A dynamic sealing device

Abstract

The application relates to the technical field of oilfield ground injection enhancement, and discloses a dynamic sealing device. The dynamic sealing device comprises a pump body, a sealing cavity, a high-pressure cavity and a sealing pipe. The sealing cavity is fixed in the pump body and used for storing sealing oil; the high-pressure cavity is fixed in the pump body and used for storing high-pressure fluid; and the sealing pipe is connected with the sealing cavity and the high-pressure cavity. The sealing oil and the high-pressure fluid pass through the sealing pipe and form an oil-water contact surface in the sealing pipe, so that the high-pressure fluid is prevented from entering the pump body. Through the scheme, the problems that the sealing device is prone to wear, the sealing cost is high, and the maintenance period is long during the operation of the injection enhancement unit due to high pressure, large displacement and large pressure difference are solved, the structure of the sealing device of the injection enhancement unit is optimized, the sealing cost is reduced, the sealing is reliable, and the sealing is convenient to maintain.

Description

Technical Field

[0001] This invention relates to the field of oilfield surface injection technology, and in particular to a dynamic sealing device. Background Technology

[0002] In oilfield development, water injection plays a crucial role in increasing reservoir pressure and maintaining reservoir energy. However, due to lower injection pressure at the end of the injection process, the water injection volume in injection wells often fails to meet the actual needs of the reservoir, resulting in the problem of "under-injection wells," which reduces oilfield production and development efficiency.

[0003] To address this issue, oilfields currently deploy booster injection units at the end of the water injection system to increase the pressure of water injection into individual wells, thereby addressing under-injection wells, and this has yielded some positive results. However, in actual operation, due to the complex fluid environment inside the booster injection unit, including high pressure, large flow rate, and large pressure differential, the high-pressure fluid can easily damage the sealing devices during long-term operation, causing water to seep into the motor and leading to motor failure, paralyzing the entire unit and severely impacting production progress. Therefore, it is necessary to use safe and robust sealing devices to seal the high-pressure fluid inside the booster injection unit.

[0004] In related technologies, sealing devices mainly fall into three categories: packing seals, mechanical seals, and magnetic seals. Packing seals rely on the tight contact between the packing shaft and the stuffing box to achieve a sealing effect. While their structure is relatively simple, they experience significant wear during equipment operation and require periodic replacement, which is time-consuming, labor-intensive, and increases maintenance costs. Mechanical and magnetic seals, although improving sealing performance and extending maintenance cycles, require extremely high precision in the fit between components, resulting in higher sealing costs.

[0005] Therefore, there is a need for improvements to the sealing devices in existing injection units. Summary of the Invention

[0006] In view of this, the present invention proposes a dynamic sealing device that solves the problems of easy wear of the sealing device, high sealing cost, and long maintenance cycle caused by factors such as high pressure, large displacement and large pressure difference during the operation of the injection unit. The invention optimizes the structure of the sealing device of the injection unit, reduces the sealing cost, and provides reliable sealing and easy maintenance.

[0007] To achieve the above objectives, one aspect of the present invention provides a dynamic sealing device, specifically comprising: Pump body; A sealing cavity, which is fixed inside the pump body, is used to store sealing oil; A high-pressure chamber, fixed inside the pump body, is used to store high-pressure fluid; A sealing tube, which is connected to both the sealing cavity and the high-pressure cavity; The sealing oil and the high-pressure fluid pass through the sealing pipe and form an oil-water contact surface inside it to prevent the high-pressure fluid from entering the pump body.

[0008] In some embodiments, the dynamic sealing device further includes a sensor fixed to the bottom of the sealing cavity for monitoring the water content in the sealing cavity, so as to adjust the pressure of the high-pressure fluid or replenish the sealing oil according to the water content indication.

[0009] In some embodiments, the dynamic sealing device further includes a rotating component disposed within the pump body for adjusting the pressure of the high-pressure fluid in the high-pressure chamber.

[0010] In some embodiments, the rotating component further includes a motor, which is threaded to the top of the pump body.

[0011] In some embodiments, the rotating component further includes a pump rod, one end of which is connected to the bottom of the motor.

[0012] In some embodiments, the sealing tube includes a first connecting end and a second connecting end, the first connecting end being connected to the high-pressure chamber and the second connecting end being connected to the sealing chamber.

[0013] In some embodiments, the sealing tube includes a spiral sealing tube, which is coiled around the periphery of the pump rod at predetermined intervals.

[0014] In some embodiments, the high-pressure chamber further includes a water inlet that extends outside the pump body and is bolted to the pump body for injecting the high-pressure fluid into the high-pressure chamber.

[0015] In some embodiments, the sealing cavity is embedded and fixed in the middle of the pump body, and the high-pressure cavity is embedded and fixed in the bottom of the pump body.

[0016] In some embodiments, the high-pressure chamber further includes a water outlet, which is connected to an opening at the bottom of the pump body for injecting the high-pressure fluid underground.

[0017] The present invention has at least the following beneficial technical effects: By filling the sealing cavity with sealing oil, the sealing oil and high-pressure fluid achieve dynamic balance in the sealing pipe, thus achieving a sealing effect. This solves the technical problem of poor sealing performance caused by high pressure, large displacement, and large pressure difference during the operation of the injection unit, thereby greatly improving the life and sealing performance of the sealing device. In addition, the sealing cavity and high-pressure cavity are directly and firmly embedded in the pump body structure, effectively preventing displacement of the sealing cavity and high-pressure cavity that may occur during the operation of the injection unit, thus ensuring the long-term stability of the sealing effect. Furthermore, an internal sensor is installed to monitor changes in the water content in the sealing cavity and perform timely maintenance to ensure the sealing effect. In later maintenance, only the sealing oil in the sealing cavity needs to be replenished according to the monitoring results of the sensor, which greatly reduces the sealing cost. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art 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 embodiments can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of an embodiment of the dynamic sealing device provided by the present invention.

[0020] Explanation of reference numerals in the attached figures: 1. Pump body; 2. Sealing chamber; 3. High-pressure chamber; 4. Sealing pipe; 5. Sensor; 6. Motor; 7. Pump rod; 8. Inlet; 9. Outlet. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be further described in detail below with reference to specific examples and the accompanying drawings.

[0022] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention. For example, terms such as “length,” “width,” “upper,” “lower,” “left,” “right,” “front,” “rear,” “vertical,” “horizontal,” “top,” “bottom,” “inner,” and “outer” indicate orientations or positions based on the orientations or positions shown in the accompanying drawings and are for ease of description only, and should not be construed as limiting the technical solution.

[0023] The terms "comprising" and "having," and any variations thereof, used in the specification, claims, and accompanying drawings of this invention are intended to cover non-exclusive inclusion; the terms "first," "second," etc., used in the specification, claims, and accompanying drawings are used to distinguish different objects, not to describe a particular order. "A plurality of" means two or more, unless otherwise explicitly specified.

[0024] In the description and claims of this invention and the foregoing drawings, when an element is referred to as "fixed to," "mounted to," "disposed on," or "connected to" another element, it can be located directly or indirectly on that other element. For example, when an element is referred to as "connected to" another element, it can be directly or indirectly connected to that other element.

[0025] Furthermore, the reference to "embodiment" herein means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of the invention. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0026] Currently, there are various sealing technologies on the market, but for the specific needs of oilfield surface injection equipment (i.e., pressurized water injection equipment), no sealing device has yet been found that can fully meet the long-term stable operation under harsh conditions such as high pressure and large pressure difference.

[0027] For example, Chinese patent application number 202321348233.1, filed on May 30, 2023, discloses a packing seal device for a rotary pump. This patent has a simple structure, low cost, and is easy to install and maintain, and is widely used in piston pumps and centrifugal pumps. However, it is difficult to achieve a completely leak-free packing seal, and the packing wears significantly, requiring regular inspection and maintenance, which is time-consuming and labor-intensive.

[0028] For example, Chinese patent application number 202311093935.4, filed on August 29, 2023, discloses a wear-resistant and corrosion-resistant mechanical seal device for chemical pumps. Compared with packing seals, this patent provides a better sealing effect and a longer maintenance cycle, but its structure is relatively complex, the initial cost is higher, and it requires precise installation and alignment to avoid damage to the sealing surface.

[0029] For example, Chinese patent application number 202020713811.7, filed on April 30, 2020, discloses a magnetic sealing device. Because this patent uses a non-contact sealing method, it experiences almost no wear, reducing maintenance needs and costs, and extending service life. However, compared to packing seals and mechanical seals, this sealing technology has a higher initial cost, requires precise design of the magnetic circuit and magnetic force distribution to ensure a uniform sealing effect, and high-temperature conditions can affect the stability of the magnetic force.

[0030] To address the shortcomings of the existing technology, a safer and more robust sealing device is needed to seal the high-pressure fluid inside the injection unit, ensuring its long-term stable operation and aiding in the management of under-injection wells in oilfields. For example... Figure 1 The diagram shown is a structural schematic of an embodiment of a dynamic sealing device provided by the present invention. The dynamic sealing device includes: a pump body 1; a sealing cavity 2, which is fixed inside the pump body 1 and is used to store sealing oil; a high-pressure cavity 3, which is fixed inside the pump body 1 and is used to store high-pressure fluid; and a sealing pipe 4, which is connected to the sealing cavity 2 and the high-pressure cavity 3 respectively. The sealing oil and the high-pressure fluid form an oil-water contact surface inside the sealing pipe 4 to prevent the high-pressure fluid from entering the pump body 1.

[0031] Furthermore, the sealing cavity 2 is embedded and fixed in the pump body 1, designed as a cavity structure with certain pressure resistance, serving to store sealing oil. Before starting the injection unit, it must be ensured that the sealing cavity 2 is filled with sufficient sealing oil, and that the oil is free of contamination and foreign matter. The high-pressure cavity 3 is embedded and fixed in the pump body 1, designed as a cavity structure with certain pressure resistance, serving to store high-pressure fluid. Before starting the injection unit, it must be ensured that the high-pressure cavity 3 is filled with high-pressure fluid, and that the water pressure reaches the predetermined working pressure. The sealing pipe 4, as a key component connecting the sealing cavity 2 and the high-pressure cavity 3, has one end embedded and fixed in the pump body 1 and connected to the high-pressure cavity 3, and the other end connected to the sealing cavity 2, serving to dynamically balance the pressure of the sealing cavity 2 and the high-pressure cavity 3.

[0032] Furthermore, during the operation of the injection unit, the high-pressure fluid in high-pressure chamber 3 and the sealing oil in sealing chamber 2 come into contact in sealing pipe 4, forming an oil-water contact surface at their contact point. When the pressure of the high-pressure fluid in high-pressure chamber 3 is high, the pressure difference pushes the oil-water contact surface in sealing pipe 4 towards sealing chamber 2 until the pressure in sealing chamber 2 and high-pressure chamber 3 reaches dynamic equilibrium. When the pressure of the high-pressure fluid in high-pressure chamber 3 is low, the pressure difference pushes the oil-water contact surface in sealing pipe 4 towards high-pressure chamber 3 until the pressure in sealing chamber 2 and high-pressure chamber 3 reaches dynamic equilibrium.

[0033] The dynamic sealing device of this invention enables the sealing oil and high-pressure fluid to achieve dynamic balance in the sealing pipe 4, thus achieving a sealing effect. There is no wear of the sealing components during the sealing process, avoiding the problem of sealing failure during long-term operation of the injection unit. The device has a simple structure, is easy to install, has low initial cost, and is structurally stable. The axial force generated during the operation of the injection unit will not cause displacement of the sealing cavity 2 and the high-pressure cavity 3. In later maintenance, only the sealing oil needs to be added to the sealing cavity 2. The sealing cost can be reduced by more than 40% compared with the prior art.

[0034] In some embodiments, the dynamic sealing device of the present invention further includes a sensor 5, which is fixed to the bottom of the sealing cavity 2 and is used to monitor the water content in the sealing cavity 2 so as to adjust the pressure of the high-pressure fluid or replenish the sealing oil according to the water content indication.

[0035] Furthermore, sensor 5 is fixed to the bottom of the sealing cavity 2 to monitor changes in the moisture content of the sealing cavity 2. During the operation of the injection unit, the changes in moisture content monitored by sensor 5 are continuously observed. Based on the monitoring results, the pressure of the high-pressure fluid in the high-pressure cavity 3 is adjusted to maintain the stability of the oil-water contact surface and prevent high-pressure fluid from entering the sealing cavity 2. When an abnormal moisture content is detected, it indicates that high-pressure fluid has entered the sealing cavity 2. To prevent high-pressure fluid from entering the pump body 1 and causing a short circuit that would prevent the unit from operating normally, the injection unit must be stopped immediately. The injection unit should be inspected and maintained regularly based on the changes in moisture content monitored by sensor 5, and sealing oil should be replenished in a timely manner.

[0036] The dynamic sealing device of the present invention is equipped with a sensor 5 to monitor changes in moisture content and perform timely maintenance to ensure sealing effect and extend sealing life by more than 50%.

[0037] In some embodiments, the dynamic sealing device of the present invention further includes a rotating component disposed within the pump body 1 for adjusting the pressure of the high-pressure fluid in the high-pressure chamber 3.

[0038] In some embodiments, the rotating component also includes a motor 6, which is threaded to the top of the pump body 1.

[0039] In some embodiments, the rotating component also includes a pump rod 7, one end of which is connected to the bottom of the motor 6.

[0040] Furthermore, the rotating components must be inspected before starting the injection unit to ensure they are undamaged and well-lubricated. The rotating components continuously rotate during operation to pressurize the high-pressure fluid in the high-pressure chamber. The rotating components include a motor 6 and a pump rod 7 fixedly connected to each other. The motor 6 provides the kinetic energy required for the normal operation of the injection unit, while the pump rod 7 rotates continuously to pressurize the injected fluid. The motor 6 and the pump body 1 are tightly connected and fixed by rotating nuts or bolts. This threaded fixing method has advantages such as simple structure, reliable connection, and easy disassembly.

[0041] The dynamic sealing device of the present invention achieves the pressurization function through a rotating component combining a motor 6 and a pump rod 7. It has a simple structure and is easy to maintain.

[0042] In some embodiments, the sealing tube 4 includes a first connecting end and a second connecting end, the first connecting end being connected to the high-pressure chamber 3 and the second connecting end being connected to the sealing chamber 2.

[0043] In some embodiments, the sealing tube 4 includes a spiral sealing tube, which is coiled around the periphery of the pump rod 7 at predetermined intervals.

[0044] Furthermore, the sealing pipe 4 can be a spiral sealing pipe, which is spirally wound around the pump rod 7 at a certain interval. The top end of the spiral sealing pipe (i.e., the first connecting end) is connected to the high-pressure chamber 3, and the tail end (i.e., the second connecting end) is connected to the sealing chamber 2. Through its spiral inner wall design, dynamic pressure balance is achieved between the sealing chamber 2 and the high-pressure chamber 3. Before starting the injection unit, it is necessary to ensure that there are no foreign objects inside the spiral sealing pipe and no leaks at the connection.

[0045] The dynamic sealing device of the present invention utilizes a spiral sealing structure that achieves a long distance within a limited space to design the sealing pipe, which can effectively prevent fluid leakage and improve the sealing performance of the pipeline.

[0046] In some embodiments, the high-pressure chamber 3 further includes a water inlet 8, which extends out of the pump body 1 and is connected to the pump body 1 by bolts, for injecting high-pressure fluid into the high-pressure chamber 3.

[0047] In some embodiments, the sealing cavity 2 is embedded and fixed in the middle of the pump body 1, and the high-pressure cavity 3 is embedded and fixed in the bottom of the pump body 1.

[0048] In some embodiments, the high-pressure chamber 3 also includes a water outlet 9, which is connected to the bottom opening of the pump body 1 for injecting high-pressure fluid underground.

[0049] Combination Figure 1 The following describes the method of using the device of the present invention, based on the illustrated embodiments.

[0050] Before starting the injection unit, necessary preparations should be made, including: (1) checking the sealing chamber 2 to ensure that the sealing chamber 2 is filled with sufficient sealing oil and that the oil is free from contamination and foreign matter; (2) checking the high pressure chamber 3 to ensure that the high pressure chamber 3 is filled with high pressure fluid and that the water pressure reaches the predetermined working pressure; (3) ensuring that there is no foreign matter in the sealing pipe 4 and that there is no leakage at the connection; (4) checking the rotating parts to ensure that the rotating parts are undamaged and well lubricated.

[0051] When starting the injection unit, observe its operating status to ensure that it operates smoothly without abnormal noise or vibration.

[0052] During the operation of the booster unit, the pressure in the sealing chamber 2 and the high-pressure chamber 3 is observed to determine whether they have reached a dynamic equilibrium state based on the oil-water contact surface in the sealing pipe. The water content changes monitored by sensor 3 are continuously observed. If the water content is abnormal, i.e., water is present in the sealing chamber 2, the booster unit is immediately stopped to prevent high-pressure fluid from entering the sealing chamber 2 and then re-entering the pump body 1, which could then enter the motor 6, causing a short circuit and preventing normal operation of the unit.

[0053] Regularly inspect and maintain the injection unit, and replenish the sealing oil in the sealing cavity 2 in a timely manner.

[0054] The above operating procedures may vary depending on the actual environment, equipment, and injected fluid, and adjustments need to be made according to the specific circumstances.

[0055] The dynamic sealing device of this invention achieves a sealing effect by filling the sealing cavity with sealing oil, which allows the sealing oil and high-pressure fluid to reach a dynamic balance in the sealing pipe. This solves the technical problem of poor sealing effect caused by high pressure, large displacement, and large pressure difference during the operation of the injection unit, thus greatly improving the life and sealing performance of the sealing device. In addition, the sealing cavity and the high-pressure cavity are directly and securely embedded in the pump body structure, effectively preventing displacement of the sealing cavity and the high-pressure cavity that may occur during the operation of the injection unit, thereby ensuring the long-term stability of the sealing effect. Furthermore, an internal sensor is installed to monitor changes in the water content in the sealing cavity and perform timely maintenance to ensure the sealing effect. In later maintenance, only the sealing oil in the sealing cavity needs to be replenished according to the monitoring results of the sensor, which greatly reduces the sealing cost.

[0056] The above are exemplary embodiments disclosed in this invention. However, it should be noted that various changes and modifications can be made without departing from the scope of the embodiments of this invention as defined by the claims. The functions, steps, and / or actions of the methods according to the disclosed embodiments described herein do not need to be performed in any particular order. Furthermore, although the elements disclosed in the embodiments of this invention may be described or claimed individually, they may be understood as multiple unless explicitly limited to a singular number.

[0057] It should be understood that, as used herein, the singular form “a” is intended to include the plural form as well, unless the context clearly supports an exception. It should also be understood that, as used herein, “and / or” refers to any and all possible combinations of one or more of the associated listed items.

[0058] The embodiment numbers disclosed in the above embodiments of the present invention are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0059] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of the invention (including the claims) is limited to these examples. Within the framework of the invention, technical features of the above embodiments or different embodiments can be combined, and many other variations of different aspects of the invention exist, which are not provided in the details for the sake of brevity. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the invention should be included within the protection scope of the invention.

Claims

1. A dynamic sealing device, characterized in that, include: Pump body; A sealing cavity, which is fixed inside the pump body, is used to store sealing oil; A high-pressure chamber, which is fixed inside the pump body, is used to store high-pressure fluid; A sealing tube, which is connected to both the sealing cavity and the high-pressure cavity; The sealing oil and the high-pressure fluid pass through the sealing pipe and form an oil-water contact surface inside it to prevent the high-pressure fluid from entering the pump body.

2. The dynamic sealing device according to claim 1, characterized in that, It also includes a sensor fixed to the bottom of the sealing cavity for monitoring the water content in the sealing cavity, so as to adjust the pressure of the high-pressure fluid or replenish the sealing oil according to the water content indication.

3. The dynamic sealing device according to claim 2, characterized in that, It also includes a rotating component, which is disposed inside the pump body and is used to adjust the pressure of the high-pressure fluid in the high-pressure chamber.

4. The dynamic sealing device according to claim 3, characterized in that, The rotating component also includes a motor, which is threaded to the top of the pump body.

5. The dynamic sealing device according to claim 4, characterized in that, The rotating component also includes a pump rod, one end of which is connected to the bottom of the motor.

6. The dynamic sealing device according to claim 1, characterized in that, The sealing tube includes a first connecting end and a second connecting end, the first connecting end being connected to the high-pressure chamber and the second connecting end being connected to the sealing chamber.

7. The dynamic sealing device according to claim 5, characterized in that, The sealing tube includes a spiral sealing tube, which is coiled around the periphery of the pump rod at preset intervals.

8. The dynamic sealing device according to claim 1, characterized in that, The high-pressure chamber also includes a water inlet, which extends out of the pump body and is connected to the pump body via bolts, for injecting the high-pressure fluid into the high-pressure chamber.

9. The dynamic sealing device according to claim 1, characterized in that, The sealing cavity is embedded and fixed in the middle of the pump body, and the high-pressure cavity is embedded and fixed in the bottom of the pump body.

10. The dynamic sealing device according to claim 3, characterized in that, The high-pressure chamber also includes a water outlet, which is connected to the bottom opening of the pump body for injecting the high-pressure fluid underground.

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