High-precision wide-range crude oil moisture content measuring device and method

Abstract

The invention provides a high-precision wide-range crude oil moisture content measuring device and method, and belongs to the technical field of petroleum detection. Comprising a metal liquid pipeline provided with a hollow cavity, the two ends of the metal liquid pipeline in the radial direction are connected with a crude oil pipeline in a sealed mode respectively, and the cavity is arranged in a sealed mode through a pipe cap sealing head at one end of the metal liquid pipeline in the axial direction; the sensor connecting string is arranged at the other end of the metal liquid pipeline in the axial direction, is in sealed connection with the metal liquid pipeline and is used for measuring temperature information and capacitance information of the medium in the cavity and outputting the temperature information and the capacitance information to the outside; and the meter head is arranged on one side, far away from the metal liquid pipeline, of the sensor connecting string and is used for acquiring the temperature information and the capacitance information output by the sensor connecting string and measuring the water content through a built-in water content detection algorithm. Based on the device, the real capacitance of the water-containing crude oil medium is obtained by using a dual-frequency measurement method, and then the water content is obtained by using an interpolation method.

Description

Technical Field

[0001] This invention relates to the field of petroleum testing technology, and in particular to a high-precision, wide-range crude oil water content measurement device and method. Background Technology

[0002] Oil water cut refers to the ratio of the volume of associated water in oil to the total volume of the oil-water mixture, and is one of the important parameters for oil extraction, processing, and research. Currently, it is common for crude oil produced from oil wells to be in a high water-cut state due to long-term water injection. Accurate measurement of oil water cut is of great significance for extending oil well life, subsequent chemical processing, and crude oil storage, transportation, and sales. The capacitance method has advantages such as simple structure, fast response, and low cost. Its basic principle is to utilize the significantly different dielectric constants of oil and water, and to deduce the water cut by measuring the equivalent dielectric constant of the oil-water mixture. Modern capacitance methods typically use capacitance-to-digital converter chips for measurement. These chips convert the capacitance value into a digital signal by periodically charging and discharging the probe capacitor and counting the transferred charge.

[0003] However, in practical applications, especially in crude oil with high water content and high salinity, this method has serious limitations. Crude oil with high water and high salinity is no longer an ideal dielectric, but exhibits strong conductivity. This conductivity generates conductive losses. The charge accumulated on the chip leaks through the conductive path, resulting in a reduction in the total transferred charge, leading to an overestimation of the chip's charge measurement and an underestimation of the measured capacitance. This deviation caused by conductive losses results in a significantly lower measurement of water content. Simultaneously, under high water content conditions, the sensitivity of the mixture's dielectric constant to changes in water content decreases drastically, and fluctuations in conductive losses generate significant noise, further reducing measurement stability and resolution. Most methods use an insulating layer between the capacitive sensor and the liquid to eliminate conductive losses; however, insulating layers cannot completely eliminate all conductive leakage, and the problem of conductive losses still exists under high water content conditions even with an insulating layer alone.

[0004] Therefore, it is essential to provide a high-precision, wide-range crude oil water content measurement device and method to overcome the problems of low range, low precision, and low resolution caused by conductivity loss in the traditional capacitance method under high water content conditions. Summary of the Invention

[0005] In view of this, the present invention proposes a high-precision, wide-range crude oil water content measuring device and method suitable for measuring the water content of corrosive water-containing crude oil, providing more accurate measurement results.

[0006] On one hand, the present invention provides a high-precision, wide-range crude oil water content measuring device, comprising: A metal liquid pipeline has a hollow cavity. The two ends of the metal liquid pipeline in the radial direction are respectively sealed and connected to the crude oil pipeline. One end of the metal liquid pipeline in the axial direction is sealed with a pipe cap to seal the cavity. A sensor connection string is set at the other end of the metal liquid pipe in the axial direction and is sealed to the metal liquid pipe. It is used to measure the temperature and capacitance information of the medium in the cavity and output it to the outside. The meter head is located on the side of the sensor connection string away from the metal liquid pipe. It is used to acquire the temperature and capacitance information output by the sensor connection string and measure the moisture content through a built-in moisture content detection algorithm.

[0007] Based on the above technical solutions, preferably, the metal liquid pipeline is a four-way pipe, and all non-cap end of the metal liquid pipeline is provided with a flange, which is sealed to the metal liquid pipeline.

[0008] Preferably, the sensor connection string includes a blind flange assembly, a first sensor probe, and a second sensor probe. The blind flange assembly is sealed to a flange at one end of the axial direction of the metal liquid pipeline. A meter is provided on the side of the blind flange assembly away from the metal liquid pipeline, and the first sensor probe and the second sensor probe are sealed on the side of the blind flange assembly close to the metal liquid pipeline. The first sensor probe and the second sensor probe extend toward the pipe cap. The first sensor probe is used to measure the capacitance information of the medium in the metal liquid pipeline, and the second sensor probe is used to measure the temperature information of the medium in the metal liquid pipeline. The first sensor probe and the second sensor probe are also electrically connected to the meter, and the meter is electrically connected to the processor.

[0009] More preferably, the blind flange assembly includes a blind flange, a union interface assembly, and a blind flange adapter assembly. The blind flange is sealed to a flange plate, and a first through hole is provided at the center of the blind flange. A union interface assembly is provided on the side of the blind flange away from the metal liquid pipeline. The union interface assembly passes through the first through hole and extends into the cavity. The union interface assembly is also connected to the meter head. The blind flange adapter assembly is disposed inside the union interface assembly. An opening is provided at the end of the blind flange adapter assembly near the union interface assembly. A second through hole and a third through hole are provided at the end of the blind flange adapter assembly away from the union interface assembly. The blind flange adapter assembly is sealed to the end of the union interface assembly that extends into the cavity through the opening. The second through hole is used to place a first sensor probe, and the third through hole is used to place a second sensor probe.

[0010] In a further preferred embodiment, a sleeve connector is provided between the first sensor probe and the blind plate adapter assembly. The sleeve connector is disposed through the second through hole and is sealed to the blind plate adapter assembly. A polytetrafluoroethylene insulating layer and a sealing gasket are provided at the end of the sleeve connector near the first sensor probe. The insulating layer is used to improve the corrosion resistance of the first sensor probe and the sleeve connector, and the sealing gasket is used to seal the gap between the first sensor probe and the sleeve connector.

[0011] Preferably, the meter head includes a housing, a main control board, a display screen, and a wireless communication board. The main control board, the wireless communication board, and the battery are disposed inside the housing, and the display screen is disposed on one side of the opening in the housing. The main control board is used to receive temperature information and capacitance information, and to measure the moisture content through a built-in moisture content detection algorithm. The main control board is communicatively connected to the display screen and the wireless communication board. The display screen is used to display the output moisture content and temperature information, and the wireless communication board is used for communication between the main control board and the host computer.

[0012] Based on the above technical solutions, preferably, the meter head measures the water content using a built-in water content detection algorithm. At the current temperature, it solves for the water content of different media using a dual-frequency method. The first sensor probe is excited by a first frequency, and then by a second frequency. Since the first frequency is less than the second frequency, the total admittance obtained from both methods is used to obtain the capacitance value of the water-containing crude oil medium to be tested. The capacitance-temperature slope corresponding to the water and oil media is calculated, and combined with the difference between the current temperature and the calibration temperature, the water content of the medium to be tested is calculated using linear interpolation based on the capacitance values ​​of the water and oil media under the current temperature conditions and the capacitance value of the water-containing crude oil medium to be tested.

[0013] On the other hand, the present invention provides a high-precision, wide-range method for measuring the water content of crude oil, comprising the following steps: S1: The device is configured as described above; S2: Set the high-precision, wide-range crude oil water content measuring device to calibration mode; S3: At the calibration temperature, water is introduced into the cavity of the metal liquid pipe beforehand, and the capacitance value of the water is measured. S4: Remove the water medium from the metal liquid pipeline and instead introduce medium oil into the cavity of the metal liquid pipeline at the calibration temperature, and measure the capacitance value of the medium oil. S5: Connect the metal liquid pipeline to the crude oil medium pipeline, obtain the capacitance and temperature information of the crude oil medium to be tested, and output them to the meter head; S6: Obtain the water content of the crude oil medium to be tested by interpolation.

[0014] Preferably, the capacitance values ​​of the water and oil media are measured by obtaining the capacitance values ​​of pure water and pure oil media at the calibration temperature, respectively.C w0 and C o0 The slopes of the capacitance-temperature curves for pure water and pure oil media were measured at different temperatures. kw and ko The capacitance values ​​of pure water and pure oil media at the current temperature are obtained. C w and C o , C w = C w0 + kw ×△ T , C o = C o0 + ko ×△ T ;△ T It is the difference between the current temperature and the calibrated temperature.

[0015] Preferably, in step S5, the capacitance information of the crude oil medium to be tested is obtained by exciting the first sensor probe with a first frequency and then exciting the first sensor probe with a second frequency. The first frequency is less than the second frequency. The total admittance obtained by combining the two frequencies is used to obtain the capacitance value of the water-containing crude oil medium to be tested as capacitance information.

[0016] The present invention provides a high-precision, wide-range crude oil water content measurement device and method, which, compared with the prior art, has the following advantages: 1. A crude oil water content measuring device is provided, including a measuring chamber, a measuring sensor inserted into the chamber, and a data processing head. The physical structure is suitable for online installation. The measuring sensor is made of corrosion-resistant material and has an additional insulation layer, achieving not only electrical isolation and short-circuit protection but also corrosion resistance, anti-wax deposit prevention, and anti-scaling capabilities. It is particularly suitable for measurements under waxy and high-mineralization conditions, while also reducing gas interference and improving the resolution of dielectric constant changes. The monitor adopts a detachable body and easily disassembled probe structure, with no mechanical rotating parts, which greatly improves the reliability of the equipment and reduces the risk of blockage. Furthermore, in terms of interface and protection, it adopts a standard oil well pipeline flange interface for convenient installation. 2. The water content is measured using the capacitance method. To overcome the problem of reduced measurement accuracy and resolution of the capacitance sensor under high water content conditions, a dual-frequency measurement method is implemented: the probe capacitance is measured twice at two different frequencies within a very short period of time, obtaining two sets of independent count values. Since there is a definite linear relationship between the measured count value and the true capacitance, equivalent conductance, and holding time, the true capacitance and equivalent conductance of the water-containing crude oil medium can be accurately separated at the algorithm level by establishing and solving a mathematical model. Finally, the separated true capacitance value, which is not affected by conductance, is used in conjunction with real-time temperature for table lookup and linear difference compensation to obtain an accurate water content. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a half-section front view of the mechanical structure of the high-precision wide-range crude oil water content measurement device and method of the present invention. Figure 2 This is a perspective view of the high-precision, wide-range crude oil water content measurement device and method of the present invention. Figure 3 The images show a front view, a half-section front view, and a perspective view of the sensor connection string of the high-precision, wide-range crude oil water content measurement device and method of the present invention. Figure 4 This is a schematic diagram of the meter head structure of the high-precision, wide-range crude oil water content measurement device and method of the present invention; Figure 5 This is a schematic diagram of the algorithm flow of the high-precision, wide-range crude oil water content measurement device and method of the present invention.

[0019] Reference numerals: 1. Metal liquid pipeline; 2. Flange; 3. Sensor connection string; 4. Bolt; 5. Nut; 6. Flange gasket; 31. Blind flange assembly; 32. First sensor probe; 33. Second sensor probe; 311. Blind flange; 312. Union interface assembly; 313. Blind flange adapter assembly; 7. Sleeve connector; 8. Insulation layer; 9. Sealing gasket; 10. Sensor connector. Detailed Implementation

[0020] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0021] Traditional capacitance methods suffer from low range, low accuracy, and low resolution due to conductivity losses under high moisture content conditions, affecting measurement precision. Therefore, if... Figure 1 and Figure 2 As shown, in one aspect, the present invention provides a high-precision, wide-range crude oil water content measuring device, comprising: The metal liquid pipeline 1 has a hollow cavity. Both ends of the metal liquid pipeline 1 in the radial direction are respectively sealed and connected to the crude oil pipeline. One end of the metal liquid pipeline 1 in the axial direction is sealed with a pipe cap. The pipe cap is hemispherical.

[0022] Sensor connection string 3 is set at the other end of the metal liquid pipe 1 in the axial direction and is sealed to the metal liquid pipe 1. It is used to measure the temperature and capacitance information of the medium in the cavity and output it to the outside. The meter head is located on the side of the sensor connection string 3 away from the metal liquid pipe 1, and is used to acquire the temperature and capacitance information output by the sensor connection string 3, and measure the moisture content through the built-in moisture content detection algorithm.

[0023] Specifically, such as Figure 1 and Figure 2 As shown, the metal liquid pipeline 1 is a four-way pipe. All non-capped ends of the metal liquid pipeline 1 are equipped with flanges 2, which are sealed to the metal liquid pipeline 1. The medium to be measured flows radially through the metal liquid pipeline 1, and the sensor connection string 3, arranged axially, acquires the temperature and capacitance information of the medium. For example... Figure 1 As shown, flange 2 is located at one end of the metal liquid pipeline 1 in both the radial and axial directions, and is sealed to the metal liquid pipeline 1 by welding. Sensor connection string 3 is located on flange 2 at one end of the axial extension direction of the cavity of the metal liquid pipeline 1, and is fastened by bolts 4 and nuts 5. Flange gaskets 6 are used to seal between flange 2 and sensor connection string 3, and between flange 2 and adjacent pipelines, to prevent media leakage.

[0024] like Figure 3As shown, the sensor connection string 3 includes a blind flange assembly 31, a first sensor probe 32, and a second sensor probe 33. The blind flange assembly 31 is sealed to a flange 2 at one end of the metal liquid pipeline 1 in the axial direction. A meter is provided on the side of the blind flange assembly 31 away from the metal liquid pipeline 1, and the first sensor probe 32 and the second sensor probe 33 are sealed on the side of the blind flange assembly 31 close to the metal liquid pipeline 1. The first sensor probe 32 and the second sensor probe 33 extend toward the pipe cap end. The first sensor probe 32 is used to measure the capacitance information of the medium in the metal liquid pipeline 1, and the second sensor probe 33 is used to measure the temperature information of the medium in the metal liquid pipeline 1. The first sensor probe 32 and the second sensor probe 33 are also electrically connected to the meter, and the meter is electrically connected to the processor.

[0025] Specifically, in combination Figure 2 As shown, the blind flange assembly 31 includes a blind flange 311, a union interface assembly 312, and a blind flange adapter assembly 313. The blind flange 311 is sealed to the flange 2. A first through hole is provided at the center of the blind flange 311. A union interface assembly 312 is provided on the side of the blind flange 311 away from the metal liquid pipeline 1. The union interface assembly 312 passes through the first through hole and extends into the cavity. The union interface assembly 312 is also connected to the meter head. The blind flange adapter assembly 313 is disposed inside the union interface assembly 312. An opening is provided at the end of the blind flange adapter assembly 313 near the union interface assembly 312. A second through hole and a third through hole are provided at the end of the blind flange adapter assembly 313 away from the union interface assembly 312. The blind flange adapter assembly 313 is connected to one end of the union interface assembly 312 through the opening. The second through hole is used to place the first sensor probe 32, and the third through hole is used to place the second sensor probe 33.

[0026] In one embodiment, the blind plate adapter assembly 313 has a stepped appearance and a cylindrical internal structure. The union interface assembly 312 has a cylindrical structure that is larger at the top and smaller at the bottom, and both ends are provided with external threads. One end of the union interface assembly 312 is threadedly connected to the open end of the blind plate adapter assembly 313, and the other end of the union interface assembly 312 is threadedly connected to the meter head.

[0027] Between the first sensor probe 32 and the blind plate adapter assembly 313, a sleeve connector 7 and a sensor connector 10 are sequentially arranged. One end of the sleeve connector 7 is threadedly connected to one end of the sensor connector 10 through a threaded interface. The other end of the sensor connector 10 is disposed through the second through hole and is sealed to the blind plate adapter assembly 313. The first sensor probe 32 is sealed to the other end of the sleeve connector 7. The sensor connector 10 includes an insulating layer 8 made of polytetrafluoroethylene insulating material and a sealing gasket 9. The insulating layer 8 is used to increase the anti-wax and anti-corrosion performance between the sleeve connector and the sensor connector 10. The sealing gasket 9 is used to seal the gap between the sleeve connector 77 and the sensor connector 10.

[0028] The first sensor probe 32 and the second sensor probe 33 are cylindrical, but with different diameters and lengths. Therefore, they are correspondingly embedded in the second and third through holes of different diameters. One end of the housing of the first sensor probe 32 is in direct contact with the liquid to read the capacitance information of the medium, while the other end is threadedly connected to the blind plate adapter assembly 313 via the sleeve connector 7 and the sensor connector 10. The second sensor probe 33 acquires the temperature information of the medium.

[0029] like Figure 4 As shown, the meter head includes a housing, a main control board, a display screen, and a wireless communication board. The main control board, the wireless communication board, and the battery are housed inside the housing, and the display screen is located on one side of the housing opening. The main control board is used to receive temperature and capacitance information and measure the moisture content using a built-in moisture content detection algorithm. The main control board is connected to the display screen and the wireless communication board for communication. The display screen is used to show the output moisture content and temperature information, and the wireless communication board is used for communication between the main control board and the host computer. Figure 4 The structure of the shell is shown.

[0030] In this embodiment, the principle of obtaining the water content of the tested water-containing crude oil medium by measuring the capacitance of the medium is as follows: The main control board obtains capacitance information by indirectly counting during charging and discharging, using a constant voltage. V exc Give the capacitor to be tested C x Charge for a period of time T ch Then the capacitor C x The charge obtained from charging Q cyc Transfer to a larger integrating capacitor C int Repeat the above process until the integrating capacitor... C int The voltage on the plate reaches the preset threshold. V thThe charge transferred in one measurement cycle is approximately: , of which R on Switch on resistance, T hold To keep time, C stray Parasitic capacitance, C int,par Parasitic capacitances in parallel with integrating capacitors, Q inj Injecting charge into the switch, G x For dielectric equivalent conductivity, G dc For the equivalent conductance of the capacitance measurement circuit, when Q inj , T ch and T hold When I was very young, Q cyc and C x Approximately proportional.

[0031] To reach the points threshold, the required number of charging cycles is: , V 0 represents the integrating capacitor. C int The starting voltage. From the above formula, it can be seen that the number of cycles is inversely proportional to the capacitance value of the water-containing crude oil medium being tested. By comparing the capacitance coefficients in pure water and pure oil media... α i , β i and N i After calibration, the apparent capacitance can be obtained. .

[0032] If the liquid being tested is an insulator, then the dielectric equivalent conductivity is... G x =0, then during the holding phase, the capacitance C x The charge is not lost. However, under conditions of high water and high salinity, the electrical conductivity of the liquid becomes increasingly important. C x ≠0. At this time C x The charge will be lost through the liquid. Due to the charging time... T ch and holding time T hold They are all very small, yes Q cycBy linearly approximating the formula, we can obtain the following formula: ,in , D = AT hold The constant term affecting leakage current, B = Q inj To fix the offset error. According to the above formula, the charge generated in each cycle will not only vary with the capacitance... C x It increases linearly, and also with the equivalent conductivity of the medium. G x It decreases linearly.

[0033] During calibration, the instrument is typically calibrated using a standard liquid with a known dielectric constant, at which point the instrument establishes a set number of charging cycles. N With capacitor C x The mapping relationship, in actual measurement, is the equivalent conductivity of the medium. G x >0, the transferred charge decreases, and the count value... N The number of charging cycles is too high; the instrument still uses the number established during calibration. N With capacitor C x The mapping relationship, a larger count value N This is incorrectly interpreted as a smaller capacitance value, resulting in an apparent capacitance of... Expressing the capacitor in complex admittance form, the equivalent admittance of the entire circuit is: , j The imaginary unit, ω Let be the angular frequency. Simultaneously, in the physical sense of the dielectric, using the complex permittivity, the circuit model is expressed by the following equation: The first term on the right side of the equation represents the real part of the complex permittivity, and the second term represents the imaginary part. The imaginary part is mainly determined by the conduction loss and polarization loss. In low-frequency measurements, the conduction loss is much greater than the polarization loss. ε₀ is the vacuum permittivity, and σ is the conductivity. The loss factor is defined. Therefore, in the physical sense of the medium, the loss factor can also be expressed as At this point, the deviation formula can be expressed as: According to geometric deconvolution, capacitance C x Dielectric constant of the water-containing crude oil medium to be tested Proportional , It is a constant related to the geometry of the first detector probe.

[0034] The water content φ can be obtained by inverse solving the Lichtenecker equation. ,in Let be the real part of the complex permittivity of water; when conductivity loss dominates, the measured moisture content deviation... .

[0035] As can be seen from the curve of the Lichtenecker formula, the curve becomes very flat when the moisture content is high. This means that even if the moisture content φ changes significantly, The change is small, and the resolution decreases accordingly. Meanwhile, under high water content conditions, the aqueous phase may become a continuous term, causing changes in conductivity and even the dielectric equivalent conductivity. G x The fluctuations are severe, and the measurement results are extremely unstable. Even after multiple measurements to compensate for the equivalent conductivity of the medium, the results remain inconsistent. G x However, its random fluctuations still generate noise. Meanwhile, capacitance in high water content environments... C x The change is relatively weak, while the change in conductivity noise corresponds to the dielectric equivalent conductivity. G x The signal-to-noise ratio is low, making it difficult to improve the resolution.

[0036] Therefore, this invention employs a dual-frequency method to determine the water content. The dielectric and conductivity effects of liquids exhibit different response behaviors in an alternating electric field. Dielectric effect... Directly related to frequency, while conductivity effect G x The term is basically unrelated to frequency.

[0037] The meter measures the water content using a built-in water content detection algorithm. At the current temperature, it uses a dual-frequency method to determine the water content of different media. The first sensor probe 32 is excited by a first frequency, and then by a second frequency. Since the first frequency is less than the second frequency, the total admittance obtained from both methods is used to obtain the capacitance value of the water-containing crude oil medium being tested. The capacitance-temperature slope corresponding to the water and oil media is calculated, and combined with the difference between the current temperature and the calibration temperature, the water content of the medium being tested is calculated using linear interpolation based on the capacitance values ​​of the water and oil media under the current temperature conditions and the capacitance value of the water-containing crude oil medium being tested.

[0038] During the first measurement, the instrument uses a low frequency ω1 to excite the first sensor probe 32, at which time the total admittance obtained by the first sensor probe 32 is: Then, a higher frequency ω2 excites the first sensor probe 32, at which point the total admittance measured by the instrument is... The actual capacitance after compensation can be obtained by solving the problem.C x , and dielectric equivalent conductivity This invention uses a temperature correction method to reduce the impact of changes in conductivity on capacitance. The conductivity σ of the dielectric is highly sensitive to temperature changes, which can affect the equivalent conductivity of the dielectric. G x The change in the equivalent conductivity of the medium as the temperature rises. G x This often increases accordingly, leading to an increase in apparent capacitance. The present invention measures the temperature of a liquid using a temperature sensor, which is essentially a thermistor. The sensor determines the liquid temperature by reading the resistance value of the thermistor. The capacitance readings of two key points, pure oil and pure water, will drift linearly with temperature changes. The present invention compensates for this drift by pre-measuring this drift rate during calibration and dynamically adjusting these two points according to the real-time temperature during operation.

[0039] like Figure 5 As shown, on the other hand, the present invention provides a high-precision, wide-range method for measuring the water content of crude oil, comprising the following steps: S1: The device is configured as described above; S2: Set the high-precision, wide-range crude oil water content measuring device to calibration mode; S3: At the calibration temperature, water medium is introduced into the cavity of the metal liquid pipe 1 beforehand, and the capacitance value of the water medium is measured. S4: Remove the medium water from the metal liquid pipeline 1, and instead introduce medium oil into the cavity of the metal liquid pipeline 1 at the calibration temperature, and measure the capacitance value of the medium oil. The capacitance values ​​of the water and oil media mentioned in steps S3 and S4 are obtained by acquiring the capacitance values ​​of pure water and pure oil media at the calibration temperature, respectively. C w0 and C o0 The slopes of the capacitance-temperature curves for pure water and pure oil media were measured at different temperatures. kw and ko The capacitance values ​​of pure water and pure oil media at the current temperature are obtained. C w and C o , C w = C w0 + kw ×△ T , C o = Co0 + ko ×△ T ;△ T It is the difference between the current temperature and the calibrated temperature.

[0040] S5: Connect the metal liquid pipeline 1 to the crude oil medium pipeline, obtain the capacitance and temperature information of the crude oil medium to be tested, and output them to the meter head; In step S5, the capacitance information of the crude oil medium to be tested is obtained by exciting the first sensor probe 32 with a first frequency and then exciting the first sensor probe 32 with a second frequency. The first frequency is less than the second frequency. The total admittance obtained by combining the two frequencies is used to obtain the capacitance value of the water-containing crude oil medium to be tested as capacitance information.

[0041] S6: Obtain the water content of the crude oil medium to be tested by interpolation.

[0042] Calculate moisture content using linear interpolation at the new endpoint: .

[0043] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A high-precision, wide-range crude oil water content measuring device, characterized in that, include: A metal liquid pipeline has a hollow cavity. The two ends of the metal liquid pipeline in the radial direction are respectively sealed and connected to the crude oil pipeline. One end of the metal liquid pipeline in the axial direction is sealed with a pipe cap to seal the cavity. A sensor connection string is set at the other end of the metal liquid pipe in the axial direction and is sealed to the metal liquid pipe. It is used to measure the temperature and capacitance information of the medium in the cavity and output it to the outside. The meter head is located on the side of the sensor connection string away from the metal liquid pipe. It is used to acquire the temperature and capacitance information output by the sensor connection string and measure the moisture content through a built-in moisture content detection algorithm.

2. The high-precision, wide-range crude oil water content measuring device according to claim 1, characterized in that, The metal liquid pipeline is a four-way pipe, and all non-capped ends of the metal liquid pipeline are equipped with flanges, which are sealed to the metal liquid pipeline.

3. The high-precision, wide-range crude oil water content measuring device according to claim 2, characterized in that, The sensor connection string includes a blind flange assembly, a first sensor probe, and a second sensor probe. The blind flange assembly is sealed to a flange at one end of the axial direction of the metal liquid pipeline. A meter is provided on the side of the blind flange assembly away from the metal liquid pipeline, and the first sensor probe and the second sensor probe are sealed on the side of the blind flange assembly close to the metal liquid pipeline. The first sensor probe and the second sensor probe extend towards the pipe cap. The first sensor probe is used to measure the capacitance information of the medium in the metal liquid pipeline, and the second sensor probe is used to measure the temperature information of the medium in the metal liquid pipeline. The first sensor probe and the second sensor probe are also electrically connected to the meter, and the meter is electrically connected to the processor.

4. The high-precision, wide-range crude oil water content measuring device according to claim 3, characterized in that, The blind flange assembly includes a blind flange, a union interface assembly, and a blind flange adapter assembly. The blind flange is sealed to a flange plate. A first through hole is provided at the center of the blind flange. A union interface assembly is provided on the side of the blind flange away from the metal liquid pipeline. The union interface assembly passes through the first through hole and extends into the cavity. The union interface assembly is also connected to the meter head. The blind flange adapter assembly is located inside the union interface assembly. An opening is provided at the end of the blind flange adapter assembly near the union interface assembly. A second through hole and a third through hole are provided at the end of the blind flange adapter assembly away from the union interface assembly. The blind flange adapter assembly is sealed to the end of the union interface assembly that extends into the cavity through the opening. The second through hole is used to place a first sensor probe, and the third through hole is used to place a second sensor probe.

5. The high-precision, wide-range crude oil water content measuring device according to claim 4, characterized in that, A sleeve connector is also provided between the first sensor probe and the blind plate adapter assembly. The sleeve connector is installed through the second through hole and is sealed to the blind plate adapter assembly. A polytetrafluoroethylene insulation layer and a sealing gasket are provided at the end of the sleeve connector near the first sensor probe. The insulation layer is used to improve the corrosion resistance of the first sensor probe and the sleeve connector, and the sealing gasket is used to seal the gap between the first sensor probe and the sleeve connector.

6. The high-precision, wide-range crude oil water content measuring device according to claim 3, characterized in that, The meter head includes a housing, a main control board, a display screen, and a wireless communication board. The main control board, the wireless communication board, and the battery are housed inside the housing, and the display screen is located on one side of the housing opening. The main control board is used to receive temperature and capacitance information and measure the moisture content using a built-in moisture content detection algorithm. The main control board is communicatively connected to the display screen and the wireless communication board. The display screen is used to display the output moisture content and temperature information, and the wireless communication board is used for communication between the main control board and the host computer.

7. The high-precision, wide-range crude oil water content measuring device according to claim 1, characterized in that, The meter measures the water content using a built-in water content detection algorithm. At the current temperature, it solves the water content of different media using a dual-frequency method. The first sensor probe is excited by the first frequency, and then the first sensor probe is excited by the second frequency. The first frequency is less than the second frequency. The total admittance obtained by combining the two is used to obtain the capacitance value of the water-containing crude oil medium to be tested. The capacitance-temperature slopes corresponding to the medium water and medium oil are calculated. Combined with the difference between the current temperature and the calibration temperature, the water content of the medium to be tested is calculated by linear interpolation based on the capacitance values ​​of the medium water and medium oil under the current temperature conditions and the capacitance value of the water-containing crude oil medium to be tested.

8. A high-precision, wide-range method for measuring the water content of crude oil, characterized in that, Includes the following steps: S1: Configure the apparatus as described in any one of claims 3-7; S2: Set the high-precision, wide-range crude oil water content measuring device to calibration mode; S3: At the calibration temperature, water is introduced into the cavity of the metal liquid pipe beforehand, and the capacitance value of the water is measured. S4: Remove the water medium from the metal liquid pipeline and instead introduce medium oil into the cavity of the metal liquid pipeline at the calibration temperature, and measure the capacitance value of the medium oil. S5: Connect the metal liquid pipeline to the crude oil medium pipeline, obtain the capacitance and temperature information of the crude oil medium to be tested, and output them to the meter head; S6: Obtain the water content of the crude oil medium to be tested by interpolation.

9. The method for measuring crude oil water content with high precision and wide measurement range according to claim 8, characterized in that, The capacitance values ​​of water and oil are measured by obtaining the capacitance values ​​of pure water and pure oil at the calibration temperature, respectively. C w0 and C o0 The slopes of the capacitance-temperature curves for pure water and pure oil media were measured at different temperatures. kw and ko The capacitance values ​​of pure water and pure oil media at the current temperature are obtained. C w and C o , C w = C w0 + kw ×△ T , C o = C o0 + ko ×△ T ;△ T It is the difference between the current temperature and the calibrated temperature.

10. A high-precision, wide-range crude oil water content measurement method according to claim 8, characterized in that, In step S5, the capacitance information of the crude oil medium to be tested is obtained by exciting the first sensor probe with a first frequency and then exciting the first sensor probe with a second frequency. The first frequency is less than the second frequency. The total admittance obtained by combining the two frequencies is used to obtain the capacitance value of the water-containing crude oil medium to be tested as capacitance information.

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