Multistage oil-water separation device for water injection subsea pipeline

Abstract

The invention discloses a multistage oil-water separation device for a water injection subsea pipeline. The multistage oil-water separation device comprises a plurality of groups of first-stage oil skimming devices, a plurality of groups of second-stage oil skimmers and a second-stage oil gathering pipe communicated with outlets of the plurality of groups of second-stage oil skimmers, the first-stage oil skimming device is arranged on the water injection subsea pipeline, an outlet of the first-stage oil skimming device is communicated with an inlet of the second-stage oil skimming device, an outlet of the second-stage oil skimming device is communicated with the second-stage oil gathering pipe, and an outlet of the second-stage oil gathering pipe is communicated with the crude oil conveying pipe. The manufacturing process is simple, operation is convenient, equipment energy consumption increase caused by moving equipment and the like is avoided, the service life is long, oil-water separation and oil content reduction in the water injection subsea pipeline can be achieved through the pressure difference between the pipelines, and therefore the quality of reinjection water is further improved, and damage of oil contained in the reinjection water to a bottom layer is reduced.

Description

Technical Field

[0001] The invention belongs to the field of oil, gas and water treatment, and in particular relates to a multi-stage oil-water separation device for a water injection sea pipe. Background Art

[0002] With the continuous development of offshore oil exploration and development technology, the scale of offshore oil field exploitation is expanding, and water injection sea pipe operation has become an important means to maintain oil field production. However, during the water injection process, since the water source may contain a certain amount of oil and other impurities, traditional water injection sea pipes will directly inject this part of oil and impurities into the formation, which will not only affect the water injection effect, but also may cause pollution to the formation, thereby affecting the exploitation efficiency and production safety of the oil field.

[0003] The patent with publication number CN 218530084U discloses a water injection filter for marine oil and gas fields. By adding mobile boxes, motors and other devices, the filter can be used to filter the reinjection water and improve the quality of the reinjection water. However, the patent has the problems of complex equipment, high energy consumption, short life and inability to remove oil from the reinjection water. Summary of the invention

[0004] The present 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 sea pipe.

[0005] The present invention is achieved through the following technical solutions:

[0006] A multi-stage oil-water separation device for a water-injected sea pipe comprises a plurality of groups of primary oil skimming devices, a plurality of groups of secondary oil skimmers and a secondary oil manifold connected to the outlets of the plurality of groups of secondary oil skimmers; the primary oil skimming device is arranged on the water-injected sea pipe, the outlet of the primary oil skimming device is connected to the inlet of the secondary oil skimming device, the outlet of the secondary oil skimming device is connected to the secondary oil manifold, and the outlet of the secondary oil manifold is connected to a crude oil transportation pipe.

[0007] In the above technical scheme, the first-level oil skimming device includes two groups of first-level oil skimmers and a first-level oil manifold whose two ends are respectively connected to the outlets of the two groups of first-level oil skimmers, and the two groups of first-level oil skimmers are symmetrically arranged with the first-level oil manifold as the center; the first-level oil skimmer includes a water injection sea pipe connecting pipe, a first-level oil skimming pipe vertically connected to the water injection sea pipe connecting pipe on a horizontal plane, and a first-level oil pipeline connected to the first-level oil skimming pipe.

[0008] In the above technical scheme, the inner and outer diameters of the first-level oil manifold and the first-level oil delivery pipe are the same; the outer diameter of the first-level oil manifold is 1 / 5 to 1 / 6 of the outer diameter of the water injection sea pipe connected thereto; the water injection sea pipe connecting pipe is coaxially arranged with the water injection sea pipe and has the same roundness; the length of the water injection sea pipe between the two groups of first-level skimmers in the first-level skimming device is 450 mm to 550 mm, preferably 500 mm; the center distance between the two groups of first-level skimmers is 650 to 750 mm.

[0009] In the above technical solution, the water injection sea pipe connecting pipe is connected to the water injection sea pipe through a flange.

[0010] In the above technical solution, the connecting end of the first-level skimming pipe and the water injection sea pipe connecting pipe is arranged at the upper part of the water injection sea pipe connecting pipe, and the end face of the connecting end of the first-level skimming pipe and the water injection sea pipe connecting pipe is an inclined surface, and the angle between the end face of the inclined surface and the cross section of the first-level skimming pipe is 58° to 62°, preferably 60°; the first-level skimming pipe and the water injection sea pipe connecting pipe are connected by welding.

[0011] In the above technical solution, the first-level oil delivery pipe is connected to the first-level oil skimming pipe through a first-level adapter ball valve, and the first-level oil delivery pipe is connected to the first-level oil collection pipe through a first-level elbow;

[0012] The first-level adapter ball valve is connected to the first-level oil delivery pipe and the first-level skimming pipe through flanges and is sealed by a metal spiral wound gasket to prevent liquid leakage;

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

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

[0015] In the above technical solution, the first-level oil manifold connecting pipe is connected to the first-level oil manifold through a flange; the inner and outer diameters of the second-level oil manifold, the second-level skimming pipe and the second-level oil delivery pipe are the same; the outer diameter of the second-level oil manifold is 1 / 4 to 1 / 5 of the outer diameter of the first-level oil manifold.

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

[0017] In the above technical scheme, the first-level oil manifold, water injection sea pipe connecting pipe, first-level skimming pipe, first-level oil pipeline, first-level elbow, second-level oil manifold, first-level oil manifold connecting pipe, second-level skimming pipe, second-level oil pipeline and second-level elbow are all made of duplex stainless steel, and the outside of the pipe is coated with primer and topcoat for corrosion protection. The primer uses phenolic epoxy resin type, and the topcoat uses two-component solvent-free phenolic epoxy type. The anti-corrosion coating material coated on the inner wall of the pipe is glass flake paint.

[0018] The beneficial effects of the present invention are:

[0019] The present invention provides a multi-stage oil-water separation device for water injection sea pipes, which has a simple manufacturing process, is easy to operate, has no moving equipment and the like to increase the energy consumption of the equipment, has a long service life, and can utilize the pressure difference between the pipelines themselves to achieve oil-water separation in the water injection sea pipes, reduce the oil content, thereby further improving the quality of reinjection water and reducing the damage of the oil content in the reinjection water to the bottom layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is a stereogram of the present invention;

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

[0022] in:

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

[0024] For ordinary technicians in this field, other relevant drawings can be obtained based on the above drawings without any creative work. DETAILED DESCRIPTION

[0025] In order to enable those skilled in the art to better understand the technical solution of the present invention, the technical solution of the present invention is further described below with reference to the accompanying drawings and through specific implementation methods.

[0026] like Figure 1 , 2 As shown, a multi-stage oil-water separation device for water injection sea pipe comprises a plurality of groups of primary oil skimmers, a plurality of groups of secondary oil skimmers and a secondary oil manifold 9 connected with the outlets of the plurality of groups of secondary oil skimmers; the primary oil skimmer is arranged on the water injection sea pipe 1, the outlet of the primary oil skimmer is connected with the inlet of the secondary oil skimmer, the outlet of the secondary oil skimmer is connected with the secondary oil manifold 9, and the outlet of the secondary oil manifold 9 is connected with the crude oil transportation pipe 2;

[0027] The primary oil skimming device comprises two groups of primary oil skimmers and a primary oil manifold 3 whose two ends are respectively connected to the outlets of the two groups of primary oil skimmers, and the two groups of primary oil skimmers are symmetrically arranged with the primary oil manifold 3 as the center;

[0028] The primary oil skimmer comprises a water injection sea pipe connecting pipe 4, a primary oil skimming pipe 5 vertically connected to the water injection sea pipe connecting pipe 4 on a horizontal plane, and a primary oil pipeline 6 connected to the primary oil skimming pipe 5;

[0029] The water injection sea pipe connecting pipe 4 is connected to the water injection sea pipe 1 through a flange;

[0030] The first-level oil collection pipe 3, the first-level oil delivery pipe 6 and the first-level oil collection pipe connecting pipe 10 have the same inner and outer diameters;

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

[0032] The water injection sea pipe connecting pipe 4 is coaxially arranged with the water injection sea pipe 1 and has the same roundness;

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

[0034] The connecting end of the first-level skimming pipe 5 and the water injection sea pipe connecting pipe 4 is arranged at the upper part of the water injection sea pipe connecting pipe 4, and the end face of the connecting end of the first-level skimming pipe 5 and the water injection sea pipe connecting pipe 4 is an inclined surface, and the angle between the end face of the inclined surface and the cross section of the first-level skimming pipe 5 is 58° to 62°, preferably 60°;

[0035] The first-level skimming pipe 5 is connected to the water injection sea pipe connecting pipe 4 by welding;

[0036] The first-level oil delivery pipe 6 is connected to the first-level skimming pipe 5 through a first-level adapter ball valve 7, and the first-level oil delivery pipe 6 is connected to the first-level oil collection pipe 3 through a first-level elbow 8;

[0037] The first-level adaptable ball valve 7 is connected to the first-level oil delivery pipe 6 and the first-level skimming pipe 5 through flanges and is sealed by a metal spiral wound gasket to prevent liquid leakage;

[0038] The primary elbow 8 is directly welded and fixed to the primary oil delivery pipe 6 and the primary oil collection pipe 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 manifolds 3;

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

[0041] The primary oil manifold connecting pipe 10 is connected to the primary oil manifold 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 collecting pipe 9 is 1 / 4 to 1 / 5 of the outer diameter of the primary oil collecting pipe 3;

[0044] The first-level oil collection pipe connecting pipe 10 is coaxially arranged with the first-level oil collection pipe 3 and has the same roundness;

[0045] The spacing between the adjacent secondary oil skimmers is the same as the spacing between two groups of primary oil skimmers in the primary oil skimming device;

[0046] The connecting end of the secondary skimming pipe 11 and the primary oil collecting pipe connecting pipe 10 is arranged at the upper part of the primary oil collecting pipe connecting pipe 10, and the end surface of the connecting end of the secondary skimming pipe 11 and the primary oil collecting pipe connecting pipe 10 is an inclined surface, and the angle between the end surface of the inclined surface and the cross section of the secondary skimming pipe 11 is 58° to 62°, preferably 60°;

[0047] The secondary oil skimming pipe 11 is connected to the primary oil collecting pipe connecting pipe 10 by welding;

[0048] The secondary oil delivery pipe 12 is connected to the secondary oil skimming pipe 11 through a secondary adapter ball valve 13, and the secondary oil delivery pipe 12 is connected to the secondary oil collection pipe 9 through a secondary elbow 14;

[0049] The secondary adaptable ball valve 13 is connected to the secondary oil delivery pipe 12 and the secondary oil skimming pipe 11 through flanges and sealed by a metal spiral wound gasket to prevent liquid leakage;

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

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

[0052] The horizontal positions of the first-level skimmer pipe 5, the first-level oil delivery pipe 6, the first-level oil manifold 3, the second-level oil manifold and the second-level oil delivery pipe 12 are not higher than the horizontal position of the water injection sea pipe 1 to avoid damage to the device caused by scratches on the seabed;

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

[0054] The ball valve bodies of the first-stage adaptable ball valve 7 and the second-stage adaptable ball valve 13 are made of duplex stainless steel, the valve core material is 316SS, and the surface anti-corrosion requirements are the same as those of the pipeline;

[0055] The first-stage adaptable ball valve 7 and the second-stage adaptable ball valve 13 adopt PLC to control the valve opening, so as to ensure timely transmission of dirty oil and shutdown of the water injection sea pipe under maintenance.

[0056] The present invention realizes efficient oil-water separation: when the produced water in the water injection sea pipe is transported from the platform to the seabed, part of the oil phase floats on the upper part of the water injection pipe due to aggregation and density difference. The multi-stage skimming device is used in conjunction with each other, and each stage of the skimming device adopts a design of multiple groups of skimmers, thereby utilizing the pressure difference in the water injection sea pipe and the crude oil transportation pipeline to realize multi-stage oil-water separation in the oil-water mixture; each stage further improves the efficiency of oil-water separation, so that the oil content in the final reinjected water is significantly reduced;

[0057] The present invention has a compact structure and occupies little space: the entire device adopts a compact design, and the skimming devices and pipelines at all levels are carefully laid out, so that the overall space occupied is small, which is convenient for installation and deployment in limited seabed space;

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

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

[0060] The present invention is easy to install and maintain: the multi-stage separation device is installed horizontally, and the installation height is not higher than the water injection sea pipe, which avoids damage to the device caused by seabed scratches; in addition, due to the use of standardized design and easily disassembled parts, the maintenance and overhaul of the device becomes simpler and faster;

[0061] The present invention improves system safety: In a water injection sea pipe system, the presence of an oil-water mixture may cause damage such as corrosion and blockage to pipes and equipment; the use of a multi-stage oil-water separation device effectively separates the oil, thereby reducing these potential risks and improving the safety and stability of the entire system.

[0062] The present invention can realize intelligent control: by adopting PLC to control the opening of the ball valve, intelligent management of the maintenance status of the waste oil collection and water injection sea pipe can be realized; 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 the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and the like are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, features defined as "first", "second", and the like may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0064] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood by specific circumstances.

[0065] The applicant declares that the above is only a specific implementation mode 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 thought of by those skilled in the art within the technical scope disclosed by the present invention shall fall within the protection scope and disclosure scope of the present invention.

Claims

1. A multi-stage oil-water separation device for water injection sea pipe, characterized in that: The invention comprises a plurality of groups of primary oil skimming devices, a plurality of groups of secondary oil skimmers and a secondary oil collection pipe (9) connected to the outlets of the plurality of groups of secondary oil skimmers; the primary oil skimming devices are arranged on a water injection sea pipe (1); the outlets of the primary oil skimming devices are connected to the inlets of the secondary oil skimming devices; the outlets of the secondary oil skimming devices are connected to the secondary oil collection pipe (9); and the outlets of the secondary oil collection pipe (9) are connected to a crude oil transportation pipe (2).

2. The multi-stage oil-water separation device for water injection sea pipe according to claim 1 is characterized in that: The primary oil skimmer device comprises two groups of primary oil skimmers and a primary oil collection pipe (3) whose two ends are respectively connected to the outlets of the two groups of primary oil skimmers, and the two groups of primary oil skimmers are symmetrically arranged with the primary oil collection pipe (3) as the center; the primary oil skimmer comprises a water injection sea pipe connecting pipe (4), a primary oil skimming pipe (5) vertically connected to the water injection sea pipe connecting pipe (4) on a horizontal plane, and a primary oil delivery pipe (6) connected to the primary oil skimming pipe (5).

3. The multi-stage oil-water separation device for water injection sea pipe according to claim 2 is characterized in that: The first-level oil collection pipe (3) and the first-level oil delivery pipe (6) have the same inner and outer diameters; the outer diameter of the first-level oil collection pipe (3) is 1 / 5 to 1 / 6 of the outer diameter of the water injection sea pipe (1); the water injection sea pipe connecting pipe (4) is coaxially arranged with the water injection sea pipe (1) and has the same roundness; the length of the water injection sea pipe (1) between the two groups of first-level oil skimmers in the first-level oil skimming device is 450 mm to 550 mm; and the center distance between the two groups of first-level oil skimmers is 650 to 750 mm.

4. The multi-stage oil-water separation device for water injection sea pipe according to claim 2 is characterized in that: The water injection sea pipe connecting pipe (4) is connected to the water injection sea pipe (1) via a flange.

5. The multi-stage oil-water separation device for water injection sea pipe according to claim 2 is characterized in that: The connecting end of the first-level skimming pipe (5) and the water injection sea pipe connecting pipe (4) is arranged on the upper part of the water injection sea pipe connecting pipe (4), and the end face of the connecting end of the first-level skimming pipe (5) and the water injection sea pipe connecting pipe (4) is an inclined surface, and the angle between the end face of the inclined surface and the cross section of the first-level skimming pipe (5) is 58° to 62°; the first-level skimming pipe (5) and the water injection sea pipe connecting pipe (4) are connected by welding.

6. The multi-stage oil-water separation device for water injection sea pipe according to claim 2 is characterized in that: The first-level oil delivery pipe (6) is connected to the first-level oil skimming pipe (5) through a first-level adaptor ball valve (7), and the first-level oil delivery pipe (6) is connected to the first-level oil collection pipe (3) through a first-level elbow (8); the first-level adaptor ball valve (7) is connected to the first-level oil delivery pipe (6) and the first-level oil skimming pipe (5) through a flange, and is sealed by a metal spiral wound gasket to prevent liquid leakage; the first-level elbow (8) is directly welded and fixed to the first-level oil delivery pipe (6) and the first-level oil collection pipe (3); the first-level elbow (8) is a 90° short radius elbow.

7. The multi-stage oil-water separation device for water injection sea pipe according to claim 1 is characterized by: The number of the secondary oil skimmers is the same as the number of the primary oil manifold (3); the spacing between adjacent secondary oil skimmers is the same as the spacing between two groups of primary oil skimmers in the primary oil skimming device; the secondary oil skimmer comprises a primary oil manifold connecting pipe (10), a secondary oil skimming pipe (11) vertically connected to the primary oil manifold connecting pipe (10) on a horizontal plane, and a secondary oil delivery pipe (12) connected to the secondary oil skimming pipe (11).

8. The multi-stage oil-water separation device for water injection sea pipe according to claim 7 is characterized in that: The first-level oil collection pipe connecting pipe (10) is connected to the first-level oil collection pipe (3) through a flange; the inner and outer diameters of the second-level oil collection pipe (9), the second-level oil skimming pipe (11) and the second-level oil delivery pipe (12) are all the same; the outer diameter of the second-level oil collection pipe (9) is 1 / 4 to 1 / 5 of the outer diameter of the first-level oil collection pipe (3).

9. The multi-stage oil-water separation device for water injection sea pipe according to claim 1, characterized in that: The horizontal positions of the first-level oil skimming pipe (5), the first-level oil delivery pipe (6), the first-level oil collection pipe (3), the second-level oil collection pipe and the second-level oil delivery pipe (12) are not higher than the horizontal position of the water injection sea pipe (1).

10. The multi-stage oil-water separation device for water injection sea pipe according to claim 1, characterized in that: The first-level oil collection pipe (3), the water injection sea pipe connecting pipe (4), the first-level skimming pipe (5), the first-level oil pipeline (6), the first-level elbow (8), the second-level oil collection pipe (9), the first-level oil collection pipe connecting pipe (10), the second-level skimming pipe (11), the second-level oil pipeline (12) and the second-level elbow (14) are all made of duplex stainless steel. The outside of the pipe is coated with a primer and a 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 coated on the inner wall of the pipe is a glass flake paint.

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