A crude oil freezing point detection method, device and equipment

Abstract

The application provides a crude oil condensation point detection method, device and equipment, and relates to the technical field of crude oil physical property analysis, to solve the problem of low detection precision of the crude oil condensation point. The crude oil condensation point detection method comprises the following steps: in response to a displacement disturbance excitation applied to the crude oil to be measured, acquiring movement data of a float placed in the crude oil to be measured and temperature data of the crude oil to be measured; determining an oil product rheological state characteristic parameter of the crude oil to be measured according to a dynamic response relationship between the movement data and excitation parameters of the displacement disturbance excitation; and determining the condensation point of the crude oil to be measured according to a change trend of the oil product rheological state characteristic parameter with the temperature data.

Description

Technical Field

[0001] This application relates to the field of crude oil physical property analysis technology, and in particular to a method, apparatus and equipment for detecting the pour point of crude oil. Background Technology

[0002] The pour point of crude oil is a key indicator for measuring the low-temperature fluidity of crude oil. Accurate detection of the pour point of crude oil is of great significance for the selection of crude oil extraction, transportation, storage and processing technologies.

[0003] Existing methods for determining the pour point of crude oil are mainly divided into traditional manual methods and automated methods. Traditional manual methods (such as the test tube tilting method) determine the pour point by visually observing whether the crude oil flows, which suffers from high subjectivity, long testing cycles, and the inability to achieve real-time online testing. Automated methods (such as ultrasonic testing and viscosity testing) achieve a certain degree of automation, but are easily affected by factors such as the water content and impurities of crude oil, which can affect the accuracy of the test. Furthermore, some methods require significant disturbance to the oil during the testing process, which can easily damage the internal wax crystal network structure of the crude oil, causing the test results to deviate from the pour point of the crude oil in its true static state.

[0004] Therefore, how to provide an objective and accurate method for detecting the pour point of crude oil is a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0005] This disclosure provides a method, apparatus, and equipment for detecting the pour point of crude oil, in order to solve the problem of low accuracy in detecting the pour point of crude oil.

[0006] To achieve the above objectives, this application adopts the following technical solution: In a first aspect, a method for detecting the pour point of crude oil is provided, comprising: in response to a displacement disturbance excitation applied to the crude oil to be tested, acquiring motion data of a float placed in the crude oil to be tested and temperature data of the crude oil to be tested; determining the rheological state characteristic parameters of the crude oil to be tested based on the dynamic response relationship between the motion data and the excitation parameters of the displacement disturbance excitation; and determining the pour point of the crude oil to be tested based on the changing trend of the rheological state characteristic parameters with the temperature data.

[0007] As can be seen from the above, the embodiments of this application replace manual visual observation with the motion data of the float and use quantitative data as the basis for judgment, which can eliminate the interference of human factors on the detection results and improve the objectivity and consistency of the detection results.

[0008] Secondly, the embodiments of this application determine the rheological state characteristic parameters of oil based on the dynamic response relationship between motion data and excitation parameters. This response relationship reflects the motion characteristics of the float in crude oil, and is independent of the water content, impurities and other component parameters of crude oil. It has strong anti-interference ability and improves detection accuracy.

[0009] In some embodiments, the displacement disturbance excitation is applied after pausing the cooling process for each preset temperature step of the crude oil under test, and while the crude oil under test is in a constant temperature state; the displacement disturbance excitation includes at least one of the following: sinusoidal displacement disturbance excitation, step displacement disturbance excitation, and pulse displacement disturbance excitation.

[0010] In some embodiments, the motion data includes: acceleration data; the rheological state characteristic parameters of the oil product include relative motion amplitude; the relative motion amplitude is used to characterize the fluidity of the crude oil to be tested; based on the dynamic response relationship between the motion data and the excitation parameters of the displacement disturbance excitation, the characteristic parameters reflecting the rheological state of the crude oil to be tested are determined, including: performing integral transformation processing on the acceleration data to obtain the float displacement time series; determining the excitation displacement time series based on the excitation parameters of the displacement disturbance excitation; and determining the amplitude or root mean square value between the float displacement time series and the excitation displacement time series as the relative motion amplitude.

[0011] In some embodiments, determining the pour point of the crude oil to be tested based on the changing trend of the rheological state characteristic parameters of the oil with temperature data includes: determining the temperature data corresponding to the first time the relative motion amplitude is less than a preset amplitude threshold as the temperature data decreases, based on the changing trend of the relative motion amplitude with temperature data, as the pour point of the crude oil to be tested.

[0012] In some embodiments, the motion data includes: a motion response signal generated in response to displacement disturbance excitation; oil rheological state characteristic parameters including a phase hysteresis angle; the phase hysteresis angle is used to characterize the viscoelasticity of the crude oil to be tested; and the characteristic parameters reflecting the oil rheological state of the crude oil to be tested are determined according to the dynamic response relationship between the motion data and the excitation parameters of the displacement disturbance excitation, including: acquiring the excitation signal of the displacement disturbance excitation; determining the hysteresis phase of the motion response signal relative to the excitation signal according to the correlation characteristics of the motion response signal and the excitation signal, and determining the hysteresis phase as the phase hysteresis angle.

[0013] In some embodiments, determining the pour point of the crude oil to be tested based on the changing trend of the rheological state characteristic parameters of the oil with temperature data includes: determining the temperature data corresponding to the first time the phase lag angle is less than a preset angle threshold as the temperature data decreases, based on the changing trend of the phase lag angle with temperature data, as the pour point of the crude oil to be tested.

[0014] In some embodiments, the motion data includes: acceleration data; characteristic parameters of the oil rheological state include harmonic distortion rate; the harmonic distortion rate is used to characterize the degree of nonlinear response during the formation of the wax crystal network structure inside the crude oil under test; based on the dynamic response relationship between the motion data and the excitation parameters of the displacement disturbance excitation, characteristic parameters reflecting the oil rheological state of the crude oil under test are determined, including: performing frequency domain transformation on the acceleration data to obtain the spectrum distribution; determining the fundamental frequency power and each harmonic power corresponding to the excitation frequency based on the spectrum distribution; and determining the harmonic distortion rate based on the ratio of the fundamental frequency power to each harmonic power.

[0015] In some embodiments, determining the pour point of the crude oil to be tested based on the changing trend of the rheological state characteristic parameters of the oil with temperature data includes: determining the temperature data corresponding to the first time the harmonic distortion rate exceeds a preset distortion rate threshold as the pour point of the crude oil to be tested based on the changing trend of the harmonic distortion rate with temperature data.

[0016] In some embodiments, the motion data includes: acceleration data; the characteristic parameters of the oil rheological state include the residual displacement ratio; the residual displacement ratio is used to characterize the solid properties of the crude oil under test after being excited by a step displacement disturbance; based on the dynamic response relationship between the motion data and the excitation parameters of the displacement disturbance, the characteristic parameters reflecting the rheological state of the crude oil under test are determined, including: performing integral transformation processing on the acceleration data to obtain the float displacement time series; determining the peak displacement and stable residual displacement of the float after being excited by a step displacement disturbance based on the float displacement time series; and determining the ratio of the stable residual displacement to the peak displacement as the residual displacement ratio.

[0017] In some embodiments, determining the pour point of the crude oil to be tested based on the changing trend of the rheological state characteristic parameters of the oil with temperature data includes: determining the temperature data corresponding to the first time the residual displacement ratio exceeds a preset residual displacement ratio threshold as the pour point of the crude oil to be tested based on the changing trend of the residual displacement ratio with temperature data.

[0018] Secondly, a crude oil pour point detection device is provided, comprising: a communication unit and a processing unit; the communication unit is used to acquire motion data of a float placed in the crude oil and temperature data of the crude oil in response to a displacement disturbance excitation applied to the crude oil to be tested; the processing unit is used to determine the rheological state characteristic parameters of the crude oil to be tested based on the dynamic response relationship between the motion data and the excitation parameters of the displacement disturbance excitation; the processing unit is also used to determine the pour point of the crude oil to be tested based on the changing trend of the rheological state characteristic parameters with temperature data.

[0019] Thirdly, a crude oil pour point detection device is provided, including a memory and a processor; the memory is used to store computer execution instructions, and the processor is connected to the memory via a bus; when the crude oil pour point detection device is running, the processor executes the computer execution instructions stored in the memory, so that the crude oil pour point detection device performs the crude oil pour point detection method of the first aspect.

[0020] The crude oil pour point detection device can be an electronic device or a component of an electronic device, such as a chip system within an electronic device. The chip system supports the electronic device in performing the functions involved in the first aspect and any of its possible implementations, such as acquiring and determining the data and / or information involved in the aforementioned crude oil pour point detection method. The chip system includes a chip and may also include other discrete devices or circuit structures.

[0021] Fourthly, a computer-readable storage medium is provided, comprising computer-executable instructions that, when executed on a computer, cause the computer to perform the crude oil pour point detection method described in the first aspect.

[0022] Fifthly, a computer program product is provided, comprising a computer program or instructions that, when executed on a crude oil pour point detection device, cause the crude oil pour point detection device to perform the crude oil pour point detection method as described in the first aspect above.

[0023] It should be noted that the aforementioned computer instructions may be stored, in whole or in part, on a computer-readable storage medium. This computer-readable storage medium may be packaged together with the processor of the crude oil pour point detection device, or it may be packaged separately from the processor of the crude oil pour point detection device; this application does not limit this.

[0024] The descriptions of the second, third, fourth, and fifth aspects of this application can be referenced to the detailed description of the first aspect.

[0025] In the embodiments of this application, the name of the crude oil pour point detection device does not limit the equipment or functional module itself. In actual implementation, these devices or functional modules may appear under other names. For example, the receiving unit may also be called a receiving module, receiver, etc. As long as the function of each device or functional module is similar to that of this application, it falls within the scope of the claims of this application and its equivalents. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the structure of a crude oil pour point detection system provided in an embodiment of this application; Figure 2 A schematic flowchart of a crude oil pour point detection method provided in this application embodiment; Figure 3 This is a schematic diagram of the structure of a crude oil pour point detection device provided in an embodiment of this application; Figure 4 This is a schematic diagram of the hardware structure of a crude oil pour point detection device provided in an embodiment of this application. Detailed Implementation

[0027] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0028] It should be noted that in the embodiments of this application, the words "exemplary" or "for example" are used to indicate examples, illustrations, or explanations. Any embodiment or design scheme described as "exemplary" or "for example" in the embodiments of this application should not be construed as being more preferred or advantageous than other embodiments or design schemes. Specifically, the use of the words "exemplary" or "for example" is intended to present the relevant concepts in a specific manner.

[0029] To facilitate a clear description of the technical solutions of the embodiments of this application, the terms "first" and "second" are used in the embodiments of this application to distinguish the same or similar items with essentially the same function and effect. Those skilled in the art can understand that the terms "first" and "second" are not intended to limit the quantity or execution order.

[0030] As described in the background section, the pour point of crude oil is a key indicator for measuring the low-temperature fluidity of crude oil. It directly determines the selection of crude oil extraction, transportation, storage and processing technologies. Accurate detection of the pour point of crude oil is of great significance for ensuring the safety of crude oil production, reducing transportation energy consumption and avoiding pipeline accidents.

[0031] Currently, crude oil pour point testing is typically conducted in laboratories or industrial sites, and the basic procedure is as follows: Before testing, a crude oil sample is first obtained and placed in a dedicated testing container. The container is equipped with a temperature detection device to monitor changes in the oil temperature in real time.

[0032] During the testing process, the crude oil sample is cooled at a uniform rate using a temperature control device, gradually reducing the oil temperature. Throughout this cooling process, testing personnel or automated equipment need to continuously observe or monitor changes in the crude oil's flow state. When the crude oil temperature drops to a certain critical point, the oil begins to lose its macroscopic fluidity; this critical temperature is the pour point.

[0033] Traditional manual testing methods require operators to periodically tilt the test tube during the cooling process and visually observe whether the liquid surface moves to determine if the crude oil is flowing, thus identifying the pour point. Automated testing methods, on the other hand, use sensors (such as ultrasonic sensors and viscometers) to collect physical parameters reflecting the oil's flow state. When these parameters reach a preset threshold, the temperature point is automatically determined as the pour point.

[0034] However, existing methods for detecting the pour point of crude oil still have many shortcomings in practical applications. Traditional manual testing methods (such as the test tube tilting method and visual observation method) are cumbersome to operate, requiring manual control of the crude oil cooling rate and visual observation of whether the crude oil flows to determine the pour point. The test results are greatly affected by the operator's experience, are highly subjective, have long testing cycles, and have large testing errors. Furthermore, they cannot achieve real-time online testing and are difficult to adapt to the testing needs of industrial sites.

[0035] While automated testing methods (such as ultrasonic testing, dielectric testing, and viscosity testing) have achieved a certain degree of automation, they still have significant drawbacks. Ultrasonic and optical testing methods are easily affected by factors such as crude oil water content, impurities, and air bubbles, which can compromise their accuracy. Viscosity testing relies on complex testing logic and data processing, and the viscosity change is not significant when crude oil is near its pour point, making misjudgments likely. Furthermore, some existing automated testing methods require significant disturbance to the oil during the testing process, which can easily disrupt the internal wax crystal network structure of the crude oil, causing the test results to deviate from the pour point of the crude oil under true static conditions.

[0036] Currently, most float-related detection methods are used for liquid level detection. There is no technical solution that combines floats with inertial detection for crude oil pour point detection. It is impossible to accurately capture changes in crude oil fluidity through the movement of the float, let alone achieve accurate detection of crude oil pour point.

[0037] In other words, current crude oil pour point detection methods have low detection accuracy and weak anti-interference ability. Existing automated detection methods are easily affected by factors such as crude oil composition, impurities, and water content, and cannot accurately capture the sudden change in fluidity before and after the crude oil pour point, which easily leads to misjudgment and missed judgment.

[0038] Secondly, current methods for detecting the pour point of crude oil are complex to operate and costly to implement. Some automated detection methods require complex detection logic and data processing procedures, which place high demands on operation and data processing, making them difficult to widely promote in industrial settings.

[0039] Furthermore, current methods for detecting the pour point of crude oil cannot achieve real-time online detection. Traditional manual detection methods cannot monitor in real time, and some existing automated detection methods require sampling for testing, which cannot achieve in-situ, continuous detection of crude oil. They have poor detection timeliness, are easily blocked by wax, require a large amount of maintenance in the later stages, and lack simple and efficient means of judging fluidity. They cannot accurately determine whether crude oil has lost fluidity and thus determine the pour point through simple detection logic and steps.

[0040] To address the aforementioned issues, this application provides a method for detecting the pour point of crude oil. This method responds to a displacement disturbance applied to the crude oil under test, acquiring motion data of a float placed within the crude oil and temperature data of the crude oil. Based on the dynamic response relationship between the motion data and the excitation parameters of the displacement disturbance, the method determines the rheological state characteristic parameters of the crude oil. Subsequently, the pour point of the crude oil is determined based on the changing trend of the rheological state characteristic parameters with temperature data.

[0041] As can be seen from the above, the embodiments of this application replace manual visual observation with the motion data of the float and use quantitative data as the basis for judgment, which can eliminate the interference of human factors on the detection results and improve the objectivity and consistency of the detection results.

[0042] Secondly, the embodiments of this application determine the rheological state characteristic parameters of oil based on the dynamic response relationship between motion data and excitation parameters. This response relationship reflects the motion characteristics of the float in crude oil, and is independent of the water content, impurities and other component parameters of crude oil. It has strong anti-interference ability and improves detection accuracy.

[0043] The implementation environment for the above-mentioned crude oil pour point detection method can be the crude oil pour point detection system provided in the embodiments of this application.

[0044] Figure 1 This is a schematic diagram of a crude oil pour point detection system provided in an embodiment of this application. Figure 1 As shown, the crude oil pour point detection system includes: a crude oil pour point detection device 101 and a float 102. The float 102 is placed in a container 103 containing the crude oil to be tested.

[0045] The float 102 is equipped with a communication unit for communication with the crude oil pour point detection device 101.

[0046] In some embodiments, the float 102 is further provided with a temperature sensor and an inertial detection unit. The temperature sensor is used to collect temperature data of the crude oil to be tested, and the inertial detection unit is used to collect motion data of the float.

[0047] The float 102 can send the temperature data and motion data it has collected to the crude oil pour point detection device 101, so that the crude oil pour point detection device 101 can execute the crude oil pour point detection method provided in the embodiments of this application based on the received temperature data and motion data.

[0048] In some embodiments, the crude oil pour point detection system provided in this application further includes an excitation device 104. The excitation device 104 is used to apply displacement disturbance excitation to the crude oil to be tested, so that the crude oil pour point detection device 101 acquires temperature data and motion data under displacement disturbance excitation.

[0049] Based on the above system structure, the crude oil pour point detection method provided in the embodiments of this application will be described in detail below.

[0050] The basic principle of this application embodiment is: during the cooling process of the crude oil to be tested, a controllable slight excitation is applied to the crude oil to be tested, and the motion response of the float is captured by the inertial detection unit built into the float. Based on the change in the dynamic relationship between the float response and the excitation, the transition of the crude oil to be tested from a fluid state to a solid state is determined.

[0051] Specifically, a float equipped with a built-in inertial detection unit and a temperature sensor can be placed in a container filled with crude oil to be tested. The inertial detection unit may include a microelectromechanical system accelerometer and / or a microelectromechanical system gyroscope for collecting the float's motion data; the temperature sensor is used to collect the temperature data of the crude oil to be tested.

[0052] The density of the float is slightly lower than that of the crude oil being tested, causing the float to be suspended or floating in the fluid state of the crude oil. Thus, when the crude oil is in a fluid state, the float can move freely with the flow of the crude oil, allowing its motion to accurately reflect the flow characteristics of the crude oil; as the crude oil gradually solidifies and loses its fluidity, the motion of the float also changes accordingly.

[0053] In one possible implementation, the density of the float can be selected based on the density of the crude oil to be tested, ensuring that the float remains suspended or floating in the crude oil. For example, a float with a higher density can be selected for crude oil with a higher density; a float with a lower density can be selected for crude oil with a lower density. The difference between the density of the float and the density of the crude oil to be tested can be set according to actual testing requirements, and this application embodiment does not specifically limit this.

[0054] Optionally, the physical device of the crude oil pour point detection device 101 can be a server, a terminal, or other types of electronic equipment, and this application embodiment does not limit it in this way.

[0055] Optionally, the aforementioned terminal may be a device that provides voice and / or data connectivity to a user, a handheld device with wireless connectivity, or other processing device connected to a wireless modem. The wireless terminal may communicate with one or more core networks via a radio access network (RAN). The wireless terminal may be a mobile terminal, such as a mobile phone (or "cellular" phone) and a computer with a mobile terminal, or a portable, pocket-sized, handheld, computer-embedded, or vehicle-mounted mobile device that exchanges voice and / or data with the radio access network, such as a mobile phone, tablet computer, laptop computer, netbook, or personal digital assistant (PDA).

[0056] Optionally, the server mentioned above can be one of the servers in a server cluster (composed of multiple servers), a chip in the server, a system-on-a-chip in the server, or a virtual machine (VM) deployed on a physical machine. This application embodiment does not limit this.

[0057] Optionally, the crude oil pour point detection device 101 and the float 102 can be two independent devices or integrated into the same device. When the crude oil pour point detection device 101 and the float 102 are integrated into the same device, the crude oil pour point detection device 101 can be a processor inside the float 102.

[0058] It is easy to understand that when the crude oil pour point detection device 101 and the float 102 are integrated into the same device, the communication method between the crude oil pour point detection device 101 and the float 102 is the same as the communication method between internal modules of the device. In this case, the communication process between the two is the same as when the crude oil pour point detection device 101 and the float 102 are independent of each other.

[0059] It should be noted that the system architecture and application scenarios described in the embodiments of this application are for the purpose of more clearly illustrating the technical solutions of the embodiments of this application, and do not constitute a limitation on the technical solutions provided in the embodiments of this application. As those skilled in the art will know, with the evolution of system architecture and the emergence of new business scenarios, the technical solutions provided in the embodiments of this application are also applicable to similar technical problems. For ease of understanding, this application uses the example of crude oil pour point detection equipment 101 and float 102 operating independently for illustration.

[0060] The crude oil pour point detection method provided in the embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0061] The crude oil pour point detection method provided in this application embodiment is applied to... Figure 1The crude oil pour point detection device 101 in the crude oil pour point detection system shown is as follows: Figure 2 As shown in the embodiments of this application, a method for detecting the pour point of crude oil includes: S201. In response to the displacement disturbance excitation applied to the crude oil to be tested, acquire the motion data of the float placed in the crude oil to be tested and the temperature data of the crude oil to be tested.

[0062] In some embodiments, the displacement disturbance excitation (also known as active excitation) is applied after the cooling of the crude oil under test is paused after each preset temperature step and while the crude oil under test is in a constant temperature state.

[0063] For example, the crude oil to be tested is cooled at a uniform rate, which can be controlled between 0.1℃ / min and 1.0℃ / min. During the cooling process, an intermittent excitation strategy is adopted: after each preset step size ΔT of cooling, the cooling is paused and held at a constant temperature for a period of time t_hold, and then a displacement perturbation excitation is applied to the crude oil to be tested under the constant temperature state.

[0064] The preset step size ΔT can be set according to the required detection accuracy, for example, it can be set to any value between 0.2℃ and 0.5℃. The isothermal holding time t_hold can be set according to the thermal conductivity characteristics of the crude oil being tested, for example, it can be set to any value between 30 seconds and 120 seconds to ensure a uniform temperature distribution inside the crude oil being tested.

[0065] The aforementioned displacement disturbance excitation refers to applying a controllable, small-amplitude displacement disturbance to the crude oil under test, causing the float to produce a corresponding motion response.

[0066] In some embodiments, the displacement disturbance excitation includes at least one of the following: sinusoidal displacement disturbance excitation, step displacement disturbance excitation, and pulse displacement disturbance excitation.

[0067] Sinusoidal displacement perturbation excitation refers to applying a sinusoidal displacement perturbation with amplitude A and frequency f to the crude oil under test, causing the crude oil to produce periodic displacement changes. Among them, amplitude A can be set to any value between 0.5 mm and 2 mm, and frequency f can be set to any value between 0.1 Hz and 2 Hz.

[0068] Step displacement disturbance excitation refers to applying a sudden displacement step to the crude oil under test, and then keeping the displacement position unchanged, so that the crude oil under test produces an instantaneous displacement change.

[0069] Pulse displacement perturbation excitation refers to applying a brief, single pulse displacement perturbation to the crude oil under test, causing the crude oil to produce an instantaneous impact response.

[0070] While applying displacement disturbance excitation, the temperature data T of the crude oil to be tested can be collected in real time by the temperature sensor built into the float; the motion data of the float can be collected by the inertial detection unit built into the float, which may include the three-axis acceleration data and / or angular velocity data of the float; at the same time, the excitation parameters of the applied displacement disturbance excitation, such as the waveform, amplitude, frequency and other characteristic parameters of the excitation, are recorded so as to facilitate subsequent analysis of the dynamic response relationship between the float motion data and the excitation parameters.

[0071] The float sends the collected temperature and motion data to the crude oil pour point detection equipment, which simultaneously acquires the excitation parameters applied by the excitation device, thereby obtaining multi-source data for subsequent analysis.

[0072] It should be noted that the specific values ​​of the above-mentioned cooling rate, preset step size ΔT, constant temperature holding time t_hold, amplitude A and frequency f of sinusoidal displacement disturbance excitation are only illustrative examples. In practical applications, they can be adjusted according to the properties of the crude oil to be tested and the detection accuracy requirements. This application embodiment does not make specific limitations in this regard.

[0073] By employing the aforementioned cooling strategy and displacement perturbation excitation method, this embodiment of the application can acquire motion response data of a float under controlled displacement perturbation excitation at multiple temperature points during the cooling process of the crude oil under test. This provides a data foundation for subsequent analysis of the changing trends of oil rheological state characteristic parameters with temperature. The specific method for determining the oil rheological state characteristic parameters based on this data in step S202 will be described in detail in subsequent embodiments.

[0074] S202. Based on the dynamic response relationship between the motion data and the excitation parameters of the displacement disturbance excitation, determine the rheological state characteristic parameters of the crude oil to be tested.

[0075] After acquiring the motion data of the float and the excitation parameters of the displacement disturbance excitation, the crude oil pour point detection equipment analyzes and processes the data to determine the characteristic parameters that can reflect the rheological state of the crude oil to be tested.

[0076] Crude oil pour point testing equipment can analyze the motion characteristics of a float under displacement disturbance excitation by analyzing the dynamic response relationship between the float's motion data and the excitation parameters of the displacement disturbance excitation. When the crude oil under test is in different states, its internal structure has different constraints on the float's motion, resulting in different characteristics in the float's motion response.

[0077] For example, when the crude oil being tested is in a fluid state, the float can move freely with the crude oil, and its motion response is strongly correlated with the displacement disturbance excitation; when the crude oil being tested gradually solidifies and loses its fluidity, the movement of the float is restricted, and the correlation between its motion response and the displacement disturbance excitation weakens or becomes distorted.

[0078] Based on the above principles, crude oil pour point testing equipment can analyze the motion response of the float from different dimensions, thereby obtaining the corresponding rheological state characteristic parameters of the oil.

[0079] For example, the relative motion amplitude of the float relative to the displacement disturbance excitation can be analyzed from the response amplitude dimension; the phase lag angle between the float response and the displacement disturbance excitation can be analyzed from the response phase dimension; the harmonic distortion rate in the float response can be analyzed from the response waveform distortion dimension; or the residual displacement ratio of the float after the step displacement disturbance excitation can be analyzed from the step response attenuation dimension.

[0080] The different characteristic parameters mentioned above can reflect the changes in the rheological properties of the crude oil under test during the cooling process from different perspectives.

[0081] For example, the relative motion amplitude can reflect the degree of resistance of the crude oil to the float motion and is used to characterize the fluidity of the crude oil; the phase hysteresis angle can reflect the viscoelastic properties of the crude oil; the harmonic distortion rate can reflect the degree of nonlinear response during the formation of the internal wax crystal network structure of the crude oil; and the residual displacement ratio can reflect the solid properties of the crude oil after being excited by a step displacement disturbance.

[0082] It should be noted that the above-mentioned characteristic parameters can be used individually or in combination to improve the accuracy and robustness of pour point determination. The specific methods for determining each characteristic parameter will be described in detail in subsequent embodiments along with specific implementation methods.

[0083] Through the above analysis and processing, the crude oil pour point detection equipment can quantify the motion response of the float into specific characteristic parameters, providing a quantitative basis for subsequent pour point determination.

[0084] S203. Determine the pour point of the crude oil to be tested based on the changing trend of the rheological state characteristic parameters of the oil with temperature data.

[0085] After acquiring the rheological state characteristic parameters of the crude oil to be tested at different temperatures, the crude oil pour point testing equipment determines the pour point of the crude oil to be tested based on the changing trend of these characteristic parameters with temperature data.

[0086] During the cooling process of the crude oil under test, its rheological state changes as the temperature gradually decreases. When the crude oil is in a fluid state, wax crystals have not yet formed or the wax crystal network structure is not fully developed. The float can move freely under displacement disturbance, and the rheological characteristic parameters of the oil are within a certain range. When the temperature drops to near a certain critical point, a wax crystal network structure begins to form inside the crude oil, the fluidity of the crude oil gradually weakens, the movement of the float is restricted, and the rheological characteristic parameters of the oil change accordingly. When the temperature continues to drop to the pour point, the crude oil under test essentially loses its macroscopic fluidity, and the rheological characteristic parameters of the oil exceed the preset threshold or undergo abrupt changes.

[0087] Crude oil pour point testing equipment can capture the above-mentioned transformation process by monitoring the changing trend of oil rheological state characteristic parameters with temperature data.

[0088] Specifically, the crude oil pour point detection equipment records the corresponding characteristic parameter values ​​at multiple temperature points, analyzes the change pattern of characteristic parameters as the temperature decreases, and determines the current temperature as the pour point of the crude oil to be tested when the change of characteristic parameters meets the preset pour point discrimination criteria.

[0089] Different rheological state characteristics of oil products correspond to different pour point determination criteria. For example, regarding relative motion amplitude, when the crude oil being tested is in a fluid state, the float can follow the displacement disturbance and move, resulting in a relatively large relative motion amplitude. As the temperature decreases, the fluidity of the crude oil being tested weakens, the float's movement is hindered, and the relative motion amplitude gradually decreases. When the relative motion amplitude first falls below a preset amplitude threshold, it indicates that the crude oil being tested has essentially lost its macroscopic fluidity, and the corresponding temperature at this point is the pour point.

[0090] Regarding the phase lag angle, when the crude oil under test is in a fluid state, the float response lags behind the displacement disturbance excitation, and the phase lag angle is relatively large. As the temperature decreases, the viscoelasticity of the crude oil under test increases, and the phase lag angle gradually decreases. When the crude oil under test transforms into an elastic solid, the float response and the displacement disturbance excitation tend to be in phase, and the phase lag angle approaches zero. When the phase lag angle is less than the preset angle threshold for the first time, it indicates that the crude oil under test has reached the pour point state, and the corresponding temperature is the pour point.

[0091] Regarding harmonic distortion rate, when the crude oil to be tested begins to form a wax crystal network structure, due to the nonlinear stick-slip effect, obvious harmonic components appear in the float response, and the harmonic distortion rate increases sharply. When the harmonic distortion rate exceeds the preset distortion rate threshold for the first time, it indicates that the crude oil to be tested has entered the pour point critical region. The corresponding temperature at this time can be used as the pour point or auxiliary criterion.

[0092] Regarding the residual displacement ratio, when the crude oil under test is in a fluid state, after a step displacement disturbance, the float can gradually return to the equilibrium position, and the residual displacement ratio is small. As the temperature decreases, the crude oil under test gradually exhibits solid characteristics. After a step displacement disturbance, the float basically does not recover, and the residual displacement ratio is large. When the residual displacement ratio exceeds the preset residual displacement ratio threshold for the first time, it indicates that the crude oil under test has solid characteristics, and the corresponding temperature is the pour point.

[0093] In some embodiments, multiple oil rheological state characteristic parameters can be combined to determine the pour point, thereby improving the accuracy and robustness of the determination. For example, the temperature corresponding to the first time the harmonic distortion rate exceeds a preset distortion rate threshold can be used as the critical warning temperature, and the temperature corresponding to the first time the phase lag angle is less than a preset angle threshold can be used as the pour point, thus forming a determination mechanism that verifies multiple criteria.

[0094] It should be noted that the aforementioned preset amplitude threshold, preset angle threshold, preset distortion rate threshold, and preset residual displacement ratio threshold can be set according to the properties of the crude oil to be tested and the detection accuracy requirements. This application embodiment does not impose specific limitations on this. The following is a detailed explanation of the method for determining the relative motion amplitude, a characteristic parameter of the rheological state of oil.

[0095] In some embodiments, the motion data includes acceleration data, and the rheological state characteristic parameters of the oil product include relative motion amplitude. The relative motion amplitude is used to characterize the fluidity of the crude oil being tested, that is, to reflect the degree to which the crude oil being tested hinders the movement of the float.

[0096] In S202 above, the specific method for determining the relative motion amplitude based on the dynamic response relationship between motion data and excitation parameters of displacement disturbance excitation may include the following steps: S202-11. Perform integral transformation on the acceleration data to obtain the float displacement time series.

[0097] The acceleration data collected by the inertial detection unit built into the float is a data sequence of the float's acceleration changing over time in three-dimensional space. Since acceleration is the second derivative of displacement, by performing a second integral on the acceleration data, a data sequence of the float's displacement changing over time can be obtained.

[0098] In practical processing, the acceleration data can be integrated once to obtain the velocity data, and then the velocity data can be integrated a second time to obtain the displacement data. During the integration process, a preset filtering algorithm can be used to remove the accumulated integration error, such as using a high-pass filter to remove low-frequency drift components, in order to obtain an accurate float displacement time series. The obtained float displacement time series is denoted as S_f(t), where t represents time.

[0099] S202-12. Determine the excitation displacement time series based on the excitation parameters of the displacement disturbance excitation.

[0100] The displacement disturbance excitation is applied by an excitation device according to preset excitation parameters, including characteristic parameters such as the waveform, amplitude, and frequency of the excitation. After acquiring these excitation parameters, the crude oil pour point detection equipment determines the excitation displacement time series based on the excitation parameters.

[0101] For example, when the applied displacement disturbance excitation is a sinusoidal displacement disturbance excitation, a corresponding sinusoidal waveform displacement time series can be generated based on its amplitude and frequency; when the applied displacement disturbance excitation is a step displacement disturbance excitation, a step waveform displacement time series can be generated, that is, the displacement changes abruptly from zero to a preset amplitude at the moment the excitation is applied, and the amplitude remains unchanged; when the applied displacement disturbance excitation is a pulse displacement disturbance excitation, a pulse waveform displacement time series can be generated, that is, a brief single displacement change occurs at the moment the excitation is applied.

[0102] This excitation displacement time series reflects the trajectory of the displacement disturbance applied to the crude oil under test over time, and serves as a benchmark for comparison with the float displacement time series. The excitation displacement time series is denoted as S_ex(t), where t represents time.

[0103] S202-13. The amplitude or root mean square value between the float displacement time series and the excitation displacement time series is determined as the relative motion amplitude.

[0104] The float displacement time series S_f(t) is compared with the excitation displacement time series S_ex(t), and the difference between the two is calculated. The relative motion amplitude ΔS is defined as the magnitude or root mean square value of the absolute value of the difference between the float displacement and the applied excitation displacement, and its mathematical expression is: The magnitude of ΔS = |S_f(t) - S_ex(t)|, or ΔS = RMS(|S_f(t) - S_ex(t)|).

[0105] Where |S_f(t)-S_ex(t)| represents the absolute value of the difference between the float displacement value and the excitation displacement value at the same moment, yielding a time series of the instantaneous displacement difference changing with time. Analyzing this time series, the maximum value of the instantaneous displacement difference within the entire excitation cycle can be taken as the amplitude of the relative motion, or the root mean square value of the instantaneous displacement difference can be calculated as the relative motion amplitude.

[0106] The amplitude calculation method reflects the maximum deviation between the float's motion and the excitation displacement, and is suitable for capturing extreme response situations; the root mean square (RMS) value calculation method reflects the average deviation over the entire excitation cycle, and is suitable for evaluating overall response characteristics. The specific calculation method used can be selected based on the properties of the crude oil being tested and the required detection accuracy; this application does not impose specific limitations on this.

[0107] Through the above steps, the crude oil pour point testing equipment can convert the acceleration data of the float into displacement data and compare it with the excitation displacement to obtain the relative motion amplitude ΔS, which quantitatively characterizes the fluidity of the crude oil under test. The trend of this relative motion amplitude with temperature can be used for subsequent pour point determination.

[0108] In some embodiments, when the rheological state characteristic parameters of the oil include relative motion amplitude, the specific method for determining the pour point of the crude oil to be tested in S203 above, based on the changing trend of the rheological state characteristic parameters of the oil with temperature data, may include the following steps: S203-11. Based on the trend of relative motion amplitude with temperature data, the temperature data corresponding to the first time the relative motion amplitude falls below the preset amplitude threshold as the temperature data decreases is determined as the pour point of the crude oil to be tested.

[0109] The crude oil pour point testing equipment acquires the corresponding relative motion amplitude ΔS at multiple temperature points, establishing the relationship between the relative motion amplitude and temperature data. As the temperature of the crude oil under test gradually decreases, its fluidity gradually weakens, and the difference between the motion response of the float under displacement disturbance excitation and the excitation displacement gradually increases, resulting in a gradually increasing trend in the relative motion amplitude ΔS.

[0110] When the temperature of the crude oil being tested drops to near a certain critical temperature, a wax crystal network structure begins to form inside the crude oil, significantly reducing its fluidity and severely restricting the movement of the float, thus further increasing the relative movement amplitude ΔS. When the temperature drops to the pour point, the crude oil being tested essentially loses its macroscopic fluidity, and the float can hardly follow the displacement disturbance excitation movement; at this point, the relative movement amplitude ΔS reaches a relatively large value.

[0111] In the actual judgment process, a preset amplitude threshold ΔS_th is set in advance. This preset amplitude threshold can be set according to the properties of the crude oil to be tested and the detection accuracy requirements. For example, it can be determined by calibration tests on standard oil samples with known pour points. When the relative motion amplitude ΔS first falls below the preset amplitude threshold ΔS_th as the temperature decreases, it indicates that the crude oil to be tested has lost its macroscopic fluidity at that temperature. The corresponding temperature data T_c at this time is the pour point of the crude oil to be tested.

[0112] It should be noted that, in the above determination process, the physical meaning of the increase in relative motion amplitude ΔS as temperature decreases is that as the crude oil being tested transitions from a fluid state to a solid state, the difference between the float motion and the excitation displacement becomes increasingly larger, thus the relative motion amplitude ΔS gradually increases. When ΔS exceeds the preset amplitude threshold ΔS_th, the crude oil being tested is determined to have lost its fluidity, and the corresponding temperature is the pour point. The above statement of "first less than" is based on the mathematical relationship between relative motion amplitude and the threshold, which in actual physical processes manifests as the relative motion amplitude exceeding the preset amplitude threshold for the first time.

[0113] In this way, the crude oil pour point testing equipment can quantitatively determine the pour point of the crude oil under test by using the characteristic parameter of relative motion amplitude, avoiding the subjective error of traditional manual testing methods and improving the objectivity and accuracy of the test.

[0114] The following section provides a detailed explanation of how to determine the phase hysteresis angle, a characteristic parameter of oil rheological state.

[0115] In some embodiments, the motion data includes a motion response signal generated in response to displacement disturbance excitation, and the oil rheological state characteristic parameters include a phase hysteresis angle. The phase hysteresis angle is used to characterize the viscoelastic properties of the crude oil under test, that is, to reflect the delayed response of the internal structure of the crude oil to the float motion under displacement disturbance excitation.

[0116] In S202 above, the specific method for determining the phase lag angle based on the dynamic response relationship between motion data and excitation parameters of displacement disturbance excitation may include the following steps: S202-21. Obtain the excitation signal for displacement disturbance excitation.

[0117] The displacement disturbance excitation is applied by an excitation device according to preset excitation parameters, including characteristic parameters such as waveform, amplitude, and frequency. After acquiring these excitation parameters, the crude oil pour point detection equipment determines the excitation signal for the displacement disturbance excitation. This excitation signal reflects the waveform of the displacement disturbance applied to the crude oil under test as a function of time, and serves as a benchmark for comparative analysis with the float motion response signal. The excitation signal is denoted as S_ex(t), where t represents time.

[0118] For example, when the applied displacement disturbance excitation is a sinusoidal displacement disturbance excitation, the excitation signal is a sinusoidal waveform signal; when the applied displacement disturbance excitation is a step displacement disturbance excitation, the excitation signal is a step waveform signal; and when the applied displacement disturbance excitation is a pulse displacement disturbance excitation, the excitation signal is a pulse waveform signal.

[0119] S202-22. Based on the correlation characteristics between the motion response signal and the excitation signal, determine the lag phase of the motion response signal relative to the excitation signal, and define the lag phase as the phase lag angle.

[0120] The inertial detection unit built into the float collects the float's motion response signal under displacement disturbance excitation. This motion response signal may include acceleration response signal, velocity response signal, or displacement response signal. The motion response signal is denoted as S_f(t), where t represents time.

[0121] The crude oil pour point testing equipment performs correlation analysis on the excitation signal S_ex(t) and the motion response signal S_f(t) to calculate the phase lag angle φ between them. In practical processing, cross-correlation analysis can be used to calculate the cross-correlation function between the excitation signal and the motion response signal, determine the position corresponding to the peak of the cross-correlation function, and the phase angle corresponding to this peak is the phase lag angle φ, whose mathematical expression is: φ=arg[max(cross-correlation(S_f(t),S_ex(t)))]; Here, cross-correlation represents cross-correlation operation, max represents taking the maximum value, and arg represents taking the phase angle corresponding to the maximum value.

[0122] The phase lag angle φ reflects the viscoelastic properties of the crude oil being tested. When the crude oil is in the high-temperature fluid region, its viscous properties dominate, and the motion response of the float lags significantly relative to the displacement disturbance excitation, resulting in a large phase lag angle φ, typically ranging from 10° to 30°. As the temperature gradually decreases, wax crystals begin to precipitate in the crude oil and gradually form a network structure, enhancing its elastic properties and weakening its viscous properties. The lag between the float's motion response and the displacement disturbance excitation gradually decreases, and the phase lag angle φ shows a gradually decreasing trend. When the crude oil transforms into an elastic solid, the float's response and the displacement disturbance excitation tend to be in phase, and the phase lag angle φ approaches 0°.

[0123] Through the above steps, the crude oil pour point testing equipment can obtain the hysteresis phase of the float motion response signal relative to the displacement disturbance excitation signal, thereby obtaining the phase hysteresis angle φ, which quantitatively characterizes the viscoelastic properties of the crude oil under test. The trend of this phase hysteresis angle with temperature can be used for subsequent pour point determination.

[0124] In some embodiments, when the rheological state characteristic parameters of the oil include the phase hysteresis angle, the specific method for determining the pour point of the crude oil to be tested in S203 above, based on the changing trend of the rheological state characteristic parameters of the oil with temperature data, may include the following steps: S203-21. Based on the trend of the phase lag angle changing with temperature data, the temperature data corresponding to the first time the phase lag angle is less than the preset angle threshold as the temperature data decreases is determined as the pour point of the crude oil to be tested.

[0125] The crude oil pour point detection equipment acquires the corresponding phase lag angle φ at multiple temperature points, establishing the relationship between the phase lag angle and temperature data. As the temperature of the crude oil under test gradually decreases, the phase lag angle φ gradually decreases from its maximum value in the high-temperature region. When the temperature drops to near a certain critical temperature, the phase lag angle φ decreases to below a preset angle threshold.

[0126] In the actual judgment process, a preset angle threshold φ_th is set in advance. This preset angle threshold can be set according to the properties of the crude oil to be tested and the detection accuracy requirements, for example, it can be set to 2°. When the phase lag angle φ first falls below the preset angle threshold φ_th as the temperature decreases, it indicates that the crude oil to be tested has basically exhibited solid characteristics at that temperature, and the float response and displacement disturbance excitation tend to be in phase. The corresponding temperature data T_c at this time is the pour point of the crude oil to be tested.

[0127] In some embodiments, after the phase hysteresis angle is first less than a preset angle threshold, the temperature can continue to drop and the phase hysteresis angle can be monitored to ensure it remains stable (e.g., continuously less than the preset angle threshold) in order to verify the accuracy of the freezing point determination.

[0128] In this way, the crude oil pour point detection equipment can quantitatively determine the pour point of the crude oil under test by using the characteristic parameter of phase lag angle. This determination method is based on the phase relationship between the float response and the excitation, which has a clear physical meaning and the detection results are objective and reliable.

[0129] The following section provides a detailed explanation of how to determine the harmonic distortion rate, a characteristic parameter of oil rheological state.

[0130] In some embodiments, the motion data includes acceleration data, and the rheological state characteristic parameters of the oil product include harmonic distortion rate. The harmonic distortion rate is used to characterize the degree of nonlinear response during the formation of the wax crystal network structure within the crude oil under test, that is, to reflect the nonlinear distortion characteristics of the crude oil under test caused by the formation of the wax crystal network structure under displacement disturbance excitation.

[0131] In step S202 above, the specific method for determining the harmonic distortion rate based on the dynamic response relationship between motion data and excitation parameters of displacement disturbance excitation may include the following steps: S202-31. Perform frequency domain transformation on the acceleration data to obtain the spectral distribution.

[0132] The acceleration data collected by the inertial detection unit built into the float is the float's acceleration response signal in the time domain. To analyze the frequency components of the acceleration response, the acceleration data needs to be frequency domain transformed. Crude oil pour point detection equipment can use the Fast Fourier Transform algorithm to convert the time-domain acceleration response signal into a frequency-domain spectral distribution, obtaining the power or amplitude distribution of the acceleration response at different frequencies.

[0133] The frequency spectrum distribution after frequency domain transformation can clearly show the energy distribution characteristics of each frequency component in the acceleration response, including the fundamental frequency component that is the same as the excitation frequency of the displacement disturbance, as well as the harmonic components (such as second harmonics, third harmonics, etc.) generated by the nonlinear response.

[0134] S202-32. Based on the spectrum distribution, determine the fundamental frequency power and the power of each harmonic corresponding to the excitation frequency.

[0135] After obtaining the spectral distribution of the acceleration response, the crude oil pour point detection equipment extracts the power corresponding to the excitation frequency of the displacement disturbance excitation from the spectral distribution as the fundamental frequency power, denoted as P1. At the same time, it extracts the power corresponding to integer multiples of the excitation frequency (such as the second harmonic, third harmonic, etc.) as the harmonic power of each order, denoted as P2, P3, ..., P_N, where N represents the highest harmonic order considered.

[0136] The fundamental frequency power reflects the response intensity of the float at the displacement disturbance excitation frequency, while the harmonic power reflects the distortion component in the float response caused by the nonlinear characteristics of the crude oil being tested. When the crude oil being tested is in a fluid state, its linear characteristics are good, the harmonic components are few, and the harmonic power is small. When a wax crystal network structure begins to form inside the crude oil being tested, due to the nonlinear stick-slip effect, obvious harmonic components appear in the float response, and the harmonic power increases significantly.

[0137] S202-33. Determine the harmonic distortion rate based on the ratio of fundamental frequency power to each harmonic power.

[0138] Harmonic distortion (THD) is used to quantify the proportion of harmonic components relative to the fundamental frequency component in the float's response signal, reflecting the degree of nonlinear distortion of the signal. The formula for calculating Total Harmonic Distortion (THD) is: THD=√(P2+P3+…+P_N) / P1×100%; Where P1 is the fundamental frequency power, and P2, P3, ..., P_N are the harmonic powers. This ratio reflects the ratio of the total energy of the harmonic components to the energy of the fundamental frequency components, expressed as a percentage. The higher the harmonic distortion rate, the more significant the nonlinear distortion component in the float response signal, and the stronger the nonlinear response of the wax crystal network structure inside the crude oil being tested.

[0139] Through the above steps, the crude oil pour point testing equipment can extract the harmonic distortion rate, a characteristic parameter, from the acceleration response of the float. This parameter is used to quantify the degree of nonlinear response of the crude oil under test during the formation of the wax crystal network structure. The trend of this harmonic distortion rate with temperature can be used for subsequent pour point determination.

[0140] In some embodiments, when the rheological state characteristic parameters of the oil include harmonic distortion rate, the specific method for determining the pour point of the crude oil to be tested in S203 above, based on the changing trend of the rheological state characteristic parameters of the oil with temperature data, may include the following steps: S203-31. Based on the trend of harmonic distortion rate with temperature data, the temperature data corresponding to the first time the harmonic distortion rate exceeds the preset distortion rate threshold is determined as the pour point of the crude oil to be tested.

[0141] The crude oil pour point testing equipment acquires the corresponding harmonic distortion rate (THD) at multiple temperature points, establishing the relationship between the harmonic distortion rate and temperature data. As the temperature of the crude oil under test gradually decreases, a wax crystal network structure begins to form inside it. Due to the nonlinear "stick-slip" effect, obvious harmonic components appear in the float response, and the harmonic distortion rate (THD) shows a gradually increasing trend.

[0142] When the crude oil being tested is in a high-temperature fluid state, its linear characteristics are good, the harmonic components in the float response are few, and the harmonic distortion rate (THD) is small, typically at a low level. When the temperature decreases to near the temperature at which wax crystals begin to precipitate, a wax crystal network structure begins to form inside the crude oil, resulting in nonlinear distortion in the float response and an increase in the THD. As the temperature continues to decrease to the critical pour point, the wax crystal network structure gradually develops and matures, the degree of nonlinear response intensifies, and the THD increases sharply.

[0143] In the actual judgment process, a preset distortion rate threshold THD_th is set in advance. This preset distortion rate threshold can be set according to the properties of the crude oil to be tested and the detection accuracy requirements, for example, it can be set to 5%. When the harmonic distortion rate THD exceeds the preset distortion rate threshold THD_th for the first time as the temperature decreases, it indicates that a significant wax crystal network structure has formed inside the crude oil to be tested, and it has entered the critical pour point region.

[0144] It should be noted that harmonic distortion rate can serve as an auxiliary early warning criterion for entering the pour point critical zone, and can be combined with phase lag angle criteria for comprehensive determination. For example, the temperature corresponding to the first time the harmonic distortion rate exceeds a preset distortion rate threshold can be used as the early warning temperature for entering the pour point critical zone. When the phase lag angle further falls below a preset angle threshold for the first time, this temperature point is comprehensively determined as the pour point of the crude oil being tested. By fusing multiple characteristic parameters, the accuracy and robustness of pour point detection can be improved.

[0145] In this way, the crude oil pour point detection equipment can use the characteristic parameter of harmonic distortion rate to quantitatively determine the pour point critical state of the crude oil to be tested. This determination method can capture the nonlinear response in the early stage of wax crystal network structure formation, and has early warning capability, which helps to identify the pour point critical state in advance.

[0146] The following section details the method for determining the residual displacement ratio, a characteristic parameter of oil rheological state.

[0147] In some embodiments, the motion data includes acceleration data, and the rheological state characteristic parameters of the oil product include the residual displacement ratio. The residual displacement ratio characterizes the solid properties of the crude oil under test after being subjected to a step displacement disturbance, reflecting the constraint and recovery capabilities of the internal structure of the crude oil under test on the float motion under the action of a step displacement disturbance.

[0148] In S202 above, the specific method for determining the residual displacement ratio based on the dynamic response relationship between motion data and excitation parameters of displacement disturbance excitation may include the following steps: S202-41. Perform integral transformation on the acceleration data to obtain the float displacement time series.

[0149] The acceleration data collected by the inertial detection unit built into the float is a data sequence of the float's acceleration changing over time in three-dimensional space. Since acceleration is the second derivative of displacement, by performing a second integral on the acceleration data, a data sequence of the float's displacement changing over time can be obtained.

[0150] In practical processing, the acceleration data can be integrated once to obtain the velocity data, and then the velocity data can be integrated a second time to obtain the displacement data. During the integration process, a preset filtering algorithm can be used to remove the accumulated integration error, such as using a high-pass filter to remove low-frequency drift components, in order to obtain an accurate float displacement time series. The obtained float displacement time series is denoted as S_f(t), where t represents time.

[0151] S202-42. Based on the float displacement time series, determine the peak displacement and stable residual displacement of the float after being excited by a step displacement disturbance.

[0152] When the applied displacement disturbance excitation is a step displacement disturbance excitation, the float first generates an instantaneous displacement response under the step excitation, reaching a maximum value, which is the peak displacement, denoted as S_f(peak). Subsequently, under the action of the internal damping and elastic restoring force of the crude oil being tested, the float gradually recovers from the peak position to the equilibrium position, and after a period of time, it tends to stabilize. The stable displacement value is the stable residual displacement, denoted as S_f(∞).

[0153] Peak displacement reflects the instantaneous response amplitude of the float under step displacement disturbance excitation and is related to the viscoelastic properties of the crude oil being tested. Steady residual displacement reflects the final position of the float after step excitation and is related to the solid properties of the crude oil. When the crude oil is in a fluid state, it has good fluidity, and the float can gradually recover to a position close to equilibrium after step excitation, resulting in a small steady residual displacement. When the crude oil gradually solidifies and loses fluidity, the float is essentially unable to recover after step excitation, resulting in a larger steady residual displacement, close to the peak displacement.

[0154] S202-43. The ratio of the stable residual displacement to the peak displacement is determined as the residual displacement ratio.

[0155] The residual displacement ratio R is defined as the ratio of the stable residual displacement to the peak displacement of the float after a step displacement disturbance excitation, and its mathematical expression is: R = S_f(∞) / S_f(peak); Where S_f(peak) is the peak displacement of the float after a step excitation, and S_f(∞) is the residual displacement of the float after stabilization. This ratio reflects the degree of recovery of the float after a step excitation. The closer the ratio is to 0, the stronger the float's recovery ability and the more obvious the fluid characteristics of the crude oil being tested; the closer the ratio is to 1, the more obvious the solid characteristics of the crude oil being tested.

[0156] Through the above steps, the crude oil pour point testing equipment can extract the residual displacement ratio, a characteristic parameter, from the acceleration response of the float. This parameter is used to quantify the solid properties of the crude oil under test after a step displacement disturbance. The trend of this residual displacement ratio with temperature can be used for subsequent pour point determination.

[0157] In some embodiments, when the rheological state characteristic parameters of the oil include the residual displacement ratio, the specific method for determining the pour point of the crude oil to be tested in S203 above, based on the changing trend of the rheological state characteristic parameters of the oil with temperature data, may include the following steps: S203-41. Based on the trend of the residual displacement ratio with temperature data, the temperature data corresponding to the first time the residual displacement ratio exceeds the preset residual displacement ratio threshold is determined as the pour point of the crude oil to be tested.

[0158] The crude oil pour point testing equipment acquires the corresponding residual displacement ratio R at multiple temperature points, establishing the relationship between the residual displacement ratio and temperature data. As the temperature of the crude oil under test gradually decreases, its fluidity gradually weakens, its solid properties gradually increase, and the recovery ability of the float after step displacement disturbance excitation gradually decreases, resulting in a gradual increase in the residual displacement ratio R.

[0159] When the crude oil under test is in a high-temperature fluid state, it exhibits good fluidity. The float can quickly recover to its equilibrium position after a step displacement disturbance, with a small stable residual displacement S_f(∞) and a small residual displacement ratio R, typically close to 0. As the temperature gradually decreases, a wax crystal network structure begins to form inside the crude oil, changing its viscoelastic properties. The float's recovery ability gradually weakens, the stable residual displacement gradually increases, and the residual displacement ratio R gradually increases. When the temperature drops to the pour point, the crude oil essentially loses its macroscopic fluidity and exhibits solid characteristics. The float essentially does not recover after a step displacement disturbance, the stable residual displacement S_f(∞) approaches the peak displacement S_f(peak), and the residual displacement ratio R approaches 1.

[0160] In the actual judgment process, a preset residual displacement ratio threshold R_th is set in advance. This preset residual displacement ratio threshold can be set according to the properties of the crude oil to be tested and the detection accuracy requirements, for example, it can be set to 20%. When the residual displacement ratio R first exceeds the preset residual displacement ratio threshold R_th as the temperature decreases, it indicates that the crude oil to be tested has solid characteristics at that temperature, and the float basically does not recover after the step displacement disturbance excitation. The corresponding temperature data T_c at this time is the pour point of the crude oil to be tested.

[0161] In some embodiments, the decay time constant τ of the float response recovering from the peak to the equilibrium position can also be analyzed as an auxiliary criterion. The decay time constant τ reflects the recovery speed of the float. As the crude oil under test gradually solidifies, the decay time constant increases, indicating that the recovery process slows down, further verifying the solidity characteristics of the crude oil under test.

[0162] In this way, the crude oil pour point testing equipment can quantitatively determine the pour point of the crude oil under test by using the residual displacement ratio as a characteristic parameter. This determination method is based on the recovery characteristics of the float after step displacement disturbance excitation, with clear physical meaning and objective and reliable test results.

[0163] In some embodiments, after determining the freezing point, the temperature can be further reduced to 2°C to 3°C below the freezing point, and the above steps can be repeated to verify whether the characteristic parameters remain stable at a lower temperature (e.g., the phase lag angle is continuously less than a preset angle threshold, and the relative motion amplitude is continuously greater than a preset amplitude threshold) to confirm the accuracy of the freezing point determination.

[0164] In summary, the embodiments of this application replace manual visual observation with the motion data of the float, and use quantitative data as the basis for judgment, thereby eliminating the interference of human factors on the test results and realizing the digitization and standardization of pour point determination.

[0165] Secondly, the displacement disturbance excitation applied in the embodiments of this application is a controllable small disturbance. Compared with the methods in the prior art that require the application of large disturbances or destructive operations, it reduces the shear damage to the wax crystal network structure inside the crude oil, so that the measured pour point is closer to the pour point of crude oil in the real static state.

[0166] Furthermore, the embodiments of this application can combine multiple characteristic parameters such as relative motion amplitude, phase lag angle, harmonic distortion rate, and residual displacement ratio for comprehensive discrimination, avoiding the risk of misjudgment based on a single parameter and improving the accuracy and robustness of pour point determination.

[0167] Furthermore, the embodiments of this application, through the continuous acquisition of the motion data and temperature data of the float, can continuously monitor the changes in the state of crude oil during the cooling process, without the need for complex mechanical structures. It can be applied to pipeline bypass or in-situ monitoring of storage tanks, providing a technical basis for realizing online and real-time monitoring of the pour point of crude oil.

[0168] The parameters such as harmonic distortion rate in the embodiments of this application can capture early signals of wax crystal network structure formation before the crude oil under test is completely solidified, providing early warning information for production.

[0169] In summary, the crude oil pour point detection method provided in this application, through the inertial response characteristics of the float, achieves objective, accurate, and non-destructive detection of crude oil pour point, and has good prospects for industrial application.

[0170] The crude oil pour point detection method provided in this application will be described in detail below with specific examples.

[0171] Example 1: Condensation point test based on phase lag angle discrimination.

[0172] A sample of waxy crude oil was placed in a test container. The float is equipped with a microelectromechanical system accelerometer (range ±2g, sampling rate 200Hz) and a PT100 temperature sensor.

[0173] Set the cooling program: starting from 50℃, cool at a uniform rate of 0.5℃ / min, pausing the cooling process after every 0.5℃ decrease and holding the temperature constant for 60 seconds. At the end of each constant temperature holding phase, apply a sinusoidal displacement perturbation excitation with an amplitude of 1mm and a frequency of 0.5Hz to the crude oil under test, for three cycles.

[0174] Simultaneously with the application of displacement perturbation excitation, the acceleration data of the float and the temperature data of the crude oil to be tested are collected. The acceleration data is processed by double integration to obtain the float displacement time series, and cross-correlation analysis is performed with the excitation displacement time series to calculate the phase lag angle φ.

[0175] Record the phase hysteresis angle φ values ​​at different temperatures: At 50℃, φ=28.3°; At 40℃, φ = 21.7°; At 30℃, φ=12.5°; At 25℃, φ = 6.2°; At 24.5℃, φ=3.8°; At 24.0℃, φ=1.6°; At 23.5℃, φ=1.4°.

[0176] The phase lag angle threshold φ_th was set to 2°. When the temperature dropped to 24.0℃, the phase lag angle φ first fell below 2° (the measured value was 1.6°), and this temperature was determined to be the pour point of the crude oil being tested. Further cooling to 23.0℃ maintained the phase lag angle below 1.5°, verifying the accuracy of the pour point determination.

[0177] Example 2: Multi-parameter fusion discrimination (phase lag angle combined with harmonic distortion rate).

[0178] Using the same test conditions and data processing methods as in Example 1, the acceleration signal of the float was analyzed by fast Fourier transform to calculate the total harmonic distortion (THD).

[0179] Record the phase lag angle φ and total harmonic distortion (THD) values ​​at different temperatures: At 30.0℃, φ=12.5°, THD=0.8%, the crude oil being tested is in a fluid state; At 25.0℃, φ=6.2°, THD=1.5%, the crude oil to be tested is in a fluid state; At 24.5℃, φ=3.8°, THD=3.2%, the crude oil to be tested has entered the critical state; At 24.2℃, φ=2.5°, THD=6.8%, the crude oil under test is in a critical state; At 24.0℃, φ=1.6°, THD=12.3%, the crude oil being tested is in a solidified state; At 23.5℃, φ=1.4°, THD=14.1%, the crude oil being tested is in a solidified state.

[0180] The preset distortion rate threshold THD_th is set to 5%. When the temperature drops to 24.2℃, the total harmonic distortion (THD) exceeds 5% for the first time (reaching 6.8%), triggering a critical warning. When the temperature drops to 24.0℃, the phase lag angle φ is less than 2° for the first time (reaching 1.6%), and the THD reaches 12.3%. Based on these factors, the pour point of the crude oil being tested is determined to be 24.0℃.

[0181] Example 3: The effect of different excitation frequencies.

[0182] The same crude oil sample and cooling procedure as in Example 1 were used, but sinusoidal displacement perturbation excitations of 0.2Hz, 0.5Hz, and 1.0Hz were used for testing during different isothermal holding stages.

[0183] Test results show that: when using low-frequency excitation (0.2Hz), the phase lag angle is more sensitive to changes and can capture changes in the rheological state of the crude oil being tested earlier, but the test time is longer; when using medium-frequency excitation (0.5Hz), the phase lag angle and harmonic distortion rate have good synchronization, and can obtain relatively accurate phase information and distortion information at the same time; when using high-frequency excitation (1.0Hz), the float response signal is greatly affected by inertia, and the phase lag angle is too large in the fluid region, which may affect the accuracy of the judgment.

[0184] Based on comprehensive comparison, the optimal excitation frequency range of 0.3Hz to 0.8Hz is selected to obtain the best discrimination effect.

[0185] The foregoing mainly describes the solutions provided by the embodiments of this application from a methodological perspective. To achieve the above functions, it includes corresponding hardware structures and / or software modules for executing each function. Those skilled in the art should readily recognize that, based on the units and algorithm steps of the examples described in conjunction with the embodiments disclosed herein, this application can be implemented in hardware or a combination of hardware and computer software. Whether a function is executed in hardware or by computer software driving hardware depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0186] This application embodiment can divide the crude oil pour point detection device into functional modules according to the above method example. For example, each function can be divided into its own functional module, or two or more functions can be integrated into one processing module. The integrated module can be implemented in hardware or as a software functional module. Optionally, the module division in this application embodiment is illustrative and only represents one logical functional division; other division methods may be used in actual implementation.

[0187] Figure 3 This is a schematic diagram of a crude oil pour point detection device provided in an embodiment of this application. Figure 3 As shown, the crude oil pour point detection device includes a communication unit 301 and a processing unit 302.

[0188] The communication unit 301 is used to acquire motion data of a float placed in the crude oil to be tested and temperature data of the crude oil to be tested in response to a displacement disturbance excitation applied to the crude oil to be tested. The processing unit 302 is used to determine the rheological state characteristic parameters of the crude oil to be tested based on the dynamic response relationship between the motion data and the excitation parameters of the displacement disturbance excitation. The processing unit 302 is also used to determine the pour point of the crude oil to be tested based on the changing trend of the rheological state characteristic parameters of the oil with temperature data.

[0189] In some embodiments, the displacement disturbance excitation is applied after pausing the cooling process for each preset temperature step of the crude oil under test, and while the crude oil under test is in a constant temperature state; the displacement disturbance excitation includes at least one of the following: sinusoidal displacement disturbance excitation, step displacement disturbance excitation, and pulse displacement disturbance excitation.

[0190] In some embodiments, the motion data includes: acceleration data; the rheological state characteristic parameters of the oil product include relative motion amplitude; the relative motion amplitude is used to characterize the fluidity of the crude oil to be tested; Processing unit 302 is specifically used for: The acceleration data is integrated and transformed to obtain the float displacement time series. Determine the excitation displacement time series based on the excitation parameters of the displacement disturbance excitation; The amplitude or root mean square value between the float displacement time series and the excitation displacement time series is determined as the relative motion amplitude.

[0191] In some embodiments, the processing unit 302 is specifically used for: Based on the trend of relative motion amplitude with temperature data, the temperature data corresponding to the first time the relative motion amplitude falls below the preset amplitude threshold as the temperature data decreases is determined as the pour point of the crude oil to be tested.

[0192] In some embodiments, the motion data includes: a motion response signal generated in response to displacement disturbance excitation; and oil rheological state characteristic parameters including a phase hysteresis angle; the phase hysteresis angle is used to characterize the viscoelasticity of the crude oil under test. Processing unit 302 is specifically used for: Obtain the excitation signal for displacement disturbance excitation; Based on the correlation characteristics between the motion response signal and the excitation signal, the lag phase of the motion response signal relative to the excitation signal is determined, and the lag phase is defined as the phase lag angle.

[0193] In some embodiments, the processing unit 302 is specifically used for: Based on the trend of phase lag angle with temperature data, the temperature data corresponding to the first time the phase lag angle is less than the preset angle threshold as the temperature data decreases is determined as the pour point of the crude oil to be tested.

[0194] In some embodiments, the motion data includes: acceleration data; the rheological state characteristic parameters of the oil include harmonic distortion rate; the harmonic distortion rate is used to characterize the degree of nonlinear response during the formation of the wax crystal network structure inside the crude oil under test; Processing unit 302 is specifically used for: The acceleration data is transformed in the frequency domain to obtain the spectral distribution; Based on the spectral distribution, determine the fundamental frequency power and the power of each harmonic corresponding to the excitation frequency; The harmonic distortion rate is determined by the ratio of the fundamental frequency power to the power of each harmonic.

[0195] In some embodiments, the processing unit 302 is specifically used for: Based on the trend of harmonic distortion rate with temperature data, the temperature data corresponding to the first time the harmonic distortion rate exceeds the preset distortion rate threshold is determined as the pour point of the crude oil to be tested.

[0196] In some embodiments, motion data includes: acceleration data; oil rheological state characteristic parameters include residual displacement ratio; the residual displacement ratio is used to characterize the solid properties of the crude oil under test after being subjected to step displacement perturbation excitation; Processing unit 302 is specifically used for: The acceleration data is integrated and transformed to obtain the float displacement time series. Based on the float displacement time series, determine the peak displacement and stable residual displacement of the float after being excited by a step displacement disturbance. The ratio of the stable residual displacement to the peak displacement is defined as the residual displacement ratio.

[0197] In some embodiments, the processing unit 302 is specifically used for: Based on the trend of residual displacement ratio with temperature data, the temperature data corresponding to the first time the residual displacement ratio exceeds the preset residual displacement ratio threshold is determined as the pour point of the crude oil to be tested.

[0198] The crude oil pour point testing equipment in the crude oil pour point testing system includes, for example: Figure 4 The included components. The following are examples... Figure 4 Taking the crude oil pour point detection device shown as an example, the hardware structure of the crude oil pour point detection equipment is introduced.

[0199] Figure 4 This is a schematic diagram of the hardware structure of a crude oil pour point detection device provided in an embodiment of this application. Figure 4 As shown, the crude oil pour point detection device includes: a processor 401, a memory 402, a communication interface 403, and a bus 404. The processor 401, the memory 402, and the communication interface 403 can be connected via the bus 404.

[0200] Processor 401 is the control center of the crude oil pour point detection device. It can be a single processor or a collective term for multiple processing elements. For example, processor 401 can be a general-purpose central processing unit (CPU) or other general-purpose processors. The general-purpose processor can be a microprocessor or any conventional processor.

[0201] As one embodiment, processor 401 may include one or more CPUs, for example Figure 4 CPU0 and CPU1 are shown in the diagram.

[0202] The memory 402 may be a read-only memory (ROM) or other type of static storage device capable of storing static information and instructions, random access memory (RAM) or other type of dynamic storage device capable of storing information and instructions, or electrically erasable programmable read-only memory (EEPROM), disk storage media or other magnetic storage devices, or any other medium capable of carrying or storing desired program code in the form of instructions or data structures and accessible by a computer, but is not limited thereto.

[0203] In one possible implementation, the memory 402 can exist independently of the processor 401. The memory 402 can be connected to the processor 401 via a bus 404 and is used to store instructions or program code. When the processor 401 calls and executes the instructions or program code stored in the memory 402, it can implement the crude oil pour point detection method provided in the following embodiments of this application.

[0204] In this embodiment, the software programs stored in memory 402 differ for the crude oil pour point detection device, resulting in different functions implemented by the device. The functions performed by each device will be described in conjunction with the following flowchart.

[0205] In another possible implementation, the memory 402 can also be integrated with the processor 401.

[0206] Communication interface 403 is used for connecting the crude oil pour point detection device with other equipment via a communication network, such as Ethernet, wireless access network, or wireless local area network (WLAN). Communication interface 403 may include a receiving unit for receiving data and a transmitting unit for sending data.

[0207] Bus 404 can be an industry standard architecture (ISA) bus, a peripheral component interconnect (PCI) bus, or an extended industry standard architecture (EISA) bus. This bus can be divided into address bus, data bus, control bus, etc. For ease of representation, Figure 4 The bus is represented by a single thick line, but this does not mean that there is only one bus or one type of bus.

[0208] It should be pointed out that, Figure 4 The structure shown does not constitute a limitation on the crude oil pour point detection device, except Figure 4 In addition to the components shown, the crude oil pour point detection device may include more or fewer components than shown, or combine certain components, or have different component arrangements.

[0209] This application also provides a computer-readable storage medium, which includes computer-executable instructions. When the computer-executable instructions are run on a computer, the computer performs the crude oil pour point detection method provided in the above embodiments.

[0210] This application also provides a computer program that can be directly loaded into a memory and contains software code. After being loaded and executed by a computer, the computer program can implement the crude oil pour point detection method provided in the above embodiments.

[0211] Those skilled in the art will recognize that, in one or more of the examples above, the functions described in this application can be implemented using hardware, software, firmware, or any combination thereof. When implemented in software, these functions can be stored in a computer-readable medium or transmitted as one or more instructions or code on a computer-readable medium. Computer-readable media include computer-readable storage media and communication media, wherein communication media include any medium that facilitates the transmission of a computer program from one place to another. Storage media can be any available medium accessible to a general-purpose or special-purpose computer.

[0212] Through the above description of the embodiments, those skilled in the art can clearly understand that, for the sake of convenience and brevity, only the division of the above functional modules is used as an example. In actual applications, the above functions can be assigned to different functional modules as needed, that is, the internal structure of the device can be divided into different functional modules to complete all or part of the functions described above.

[0213] In the several embodiments provided in this application, it should be understood that the disclosed apparatus and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of modules or units is only a logical functional division, and other division methods may exist in actual implementation. For example, multiple units or components may be combined or integrated into another device, or some features may be ignored or not executed. Furthermore, the shown or discussed mutual couplings, direct couplings, or communication connections may be through some interfaces; indirect couplings or communication connections between devices or units may be electrical, mechanical, or other forms. Units described as separate components may or may not be physically separate; components shown as units may be one physical unit or multiple physical units, i.e., they may be located in one place or distributed in multiple different places. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0214] Furthermore, the functional units in the various embodiments of this application can be integrated into a single defect detection unit, or each unit can exist physically separately, or two or more units can be integrated into a single unit. The integrated unit can be implemented in hardware or as a software functional unit. If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a readable storage medium. Based on this understanding, the technical solution of the embodiments of this application, in essence, or the part that contributes to general technology, or all or part of the technical solution, can be embodied in the form of a software product. This software product is stored in a storage medium and includes several instructions to cause a device (which may be a microcontroller, chip, etc.) or processor to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, ROM, RAM, magnetic disks, or optical disks.

[0215] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method for detecting the pour point of crude oil, characterized in that, include: In response to a displacement disturbance excitation applied to the crude oil to be tested, the motion data of a float placed in the crude oil to be tested and the temperature data of the crude oil to be tested are acquired; Based on the dynamic response relationship between the motion data and the excitation parameters of the displacement disturbance excitation, the rheological state characteristic parameters of the crude oil to be tested are determined. The pour point of the crude oil to be tested is determined based on the changing trend of the oil rheological state characteristic parameters with the temperature data.

2. The crude oil pour point detection method according to claim 1, characterized in that, The displacement disturbance excitation is applied after pausing the cooling process for each preset temperature step of the crude oil under test, and while the crude oil under test is in a constant temperature state; the displacement disturbance excitation includes at least one of the following: sinusoidal displacement disturbance excitation, step displacement disturbance excitation, and pulse displacement disturbance excitation.

3. The crude oil pour point detection method according to claim 1, characterized in that, The motion data includes: acceleration data; the oil rheological state characteristic parameters include relative motion amplitude; the relative motion amplitude is used to characterize the fluidity of the crude oil under test; The step of determining characteristic parameters reflecting the rheological state of the crude oil under test based on the dynamic response relationship between the motion data and the excitation parameters of the displacement disturbance excitation includes: The acceleration data is integrated and transformed to obtain the float displacement time series of the float. Based on the excitation parameters of the displacement disturbance excitation, determine the excitation displacement time sequence; The amplitude or root mean square value between the float displacement time series and the excitation displacement time series is determined as the relative motion amplitude.

4. The crude oil pour point detection method according to claim 3, characterized in that, The step of determining the pour point of the crude oil to be tested based on the changing trend of the oil rheological state characteristic parameters with the temperature data includes: Based on the trend of the relative motion amplitude with the temperature data, the temperature data corresponding to the first time the relative motion amplitude falls below a preset amplitude threshold as the temperature data decreases is determined as the pour point of the crude oil to be tested.

5. The crude oil pour point detection method according to claim 1, characterized in that, The motion data includes: a motion response signal generated in response to the displacement disturbance excitation; the oil rheological state characteristic parameters include a phase hysteresis angle; the phase hysteresis angle is used to characterize the viscoelasticity of the crude oil under test; The step of determining characteristic parameters reflecting the rheological state of the crude oil under test based on the dynamic response relationship between the motion data and the excitation parameters of the displacement disturbance excitation includes: Obtain the excitation signal of the displacement disturbance excitation; Based on the correlation characteristics of the motion response signal and the excitation signal, the lag phase of the motion response signal relative to the excitation signal is determined, and the lag phase is defined as the phase lag angle.

6. The crude oil pour point detection method according to claim 5, characterized in that, The step of determining the pour point of the crude oil to be tested based on the changing trend of the oil rheological state characteristic parameters with the temperature data includes: Based on the trend of the phase lag angle changing with the temperature data, the temperature data corresponding to the first time the phase lag angle is less than a preset angle threshold as the temperature data decreases is determined as the pour point of the crude oil to be tested.

7. The crude oil pour point detection method according to claim 1, characterized in that, The motion data includes: acceleration data; the oil rheological state characteristic parameters include harmonic distortion rate; the harmonic distortion rate is used to characterize the degree of nonlinear response during the formation of the wax crystal network structure inside the crude oil under test; The step of determining characteristic parameters reflecting the rheological state of the crude oil under test based on the dynamic response relationship between the motion data and the excitation parameters of the displacement disturbance excitation includes: The acceleration data is subjected to frequency domain transformation to obtain the spectral distribution; Based on the spectrum distribution, determine the fundamental frequency power and each harmonic power corresponding to the excitation frequency; The harmonic distortion rate is determined based on the ratio of the fundamental frequency power to the power of each harmonic.

8. The crude oil pour point detection method according to claim 7, characterized in that, The step of determining the pour point of the crude oil to be tested based on the changing trend of the oil rheological state characteristic parameters with the temperature data includes: Based on the trend of the harmonic distortion rate with the temperature data, the temperature data corresponding to the first time the harmonic distortion rate exceeds the preset distortion rate threshold is determined as the pour point of the crude oil to be tested.

9. The crude oil pour point detection method according to claim 2, characterized in that, The motion data includes: acceleration data; the oil rheological state characteristic parameters include residual displacement ratio; the residual displacement ratio is used to characterize the solid properties of the crude oil under test after being subjected to the step displacement disturbance excitation; The step of determining characteristic parameters reflecting the rheological state of the crude oil under test based on the dynamic response relationship between the motion data and the excitation parameters of the displacement disturbance excitation includes: The acceleration data is integrated and transformed to obtain the float displacement time series of the float. Based on the float displacement time series, determine the peak displacement and stable residual displacement of the float after being excited by the step displacement disturbance; The ratio of the stable residual displacement to the peak displacement is determined as the residual displacement ratio.

10. The crude oil pour point detection method according to claim 9, characterized in that, The step of determining the pour point of the crude oil to be tested based on the changing trend of the oil rheological state characteristic parameters with the temperature data includes: Based on the trend of the residual displacement ratio with the temperature data, the temperature data corresponding to the first time the residual displacement ratio exceeds the preset residual displacement ratio threshold is determined as the pour point of the crude oil to be tested.

11. A crude oil pour point detection device, characterized in that, include: Communication unit and processing unit; The communication unit is used to acquire motion data of a float placed in the crude oil under test and temperature data of the crude oil under test in response to a displacement disturbance excitation applied to the crude oil under test. The processing unit is used to determine the rheological state characteristic parameters of the crude oil to be tested based on the dynamic response relationship between the motion data and the excitation parameters of the displacement disturbance excitation. The processing unit is also used to determine the pour point of the crude oil to be tested based on the changing trend of the oil rheological state characteristic parameters with the temperature data.

12. A crude oil pour point testing device, characterized in that, include: Processor and memory; The memory is used to store one or more programs, the one or more programs including computer execution instructions. When the crude oil pour point detection device is running, the processor executes the computer execution instructions stored in the memory to cause the crude oil pour point detection device to perform the method of any one of claims 1 to 10.

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