Secondary sealing oil return device for oil extraction wellhead

Abstract

The utility model discloses a secondary sealing oil return device for an oil extraction wellhead, which is characterized in that a wellhead sealing cylinder is assembled at the upper end of the wellhead, a wellhead liquid accumulation bin is assembled at the upper part of the wellhead sealing cylinder, a wellhead tee joint is sleeved on the wellhead sealing cylinder at the lower part of the wellhead liquid accumulation bin, and the wellhead liquid accumulation bin is communicated with the wellhead tee joint; an oil return pipeline is further communicated between the wellhead liquid accumulation bin and the wellhead tee joint. And a one-way pressure valve is assembled on the oil return pipeline. A sealing rod is inserted into an inner cavity of the well mouth liquid accumulation bin and arranged on the steel wire rope oil pumping polish rod in a sleeving mode, and a sealing packing is assembled on the upper portion of the sealing rod. The utility model has the beneficial effects that the sealing performance of the wellhead is obviously improved, and the leakage of well fluid is effectively prevented. The oil extraction efficiency is improved, the total yield is increased, and the service life of an oil well and equipment can be prolonged. And the production cost and the maintenance cost of oil extraction operation are reduced. And potential safety hazards are reduced.

Description

Technical Field

[0001] The utility model relates to a sealing oil return device, in particular to a secondary sealing oil return device for an oil production wellhead. Background Art

[0002] In the current oilfield development practice, the mechanical oil production method with rod pumps occupies a dominant position, accounting for more than 98% of the total number of wells in the oilfield. This type of oil production system generally relies on pumping rods (including rigid and flexible designs) as key components connecting ground equipment and downhole pumping rods, and the performance of the oil production wellhead rod sealer is directly related to the sealing effect of the wellhead. In particular, the ultra-long stroke pumping unit technology disclosed in Patent No. 202021452462.4, by introducing flexible wire rope pumping rods and innovative wellhead sealing devices, realizes the creative application of wire rope structural characteristics, and effectively solves the limitations of traditional wire rope pumping rods in breaking tension, safety risks and wellhead sealing life.

[0003] However, although the above technologies have improved oil production efficiency and safety to a certain extent, the dynamic mobile seal still faces severe challenges in terms of sealing effect. Due to the long stroke and low stroke characteristics of oil production operations, as well as the complex and changeable well conditions, the continuous wear of the sealing plunger will lead to a sharp decline in sealing effect, sealing reliability and sealing performance, which will in turn cause serious consequences such as well fluid leakage, reduced oil extraction efficiency and even blowouts, directly increasing production costs, aggravating the difficulty of on-site operations, and threatening operational safety. Summary of the invention

[0004] The main purpose of the utility model is to solve the problems that the sealing plunger used in the existing oil field exploitation operation will be constantly worn, resulting in a sharp decline in sealing effect, sealing reliability and sealing performance, which will further cause serious consequences such as well fluid leakage, reduced oil pumping efficiency and even blowout, directly increase production costs, aggravate the difficulty of on-site operation, and threaten the safety of operations. A secondary sealing oil return device for an oil wellhead is provided to solve the problems that the sealing plunger used in the existing oil field exploitation operation will be constantly worn, resulting in a sharp decline in sealing effect, sealing reliability and sealing performance, which will further cause serious consequences such as well fluid leakage, reduced oil pumping efficiency and even blowout, directly increase production costs, aggravate the difficulty of on-site operation, and threaten the safety of operations.

[0005] The utility model provides an oil production wellhead secondary sealing oil return device, in which a wellhead sealing cylinder is mounted at the upper end of the wellhead, a wellhead liquid storage bin is mounted on the upper part of the wellhead sealing cylinder, a wellhead tee is sleeved on the wellhead sealing cylinder at the lower part of the wellhead liquid storage bin, the wellhead liquid storage bin is connected with the wellhead tee, and an oil return pipeline is also connected between the wellhead liquid storage bin and the wellhead tee.

[0006] A one-way pressure valve is installed on the oil return pipeline.

[0007] A sealing rod is inserted into the inner cavity of the wellhead liquid storage bin, the sealing rod is sleeved on the wire rope oil pumping polished rod, and a sealing packing is assembled on the upper part of the sealing rod.

[0008] The sealing packing includes a packing upper end cover, a rubber gland, a sealing ring, a packing shell and a rubber base, wherein the sealing ring is provided with several tracks which are sequentially inserted into the inner cavity of the packing shell, the rubber gland is assembled on the top of the uppermost sealing ring, the packing upper end cover is assembled on the top of the rubber gland and the packing shell, the rubber base is assembled on the bottom of the lowermost sealing ring, and the sealing packing is connected to the top of the wellhead liquid storage tank through a flange.

[0009] The top of the wellhead sealing cylinder is assembled in the wellhead tee through the sealing cylinder hanger, the lower part of the wellhead sealing cylinder is connected to the oil well pipe, and the connection between the wellhead sealing cylinder and the oil well pipe is equipped with a wellhead four-way, the wellhead four-way and the wellhead tee are connected, and the top of the oil well pipe is assembled in the wellhead four-way through the oil pipe hanger.

[0010] A sealing plunger is also installed in the inner cavity at the lower part of the wellhead sealing cylinder. The top of the sealing plunger is connected to the bottom of the sealing rod through a cable joint, and the bottom of the sealing plunger is connected to the top of the sucker rod in the oil well pipe.

[0011] The one-way pressure valve, sealing cylinder hanger and oil pipe hanger mentioned above are all assemblies of existing equipment, so the specific models and specifications are not described in detail.

[0012] The working principle of this utility model:

[0013] The secondary sealing oil return device for the oil production wellhead provided by the utility model is divided into three sections: upper, middle and lower, which are the wellhead liquid storage bin, the wellhead tee and the wellhead four-way, respectively. An oil return pipeline equipped with a one-way pressure valve is connected between the wellhead liquid storage bin and the wellhead tee to achieve directional reflux of the well fluid. A sealing rod and a sealing packing are installed on the top of the wellhead liquid storage bin to form the first key sealing barrier. A sealing cylinder hanger is installed in the wellhead tee, and an oil pipe hanger is installed in the wellhead four-way. The sealing cylinder hanger and the oil pipe hanger are used to fix the wellhead sealing cylinder and the oil well pipe respectively to ensure that they are firmly connected and the oil circuit is unobstructed.

[0014] The lower part of the inner cavity of the wellhead sealing cylinder is equipped with a sealing plunger. The sealing plunger is characterized by a small gap between it and the wellhead sealing cylinder. It operates flexibly and constitutes the first key sealing barrier. The bottom of the sealing plunger is connected to the sucker rod, and the top of the sealing plunger is connected to the bottom of the sealing rod through a cable joint. The upper part of the sealing rod is covered with a sealing packing to form a tight fit, effectively preventing blowout accidents. At the same time, the wire rope pumping rod is inserted into the sealing rod, and its two ends are respectively connected to the cable joint and the well drive mechanism to realize power transmission and motion control.

[0015] During the operation, the driving mechanism on the well drives the wire rope pumping rod, driving the sealing plunger to reciprocate up and down in the wellhead sealing cylinder. During the downstroke, the well fluid is pumped into the annular oil channel between the oil well pipe and the wellhead sealing cylinder, and collected through the wellhead tee. Due to the gap between the sealing plunger and the wellhead sealing cylinder, some well fluid will enter the wellhead liquid storage tank, but under the double sealing effect of the sealing rod and the sealing packing, the area remains closed and the well fluid cannot leak out.

[0016] As the sealing plunger continues to reciprocate, the gas-liquid pressure in the wellhead liquid storage tank gradually accumulates, forming a positive pressure environment. When the pressure reaches the set threshold, the one-way pressure valve installed on the oil return pipeline between the wellhead liquid storage tank and the wellhead tee automatically opens to allow the well fluid in the wellhead liquid storage tank to flow back through the oil return pipeline to the annular oil channel between the oil well pipe and the wellhead sealing cylinder. In this process, the reciprocating motion of the sealing plunger synchronously controls the opening and closing of the one-way pressure valve, ensuring the effective use of the oil return pipeline and the immediate recovery of the sealing state, thereby successfully completing the sealing and oil return tasks of the oil production wellhead.

[0017] Beneficial effects of the utility model:

[0018] The secondary sealing oil return device for the oil production wellhead provided by the utility model has the following beneficial effects:

[0019] 1. Double sealing protection: The precise cooperation between the sealing plunger and the wellhead sealing cylinder as well as the sealing packing and the sealing rod jointly constructs a double sealing barrier, which significantly improves the sealing performance of the wellhead and effectively prevents the occurrence of well fluid leakage.

[0020] 2. Improve oil recovery efficiency: The optimized oil return mechanism reduces the interference of well fluid on oil recovery operations, improves oil recovery efficiency and increases total production.

[0021] 3. Extend the life of oil wells: Reduce the corrosion and wear of well fluid on oil wells and equipment, which helps to extend the service life of oil wells and equipment.

[0022] 4. Reduce production costs: By reducing well fluid leakage and equipment damage, the production cost and maintenance expenses of oil production operations are reduced.

[0023] 5. Enhanced operation safety: The strict double sealing design and reliable oil return mechanism significantly improve the safety of oil production operations and reduce potential safety hazards. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic cross-sectional view of the overall structure of the wellhead secondary sealing oil return device described in the utility model.

[0025] Figure 2 It is a schematic diagram of the cross-sectional structure of the sealing packing described in the utility model.

[0026] The annotations in the above figure are as follows:

[0027] 1. Wellhead sealing cylinder 2. Wellhead liquid storage tank 3. Wellhead tee 4. Oil return pipeline

[0028] 5. One-way pressure valve 6. Sealing rod 7. Wire rope oil pumping rod 8. Sealing packing

[0029] 9. Packing upper end cover 10. Rubber gland 11. Sealing ring 12. Packing shell

[0030] 13. Rubber base 14. Flange 15. Sealing cylinder hanger 16. Oil well pipe

[0031] 17. Wellhead spool 18. Tubing hanger 19. Sealing plunger 20. Cable socket

[0032] 21. Sucker rod. DETAILED DESCRIPTION

[0033] See also Figure 1 to Figure 2 As shown:

[0034] The utility model provides an oil production wellhead secondary sealing and oil return device, in which a wellhead sealing cylinder 1 is mounted at the upper end of the wellhead, a wellhead liquid storage bin 2 is mounted on the upper part of the wellhead sealing cylinder 1, a wellhead tee 3 is sleeved on the wellhead sealing cylinder 1 at the lower part of the wellhead liquid storage bin 2, the wellhead liquid storage bin 2 is connected with the wellhead tee 3, and an oil return pipeline 4 is also connected between the wellhead liquid storage bin 2 and the wellhead tee 3.

[0035] A one-way pressure valve 5 is installed on the oil return pipeline 4.

[0036] A sealing rod 6 is inserted into the inner cavity of the wellhead liquid storage bin 2 . The sealing rod 6 is sleeved on a wire rope oil pumping polished rod 7 . A sealing packing 8 is assembled on the upper part of the sealing rod 6 .

[0037] The sealing packing 8 includes a packing upper end cover 9, a rubber gland 10, a sealing ring 11, a packing shell 12 and a rubber base 13, wherein the sealing ring 11 is provided with several channels which are sequentially inserted into the inner cavity of the packing shell 12, the rubber gland 10 is assembled on the top of the uppermost sealing ring 11, the packing upper end cover 9 is assembled on the top of the rubber gland 10 and the packing shell 12, the rubber base 13 is assembled on the bottom of the lowermost sealing ring 11, and the sealing packing 8 is connected to the top of the wellhead liquid storage tank 2 through a flange 14.

[0038] The top of the wellhead sealing cylinder 1 is assembled in the wellhead tee 3 through the sealing cylinder hanger 15, the lower part of the wellhead sealing cylinder 1 is connected to the oil well pipe 16, and the connection between the wellhead sealing cylinder 1 and the oil well pipe 16 is equipped with a wellhead four-way 17, the wellhead four-way 17 is connected to the wellhead tee 3, and the top of the oil well pipe 16 is assembled in the wellhead four-way 17 through the oil pipe hanger 18.

[0039] A sealing plunger 19 is also installed in the inner cavity at the lower part of the wellhead sealing cylinder 1. The top of the sealing plunger 19 is connected to the bottom of the sealing rod 6 through a cable joint 20, and the bottom of the sealing plunger 19 is connected to the top of the sucker rod 21 in the oil well pipe 16.

[0040] The one-way pressure valve 5, the sealing cylinder hanger 15 and the oil pipe hanger 18 are all assemblies of existing equipment, so the specific models and specifications are not described in detail.

[0041] The working principle of this utility model:

[0042] The secondary sealing oil return device for the oil production wellhead provided by the utility model is divided into three sections: upper, middle and lower, which are the wellhead liquid storage tank 2, the wellhead tee 3 and the wellhead four-way 17 respectively. A return oil pipeline 4 equipped with a one-way pressure valve 5 is connected between the wellhead liquid storage tank 2 and the wellhead tee 3 to achieve directional reflux of the well fluid. A sealing rod 6 and a sealing packing 8 are installed on the top of the wellhead liquid storage tank 2 to form the first key sealing barrier. A sealing cylinder hanger 15 is installed in the wellhead tee 3, and an oil pipe hanger 18 is installed in the wellhead four-way 17. The sealing cylinder hanger 15 and the oil pipe hanger 18 are used to fix the wellhead sealing cylinder 1 and the oil well pipe 16 respectively to ensure that they are firmly connected to each other and the oil circuit is unobstructed.

[0043] The lower part of the inner cavity of the wellhead sealing cylinder 1 is equipped with a sealing plunger 19. The sealing plunger 19 is characterized by a small gap between it and the wellhead sealing cylinder 1, and operates flexibly, forming the first key sealing barrier. The bottom of the sealing plunger 19 is connected to the sucker rod 21, and the top of the sealing plunger 19 is connected to the bottom of the sealing rod 6 through the cable joint 20. The upper part of the sealing rod 6 is sleeved with a sealing packing 8 to form a tight fit, effectively preventing blowout accidents. At the same time, the wire rope pumping rod 7 is inserted into the sealing rod 6, and its two ends are respectively connected to the cable joint 20 and the well drive mechanism to realize power transmission and motion control.

[0044] During the operation, the driving mechanism on the well drives the wire rope pumping rod 7, driving the sealing plunger 19 to reciprocate up and down in the wellhead sealing cylinder 1. During the downstroke, the well fluid is pumped into the annular oil channel between the oil well pipe 16 and the wellhead sealing cylinder 1, and is collected through the wellhead tee 3. Due to the gap between the sealing plunger 19 and the wellhead sealing cylinder 1, part of the well fluid will enter the wellhead liquid storage tank 2, but under the double sealing effect of the sealing rod 6 and the sealing packing 8, this area remains closed and the well fluid cannot leak out.

[0045] As the sealing plunger 19 continues to reciprocate, the gas-liquid pressure in the wellhead liquid storage tank 2 gradually accumulates, forming a positive pressure environment. When the pressure reaches the set threshold, the one-way pressure valve 5 installed on the oil return pipeline 4 between the wellhead liquid storage tank 2 and the wellhead tee 3 automatically opens to allow the well fluid in the wellhead liquid storage tank 2 to flow back through the oil return pipeline 4 to the annular oil channel between the oil well pipe 16 and the wellhead sealing cylinder 1. In this process, the reciprocating motion of the sealing plunger 19 synchronously controls the opening and closing of the one-way pressure valve 5, ensuring the effective use of the oil return pipeline 4 and the immediate recovery of the sealing state, thereby successfully completing the sealing and oil return tasks of the oil production wellhead.

Claims

1. A secondary sealing oil return device for an oil production wellhead, characterized in that: A wellhead sealing cylinder is installed at the upper end of the wellhead, a wellhead liquid storage tank is installed on the upper part of the wellhead sealing cylinder, a wellhead tee is sleeved on the wellhead sealing cylinder at the lower part of the wellhead liquid storage tank, the wellhead liquid storage tank is connected with the wellhead tee, and an oil return pipeline is also connected between the wellhead liquid storage tank and the wellhead tee.

2. The secondary sealing oil return device for an oil production wellhead according to claim 1, characterized in that: The oil return pipeline is equipped with a one-way pressure valve.

3. The secondary sealing oil return device for an oil production wellhead according to claim 1, characterized in that: A sealing rod is inserted into the inner cavity of the wellhead liquid storage bin, the sealing rod is sleeved on the wire rope oil pumping polished rod, and a sealing packing is assembled on the upper part of the sealing rod.

4. The secondary sealing oil return device for an oil production wellhead according to claim 3, characterized in that: The sealing packing includes a packing upper end cover, a rubber gland, a sealing ring, a packing shell and a rubber base, wherein the sealing ring is provided with several tracks which are sequentially inserted into the inner cavity of the packing shell, the rubber gland is assembled on the top of the uppermost sealing ring, the packing upper end cover is assembled on the top of the rubber gland and the packing shell, the rubber base is assembled on the bottom of the lowermost sealing ring, and the sealing packing is connected to the top of the wellhead liquid storage tank through a flange.

5. The secondary sealing oil return device for an oil production wellhead according to claim 1, characterized in that: The top of the wellhead sealing cylinder is assembled in the wellhead tee through the sealing cylinder hanger, the lower part of the wellhead sealing cylinder is connected to the oil well pipe, the connection between the wellhead sealing cylinder and the oil well pipe is equipped with a wellhead four-way, the wellhead four-way and the wellhead tee are connected, and the top of the oil well pipe is assembled in the wellhead four-way through the oil pipe hanger.

6. The secondary sealing oil return device for an oil production wellhead according to claim 1 or 5, characterized in that: A sealing plunger is also installed in the inner cavity at the lower part of the wellhead sealing cylinder. The top of the sealing plunger is connected to the bottom of the sealing rod through a cable joint, and the bottom of the sealing plunger is connected to the top of the sucker rod in the oil well pipe.

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