A ground-based liquid preparation device for profile control on a small offshore platform

Abstract

This invention discloses a surface-based fluid preparation device for profile control on small offshore platforms, comprising a storage and distribution system, a forced stretching system, a powerful dispersion system, a crosslinking agent mixing system, a conveying system, and an automatic control system. By integrating the online preparation process without a curing tank with the crosslinking mixing system, and through an integrated design of the preparation room and automatic control room, it eliminates the need for large-capacity curing tanks, separate crosslinking agent mixing skids, and separate automatic control rooms found in traditional devices, significantly reducing the device's footprint and operating weight. Through structural optimization of the forced stretching system and powerful dispersion system, the polymer concentration can be prepared up to 10,000 ppm, with a total processing capacity of up to 80 cubic meters per hour. Combined with multiple independently controlled crosslinking agent pumps, it can meet the needs of simultaneous profile control operations across multiple wells. This device can also be equipped with a nitrogen sealing system to reduce oxidative degradation of the profile control system and an automatic cleaning system for self-cleaning filters, making it particularly suitable for profile control operations on small offshore platforms.

Description

Technical Field

[0001] This invention belongs to the field of petroleum engineering technology, and more specifically, it relates to a ground-based fluid preparation device suitable for profile control operations on small offshore platforms. Background Technology

[0002] After years of intensive development, my country's old offshore oilfields have generally entered the late stage of high water-cut development. Water injection is one of the most widely used development methods in offshore oilfields to maintain formation pressure and improve oil recovery. However, long-term intensive water injection has exacerbated reservoir heterogeneity, leading to the widespread development of high-permeability layers and large pores. Injected water circulates ineffectively along these high-permeability channels, resulting in low injection efficiency, reduced water drive sweep volume, and severely impacting oilfield development. It also significantly increases the burden of treating produced fluids on the surface, leading to a substantial increase in the operating costs of water treatment equipment. Therefore, large-scale water injection well profile control operations are urgently needed to improve injection efficiency, enhance oilfield recovery, and reduce the burden of treating produced fluids on the surface.

[0003] The operating environment of offshore oilfields differs significantly from that of onshore oilfields. Offshore platforms have limited space and load-bearing capacity. Furthermore, frequent well workovers in older oilfields severely restrict the transportation, hoisting, installation, and maintenance of large equipment, resulting in very limited space and time windows for surface injection equipment used in profile control operations. Currently, the surface injection devices used for profile control operations in onshore oilfields and some large offshore platforms generally employ traditional curing tank technology. These devices typically include a mixing room, an automatic control room, a crosslinking agent mixing system, and multiple large-capacity curing tanks. The entire system occupies a large area, has a high operating weight, and requires a long polymer dissolution time, which cannot meet the space and load-bearing limitations of small offshore platforms. It can only support 1-2 wells simultaneously for profile control operations, with each operation lasting 2-3 months. If more wells need to be simultaneously subjected to profile control operations, they must be carried out sequentially, leading to a longer overall operation cycle (extending to six months). This affects the normal daily production and operation of offshore platforms, thus hindering the widespread application of profile control and displacement control technologies on some small offshore platforms.

[0004] At present, the main technical challenges faced by offshore oilfield profile control operations include: (1) For traditional curing tank processes: First, traditional injection equipment occupies a large area and is difficult to adapt to the limited space conditions of small offshore platforms; second, existing equipment has a high operating weight and imposes stringent requirements on the platform's load-bearing capacity; third, polymer dissolution time is long and cannot meet the needs of efficient operation; (2) For new curing tank-less liquid preparation processes (existing invention patent CN115888519A): The polymer preparation concentration is low (maximum 8000ppm) and the liquid preparation volume is small (maximum 25 cubic meters / hour), which cannot meet the process requirements of simultaneous profile control operations of multiple wells, affecting the efficiency of operation implementation. Moreover, the new curing tank-less process can only prepare polymer solutions and still requires additional crosslinking agent equipment to prepare the profile control system. Therefore, there is still a problem of large area occupied due to multiple equipment operating together; (3) Whether it is the traditional curing tank process or the new curing tank-less process, an additional automatic control room needs to be set up separately, further increasing the area occupied and increasing transportation and hoisting costs. These problems severely restrict the promotion and application of profile control and displacement control technologies on small offshore platforms. There is an urgent need to develop a new type of surface fluid distribution device suitable for profile control operations on small offshore platforms in order to solve the above-mentioned technical problems and meet the needs of small offshore platforms to carry out profile control operations simultaneously in multiple wells. Summary of the Invention

[0005] This invention aims to solve at least one of the technical problems existing in the prior art. To this end, this invention provides a surface fluid preparation device for profile control on small offshore platforms, aiming to solve the problem of surface injection when small offshore platforms have limited remaining usable space and need to carry out multiple well-driven profile control operations simultaneously.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: a ground-based liquid preparation device for profile control on a small offshore platform, comprising a polymer storage and discharging system, a polymer forced stretching system, a polymer strong dispersion system, a crosslinking agent mixing system, and a polymer solution conveying system, wherein: the polymer storage and discharging system includes a hopper, the hopper is equipped with a weight sensor, and the outlet of the hopper is sequentially connected to a screw feeder and a venturi tube; the polymer forced stretching system adopts a two-stage forced stretching toothed disc structure, the first-stage forced stretching toothed disc includes a first-stage rotor and a first-stage stator, the rotor teeth of the first-stage rotor adopt a boomerang-shaped coarse tooth structure, and the stator teeth of the first-stage stator adopt a dense tooth structure; the second-stage forced stretching toothed disc includes a second-stage rotor and a second-stage stator, the second-stage rotor includes an outer ring rotor teeth and an inner ring rotor teeth, the outer ring rotor teeth adopt a polygonal coarse tooth structure, and the inner ring rotor teeth adopt a... The structure features a wedge-shaped coarse tooth structure. The second-order stator includes coaxially arranged outer and inner stator teeth, which respectively contact the outer and inner rotor teeth. Both the first-order and second-order rotors are internally equipped with liquid guide wheels. The polymer high-strength dispersion system includes a dispersion chamber, a dispersion bed, and a top-mounted drive motor. The dispersion bed consists of an inner grid tube, an outer grid tube, a bottom plate, and a dispersion bed mesh filled inside. A mandrel is installed inside the dispersion bed, vertically extending out of the dispersion chamber and connected to the top-mounted drive motor. The crosslinking agent mixing system includes multiple independently controlled crosslinking agent pumps. The outlet of the polymer high-strength dispersion system is connected to the inlet of the crosslinking agent pumps. Through these multiple pumps, the crosslinking agent is mixed with the prepared polymer solution in the required proportion, and then transported to the wellhead via the polymer solution delivery system.

[0007] Preferably, the first-order rotor has 6-20 teeth arranged radially in a circular pattern, and the first-order stator has 300-400 teeth in a dense tooth structure. The outer ring rotor teeth, inner ring rotor teeth, outer ring stator teeth, and inner ring stator teeth are all designed with 20-40 teeth. The outer ring rotor teeth are arranged circumferentially along the outer edge of the second-order rotor, and the inner ring rotor teeth are arranged radially inside the outer ring rotor teeth.

[0008] As a preferred option, it also includes an automatic control system set up in the automation control room. The automatic control system is based on a PLC, which collects flow meter, pressure and liquid level signals in real time, and automatically adjusts the rotation speed of the polymer feeding system, the stretching speed of the polymer forced stretching system, the dispersion speed of the polymer strong dispersion system, and the conveying frequency of the crosslinking agent pump and the screw feeder to achieve closed-loop precise control of the entire process. Meanwhile, the polymer storage and feeding system, polymer forced stretching system, polymer strong dispersion system, crosslinking agent mixing system and polymer solution delivery system are integrated in the liquid preparation room. The automated control room and the liquid preparation room adopt an integrated partition design. The liquid preparation room is designed according to the ordinary explosion-proof standard for marine applications, while the automated control room is designed according to the positive pressure explosion-proof standard for marine applications. The two operate independently and do not interfere with each other.

[0009] Preferably, the hopper consists of two independent hoppers connected in parallel, and the polymer forced stretching system is configured in two sets in parallel, with a total processing capacity of not less than 80 cubic meters per hour.

[0010] Preferably, the thickness of the dispersion bed wire mesh is designed to be 15-25cm, and the rotation speed of the high-power dispersion module is designed to be 500-1000rpm.

[0011] Preferably, the dispersion chamber of the polymer high-strength dispersion system is equipped with an electric heating rod for thermal degradation treatment when the polymer becomes clogged.

[0012] Preferably, the multiple crosslinking agent pumps of the crosslinking agent mixing system are independently controlled one-to-one, which can simultaneously prepare profile control systems of different concentrations for multiple injection wells.

[0013] Preferably, a nitrogen sealing system is also included, comprising a nitrogen inlet and a micro-pressure control valve assembly located at the top of the polymer forced stretching system and the polymer strong dispersion system, and an annular nitrogen air curtain assembly located inside the feed port of the hopper, maintaining the oxygen content in the system below 0.1% throughout the liquid preparation process.

[0014] Preferably, the nitrogen sealing system is a skid-mounted structure that can be configured according to the platform space conditions.

[0015] Preferably, the system also includes an inlet filter and an outlet filter. The outlet of the inlet filter is connected to the inlet of the venturi tube to filter out impurities in the process feed water. The inlet of the outlet filter is connected to the outlet of the polymer solution delivery system to filter out impurities in the polymer solution. Simultaneously, the inlet and outlet filters have a self-cleaning function. When the pressure difference between the inlet and outlet of the inlet or outlet filter reaches 0.15 MPa, a backwashing procedure is automatically initiated. The backwash water source is taken from the platform's freshwater system or pretreated seawater, and the backwash wastewater is automatically discharged into the platform's open discharge tank or wastewater collection system.

[0016] The present invention has the following advantages due to the adoption of the above technical solutions: 1. Significantly reduce the plant's footprint and operating weight: Through two integrated designs, namely the integration of the online preparation process without curing tanks and the crosslinking mixing system, as well as the integration of the preparation room and the automatic control room, multiple large-capacity curing tanks, crosslinking agent mixing skids, and automatic control rooms, etc., which are found in traditional plants, the plant's footprint and operating weight are significantly reduced, meeting the space and load-bearing limitations of small offshore platforms.

[0017] 2. Improved solution preparation capacity and efficiency: By optimizing and upgrading the structure of the forced stretching and strong dispersion system, the solution preparation capacity of the polymer preparation system has been greatly improved. The concentration has been increased from 8,000 to 10,000 ppm, and the throughput has been increased from 25 cubic meters / hour to 80 cubic meters / hour, realizing the rapid online preparation of polymer solutions with higher discharge capacity and concentration.

[0018] 3. Enable simultaneous multi-well profile control operations: Through the one-to-one independent control design of multiple crosslinking agent pumps in the crosslinking agent mixing system, personalized concentration formulations of profile control systems for different injection wells can be achieved, meeting the needs of simultaneous multi-well profile control operations.

[0019] 4. Improve the safety and adaptability of the equipment: The automated control room is designed according to the marine positive pressure explosion-proof standard, and the liquid preparation room is designed according to the marine general explosion-proof standard. The two are integrated into one unit but do not interfere with each other and can operate independently, which improves the safety and adaptability of the equipment in the special marine environment.

[0020] 5. Achieve efficient preparation of profile control system: By adopting online preparation process without curing tank and integrated liquid preparation-control process, the liquid preparation capacity is improved while the equipment footprint and operating weight are significantly reduced, achieving efficient preparation of profile control system and providing process support for multi-well profile control on small offshore platforms.

[0021] 6. The entire process uses a nitrogen-sealed system to achieve full nitrogen coverage, isolate oxygen, and avoid viscosity loss caused by oxidative degradation during the preparation of the profile control system.

[0022] 7. The solution outlet filter has an automatic self-cleaning function, which can automatically clean and regenerate the filter screen online. This not only significantly reduces the operation cost and pollution risk of manual disassembly and cleaning, but also maintains a stable filtration flux, effectively avoiding fluctuations in solution quality caused by filter screen blockage, thereby improving the level of intelligence in the solution preparation process. Attached Figure Description

[0023] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Throughout the drawings, the same reference numerals denote the same parts. In the drawings: Figure 1 This is a schematic diagram of the overall structure of a ground-based liquid preparation device for profile control of a small offshore platform provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of the structure of the first-stage toothed disk in a polymer forced stretching system provided in an embodiment of the present invention; Figure 3 This is a schematic diagram of the structure of the second-stage toothed disk in a polymer forced stretching system provided in an embodiment of the present invention; Figure 4 This is a schematic diagram of the structure of a high-polymer dispersion system provided in an embodiment of the present invention; Figure 5 This is a schematic diagram of the structure of a powerful dispersion module provided in an embodiment of the present invention. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of the present invention clearer, specific embodiments of the present invention will be further described below with reference to the accompanying drawings. Although exemplary embodiments of the present invention are shown in the drawings, it should be understood that the present invention can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided to enable a more thorough understanding of the present invention and to fully convey the scope of the present invention to those skilled in the art.

[0025] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0026] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0027] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; 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; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0028] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0029] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0030] The ground-based fluid preparation device for profile control on small offshore platforms provided by this invention includes a storage and distribution system, a forced stretching system, a powerful dispersion system, a crosslinking agent mixing system, a conveying system, and an automatic control system. Through the integration of a tankless online preparation process with the crosslinking mixing system, and an integrated design of the preparation room and automatic control room, it eliminates the need for large-capacity ripening tanks, separate crosslinking agent mixing skids, and separate automatic control rooms found in traditional devices, significantly reducing the device's footprint and operating weight. Through structural optimization of the forced stretching and powerful dispersion systems, the polymer concentration can be prepared up to 10,000 ppm, with a total processing capacity of up to 80 cubic meters per hour. Combined with multiple independently controlled crosslinking agent pumps, it can meet the needs of simultaneous profile control operations across multiple wells. This device can also be equipped with a nitrogen sealing system to reduce oxidative degradation of the profile control system and an automatic cleaning system for self-cleaning filters, making it particularly suitable for profile control operations on small offshore platforms.

[0031] The following is a detailed description of the ground-based liquid preparation device for profile control of small offshore platforms provided in the embodiments of the present invention, with reference to the accompanying drawings.

[0032] Please see Figure 1 The present invention provides a ground-based liquid preparation device for profile control of small offshore platforms, comprising a polymer storage and feeding system 1, a polymer forced stretching system 2, a polymer strong dispersion system 3, a crosslinking agent mixing system 4, a polymer solution delivery system 5, and an automatic control system 6.

[0033] The polymer storage and feeding system 1 mainly consists of a hopper 11, a screw feeder 12, and a venturi tube 13. In this embodiment, two independent hoppers 11 are arranged in parallel, each equipped with a weight sensor (not shown in the figure). The hopper 11 conveys powder to the venturi tube 13 via the screw feeder 12 to mix with water, and then conveys it to the subsequent polymer forced stretching system 2. The weight sensor monitors the weight of the polymer in the hopper 11 in real time and transmits the data to the automatic control system 5 to ensure that the metering accuracy is controlled within 0.5%.

[0034] The polymer forced stretching system 2 is an optimized modification of the forced stretching toothed disc structure based on the forced stretching system in Chinese invention patent application CN115888519A. Existing forced stretching systems employ a multi-stage (2-4 stage) toothed disc structure. In practical applications, due to the high viscosity of the polymer, the multi-stage toothed disc design exhibits a significant throttling effect, resulting in a maximum processing capacity of 25 cubic meters per hour, making further increases in processing capacity quite difficult. Please refer to [link / reference]. Figure 2 , Figure 3This invention employs a two-stage forced-tension gear disc design. The first-stage forced-tension gear disc includes a first-stage rotor 21 and a first-stage stator 22. The rotor teeth of the first-stage rotor 21 adopt a boomerang-shaped coarse tooth structure design, with 6-20 teeth arranged radially in a circular pattern. The stator teeth of the first-stage stator 22 adopt a dense tooth structure design, increasing the number of teeth from the existing 20-40 coarse tooth structure to a 300-400 fine tooth structure, achieving finer and denser tooth gaps. Furthermore, the boomerang-shaped coarse tooth structure increases the grinding contact surface between the stator and rotor, improving the grinding effect. The second-stage forced-tension gear disc includes... The second-order rotor 23 and second-order stator 24 are used. The second-order rotor 23 includes outer and inner rotor teeth. The outer rotor teeth have a polygonal coarse tooth structure and are arranged circumferentially along the outer edge of the second-order rotor 23. The inner rotor teeth have a wedge-shaped coarse tooth structure and are arranged radially inside the outer rotor teeth. The second-order stator 24 includes coaxially arranged outer and inner stator teeth, which are in contact with the outer and inner rotor teeth, respectively. The number of teeth in each of the outer and inner rotor teeth, as well as the outer and inner stator teeth, is designed to be 20-40. Simultaneously, both the first-order rotor 21 and the second-order rotor 23 are additionally equipped with liquid guide wheels 25 to achieve internal pressurization, reduce the throttling effect, and increase the processing capacity, with a maximum liquid dispensing capacity of 40 cubic meters per hour. Furthermore, this invention employs a dual forced stretching system 2 in parallel, increasing the total processing capacity from 40 cubic meters per hour to 80 cubic meters per hour.

[0035] Please see Figure 4 , Figure 5 The polymer high-strength dispersion system 3 includes a dispersion chamber 31, a high-strength dispersion module 32, and a top-mounted drive motor 33. The high-strength dispersion module 32 includes a dispersion bed composed of an inner grid tube 321, an outer grid tube 322, and a bottom plate 323, and a mandrel 324 disposed within the dispersion bed. A dispersion bed mesh (not shown in the figure) is placed inside the dispersion bed as packing. The dispersion bed is located within the dispersion chamber 31, and the mandrel 324 vertically extends out of the dispersion chamber 31 and is connected to the top-mounted drive motor 33 located at the top of the dispersion chamber 31. The thickness of the dispersion bed mesh is designed to be 15-25 cm, and the rotation speed of the high-strength dispersion module 32 is designed to be 500-1000 rpm. Under these conditions, the viscosity retention rate reaches 95%, the dispersion and dissolution degree reaches 100%, and the shortest transit time is 8.4 s. Furthermore, an electric heating rod (not shown in the figure) can be installed inside the dispersion chamber 31. If polymer blockage or other problems occur, it can be heated for thermal degradation, solving the problem of polymer blockage in the packing bed. In addition, the invention adopts a top-mounted drive motor design, which greatly reduces mechanical vibration caused by rotation and ensures stable operation of the equipment.

[0036] Therefore, through the joint upgrade and modification of the polymer forced stretching system 2 and the polymer strong dispersion system 3, rapid online preparation of polymer solutions without a curing tank was achieved. Compared with the traditional curing tank process, this online preparation process significantly shortens the polymer dissolution time, reduces the equipment footprint and operating weight, and is particularly suitable for the space constraints of small offshore platforms. At the same time, it greatly improves the solution preparation capacity of the polymer preparation system, increasing the concentration from 8000ppm to 10000ppm and the processing capacity from 25 cubic meters / hour to 80 cubic meters / hour, meeting the needs of efficient operations in offshore oil fields.

[0037] The crosslinking agent mixing system 4, polymer storage and feeding system 2, polymer forced stretching system 2, polymer strong dispersion system 3, and polymer solution delivery system 5 are integrated into the liquid preparation room. The outlet of the polymer strong dispersion system 3 is connected to the inlet of the crosslinking agent mixing system. The crosslinking agent mixing system 4 consists of multiple crosslinking agent pumps (only one pump is shown in the figure). Through these multiple pumps, the crosslinking agent is mixed with the prepared polymer solution in the required proportion, and then delivered to the wellhead via the polymer solution delivery system 5. This avoids the need for an additional crosslinking agent mixing skid, thereby reducing the floor space required.

[0038] In the above embodiments, preferably, the automatic control system 6 is located in the automation control room, with a PLC as its core. It collects flow meter, pressure, and liquid level signals in real time and automatically adjusts the rotation speed of the polymer feeding system 1, the stretching speed of the polymer forced stretching system 2, the dispersion speed of the polymer strong dispersion system 3, and the conveying frequency of the crosslinking agent pump and the screw feeder 12, achieving closed-loop precise control of the entire process. Furthermore, the automation control room and the liquid preparation room are integrated into one unit, with a single, isolated design. They operate independently without interference. The liquid preparation room is designed according to ordinary marine explosion-proof standards, while the automation control room is designed according to marine positive pressure explosion-proof standards.

[0039] In the above embodiments, preferably, a nitrogen sealing system 7 is also included. This nitrogen sealing system 7 includes: a nitrogen inlet and a micro-pressure control valve assembly located at the top of the polymer forced stretching system 2 and the polymer strong dispersion system 3; and an annular nitrogen air curtain assembly located inside the feeding port of the hopper 11. Through the nitrogen sealing system 7, during the entire liquid preparation process (feeding, mixing, liquid preparation, sampling, and liquid transfer), the nitrogen sealing system 7 maintains a slight positive pressure of nitrogen. High-purity nitrogen is continuously introduced into each interface to form a gas seal barrier. Combined with an oxygen concentration sensor and automatic nitrogen replenishment logic, the oxygen content inside the tank and pipelines is consistently controlled below 0.1%, achieving full-process oxygen isolation, reducing the oxidative degradation of the profile control system, and improving the viscosity retention rate of the prepared liquid. Furthermore, the nitrogen sealing system 7 is a separate skid, which can be used depending on the platform space. If there is ample space, the nitrogen sealing system 7 can be used; if space is limited, it can be omitted.

[0040] In the above embodiments, preferably, an inlet filter 8 and an outlet filter 9 are also included. The outlet of the inlet filter 8 is connected to the inlet of the venturi tube 13 to filter out impurities in the process feed water. The inlet of the outlet filter 9 is connected to the outlet of the polymer solution delivery system 5 to filter out impurities in the polymer solution. Simultaneously, the inlet filter 8 and the outlet filter 9 have a self-cleaning function. When the pressure difference between the inlet and outlet of the inlet filter 8 or the outlet filter 9 reaches 0.15 MPa, a backwashing procedure is automatically initiated: the backwashing water source is taken from the platform's freshwater system or pretreated seawater, and the filter screen is washed in the opposite direction to the filtration. The wastewater containing impurities generated during backwashing is automatically discharged into the platform's open discharge tank or wastewater collection system, and discharged after centralized treatment to meet standards. The entire process requires no manual intervention, ensuring continuous solution preparation and intelligent operation.

[0041] The surface liquid preparation device for profile control on small offshore platforms provided by this invention includes the following steps during operation: 1) Nitrogen sealing preparation of the system: Before liquid preparation, the entire system (including polymer storage and feeding system 1, polymer forced stretching system 2, polymer strong dispersion system 3, crosslinking agent mixing system 4 and conveying pipeline) is purged with nitrogen and maintained at a slight positive pressure of 0.1-0.3 barG; high-purity nitrogen is continuously introduced into each dynamic and static sealing point (such as the feed port, stirring shaft, and sampling port) to form a gas seal, and a nitrogen air curtain is activated at the feed port of hopper 11 to ensure that oxygen is isolated throughout the process. 2) Feeding and metering: Under nitrogen protection, the polymer raw materials are accurately metered from the polymer storage and feeding system 1 and then transported to the polymer forced stretching system 2 according to the set ratio; 3) Forced stretching and mixing swelling: In the polymer forced stretching system 2, the polymer is subjected to high-speed shearing and stretching, and is initially mixed with the injected solvent water and rapidly swells to form a uniform polymer premixed liquid. The entire cavity is covered with nitrogen. 4) Strong dispersion and dissolution: The polymer premixed liquid enters the polymer strong dispersion system 3, where the polymer is fully dissolved through high shear dispersion and turbulence, and a high-concentration polymer solution is prepared. Nitrogen is continuously introduced to isolate oxygen during the dispersion process. 5) Crosslinking agent supply and mixing: The crosslinking agent is precisely delivered to the crosslinking agent mixing system 4 according to the set ratio via the crosslinking agent pump. At the same time, the high-concentration polymer solution obtained in step 4) is introduced into the crosslinking agent mixing system 4. The two are mixed online in a nitrogen-sealed environment to form a profile adjustment system. 6) Delivery to the wellhead: The prepared profile control system is pressurized through the polymer solution delivery system 5 and continuously delivered to the injection wellhead through a nitrogen-protected closed pipeline.

[0042] Throughout the process, the automatic control system 6 monitors the pressure, flow rate, temperature, liquid level, and oxygen concentration parameters of each unit in real time, and performs closed-loop control on the nitrogen replenishment valve, feeding speed, tensile strength, dispersion speed, and crosslinking agent pump frequency to ensure that the device operates safely and efficiently under closed and oxygen-free conditions.

[0043] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and not to limit them. Although this application 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 or all of the technical features therein. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application, and they should all be covered within the scope of the claims and specification of this application. In particular, as long as there is no structural conflict, the various technical features mentioned in the embodiments can be combined in any way. This application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A ground-based liquid preparation device for profile control on a small offshore platform, characterized in that, It includes a polymer storage and feeding system, a polymer forced stretching system, a polymer strong dispersion system, a crosslinking agent mixing system, and a polymer solution delivery system, wherein: The polymer storage and feeding system includes a hopper equipped with a weight sensor, and the outlet of the hopper is connected in sequence to a screw feeder and a venturi tube. The polymer forced stretching system adopts a two-stage forced stretching gear disk structure. The first-stage forced stretching gear disk includes a first-stage rotor and a first-stage stator. The rotor teeth of the first-stage rotor adopt a boomerang-shaped coarse tooth structure, and the stator teeth of the first-stage stator adopt a dense tooth structure. The second-stage forced stretching gear disk includes a second-stage rotor and a second-stage stator. The second-stage rotor includes an outer ring rotor tooth and an inner ring rotor tooth. The outer ring rotor tooth adopts a polygonal coarse tooth structure, and the inner ring rotor tooth adopts a wedge-shaped coarse tooth structure. The second-stage stator includes an outer ring stator tooth and an inner ring stator tooth arranged coaxially. The outer ring stator tooth and the inner ring stator tooth are in contact with the outer ring rotor tooth and the inner ring rotor tooth, respectively. Liquid guide wheels are added inside both the first-stage rotor and the second-stage rotor. The polymer high-strength dispersion system includes a dispersion chamber, a dispersion bed, and a top-mounted drive motor. The dispersion bed consists of an inner grid tube, an outer grid tube, a bottom plate, and a dispersion bed mesh filled inside. A mandrel is installed inside the dispersion bed, and the mandrel extends vertically through the dispersion chamber and is connected to the top-mounted drive motor for transmission. The crosslinking agent mixing system includes multiple independently controlled crosslinking agent pumps. The outlet of the polymer strong dispersion system is connected to the inlet of the crosslinking agent pumps. Through the multiple crosslinking agent pumps, the crosslinking agent and the prepared polymer solution are mixed in the required proportion, and then transported to the wellhead through the polymer solution delivery system.

2. The surface liquid preparation device for profile control of a small offshore platform according to claim 1, characterized in that, The first-order rotor has 6-20 teeth arranged radially in a circular pattern, and the first-order stator has 300-400 teeth in a dense tooth structure. The outer ring rotor teeth, inner ring rotor teeth, outer ring stator teeth, and inner ring stator teeth are all designed with 20-40 teeth. The outer ring rotor teeth are arranged circumferentially along the outer edge of the second-order rotor, and the inner ring rotor teeth are arranged radially inside the outer ring rotor teeth.

3. The surface liquid preparation device for profile control of a small offshore platform according to claim 1, characterized in that, It also includes an automatic control system set up in the automation control room. The automatic control system is based on a PLC, which collects flow meter, pressure and liquid level signals in real time, and automatically adjusts the speed of the polymer feeding system, the stretching speed of the polymer forced stretching system, the dispersion speed of the polymer strong dispersion system, and the conveying frequency of the crosslinking agent pump and the screw feeder to achieve closed-loop precise control of the entire process. Meanwhile, the polymer storage and feeding system, polymer forced stretching system, polymer strong dispersion system, crosslinking agent mixing system and polymer solution delivery system are integrated in the liquid preparation room. The automated control room and the liquid preparation room adopt an integrated partition design. The liquid preparation room is designed according to the ordinary explosion-proof standard for marine applications, while the automated control room is designed according to the positive pressure explosion-proof standard for marine applications. The two operate independently and do not interfere with each other.

4. The surface liquid preparation device for profile control of a small offshore platform according to claim 1, characterized in that, The hopper consists of two independent hoppers connected in parallel, and the polymer forced stretching system is configured in two sets in parallel. The total processing capacity of the polymer forced stretching system is not less than 80 cubic meters per hour.

5. The surface liquid preparation device for profile control on a small offshore platform according to claim 1, characterized in that, The thickness of the dispersion bed wire mesh is designed to be 15-25cm, and the rotation speed of the high-power dispersion module is designed to be 500-1000rpm.

6. The surface liquid preparation device for profile control of a small offshore platform according to claim 1, characterized in that, The dispersion chamber of the polymer high-strength dispersion system is equipped with an electric heating rod for thermal degradation treatment when the polymer becomes clogged.

7. The surface liquid preparation device for profile control of a small offshore platform according to claim 1, characterized in that, The crosslinking agent mixing system employs a one-to-one independent control of multiple crosslinking agent pumps, enabling the simultaneous preparation of profile control systems with different concentrations for multiple injection wells.

8. The surface liquid preparation device for profile control of a small offshore platform according to claim 1, characterized in that, It also includes a nitrogen sealing system, which includes a nitrogen inlet and a micro-pressure control valve group located at the top of the polymer forced stretching system and the polymer strong dispersion system, and an annular nitrogen air curtain assembly located inside the feed port of the hopper, maintaining the oxygen content in the system below 0.1% throughout the liquid preparation process.

9. The surface liquid preparation device for profile control of a small offshore platform according to claim 8, characterized in that, The nitrogen sealing system is a skid-mounted structure that can be configured according to the platform's space requirements.

10. The surface liquid preparation device for profile control of a small offshore platform according to claim 1, characterized in that, It also includes an inlet filter and an outlet filter. The outlet of the inlet filter is connected to the inlet of the venturi tube to filter out impurities in the process feed water. The inlet of the outlet filter is connected to the outlet of the polymer solution delivery system to filter out impurities in the polymer solution. At the same time, the inlet filter and the outlet filter have a self-cleaning function. When the pressure difference between the inlet and outlet of the inlet filter or the outlet filter reaches 0.15 MPa, the backwashing program is automatically started. The backwashing water source is taken from the platform's freshwater system or pretreated seawater. The backwashing wastewater is automatically discharged into the platform's open discharge tank or wastewater collection system.

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