A multi-stage oil-water separation device for water injection marine pipelines

Abstract

The application discloses a kind of multistage oil-water separation devices of water injection sea pipe, including multiple groups of first oil skimming device, multiple groups of second oil skimmer and with multiple groups of second oil skimmer outlet communication second oil collecting pipe;The first oil skimming device is arranged on the water injection sea pipe, and the outlet of the first oil skimming device is communicated with the inlet of the second oil skimming device, and the outlet of the second oil skimming device is communicated with the second oil collecting pipe, and the outlet of the second oil collecting pipe is communicated with the crude oil conveying pipe.The present application has the advantages of simple manufacturing process, convenient operation, no moving equipment, etc., which can reduce the energy consumption of the equipment, has a long service life, and can separate oil and water in the water injection sea pipe by using the pressure difference between the pipelines, reduce the oil content, and further improve the quality of the reinjection water, reduce the damage of the bottom layer caused by the oil content in the reinjection water.

Description

Technical Field

[0001] This invention belongs to the field of oil, gas and water treatment, and specifically relates to a multi-stage oil-water separation device for water injection subsea pipelines. Background Technology

[0002] With the continuous development of offshore oil exploration and development technologies, the scale of offshore oilfield exploitation is expanding daily, and water injection pipeline operations have become an important means of maintaining oilfield production. However, during the water injection process, because the water source may contain a certain amount of oil and other impurities, traditional water injection pipelines will directly inject this oil and impurities into the formation, which will not only affect the water injection effect but may also pollute the formation, thereby affecting the oilfield's exploitation efficiency and production safety.

[0003] The patent with publication number CN 218530084U discloses a water injection filter for marine oil and gas fields. It filters reinjected water and improves the quality of reinjected water by adding a moving box, motor and other devices. However, this patent has problems such as complex equipment, high energy consumption, short lifespan and inability to remove oil from reinjected water. Summary of the Invention

[0004] This invention is proposed to solve the problems existing in the prior art, and its purpose is to provide a multi-stage oil-water separation device for water injection subsea pipelines.

[0005] This invention is achieved through the following technical solution:

[0006] A multi-stage oil-water separation device for a water injection subsea pipeline includes multiple sets of primary oil skimmers, multiple sets of secondary oil skimmers, and a secondary oil collection pipe connected to the outlets of the multiple sets of secondary oil skimmers. The primary oil skimmers are installed on the water injection subsea pipeline, the outlet of the primary oil skimmer is connected to the inlet of the secondary oil skimmer, the outlet of the secondary oil skimmer is connected to the secondary oil collection pipe, and the outlet of the secondary oil collection pipe is connected to the crude oil delivery pipe.

[0007] In the above technical solution, the primary oil skimming device includes two sets of primary oil skimmers and a primary oil collection pipe with both ends connected to the outlets of the two sets of primary oil skimmers respectively. The two sets of primary oil skimmers are symmetrically arranged with the primary oil collection pipe as the center. The primary oil skimmer includes a water injection subsea pipeline connecting pipe, a primary oil skimming pipe that is vertically connected to the water injection subsea pipeline connecting pipe in the horizontal plane, and a primary oil transport pipe connected to the primary oil skimming pipe.

[0008] In the above technical solution, the inner and outer diameters of the primary oil collection pipe and the primary oil delivery pipe are the same; the outer diameter of the primary oil collection pipe is 1 / 5 to 1 / 6 of the outer diameter of the water injection subsea pipe to which it is connected; the water injection subsea pipe is coaxially arranged with the water injection subsea pipe and has the same roundness; the length of the water injection subsea pipe between the two sets of primary oil skimmers in the primary oil skimming device is 450mm to 550mm, preferably 500mm; the center distance between the two sets of primary oil skimmers is 650mm to 750mm.

[0009] In the above technical solution, the water injection subsea pipeline connecting pipe is connected to the water injection subsea pipeline via a flange.

[0010] In the above technical solution, the connection end of the primary oil skimmer and the water injection subsea pipeline is located at the upper part of the water injection subsea pipeline, and the end face of the connection end of the primary oil skimmer and the water injection subsea pipeline is a slope, and the included angle between the end face of the slope and the cross-section of the primary oil skimmer is 58° to 62°, preferably 60°; the primary oil skimmer and the water injection subsea pipeline are connected by welding.

[0011] In the above technical solution, the primary oil delivery pipe and the primary skimming pipe are connected through a primary adapter ball valve, and the primary oil delivery pipe and the primary oil collection pipe are connected through a primary elbow.

[0012] The primary adapter ball valve is connected to the primary oil supply pipe and the primary oil skimming pipe via flanges and is sealed with metal spiral wound gaskets to prevent liquid leakage.

[0013] The primary elbow is directly welded and fixed to the primary oil pipeline and the primary oil collection pipeline; the primary elbow is a 90° short radius elbow.

[0014] In the above technical solution, the number of secondary oil skimmers is the same as the number of primary oil collection pipes; the spacing between adjacent secondary oil skimmers is the same as the spacing between two sets of primary oil skimmers in the primary oil skimmer device; the secondary oil skimmer includes a primary oil collection pipe connecting pipe, a secondary oil skimmer vertically connected to the primary oil collection pipe connecting pipe on the horizontal plane, and a secondary oil delivery pipe connected to the secondary oil skimmer.

[0015] In the above technical solution, the primary oil collection pipe is connected to the primary oil collection pipe through a flange; the inner and outer diameters of the secondary oil collection pipe, the secondary skimming pipe and the secondary oil transport pipe are all the same; the outer diameter of the secondary oil collection pipe is 1 / 4 to 1 / 5 of the outer diameter of the primary oil collection pipe.

[0016] In the above technical solution, the horizontal positions of the primary skimming pipe, primary oil transport pipe, primary oil collection pipe, secondary oil collection pipe, and secondary oil transport pipe are all not higher than the horizontal position of the water injection subsea pipeline.

[0017] In the above technical solution, the primary oil collection pipe, the water injection subsea pipeline connecting pipe, the primary oil skimming pipe, the primary oil transport pipe, the primary elbow, the secondary oil collection pipe, the primary oil collection pipe connecting pipe, the secondary oil skimming pipe, the secondary oil transport pipe and the secondary elbow are all made of duplex stainless steel. The outside of the pipe is coated with primer and topcoat for corrosion protection. The primer is a phenolic epoxy resin type, and the topcoat is a two-component solvent-free phenolic epoxy type. The anti-corrosion coating material on the inner wall of the pipe is glass flake paint.

[0018] The beneficial effects of this invention are:

[0019] This invention provides a multi-stage oil-water separation device for subsea water injection pipelines. The manufacturing process is simple, the operation is convenient, and there is no increase in energy consumption due to moving equipment. It has a long service life and can use the pressure difference between pipelines to separate oil and water in the subsea water injection pipeline, reduce the oil content, thereby further improving the quality of reinjected water and reducing the damage to the bottom layer caused by oil in the reinjected water. Attached Figure Description

[0020] Figure 1 This is a perspective view of the present invention;

[0021] Figure 2 This is the front view of the present invention.

[0022] in:

[0023] 1. Water injection subsea pipeline; 2. Crude oil transmission pipeline; 3. Primary oil collection pipeline; 4. Water injection subsea pipeline connecting pipe; 5. Primary skimming pipe; 6. Primary oil transmission pipeline; 7. Primary adapter ball valve; 8. Primary elbow; 9. Secondary oil collection pipeline; 10. Primary oil collection pipeline connecting pipe; 11. Secondary skimming pipe; 12. Secondary oil transmission pipeline; 13. Secondary adapter ball valve; 14. Secondary elbow.

[0024] For those skilled in the art, other related figures can be obtained from the above figures without any creative effort. Detailed Implementation

[0025] To enable those skilled in the art to better understand the technical solution of the present invention, the technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0026] like Figure 1 , 2 As shown, a multi-stage oil-water separation device for a water injection subsea pipeline includes multiple sets of primary oil skimmers, multiple sets of secondary oil skimmers, and a secondary oil collection pipe 9 connected to the outlets of the multiple sets of secondary oil skimmers. The primary oil skimmers are installed on the water injection subsea pipeline 1, the outlet of the primary oil skimmers is connected to the inlet of the secondary oil skimmers, the outlet of the secondary oil skimmers is connected to the secondary oil collection pipe 9, and the outlet of the secondary oil collection pipe 9 is connected to the crude oil delivery pipe 2.

[0027] The primary oil skimming device includes two sets of primary oil skimmers and a primary oil collection pipe 3 with both ends connected to the outlets of the two sets of primary oil skimmers respectively. The two sets of primary oil skimmers are symmetrically arranged with the primary oil collection pipe 3 as the center.

[0028] The primary skimmer includes a water injection subsea pipeline connecting pipe 4, a primary skimmer pipe 5 that is vertically connected to the water injection subsea pipeline connecting pipe 4 in a horizontal plane, and a primary oil delivery pipe 6 that is connected to the primary skimmer pipe 5.

[0029] The water injection subsea pipeline connecting pipe 4 is connected to the water injection subsea pipeline 1 via a flange;

[0030] The inner and outer diameters of the primary oil collection pipe 3, the primary oil delivery pipe 6, and the primary oil collection pipe connecting pipe 10 are all the same.

[0031] The outer diameter of the primary oil collection pipe 3 is 1 / 5 to 1 / 6 of the outer diameter of the water injection subsea pipe 1;

[0032] The water injection subsea pipeline connecting pipe 4 is coaxially arranged with the water injection subsea pipeline 1 and has the same roundness.

[0033] The length of the water injection subsea pipe 1 between the two sets of primary oil skimmers in the primary oil skimmer device is 450mm to 550mm, preferably 500mm; the center-to-center distance between the two sets of primary oil skimmers is 650mm to 750mm.

[0034] The connection end of the primary oil skimming pipe 5 and the water injection subsea pipeline connecting pipe 4 is located at the upper part of the water injection subsea pipeline connecting pipe 4, and the end face of the connection end of the primary oil skimming pipe 5 and the water injection subsea pipeline connecting pipe 4 is a slope, and the angle between the end face of the slope and the cross-section of the primary oil skimming pipe 5 is 58° to 62°, preferably 60°.

[0035] The primary skimming pipe 5 is connected to the water injection subsea pipeline connecting pipe 4 by welding.

[0036] The primary oil supply pipe 6 and the primary oil skimming pipe 5 are connected by a primary adapter ball valve 7, and the primary oil supply pipe 6 and the primary oil collection pipe 3 are connected by a primary elbow 8.

[0037] The primary adapter ball valve 7 is connected to the primary oil supply pipe 6 and the primary oil skimming pipe 5 via flanges and is sealed with metal spiral wound gaskets to prevent liquid leakage.

[0038] The primary elbow 8 is directly welded and fixed to the primary oil pipeline 6 and the primary oil collection pipeline 3; the primary elbow 8 adopts a 90° short radius elbow to reduce fluid resistance and optimize the oil-water separation effect.

[0039] The number of the secondary oil skimmers is the same as the number of the primary oil collection pipes 3;

[0040] The secondary oil skimmer includes a primary oil collection pipe connecting pipe 10, a secondary oil skimming pipe 11 that is vertically connected to the primary oil collection pipe connecting pipe 10 on a horizontal plane, and a secondary oil delivery pipe 12 that is connected to the secondary oil skimming pipe 11.

[0041] The primary oil collection pipe 10 is connected to the primary oil collection pipe 3 via a flange;

[0042] The inner and outer diameters of the secondary oil collection pipe 9, the secondary oil skimming pipe 11, and the secondary oil delivery pipe 12 are all the same.

[0043] The outer diameter of the secondary oil collection pipe 9 is 1 / 4 to 1 / 5 of the outer diameter of the primary oil collection pipe 3;

[0044] The primary oil collection pipe connecting pipe 10 is coaxially arranged with the primary oil collection pipe 3 and has the same roundness.

[0045] The spacing between adjacent secondary skimmers is the same as the spacing between two sets of primary skimmers in the primary skimmer device.

[0046] The connection end of the secondary oil skimmer 11 and the primary oil collection pipe 10 is located at the upper part of the primary oil collection pipe 10, and the end face of the connection end of the secondary oil skimmer 11 and the primary oil collection pipe 10 is a slope, and the angle between the end face of the slope and the cross-section of the secondary oil skimmer 11 is 58° to 62°, preferably 60°.

[0047] The secondary skimming pipe 11 is connected to the primary oil collection pipe 10 by welding.

[0048] The secondary oil delivery pipe 12 and the secondary oil skimming pipe 11 are connected by a secondary adapter ball valve 13, and the secondary oil delivery pipe 12 and the secondary oil collection pipe 9 are connected by a secondary elbow 14.

[0049] The secondary adapter ball valve 13 is connected to the secondary oil delivery pipe 12 and the secondary skimming pipe 11 via a flange and is sealed with a metal spiral wound gasket to prevent liquid leakage.

[0050] The secondary elbow 14 is directly welded and fixed to the secondary oil pipeline 12 and the secondary oil collection pipe 9;

[0051] The secondary oil collection pipe 9 is connected to the crude oil delivery pipe 2 via a duplex stainless steel flange and sealed with a spiral wound gasket to prevent liquid leakage.

[0052] The horizontal positions of the primary skimming pipe 5, primary oil transfer pipe 6, primary oil collection pipe 3, secondary oil collection pipe and secondary oil transfer pipe 12 are all not higher than the horizontal position of the water injection subsea pipe 1, so as to avoid damage to the equipment caused by seabed scraping;

[0053] The primary oil collection pipe 3, the water injection subsea pipeline connecting pipe 4, the primary oil skimming pipe 5, the primary oil transport pipe 6, the primary elbow 8, the secondary oil collection pipe 9, the primary oil collection pipe connecting pipe 10, the secondary oil skimming pipe 11, the secondary oil transport pipe 12, and the secondary elbow 14 are all made of duplex stainless steel. The outside of the pipes is coated with primer and topcoat for corrosion protection. The primer is a phenolic epoxy resin type, and the topcoat is a two-component solvent-free phenolic epoxy type. The anti-corrosion coating material on the inner wall of the pipeline is high temperature resistant and corrosion resistant glass flake paint.

[0054] The valve bodies of the primary adapter ball valve 7 and the secondary adapter ball valve 13 are made of duplex stainless steel, and the valve core is made of 316SS. The surface anti-corrosion requirements are the same as those for the pipeline.

[0055] The primary adapter ball valve 7 and the secondary adapter ball valve 13 are controlled by a PLC to ensure timely transmission of sludge and oil and shutdown during maintenance of the water injection subsea pipeline.

[0056] This invention achieves highly efficient oil-water separation: During the transport of production water from the platform to the seabed in the injection pipeline, some oil phase floats to the top of the pipeline due to aggregation and density differences. By using a multi-stage oil skimming device, and with each stage employing multiple sets of skimmers, the pressure difference between the injection pipeline and the crude oil transport pipeline is utilized to achieve multi-stage oil-water separation in the oil-water mixture. Each stage further improves the efficiency of oil-water separation, resulting in a significant reduction in the oil content of the final reinjected water.

[0057] The invention has a compact structure and occupies little space: the entire device adopts a compact design, and the oil skimming devices and pipelines at each stage are carefully laid out, which makes the overall space occupied small and facilitates installation and deployment in limited seabed space;

[0058] This invention is corrosion resistant and durable: all pipelines are made of duplex stainless steel and have undergone strict anti-corrosion treatment, including coating with primer and topcoat. These materials are resistant to high temperature and corrosion, which can effectively extend the service life of the device and reduce maintenance and replacement costs caused by corrosion.

[0059] This invention is energy-saving and environmentally friendly: through efficient oil-water separation, most of the oil can be separated from wastewater, reducing resource waste. At the same time, the quality of the treated water is significantly improved, reducing environmental pollution.

[0060] The invention is easy to install and maintain: the multi-stage separation device is installed horizontally and at a height not higher than the water injection pipeline, avoiding damage to the device caused by seabed scraping; in addition, due to the use of standardized design and easy-to-disassemble components, the maintenance and repair of the device are made simpler and faster.

[0061] This invention enhances system safety: In water injection subsea pipeline systems, the presence of oil-water mixtures may cause corrosion and blockage of pipelines and equipment; by employing a multi-stage oil-water separation device, these potential risks are reduced through effective separation of oil, thereby improving the safety and stability of the entire system.

[0062] This invention enables intelligent control: by using a PLC to control the opening of the ball valve, intelligent management of the status of oily waste collection and water injection pipeline maintenance can be achieved; this not only improves the convenience of operation, but also ensures the stable operation and timely response of the device under different working conditions.

[0063] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first," "second," etc., 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. Thus, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0064] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" 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 will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0065] The applicant declares that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A multi-stage oil-water separation device for a water injection subsea pipeline, characterized in that: It includes multiple sets of primary oil skimmers, multiple sets of secondary oil skimmers, and a secondary oil collection pipe (9) connected to the outlet of the multiple sets of secondary oil skimmers; the primary oil skimmers are installed on the water injection subsea pipeline (1), the outlet of the primary oil skimmers is connected to the inlet of the secondary oil skimmers, the outlet of the secondary oil skimmers is connected to the secondary oil collection pipe (9), and the outlet of the secondary oil collection pipe (9) is connected to the crude oil transport pipe (2). The primary oil skimming device includes two sets of primary oil skimmers and a primary oil collection pipe (3) with both ends connected to the outlets of the two sets of primary oil skimmers respectively. The two sets of primary oil skimmers are symmetrically arranged with the primary oil collection pipe (3) as the center. The primary oil skimmer includes a water injection subsea pipeline connecting pipe (4), a primary oil skimming pipe (5) that is vertically connected to the water injection subsea pipeline connecting pipe (4) on the horizontal plane, and a primary oil transport pipe (6) that is connected to the primary oil skimming pipe (5). The outer diameter of the primary oil collection pipe (3) is 1 / 5 to 1 / 6 of the outer diameter of the water injection subsea pipe (1); The length of the water injection subsea pipe (1) between the two sets of primary oil skimmers in the primary oil skimmer device is 450mm~550mm; the center distance between the two sets of primary oil skimmers is 650~750mm. The connection end of the first-stage oil skimmer (5) and the water injection subsea pipeline connecting pipe (4) is located at the upper part of the water injection subsea pipeline connecting pipe (4), and the end face of the connection end of the first-stage oil skimmer (5) and the water injection subsea pipeline connecting pipe (4) is a slope, and the angle between the end face of the slope and the cross-section of the first-stage oil skimmer (5) is 58°~62°. The spacing between adjacent secondary skimmers is the same as the spacing between two sets of primary skimmers in the primary skimmer device; the secondary skimmer includes a primary oil collection pipe connecting pipe (10), a secondary skimmer pipe (11) that is vertically connected to the primary oil collection pipe connecting pipe (10) on the horizontal plane, and a secondary oil delivery pipe (12) that is connected to the secondary skimmer pipe (11). The outer diameter of the secondary oil collection pipe (9) is 1 / 4 to 1 / 5 of the outer diameter of the primary oil collection pipe (3).

2. The multi-stage oil-water separation device for subsea pipelines according to claim 1, characterized in that: The inner and outer diameters of the primary oil collection pipe (3) and the primary oil transmission pipe (6) are the same; the water injection subsea pipeline connecting pipe (4) is coaxially arranged with the water injection subsea pipeline (1) and has the same roundness.

3. The multi-stage oil-water separation device for subsea pipelines according to claim 1, characterized in that: The water injection subsea pipeline connecting pipe (4) is connected to the water injection subsea pipeline (1) via a flange.

4. The multi-stage oil-water separation device for subsea pipelines according to claim 1, characterized in that: The primary skimming pipe (5) is connected to the water injection subsea pipeline (4) by welding.

5. The multi-stage oil-water separation device for subsea pipelines according to claim 1, characterized in that: The primary oil supply pipe (6) and the primary skimming pipe (5) are connected by a primary adapter ball valve (7), and the primary oil supply pipe (6) and the primary oil collection pipe (3) are connected by a primary elbow (8); the primary adapter ball valve (7) is connected to the primary oil supply pipe (6) and the primary skimming pipe (5) by a flange and is sealed by a metal spiral wound gasket to prevent liquid leakage; the primary elbow (8) is directly welded to the primary oil supply pipe (6) and the primary oil collection pipe (3); the primary elbow (8) is a 90° short radius elbow.

6. The multi-stage oil-water separation device for subsea pipelines according to claim 1, characterized in that: The number of secondary skimmers is the same as the number of primary oil collection pipes (3).

7. The multi-stage oil-water separation device for subsea pipelines according to claim 6, characterized in that: The primary oil collection pipe (10) is connected to the primary oil collection pipe (3) through a flange; the inner and outer diameters of the secondary oil collection pipe (9), the secondary skimming pipe (11) and the secondary oil transport pipe (12) are all the same.

8. The multi-stage oil-water separation device for subsea pipelines according to claim 1, characterized in that: The horizontal positions of the primary skimming pipe (5), primary oil pipeline (6), primary oil collection pipe (3), secondary oil collection pipe (9) and secondary oil pipeline (12) are all not higher than the horizontal position of the water injection subsea pipeline (1).

9. The multi-stage oil-water separation device for subsea pipelines according to claim 1, characterized in that: The primary oil collection pipe (3), the water injection subsea pipeline connecting pipe (4), the primary oil skimming pipe (5), the primary oil transport pipe (6), the primary elbow (8), the secondary oil collection pipe (9), the primary oil collection pipe connecting pipe (10), the secondary oil skimming pipe (11), the secondary oil transport pipe (12), and the secondary elbow (14) are all made of duplex stainless steel. The pipes are coated with primer and topcoat for corrosion protection. The primer is made of phenolic epoxy resin, and the topcoat is made of two-component solvent-free phenolic epoxy resin. The anti-corrosion coating material on the inner wall of the pipe is glass flake paint.

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