Anti-fouling device, equipment and method based on an oilfield water injection system

Abstract

The application provides a device, equipment and method for removing scale and preventing scale based on an oilfield water injection system. The device comprises a shell, water inlets and outlets arranged on the outer side walls of the two sides of the shell, a vacuum dosing port arranged on the shell, and a blowdown port arranged at the bottom end of the shell. A partition plate, a plurality of first grids and a plurality of second grids are arranged in the shell. The plurality of first grids and the plurality of second grids are arranged on the two sides of the partition plate. The grid size of the plurality of first grids is smaller than that of the plurality of second grids. The device can increase the flowing path and time of fluid, dynamically remove scale and prevent scale, reduce the scale removal and prevention procedures, effectively reduce the labor and cost, and improve the scale removal effect.

Description

Technical Field

[0001] This application relates to the field of oil production engineering technology, and in particular to a descaling and antiscaling device, equipment and method based on an oilfield water injection system. Background Technology

[0002] With the development of water injection in oilfields, the demand for water injection has increased, gradually shifting from a single water source to multiple sources. This leads to instability in the mixed injection water, making it prone to scaling. This scaling results in scale buildup on surface pipelines, wellbores, and formations, increasing injection pressure, reducing formation water absorption capacity, and severely affecting injection efficiency. Furthermore, with large-scale water injection development, the reservoir water cut increases significantly. The pressure and temperature changes of the produced fluid from the formation to the surface also lead to severe scaling, affecting normal production. Therefore, scaling is a common phenomenon in oilfields, especially in highly salinized oilfields, where the scaling problem is particularly prominent and poses a significant challenge to water injection development.

[0003] Currently, the common method for treating scale in oilfields is to add scale inhibitors. These inhibitors chelate with calcium and magnesium ions, increasing their solubility and preventing scale formation. However, due to the large volume of injection and production fluids in oilfields, large amounts of scale inhibitors need to be added multiple times during the descaling process. Furthermore, the scale must be filtered through filters of different pore sizes multiple times to achieve descaling, making the process cumbersome. In addition, inappropriate agent quality and maintenance practices can lead to poor scale prevention, and the scale-forming ions may remain in the solution, potentially leading to re-scaling with changes in the environment. Summary of the Invention

[0004] This application provides a descaling and antiscaling device, equipment and method based on an oilfield water injection system, to solve the technical problems of poor descaling and antiscaling effect, complicated descaling and antiscaling procedures, high manpower consumption and high cost in the prior art for descaling and antiscaling of oilfield water injection systems.

[0005] In a first aspect, embodiments of this application provide a descaling and antiscaling device based on an oilfield water injection system, comprising: a housing,

[0006] The outer walls on both sides of the shell are respectively provided with water inlet and water outlet, the shell is also provided with vacuum dosing port, and the bottom of the shell is provided with sewage outlet;

[0007] The housing is provided with a partition, a plurality of first grids, and a plurality of second grids; the plurality of first grids and the plurality of second grids are respectively disposed on both sides of the partition; the partition is respectively disposed on the drain outlet, and the partition divides the interior of the housing into a plurality of receiving spaces, allowing liquid to flow between the plurality of receiving spaces; the water inlet is disposed on one side of the plurality of first grids, and the water outlet is disposed on one side of the plurality of second grids;

[0008] The grid size on the plurality of first grids is smaller than the grid size on the plurality of second grids.

[0009] In one possible implementation, one end of the plurality of first grids is connected to the inner sidewall of the housing, and the other end of the plurality of first grids is connected to one side of the partition.

[0010] And / or, one end of the plurality of second grids is connected to the inner wall of the housing, and the other end of the plurality of second grids is connected to the other side of the partition.

[0011] In one possible implementation, the housing is further provided with a plurality of inclined plates;

[0012] One end of the inclined plate is connected to the edge of the drain outlet, and the other end of the inclined plate is connected to the inner wall of the housing.

[0013] In one possible implementation, the height of the partition is less than the height of the housing, such that liquid on one side of the partition can flow over the partition to the other side of the partition.

[0014] Secondly, embodiments of this application provide a descaling and anti-scaling device based on an oilfield water injection system, comprising: the device in any embodiment of the first aspect of this application, and a special metal anti-scaling short-circuit;

[0015] The special metal anti-scaling short connector is used to be installed in the water injection well, and the special metal anti-scaling short connector is used to prevent scale formation in the water injection well;

[0016] The special metal anti-scaling short connector is also connected to a dispensing tubing column.

[0017] In one possible implementation, the device further includes: a buffer tank and a plurality of filters;

[0018] The buffer tank is connected to the inlet of the device; one end of the plurality of filters is connected to the outlet of the device, and the other end of the plurality of filters is connected to the injection well;

[0019] The multiple filters are selected from walnut shell filters or cartridge filters.

[0020] In one possible implementation, the device further includes a plurality of booster pumps;

[0021] The plurality of booster pumps are respectively disposed between the buffer tank and the inlet, and between the outlet and the plurality of filters.

[0022] Thirdly, embodiments of this application provide a method for descaling and preventing scale based on an oilfield water injection system, comprising: the method using equipment from any embodiment of the second aspect of this application, and including the following steps:

[0023] The water quality of the water injected into the buffer tank is tested to determine the type of scale. Based on the type of scale, it is determined to add seed crystals and / or soluble salts, and the water is injected into the shell from the inlet.

[0024] The seed crystals and / or soluble salts are added into the housing through the vacuum dosing port, and the water is controlled to flow through the plurality of first grids and the plurality of second grids, flowing out from the outlet and into the water injection well.

[0025] In one possible implementation, the water flows out from the outlet and is injected into the injection well, further comprising:

[0026] The water flows out from the outlet, passes through the multiple filters, and flows into the water injection well.

[0027] In one possible implementation, the seed crystal is selected from any one of dolomite, calcite, or garnet;

[0028] And / or, the soluble salt is selected from any one of sodium chloride, calcium chloride, magnesium chloride, sodium sulfate, sodium bisulfate, or magnesium sulfate.

[0029] This application provides a descaling and antiscaling device, equipment, and method based on an oilfield water injection system. The device comprises a shell with an inlet and an outlet on its outer side walls, a vacuum dosing port, and a drain port at its bottom. Inside the shell are a partition, multiple first grids, and multiple second grids, each positioned on either side of the partition. The grid size of the first grids is smaller than that of the second grids. In practice, fluid is injected into the shell through the inlet, rising and passing through the first grids to descal the smaller particles. Scale buildup obstructs and deposits at the bottom of the casing. Fluid passes through baffles and multiple second grids, slowing the flow rate and direction, allowing larger scale particles to pass through the grids and settle at the bottom. In the oilfield water injection process, the device forms scale particles within the device by allowing water to flow through it, and filters scale particles of different sizes, thus achieving scale removal from the water flowing out of the device. Furthermore, the device can dynamically perform scale removal and prevention by increasing the flow path and time of the fluid, reducing the scale removal and prevention procedures, effectively reducing manpower and costs, while improving the scale removal effect. Attached Figure Description

[0030] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0031] Figure 1 Schematic diagram of the scale removal and prevention device based on the oilfield water injection system provided in the embodiments of this application Figure 1 ;

[0032] Figure 2 Schematic diagram of the scale removal and prevention device based on the oilfield water injection system provided in the embodiments of this application Figure 2 ;

[0033] Figure 3 Schematic diagram of the scale removal and prevention device based on the oilfield water injection system provided in the embodiments of this application Figure 3 ;

[0034] Figure 4 Schematic diagram of the scale removal and prevention device based on the oilfield water injection system provided in the embodiments of this application Figure 4 ;

[0035] Figure 5 A schematic diagram of the scale removal and prevention device based on an oilfield water injection system provided in this application embodiment;

[0036] Figure 6 A process flow diagram of a descaling and antiscaling method based on an oilfield water injection system provided in this application embodiment;

[0037] Figure 7 The embodiments provided in this application illustrate the variation of calcium sulfate scaling index and scaling amount with MOD river water mixing ratio. Figure 1 (T=37℃);

[0038] Figure 8 The embodiments provided in this application illustrate the variation of calcium sulfate scaling index and scaling amount with MOD river water mixing ratio. Figure 2 (T=90℃);

[0039] Figure 9 The examples provided in this application illustrate the variation of strontium sulfate scaling index and scaling amount with MOD river water mixing ratio. Figure 1 (T=37℃);

[0040] Figure 10 The examples provided in this application illustrate the variation of strontium sulfate scaling index and scaling amount with MOD river water mixing ratio. Figure 2 (T = 90℃).

[0041] Explanation of reference numerals in the attached figures:

[0042] 100 — Descaling and anti-scaling device;

[0043] 110 — Shell;

[0044] 120 — Vacuum dosing port;

[0045] 130 — Inlet;

[0046] 140 — Outlet;

[0047] 150 — First grille;

[0048] 160 — Second grille;

[0049] 170 — partition;

[0050] 180 — Inclined plate;

[0051] 190 — Sewage outlet;

[0052] 200 — Buffer tank;

[0053] 300 — Booster pump;

[0054] 400 — Filter;

[0055] 500 — Special metal anti-scaling short circuit;

[0056] 510————dispensing column;

[0057] 60 — Water injection well.

[0058] The accompanying drawings illustrate specific embodiments of this application, which will be described in more detail below. These drawings and descriptions are not intended to limit the scope of the concept in any way, but rather to illustrate the concept of this application to those skilled in the art through reference to particular embodiments. Detailed Implementation

[0059] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims.

[0060] In the description of this application, it should be understood that the terms "counterclockwise," "clockwise," "longitudinal," "lateral," "up," "down," "front," "back," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0061] With the development of water injection in oilfields, the demand for water injection has increased, gradually shifting from a single water source to multiple sources. This leads to instability in the mixed injection water, making it prone to scaling. This scaling results in scale buildup on surface pipelines, wellbores, and formations, increasing injection pressure, reducing formation water absorption capacity, and severely affecting injection efficiency. Furthermore, with large-scale water injection development, the reservoir water cut increases significantly. The produced oil fluids face pressure and temperature changes from the formation to the surface, also leading to severe scaling and impacting normal production. Therefore, scaling is a common phenomenon in oilfields, especially in highly salinized oilfields, where the scaling problem is particularly prominent and poses a significant challenge to water injection development.

[0062] Currently, the common method for treating scale in oilfields is to add scale inhibitors. These inhibitors chelate with calcium and magnesium ions, increasing their solubility and preventing scale formation. However, due to the large volume of injection and production fluids in oilfields, large amounts of scale inhibitors are required, and continuous addition is necessary. Inadequate agent quality and maintenance practices in the field can also lead to poor scale prevention. Furthermore, existing scale prevention methods are limited, leaving scale-forming ions in solution, which may re-form scale with changes in the environment. Ion removal technology can effectively remove scale-forming ions from solution, but its high cost prevents its widespread application in oilfields.

[0063] To improve scaling control in oilfields and reduce costs, this invention proposes a comprehensive scaling prevention method combining rapid, centralized scaling at designated points on the surface and special metal anti-scaling connectors in the wellbore. This method involves establishing a vertical scaling fluidized bed device on the surface and adding a chemical system. This system accelerates scaling, shortens scaling time, and allows injected water to quickly complete the scaling process within the fluidized bed device, achieving ion balance and thus preventing scaling from affecting surface pipelines, wellbore, and formation. Simultaneously, special metal anti-scaling connectors are installed on the stratified water injection tubing in the wellbore to prevent scaling problems caused by changes in temperature, pressure, and flow pattern within the wellbore, achieving the goal of scaling control in the oilfield water injection system.

[0064] This application provides a descaling and antiscaling device, equipment, and method for oilfield water injection systems, aiming to solve the technical problems of poor antiscaling effect, complicated antiscaling procedures, and high cost in the prior art for descaling and antiscaling in oilfield water injection systems.

[0065] The technical solution of this application and how the technical solution of this application solves the above-mentioned technical problems are described in detail below with specific embodiments. These specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments. The embodiments of this application will now be described with reference to the accompanying drawings.

[0066] Figure 1 This is a schematic diagram of a scale removal and prevention device based on an oilfield water injection system, provided as an embodiment of this application. Figure 1As shown, the device includes: a housing 110, with an inlet 130 and an outlet 140 respectively provided on the outer side walls of both sides of the housing 110; a vacuum dosing port 120 is also provided on the housing 110; and a drain port 190 is provided at the bottom end of the housing 110. The housing 110 contains multiple partitions 170, multiple first grids 150, and multiple second grids 160. The multiple partitions 170 are located on the drain port 190, and the multiple partitions 170 divide the interior of the housing 110 into multiple accommodating spaces, allowing liquid to flow between the multiple accommodating spaces. The multiple first grids 150 and multiple second grids 160 are respectively located on both sides of the partitions 170. The inlet 130 is located on one side of the multiple first grids 150, and the outlet 140 is located on one side of the multiple second grids 160. The grid size on the multiple first grids 150 is smaller than the grid size on the multiple second grids 160.

[0067] The casing 110 can be a drum-like structure with a certain volume. Its outer shell not only possesses excellent high-temperature resistance, maintaining stability under extreme temperature conditions, but also excellent corrosion resistance, effectively resisting the erosion of various chemicals and extending its service life. Furthermore, the interior of the casing 110 can also undergo special treatment to ensure that it maintains structural integrity and functional reliability when in contact with corrosive fluids or gases. This makes the casing 110 particularly suitable for harsh industrial environments, such as chemical plants, oil refineries, or high-temperature, high-pressure oil and gas extraction operations, providing safety and durability.

[0068] Inlet 130 and outlet 140 are respectively provided on the outer side walls of both sides of the housing 110, and are directly connected to the internal space of the housing 110 to ensure that the fluid can smoothly enter and exit the housing 110. In order to achieve precise control of fluid flow, valves can also be provided on the inlet 130 and outlet 140 respectively to regulate the inflow and outflow of liquid or gas, or to completely close them to prevent any unnecessary leakage or backflow, and ensure the safety and efficiency of the device.

[0069] A vacuum dosing port 120 is provided on the casing 110, facilitating the addition of various chemicals to the casing 110. Inorganic salts, descaling agents, and other chemical agents can be injected into the casing through the vacuum dosing port 120. In oilfield water injection systems, the vacuum dosing port 120 not only simplifies the chemical addition process but also effectively prevents air from entering the device through the vacuum environment. Preventing air ingress leads to an increase in dissolved oxygen in the water, which may weaken the effectiveness of the descaling agent or even cause adverse reactions such as corrosion. (Reference) Figure 1The vacuum dosing port 120 can be set at the top of the housing 110. By using the vacuum dosing port 120 at the top of the housing 110, the above-mentioned problems can be effectively avoided, ensuring that the agent plays its role under the best conditions, thereby improving the descaling and corrosion prevention effects.

[0070] refer to Figure 2 The vacuum dosing port 120 can also be set on any side of the housing 110 and on the same side as the water inlet 130. The vacuum dosing port 120 is set above the water inlet 130. Chemicals are added through the vacuum dosing port 120 to accelerate the scaling reaction of the sewage inside the housing 110.

[0071] The bottom end of the housing 110 is provided with a drain port 190, which is used to discharge the structural products generated inside the housing 110 into the housing 110. At the same time, it can keep the inside of the housing 110 clean and tidy, ensuring that the system is not subject to secondary contamination by dirt during the entire descaling process.

[0072] Multiple baffles 170 within the housing 110 can be positioned above the drain outlet 190. The number of baffles 170 can be one, two, or three, etc. For example, one baffle 170 can be positioned above the drain outlet 190. The baffles 170 divide the interior of the housing 110 into two accommodating spaces. One accommodating space is connected to the inlet 130, and the other accommodating space is connected to the outlet 140. Simultaneously, fluid can flow from one accommodating space to the other. During the descaling process, as the injection water flows from the inlet 130 into one accommodating space and then from one accommodating space into the other accommodating space and out through the drain outlet 140, the flow rate is slowed down. The fluid needs to pass over the baffles 170 to reach the other accommodating space. Under the action of the chemicals during this stage, some scale will be generated in one accommodating space. Under the influence of gravity, the scale will deposit at the drain outlet 190, achieving a highly efficient descaling effect.

[0073] A plurality of first grids 150 and a plurality of second grids 160 are respectively disposed between the inner wall of the housing 110 and the partition 170, and the plurality of first grids 150 and the plurality of second grids 160 are respectively disposed on both sides of the partition 170. The plurality of first grids 150 and the plurality of second grids 160 are provided with mesh holes of the same or different sizes. For example, two, three or four first grids 150 are provided on one side of the partition 170, and similarly, two, three or four second grids 160 are provided on the other side of the partition 170. The plurality of first grids 150 can prevent scale from passing through the grid under the drive of fluid flow, causing it to deposit at the drain port 190. The plurality of second grids 160 can slow down the fluid flow rate and flow direction, allowing scale in another containment space to pass through the mesh holes of the plurality of second grids 160 and settle at the drain port 190 at the bottom of the housing 110.

[0074] In another embodiment, the mesh size on the plurality of first grids 150 is smaller than the mesh size on the plurality of second grids 160. When fluid flows from one receiving space equipped with the plurality of first grids 150 to another receiving space equipped with the plurality of second grids 160, under the action of the agent, the particle size of the scale deposits in the first receiving space is smaller. To prevent scale particles from flowing into the other receiving space, the mesh aperture of the plurality of first grids 150 is set to be smaller. When the fluid is in the other receiving space, due to the longer action time of the agent, the particle size of the scale deposits becomes larger. To prevent these scale particles from being unable to pass through the mesh apertures of the plurality of second grids 160 and settling to the bottom of the housing 110, the mesh aperture of the plurality of second grids 160 is set to be larger. This also prevents scale particles from clogging the plurality of second grids 160 and affecting the descaling and anti-scaling effect of the system. Of course, those skilled in the art can adjust the mesh size of the plurality of first grids 150 and the plurality of second grids 160 according to actual conditions.

[0075] Furthermore, in yet another implementation, refer to Figure 3 and Figure 4 The descaling and anti-scaling device consists of multiple first grids 150 and multiple second grids 160. The grids on the first grids 150 and second grids 160 can be regularly or irregularly arranged. For example, the grids in the first grids 150 and second grids 160 are irregularly arranged, becoming sparser closer to the side wall of the shell 110, or there may be no grid at all. Alternatively, the shell 110 can be configured with a larger upper volume and a smaller lower volume, allowing wastewater to fully undergo a scaling reaction upon reaching the top of the shell 110. Then, multiple descaling devices connected in series can remove the scale, achieving excellent descaling and anti-scaling effects.

[0076] This application provides a scale prevention and descaling device based on an oilfield water injection system. The device comprises a shell with an inlet and an outlet on its outer side walls, a vacuum dosing port, and a drain port at the bottom. Inside the shell are a baffle, multiple first grids, and multiple second grids, each positioned on either side of the baffle. The grid size of the first grids is smaller than that of the second grids. In practice, fluid is injected into the shell through the inlet. The fluid rises and passes through the first grids, blocking smaller scale particles and causing them to settle at the bottom of the shell. The fluid then passes through the baffle and the second grids, slowing the flow rate and direction, allowing larger scale particles to pass through the second grids and settle at the bottom of the shell. This device dynamically prevents and descals by increasing the fluid's flow path and time, reducing the scale prevention and descaling procedures, effectively lowering manpower and costs, while simultaneously improving the descaling effect.

[0077] Furthermore, based on the above embodiments, such as Figure 1 As shown, the descaling and anti-scaling device is described in more detail. One end of a plurality of first grids 150 is connected to the inner wall of the housing 110, and the other end of the plurality of first grids 150 is connected to one side of the partition 170; and / or, one end of a plurality of second grids 160 is connected to the inner wall of the housing 110, and the other end of the plurality of second grids 160 is connected to the other side of the partition 170.

[0078] Multiple first grids 150 are disposed within the internal structure of the housing 110. One end of each grid is connected to the inner wall of the housing 110 via a detachable connection method such as a pin or clip, or by welding or bonding, ensuring the stability and durability of the grid. The other end is connected to one side of the partition 170, which not only enhances the overall rigidity of the structure but also optimizes the fluid flow path, enabling the fluid to effectively perform preliminary particle filtration and sedimentation as it passes through the first grids. Similarly, multiple second grids 160 are fixed at one end to the inner wall of the housing 110, providing support. The other end is connected to the other side of the partition 170, which further extends the fluid flow path and enhances the capture and sedimentation effect of larger particle scale by changing the flow direction and velocity. Through the cooperation of this dual-grid system, the device can achieve more efficient separation and deposition of scale of different particle sizes.

[0079] Furthermore, continuing as Figure 1 As shown, a plurality of inclined plates 180 are also provided inside the housing 110; one end of the inclined plate 180 is connected to the edge of the drain outlet 190, the other end of the inclined plate 180 is connected to the inner side wall of the housing 110, and the inclined plate 180 is located at the lower end of the inlet 130 or the outlet 140.

[0080] Within the internal structure of the housing 110, multiple inclined plates 180 are installed. One end of each inclined plate 180 is connected to the edge of the drain outlet 190 by welding, bonding, or other methods, while the other end of the inclined plate 180 is connected to the inner wall of the housing 110. This gives the inclined plate 180 a certain inclination, ensuring that when deposits fall onto the inclined plate 180, they can be smoothly guided to the drain outlet, achieving efficient discharge and cleaning. The angle of the inclined plate 180 optimizes the fluid flow path and the direction of deposit guidance. By increasing the fluid contact area and extending the flow path, the inclined plate 180 effectively promotes the sedimentation of particles, causing smaller scale particles to gradually aggregate and slide down to the drain outlet 190 during the flow process, improving descaling efficiency and reducing the frequency and difficulty of system maintenance.

[0081] Furthermore, such as Figure 1 As shown, the height of the partition 170 is less than the height of the housing 110, so that the liquid on one side of the partition 170 can flow over the partition 170 to the other side of the partition 170.

[0082] The height of the baffle 170 can be less than the overall height of the housing 110, thus forming a liquid flow channel inside the housing 110. When liquid is on one side of the baffle 170, its level can easily exceed the height of the baffle, allowing it to flow naturally to the other side. This not only promotes smooth liquid flow but also effectively utilizes gravity and the natural flow characteristics of the liquid, reducing dependence on external power and ensuring uniform distribution and full contact of the fluid inside the housing. Furthermore, it enhances the descaling and settling efficiency of the device. As the liquid flows through the baffle, the change in flow velocity and the extension of the flow path facilitate the settling of particles, making it easier for scale to be captured and deposited at the bottom. This not only improves the processing efficiency of the device but also reduces the risk of potential clogging and extends the service life of the device.

[0083] This application also provides a scale removal and prevention device based on an oilfield water injection system. For example... Figure 5 As shown, the device includes the descaling and anti-scaling device 100 in any of the above embodiments, and a special metal anti-scaling short-circuit 500; the special metal anti-scaling short-circuit 500 is used to be installed in the water injection well 60, and is used to prevent scale formation in the water injection well 60; a branch injection pipe string 510 is also connected to the special metal anti-scaling short-circuit 500.

[0084] The scale prevention and descaling device 100 and the special metal scale prevention short-circuit 500 can form a scale prevention and descaling device to address the scaling problem in the water injection well 60. The special metal scale prevention short-circuit 500 is installed inside the water injection well 60, exerting its unique scale prevention function. Through the properties of its special metal materials, such as 304 stainless steel, copper alloys, zinc alloys, copper-zinc alloys, titanium and titanium alloys, nickel-based alloys, Hastelloy, Inconel, zirconium and zirconium alloys, etc., it can effectively inhibit the formation of scale, ensuring the smooth and efficient operation of the water injection well. Regarding the selection of the special metal scale prevention short-circuit, any metal or alloy that can achieve the above-mentioned function can be used; those skilled in the art can make the selection according to actual needs, which will not be elaborated here.

[0085] The special metal anti-scaling connector 500 not only functions independently but also connects tightly with the injection string 510, forming an integrated anti-scaling and fluid management system. The connection of the injection string 510 enables stratified water injection in multi-layered reservoirs, further optimizing the overall performance of the injection well. This allows the system to control the injection volume and direction of water at different layers, preventing scaling problems caused by uneven water injection. Furthermore, it provides flexible operation and maintenance options. The connection between the special metal anti-scaling connector 500 and the injection string 510 not only simplifies the system's installation and operation but also improves the overall system's reliability and durability. The injection well 60 can maintain high efficiency and stability during long-term operation, reducing maintenance frequency and related costs.

[0086] After the device 100 removes and prevents scale, it uses a special metal anti-scaling short circuit 500 to further improve the scale removal and prevention effect, while saving procedures and simplifying operation.

[0087] Furthermore, such as Figure 5 As shown, the device also includes: a buffer tank 200 and multiple filters 400; the buffer tank 200 is connected to the inlet 130 of the device; one end of the multiple filters 400 is connected to the outlet 140 of the device, and the other end of the multiple filters 400 is connected to the injection well 60; the multiple filters 400 are selected from walnut shell filters or filter cartridge filters.

[0088] The buffer tank 200 works in conjunction with multiple filters 400 to ensure that the fluid is adequately treated and purified before entering the injection well 60. The buffer tank 200 can be directly connected to the inlet 130, serving as the initial receiving and regulating device to stabilize the fluid flow rate, absorb fluid pressure fluctuations, and ensure the smooth operation of subsequent processing. After initial regulation by the buffer tank 200, the fluid passes through device 100 and is then guided to the multiple filters 400 for further purification. One end of each filter 400 is tightly connected to the outlet 140 to ensure the fluid can smoothly enter the filtration stage. The other end of the filter 400 is connected to the injection well 60, and the filtered clean fluid is safely injected into the well.

[0089] The Filter 400 can be selected from different types according to specific needs, such as walnut shell filters or cartridge filters. Walnut shell filters have excellent adsorption capacity and durability, making them suitable for treating oily wastewater and removing suspended particles. Cartridge filters, on the other hand, provide high-precision filtration, effectively removing fine particles and impurities to ensure fluid purity. Thus, this equipment not only improves fluid quality but also extends the service life of injection wells, reduces the risk of scaling and clogging, and ensures the efficient operation of oilfield water injection equipment and the sustainable use of resources.

[0090] Furthermore, such as Figure 5 As shown, the device also includes multiple booster pumps 300; the multiple booster pumps 300 are respectively arranged between the buffer tank 200 and the inlet 130, and between the outlet 140 and multiple filters 400.

[0091] Multiple booster pumps 300 are used to ensure smooth flow and efficient treatment of fluid throughout the equipment. One or more booster pumps 300 are positioned between the buffer tank 200 and the inlet 130, primarily to increase the input pressure of the fluid, ensuring that the fluid can enter the buffer tank 200 quickly and stably, thereby achieving effective control and regulation of the flow rate. Other booster pumps 300 are installed between the outlet 140 and multiple filters 400, used to transport fluid from the buffer tank 200 to the filters 400, providing the necessary pressure to overcome the resistance of the filter media, ensuring that the fluid can smoothly pass through the filters for deep purification. This not only improves filtration efficiency but also ensures optimal filter operation and extends their service life.

[0092] This application also provides a method for scale removal and prevention based on an oilfield water injection system, such as... Figure 6 As shown, the method includes:

[0093] S601. Test the water quality of the water injected into the buffer tank 200 to determine the type of scale. Based on the type of scale, determine the addition of seed crystals and / or soluble salts, and inject the water into the shell 110 from the inlet 130.

[0094] To ensure the quality and effectiveness of the injected water, water quality testing is required in the buffer tank 200. Water quality testing technology can accurately analyze and identify the components and types of scale that may cause scaling, providing crucial data support for subsequent treatment steps. Once the type of scale is identified, appropriate treatment strategies can be developed based on its specific characteristics. For example, specific seed crystals and / or soluble salts can be added to the water to inhibit scale formation or promote the dissolution of existing scale. The addition of seed crystals can induce scale deposition at specific locations, thus preventing the formation of hard scale in critical equipment or pipelines, while the use of soluble salts can alter the chemical balance of the water, reducing the tendency to scale. After water quality adjustment, the treated injected water is introduced into the shell 110 through the inlet 130 to begin its circulation and further treatment within the device 100. This not only effectively prevents scale formation but also improves the overall efficiency and effectiveness of the injected water.

[0095] S602. Seed crystals and / or soluble salts are added into the shell 110 through the vacuum dosing port 120, and the water is controlled to flow through multiple first grids 150 and multiple second grids 160, and then flows out from the outlet 140 and is injected into the water injection well 60.

[0096] The vacuum dosing port 120 can precisely add specific seed crystals and / or soluble salts into the housing 110 based on previous water quality test results, optimizing the water's chemical properties to prevent scale formation or promote the dissolution of existing scale. After the seed crystals and / or soluble salts are added to the housing 110, the water injection fluid's treatment path begins as follows: First, the fluid flows through multiple first grids 150, effectively capturing and settling smaller particles while ensuring the seed crystals are evenly distributed in the fluid, inducing deposition. Next, the fluid continues to flow through multiple second grids 160, further slowing the flow rate and changing its direction, allowing larger scale particles to effectively settle to the bottom, improving scale removal efficiency and ensuring sufficient reaction of the seed crystals and soluble salts in the fluid. After multi-stage treatment, the purified and adjusted fluid flows out from the outlet 140 and is ultimately injected into the injection well 60, ensuring the well's efficient operation and long-term stability.

[0097] Furthermore, water flows out from outlet 140 and is injected into injection well 60, which also includes:

[0098] Water flows out from outlet 140, passes through multiple filters 400, and flows into injection well 60.

[0099] The 400 series of filters offers a variety of options to suit specific needs, including walnut shell filters and cartridge filters. Walnut shell filters are known for their excellent adsorption capacity and durability, effectively removing oil and suspended particles from fluids. Cartridge filters, on the other hand, provide high-precision filtration, ensuring the complete removal of fine particles and impurities.

[0100] Furthermore, the seed crystal is selected from any one of dolomite, calcite, or garnet; and / or, the soluble salt is selected from any one of sodium chloride, calcium chloride, magnesium chloride, sodium sulfate, sodium bisulfate, or magnesium sulfate.

[0101] The selection of seed crystal particle size range includes, but is not limited to, 10-30 mesh, 30-50 mesh, 50-80 mesh, 80-100 mesh, etc.

[0102] Specifically, the above method is used in the following example: An oilfield employs water injection development, with the injection water source being a mixture of produced water and river water. The produced water has high mineralization, with a total mineralization of 282,000 ppm, including 172,000 ppm chloride ions, 13,700 ppm calcium ions, and 494 ppm sulfate ions. The river water has a total mineralization of 54,000 ppm, including 901 ppm calcium ions and 7,570 ppm sulfate ions. The two are mixed in different proportions and injected into the wellbore, with a daily injection volume of 38,955 tons.

[0103] Table 1. Complete composition analysis of injected water

[0104]

[0105]

[0106] Note: Sodium (Na + ), potassium (K) + ), magnesium (Mg) 2+ ), calcium (Ca 2+ ), Strontium (Sr) 2+ ), barium (Ba 2+ Total iron (Fe) 2+ Chloride (Cl) - ), sulfate (SO4) 2- ), bicarbonate (HCO3) - ), percentage of carbon dioxide in the gas, total dissolved solids (TDS), and pH.

[0107] Firstly, using OLI software to predict the scaling trend and scale amount of the injected water, it was found that mixing the two types of water would produce a large amount of sulfate scale. The scaling trend and scale amount are as follows: Figures 7-10 As shown.

[0108] Figures 7-10It is a trend chart of scaling index and scaling amount using two types of injection water from a certain oilfield under different mixing ratios and temperature conditions. Figure 7 The graph shows the calcium sulfate scaling index and scale amount at 37℃ (simulated ground temperature) under different MOD river water mixing ratios. The results indicate that as the MOD river water ratio increases, both the calcium sulfate scaling index and scale amount first increase and then decrease. When the MOD river water mixing ratio increases to 60%, the scale amount reaches as high as 2250 mg / L. The colors in the graph represent the severity of scaling; darker colors indicate more severe scaling. Figure 8 The results show that the calcium sulfate scaling index and scaling amount at 90℃ (simulated formation temperature) under different MOD river water mixing ratios are displayed. The results show that as the MOD river water ratio increases, the calcium sulfate scaling index and scaling amount first increase and then decrease. When the MOD river water mixing ratio increases to 60%, the decoupling improvement is the greatest, reaching 4100 mg / L. Figure 9 and Figure 10 The display shows the strontium sulfate scaling index and scaling amount of the two mixed waters under ground and formation temperature conditions.

[0109] In the laboratory, produced water and river water were prepared separately, with a 4:6 ratio of produced water to river water. After mixing, a scale accelerator was added, and the scale formation amount and time were tested at different time points until the scale formation amount stabilized, at which point the scaling reaction was considered complete. Garnet and sodium sulfate were selected as suitable scale accelerators for this system through experiments, with an addition concentration of 1-2 g / L garnet + 0.01-0.05 mg / L sodium sulfate. The indoor scaling time was tested at 15-30 minutes. The scale was added to a targeted scaling device through a vacuum dosing port. The scaling products were calcium sulfate and strontium sulfate, with inorganic scale particles ranging from 1-10 μm in size; therefore, a two-stage filter was used: a walnut shell filter and a cartridge filter. Due to the high mineralization of the injected water, the large amount of scale formation, the large daily treatment capacity, and the short surface treatment time, it is difficult to ensure that the scaling reaction of the high-mineralized water is complete. In addition, the temperature and pressure increase in the wellbore, and the amount of calcium sulfate scale formation increases, especially at the water nozzle of the distributor in the injection string. Therefore, a special metal anti-scaling short-circuit is installed above the injection string to effectively prevent scaling in the injection string and ensure the injection volume.

[0110] It should be noted that, for the sake of simplicity, the foregoing method embodiments are all described as a series of actions. However, those skilled in the art should understand that this application is not limited to the described order of actions, as some steps may be performed in other orders or simultaneously according to this application. Furthermore, those skilled in the art should also understand that the embodiments described in the specification are all optional embodiments, and the actions and modules involved are not necessarily essential to this application.

[0111] The various embodiments or implementation methods described in this specification are presented in a progressive manner. Each embodiment focuses on the differences from other embodiments, and the same or similar parts between the embodiments can be referred to each other.

[0112] It should be noted that phrases such as "in specific implementations," "in some embodiments," "in this embodiment," and "exemplarily" in the specification indicate that the described embodiments may include specific features, structures, or characteristics, but not every embodiment necessarily includes that specific feature, structure, or characteristic. Furthermore, such phrases do not necessarily refer to the same embodiment. Moreover, when a specific feature, structure, or characteristic is described in connection with an embodiment, implementing such a feature, structure, or characteristic in conjunction with other embodiments, whether explicitly described or not, is within the knowledge scope of those skilled in the art.

[0113] Generally speaking, terms should be understood at least in part by their use in context. For example, at least in part by context, the term "one or more" as used in the text can be used to describe any feature, structure, or characteristic of the singular meaning, or a combination of features, structures, or characteristics of the plural meaning. Similarly, at least in part by context, terms such as "a" or "the" can also be understood to convey either singular or plural usage.

[0114] It should be readily understood that the terms “on,” “above,” and “on top of” in this disclosure should be interpreted in the broadest possible sense, such that “on” means not only “directly on something” but also “on something” with an intermediate feature or layer therebetween, and that “above” or “on top of” means not only “on top of something” but also “on top of something” without an intermediate feature or layer therebetween (i.e., directly on something).

[0115] Furthermore, for ease of explanation, spatial relative terms may be used herein. These terms are intended to encompass different orientations of the device in use or operation other than those shown in the accompanying drawings. The device may have other orientations (rotated 90 degrees or in other orientations), and the spatial relative descriptive terms used herein can be interpreted accordingly. In the above embodiments, the descriptions of each embodiment have their own emphasis; parts not detailed in a particular embodiment can be referred to in the relevant descriptions of other embodiments. The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described; however, as long as these combinations of technical features do not contradict each other, they should be considered within the scope of this specification.

[0116] Furthermore, in the description of this invention, it should be noted that the terms "front," "rear," etc., indicating orientation or positional relationship are based on orientation or positional relationship, or the orientation or positional relationship commonly used when the product of the invention is in use. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention. In addition, the terms "first," "second," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0117] Other embodiments of this application will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of this application that follow the general principles of this application and include common knowledge or customary techniques in the art not disclosed herein.

[0118] It should be understood that this application is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of this application is limited only by the appended claims.

Claims

1. A method for descaling and preventing scale based on an oilfield water injection system, characterized in that, include: Shell (110) The outer walls on both sides of the housing (110) are respectively provided with an inlet (130) and an outlet (140), a vacuum dosing port (120) is provided at the top of the housing (110), and a drain port (190) is provided at the bottom of the housing (110). The housing (110) is provided with a partition (170), a plurality of first grids (150) and a plurality of second grids (160); the partition (170) is disposed on the drain outlet (190), the height of the partition (170) is lower than the height of the housing (110), and the partition (170) divides the interior of the housing (110) into a plurality of receiving spaces to extend the water flow path, so that the liquid can flow between the plurality of receiving spaces; the plurality of first grids (150) and the plurality of second grids (160) are respectively disposed on both sides of the partition (170); the inlet (130) is disposed on one side of the plurality of first grids (150), and the outlet (140) is disposed on one side of the plurality of second grids (160); The grid size on the plurality of first grids (150) is smaller than the grid size on the plurality of second grids (160). The first grids (150) are used to block the scale particles with smaller particle size and deposit them to the bottom of the housing (110), preventing the scale particles in one containment space where the first grid (150) is located from flowing into another containment space where the second grid (160) is located. The second grids (160) are used to slow down the fluid flow rate and flow direction, so that the scale in the other containment space passes through the grid holes of the plurality of second grids (160) and settles to the drain port (190) at the bottom of the housing (110). Seed crystals are added into the housing (110) through the vacuum dosing port (120), and water is controlled to flow through the plurality of first grids (150), the plurality of second grids (160), and the water flows out from the outlet (140) and into the water injection well (60).

2. The method according to claim 1, characterized in that, One end of the plurality of first grids (150) is connected to the inner wall of the housing (110), and the other end of the plurality of first grids (150) is connected to one side of the partition (170); And / or, one end of the plurality of second grids (160) is connected to the inner wall of the housing (110), and the other end of the plurality of second grids (160) is connected to the other side of the partition (170).

3. The method according to claim 2, characterized in that, The housing (110) is also provided with a plurality of inclined plates (180); One end of the inclined plate (180) is connected to the edge of the drain outlet (190), and the other end of the inclined plate (180) is connected to the inner wall of the housing (110). The inclined plate (180) is located at the lower end of the inlet (130) or the outlet (140).

4. The method according to claim 2, characterized in that, This allows the liquid located on one side of the partition (170) to flow over the partition (170) to the other side of the partition (170).

5. The method according to claim 1, characterized in that, The method also includes a special metal anti-scaling short circuit (500). The special metal anti-scaling short connector (500) is used to be installed in the water injection well (60) to prevent scale formation in the water injection well (60); The special metal anti-scaling short connector (500) is also connected to a dispensing pipe string (510).

6. The method according to claim 5, characterized in that, Also includes: Buffer tank (200) and multiple filters (400); The buffer tank (200) is connected to the inlet (130); one end of the plurality of filters (400) is connected to the outlet (140), and the other end of the plurality of filters (400) is connected to the injection well (60).

7. The method according to claim 6, characterized in that, It also includes multiple booster pumps (300); The plurality of booster pumps (300) are respectively disposed between the buffer tank (200) and the inlet (130), and between the outlet (140) and the plurality of filters (400).

8. The method according to claim 1, characterized in that, Includes the following steps: The water quality of the water injected into the buffer tank (200) is tested to determine the type of scale. Based on the type of scale, seed crystals are added, and water is injected into the shell (110) from the inlet (130).

9. The method according to claim 7, characterized in that, The water flowed from the outlet (140) and was injected into the injection well (60), and also included: The water flows out from the outlet (140), passes through the plurality of filters (400), and flows into the water injection well (60).

10. The method according to claim 8, characterized in that, The seed crystal is selected from any one of dolomite, calcite, or garnet.

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