A detection method and detection device for the replacement requirement of an oilfield produced water filter plate

Abstract

The present invention discloses a detection method and a detection device for the replacement requirement of an oilfield produced water filter plate, including: S1. Collect data in real time according to the filtration state of the filter plate to determine the first flow rate at the water intake inlet and the second flow rate at the filtration outlet; S2. Judge whether to start the flushing step according to the obtained first flow rate and second flow rate; S3. Calculate the change rate and passing ratio of the passing property of the flushing liquid according to the real-time monitoring data of the flow rate in the flushing step; S4. Calculate the change rate of the real-time current of the filter plate, the replacement coefficient and the average change rate of the current under the flushing state according to the real-time monitoring data of the resistance in the flushing step; S5. Measure the weight of the solid particles on the filter support plate in the buffer chamber after flushing and judge the change rate of the solid particle weight according to the historical data; S6. Judge the service life of the filter plate. The present invention can accurately and scientifically judge whether the filter plate needs to be replaced under the condition of non-stop operation.

Description

Technical Field

[0001] The present invention belongs to the technical field of detection of oilfield produced water treatment devices, and particularly relates to a detection method and a detection device for the replacement requirement of an oilfield produced water filter plate. Background Art

[0002] With the progress of oilfield water injection development and production, the treatment and discharge of injected water and oily sewage have attracted more and more attention. For example, the oil production of Daqing Oilfield in China exceeded 46 million tons in 2004, and the reinjection water volume reached more than 500 million tons. Due to the use of various oilfield exploitation aids, the water quality of oilfield produced water has a larger variation range. It is difficult for the treated produced oil sewage in some blocks to meet the standards, and it is still forced to be reinjected. However, if the reinjected water does not meet the requirements but is still reinjected underground, it will lead to the blockage of the oil outlet channels of the formation, low water injection efficiency, and oil production volume. In addition, if the discharged water does not meet the standards, it will not only cause environmental pollution, damage water bodies, and affect the ecological balance, but also cause a large amount of water resource waste. Therefore, the treatment of oilfield produced water is of great significance for environmental protection, water resource reuse, and promoting sustainable economic development.

[0003] In the process of produced fluid treatment, pre-separation, as the first process of produced fluid treatment, functions to remove sediment and separate oil and water, avoiding the blockage or abrasion of equipment by sediment and large flocculent oil droplets in subsequent processes, obtaining a liquid with a higher water content through efficient oil-water separation, and thus improving the efficiency of subsequent processes. Therefore, the pre-separation technology plays an important role in the treatment of produced fluid.

[0004] Most pre-separation equipment uses filter plates to preliminarily filter produced water. Due to long-term use, the filter plates may have defects in material structure or blockage of through holes by blockages, resulting in filter plate failure or too low passing rate, which is not conducive to use. Although backwashing technology has emerged now, which can remove some blockages, in actual use, there is a lack of technology to judge the service life of the filter plate and determine whether the filter plate needs to be replaced in the state of non-stop disassembly. Currently, the main methods for judging whether the filter plate needs to be replaced are still based on experience or shutdown inspection, and these two methods are likely to cause material waste or reduced production efficiency.

[0005] In the prior art, there are a small number of automatic judgment methods. For example, CN100337717C discloses a filter element life detection method for a water purifier. Through converting the water production time into a filter element life segment value and comparing it with a preset life value, people can timely know the usage status of the filter element and replace the filter element as needed. CN111760367A discloses a filter element life detection method, device, intelligent terminal and storage medium. This life judgment method compares the current water production rate with the reference water production rate threshold of the filter element life, and then obtains the detection information of the filter element life. However, the existing judgment methods do not comprehensively consider all failure factors of the filter plate, and the calculation method fails to achieve accuracy and objectivity.

[0006] In summary, there is an urgent need to provide a detection method for the replacement requirement of the oilfield produced water filter plate, which can accurately and scientifically judge whether the filter plate needs to be replaced under the condition of non-stop operation. Summary of the Invention

[0007] To solve the above technical problems, the present invention provides a detection method and a detection device for the replacement requirement of the oilfield produced water filter plate. This test method can accurately and scientifically judge whether the filter plate needs to be replaced under the condition of non-stop operation.

[0008] To achieve the above object, the present invention provides the following technical solutions:

[0009] A detection method for the replacement requirement of the oilfield produced water filter plate includes the following steps:

[0010] S1. Collect data in real time according to the filtration state of the filter plate to determine the first flow rate L at the water intake inlet 1i and the second flow rate L at the filtration outlet 2i ;

[0011] S2. According to the first flow rate L 1i and the second flow rate L 2i obtained in step S1, calculate the permeability change rate Ki and the passing ratio Ai of the filter plate, and judge whether to start the flushing step;

[0012] S3. According to the real-time monitoring data of the flow rate of the flushing step in step S2, determine the third flow rate L3i at the flushing liquid inlet and the fourth flow rate L4i at the flushing liquid outlet, and calculate the permeability change rate Ji and the passing ratio ;

[0013] S4. According to the real-time monitoring data of the resistance of the flushing step in step S2, determine the real-time current I of the metal inside the filter plate i , calculate the change rate H i of the real-time current of the filter plate, the replacement coefficient Ci and the average current change rate Di under the flushing state;

[0014] S5. When the flushing step reaches the preset duration, end the flushing step, measure the weight Gk of the solid particles on the filter support plate of the buffer chamber after flushing, and judge the change rate E of the solid particle weight according to historical data;

[0015] S6. According to the passing ratio obtained in step S3 , the change rate Hi of the real-time current of the filter plate, the replacement coefficient Ci, the average change rate Di of the current in the flushing state, and the change rate E of the solid particle weight obtained in step S5, judge the service life of the filter plate.

[0016] The present invention also provides a special detection device manufactured for implementing the detection method for the replacement requirement of the oilfield produced water filter plate.

[0017] The detection device includes a filter, a flushing water tank, a buffer chamber, a resistance measurement module, a weight measurement module and a host computer;

[0018] The filter includes a filter cavity, a filter plate, and two clamping contact parts respectively located on the upper and lower inner surfaces of the cavity,

[0019] The upper and lower edges of the filter plate are clamped in the card slots of the clamping contact parts, so as to realize the fixation of the filter plate;

[0020] At least two conductive contact points are arranged in the card slot inside the clamping contact part.

[0021] A filter support plate and a weight detection device are arranged in the buffer chamber. The filter support plate is a hollowed-out plate installed in the buffer chamber; the weight detection device is arranged at the center position of the lower surface of the filter support plate.

[0022] The produced liquid inlet of the filter cavity is connected to the host computer through a first valve and a first flowmeter. The filtered outlet of the filter cavity is connected to the host computer through a second valve and a second flowmeter. The flushing liquid inlet of the filter cavity is respectively connected to the host computer and the flushing water tank through a third valve and a third flowmeter. The flushing liquid outlet of the filter cavity is respectively connected to the host computer and the buffer chamber through a fourth valve and a fourth flowmeter.

[0023] One end of the resistance measurement module is connected to the conductive contact point inside the card slot of the clamping contact part, and the other end is connected to the host computer;

[0024] One end of the weight measurement module is connected to the weight detection device of the buffer chamber, and the other end is connected to the host computer.

[0025] Preferably, the filter plate has a framework formed of metallic foam and an elastic medium layer coated outside the framework; more preferably, there are at least two metal exposed points on the filter plate, and the metal exposed points are in contact with the conductive contacts.

[0026] Preferably, the weight gravity detection device can be a spring, a piezoelectric material, or other components capable of converting gravity into other measurable signals.

[0027] Preferably, the resistance measurement module further includes a fusing mechanism, which can be a fuse, so as to avoid large current caused by short circuit of the resistance measurement circuit when the degree of peeling of the elastic medium layer on the surface of the filter plate is large and the area of direct contact between the metal and the liquid is too large, which may damage the internal instruments of the circuit. When the fusing mechanism is fused, it indicates that the filter life is complete and needs to be replaced.

[0028] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0029] The detection method for the replacement requirement of the oilfield produced water filter plate of the present invention can accurately and scientifically judge whether the filter plate needs to be replaced under the condition of non-stop operation. Description of the Drawings

[0030] Figure 1 It is a schematic diagram of the special detection device of the present invention.

[0031] Wherein, 1. Filter, 2. Flushing water tank, 3. Buffer chamber, 4. Resistance measurement module, 5. Weight measurement module, 6. Host computer, 7. First valve and first flowmeter, 8. Second valve and second flowmeter, 9. Third valve and third flowmeter, 10. Fourth valve and fourth flowmeter, 1-1. Produced water inlet, 1-2. Filtration outlet, 1-3. Flushing liquid inlet, 1-4. Flushing liquid outlet, 1-5. Clamping contact part, 1-6. Filter plate. Detailed Embodiments

[0032] The following will clearly and completely describe a test method for static viscosity reduction applicable to chemical cold production of ultra-heavy oil of the present invention with reference to specific embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0033] Before further describing the specific embodiments of the present invention, it should be understood that the protection scope of the present invention is not limited to the following specific embodiments; it should also be understood that the terms used in the embodiments of the present invention are for the purpose of describing specific embodiments, rather than limiting the protection scope of the present invention.

[0034] A detection method for the replacement requirement of an oilfield produced water filter plate, comprising the following steps:

[0035] S1. Collect data in real time according to the filtration state of the filter plate, and determine the first flow rate L at the water intake inlet 1i and the second flow rate L at the filtration outlet 2i ;

[0036] S2. According to the first flow rate L obtained in step S1 1i and the second flow rate L 2i , calculate the permeability change rate Ki and the passing ratio Ai of the filter plate, and determine whether to start the flushing step;

[0037] Among them, the calculation formula for the permeability change rate Ki is:

[0038] ;

[0039] The calculation formula for the passing ratio Ai is: ;

[0040] Among them, i is the number of times of real-time collection, and i is greater than or equal to 2.

[0041] The determination method is: when K i-4 , K i-3 , K i-2 , K i-1 , K i all fall within the range of 90-110%, and A i is less than the first threshold α, start the flushing step, otherwise do not start, and the value of the first threshold α is 1.8-2.

[0042] S3. According to the real-time monitoring data of the flow rate in the flushing step described in step S2, determine the third flow rate L3i at the flushing liquid inlet and the fourth flow rate L4i at the flushing liquid outlet, and calculate the permeability change rate Ji and the passing ratio of the flushing liquid ;

[0043] The calculation formula for the permeability change rate Ji of the flushing liquid is:

[0044] ,

[0045] Among them, i is the number of times of real-time collection, and i is greater than or equal to 2.

[0046] The calculation method is:

[0047] When Ji-4, Ji-3, Ji-2, Ji-1, Ji all fall within the range of 90-110%, calculate according to the following formula:

[0048] 。

[0049] S4. Determine the real-time current I of the metal inside the filter plate based on the real-time monitoring data of the resistance during the flushing step in step S2 i , and calculate the change rate H of the real-time current of the filter plate i , replacement coefficient Ci, and the average change rate Di of the current under the flushing state;

[0050] The H i is calculated by the formula: ;

[0051] The C i is calculated as follows:

[0052] When |H i-4 |, |H i-3 |, |H i-2 |, |H i-1 |, |H i | are all less than 10%, then calculate according to the following formula:

[0053] C i =I i / I0;

[0054] where I0 is the initial current, which is a device constant measured during the initial equipment assembly and debugging.

[0055] The Di is calculated as follows:

[0056] If until the end of flushing, the change rate of the real-time current Ii never reaches the condition that |Hi-4|, |Hi-3|, |Hi-2|, |Hi-1|, |Hi| are all less than 10%, then calculate according to the following formula:

[0057] ;

[0058] where n is the total number of measurements, and i represents the i-th measurement.

[0059] S5. When the flushing step reaches the predetermined duration, end the flushing step, measure the weight Gk of the solid particles on the filter support plate in the buffer chamber after flushing, and judge the change rate E of the solid particle weight based on historical data;

[0060] The formula for calculating the change rate E of the solid particle weight is:

[0061] E = |Gk - Gk-1| / Gk-1;

[0062] where k is the number of flushing times.

[0063] S6. According to the passing ratio obtained in step S3 , based on the change rate Hi of the real-time current of the filter plate obtained in step S4, the replacement coefficient Ci, the average change rate Di of the current in the flushing state, and the change rate E of the solid particle weight obtained in step S5, determine the service life of the filter plate;

[0064] The method for judging the service life of the filter plate is specifically as follows:

[0065] When less than or equal to , it is determined that the service life of the filter plate has not expired and it can continue to be used;

[0066] When greater than , further judge the resistance monitoring situation, where a, n, b, and d are all constant values set according to experience;

[0067] If any of the following is satisfied, it is determined that the service life of the filter plate has not expired and it can continue to be used; otherwise, the service life of the filter plate of this filter has expired and needs to be replaced;

[0068] 1) C i is between 0.8 and 1.2, or D i is between 0.9 and 1.4 and H i are all less than 5;

[0069] 2) E is less than 15%.

[0070] As Figure 1 shown, the present invention also provides a special detection device manufactured for implementing the detection method for the replacement requirement of the oilfield produced water filter plate.

[0071] The detection device includes a filter 1, a flushing water tank 2, a buffer chamber 3, a resistance measurement module 4, a weight measurement module 5, and a host computer 6;

[0072] The filter 1 includes a filter cavity, a filter plate 1-6, and two clamping contact parts 1-5 respectively located on the upper and lower inner surfaces of the cavity,

[0073] The upper and lower edges of the filter plate 1-6 are clamped in the card slots of the clamping contact part 1-5, so as to realize the fixation of the filter plate;

[0074] At least two conductive contact points are arranged in the card slot inside the clamping contact part 1-5.

[0075] A filter support plate and a weight detection device are arranged in the buffer chamber 3. The filter support plate is a hollow plate installed in the buffer chamber; the weight detection device is arranged at the center position of the lower surface of the filter support plate.

[0076] The extraction liquid inlet 1-1 of the filter cavity is connected to the upper computer 6 through a first valve and a first flowmeter 7. The filtered outlet 1-2 of the filter cavity is connected to the upper computer 6 through a second valve and a second flowmeter 8. The flushing liquid inlet 1-3 of the filter cavity is connected to the upper computer 6 and the flushing water tank 2 respectively through a third valve and a third flowmeter 9. The flushing liquid outlet 1-4 of the filter cavity is connected to the upper computer 6 and the buffer cavity 3 respectively through a fourth valve and a fourth flowmeter 10.

[0077] One end of the resistance measurement module 4 is connected to the conductive contact inside the slot of the clamping contact part 1-5, and the other end is connected to the upper computer 6.

[0078] One end of the weight measurement module 5 is connected to the weight detection device of the buffer cavity 3, and the other end is connected to the upper computer 6.

[0079] Preferably, the filter plate 1-6 has a skeleton formed of porous metal and an elastic medium layer coated outside the skeleton. Further preferably, there are at least two metal exposure points on the filter plate 1-6, and the metal exposure points are in contact with the conductive contacts.

[0080] More preferably, the filter plate used in the present invention has a special structural configuration. Specifically, the filter plate has a skeleton formed of porous metal composed of shape memory alloy and an elastic medium layer coated outside the skeleton. The shape memory alloy is a CuAlNi alloy, and its deformation temperature is about 30°C, with a two-way memory effect, that is, it returns to the high-temperature shape when heated and returns to the low-temperature shape when cooled.

[0081] The manufacturing method of the filter plate includes: mixing Cu powder (44.62 wt%), Al powder (39.32 wt%) and Ni powder (16.06 wt%), and after fully mixing by ball milling, adding a pore former NH4Cl and then mixing again. Preferably, the addition amount of the pore former NH4Cl is 4.52 mol of the pore former NH4Cl per 1 g of the mixed metal powder. Pour the mixture into a heat-conducting container with an internal accommodation size of 40 cm * 30 cm * 20 cm (length * width * height), and place the heat-conducting container in a vacuum chamber for sintering. The sintering temperature is 1300 degrees Celsius, and the sintering time is 3-4 hours to form a porous metal plate of CuAlNi shape memory alloy, which has a pore size with an average diameter of 1-1.5 mm and a porosity of 76-80%.

[0082] Install the foamed metal sheet on a material stretching device, and slowly stretch the foamed metal sheet along the length direction of the sheet by the material stretching device. The stretching speed is 2.7 - 3 mm / min, and the stretching force is 500 - 600 N. Perform 10 equal-amplitude stretches on the foamed metal sheet, with each stretching length being 0.5 - 0.8 cm. After stretching, heat the foamed metal sheet to 950 degrees Celsius, keep it warm for half an hour, then perform quenching. After cooling, heat it to 950 degrees Celsius for 1 hour to obtain pore sizes with an average diameter of 3 - 5 mm and a porosity of 78 - 86%.

[0083] Immerse the above-mentioned foamed metal sheet in a silicone rubber mixed solution dissolved in a solvent and then take it out. Preferably, the solvent can be n-hexane. The viscosity of the above-mentioned silicone rubber mixed solution dissolved in the solvent is lower than 6×10 -3 Pa·s. Use a blowing system to blow repeatedly to remove the excess silicone rubber mixed solution, and only retain the thin layer of the silicone rubber mixed solution medium attached to the foamed metal sheet skeleton. Put the foamed metal sheet with the medium thin layer into a drying oven to dry the solvent and cure it. The drying temperature is 80 - 100 °C, thus obtaining the described filter plate.

[0084] Whenever the above-mentioned filter plate is below the deformation temperature (30 °C), it has the stretched shape, that is, it has a larger average pore size and porosity. And whenever the temperature rises above the deformation temperature (30 °C), shape memory deformation will occur and it will return to the shape before stretching, that is, it has a smaller average pore size and porosity. Since silicone rubber has a certain elasticity, the silicone rubber medium thin layer can change with the size of the pore diameter.

[0085] Since the temperature of the general produced oilfield fluid is relatively high, usually 40 - 70 °C, the temperature of the produced fluid is higher than the deformation temperature of the filter plate. That is to say, when the 40 - 70 °C produced fluid contacts the filter plate, since the temperature of the filter plate reaches above the deformation temperature, the filtration pore diameter of the filter plate will shrink, thus providing a good solid particle filtration effect.

[0086] The filter plate is vertically installed in the corresponding card slots of the clamping contact part, and at least two points on the filter plate are processed to expose the internal metal of the filter plate. For example: at two rectangular corners on any diagonal of the rectangular shape of the filter plate, remove the surface silicone rubber elastic medium layer by means such as grinding to expose the internal metal structure. And contact the exposed structure with the conductive contacts inside the card slots of the clamping contact part, so that the porous metal inside the filter plate is connected to a resistance measurement conductive circuit.

[0087] The above-mentioned resistance measurement conductive loop is a closed loop composed of a porous metal inside the filter plate as the measured resistance, and conductive contacts inside the upper and lower clamping contact parts, connecting leads, a constant voltage source and an ammeter in the resistance measurement module. The resistance measurement module further sends current data signals to the host computer.

[0088] Preferably, the weight gravity detection device can be a spring, a piezoelectric material or other components that can convert gravity into other measurable signals.

[0089] Preferably, the resistance measurement module 4 further includes a fusing mechanism, which can be a fuse, so as to avoid large currents caused by short circuits in the resistance measurement loop when the degree of peeling of the elastic medium layer on the surface of the filter plate is large and the area of direct contact between the metal and the liquid is too large, which may damage the internal instruments of the circuit. When the fusing mechanism is fused, it indicates that the filter life is complete and needs to be replaced.

[0090] The following is a detailed introduction to the detection method for the replacement requirement of the oilfield produced water filter plate provided by this application in combination with the detection device. The method includes:

[0091] S1. Real-time data acquisition of the filtration state of the filter plate, specifically including:

[0092] In the normal startup working state, the host computer opens and keeps the first valve at the produced water inlet and the second valve at the filtration outlet open, and simultaneously measures the first flow rate L 1i at the produced water inlet and the second flow rate L i2 at the filtration outlet in real time, and sends the above data to the host computer.

[0093] S2. Judging and starting the flushing step, specifically including:

[0094] The host computer calculates the change rate of passability 1i according to the first flow rate L 2i and the second flow rate L , and the ratio , where i is the number of times of real-time acquisition, and i is greater than or equal to 2. When K i-4 , K i-3 , K i-2 , K i-1 , K i all fall within the range of 90 - 110%, and Ai is less than the first threshold, the host computer judges that the flushing step needs to be started; at the same time, the host computer closes the first and second valves and opens the third and fourth valves. Preferably, the value range of the first threshold is 1.8 - 2.

[0095] S3. Real-time monitoring step of the flow rate data in the flushing step, specifically including:

[0096] The inflow rate and outflow rate of the flushing liquid are detected in real time through the third flowmeter located at the flushing liquid inlet and the fourth flowmeter located at the flushing liquid outlet, and the real-time flow data L of the above-mentioned third and fourth flowmeters 3i and L 4i are transmitted to the host computer. The host computer calculates the change rate of passability based on the third flow rate L 3i and the fourth flow rate L 4i , where i is the number of times of real-time acquisition, and i is greater than or equal to 2. When J i-4 , J i-3 , J i-2 , J i-1 , J i all fall within the range of 90% - 110%, calculate .

[0097] S4. Real-time monitoring step of resistance data in the flushing step

[0098] After the flushing step is started, the real-time current of the porous metal inside the filter plate is monitored in real time through the resistance measurement module. The real-time current data I i is sampled for repeated data acquisition at a fixed time interval (such as 0.01s - 0.1s), where i represents the number of acquisitions, and i = 2 - n.

[0099] Among them, when the fusing mechanism in the resistance measurement module is fused, it indicates that there is a large area defect in the silicone rubber elastic medium layer coated on the outside of the porous metal of the filter plate. The host computer directly prompts that the filter life is over and prompts for replacement.

[0100] The host computer calculates the change rate H i of the real-time current data I i obtained by the resistance measurement module = I i - I i-1 / I i . If |H i-4 |, |H i-3 |, |H i-2 |, |H i-1 |, |H i | are all less than 10%, then stop the measurement and calculate C i = I i / I0. This initial current I0 is a device constant that has been measured during the initial equipment assembly and debugging.

[0101] If until the flushing is terminated, the change rate of the real-time current data I i obtained by the resistance measurement module never reaches |H i-4 |, |H i-3 |, |H i-2 |, |H​i-1 |,|H i | are all less than 10%, then the average rate of change of current in the flushing state is determined , where n is the total number of measurements and i represents the i-th measurement.

[0102] S5. terminating the flushing step, specifically comprising:

[0103] When the flushing step reaches the predetermined time, the flushing step is terminated; at the same time, the host computer sends a control signal to the corresponding valve actuator to drive the first and second valves to open and close the third and fourth valves. At this point, the equipment re-enters the filtering working state.

[0104] S6. After the flushing step is terminated, the weight of the solid particles on the filter support plate of the buffer chamber after flushing is measured, and the weight change rate of the solid particles is determined based on historical data.

[0105] The weight G of the solid particles on the filter support plate of the buffer chamber after this flushing is read by the gravity detection module k , where k is the number of flushing times. The host computer will calculate the weight data G after each flushing. k The weight is stored in the storage module to form historical weight data. After the kth flushing, the weight change rate of the solid particles is determined. k -G k-1 | / G k-1 .

[0106] S7. Determine the life of the filter plate, and prompt the host computer through a matching display or prompt device to replace the filter plate.

[0107] The specific detection method of the host computer is as follows:

[0108] When the fuse device of the resistance detection module is blown during the flushing process, it means that the silicone rubber elastic medium layer on the surface of the filter plate is peeled off to a large extent, causing the liquid to contact the porous metal during the flushing process, resulting in a short-circuit current; therefore, when the fuse device is blown during the flushing process, it indicates that the life of the filter plate is exhausted.

[0109] If no fuse is blown, perform the following test:

[0110] when Less than or equal to , it is judged that the filter plate has not reached the end of its life and can continue to be used.

[0111] when Greater than , then further judge the resistance monitoring situation, if it meets 1)C i Between 0.8 and 1.2, or Di between 0.9 and 1.4 and H iare all less than 5; 2) |G k -G k-1 | / G k-1 is less than 15%, it is determined that the life of the filter plate has not been exhausted and can continue to be used. Otherwise, it is prompted that the life of the filter plate of this filter has been exhausted and needs to be replaced.

[0112] The above shows and describes the basic principles, main features and advantages of the present invention. Therefore, the above is only an embodiment of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments. What is described in the above embodiments and the specification is only the principle of the present invention. Without departing from the spirit and scope of the present invention, the present invention also includes various equivalent changes and improvements, and these changes and improvements will all fall within the scope of the present invention claimed. The scope of protection claimed by the present invention is defined by the appended claims and their equivalents.

Claims

1. A detection method for the replacement requirement of an oilfield produced water filter plate, characterized in that, It includes the following steps: S1. Collect data in real time according to the filtering state of the filter plate, and determine the first flow rate L at the water intake inlet 1i and the second flow rate L at the filter outlet 2i ; S2. The first flow rate L obtained according to step S1 1i and the second flow rate L 2i , calculate the change rate Ki and passing ratio Ai of the filter plate, and determine whether to start the flushing step; S3. Determine the third flow rate L3i at the flushing fluid inlet and the fourth flow rate L4i at the flushing fluid outlet according to the real-time monitoring data of the flow rate in the flushing step described in step S2, and calculate the change rate J of the permeability of the flushing fluid i and the passing ratio ; S4. Determine the real-time current I of the metal inside the filter plate according to the real-time monitoring data of the resistance in the flushing step in step S2 i , and calculate the change rate H of the real-time current of the filter plate i , replacement coefficient Ci, and average current change rate Di under the flushing state; S5. When the flushing step reaches the preset duration, end the flushing step, measure the weight Gk of the solid particles on the filter support plate in the buffer chamber after flushing, and judge the change rate E of the solid particle weight according to historical data; S6. Based on what is obtained in step S3 , the change rate Hi of the real-time current of the filter plate obtained in step S4, the replacement coefficient Ci, the average change rate Di of the current under the flushing state, and the change rate E of the solid particle weight obtained in step S5 are used to determine the service life of the filter plate.

2. The detection method according to claim 1, wherein The calculation formula for the change rate Ki of the passability described in step S2 is: ； The calculation formula for the ratio Ai is as follows: ; where i is the number of real-time acquisitions, and i is greater than or equal to 2.

3. The detection method according to claim 2, wherein, The judgment method for whether to start the flushing step described in step S2 is: When K i-4 , K i-3 , K i-2 , K i-1 , K i all fall within the range of 90 - 110%, and when A i is less than the first threshold α, the flushing step is started, otherwise it is not started, where the value of the first threshold α is 1.8 - 2.

4. The detection method according to claim 1, characterized in that, The permeability change rate J of the flushing liquid described in step S3 i is calculated by the formula: ， where i is the number of real-time acquisitions, and i is greater than or equal to 2.

5. The detection method according to claim 4, wherein The calculation method of the ratio described in step S3 is as follows: ​ When Ji-4, Ji-3, Ji-2, Ji-1, and Ji all fall within the range of 90-110%, calculate according to the following formula: 。 6. The detection method according to claim 1, wherein The H described in step S4 i has the following calculation formula: 。 7. The detection method according to claim 6, wherein The C described in step S4 i is calculated as follows: When |H i-4 |, |H i-3 |, |H i-2 |, |H i-1 |, |H i | are all less than 10%, then calculate according to the following formula: C i =I i / I0; where I0 is the initial current, which is a device constant measured during the initial equipment assembly and commissioning.

8. The detection method according to claim 6, characterized in that The calculation method for Di described in step S4 is: If until the flushing terminates, the change rate of the real-time current Ii never reaches the condition that |Hi-4|, |Hi-3|, |Hi-2|, |Hi-1|, and |Hi| are all less than 10%, then calculate according to the following formula: ； where n is the total number of measurements, and i represents the i-th measurement.

9. The detection method according to claim 1, wherein The calculation formula for the change rate E of the solid particle weight described in step S5 is: E = |Gk - Gk-1| / Gk-1; where k is the number of flushing times.

10. The detection method according to claim 1, characterized in that, The method for judging the service life of the filter plate described in step S6 is specifically: When is less than or equal to , it is determined that the life of the filter plate has not been exhausted and can continue to be used; When is greater than , further judge the resistance monitoring situation. where a, n, b, and d are all constant values set according to experience; If any of the following is satisfied, it is judged that the service life of the filter plate has not been exhausted and can continue to be used; otherwise, the service life of the filter plate has been exhausted and needs to be replaced; 1)C i between 0.8 and 1.2, or D i between 0.9 and 1.4 and H i both are less than 5; 2) E is less than 15%.

11. The detection device for the detection method according to any one of claims 1-10, characterized in that, The detection device includes a filter, a flushing water tank, a buffer chamber, a resistance measurement module, a weight measurement module, and a host computer; The extraction liquid inlet of the filter is connected to the host computer through a first valve and a first flowmeter, the filtration outlet of the filter is connected to the host computer through a second valve and a second flowmeter, the flushing liquid inlet of the filter is respectively connected to the host computer and the flushing water tank through a third valve and a third flowmeter, and the flushing liquid outlet of the filter is connected to the host computer and the buffer chamber respectively through a fourth valve and a fourth flowmeter; One end of the resistance measurement module is connected to the filter, and the other end is connected to the host computer; One end of the weight measurement module is connected to the buffer chamber, and the other end is connected to the host computer.

12. The detection device according to claim 11, characterized in that, A filter plate is arranged inside the filter. The filter plate has a skeleton formed by foam metal and an elastic medium layer coated outside the skeleton; there are at least two metal exposed points on the filter plate.

13. The detection device according to claim 12, characterized in that, The resistance measurement module further includes a fusing mechanism. When the fusing mechanism is fused, it indicates that the service life of the filter is complete and needs to be replaced.

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