A booster water injection screw pump and a control system containing the booster water injection screw pump
By introducing a high-pressure rotary dynamic seal and control system into the pressurized water injection device, the problem of motor seal leakage was solved, resulting in a long motor life and stable water injection process, while reducing maintenance costs.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- XINXIANG XIAFENG ELECTRIC LTC
- Filing Date
- 2025-07-10
- Publication Date
- 2026-07-31
AI Technical Summary
In traditional booster water injection devices, the motor sealing device is prone to leakage, which can lead to water ingress into the motor, affecting the continuity and long-term reliability of the water injection process. In addition, the maintenance cost is high and it cannot adapt to the development progress and internal conditions of different oil wells.
A high-pressure rotary dynamic sealing device is adopted, including a dynamic sealing ring, end cover, sealing tube, flexible pressure transmission body, first shaft seal, second shaft seal, isolation sleeve and shell, forming a long-term sealed liquid channel. Combined with a pressure relief device and control system, it prevents high-pressure water from entering the motor and adjusts the motor speed through the controller to stabilize the water injection pressure.
It effectively prevents high-pressure water from seeping into the motor, extends the motor's service life, reduces maintenance costs, improves the stability and adaptability of the water injection process, and reduces maintenance frequency.
Smart Images
Figure CN224579469U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to an oil well booster water injection device and a control system containing the device, specifically to a booster water injection screw pump and a control system containing the booster water injection screw pump. Background Technology
[0002] At oil well development sites, as extraction time increases, the energy of the oil reservoir is continuously consumed, and the internal pressure drops significantly. As the pressure decreases, the underground crude oil undergoes significant degassing, leading to increased viscosity and ultimately a sharp decline in well production. This eventually results in the cessation of oil injection and production shutdown, leaving a large amount of unrecoverable crude oil and wasting resources. The traditional solution is to inject high-pressure water into the well. However, to save costs, a single water injection system is often used to inject water into multiple wells simultaneously. This introduces new problems: because the development progress and internal conditions of each well differ, some wells may not receive sufficient water pressure to achieve the desired effect. This necessitates targeted pressurization water injection based on the specific conditions of each well. The continuous increase in pressure can cause slow leakage in the motor seals of the screw pump, allowing water to enter the motor and severely affecting the continuity and long-term reliability of the water injection process. Sometimes, excessive pressure can cause the motor to burn out after only about two weeks of operation. Furthermore, frequent replacement of the motor system leads to interruptions in the extraction process and a significant increase in maintenance costs. For example, the pressure balancing device used in the sealing chamber of a novel screw pump booster water injection device disclosed in application publication number CN109139455A, while significantly increasing the motor's resistance to damage under excessive pressure as the pressure increases, only maintains long-term reliability for about six months. Similarly, the motor's mechanical seal slowly leaks, leading to water ingress. Currently, there is an urgent need for a longer-life design to achieve a longer service life, easier maintenance, and further reduce oil production costs with a more adaptable booster water injection device. Summary of the Invention
[0003] To address the aforementioned technical issues of water inlet in screw pump motors, increasing the long-term reliability of pressurized water injection, and further reducing the cost of water injection during oil production, this utility model provides a booster water injection screw pump, comprising a motor, a high-pressure rotary dynamic seal, a flexible connector, a screw pump, an inlet, and an outlet. The high-pressure rotary dynamic seal is mounted on the motor shaft of the motor. The flexible connector connects the motor shaft to the screw pump. The inlet connects the inner cavity of the booster water injection screw pump to an external water supply pipe. The outlet discharges the high-pressure water pressurized by the screw pump. The high-pressure rotary dynamic seal includes a dynamic sealing ring, an end cap, a sealing tube, a flexible pressure transmitting body, a vent hole, a first shaft seal, a second shaft seal, an isolation sleeve, a housing, and a drain port. The dynamic sealing ring, end cap, sealing tube, and isolation sleeve extend along the motor shaft away from the motor end towards... The motor is gradually fitted onto the motor shaft and sealed with the housing. A relatively sealed space is formed between the sealing tube and the motor shaft. The flexible pressure transmission body is fitted outside the sealing tube. A channel communicating with the interior of the flexible pressure transmission body is provided on the sealing tube. The second shaft seal is provided between the sealing tube and the motor shaft near the end cover to prevent high-pressure water from entering the interior of the sealing tube. The first shaft seal is provided near the motor to prevent liquid inside the sealing tube from entering the motor. The vent hole connects the high-pressure rotary dynamic seal to the external space through the housing. A channel is provided on the end cover to connect the high-pressure water inside the screw pump with the cavity formed between the exterior of the flexible pressure transmission body and the housing. The high-pressure rotary dynamic seal also includes a long-lasting sealed liquid channel for high-pressure water to pass through and prevent it from entering the interior of the motor.
[0004] Through the structural design of this utility model, especially the addition of a long-lasting sealed liquid channel, high-pressure water can be effectively prevented from rapidly penetrating through the rotary seal and entering the motor, further extending the service life of the motor and reducing the use and maintenance costs of the equipment.
[0005] Furthermore, the long-lasting sealed liquid channel includes a channel on the end cover connecting the high-pressure water chamber inside the screw pump and the cavity formed between the flexible pressure transmission body and the housing, a sealing surface between the dynamic sealing ring and the end cover, a space between the sealing tube and the motor shaft, a through hole between the sealing tube and the flexible pressure transmission body, a through hole on the isolation sleeve and a serpentine tube connected to the through hole, a vent hole, a liquid outlet of the serpentine tube, and a liquid discharge port.
[0006] By setting a first shaft seal and a second shaft seal between the sealing tube of the high-pressure rotary dynamic seal and the motor shaft, the water that seeps in can flow through the designed long-term sealed liquid channel and finally be discharged from the rotary dynamic seal through the drain port, effectively reducing the time it takes for the water to enter the motor, thereby further extending its service life and reducing maintenance costs.
[0007] Furthermore, it also includes a channel provided on the end cap, connecting the cavity formed by the housing and the flexible pressure transmission body and the screw pump chamber, and a pressure relief device provided at the connection between the channel and the screw pump chamber.
[0008] During the high-speed rotation of the motor, the various components in the high-pressure rotating dynamic seal rub against each other, generating a large amount of heat. This causes the internal temperature of the high-speed rotating dynamic seal to increase rapidly, further increasing its internal pressure. This not only affects the sealing effect but also increases the risk of accidents. By setting up a pressure relief device, the pressure can be effectively released, ensuring its overall stable operation.
[0009] Furthermore, the pressure relief device is a one-way valve, which contains a small steel ball and a spring. When the pressure of the flexible pressure transmission body exceeds the predetermined pressure, it opens to relieve pressure. After the pressure relief is completed, the small steel ball is automatically reset under the elastic force of the spring to block the channel.
[0010] By utilizing the spring force and the cooperation of the steel ball, pressure relief is ensured while rapid reset is achieved without human intervention, thus improving equipment reliability. Of course, other pressure relief devices can be used instead, as long as they meet the process requirements for effective pressure relief inside the high-pressure rotary dynamic seal.
[0011] To enable the booster water injection screw pump of this utility model to better achieve high-pressure water injection in oil wells, this utility model also provides a control system containing the aforementioned booster water injection screw pump. The control system includes a motor, a high-pressure rotary dynamic seal, a flexible connector, a screw pump, a unit base, a pressure transmitter, and a control cabinet. The control cabinet contains a controller that is electrically connected to the motor. The high-pressure rotary dynamic seal is fitted onto the motor shaft. The flexible connector connects the motor shaft to the screw pump. The pressure transmitter is installed at the outlet of the screw pump and electrically connected to the controller located in the control cabinet. The control cabinet, motor, and screw pump are all fixedly mounted on the unit base.
[0012] Through the coordination of various components in the control system containing the booster screw pump, especially the comparison between the pressure value transmitted by the controller in the control cabinet through the pressure transmitter and the target pressure value that needs to be set in the controller in advance, the controller's algorithm outputs a control signal to drive the motor speed, further controlling the working intensity of the screw pump, so that the outlet water pressure meets the preset value, thereby saving the adjustment time of manual adjustment and ultimately improving work efficiency.
[0013] Furthermore, the motor is fixedly installed inside the control cabinet, with a portion of the motor extending outside the control cabinet. A heat dissipation device is provided in the control cabinet near the motor, and heat dissipation holes are provided in the control cabinet body close to the motor.
[0014] The motor is fixedly installed inside the control cabinet to protect it from external impacts. Extending the motor portion out of the cabinet allows the motor shaft and high-pressure rotary seal to be freed from the confined space of the cabinet, facilitating maintenance and replacement. The presence of a heat dissipation device near the motor and ventilation holes in the cabinet itself ensures timely dissipation of heat generated by the motor during operation, preventing excessively high operating temperatures that could affect its operational stability.
[0015] Furthermore, the controller inside the control cabinet is one of a PLC, a small logic controller, or a loop controller. The input end of the controller is connected to the pressure transmitter, and the output end is connected to the motor to form a closed-loop control.
[0016] The devices that need to be controlled will vary under different operating conditions, including logic control, loop control, and both high-voltage and low-voltage systems. When there are not many devices to be controlled on-site, a simple loop controller or a small logic controller can meet the needs of this control system. However, when there are many components to be controlled, especially when the logic control links are complex and variable, and a large number of logic controls need to be added at any time, large multi-point controllers such as PLCs are required. These can be adjusted and selected according to different on-site needs.
[0017] The beneficial effects of this utility model are: it greatly enhances the stability, long-term reliability, and field adaptability of the system during the oil well production process, especially in the middle and late stages; it reduces maintenance costs and improves work efficiency. Attached Figure Description
[0018] Figure 1 This is a schematic diagram of the high-pressure rotary dynamic seal of a booster water injection screw pump. Figure 2 This is a schematic diagram of a control system containing a booster screw pump for water injection. Detailed Implementation
[0019] To enable those skilled in the art to successfully implement all the technical solutions of this utility model, the technical solutions of this utility model will be further described below with reference to the accompanying drawings.
[0020] like Figure 1 , 2The illustrated booster water injection screw pump includes a motor 1, a high-pressure rotary dynamic seal 2, a flexible connector 3, a screw pump 4, an inlet J, and an outlet X. The high-pressure rotary dynamic seal 2 is mounted on the motor shaft 20 of the motor 1. The flexible connector 3 connects the motor shaft 20 of the motor 1 to the screw pump 4. The inlet J connects the inner cavity of the booster water injection screw pump to an external water supply pipe. The outlet X discharges the high-pressure water pressurized by the screw pump. The high-pressure rotary dynamic seal 2 includes a dynamic sealing ring 8, an end cap 10, a sealing tube 18, a flexible pressure transmitting body 11, a vent hole 12, a first shaft seal 13, a second shaft seal 19, an isolation sleeve 15, a housing 16, and a drain port 17. The dynamic sealing ring 8, end cap 10, sealing tube 18, and isolation sleeve 15 are gradually mounted on the motor shaft 20 from the end away from the motor towards the motor, and the housing 16 is used to secure them. A relatively sealed space is formed between the sealing tube 18 and the motor shaft 20. The flexible pressure transmission body 11 is fitted outside the sealing tube 18. A channel C is provided on the sealing tube 18 that communicates with the interior of the flexible pressure transmission body. The second shaft seal 19 is provided between the sealing tube 18 and the motor shaft 20 near the end cover 10 to prevent high-pressure water from entering the interior of the sealing tube 18. The first shaft seal 13 is provided near the motor to prevent liquid inside the sealing tube 18 from entering the motor. The vent hole 12 connects the high-pressure rotary dynamic seal 2 to the external space through the housing 16. A channel F is provided on the end cover 10 to connect the high-pressure water inside the screw pump with the cavity formed between the exterior of the flexible pressure transmission body 11 and the housing 16. The high-pressure rotary dynamic seal 2 also includes a long-lasting sealed liquid channel for high-pressure water to pass through and prevent it from entering the interior of the motor.
[0021] Because of the relative sealing configuration of the dynamic sealing ring, end cover, sealing tube, flexible pressure transmission body, two shaft seals, and isolation sleeve, plus the long-term sealing liquid channel, the high-pressure water entering the high-pressure rotary dynamic sealing device can be discharged through the long-term sealing liquid channel before reaching the inside of the motor, which greatly extends the time for the high-pressure water to reach the inside of the motor and effectively increases the working stability of the motor.
[0022] Specifically, the long-lasting sealed liquid channel includes a channel F on the end cap 10 that connects the high-pressure water chamber inside the screw pump to the cavity formed between the flexible pressure transmission body 11 and the housing 16, a sealing surface A between the dynamic sealing ring 8 and the end cap 10, a space between the sealing tube 18 and the motor shaft 20, a through hole C and a through hole B provided between the sealing tube 18 and the flexible pressure transmission body 11, a through hole D provided on the isolation sleeve 15 and a serpentine tube 14 connected to the through hole D, a vent hole 12, a liquid outlet E of the serpentine tube 14, and a liquid outlet 17.
[0023] The flow process of high-pressure water in the high-pressure rotary dynamic seal is as follows: As the mechanical seal formed by the dynamic sealing ring 8 and the end cover 10 operates for a long time, the high-pressure water will penetrate into the interior of the high-pressure rotary dynamic seal device through the sealing surface A at the connection between the two. It first enters the gap between the motor shaft 20 and the sealing tube 18 and flows slowly towards the motor. This gap is connected to the interior of the motor and is filled with motor oil. The high-pressure water and the motor oil continuously and slowly mix and replace each other. Under the obstruction of the second shaft seal 19, it enters the interior of the head-shaped pressure transmission body 11 through the channel B. It continuously mixes and accumulates with the motor oil inside the flexible pressure transmission body. Because the density of the high-pressure water and the motor oil is different, it will slowly sink to the bottom of the motor oil. However, as more and more high-pressure water enters, it slowly spreads upward and flows towards the motor through the gap between the rotating motor shaft 20 and the sealing tube through the channel C. Under the obstruction of the first shaft seal, the water enters the serpentine tube 14 through channel D. The serpentine tube is evenly wound around the isolation sleeve 15. High-pressure water continuously accumulates and flows within the serpentine tube 14, exiting through the end channel E of the serpentine tube 14 and entering the sedimentation chamber G. Due to the density difference with the motor oil in the sedimentation chamber, the water slowly sinks and accumulates at the drain port 17. When the drain port 17 and the vent hole 12 are opened simultaneously, the high-pressure water is discharged. Simultaneously, the vent hole 12 also serves to add motor oil to the high-pressure rotary dynamic seal, allowing for the simultaneous discharge of high-pressure water through the drain port 17 and the addition of motor oil to the high-pressure rotary dynamic seal. Of course, the first and second shaft seals can be replaced with other forms, as long as they can effectively obstruct and change the flow direction of the high-pressure water and meet the process requirements of this utility model. Through the structural design of this utility model, the service life of the motor can be greatly extended. Experiments have shown that this design increases the service life of the motor by more than four times compared to traditional methods, significantly saving oil well extraction and maintenance costs.
[0024] like Figure 1 As shown, the high-pressure rotary dynamic seal also includes a channel Q provided on the end cover 10, which connects the cavity formed by the housing 16 and the flexible pressure transmission body 11 and the screw pump cavity, and a pressure relief device 9 provided at the connection between the channel Q and the screw pump cavity.
[0025] Because of the continuous operation of the motor, especially the high-speed rotational friction between the dynamic sealing ring 8 and the end cover 10, the internal temperature will rise. Since the interior is completely sealed and filled with motor oil, the motor oil expands due to the increased temperature, causing its volume to increase. When the volume increases to a certain extent and is maintained under high temperature and pressure for a prolonged period, it will damage the dynamic seal formed by the end cover 10 and the mechanical seal 8. Therefore, this invention includes a channel Q and a pressure relief device 9. The pressure relief device 9 is a one-way valve, which contains a small steel ball and a spring. When the pressure of the flexible pressure transmission body 11 exceeds the predetermined pressure, it opens to relieve pressure. After the pressure relief is completed, the small steel ball is automatically reset under the elastic force of the spring to block the channel Q.
[0026] By using a check valve, when the pressure reaches a critical value—that is, when it exceeds the maximum tension of the spring inside the check valve—the valve will open to release pressure. When the pressure falls below the critical value, the spring retracts, sealing the passage Q. This effectively protects the stable operation of the entire high-pressure rotary dynamic seal.
[0027] like Figure 2 As shown, a control system containing a booster screw pump includes a motor 1, a high-pressure rotary dynamic seal 2, a flexible connector 3, a screw pump 4, a unit base 5, a pressure transmitter 6, and a control cabinet 7. The control cabinet 7 contains a controller that is electrically connected to the motor 1. The high-pressure rotary dynamic seal 2 is mounted on the motor shaft of the motor 1. The flexible connector 3 connects the motor shaft to the screw pump 4. The pressure transmitter 6 is installed at the outlet X of the screw pump 4 and is electrically connected to the controller located in the control cabinet 7. The control cabinet 7, the motor 1, and the screw pump 4 are all fixedly mounted on the unit base 5.
[0028] The specific working principle is as follows: The pressure sensor in pressure transmitter 6 collects the pressure value at outlet X and sends it to the controller. The controller receives the value and compares it with a preset value. When the pressure value at outlet X is less than the set pressure, the controller sends a signal to the motor to increase its rotational power, thus pressurizing the water in the screw pump. When the pressure value transmitted from the pressure transmitter is greater than the set value, the controller controls the motor to reduce its speed, thus reducing the water pressure in the screw pump. This stabilizes the overall pressurization and injection pressure, ensuring the injection pressure is met while preventing excessive pressure fluctuations that could damage the components. Fixing the control cabinet, motor, and screw pump together on the unit base facilitates transportation and prevents damage to the connections during transport due to vibration and impact, saving installation time.
[0029] The motor 1 is fixedly installed inside the control cabinet 7, with part of the motor 1 extending outside the control cabinet 7. A heat dissipation device is provided in the control cabinet 7 near the motor 1, and heat dissipation holes are provided in the control cabinet body close to the motor 1.
[0030] The controller in the control cabinet 7 is one of a PLC, a small logic controller, or a rebate controller. The input end of the controller is connected to the pressure transmitter, and the output end is connected to the motor 1 to form a closed-loop control.
[0031] The advantage of closed-loop control is that it can achieve autonomous adjustment without the need for constant manual calibration and monitoring. Of course, if it is necessary to simultaneously monitor the pressurized water injection status of multiple oil wells, the on-site operating status can be transmitted in real time to the same terminal via wired or wireless communication. Furthermore, the isolation sleeve 15 in the high-pressure rotary dynamic seal device can also adopt a dynamic seal design similar to the combination of mechanical seal 8 and end cap 10, or other types, all of which are within the protection scope of this utility model.
Claims
1. A booster water injection screw pump, comprising a motor (1), a high-pressure rotary dynamic seal (2), a flexible connector (3), a screw pump (4), an inlet (J), and an outlet (X), wherein the high-pressure rotary dynamic seal (2) is mounted on the motor shaft (20) of the motor (1), the flexible connector (3) connects the motor shaft (20) of the motor (1) to the screw pump (4), the inlet (J) connects the inner cavity of the booster water injection screw pump to an external water supply pipe, and the outlet (X) discharges high-pressure water pressurized by the screw pump, characterized in that, The high-pressure rotary dynamic seal (2) includes a dynamic sealing ring (8), an end cap (10), a sealing tube (18), a flexible pressure transmitting body (11), a vent hole (12), a first shaft seal (13), a second shaft seal (19), an isolation sleeve (15), a housing (16), and a drain port (17). The dynamic sealing ring (8), end cap (10), sealing tube (18), and isolation sleeve (15) are gradually fitted onto the motor shaft (20) from the end away from the motor towards the motor, and are sealed by the housing (16). A relatively sealed space is formed between the sealing tube (18) and the motor shaft (20). The flexible pressure transmitting body (11) is fitted outside the sealing tube (18), and is disposed on the sealing tube (18) and is located inside the flexible pressure transmitting body. The second shaft seal (19) is located between the sealing tube (18) and the motor shaft (20) near the end cover (10) to prevent high-pressure water from entering the sealing tube (18). The first shaft seal (13) is located near the motor to prevent liquid inside the sealing tube (18) from entering the motor. The vent hole (12) connects the high-pressure rotary dynamic seal (2) to the external space through the housing (16). The end cover (10) is provided with a channel (F) connecting the high-pressure water inside the screw pump and the cavity formed between the outside of the flexible pressure transmission body (11) and the housing (16). The high-pressure rotary dynamic seal (2) also includes a long-lasting sealed liquid channel for high-pressure water to pass through and prevent it from entering the motor.
2. A pressurized water injection screw pump as claimed in claim 1, characterized in that The long-lasting sealed liquid channel includes a channel (F) on the end cap (10) connecting the high-pressure water chamber inside the screw pump and the cavity formed between the flexible pressure transmission body (11) and the housing (16), a sealing surface (A) between the dynamic sealing ring (8) and the end cap (10), a space between the sealing tube (18) and the motor shaft (20), a through hole (C) and a through hole (B) provided between the sealing tube (18) and the flexible pressure transmission body (11), a through hole (D) provided on the isolation sleeve (15) and a serpentine tube (14) connected to the through hole (D), a vent hole (12), a liquid outlet (E) of the serpentine tube (14), and a liquid outlet (17).
3. A booster screw pump for water injection as described in any one of claims 1 or 2, characterized in that, It also includes a channel (Q) provided on the end cap (10) that connects the cavity formed by the housing (16) and the flexible pressure transmission body (11) and the screw pump chamber, and a pressure relief device (9) provided at the connection between the channel (Q) and the screw pump chamber.
4. A pressurized water injection screw pump as claimed in claim 3, characterized in that The pressure relief device (9) is a one-way valve with a small steel ball and a spring inside. When the pressure of the flexible pressure transmission body (11) exceeds the predetermined pressure, it opens to relieve pressure. After the pressure relief is completed, the small steel ball is automatically reset under the elastic force of the spring to block the channel (Q).
5. A control system for a pressurized water injection screw pump comprising the pressurized water injection screw pump of any one of claims 1 or 2, characterized in that The control system includes a motor (1), a high-pressure rotary dynamic seal (2), a flexible connector (3), a screw pump (4), a unit base (5), a pressure transmitter (6), and a control cabinet (7). The control cabinet (7) is equipped with a controller that is electrically connected to the motor (1). The high-pressure rotary dynamic seal (2) is mounted on the motor shaft of the motor (1). The flexible connector (3) connects the motor shaft to the screw pump (4). The pressure transmitter (6) is installed at the outlet (X) of the screw pump (4) and is electrically connected to the controller located in the control cabinet (7). The control cabinet (7), the motor (1), and the screw pump (4) are all fixedly mounted on the unit base (5).
6. A control system comprising the booster water injection screw pump of claim 3, characterized in that... The control system includes a motor (1), a high-pressure rotary dynamic seal (2), a flexible connector (3), a screw pump (4), a unit base (5), a pressure transmitter (6), and a control cabinet (7). The control cabinet (7) is equipped with a controller that is electrically connected to the motor (1). The high-pressure rotary dynamic seal (2) is mounted on the motor shaft of the motor (1). The flexible connector (3) connects the motor shaft to the screw pump (4). The pressure transmitter (6) is installed at the outlet (X) of the screw pump (4) and is electrically connected to the controller located in the control cabinet (7). The control cabinet (7), the motor (1), and the screw pump (4) are all fixedly mounted on the unit base (5).
7. A control system for a booster injection water screw pump as claimed in claim 5, wherein, The motor (1) is fixedly installed inside the control cabinet (7). Part of the motor (1) extends out of the control cabinet (7). A heat dissipation device is provided in the control cabinet (7) near the motor (1). A heat dissipation hole is provided in the control cabinet body close to the motor (1).
8. A control system containing the booster water injection screw pump of claim 3, according to claim 6, characterized by, The motor (1) is fixedly installed inside the control cabinet (7). Part of the motor (1) extends out of the control cabinet (7). A heat dissipation device is provided in the control cabinet (7) near the motor (1). A heat dissipation hole is provided in the control cabinet body close to the motor (1).
9. A control system for a booster injection water screw pump as claimed in claim 7, wherein, The controller in the control cabinet (7) is one of PLC, small logic controller, or rebate controller. The input end of the controller is connected to the pressure transmitter, and the output end is connected to the motor (1) to form a closed-loop control.
10. A control system containing the booster water injection screw pump of claim 3, wherein, The controller in the control cabinet (7) is one of PLC, small logic controller, or rebate controller. The input end of the controller is connected to the pressure transmitter, and the output end is connected to the motor (1) to form a closed-loop control.