Pipeline cleaner for reducing slug flow
By incorporating a spiral flow channel and a slanted cut surface design for the pipeline cleaning tool, combined with a pressure relief device, the problems of slugging and jamming in traditional pipeline cleaning tools have been solved, enabling efficient and safe subsea pipeline cleaning operations.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- CNOOC TIANJIN BRANCH
- Filing Date
- 2026-03-04
- Publication Date
- 2026-04-21
AI Technical Summary
Traditional pipeline cleaning tools are prone to causing concentrated blockage flow during subsea pipeline cleaning operations, resulting in pressure on downstream platforms, low cleaning efficiency, limited sediment carrying capacity, and easy jamming under complex working conditions.
A pipeline pig designed to reduce slug flow employs a spiral flow channel and a shank cut-off structure to create bypass flow. Combined with a rotary advance and drill bit design, it enhances the ability to remove deposits and is equipped with a pressure relief device to cope with pressure fluctuations.
It effectively reduces the formation and impact intensity of slug flow, improves pipeline cleaning efficiency, reduces the risk of ball jamming, and ensures the stable operation and safety of the pipeline system.
Smart Images
Figure CN121892453A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of oil and gas transportation technology, and in particular to a pipeline pig that reduces slug flow. Background Technology
[0002] In the field of oil and gas transportation, when subsea pipelines transport oil, gas and water mixtures for a long time, the inner walls are prone to depositing substances such as paraffin wax and silt, which affects the transportation efficiency and may cause safety hazards. Therefore, it is necessary to use pipeline cleaning tools regularly to ensure the smooth flow of pipelines and the normal operation of the transportation system.
[0003] Existing pipeline pigs are mostly plug-like structures that rely on fluid propulsion for translational movement. They have almost no bypass flow and can easily and quickly push the fluid in front to form concentrated slug flow, putting pressure on the downstream platform. Moreover, the sediment-carrying capacity during pigging is limited, and the efficiency of translational pigging operations is low. In cases with a large amount of sediment or complex environments, jamming can easily occur, affecting the safety and stability of the operation. Therefore, it is of great significance to propose a new type of pipeline pig that can reduce slug flow. Summary of the Invention
[0004] To address the problems of traditional pipeline cleaning tools in subsea pipeline cleaning operations, such as the tendency to cause concentrated slug flows, create receiving pressure on downstream platforms, low cleaning efficiency, limited sediment carrying capacity, and susceptibility to jamming under complex conditions, this invention provides a pipeline cleaning tool that reduces slug flows.
[0005] The present invention is achieved by the following technical solution.
[0006] A pipeline cleaning device for reducing slug flow includes a cleaning body, a drill bit on one side of the cleaning body, a drill tail on the side of the cleaning body away from the drill bit, and a beveled surface on the drill tail; the cleaning body has at least one spiral flow channel groove.
[0007] Furthermore, the spiral flow channel groove is spirally formed on the body of the cleaner, with one end extending to the drill bit and the other end extending to the drill tail.
[0008] Furthermore, the cleaner body is provided with a pressure relief device, which includes a pressure relief sliding rod that slides within the cleaner body via a spring.
[0009] Furthermore, the pressure relief sliding rod includes a sliding rod body, which is connected to the pressure plate via a connecting rod, and a flow groove is formed between the connecting rod and the pressure plate; the bottom end of the sliding rod body is provided with a sliding rod bottom drill bit, and the side of the sliding rod bottom drill bit away from the sliding rod body is connected to the sliding rod top drill bit.
[0010] Furthermore, the cleaner body has a sliding groove and a limiting groove, with the middle section of the sliding rod slidably disposed in the sliding groove; the pressure plate is slidably disposed in the limiting groove, and the spring is disposed between the bottom wall of the limiting groove and the pressure plate.
[0011] Furthermore, the sliding groove penetrates the drill bit, and a through sliding hole is opened on the drill tail, which communicates with the sliding groove.
[0012] Furthermore, the end of the sliding rod away from the bottom drill bit is slidably disposed in the sliding hole, and the diameter of the sliding rod is the same as the diameter of the sliding hole.
[0013] Furthermore, the bottom drill bit of the sliding rod is slidably disposed within the sliding groove, and the diameter of the bottom drill bit of the sliding rod is the same as the diameter of the sliding groove; the diameter of the top drill bit of the sliding rod is smaller than the diameter of the bottom drill bit of the sliding rod.
[0014] Furthermore, a limiting rod is provided in the limiting groove, the axis of the limiting rod is parallel to the axis of the sliding rod body, a limiting hole is opened on the pressure plate, the limiting rod passes through the limiting hole, and the limiting rod and the limiting hole are slidably engaged.
[0015] This application has the following beneficial effects: (1) The present invention forms a bypass flow through a spiral flow channel, disperses the fluid impact force and reduces the moving speed of the pig, slows down the formation of slug flow and impact intensity from the source, avoids the downstream platform from having a receiving bottleneck due to concentrated liquid inflow, and ensures the stable operation of the pipeline system.
[0016] (2) The present invention uses the slanted cut surface of the drill tail and the spiral flow channel to achieve rotation and forward movement. Combined with the drill bit design, it can efficiently peel off the deposits on the pipe wall and break up obstacles in front, greatly improve the cleaning efficiency and reduce the risk of stuck ball. It is suitable for complex pipe working conditions and enhances the safety of operation. Attached Figure Description
[0017] Figure 1 This is a schematic diagram of the single-channel pig of the present invention; Figure 2 This is a schematic diagram of the dual-channel pig of the present invention; Figure 3 This is a schematic diagram of the structure of the three-channel pig of the present invention; Figure 4 This is a cross-sectional view of the single-channel pig equipped with a pressure relief device according to the present invention; Figure 5 This is a state diagram of the single-channel pig with pressure relief device of the present invention when the pressure relief device is not triggered; Figure 6 This is a state diagram of the single-channel pig pressure relief device of the present invention when it is triggered; Figure 7 This is a schematic diagram of the pressure relief sliding rod of the present invention; Figure 8 yes Figure 7 Enlarged view of section A.
[0018] The components include: 1. Cleaner body; 2. Pressure relief device; 3. Drill bit; 4. Drill tail; 5. Spiral flow channel groove; 6. Beveled surface; 200. Pressure relief sliding rod; 201. Pressure plate; 202. Limiting hole; 203. Connecting rod; 204. Flow groove opening; 205. Sliding rod bottom drill bit; 206. Sliding rod top drill bit; 207. Sliding rod body; 208. Sliding groove; 209. Limiting groove; 210. Pressure sensor; 211. Spring; 212. Limiting rod; 213. Sliding hole. Detailed Implementation
[0019] The present patent application will be further described below with reference to the accompanying drawings and embodiments.
[0020] Example 1 Reference Figure 1-3 A pipeline cleaning device for reducing slug flow includes a cleaning body 1 that is movably installed inside the subsea pipeline. In order to solve the problem that traditional cleaning balls have limited capacity to carry sediment and are prone to jamming during a single cleaning operation, a drill bit 3 is fixedly installed on one side of the cleaning body 1, and a drill tail 4 is fixedly installed on the side of the cleaning body 1 away from the drill bit 3. The drill tail 4 has a beveled surface 6, and the cleaning body 1 has a spiral flow channel groove 5.
[0021] The cleaner body 1 has at least one spiral flow channel groove 5, which is spirally opened on the cleaner body 1. One end of the spiral flow channel groove 5 extends to the drill bit 3, and the other end of the spiral flow channel groove 5 extends to the drill tail 4.
[0022] The surface of the cleaner body 1 is designed with a spiral flow channel 5, which is its core functional component. During pipeline cleaning operations, the fluid (oil, gas and water mixture, etc.) inside the pipeline will be connected between the front and back of the cleaner body 1 through the spiral flow channel 5.
[0023] Traditional pipeline pigs resemble "plugs," moving forward horizontally under the propulsion of fluid with almost no bypass flow, quickly creating a concentrated slug flow. In contrast, the spiral flow channel 5 of this invention allows some fluid to pass through the channel, creating a bypass flow and dispersing the impact force of the fluid. Simultaneously, the presence of the bypass flow reduces the propulsive force on the pig, significantly slowing its movement. The slower movement speed and dispersed fluid impact mitigate and disperse the formation and intensity of slug flows at the source, preventing downstream platforms from experiencing receiving bottlenecks due to a large influx of fluid in a short period.
[0024] The shank 4 of the main body 1 of the cleaning device adopts a special oblique cut surface 6 design. When the fluid in the subsea pipeline acts on the shank, the asymmetrical structure of the cut surface causes uneven distribution of fluid pressure at the shank, resulting in an eccentric force deviating from the axis. This eccentric force generates a torque that causes the cleaning device to rotate. Combined with the guiding effect of the spiral flow channel 5 on the fluid, the cleaning device rotates and advances within the subsea pipeline. The continuous rotational motion can more effectively remove deposits from the pipe wall and carry them away through the centrifugal force generated by the rotation. Compared with the horizontal cleaning of traditional cleaning devices, this significantly improves the cleaning efficiency.
[0025] The drill bit 3 of the main body 1 of the cleaning unit adopts a drill bit-shaped design. This structure is designed for situations where there are many sediments or complex conditions inside the subsea pipeline. During the rotation and advancement of the cleaning unit, the drill bit-shaped head can break up and guide any sediments or obstacles that may be present ahead, preventing the cleaning unit from getting stuck in sediment (traditional foam balls are prone to getting stuck due to sediment accumulation). Its shape design ensures that the cleaning unit can still operate stably in complex pipeline environments, significantly reducing the risk of sticking and ensuring the safety of the cleaning operation.
[0026] To address the varying slug strength and flow rates across different subsea pipelines, pipeline pigs are designed in multiple models, including single-channel, dual-channel, and triple-channel designs. The depth and width of the channels are also adjustable. The evenly distributed multi-channel structure generates a resultant torque when the fluid within the pipeline impacts the channels, providing the pig with the propulsion for rotation (dual-channel and triple-channel pigs can rotate without a tail section design). Different numbers of channels correspond to different bypass flow rates and movement speeds, allowing for flexible selection based on actual pipeline conditions (such as slug strength and sediment load), ensuring efficient and safe pigging operations in various scenarios.
[0027] Example 2 Reference Figure 4-7 To prevent excessive pressure in the subsea pipeline from damaging the pipeline during the use of the single-channel pig, a pressure relief device 2 is provided inside the main body 1 of the cleaner. The pressure relief device 2 includes a pressure relief sliding rod 200, which is slidably installed inside the main body 1 of the cleaner. A spring 211 and a limiting rod 212 are fixedly installed inside the main body 1 of the cleaner. The limiting rod 212 is slidably engaged with the pressure relief sliding rod 200.
[0028] Specifically, the pressure relief sliding rod 200 consists of a sliding rod body 207, a pressure plate 201, a connecting rod 203, a sliding rod bottom drill bit 205, and a sliding rod top drill bit 206. The sliding rod body 207 is fixedly connected to the pressure plate 201 through the connecting rod 203, and a flow groove 204 is opened between the connecting rod 203 and the pressure plate 201. The sliding rod bottom drill bit 205 is fixedly installed on the end of the sliding rod body 207 near the drill bit 3, and the sliding rod top drill bit 206 is fixedly installed on the side of the sliding rod bottom drill bit 205 away from the sliding rod body 207.
[0029] The cleaner body 1 has a sliding groove 208 and a limiting groove 209. The middle section of the sliding rod 207 is slidably installed in the sliding groove 208, the pressure plate 201 is slidably installed in the limiting groove 209, the flow port 204 is located in the sliding groove 208, and the spring 211 is fixedly installed in the limiting groove 209. Specifically, the spring 211 is fixedly installed between the bottom wall of the limiting groove 209 and the pressure plate 201. The sliding groove 208 passes through the drill bit 3, and the drill tail 4 has openings... A sliding hole 213 communicates with a sliding groove 208. A bottom drill bit 205 of the sliding rod is slidably installed within the sliding groove 208, with a diameter identical to that of the sliding groove 208. The end of the sliding rod body 207 furthest from the bottom drill bit 205 is slidably installed within the sliding hole 213, with a diameter identical to that of the sliding hole 213. The diameter of the top drill bit 206 of the sliding rod is smaller than that of the bottom drill bit 205. A limiting rod 212 is fixedly installed within a limiting groove 209, with its axis parallel to the axis of the sliding rod body 207. A limiting hole 202 is opened on the pressure plate 201, through which the limiting rod 212 passes, and the limiting rod 212 slides within the limiting hole 202.
[0030] Because the bypass flow of the single-channel pig is relatively small, in order to prevent blockage caused by occasional increases in subsea pipeline pressure and flow velocity during use, the pressure relief device 2 of this device plays a pressure relief role. A spring 211 with appropriate elasticity is selected. When the pig is working in the subsea pipeline, if the pressure in the pipe on the drill tread 4 side is too high, when the pressure is sufficient to overcome the elasticity of the spring 211, the sliding rod 207 and the pressure plate 201 will be pushed by air or water pressure and compress the spring 211. When the pressure plate 201 and the sliding rod 207 move towards the drill bit 3 end, the bottom drill bit 205 of the sliding rod disengages from the sliding groove 208 in the body of the cleaner. At this time, the high-pressure liquid and gas near the drill tread 4 end of the body of the cleaner can overflow through the sliding hole 213 and the sliding groove 208 to the end of the body of the cleaner near the drill bit 3, thereby realizing the pressure relief function.
[0031] This application may also include a pressure sensor 210 within the limiting groove 209. The pressure sensor 210 is positioned below the spring 211, meaning it is installed on the inner wall of the limiting groove 209 near the drill bit 3. The pressure sensor 210 allows for real-time monitoring of pressure changes. However, when installing the pressure sensor 210, both the power supply and signal transmission devices must be installed within the cleaner body 1, and the signal transmission device must be connected to an external computer. If real-time pressure monitoring is not required, the pressure sensor 210 may be omitted, and its presence or absence will not affect the normal cleaning function of the device. Similarly, when the pipe pressure is well-controlled, the pressure relief device 2 may not be required within the single-channel pig, yet it can still function normally in reducing slug flow and cleaning the pipeline. The remaining features are the same as in Embodiment 1.
[0032] The embodiments described herein are preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Therefore, all equivalent changes made in accordance with the structure, shape, and principle of the present invention should be covered within the scope of protection of the present invention.
Claims
1. A pipeline cleaning device for reducing slug flow, comprising a cleaning device body (1), characterized in that: The cleaner body (1) has a drill bit (3) on one side, and a drill tail (4) is formed on the side of the cleaner body (1) away from the drill bit (3). A chamfered surface (6) is provided on the drill tail (4); at least one spiral flow channel groove (5) is provided on the cleaner body (1).
2. A pipeline pig for reducing slug flow according to claim 1, characterized in that: The spiral flow channel (5) is spirally opened on the body (1) of the cleaner. One end of the spiral flow channel (5) extends to the drill bit (3) and the other end extends to the drill tail (4).
3. A pipeline pig for reducing slug flow according to claim 1, characterized in that: The cleaner body (1) is provided with a pressure relief device (2), which includes a pressure relief sliding rod (200) that slides within the cleaner body (1) via a spring (211).
4. A pipeline pig for reducing slug flow according to claim 3, characterized in that: The pressure relief sliding rod (200) includes a sliding rod body (207), which is connected to the pressure plate (201) via a connecting rod (203). A flow slot (204) is provided between the connecting rod (203) and the pressure plate (201). The bottom end of the sliding rod body (207) is provided with a sliding rod bottom drill bit (205), and the side of the sliding rod bottom drill bit (205) away from the sliding rod body (207) is connected to the sliding rod top drill bit (206).
5. A pipeline pig for reducing slug flow according to claim 4, characterized in that: The cleaner body (1) has a sliding groove (208) and a limiting groove (209) inside. The middle section of the sliding rod (207) is slidably disposed in the sliding groove (208). The pressure plate (201) is slidably disposed in the limiting groove (209). The spring (211) is disposed between the bottom wall of the limiting groove (209) and the pressure plate (201).
6. A pipeline pig for reducing slug flow according to claim 5, characterized in that: The sliding groove (208) penetrates the drill bit (3), and a through sliding hole (213) is opened on the drill tail (4), which is connected to the sliding groove (208).
7. A pipeline pig for reducing slug flow according to claim 6, characterized in that: The sliding rod (207) is slidably disposed in the sliding hole (213) at the end away from the bottom drill bit (205), and the diameter of the sliding rod (207) is the same as the diameter of the sliding hole (213).
8. A pipeline pig for reducing slug flow according to claim 5, characterized in that: The bottom drill bit (205) of the sliding rod is slidably disposed in the sliding groove (208), and the diameter of the bottom drill bit (205) is the same as the diameter of the sliding groove (208); the diameter of the top drill bit (206) of the sliding rod is smaller than the diameter of the bottom drill bit (205).
9. A pipeline pig for reducing slug flow according to claim 5, characterized in that: The limiting groove (209) is provided with a limiting rod (212), the axis of the limiting rod (212) is parallel to the axis of the sliding rod (207), and a limiting hole (202) is opened on the pressure plate (201). The limiting rod (212) passes through the limiting hole (202) and the limiting rod (212) slides with the limiting hole (202).