Underwater wave-shaped tubular separator for marine oil and gas production and working method thereof

Abstract

The present invention discloses an underwater wave-shaped tubular separator and a working method for marine oil and gas exploitation, which relates to the technical field of marine oil and gas exploitation separation devices, and includes a shunt pipe and a buffer pipe arranged in parallel, wherein the shunt pipe is located above the buffer pipe, and the shunt pipe and the buffer pipe are connected through a separation pipe; one end of the shunt pipe is connected to an inlet pipe, and the other end is connected to a gas phase outlet pipe; one end of the buffer pipe is connected to a separation pipe, and the other end is connected to a liquid phase outlet pipe; the underwater wave-shaped tubular separator is suitable for underwater high-pressure environments, and has a compact structure, small footprint, strong pressure bearing capacity, high separation efficiency, and can flexibly adjust the processing capacity through series-parallel combination. The equipment has the advantages of simple installation and maintenance, low manufacturing and maintenance costs, strong adaptability and long service life, and provides a strong guarantee for the economic and safe exploitation of deepwater oil fields.

Description

Technical Field

[0001] The invention relates to the technical field of marine oil and gas exploitation separation devices, and in particular to an underwater wave-shaped tubular separator for marine oil and gas exploitation and a working method thereof. Background Art

[0002] As the resources of onshore and shallow-water oil and gas fields are gradually depleted, developing medium- and deep-water oil and gas fields and utilizing the abundant oil and gas resources on the seabed have become effective solutions to alleviate energy shortages. Oil production is shifting from onshore and shallow-water areas to medium- and deep-water areas. However, the development of offshore oil and gas fields currently faces challenges such as low reservoir pressure and high wellhead back pressure. These problems have, to a certain extent, affected the efficient, economical and safe development of offshore oil and gas fields.

[0003] In order to effectively solve the above problems, underwater separation technology came into being. The underwater separator can efficiently and instantly separate oil, gas and water, and directly inject the separated water phase back into the formation to maintain the formation pressure balance, while reducing the wellhead back pressure, improving the oil and gas recovery rate and fluid transportation efficiency, and promoting the continuous growth of marine oil and gas resource production. However, most of the existing seabed separators use a large horizontal gravity separator structure. This structure has a large pressure area on the seabed, resulting in greater pressure. Therefore, the separator of this structure often needs to adopt a thick shell design in the deep water high pressure environment, which not only requires special manufacturing processes and high costs, but also brings a series of problems such as large size, heavy weight, high investment, and difficult maintenance of the separator. Summary of the invention

[0004] In view of the problems existing in the prior art, the present invention provides an underwater wave-shaped tubular separator and working method for marine oil and gas exploitation. The wave-shaped separation pipeline is used to separate multiphase fluids, which can effectively achieve gas-liquid separation; the bottom buffer pipe provided can not only ensure the reliability and efficiency of separation, but also serve as a flushing pipeline to prevent solid deposition. The device is not only suitable for deepwater environments, but also overcomes the problems of large size, heavy weight, and high cost of traditional horizontal separators. It has the advantages of compact structure, low cost, and high separation efficiency. The device is also suitable for land environments.

[0005] The technical solution of the present invention is as follows:

[0006] In a first aspect of the present invention, there is provided an underwater wave-shaped tubular separator for marine oil and gas production, comprising a shunt pipe and a buffer pipe arranged in parallel, wherein the shunt pipe is located above the buffer pipe, and the shunt pipe and the buffer pipe are connected via a separation pipe;

[0007] The separation pipeline is wavy, including a V-shaped separation pipeline and an A-shaped separation pipeline, the V-shaped separation pipeline and the A-shaped separation pipeline are arranged at intervals, and adjacent V-shaped separation pipelines and A-shaped separation pipelines share a pipeline, and the upper parts of the two pipelines of the A-shaped separation pipeline are connected through a cross guide pipe;

[0008] One end of the diversion pipeline is connected to the inlet pipeline, and the other end is connected to the gas phase outlet pipeline; one end of the buffer pipeline is connected to the separation pipeline, and the other end is connected to the liquid phase outlet pipeline.

[0009] In some embodiments of the present invention, a set angle is formed between two adjacent pipes in the separation pipe, and the bottom of the V-shaped separation pipe is connected to the buffer pipe through a contraction pipe.

[0010] In some embodiments of the present invention, the diversion pipes and buffer pipes are arranged in multiple groups in parallel or in series or in a combination of series and parallel.

[0011] In some embodiments of the present invention, the inlet pipeline is connected to a multiphase flow produced liquid pipeline, and the gas phase outlet pipeline and the liquid phase outlet pipeline are both connected to an offshore floating production storage and offloading device.

[0012] In some embodiments of the present invention, the diameter of the diversion pipe and the diameter of the separation pipe are both larger than the diameter of the buffer pipe, and the diameter of the separation pipe is larger than the diameter of the cross-guiding pipe.

[0013] In some embodiments of the present invention, the buffer pipe is arranged directly below the diversion pipe, and the cross-guiding pipe is arranged in parallel with the diversion pipe and the buffer pipe.

[0014] In a second aspect of the present invention, there is provided a method for operating an underwater wave-shaped tubular separator for marine oil and gas production, comprising the following steps:

[0015] The multiphase produced fluid flows from the inlet pipe into the diversion pipe. The multiphase produced fluid is diverted during the flow, with part of it entering the separation pipe and the other part continuing to flow forward along the diversion pipe.

[0016] During the flow of multiphase produced fluid, gas and liquid are separated according to the density difference. Part of the fluid in the separation pipeline flows directly to the bottom of the separation pipeline, and the other part of the fluid flows to the adjacent separation pipeline through the cross-guiding pipe and then flows to the bottom.

[0017] The liquid separated in the separation pipe gathers in the buffer pipe at the bottom and flows out through the liquid phase outlet pipe, and the gas flows out directly from the gas phase outlet pipe at the top.

[0018] In some embodiments of the present invention, part of the fluid in the separation pipe enters the buffer tube through the contraction tube.

[0019] In some embodiments of the present invention, the buffer pipe is used as a sand flushing pipeline, and the diameter change of the sudden reduction pipe and the buffer pipe with a smaller diameter are used to increase the liquid flow rate to carry the solid out.

[0020] In some embodiments of the present invention, the gas flowing out of the gas phase outlet pipeline and the liquid flowing out of the liquid phase outlet pipeline are transported to an offshore floating production storage and offloading unit.

[0021] One or more technical solutions of the present invention have the following beneficial effects:

[0022] (1) The underwater wave-shaped tubular separator provided by the present invention adopts a pipeline structure design as a whole. Under the same operating pressure, the wall thickness requirement of the pipeline separator is much smaller than that of the horizontal gravity separator. At the same time, the tubular separator can be manufactured with standard pipe sizes, which is easy to manufacture, greatly reducing the manufacturing cost while ensuring quality. The separation pipe is designed in a wave shape, making the underwater separator structure more compact and half the length of the same type of tubular separator, greatly reducing the installation space and floor area required for the separator.

[0023] (2) The underwater wave-shaped tubular separator provided by the present invention utilizes the principle of gravity sedimentation to perform efficient gas-liquid separation on the seabed. The separated gas flows out through the gas phase outlet pipe at the top, and the separated liquid passes through the buffer pipe and is discharged through the liquid phase outlet pipe. In addition, the buffer pipe at the bottom of the separator can also be used as a sand flushing pipeline. The small diameter increases the liquid flow rate, thereby better carrying out solids, preventing solid deposition, and ensuring the smooth operation of the separator. The device of the present invention has a compact structure, low cost, and easy installation. Compared with the existing underwater horizontal separators, it has a better structural design and ensures excellent separation efficiency.

[0024] (3) The underwater wavy tube separator provided by the present invention has no internal components inside the diversion pipe and the separation pipe, thereby ensuring the smooth flow of multiphase fluid; the large-diameter pipe design ensures sufficient flow and reduces the pressure accumulation in this area, thereby avoiding the impact of the fluid on the separation pipe; in addition, the separation pipe is distributed in a wavy shape ("VA" type), and this structure can adjust the incoming liquid flow rate to avoid the impact of the fluid on the separation pipe. At the same time, the larger pipe diameter provides a more spacious fluid channel; the small-diameter cross-guide pipes between adjacent separation pipes ensure the smoothness of the flow and avoid slugging; when the fluid flows in the wavy separation pipe, it circulates upward and downward, so that the residence time of the fluid is greater than that of the standard separator, thereby improving the separation efficiency.

[0025] (4) In the underwater wave-shaped tubular separator provided by the present invention, the buffer pipe has a smaller diameter than the diversion pipe and the separation pipe, which can increase the liquid phase flow rate, help the fluid pass more smoothly, and avoid unnecessary deposition or blockage; at the same time, the buffer pipe can be used as a sand flushing pipeline, and the accelerated liquid can better carry sand and prevent solids from depositing at the bottom of the separation pipe, thereby reducing the risk of blockage and the wear of the separator by solids such as gravel.

[0026] (5) The underwater wave-shaped tubular separator provided by the present invention can be designed with different wave distances and wave heights according to specific application scenarios. The separator as a whole adopts a modular design, and multiple tubular separators can be freely combined in series or in parallel to adapt to different flow rates and gas-oil ratios; the modular operation is simple and convenient, and can be adjusted autonomously according to different period conditions on site. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic diagram of the overall structure of the underwater wave-shaped tubular separator for marine oil and gas production of the present invention;

[0028] Figure 2 It is a structural schematic diagram of the separation pipeline of the present invention;

[0029] Figure 3 It is a schematic diagram of the underwater wave-shaped tubular separators of the present invention when they are connected in series;

[0030] Figure 4 It is a schematic diagram of the underwater wave-shaped tubular separators of the present invention when they are connected in parallel;

[0031] Figure 5 It is a schematic diagram of the fluid flow direction when the underwater wave-shaped tube separator of the present invention is working.

[0032] In the figure: 1. Inlet pipe; 2. Diversion pipe; 3. Gas phase outlet pipe; 4. Separation pipe; 41. V-type separation pipe; 42. A-type separation pipe; 43. Cross guide pipe; 44. Contraction pipe; 5. Buffer pipe; 6. Liquid phase outlet pipe; 7. Underwater wave-shaped tubular separator; 8. Centrifugal pump. DETAILED DESCRIPTION

[0033] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0034] Example 1

[0035] In a typical embodiment of the present invention, an underwater wave-shaped tubular separator for marine oil and gas production is provided. Figure 1 and Figure 2As shown, it includes a shunt pipe 2 and a buffer pipe 5 arranged in parallel, the shunt pipe 2 is located above the buffer pipe 5, and the shunt pipe 2 and the buffer pipe 5 are connected via a separation pipe 4;

[0036] The separation pipeline 4 is wavy, including a V-shaped separation pipeline 41 and an A-shaped separation pipeline 42. The V-shaped separation pipeline 41 and the A-shaped separation pipeline 42 are arranged at intervals, and adjacent V-shaped separation pipelines 41 and A-shaped separation pipelines 42 share a pipeline. The upper parts of the two pipelines of the A-shaped separation pipeline 42 are connected through a cross guide pipe 43.

[0037] One end of the diversion pipeline 2 is connected to the inlet pipeline 1 , and the other end is connected to the gas phase outlet pipeline 3 ; one end of the buffer pipeline 5 is connected to the separation pipeline 4 , and the other end is connected to the liquid phase outlet pipeline 6 .

[0038] In this embodiment, there is a certain angle between two adjacent pipes in the separation pipe 4, so that the separation pipe 4 is distributed in a wave-like ("VA" type), and the wave-like separation pipe includes a V-type separation pipe 41, an A-type separation pipe 42 and a cross-guiding pipe 43, wherein the two adjacent pipes of the A-type separation pipe 42 are designed at a certain angle and connected by a cross-guiding pipe 43 with a small diameter; the bottom of the V-type separation pipe 41 is connected to the buffer pipe 5 through a sudden contraction pipe 44. The sudden contraction structure can adjust the flow rate of the incoming liquid to avoid the deposition of solids at the bottom of the separation pipe by connecting to the bottom of the V-type separation pipe 41 through a section of the sudden contraction pipe 44; at the same time, the diameter of the diversion pipe 2 is larger than the diameter of the buffer pipe 5, and the small diameter design of the buffer pipe 5 ensures that the flow rate of the fluid is accelerated when passing through the bottom horizontal buffer pipe, thereby helping the fluid to carry solids out of the separator and avoid the accumulation of sand particles.

[0039] In this embodiment, the inlet pipe 1, the branch pipe 2 and the gas phase outlet pipe 3 are connected in sequence and arranged horizontally. The diameters of the inlet pipe 1, the branch pipe 2 and the gas phase outlet pipe 3 are the same and all relatively large. The larger diameter of the inlet pipe 1 ensures sufficient inlet flow, and the larger diameter of the branch pipe 2 ensures the stability of the flow and reduces the pressure accumulation in this area. The gas with lower density passes through the branch pipe 2 to reach the gas phase outlet pipe 3 and flows out.

[0040] Furthermore, the buffer pipe 5 is arranged directly below the diversion pipe 2, the cross-guiding pipe 43 is arranged in parallel with the diversion pipe 2 and the buffer pipe 5, the two adjacent pipes of the A-type separation pipe 42 are connected through the cross-guiding pipe 43, the diameter of the separation pipe 4 is larger than the diameter of the cross-guiding pipe 43, and the small diameter cross-guiding pipe 43 ensures the smoothness of the flow and avoids the slugging phenomenon. The inlet of the buffer pipe 5 is connected to the bottom of the first V-shaped separation pipe 41, and the outlet is connected to the liquid phase outlet pipe 6. The liquid with a higher density flows out through the liquid phase outlet pipe 6 after adjusting the flow rate through the buffer pipe 5.

[0041] like Figure 3 and Figure 4 As shown, the diversion pipeline 2 and the buffer pipeline 5 are arranged in multiple groups in parallel or in series or in a combination of series and parallel. The separator adopts a modular design as a whole, and can be freely combined in series or in parallel to adapt to different flow rates and gas-oil ratios; the modular operation is simple and convenient, and can be adjusted autonomously according to different period conditions on site.

[0042] In this embodiment, the inlet pipeline 1 is connected to the multiphase flow produced liquid pipeline, and the gas phase outlet pipeline 3 and the liquid phase outlet pipeline 6 are both connected to an offshore floating production storage and offloading unit (FPSO).

[0043] like Figure 5 As shown, the working principle of the underwater wave-shaped tubular separator 7 provided in this embodiment is as follows:

[0044] The multiphase produced liquid flows from the inlet pipe 1 into the diversion pipe 2. The multiphase produced liquid is diverted during the flow, with part of the liquid entering the separation pipe 4 and the other part continuing to flow forward along the diversion pipe 2.

[0045] The multiphase produced fluid undergoes gas-liquid separation according to the density difference during the flow process. Part of the fluid in the separation pipe 4 flows directly to the bottom of the separation pipe, and the other part of the fluid flows to the adjacent separation pipe through the cross-guiding pipe 43 and then flows to the bottom.

[0046] The liquid separated in the separation pipe 4 is gathered in the buffer pipe at the bottom and flows out through the liquid phase outlet pipe 6 under the action of the centrifugal pump 8, and the gas flows out directly from the gas phase outlet pipe 3 at the top.

[0047] The separator uses gravity sedimentation, that is, it uses the density difference of each phase to make the liquid in the multiphase fluid settle to the bottom and the gas rise to the top under the action of gravity, completing the gas-liquid separation, and discharge them through different outlets and transport them to the offshore floating production storage and offloading unit (FPSO).

[0048] Example 2

[0049] In a typical embodiment of the present invention, a working method of an underwater wave-shaped tubular separator for marine oil and gas production is provided, comprising the following steps:

[0050] The multiphase produced fluid flows from the inlet pipe into the diversion pipe. The multiphase produced fluid is diverted during the flow, with part of it entering the separation pipe and the other part continuing to flow forward along the diversion pipe.

[0051] During the flow of multiphase produced fluid, gas and liquid are separated according to the density difference. Part of the fluid in the separation pipeline flows directly to the bottom of the separation pipeline, and the other part of the fluid flows to the adjacent separation pipeline through the cross-guiding pipe and then flows to the bottom.

[0052] The liquid separated in the separation pipe gathers in the buffer pipe at the bottom and flows out through the liquid phase outlet pipe, and the gas flows out directly from the gas phase outlet pipe at the top.

[0053] Furthermore, part of the fluid in the separation pipe enters the buffer tube through the sudden contraction tube.

[0054] Furthermore, the buffer pipe can also be used as a sand flushing pipeline, and the diameter change of the sudden reduction pipe and the buffer pipe with a smaller diameter are used to increase the liquid flow rate to carry the solid out.

[0055] Furthermore, the gas flowing out of the gas phase outlet pipeline and the liquid flowing out of the liquid phase outlet pipeline are transported to an offshore floating production storage and offloading unit.

[0056] Although the above describes the specific implementation mode of the present invention in conjunction with the accompanying drawings, it is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art on the basis of the technical solution of the present invention without creative work are still within the scope of protection of the present invention.

Claims

1. An underwater wave-shaped tubular separator for marine oil and gas production, characterized in that: It comprises a shunt pipe and a buffer pipe arranged in parallel, wherein the shunt pipe is located above the buffer pipe, and the shunt pipe and the buffer pipe are connected via a separation pipe; The separation pipeline is wavy, including a V-shaped separation pipeline and an A-shaped separation pipeline, the V-shaped separation pipeline and the A-shaped separation pipeline are arranged at intervals, and adjacent V-shaped separation pipelines and A-shaped separation pipelines share a pipeline, and the upper parts of the two pipelines of the A-shaped separation pipeline are connected through a cross guide pipe; One end of the diversion pipeline is connected to the inlet pipeline, and the other end is connected to the gas phase outlet pipeline; one end of the buffer pipeline is connected to the separation pipeline, and the other end is connected to the liquid phase outlet pipeline; the buffer pipeline can be used as a sand flushing pipeline to prevent solid deposition; No internal components are arranged inside the diversion pipeline and the separation pipeline; A set angle is formed between two adjacent pipes in the separation pipe, and the bottom of the V-shaped separation pipe is connected to the buffer pipe through a sudden contraction pipe; The diameter of the diversion pipeline and the diameter of the separation pipeline are both larger than the diameter of the buffer pipeline, and the diameter of the separation pipeline is larger than the diameter of the cross-guiding pipe; The buffer pipeline is arranged directly below the diversion pipeline, and the cross flow guide pipe is arranged in parallel with the diversion pipeline and the buffer pipeline; The small-diameter cross-flow pipes between adjacent separation pipes ensure smooth flow to avoid slugging; when the fluid flows in the wave-shaped separation pipe, it circulates upward and downward, making the fluid's residence time greater than that of the standard separator, thereby improving the separation efficiency.

2. The underwater wave-shaped tubular separator for marine oil and gas production according to claim 1, characterized in that: The shunt pipes and buffer pipes are arranged in multiple groups in parallel or in series or in a combination of series and parallel.

3. The underwater wave-shaped tubular separator for marine oil and gas production according to claim 1, characterized in that: The inlet pipeline is connected to the multiphase flow produced liquid pipeline, and the gas phase outlet pipeline and the liquid phase outlet pipeline are both connected to the offshore floating production storage and offloading device.

4. A method for operating an underwater wave-shaped tubular separator for marine oil and gas production according to any one of claims 1 to 3, characterized in that: The following steps are involved: The multiphase produced fluid flows from the inlet pipe into the diversion pipe. The multiphase produced fluid is diverted during the flow, with part of it entering the separation pipe and the other part continuing to flow forward along the diversion pipe. During the flow of multiphase produced fluid, gas and liquid are separated according to the density difference. Part of the fluid in the separation pipeline flows directly to the bottom of the separation pipeline, and the other part of the fluid flows to the adjacent separation pipeline through the cross-guiding pipe and then flows to the bottom. The liquid separated in the separation pipe gathers in the buffer pipe at the bottom and flows out through the liquid phase outlet pipe, and the gas flows out directly from the gas phase outlet pipe at the top.

5. The working method of the underwater wave-shaped tubular separator for marine oil and gas production according to claim 4, characterized in that: Part of the fluid in the separation pipe enters the buffer tube through the sudden reduction tube.

6. The working method of the underwater wave-shaped tubular separator for marine oil and gas production according to claim 5, characterized in that: The buffer pipe is used as a sand flushing pipeline, and utilizes the diameter change of the sudden reduction pipe and the buffer pipe with a smaller diameter to increase the liquid flow rate to carry the solid out.

7. The working method of the underwater wave-shaped tubular separator for marine oil and gas production according to claim 4, characterized in that: The gas flowing out of the gas phase outlet pipeline and the liquid flowing out of the liquid phase outlet pipeline are transported to an offshore floating production storage and offloading unit.

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