperature at the connection between the lower and upper sleeve joints, reducing the possibility of the bolts and sleeve joints breaking due to low-temperature stress, and increasing the strength of the equipment in low-temperature environments. The circulating pump can guide the antifreeze back into the condenser for reheating, so that the antifreeze in the filling component is always at a suitable temperature, and also prevents the antifreeze in the filling component from solidifying and losing its sealing ability. Attached Figure Description

[0016] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the front view structure of the present invention; Figure 2 For the present invention Figure 1 A partial structural diagram at point A in the middle;

[0018] Figure 3 This is a schematic diagram of the rear view structure of the present invention;

[0019] Figure 4 This is a cross-sectional view of the structure of the present invention;

[0020] Figure 5 This is a schematic diagram of the connection structure between the mounting connector and the upper sleeve head in this invention;

[0021] Figure 6 This is a schematic diagram of the connection structure between the lower sleeve head and the upper sleeve head in this invention.

[0022] In the attached diagram, the components represented by each number are as follows: 1. Lower connecting plate; 2. Shock absorber; 3. Lower sleeve head; 4. Upper sleeve head; 5. Side branch pipe; 6. Sealing valve; 7. Mounting joint; 8. Fastener; 9. Side bolt; 10. Vertical bolt; 11. L-shaped bracket; 12. Limiting rod; 13. Locking nut; 14. Circulation pump; 15. Connecting pipe; 16. Lower filler plug; 17. Lower protective ring; 18. Upper protective ring; 19. Antifreeze tank; 20. Inner filler plug; 21. Elastic inner layer. Detailed Implementation

[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] Please see Figures 1 to 6 The present invention provides a technical solution: a casing head for preventing leakage at the wellhead of an oilfield, including a lower casing head 3 and an upper casing head 4, the lower ends of the lower casing head 3 and the upper casing head 4 are connected, the upper end of the upper casing head 4 is connected to an installation joint 7, and built-in seals are provided at the connection between the lower casing head 3 and the upper casing head 4 and at the connection between the upper casing head 4 and the installation joint 7. The built-in seals include: a circulation pump 14, which is fixedly installed on the outside of the upper casing head 4 and is connected to the condenser through an external hose;

[0025] The filler is filled with antifreeze and a connecting pipe 15 is fixedly installed on each filler. The other end of the connecting pipe 15 is fixedly connected to the circulation pump 14. The circulation pump 14 can drive the antifreeze to circulate between the filler and the condenser. The outer surface of the filler is elastic.

[0026] During operation, in this invention, a filler is placed at the connection gap between the lower sleeve head 3 and the upper sleeve head 4, and between the upper sleeve head 4 and the mounting joint 7. Antifreeze liquid is injected into the filler by the circulating pump 14. The antifreeze liquid causes the filler to expand, and the expanded filler seals the connection gap. Since the filler is expanded by liquid injection to fill the connection gap, any minor misalignment caused by the filler itself can be compensated by the expansion of the liquid injection. This eliminates the possibility of oil leakage caused by misalignment of the sealing gasket after long-term use, increases the service life of the device, and provides fault tolerance for sealing at the sleeve joint connection. The condenser can adjust the temperature of the antifreeze, especially in winter when the brittleness of the upper and lower sleeve joints increases. Antifreeze needs to be introduced to increase the temperature at the connection between the upper and lower sleeve joints, reducing the possibility of the bolts and sleeves breaking due to low temperature stress, and increasing the strength of the equipment in low-temperature environments. The circulation pump 14 can guide the antifreeze back into the condenser for reheating, so that the antifreeze in the filling element is always at a suitable temperature, and also prevents the antifreeze in the filling element from solidifying and losing its sealing ability.

[0027] As a further embodiment of the present invention, the filler includes a lower filler plug 16 and an inner filler plug 20. The lower filler plug 16 is an annular rubber plug with a hollow interior. Two sets of lower filler plugs 16 are stacked on top of each other at the connection between the lower sleeve head 3 and the upper sleeve head 4. A lower protective ring 17 is provided on the inner wall between the lower sleeve head 3 and the upper sleeve head 4. The lower filler plug 16 is wrapped between the inner wall of the lower sleeve head 3 and the lower protective ring 17.

[0028] During operation, antifreeze is injected into the lower filling plug 16 of this invention, and the lower protective ring 17 is set inside the lower filling plug 16, enclosing the lower filling plug 16 inside the metal shell to prevent damage to the lower filling plug 16 from external forces such as gravel.

[0029] As a further embodiment of the present invention, the inner filling plug 20 is an annular part with a hollow interior and an opening at the lower end. The side of the inner filling plug 20 near the inner wall of the lower sleeve head 3 is provided with an elastic inner layer 21. An upper protective ring 18 is fixedly installed on the inner side of the upper sleeve head 4. The upper protective ring 18 wraps the inner filling plug 20 inside. An antifreeze groove 19 is opened at the upper end of the upper sleeve head 4. The lower opening of the inner filling plug 20 is embedded in the antifreeze groove 19.

[0030] During operation, antifreeze is injected into the antifreeze tank 19 of this invention. After the antifreeze accumulates, it overflows into the inner filling plug 20 through the lower opening of the inner filling plug 20. As the amount of antifreeze increases, the elastic inner layer 21 on one side of the inner filling plug 20 expands. The expansion of the elastic inner layer 21 increases the sealing of the connection gap between the upper sleeve head 4 and the mounting joint 7.

[0031] As a further embodiment of the present invention, the upper connecting pipe 15 is connected to the antifreeze tank 19, and the lower end is connected to the circulation pump 14. One end of the lower connecting pipe 15 is connected to the hollow lower filling plug 16, and the other end is fixedly connected to the circulation pump 14. The upper and lower ends of the lower protective ring 17 are connected to the upper sleeve head 4 and the lower sleeve head 3 by vertical bolts 10.

[0032] During operation, the circulating pump 14 of the present invention discharges antifreeze liquid into the inner filling plug 20 and the lower filling plug 16 through the connecting pipe 15, and the inner filling plug 20 and the lower filling plug 16 expand to act as a sealing strip for the connection gap.

[0033] As a further embodiment of the present invention, the lower casing head 3 and the upper casing head 4 are connected by multiple sets of vertical bolts 10. Side branch pipes 5 are fixedly installed on both sides of the lower casing head 3 and the upper casing head 4. Sealing valves 6 are fixedly installed on the side branch pipes 5. A lower connecting plate 1 is fixedly installed at the lower end of the lower casing head 3. Multiple sets of shock absorbers 2 are provided between the lower connecting plate 1 and the wellhead casing string.

[0034] During operation, the present invention reduces the vibration experienced by the lower casing head 3 and the upper casing 4 during oil well operation by using the shock absorber 2, thereby reducing the relative movement between the upper casing head 4 and the lower casing head 3.

[0035] As a further embodiment of the present invention, a fixing member 8 is fixedly installed on the outer side of the upper end of the upper sleeve head 4 at the position corresponding to the vertical bolt 10. An L-shaped bracket 11 is rotatably installed on the fixing member 8. Locking nuts 13 are provided on both sides of the end of the L-shaped bracket 11 away from the fixing member 8. A limiting rod 12 is provided between the locking nuts 13. The limiting rod 12 can pass through the threaded sleeve on the vertical bolt 10. A side bolt 9 is threadedly connected to the L-shaped bracket 11. The side bolt 9 can be fixedly installed into the installation joint 7 from the side.

[0036] During operation, the installation connector 7 in this invention serves as the connection end for the blowout preventer, tubing head, and Christmas tree. After the installation connector 7 is connected to the upper casing head 4, the L-shaped bracket 11 on the edge of the upper casing head 4 is rotated and engaged with both sides of the vertical bolt 10. The limiting rod 12 passes through the threaded nut to fix both ends of the vertical bolt 10 to the L-shaped bracket 11. The side bolt 9 fixes the L-shaped bracket 11 to the side wall of the installation connector 7. The limiting rod restricts the rotation of the threaded nut, increasing the firmness of the connection of the vertical bolt 10 and preventing the vertical bolt 10 from loosening. In addition, the side bolt 9 further limits the relative rotation between the installation connector 7 and the upper casing head 4, further reducing the oscillation misalignment between the installation connector 7 and the upper casing head 4, thereby reducing the wear on the filling plug 20 in the connection gap.

[0037] As a further embodiment of the present invention, a temperature sensor and a control component are fixedly installed on the outer side of the upper sleeve head 4. The temperature sensor can detect the temperature of the external environment, and the control component can adjust the antifreeze temperature according to the temperature sensed by the temperature sensor.

[0038] During operation, the temperature sensor in this invention adjusts the temperature of the antifreeze according to the external temperature to ensure that the inner filler plug 20 and the lower filler plug 16 are always in an expanded state.

[0039] As a further embodiment of the present invention, a sealing block is provided on the outer side of the connection between the connecting pipe 15 and the upper sleeve head 4 and the lower sleeve head 3, and a metal protective sleeve is wrapped around the outer side of the connecting pipe 15.

[0040] During operation, the present invention increases the service life of the connecting pipe 15 by means of a metal protective sleeve.

[0041] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A casing head for preventing leakage at oilfield wellheads, comprising a lower casing head (3) and an upper casing head (4), characterized in that: The lower sleeve head (3) and the upper sleeve head (4) are connected at their lower ends. The upper end of the upper sleeve head (4) is connected to an installation connector (7). The connection between the lower sleeve head (3) and the upper sleeve head (4) and the connection between the upper sleeve head (4) and the installation connector (7) are both provided with built-in seals. The built-in seals include: a circulation pump (14). The circulation pump (14) is fixedly installed on the outside of the upper sleeve head (4). The circulation pump (14) is connected to the condenser through an external hose. A filler is filled with antifreeze. A connecting pipe (15) is fixedly installed on the filler. The other end of the connecting pipe (15) is fixedly connected to the circulation pump (14). The circulation pump (14) can drive the antifreeze to circulate between the filler and the condenser. The outer surface of the filler is elastic. The filler includes a lower filler plug (16) and an inner filler plug (20). The lower filler plug (16) is an annular rubber plug with a hollow interior. Two sets of the lower filler plug (16) are stacked on top of each other at the connection between the lower sleeve head (3) and the upper sleeve head (4). A lower protective ring (17) is provided on the inner wall between the lower sleeve head (3) and the upper sleeve head (4). The lower filler plug (16) is wrapped between the inner wall of the lower sleeve head (3) and the lower protective ring (17). The inner filler plug (20) is a hollow annular part with an opening at the lower end. The inner filler plug (20) is provided with an elastic inner layer (21) on the side near the inner wall of the upper sleeve head (4). An upper protective ring (18) is fixedly installed on the inner side of the upper sleeve head (4). The upper protective ring (18) wraps the inner filler plug (20) inside. An antifreeze groove (19) is opened at the upper end of the upper sleeve head (4). The lower opening of the inner filler plug (20) is embedded in the antifreeze groove (19).

2. The casing head for preventing leakage at oilfield wellheads according to claim 1, characterized in that: The upper end of the connecting pipe (15) is connected to the antifreeze tank (19), and the lower end is connected to the circulating pump (14). One end of the lower end of the connecting pipe (15) is connected to the hollow lower filling plug (16), and the other end is fixedly connected to the circulating pump (14). The upper and lower ends of the lower protective ring (17) are connected to the upper sleeve head (4) and the lower sleeve head (3) by vertical bolts (10).

3. The casing head for preventing leakage at oilfield wellheads according to claim 2, characterized in that: The lower casing head (3) and the upper casing head (4) are connected by multiple sets of vertical bolts (10). Side branch pipes (5) are fixedly installed on both sides of the lower casing head (3) and the upper casing head (4). Sealing valves (6) are fixedly installed on the side branch pipes (5). A lower connecting plate (1) is fixedly installed at the lower end of the lower casing head (3). Multiple sets of shock absorbers (2) are provided between the lower connecting plate (1) and the wellhead casing string.

4. The casing head for preventing leakage at oilfield wellheads according to claim 3, characterized in that: Fixing members (8) are fixedly installed on the outer side of the upper end of the upper sleeve head (4) corresponding to the position of the vertical bolt (10). An L-shaped bracket (11) is rotatably installed on the fixing member (8). Locking nuts (13) are provided on both sides of the end of the L-shaped bracket (11) away from the fixing member (8). A limiting rod (12) is provided between the locking nuts (13). The limiting rod (12) can pass through the threaded sleeve on the vertical bolt (10). A side bolt (9) is threadedly connected to the L-shaped bracket (11). The side bolt (9) can be fixedly installed into the installation joint (7) from the side.

5. A casing head for preventing leakage at oilfield wellheads according to claim 4, characterized in that: A temperature sensor and a control component are fixedly installed on the outside of the upper sleeve head (4). The temperature sensor can detect the temperature of the external environment, and the control component can adjust the temperature of the antifreeze according to the temperature sensed by the temperature sensor.

6. The casing head for preventing leakage at oilfield wellheads according to claim 5, characterized in that; A sealing block is provided on the outside of the connection between the connecting pipe (15) and the upper sleeve head (4) and the lower sleeve head (3), and a metal protective sleeve is wrapped around the outside of the connecting pipe (15).

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