A pipeline-type oil-water separator and method

Abstract

This invention belongs to the field of oilfield produced fluid treatment technology, and provides a pipeline-type oil-water separation device and method. The pipeline-type oil-water separation device includes a T-shaped pipe, which comprises a lower pipe, a riser, and an upper pipe. The upper pipe is located above the lower pipe. Multiple risers are arranged sequentially along the axis of the lower pipe and connect the upper and lower pipes. The invention is characterized by further including a gas-liquid separation module disposed inside the lower pipe. An air chamber is disposed at the upper part of the upper pipe, located above the riser near the inlet of the lower pipe, and has an air outlet. The gas-liquid separation module is located below the air chamber. This invention makes full use of space, improves space utilization, and reduces the oil content of the treated water.

Description

Technical Field

[0001] This invention belongs to the field of oilfield produced fluid treatment technology, specifically, it relates to a pipeline oil-water separation device and a pipeline oil-water separation method. Background Technology

[0002] Currently, most oilfields have entered the mid-to-late stages of development, with water cut exceeding 90% in several major oilfields, resulting in a severe shortage of processing capacity in the produced fluid treatment systems within the combined stations. To address this issue, methods have been proposed for on-site water distribution, treatment, and reinjection at metering stations, transfer stations, or valve group stations to alleviate the processing pressure on the combined stations.

[0003] Currently, commonly used in-situ water separation devices include hydrocyclones, high-efficiency three-phase separators, five-in-one devices, and T-tube separators. Among them, hydrocyclones have a small footprint, small size, and high processing efficiency, but they have high requirements for the stability of the incoming liquid volume and pressure, and the device needs to maintain a high pressure differential, which further limits its application range. High-efficiency three-phase separators have optimized, improved, and integrated processes in terms of liquid inlet, liquid distribution, demulsification, and oil-water interface control based on traditional three-phase separators, thus improving processing efficiency. Five-in-one devices further integrate electro-dehydration functions to reduce the water content of the produced oil, but both of these devices suffer from low volume utilization, resulting in excessively large volumes. T-tube separators have a compact structure and short residence time, and are effective for produced fluids with large oil-water density differences, but their effect is poor for produced fluids with small oil-water density differences and high emulsification.

[0004] Chinese patent document CN212881164U discloses a novel oil-water square tube separator. This device adopts a composite T-tube design and has three branch pipes to achieve efficient separation of the oil and water phases. However, this device is poorly suited for oilfields with high slug flow rates, and the quality of the effluent is difficult to guarantee.

[0005] Therefore, there is an urgent need for a water separation technology that is small in size, highly efficient, and produces good quality water. Summary of the Invention

[0006] To address the technical problems mentioned above, this invention aims to provide a pipeline-type oil-water separation device that is suitable for oilfields with high slug flow rates and produces high-quality effluent.

[0007] This invention also proposes a pipeline-type oil-water separation method, which is applicable to oilfields with high slug flow and produces high-quality effluent.

[0008] According to the present invention, a pipeline-type oil-water separator is provided, comprising a T-shaped pipe, wherein the T-shaped pipe includes a lower pipe, a riser pipe, and an upper pipe, the upper pipe being located above the lower pipe, and multiple risers being arranged sequentially along the axial direction of the lower pipe and connecting the upper pipe and the lower pipe. The pipeline-type oil-water separator further comprises a gas-liquid separation module disposed inside the lower pipe, wherein a gas chamber is disposed at the upper part of the upper pipe, the gas chamber being located above the riser pipe near the inlet of the lower pipe, and a gas outlet is disposed on the gas chamber; the gas-liquid separation module is located below the gas chamber.

[0009] In one specific embodiment, the gas-liquid separation module includes multiple coalescing plates arranged sequentially from top to bottom and fixedly connected to the lower pipe by a vertically arranged first fixing member.

[0010] In one specific embodiment, an upwardly protruding gas channel is provided on the coalescing plate, and an exhaust hole is provided at the location on the coalescing plate where the gas channel is provided.

[0011] In one specific embodiment, a liquid inlet baffle is also provided inside the lower pipe, and the liquid inlet baffle is located between the lower pipe inlet and the gas-liquid separation module.

[0012] In one specific embodiment, the distance between the gas-liquid separation module and the top and bottom of the lower pipe is 1 / 10 to 1 / 3 of the diameter of the lower pipe.

[0013] In one specific embodiment, the distance between the liquid inlet baffle and the top of the lower pipe is 1 / 10 to 1 / 5 of the diameter of the lower pipe, and the height of the liquid inlet baffle is 2 to 5 times the inlet diameter of the lower pipe. In another specific embodiment, the pipeline-type oil-water separator further includes a plurality of electric field oil removal modules arranged at intervals along the axial direction of the lower pipe, wherein the electric field oil removal modules are disposed between the gas-liquid separation module and the outlet of the lower pipe.

[0014] In one specific embodiment, the electric field oil removal module includes multiple anode plates and cathode plates arranged alternately from top to bottom. The two ends of the anode plates and cathode plates are fixedly connected to the lower pipe through insulating seals, and the middle of the anode plates and cathode plates are fixedly connected to the lower pipe through a second fixing member. The anode plates and cathode plates are powered by a power source.

[0015] In one specific embodiment, an oil baffle is provided at the upper right end inside the lower pipe, and the angle between the oil baffle and the axis of the lower pipe is in the range of 15° to 45°.

[0016] According to the present invention, a pipeline oil-water separation method is also provided, using the pipeline oil-water separation device provided according to the present invention.

[0017] Compared with the prior art, the advantages of this application are as follows.

[0018] This invention places the gas-liquid separation module inside the lower pipe and a gas reservoir above the upper pipe, making it suitable for oilfields with high slug flow rates and requiring minimal overall space. The gas-liquid separation module also performs preliminary oil-water separation, improving the quality of the effluent.

[0019] In addition, the present invention also has an electric field oil removal module inside the lower pipe. The electric field oil removal module works in conjunction with the T-shaped pipe structure of the present invention to achieve the synergistic effect of efficient demulsification by electric field and rapid oil separation by gravity field, which greatly reduces the content of emulsified oil in the effluent and improves the quality of the effluent. Attached Figure Description

[0020] The invention will now be described with reference to the accompanying drawings.

[0021] Figure 1 A schematic diagram of one embodiment of the pipeline-type oil-water separator according to the present invention is shown;

[0022] Figure 2 A schematic diagram of an embodiment of a gas-liquid separation module according to the present invention is shown;

[0023] Figure 3 A schematic diagram of an embodiment of the electric field oil removal module according to the present invention is shown.

[0024] In the diagram: 1. T-shaped pipe; 11. Lower pipe; 12. Riser pipe; 13. Upper pipe; 14. Liquid inlet; 15. Liquid inlet baffle; 16. Air tank; 17. Oil outlet; 18. Oil baffle plate; 19. Water outlet; 2. Electric field oil removal module; 21. Anode plate; 22. Cathode plate; 23. Insulating seal; 24. Second fixing component; 25. Second support component; 3. Gas-liquid separation module; 31. Coalescing plate; 32. Gas channel; 33. First fixing component; 34. First support component; 4. Power supply module; 41. Power supply; 42. Wire; 43. Terminal; 100. Pipeline oil-water separator.

[0025] In this application, all drawings are schematic and are used only to illustrate the principles of the invention, and are not drawn to scale. Detailed Implementation

[0026] The invention will now be described with reference to the accompanying drawings.

[0027] It should be noted that the directional terms or qualifiers used in this application, such as "up," "down," "front," "back," "left," and "right," are all in relation to the accompanying drawings. They are not used to define the absolute position of the components involved, but can vary depending on the specific circumstances.

[0028] Figure 1 A schematic diagram of one embodiment of a pipeline-type oil-water separator 100 according to the present invention is shown.

[0029] Figure 2 A schematic diagram of one embodiment of the gas-liquid separation module 3 according to the present invention is shown; Figure 3 A schematic diagram of an embodiment of the electric field oil removal module 2 according to the present invention is shown.

[0030] like Figure 1 As shown, a pipeline-type oil-water separator 100 includes a T-shaped pipe 1, an air reservoir 16, and a gas-liquid separation module 3. In the prior art, the T-shaped pipe 1 includes a lower pipe 11, a riser 12, and an upper pipe 13. The upper pipe 13 is located above the lower pipe 11. Multiple risers 12 are arranged sequentially along the axis of the lower pipe 11 and connect the upper pipe 13 and the lower pipe 11. In this embodiment, the lower pipe 11 is a straight pipe with an inlet (liquid inlet 14) at the left end and an outlet (water outlet 19) at the right end. The number of risers 12 is 3 to 10, evenly arranged from left to right. The upper pipe 13 is a straight pipe with its left end located above the leftmost riser 12 and an oil outlet 17 at its right end. A cylindrical air reservoir 16 is vertically arranged at the upper left end of the upper pipe 13, and an air outlet is provided at the top of the air reservoir 16. In this configuration, the gas in the produced fluid entering the lower pipe 11 can be discharged from the outlet of the gas tank 16 in a timely manner, which helps to stabilize the working pressure of the device and control the liquid level in the upper pipe.

[0031] The gas-liquid separation module 3 is located inside the lower pipe 11, below the gas reservoir 16. The gas-liquid separation module 3 can quickly separate the gas from the produced fluid entering the lower pipe 11. The gas then enters the gas reservoir 16 through the riser 12 and is finally discharged from the outlet of the gas reservoir 16. The gas-liquid separation module 3 can also perform preliminary oil-water separation.

[0032] In one specific embodiment, the gas-liquid separation module 3 includes multiple coalescing plates 31 arranged sequentially from top to bottom and fixedly connected to the lower pipe 11 by a vertically arranged first fixing member 33. Furthermore, a first support member 34 is provided between the first fixing member 33 and the coalescing plates 31 to further reinforce the coalescing plates 31. An upwardly protruding gas channel 32 is provided on the coalescing plate 31, and multiple exhaust holes (not shown in the figure) are evenly arranged along the length direction at the locations where the gas channel 32 is provided. By providing the gas channel 32 and exhaust holes, the separated gas can be discharged upwards in a timely manner, thereby accelerating the gas-liquid separation speed.

[0033] In a preferred embodiment, an inlet baffle 15 is also provided inside the lower pipe 11, and the inlet baffle 15 is vertically arranged between the inlet 14 of the lower pipe 11 and the gas-liquid separation module 3. By providing the inlet baffle 15, the produced liquid entering the lower pipe 11 can be rectified, gas-liquid separation can be initially achieved, and the operating pressure of the device can be stabilized.

[0034] In a preferred embodiment, the pipeline oil-water separator 100 further includes a plurality of electric field oil removal modules 2 arranged axially along the lower pipe 11, the electric field oil removal modules 2 being disposed between the gas-liquid separation module 3 and the outlet 19 of the lower pipe 11.

[0035] Specifically, the electric field oil removal module 2 includes multiple anode plates 21 and cathode plates 22 arranged alternately from top to bottom. The two ends of the anode plates 21 and 22 are fixedly connected to the lower pipe 11 via insulating seals 23. The middle of the anode plates 21 and 22 is fixedly connected to the lower pipe 11 via a vertically arranged second fixing member 24. Simultaneously, a second support member 25 is provided between the second fixing member 24 and the anode plates 21 and 22 to further reinforce them. The anode plates 21 and 22 are powered by a power supply module 4, which includes a connector 43, wires 42, and a power supply 41. A connector 43 is provided on each anode plate 21 and cathode plate 22, and the connector 43 is then connected to the power supply 41 via wires 42. The electric field oil removal module 2 utilizes multiple mechanisms such as shallow pool principle, electrocoagulation, electroflotation, surface coalescence, and electrophoretic migration to remove emulsified oil and ensure the quality of the effluent.

[0036] In a preferred embodiment, an oil baffle 18 is provided at the upper right end of the lower pipe 11. The oil baffle 18 is a straight plate with an angle between it and the axis of the lower pipe 11 ranging from 15° to 45°, and a horizontal length of 100 to 300 mm. By providing the oil baffle 18, the separated floating oil can be prevented from being discharged from the outlet 19. To further prevent the separated floating oil from being discharged from the outlet 19, the outlet 19 is located at a position slightly lower than the end of the lower pipe 11.

[0037] According to one specific embodiment of the present invention, the diameter of the riser 12 ranges from 50 to 200 mm, and the spacing between each riser 12 is 100 to 1000 mm. The diameter of the lower pipe 11 ranges from 100 to 700 mm, the length ranges from 1 to 10 m, and the diameters of the liquid inlet 14 and the water outlet 19 range from 50 to 200 mm. The diameter of the upper pipe 13 is greater than or equal to the diameter of the riser 12, and the diameter ranges from 50 to 200 mm. The diameter of the air manifold 16 ranges from 100 to 500 mm, and the length ranges from 100 to 500 mm.

[0038] The length of the gas-liquid separation module 3 ranges from 300 to 1000 mm, and it is 10 to 50 mm away from the liquid inlet baffle 15. The distance between the liquid inlet baffle 15 and the top and bottom of the lower pipe 11 is 1 / 10 to 1 / 3 of the diameter of the lower pipe 11. The distance between the liquid inlet baffle 15 and the liquid inlet 14 of the lower pipe 11 is 20 to 60 mm, and the distance between the liquid inlet baffle 15 and the top of the lower pipe 11 is 1 / 10 to 1 / 5 of the diameter of the lower pipe 11. The height of the liquid inlet baffle 15 is 2 to 5 times the inlet diameter of the lower pipe 11. The central axis of the liquid inlet 14 coincides with the center of the liquid inlet baffle 15. The electric field oil removal module 2 is 100 to 300 mm away from the gas-liquid separation module 3, and 50 to 100 mm away from the left end of the oil baffle 18.

[0039] In the gas-liquid separation module 3, the spacing of the coalescing plates 31 ranges from 10 to 50 mm, the diameter of the exhaust holes on the coalescing plates 31 ranges from 3 to 10 mm, and the spacing of the exhaust holes is 2 to 10 times their diameter.

[0040] In each electric field oil removal module 2, the length of the anode plate 21 and the cathode plate 22 ranges from 100 to 1000 mm, and the spacing between adjacent plates ranges from 10 to 50 mm. The electrode materials of the cathode plate 22 and the anode plate 21 are carbon-based or silicon-based materials, including but not limited to graphite, ceramics, and materials modified based on these materials. The power supply module 4's power supply 41 outputs DC current with a voltage range of 1 to 20 V and an electrode-to-water ratio range of 5 to 300 dm. 2 / L.

[0041] In a pipeline-type oil-water separation method according to the present invention, the above-mentioned pipeline-type oil-water separation device 100 is used. High-water-content produced fluid enters the lower pipe 11 through the inlet 14, first flowing through the gas-liquid separation module 3 to achieve rectification, gas-liquid separation, and preliminary oil-water separation. Then, the produced fluid enters the low-pressure electric field oil removal module 2, where floating oil and dispersed oil are rapidly separated from the produced water in a multi-layer electrode system. Emulsified oil is rapidly demulsified and coalesced under the action of the electric field force, achieving efficient oil-water separation. The treated produced water is discharged through the outlet 19, and the oil and gas separated during the process enter the upper pipe 13 through the riser 12 and are discharged promptly. Specifically, the produced fluid has a water content ≥80% and an oil-water density difference ≥0.1 g / cm³. 3The produced fluid is discharged into the lower pipe 11 from the inlet 14. The working pressure of the produced fluid is controlled within the range of 0.1 to 1.5 MPa, the temperature range is 20 to 150°C, and the residence time within the device is 2 to 15 minutes. Ultimately, the oil content in the water flowing out from the outlet 19 is ≤50 mg / L, which is a significant improvement compared to the 200 to 1000 mg / L oil content of traditional pipeline separators and T-tube separators.

[0042] Compared to traditional pipeline separators and T-tube separators, this invention allows the separated oil and gas to enter the oil and gas collection process more quickly, improving the efficiency of oil-gas-water multiphase separation. Furthermore, both the gas-liquid separation module 3 and the electric field oil removal module 2 employ multi-layer structures, fully utilizing the shallow pool principle to further enhance separation efficiency. This invention not only achieves miniaturized pipeline processing for high-water-cut produced fluid separation, improving space utilization, but also further enhances the oil-water separation performance of the equipment through the synergistic effect of a gravity field and a low-voltage electrostatic field, particularly significantly improving the reduction of oil content in the effluent.

[0043] In addition to the structure described above, the coalescing plate 31 in this invention can also be a flat plate, a corrugated plate, or one or more other forms of plate with vent holes.

[0044] In the description of this invention, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0045] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0046] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0047] Finally, it should be noted that the above description is merely a preferred embodiment of the present invention and does not constitute any limitation on the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A pipeline-type oil-water separator, comprising a T-shaped pipe (1), wherein the T-shaped pipe (1) includes a lower pipe (11), a riser (12), and an upper pipe (13), the upper pipe (13) being located above the lower pipe (11), and multiple risers (12) being arranged sequentially along the axial direction of the lower pipe (11) and connecting the upper pipe (13) and the lower pipe (11), characterized in that, The pipeline oil-water separator also includes a gas-liquid separation module (3) disposed inside the lower pipe (11), wherein, An air bag (16) is provided at the upper part of the upper pipe (13). The air bag (16) is located above the riser (12) near the inlet of the lower pipe (11). An air outlet is provided on the air bag (16). The gas-liquid separation module (3) is located below the gas bag (16); The gas-liquid separation module (3) includes multiple coalescing plates (31), which are arranged sequentially from top to bottom. An upwardly protruding gas channel (32) is provided on the coalescing plate (31), and an exhaust hole is provided at the position where the gas channel (32) is provided on the coalescing plate (31). The distance between the gas-liquid separation module (3) and the top and bottom of the lower pipe (11) is 1 / 10 to 1 / 3 of the diameter of the lower pipe (11).

2. The pipeline-type oil-water separator according to claim 1, characterized in that, Multiple coalescing plates (31) are arranged sequentially from top to bottom and are fixedly connected to the lower pipe (11) by a vertically arranged first fixing member (33).

3. The pipeline-type oil-water separator according to claim 1, characterized in that, A liquid inlet baffle (15) is also vertically installed inside the lower pipe (11), and the liquid inlet baffle (15) is located between the inlet of the lower pipe (11) and the gas-liquid separation module (3).

4. The pipeline-type oil-water separator according to claim 3, characterized in that, The distance between the liquid inlet baffle (15) and the top of the lower tube (11) is 1 / 10 to 1 / 5 of the diameter of the lower tube (11), and the height of the liquid inlet baffle (15) is 2 to 5 times the inlet diameter of the lower tube (11).

5. The pipeline oil-water separator according to any one of claims 1 to 4, characterized in that, The pipeline oil-water separator also includes a plurality of electric field oil removal modules (2) arranged axially along the lower pipe (11), and the electric field oil removal modules (2) are arranged between the gas-liquid separation module (3) and the outlet of the lower pipe (11).

6. The pipeline-type oil-water separator according to claim 5, characterized in that, The electric field oil removal module (2) includes multiple anode plates (21) and cathode plates (22) arranged alternately from top to bottom. The two ends of the anode plates (21) and cathode plates (22) are fixedly connected to the lower pipe (11) through insulating seals (23). The middle part of the anode plates (21) and cathode plates (22) is fixedly connected to the lower pipe (11) through a second fixing member (24). The anode plates (21) and cathode plates (22) are powered by a power supply (41).

7. The pipeline oil-water separator according to any one of claims 1 to 4, characterized in that, An oil baffle (18) is provided at the upper right end inside the lower pipe (11), and the angle between the oil baffle (18) and the axis of the lower pipe (11) is in the range of 15° to 45°.

8. A pipeline-type oil-water separation method, characterized in that, Use the pipeline oil-water separator according to any one of claims 1 to 7.

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