Offshore high-water-content oil field old platform expansion process and key equipment

Abstract

The invention discloses key equipment for capacity expansion of an old platform of an offshore high-water-content oil field. Comprising a platform original first-stage three-phase separator, a platform original second-stage three-phase separator, a degassing desander, a platform natural gas treatment and recovery system, a platform oil-containing solid recovery system, a tubular vortex pre-dehydrator, a tubular vortex degreaser, a platform production water treatment and reinjection system, an exhaust pipe and a valve assembly. Degassing is completed through weak rotational flow and weight deposition formed by a tangential inlet, sand removal is completed through combination of secondary rotational flow formed by a flow stabilizing cylinder support and a flow adjusting component and an inclined plate, and it is guaranteed that follow-up tubular vortex water pre-diversion and a tubular degreaser work in the optimal working environment.

Description

Technical Field

[0001] This invention relates to the field of offshore oilfield produced fluid treatment and capacity expansion technology, and in particular to a capacity expansion process and key equipment for aging platforms in offshore high water-cut oilfields. Background Technology

[0002] Currently, most offshore oilfields in China are in the mid-to-late stages of development, with an average water cut of 90.3%, and some even reaching 98%, and the water cut is still rising. Increasing fluid production from older oilfields is an effective measure to ensure my country's energy supply. When maintaining a constant crude oil production, the trend of increasing fluid volume required for oilfield processing with rising water cut is as follows: Figure 1 As shown, when the water cut increases from 90% to 95%, the volume of extracted liquid doubles. Figure 5 As shown, the amount of liquid that needs to be treated increases with increasing water content.

[0003] Offshore oil production platforms are expensive per unit area, and the load-bearing capacity of many older platforms is nearing its limit. Therefore, the significant increase in produced fluid volume during the recovery and production of older oilfields presents a severe challenge to the platform's gathering and processing system. Addressing the dual constraints of space and load-bearing capacity on older offshore platforms, tubular separation technology—characterized by its small footprint, light weight, high efficiency, and synergistic effects—is an effective measure to solve the problem of rapidly increasing produced fluid on older platforms in high-water-cut oilfields without expanding the platform. However, with increasing production time, the formation becomes loosely cemented and experiences excessive production pressure differentials, leading to sand production. Increased sand content results in increased erosion of tubular separation equipment based on strong swirling mechanisms, reduced separator life, decreased separation efficiency, and even blockage of the tubular equipment.

[0004] Existing technologies all employ methods that enhance the use of three-phase separators in the platform. For example, patent publication number CN101852075A, "An Oil and Gas Gathering and Transportation Process Based on Offshore Marginal Oilfields," uses a two-stage conventional horizontal three-phase separator to complete oil-water separation. Publication number CN114164019A, "Offshore Oilfield Well Produced Fluid Dehydration Treatment System and Process," addresses the issue of increased processing fluid volume by adding electrode components to a conventional three-phase separator and utilizing electric field enhancement to improve the processing capacity of the conventional horizontal three-phase separator; the aqueous phase is treated using a hydrocyclone. Publication number CN118529818A, "A Process for Rapid Separation of Oilfield Produced Fluid," adds hydrophilic and oleophobic packing material to a conventional gravity settling tank, using this material to disperse the aggregation of oil particles and improve the separation performance of the three-phase separator.

[0005] The existing method using three separators is prone to negative impacts on the separation performance of tubular separators due to the increased sand content in the produced fluid during the middle and late stages of oilfield production. To address this issue, the patent CN109555511, "An Oil Well Sand Removal Device Based on Pulse Jet Technology and Cyclone Separation Mechanism," employs a static cyclone separator to complete degassing and sand removal, with both the liquid outlet and sand outlet located at the bottom outlet. However, it does not disclose specific measures for achieving liquid-sand separation.

[0006] The patent application CN209354117, titled "A Multi-Segment Broken Line Type Settling Degassing and Sand Removal Eccentric Gas Anchor," describes a gas-liquid-solid three-phase separation method using gravity settling with a bent channel inside the casing. However, this method is prone to incomplete sand removal.

[0007] The patent application CN104445681, titled "Spiral Three-Phase Medium Separator," modifies a conventional static hydrocyclone by adding an overflow outlet for venting and a spiral discharge mechanism in the middle of the underflow outlet. This is a strong cyclone venting and sand removal system. While the turbulence intensity of the fluid is high under strong cyclone conditions, it cannot avoid problems such as gas carrying liquid, liquid carrying gas, and sand carrying. In addition, under the action of strong cyclone, solids will also cause strong wear on the sand separator wall.

[0008] Therefore, there is an urgent need for a key piece of equipment for expanding the capacity of old platforms in offshore high water-cut oilfields. Summary of the Invention

[0009] One objective of this invention is to provide a key piece of equipment for expanding the capacity of aging platforms in offshore high water-cut oilfields. This equipment solves the problem of high turbulence intensity in strong swirling environments, which inevitably leads to gas-liquid carryover and liquid-gas and sand carryover. Another objective of this invention is to provide a capacity expansion process for aging platforms in offshore high water-cut oilfields. This process involves adding a degassing and desanding unit to the existing primary and secondary three-phase separators on the platform. Utilizing its own tubular structure, the expansion of aging offshore oilfield platforms is achieved, ensuring high separation efficiency even under complex conditions. This results in high-precision separation and overcomes the drawbacks of current platform separation equipment, such as large footprint and low separation efficiency.

[0010] The first aspect of this invention provides key equipment for expanding the capacity of an aging platform in a high water-cut offshore oilfield, including an existing primary three-phase separator, an existing secondary three-phase separator, a degassing and desanding device, a natural gas treatment and recovery system, an oil-containing solids recovery system, a tubular vortex pre-dehydrator, a tubular vortex oil separator, a production water treatment and reinjection system, an exhaust pipe, and valve assemblies. The existing primary three-phase separator and the existing secondary three-phase separator are connected. The existing primary three-phase separator is connected to the platform's produced fluid supply pipe. The tangential inlet pipe of the degassing and desanding device is used for the platform's produced fluid to enter. The exhaust pipe of the degassing and desanding device is connected to the platform's natural gas treatment and recovery system. The desanding and desanding device's sand discharge pipe is connected to the platform's oil-containing solids recovery system. The outlet pipe of the degassing and desanding device is connected to the tubular vortex pre-dehydrator. The pre-dehydrator, the tubular vortex oil separator, and the platform production water treatment reinjection system are connected in sequence. The platform's original primary three-phase separator and the platform's original secondary three-phase separator are respectively connected to the tubular vortex oil separator. The tubular vortex pre-dehydrator and the tubular vortex oil separator are respectively connected to the platform's original secondary three-phase separator. Valve assemblies are respectively provided between the platform's produced fluid supply pipe and the platform's original primary three-phase separator, between the degassing and desanding device and the platform's produced fluid supply pipe, between the degassing and desanding device and the tubular vortex pre-dehydrator, between the tubular vortex pre-dehydrator and the tubular vortex oil separator, between the tubular vortex pre-dehydrator and the platform's original secondary three-phase separator, between the tubular vortex oil separator and the platform's original secondary three-phase separator, and between the tubular vortex oil separator and the platform production water treatment reinjection system.

[0011] The aforementioned key equipment for expanding the capacity of old offshore high water-cut oilfield platforms, preferably, includes a degassing and desanding device further comprising a wire mesh demister, a separation tank body, a flow stabilizing cylinder degassing component, a liquid outlet pipe, and a desanding device. The separation tank body is a vertical tank-shaped structure, with a tangential liquid inlet pipe located above the side wall of the separation tank body. The wire mesh demister, the flow stabilizing cylinder degassing component, and the desanding device are distributed sequentially from top to bottom inside the separation tank body. The separation tank body and the flow stabilizing cylinder degassing component form a circulating space, allowing the platform's produced fluid to enter the circulating space through the tangential liquid inlet pipe, thereby forming a swirling flow. The exhaust pipe is located at the top of the separation tank body.

[0012] The aforementioned key equipment for expanding the capacity of old platforms in offshore high water-cut oilfields, preferably, includes a flow stabilizing cylinder degassing component comprising a flow stabilizing cylinder body and flow stabilizing cylinder support and flow regulating components disposed at the bottom of the cylinder body. This allows the liquid to flow downwards along the main body of the separator, and through the enhanced swirling flow of the flow stabilizing cylinder support and flow regulating components, the less dense gas phase converges towards the center of the flow stabilizing cylinder body, while the denser solids move outwards to the inner wall of the separator body and enter the desanding device. The liquid remains between the solid and gas phases and is discharged from the liquid outlet pipe.

[0013] The aforementioned key equipment for expanding the capacity of old offshore high water-cut oilfield platforms, preferably, includes a sand removal device comprising a sand settling inclined plate component, a conical head, and a sand discharge pipe arranged sequentially from top to bottom. The sand settling inclined plate component is positioned above the conical head, and the bottom of the conical head is connected to the sand discharge pipe. The sand discharge pipe is positioned at the bottom of the separation tank body, so that a portion of the denser solids deposit downwards along the inner wall of the separation tank body into the conical head and are discharged from the sand discharge pipe. Another portion of fine sand that does not sink to the bottom of the conical head flows upward with the liquid, encounters the inclined plate of the sand settling inclined plate component, aggregates on the inclined plate, slides down the inclined plate, sinks again into the conical head, and is discharged from the sand discharge pipe.

[0014] The aforementioned key equipment for expanding old offshore high water-cut oilfield platforms, preferably, includes a degassing and desanding device comprising a wire mesh demister, a separation tank body, a tangential inlet pipe, a flow stabilizing cylinder degassing component, an outlet pipe, and a desanding device. The separation tank body is a vertical tank-shaped structure. The tangential inlet pipe is located on the upper side wall of the separation tank body. The wire mesh demister, the flow stabilizing cylinder degassing component, and the desanding device are distributed sequentially from top to bottom inside the separation tank body. The separation tank body and the flow stabilizing cylinder degassing component form a circulating space, so that the platform's produced fluid enters the circulating space through the tangential inlet pipe to form a swirling flow. The exhaust pipe is located at the top of the separation tank body.

[0015] The aforementioned key equipment for expanding the capacity of old platforms in offshore high water-cut oilfields, preferably, includes a flow stabilizing cylinder degassing component comprising a flow stabilizing cylinder body and a flow stabilizing cylinder support and a flow regulating component disposed at the bottom of the cylinder body. The flow stabilizing cylinder support fixes the flow stabilizing cylinder degassing component to the main body of the separator tank, while simultaneously enabling the liquid to flow downwards along the main body of the separator tank. The flow regulating component enhances the swirling flow, causing the less dense gas phase to converge towards the center of the flow stabilizing cylinder body, while the denser solids move outwards to the inner wall of the separator tank body and enter the desanding device. The liquid remains between the solid and gas phases and is discharged from the liquid outlet pipe.

[0016] The aforementioned key equipment for expanding the capacity of old offshore high water-cut oilfield platforms, preferably, includes a sand removal device comprising a sand settling inclined plate component, a conical head, and a sand discharge pipe arranged sequentially from top to bottom. The sand settling inclined plate component is a hollow cone shape, with its small end opening upwards and its large end fixed above the conical head. The bottom of the conical head is connected to the sand discharge pipe, which is located at the bottom of the separation tank body. This allows a portion of high-density solids to deposit downwards along the inner wall of the separation tank body within the conical head and then be discharged through the sand discharge pipe. Another portion of fine sand that does not sink to the bottom of the conical head flows upwards with the liquid, encounters the inclined plate of the sand settling inclined plate component, aggregates on the inclined plate, slides down the inclined plate, sinks again into the conical head, and is discharged through the sand discharge pipe.

[0017] The second aspect of this invention provides a capacity expansion process for aging platforms in offshore high water-cut oilfields, including the aforementioned key equipment for expanding aging platforms in offshore high water-cut oilfields, specifically comprising the following steps: The produced fluid from the platform enters through the inlet of the degassing and desanding unit to complete the degassing and desanding of the produced fluid; The natural gas removed by the degassing and desanding device enters the platform's natural gas treatment and recovery system. The oily sand separated by the degassing and desanding device is discharged into the platform's oily solids recovery system. The produced fluid treated by the degassing and desanding device enters the tubular vortex pre-dehydrator, where a portion of water is separated by strong vortex flow. The remaining water and dehydrated crude oil enter the platform's original two-stage three-phase separator. The water extracted by the tubular vortex pre-dehydrator, the water from the platform's original first-stage three-phase separator and the water from the platform's original second-stage three-phase separator are all fed into the tubular vortex oil separator. After passing through a strong vortex, the production water is quickly de-oiled and meets the requirements of the platform's production water treatment system. The treated water phase is then discharged into the platform's production water treatment reinjection system. The oily wastewater recovered by the tubular vortex oil separator is mixed with the oil phase of the tubular vortex pre-dehydrator and discharged together into the platform's existing two-stage three-phase separator.

[0018] The beneficial effects are: In terms of process, this invention adopts tubular vortex oil removal technology. In terms of equipment, the vertical degassing and desanding device uses two weak swirling flows and shallow settling to quickly complete degassing and desanding. The total hydraulic residence time is only 1.06 minutes, which reduces the operating weight by 90% compared with conventional three-phase separators with hydraulic residence times of more than 10 minutes. Moreover, the device's own tubular structure can be used to expand the capacity of old offshore oilfield platforms in a piecemeal manner.

[0019] The degassing and sand removal device provided by this invention utilizes the weak swirling flow and weight deposition formed by the tangential inlet to complete degassing, and utilizes the secondary swirling flow and inclined plate combination formed by the flow stabilizing cylinder support and flow regulating components to complete sand removal, ensuring that the subsequent tubular vortex pre-water separator and tubular oil separator operate in the optimal working environment. Attached Figure Description

[0020] Figure 1 A process flow diagram for improving the efficiency and capacity of produced fluids from offshore platforms; Figure 2 This is an exterior view of a compact degassing and sand removal device. Figure 3 This is a cross-sectional view of the compact degassing and sand removal equipment. Figure 4 A three-dimensional model of the flow stabilizer and its support; Figure 5 This relates to the relationship between water content and the volume of liquid to be treated in the background technology.

[0021] In the picture: 1. The platform originally had a primary three-phase separator; 2. The platform originally had a secondary three-phase separator; 3. Degassing and sand removal device; 4. Platform natural gas processing and recovery system; 5. Platform oily solids recovery system; 6. Tubular vortex pre-dehydrator; 7. Tubular vortex oil separator; 8. Platform production water treatment reinjection system; 9. Exhaust pipe; 10. Wire mesh demister; 11. Separator body; 12. Tangential inlet pipe; 13. Flow stabilizer degassing component; 14. Outlet pipe; 15. Sand settling inclined plate component; 16. Conical head; 17. Sand discharge pipe; 18-1. Flow stabilizer support component; 18-2. Flow regulating component; 19-1, First valve; 19-2, Second valve; 19-3, Third valve; 19-4, Fourth valve; 19-5, Fifth valve; 19-6, Sixth valve; 19-7, Seventh valve. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0023] In the description of this invention, it should be noted that the terms "upper," "lower," etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the system or component 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 use of terms such as "first," "second," etc., to define components is merely for the convenience of distinguishing the aforementioned components; unless otherwise stated, these terms have no special meaning and should not be construed as indicating or implying relative importance.

[0024] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "setting," and "connection" 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 based on the specific circumstances.

[0025] This invention provides a key piece of equipment for expanding the capacity of an old offshore high-water-cut oilfield platform, including an existing primary three-phase separator, an existing secondary three-phase separator, a degassing and desanding device, a platform natural gas treatment and recovery system, a platform oil-containing solids recovery system, a tubular vortex pre-dehydrator, a tubular vortex oil separator, a platform production water treatment and reinjection system, an exhaust pipe, and valve assemblies. The existing primary three-phase separator and the existing secondary three-phase separator are connected. The existing primary three-phase separator (1) is connected to the platform's produced fluid supply pipe. The tangential inlet pipe of the degassing and desanding device is used for the platform's produced fluid to enter. The exhaust pipe of the degassing and desanding device is connected to the platform's natural gas treatment and recovery system. The desanding and desanding device's sand discharge pipe is connected to the platform's oil-containing solids recovery system. The outlet pipe of the degassing and desanding device is connected to the tubular vortex pre-dehydrator. The tubular vortex pre-dehydrator, the tubular vortex oil separator, and the platform production water treatment reinjection system are connected in sequence. The original primary three-phase separator and the original secondary three-phase separator of the platform are respectively connected to the tubular vortex oil separator. The tubular vortex pre-dehydrator and the tubular vortex oil separator are respectively connected to the original secondary three-phase separator of the platform. The valve assembly is provided between the produced fluid and the original primary three-phase separator of the platform, between the degassing and desanding device and the original primary three-phase separator of the platform, between the degassing and desanding device and the tubular vortex pre-dehydrator, between the tubular vortex pre-dehydrator and the original secondary three-phase separator of the platform, between the tubular vortex oil separator and the original secondary three-phase separator of the platform, and between the tubular vortex oil separator and the platform production water treatment reinjection system. This invention utilizes the weak swirling flow and weight deposition formed by the tangential inlet to complete degassing, and the secondary swirling flow formed by the flow stabilizer and the flow regulating components, combined with the inclined plate combination, to complete sand removal, ensuring that the subsequent tubular vortex pre-water separation and tubular oil separator operate in the optimal working environment.

[0026] The following section uses a degassing and sand removal device as an example to explain the entire technical process in detail.

[0027] Example 1 like Figures 1 to 4As shown, a key piece of equipment for expanding an aging offshore high-water-cut oilfield platform includes the platform's original primary three-phase separator 1, the platform's original secondary three-phase separator 2, a degassing and desanding device 3, the platform's natural gas treatment and recovery system 4, the platform's oil-containing solids recovery system 5, a tubular vortex pre-dehydrator 6, a tubular vortex oil separator 7, the platform's production water treatment and reinjection system 8, an exhaust pipe 9, and valve assemblies. The platform's original primary three-phase separator 1 and the platform's original secondary three-phase separator 2 are connected. The platform's original primary three-phase separator 1 is connected to the platform's produced fluid supply pipe. The tangential inlet pipe 12 of the degassing and desanding device 3 is used for the platform's produced fluid to enter. The exhaust pipe 9 of the degassing and desanding device 3 is connected to the platform's natural gas treatment and recovery system 4. The sand discharge pipe 17 of the degassing and desanding device 3 is connected to the platform's oil-containing solids recovery system 5. The outlet pipe 14 of the degassing and desanding device 3 is connected to the tubular vortex pre-dehydrator 6. The tubular vortex pre-dehydrator 6, tubular vortex oil separator 7, and platform production water treatment reinjection system 8 are connected in sequence. The platform's original primary three-phase separator 1 and platform's original secondary three-phase separator 2 are respectively connected to the tubular vortex oil separator 7. The tubular vortex pre-dehydrator 6 and tubular vortex oil separator 7 are respectively connected to the platform's original secondary three-phase separator 2. Valve assemblies are respectively provided between the platform's produced fluid inlet pipe and the platform's original primary three-phase separator 1, between the degassing and desanding device 3 and the platform's produced fluid inlet pipe, between the degassing and desanding device 3 and the tubular vortex pre-dehydrator 6, between the tubular vortex pre-dehydrator 6 and the tubular vortex oil separator 7, between the tubular vortex pre-dehydrator 6 and the platform's original secondary three-phase separator 2, between the tubular vortex oil separator 7 and the platform's original secondary three-phase separator 2, and between the tubular vortex oil separator 7 and the platform production water treatment reinjection system 8.

[0028] The valve assembly includes a first valve 19-1, a second valve 19-2, a third valve 19-3, a fourth valve 19-4, a fifth valve 19-5, a sixth valve 19-6, and a seventh valve 19-7. The first valve 19-1 is located between the degassing and desanding device 3 and the platform's produced liquid inlet pipe. The second valve 19-2 is located between the platform's produced liquid inlet pipe and the platform's original primary three-phase separator 1. The third valve 19-3 is located between the degassing and desanding device 3 and the tubular vortex pre-dehydrator 6. The fourth valve 19-4 is located between the tubular vortex pre-dehydrator 6 and the platform's original secondary three-phase separator 2. The fifth valve 19-5 is located between the tubular vortex pre-dehydrator 6 and the tubular vortex oil separator 7. The sixth valve 19-6 is located between the tubular vortex oil separator 7 and the platform's original secondary three-phase separator 2. The seventh valve 19-7 is located between the tubular vortex oil separator 7 and the platform's production water treatment reinjection system 8.

[0029] like Figures 2 to 4As shown, the degassing and sand removal device 3 also includes a wire mesh demister 10, a separation tank body 11, a tangential liquid inlet pipe 12, a flow stabilizing cylinder degassing component 13, a liquid outlet pipe 14, and a sand removal device. The separation tank body 11 has a vertical tank-like structure. The tangential liquid inlet pipe 12 is provided on the upper side wall of the separation tank body 11. The wire mesh demister 10, the flow stabilizing cylinder degassing component 13, and the sand removal device are distributed sequentially from top to bottom inside the separation tank body 11. The separation tank body 11 and the flow stabilizing cylinder degassing component 13 form a circulating space so that the platform's produced liquid enters the circulating space through the tangential liquid inlet pipe 12 to form a swirling flow. The exhaust pipe 9 is located at the top of the separation tank body 11.

[0030] like Figure 4 As shown, the flow stabilizer degassing component 13 includes a flow stabilizer body and a flow stabilizer support 18-1 and a flow regulating component 8-2 disposed at the bottom of the tank. The flow stabilizer support 18-1 fixes the flow stabilizer degassing component 13 to the separation tank body 11, and at the same time realizes that the liquid flows downward along the separation tank body 11. After the flow regulating component 18-2 enhances the swirling flow, the less dense gas phase converges towards the center of the flow stabilizer body, and the more dense solid is transported outward to the inner wall of the separation tank body 11 and enters the sand removal device. The liquid is located between the solid phase and the gas phase and is discharged from the liquid outlet pipe 14.

[0031] Among them, the flow stabilizer support 18-1 is arc-shaped, with an arc plate thickness of 16mm, the arc is the same as the inner cylinder diameter, and the width and height are both 50mm; the flow regulating component 18-2 is an inclined stiffener, with a stiffener thickness of 10mm, a width and height of 50mm, and an angle of 70° with the axis, and the inclination direction is consistent with the tangential inlet direction.

[0032] like Figure 3 As shown, the sand removal device includes a sand settling inclined plate component 15, a conical end cap 16, and a sand discharge pipe 17 arranged sequentially from top to bottom. The sand settling inclined plate component 15 is a hollow cone with a wall thickness of 5mm and a cone angle of 45°. The small end of the sand settling inclined plate component 15 opens upwards, and a sand flushing pipe is installed inside the small end opening of the sand settling inclined plate component 15. When the sand deposited at the bottom cannot be discharged, high-pressure water is added through the sand flushing pipe to flush out the deposited sand. The large end of the sand settling inclined plate component 15 is fixed to the upper part of the conical end cap 16. The bottom of the conical head 16 is connected to the sand discharge pipe 17, which is located at the bottom of the separation tank body 11. This allows a portion of the denser solids to settle down along the inner wall of the separation tank body 11 into the conical head 16 and then be discharged from the sand discharge pipe 17. Another portion of the fine sand that does not sink to the bottom of the conical head 16 flows upward with the liquid, encounters the inclined plate component 15, aggregates on the inclined plate, slides down the inclined plate, sinks back into the conical head 16, and is discharged from the sand discharge pipe 17.

[0033] Work process: The produced fluid enters the degassing and desanding unit 3, where it undergoes rapid degassing and desanding within a 1-minute hydraulic residence time. The extracted natural gas enters the platform's natural gas treatment and recovery system 4. The oily sand from the separator is discharged into the platform's oily solids recovery system 5. The treated produced fluid enters the tubular vortex pre-dehydrator 6, where 80% of the water is separated within a 1.8-second hydraulic residence time after strong vortex flow. The dehydrated crude oil then enters the platform's existing secondary three-phase separator 2. The separated water, along with the water from the platform's existing primary three-phase separator 1 and secondary three-phase separator 2, enters the tubular vortex oil separator 7. After another 1.8-second hydraulic residence time, the oil in the production water is rapidly removed, meeting the platform's production water treatment system requirements. The treated water phase is then discharged into the platform's existing production water treatment and reinjection system 8.

[0034] The working process of the degassing and sand removal device 3 is as follows: the tangential inlet pipe 12 is used for the platform produced liquid to enter. The produced liquid enters the circulation space between the main body of the separator tank 11 and the degassing component 13 of the flow stabilizer through the tangential inlet pipe 12 and forms a swirling flow. Under the action of swirling flow, the less dense gas phase gathers in the middle of the stabilizing cylinder degassing component 13 and floats up. The floated gas phase is further purified by the wire mesh demister 10 and discharged into the platform natural gas treatment and recovery system 4 through the exhaust pipe 9. The liquid flows down along the main body 11 of the separator. The swirling flow is enhanced by the support of the stabilizing cylinder and the flow regulating component 18, so that the less dense gas phase gathers towards the center of the stabilizing cylinder degassing component 13. The denser solids move outward to the inner wall of the main body 11 of the separator. The liquid is located between the solid and gas and is discharged from the liquid outlet pipe 14. The densest solids are deposited down along the inner wall of the main body 11 of the separator and are discharged from the sand discharge pipe 17 after a certain amount is deposited in the conical head 16. Some fine sand that does not sink to the bottom of the conical head 16 flows upward with the liquid and encounters the inclined plate of the sand settling plate component 15. It then gathers on the inclined plate and slides down the inclined plate and sinks into the conical head 16 again, thus achieving efficient sand removal.

[0035] Example 2 A process for improving the efficiency and capacity of produced fluids on offshore platforms, including the device for improving the efficiency and capacity of produced fluids on offshore platforms as described in Example 1, specifically includes the following steps: S1: The produced fluid from the platform enters through the inlet of the degassing and desanding device 3 to complete the degassing and desanding of the produced fluid.

[0036] The specific operation process of step S1 is as follows: First valve 19-1 and second valve 19-2 are opened simultaneously. The inlet of the degassing and desanding device 3 is connected to the platform's produced liquid inlet channel through first valve 19-1. Based on the increased liquid volume on the platform, the opening of first valve 19-1 is adjusted to discharge all the increased liquid volume into the degassing and desanding device 3 for processing. The remaining produced liquid enters the platform's original primary three-phase separator 1 through second valve 19-2 for processing. After liquid extraction, the processing capacity of the platform's original primary three-phase separator 1 meets the original design capacity.

[0037] S2: The extracted natural gas enters the platform's natural gas treatment and recovery system 4, while the oily sand from the separator is discharged into the platform's oily solids recovery system 5. The third valve 19-3 is used to regulate the liquid level in the degassing and desanding unit 3. The produced liquid discharged from the degassing and desanding unit 3 enters the tubular vortex pre-dehydrator 6 after passing through valve 19-3, where 80% of the water is separated within a 1.8s hydraulic residence time due to strong vortex flow. The fourth valve 19-4 and the fifth valve 19-5 are used to regulate the discharge volume of production wastewater from the tubular vortex pre-dehydrator 6. The discharge volume is 80% of the water content in the produced liquid. The remaining 20% ​​of the water and the oil phase in the produced liquid are discharged into the platform's existing two-stage three-phase separator 2 after passing through the fourth valve 19-4.

[0038] S3: The water extracted by the tubular vortex pre-dehydrator 6, as well as the water from the platform's original primary three-phase separator 1 and the existing secondary three-phase separator 2, all enter the tubular vortex oil separator 7. After passing through a strong vortex, the production water undergoes rapid oil removal within a hydraulic residence time of 1.8 seconds, meeting the platform's production water treatment system requirements. The sixth valve 19-6 and the seventh valve 19-7 are used to regulate the water output of the tubular vortex oil separator 7, which is 95% of the inlet flow rate of the tubular vortex oil separator 7. The treated water phase is then discharged into the platform's production water treatment reinjection system 8.

[0039] S4: The 5% oily wastewater recovered by the tubular vortex oil separator 7 is mixed with the oil phase of the tubular vortex pre-dehydrator 6 through the sixth valve 19-6 and discharged into the existing secondary three-phase separator 2 on the platform.

[0040] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A key equipment for expanding the capacity of an old platform for offshore high water-cut oilfields, characterized in that, The platform original first-stage three-phase separator (1), the platform original second-stage three-phase separator (2), the degassing and desanding device (3), the platform natural gas treatment and recovery system (4), the platform oil-containing solid recovery system (5), the tubular vortex pre-dehydrator (6), the tubular vortex oil removal device (7), the platform produced water treatment and reinjection system (8), the exhaust pipe (9) and the valve assembly are sequentially connected.

2. The key equipment for expanding the capacity of an old offshore high water-cut oilfield platform according to claim 1, characterized in that, The degassing and desanding device (3) further comprises a wire mesh demister (10), a separation tank body (11), a steady flow cylinder degassing component (13), a liquid outlet pipe (14) and a sand removal device, the separation tank body (11) is a vertical tank structure, a tangential liquid inlet pipe (12) is arranged on the upper side wall of the separation tank body (11), the wire mesh demister (10), the steady flow cylinder degassing component (13) and the sand removal device are sequentially arranged in the separation tank body (11) from top to bottom, the separation tank body (11) and the steady flow cylinder degassing component (13) form a circulating space, so that the platform produced liquid enters the circulating space through the tangential liquid inlet pipe (12) to form a cyclone, and the exhaust pipe (9) is arranged on the top of the separation tank body (11).

3. The key equipment for revamping the aging offshore high water-cut oilfield platform according to claim 2, characterized in that, The flow stabilizing cylinder degassing component (13) comprises a flow stabilizing cylinder body, a flow stabilizing cylinder support (18-1) arranged at the bottom of the barrel body, and a flow adjusting member (18-2), the flow stabilizing cylinder support (18-1) fixes the flow stabilizing cylinder degassing component (13) on the separation tank body (11), and at the same time, realizes downward flow of liquid along the separation tank body (11), strengthens the cyclone through the flow adjusting member (18-2), makes the gas phase with small density converge to the center of the flow stabilizing cylinder body, makes the solid phase with large density move outward to the inner wall of the separation tank body (11) and enter the sand removing device, and the liquid is between the solid phase and the gas phase and is discharged from the liquid outlet pipe (14).

4. The key equipment for revamping the aging offshore high water-cut oilfield platform according to claim 3, characterized in that, The sand removing device comprises a sand setting inclined plate component (15), a conical head (16), and the sand discharge pipe (17) arranged in sequence from top to bottom, the sand setting inclined plate component (15) is arranged above the conical head (16), the bottom of the conical head (16) is connected with the sand discharge pipe (17), and the sand discharge pipe (17) is arranged at the bottom of the separation tank body (11), so that part of the solid phase with large density deposits in the conical head (16) and is discharged from the sand discharge pipe (17), and the other part of the fine sand which does not sink into the bottom of the conical head (16) converges on the inclined plate and slides down the inclined plate again to sink into the conical head (16) and is discharged from the sand discharge pipe (17) when flowing upward with the liquid.

5. The key equipment for revamping the aging offshore high water-cut oilfield platform according to claim 4, characterized in that, The degassing and sand removing device (3) comprises a wire mesh mist eliminator (10), a separation tank body (11), a tangential liquid inlet pipe (12), a flow stabilizing cylinder degassing component (13), a liquid outlet pipe (14), and a sand removing device, the separation tank body (11) is a vertical tank structure, the tangential liquid inlet pipe (12) is arranged above the side wall of the separation tank body (11), the wire mesh mist eliminator (10), the flow stabilizing cylinder degassing component (13), and the sand removing device are arranged in sequence from top to bottom in the separation tank body (11), the separation tank body (11) and the flow stabilizing cylinder degassing component (13) form a circulating space, so that the platform produced liquid enters the circulating space through the tangential liquid inlet pipe (12) to form a cyclone, and the exhaust pipe (9) is arranged at the top of the separation tank body (11).

6. The offshore high water cut oilfield mature platform expansion key equipment according to claim 5, characterized in that, The flow stabilizing cylinder degassing component (13) comprises a flow stabilizing cylinder body, a flow stabilizing cylinder support (18-1) arranged at the bottom of the barrel body, and a flow adjusting member (18-2), the flow stabilizing cylinder support (18-1) fixes the flow stabilizing cylinder degassing component (13) on the separation tank body (11), and at the same time, realizes downward flow of liquid along the separation tank body (11), strengthens the cyclone through the flow adjusting member (18-2), makes the gas phase with small density converge to the center of the flow stabilizing cylinder body, makes the solid phase with large density move outward to the inner wall of the separation tank body (11) and enter the sand removing device, and the liquid is between the solid phase and the gas phase and is discharged from the liquid outlet pipe (14).

7. The offshore high water cut oilfield mature platform expansion key equipment according to claim 6, characterized in that, The sand removing device comprises a sand setting inclined plate part (15), a conical head (16) and the sand discharging pipe (17) arranged in sequence from top to bottom, the sand setting inclined plate part (15) is hollow conical, the small end of the sand setting inclined plate part (15) is upwardly open, the large end of the sand setting inclined plate part (15) is fixed above the conical head (16), the bottom of the conical head (16) is connected with the sand discharging pipe (17), and the sand discharging pipe (17) is arranged at the bottom of the separation tank body (11), so that part of solid with large density is deposited in the conical head (16) along the inner wall of the separation tank body (11) and then discharged from the sand discharging pipe (17), and the other part of fine sand which does not sink into the bottom of the conical head (16) is gathered on the inclined plate and then sinks into the conical head (16) again when flowing upward along with liquid and colliding with the inclined plate of the sand setting inclined plate part (15), and then discharged from the sand discharging pipe (17).

8. A process for expanding the capacity of an aging offshore high water cut oil field platform, characterized by, The offshore high water-cut oilfield old platform expansion key equipment comprises the following steps: Platform produced liquid enters from the inlet of the degassing sand remover (3), and degassing sand removal of the produced liquid is completed; Natural gas removed by the degassing sand remover (3) enters a platform natural gas treatment and recovery system (4), oil-containing sand separated by the degassing sand remover (3) is discharged into a platform oil-containing solid recovery system (5), and produced liquid treated by the degassing sand remover (3) enters a tubular vortex pre-dehydrator (6), a part of water is separated by strong cyclone, and the remaining water and dehydrated crude oil enter a platform original secondary three-phase separator (2); Water removed by the tubular vortex pre-dehydrator (6), water from a platform original primary three-phase separator (1) and a platform original secondary three-phase separator (2) are uniformly discharged into a tubular vortex oil remover (7), rapid oil removal of production water is completed by strong cyclone, and the platform production water treatment system index requirement is reached, and the water phase after treatment is discharged into a platform existing production water treatment and reinjection system (8); Oil-containing sewage recovered by the tubular vortex oil remover (7) is mixed with the oil phase of the tubular vortex pre-dehydrator (6), and is discharged into the platform existing secondary three-phase separator (2) together.

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