A test device for monitoring the generation of natural gas hydrate by using electric method

Abstract

The present application relates to oil and gas drilling and gathering and transportation technical field, specifically relates to a kind of test device for monitoring natural gas hydrate generation using electric method, including hydrate generation monitoring unit, electrical property detection unit, temperature and pressure detection unit, differential pressure detection unit, data acquisition unit and data processing unit.In the present application, hydrate generation monitoring unit is used to measure the electrical property parameter between two electrodes of a certain section and monitor its change rule, that is, the resistance and capacitance of liquid in the pipeline are monitored by test probe, and numerical measurement and display are carried out by LCR bridge in electrical property detection unit;At the same time, the values and change rules of temperature, pressure and pressure difference measured by temperature and pressure detection unit and differential pressure detection unit in the pipeline are combined to determine whether hydrate is generated in the pipeline.The overall monitoring system is more convenient to assemble, the monitoring result is reliable, and the precision is higher.Meanwhile, a method for monitoring natural gas hydrate generation using electric method is also provided.

Description

Technical Field

[0001] This invention relates to the field of oil and gas drilling, production, gathering and transportation technology, and specifically to a test device for monitoring the formation of natural gas hydrates using electrical methods. Background Technology

[0002] In the oil and gas industry, the formation of natural gas hydrates can cause serious flow obstructions and operational safety hazards. Natural gas hydrates are ice-like crystalline substances formed from natural gas and water under high pressure and low temperature conditions. Low-temperature and high-pressure working environments are unavoidable in the oil and gas industry, and these environments readily lead to hydrate formation. Solid hydrates not only affect the smooth operation of transportation and production but can also clog pipelines, causing damage to instruments and equipment, and even triggering dangerous situations such as breakage and explosions. Particularly in deep-water drilling and gathering, harsh weather and environmental conditions create an environment extremely conducive to the formation of hydrates and even blockages. Therefore, to prevent the serious impacts and safety hazards caused by hydrate formation, hydrate monitoring technology is needed to monitor hydrate formation.

[0003] Currently, domestic and international methods for monitoring and early warning of hydrates mainly include the conductivity-velocity of sound method, freezing point depression method, water activity method, water content method, component change method, tracer method, and visual observation method. However, these methods, under the condition of known hydrocarbon composition and pipeline conditions, measure the concentration of salt and inhibitors in the pipeline and then determine the safety margin of hydrates through a comprehensive thermodynamic model. However, effective laboratory or field verification in flowing pipelines is currently lacking. Due to the high variability in flowing pipelines, uncertainty and high error are easily caused. The freezing point depression method, water activity method, water content method, component change method, and tracer method require sampling and measurement. The high-pressure environment in the gathering and transportation pipeline causes huge shearing forces during sampling due to valve throttling, which not only damages the rheological properties and stability of the fluid but may also accelerate the formation of hydrates in the pipeline due to the Joule-Thomson effect, causing greater safety hazards. The conductivity-velocity of sound method and visual observation method are expensive in terms of equipment investment and labor costs, and are also complex to operate. Therefore, existing technologies need further improvement. Summary of the Invention

[0004] The purpose of this invention is to provide a test apparatus for monitoring the formation of natural gas hydrates using an electrical method, so as to solve the existing technical problems in the background art.

[0005] To solve the above-mentioned technical problems, the technical solution provided by the present invention is as follows:

[0006] On the one hand, an experimental device for monitoring the formation of natural gas hydrates using electrical methods is provided, including a pipeline, a hydrate formation monitoring unit for tracking changes in electrical properties within the pipeline, an electrical property detection unit for detecting changes in electrical properties within the pipeline, a temperature and pressure detection unit for detecting temperature and pressure changes at a certain point within the pipeline, a pressure difference detection unit for detecting pressure differences within the pipeline, a data acquisition unit for collecting data from the electrical property detection unit, the temperature and pressure detection unit, and the pressure difference detection unit, and a data processing unit for processing the data from the data acquisition unit to determine whether hydrates are being formed online in the pipeline.

[0007] Based on the above technical solution, the hydrate formation monitoring unit includes a connecting body, a first test probe, and a second test probe. The connecting body is sleeved on the pipe. The first and second test probes have the same structure and are symmetrically arranged on both sides of the connecting body. The test ends of the first and second test probes have opposite polarities and are located inside the pipe.

[0008] Based on the above technical solution, the first test probe includes an insulating substrate, a first electrode, and an electrical wire. The first electrode is fixedly disposed at one end of the insulating substrate, and an electrical wire is disposed at the other end. The first electrode is electrically connected to the electrical wire. The insulating substrate is disposed on the connecting body, the first electrode extends into the pipe, and the electrical wire is electrically connected to the electrical property detection unit. The second test probe has the same structure as the first test probe, and the polarity of the second electrode of the second test probe is opposite to that of the first electrode.

[0009] Based on the above technical solution, the first test probe also includes a sealing element, which is sleeved on the insulating substrate and pressed between the insulating substrate and the pipe.

[0010] Based on the above technical solution, the adjustment range of the first electrode along the pipe diameter direction is 0-30%, and the adjustment range of the second electrode along the pipe diameter direction is 5-35%.

[0011] Based on the above technical solution, the electrical property detection unit is configured as an LCR bridge, and the LCR bridge is electrically connected to both the first electrode and the second electrode.

[0012] Based on the above technical solution, the temperature and pressure testing unit is configured as a temperature sensor and a pressure sensor, and the differential pressure testing unit is configured as a differential pressure sensor. The temperature sensor, pressure sensor and differential pressure sensor are all installed on the pipeline.

[0013] Based on the above technical solution, the connecting body is made of PEEK insulating material, and the first electrode and the wire are both made of copper.

[0014] Based on the above technical solution, the first test probe and the second test probe are both connected to the connecting body by threads, and the first electrode, the wire and the insulating base are all fixed by silicone rubber bonding.

[0015] On the other hand, a method for monitoring the formation of natural gas hydrates using an electrical method is provided, which includes the following steps using the above-mentioned experimental apparatus for monitoring the formation of natural gas hydrates using an electrical method:

[0016] Step 1: Setting up the hydrate formation monitoring unit; Place the connecting body onto the pipe, install the first test probe and the second test probe on both sides of the pipe, and adjust the first electrode and the second electrode to the appropriate positions inside the pipe;

[0017] Step 2: Connect the electrical property detection unit; clamp the wires of the electrical property detection unit, i.e., the LCR bridge, onto the wires of the first and second test probes. The first and second electrodes fully receive and emit electrons, and in conjunction with the hydrate formation monitoring unit, obtain the values ​​of the electrical properties inside the pipeline, i.e., resistance and capacitance.

[0018] Step 3: Connect the temperature and pressure detection unit and the differential pressure detection unit; a three-way valve is connected to the test section of the pipeline, and a temperature sensor, a pressure sensor and a differential pressure sensor are connected to it respectively to measure the temperature and pressure values ​​at the test point in the pipeline, as well as the pressure difference between the two ends of the test section of the pipeline.

[0019] Step 4: Data Acquisition and Processing; The data obtained in Steps 2 and 3 are collected by the data acquisition unit and transmitted to the data processing unit for calculation and processing. The data processing unit calculates the temperature and pressure difference at a certain point in the pipeline, the pressure difference between the two ends of the pipeline, and combines the changing trends of resistance and capacitance values ​​to determine whether hydrates are formed. Specifically, if the temperature rises, the pressure decreases, the pressure difference increases, and the resistance increases while the capacitance decreases; or if the temperature remains constant, the pressure decreases, the pressure difference increases, and the resistance increases while the capacitance decreases; or if the temperature rises, the pressure remains constant, the pressure difference remains constant, and the resistance increases while the capacitance decreases; or if the temperature rises, the pressure remains constant, the pressure difference remains constant, and the resistance increases while the capacitance decreases; or if the temperature remains constant, the pressure decreases, the pressure difference remains constant, and the resistance increases while the capacitance decreases; or if the temperature remains constant, the pressure remains constant, the pressure difference increases, and the resistance increases while the capacitance decreases; or if the temperature remains constant, the pressure remains constant, the pressure difference remains constant, and the resistance increases while the capacitance decreases; then it indicates that hydrates are formed.

[0020] The beneficial effects of the technical solution provided by this invention are as follows:

[0021] This invention employs an electrical method to measure and monitor the electrical properties of a cross-section within a pipeline between two electrodes. Specifically, the resistance and capacitance of the liquid within the pipeline are monitored using a test probe in the hydrate formation monitoring unit, and numerical measurements are displayed using an LCR bridge in the electrical property detection unit. Simultaneously, the temperature, pressure, and differential pressure measured and their changing patterns are analyzed by the pipeline temperature and pressure detection unit and the differential pressure detection unit to determine whether hydrate formation has occurred within the pipeline. The overall monitoring system is easy to assemble, the testing method is simple and easy to operate, and the equipment and labor costs are low. Furthermore, it does not require sampling and has been validated in the laboratory, demonstrating high accuracy and reliable monitoring results. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0023] Figure 2 This is a flowchart illustrating the present invention;

[0024] Figure 3 This is a schematic diagram of the structure of the first test probe in this invention;

[0025] Figure 4 This is a schematic diagram of the structure of the pipe, the first test probe, and the second test probe in this invention;

[0026] Figure 5 This is a schematic diagram of the loop device in this invention;

[0027] Figure 6 This is the curve showing the change in electrical properties and hydrate volume fraction in Example 2 of the present invention;

[0028] Figure 7 This is the curve showing the change in electrical properties and hydrate volume fraction in Example 3 of the present invention; Detailed Implementation

[0029] The present invention will be further described below with reference to the accompanying drawings and embodiments:

[0030] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0031] In the description of this invention, it should be understood that the terms "left", "right", "front", "rear", "top", "bottom", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0032] like Figures 1 to 4 As shown, an experimental device for monitoring the formation of natural gas hydrates using electrical methods includes a pipeline 1, a hydrate formation monitoring unit for tracking changes in electrical properties within the pipeline 1, an electrical property detection unit for detecting changes in electrical properties within the pipeline 1, a temperature and pressure detection unit for detecting temperature and pressure changes at a certain point within the pipeline 1, a pressure difference detection unit for detecting pressure differences within the pipeline 1, a data acquisition unit for collecting data from the electrical property detection unit, the temperature and pressure detection unit, and the pressure difference detection unit, and a data processing unit for processing the data from the data acquisition unit to determine whether hydrates are forming online in the pipeline.

[0033] This invention employs an electrical method to measure and monitor the electrical properties of a cross-section within a pipeline between two electrodes. Specifically, the resistance and capacitance of the liquid within the pipeline are monitored using a test probe in the hydrate formation monitoring unit, and numerical measurements are displayed using an LCR bridge in the electrical property detection unit. Simultaneously, the temperature, pressure, and differential pressure measured and their changing patterns are analyzed by the pipeline temperature and pressure detection unit and the differential pressure detection unit to determine whether hydrate formation has occurred within the pipeline. The overall monitoring system is easy to assemble, the testing method is simple and easy to operate, and the equipment and labor costs are low. Furthermore, it does not require sampling and has been validated in the laboratory, demonstrating high accuracy and reliable monitoring results.

[0034] Based on the above technical solution, the hydrate formation monitoring unit includes a connecting body 2, a first test probe 3, and a second test probe 4. The connecting body 2 is sleeved on the pipeline 1. The first test probe 3 and the second test probe 4 have the same structure and are symmetrically arranged on both sides of the connecting body 2. The test ends of the first test probe 3 and the second test probe 4 have opposite polarities, and the test ends are located inside the pipeline 1. More preferably, the connecting body 2 and the pipeline 1 have a pressure-bearing capacity of more than 10 MPa and also possess certain corrosion resistance. Hydrates are ice-like crystalline substances formed by gas and water under high pressure and low temperature conditions. In actual pipelines, high-pressure environments are easily achieved, therefore the pressure-bearing capacity of the monitoring system must be guaranteed. In the entire oil and gas industry, additives are an indispensable part of oil and gas production. Demulsifiers, hydrate inhibitors, wax inhibitors, etc., all place higher demands on the corrosion resistance of oil and gas production equipment and pipeline devices, especially in the high-salinity seawater environment of marine oil and gas gathering and transportation pipelines.

[0035] Based on the above technical solutions, such as Figure 3 As shown, the first test probe 3 includes an insulating substrate 31, a first electrode 32, and a wire 33. The first electrode 32 is fixedly disposed at one end of the insulating substrate 31, and the wire 33 is disposed at the other end. The first electrode 32 and the wire 33 are electrically connected. The insulating substrate 31 is disposed on the connecting body 2. The first electrode 32 extends into the pipe 1, and the wire 33 is electrically connected to the electrical property detection unit. The second test probe 4 has the same structure as the first test probe 3, but the polarity of the second electrode 42 of the second test probe 4 is opposite to that of the first electrode 31. Specifically, the first test probe 3 and the second test probe 4 are disposed on both sides of the pipe 1. The testing end of the first test probe 3 is the first electrode 32, and the testing end of the second test probe 4 is the second electrode 42. The polarities of the first electrode 32 and the second electrode 42 are opposite; that is, the electrode on one side of the pipe 1 is set as the anode, and the electrode on the other side is set as the cathode. The cathode and anode are disposed opposite each other inside the pipe 1 for receiving and emitting electrons.

[0036] Based on the above technical solution, the first test probe 3 further includes a sealing element 34, which is sleeved on the insulating substrate 31 and pressed between the insulating substrate 31 and the pipe 1. More preferably, the sealing element 34 is configured as a sealing ring, which is pressed between the insulating substrate 31 and the pipe wall of the pipe 1 when the electrode is inserted into the pipe 1. It is understood that the second test probe 4 has the same sealing element structure.

[0037] Based on the above technical solutions, such as Figure 4 As shown, the adjustment range of the first electrode 32 along the diameter of pipe 1 is 0-30%, and the adjustment range of the second electrode 42 along the diameter of pipe 1 is 5-35%. It should be noted that the aforementioned adjustment range refers to the position of the end of the first electrode 32 or the end of the second electrode 42 along the diameter of pipe 1 on a certain cross-section of pipe 1. For example, the first electrode 32 is positioned at the bottom of pipe 1, i.e., at 0% of the diameter of pipe 1, and the second electrode 42 is correspondingly positioned at 5% of the diameter of pipe 1.

[0038] Based on the above technical solution, the electrical property detection unit is configured as an LCR bridge 5, which is electrically connected to both the first electrode 32 and the second electrode 42. The clamps of the LCR bridge 5 are attached to the electrical leads of the first test probe 3 and the second test probe 4. The LCR bridge 5 satisfies a resistance measurement range of 10 ohms. -3 Ω-10 3 MΩ, capacitance measurement range is 10 -3 pF-10 3μF.

[0039] Based on the above technical solution, the temperature and pressure testing unit is configured with a temperature sensor and a pressure sensor, and the differential pressure testing unit is configured with a differential pressure sensor. All three sensors are installed on the pipeline. Specifically, the temperature and pressure sensors are connected to pipeline 1 via a three-way valve to measure the temperature and pressure at a certain cross-section of pipeline 1. The differential pressure sensor is used by introducing a 3mm pipeline into its L and H ports to measure the pressure difference between the two cross-sections of pipeline 1.

[0040] Based on the above technical solution, the connecting body 2 is made of PEEK insulating material, and the first electrode 32 and the conductor 33 are both made of copper. PEEK material refers to polyetheretherketone (PEEK), and the connecting body 2 is made of this material, which has good pressure resistance and insulation properties, and does not affect the accurate measurement of electrical parameters. The first electrode 32 or the second electrode 42 is set as a copper metal ring, and the conductive part of the conductor 33, which is fixedly sleeved on the end of the insulating base 31, is made of copper. Preferably, the conductor 33 is insulated with a polyesterimide varnish layer to ensure the integrity of the system, reduce the possible influence of external conductive materials and equipment on the system, and greatly ensure the accuracy of the electrical parameters in the system, namely resistance and capacitance values. It is understood that this excludes parts that need to be conductive, such as the clamps of the LCR bridge 5, which are clamped at the copper conductors without insulation.

[0041] Based on the above technical solution, both the first test probe 3 and the second test probe 4 are connected to the connecting body 2 via threads, and the first electrode 32, the wire 33, and the insulating base 31 are all fixed by silicone rubber bonding. By threading the test probes onto the connecting body 2, the sealing ring provides pressure resistance, making installation and disassembly more convenient and operation simpler.

[0042] A method for monitoring the formation of natural gas hydrates using an electrical method, employing the aforementioned experimental apparatus for monitoring the formation of natural gas hydrates using an electrical method, includes the following steps:

[0043] Step 1: Setting up the hydrate formation monitoring unit; Install the connecting body 2 on the pipe 1, install the first test probe 3 and the second test probe 4 on both sides of the pipe 1, and adjust the first electrode 32 and the second electrode 42 to the appropriate positions inside the pipe 1;

[0044] Specifically, the first electrode 32 and the second electrode 42 are positioned at appropriate locations on a certain cross section within the pipe 1. That is, the adjustment range of the first electrode 32 along the diameter direction of the pipe 1 is 0-30%, and the adjustment range of the second electrode 42 along the diameter direction of the pipe 1 is 5-35%. For example, the first electrode 32 is set at the bottom of the pipe 1, i.e., at 0% of the pipe diameter, and the second electrode 42 is correspondingly set at 5% of the pipe diameter.

[0045] Step 2: Connect the electrical property detection unit; clamp the wires of the electrical property detection unit, i.e., the LCR bridge 5, onto the wires of the first test probe 3 and the second test probe 4, and fully receive and emit electrons through the first electrode 32 and the second electrode 42, in conjunction with the hydrate formation monitoring unit, to obtain the values ​​of the electrical properties inside the pipe 1;

[0046] Specifically, the electrical property data of the pipeline 1 is obtained by the cooperation of the electrical property detection unit and the hydrate formation monitoring unit; that is, the LCR bridge 5 is turned on, the C / R mode is adjusted, and the RS-232C serial interface is turned on, so that the anode and cathode of the test probe on both sides can fully receive and emit electrons, thereby obtaining the electrical property values ​​of resistance and capacitance in the reactor unit inside the pipeline 1.

[0047] Step 3: Connect the temperature and pressure detection unit and the differential pressure detection unit; A three-way valve is connected to the test section on pipe 1, and a temperature sensor, a pressure sensor and a differential pressure sensor are connected to it respectively to measure the temperature and pressure values ​​at the test point in pipe 1, as well as the pressure difference between the two ends of the test section of pipe 1.

[0048] Step 4: Data Acquisition and Processing; The data obtained in Steps 2 and 3 are collected by the data acquisition unit and transmitted to the data processing unit for calculation and processing; The data processing unit calculates the temperature and pressure difference at a certain point in pipe 1, the pressure difference between the two ends of the pipe, and combines the changing trends of resistance and capacitance values ​​to determine whether hydrates are formed; Specifically, if the temperature rises, the pressure decreases, the pressure difference increases, and the resistance increases, and the capacitance decreases; or if the temperature remains unchanged, the pressure decreases, the pressure difference increases, and the resistance increases, and the capacitance decreases; or if the temperature rises, the pressure remains unchanged, the pressure difference remains unchanged, and the resistance increases, and the capacitance decreases; or if the temperature rises, the pressure decreases, the pressure difference remains unchanged, and the resistance increases, and the capacitance decreases; or if the temperature remains unchanged, the pressure decreases, the pressure difference remains unchanged, and the resistance increases, and the capacitance decreases; or if the temperature remains unchanged, the pressure remains unchanged, the pressure difference increases, and the resistance increases, and the capacitance decreases; or if the temperature remains unchanged, the pressure remains unchanged, the pressure difference remains unchanged, and the resistance increases, and the capacitance decreases; then it indicates that hydrates are formed.

[0049] Example 2

[0050] This embodiment provides a test apparatus for monitoring the formation of natural gas hydrates using electrical methods, and details the process of detecting hydrates under high water content:

[0051] This device is a laboratory simulation of a high-pressure loop system for oil and gas gathering and transportation pipelines, such as... Figure 5 As shown, where Figure 5 In the diagram, LP stands for injection pump, VP for vacuum pump, SF for vacuum tank, GP for circulation pump, DP for differential pressure sensor, PR for pressure sensor, and TR for temperature sensor.

[0052] The gas used in the experiment consisted of 85% CH4 and 15% C3H8, the aqueous solution was 1 wt.% NaCl solution, and the oil was No. 5 white oil. This experiment simulated the flow conditions in an oil and gas gathering and transportation pipeline under high water content and investigated the changing trends of the electrical properties of hydrate formation, namely resistance and capacitance. Specific curves are shown below. Figure 6 As shown in the figure, the unit for hydrate volume fraction is %, the unit for capacitance is pF, and the unit for resistance is Ω.

[0053] First, the main body is fitted onto the pipe, and the first and second test probes are installed on both sides of the pipe. The first and second electrodes are adjusted to 15% and 11.7% of the pipe cross-section, respectively. Then, an airtightness test of no less than 3 MPa is performed. After the airtightness test is completed, the loop device is evacuated. Then, the pre-prepared oil-water emulsion, which has been mixed with a magnetic stirrer, is injected into the loop device through vacuum pressure and a hand-cranked injection pump. In this experiment, the mixture is 80% water and 5% oil. The gas used in the experiment, consisting of 85% CH4 and 15% C3H8, is injected into the loop device through gas cylinder 6 and the gas injection line. Then, the three-way valve 7 is adjusted to the loop flow position, and the pump is turned on to 40 Hz. After the mixture is uniform and the pressure does not drop, the three-way valve 7 is adjusted to the air inlet position to replenish the experimental device. This process is repeated until the expected loop flow pressure is reached. Then, the pump is adjusted to the experimental set speed, which is 10 Hz in this experiment.

[0054] Next, clamp the LCR bridge wire clip onto the copper wire of the test probe without insulating varnish, turn on the LCR bridge, adjust it to C / R mode, then turn on the RS-232C serial interface, turn on the cooling air bath 8, and adjust its rated temperature to 0℃.

[0055] As the volume fraction of hydrates increases and hydrates form, the system exhibits a trend of increasing resistance and decreasing capacitance. For example, Figure 6 As shown, Figure 6The rapid hydrate formation stage from 120 to 140 minutes is shown. It is clearly visible that during this period, as the hydrate volume fraction increases sharply, the pressure differential fluctuation increases dramatically, and the resistivity increases significantly while the capacitance decreases. In the stable flow stage of the hydrate slurry, the pressure differential fluctuation is smaller and almost unchanged, but the trend of increasing resistivity and decreasing capacitance is still clearly visible as the hydrate volume fraction increases.

[0056] Example 3

[0057] This embodiment provides a test apparatus for monitoring the formation of natural gas hydrates using electrical methods, and details the process of monitoring hydrates in partially dispersed systems:

[0058] The liquid phase contents in this experiment were: 50% water and 35% oil. This apparatus is a laboratory simulation of a high-pressure loop device for oil and gas gathering and transportation pipelines. Figure 5 As shown, where Figure 5 In the diagram, LP stands for injection pump, VP for vacuum pump, SF for vacuum tank, GP for circulation pump, DP for differential pressure sensor, PR for pressure sensor, and TR for temperature sensor. The gas used in the experiment consisted of 85% CH4 and 15% C3H8, the aqueous solution was 1 wt.% NaCl solution, and the oil was No. 5 white oil. This experiment simulated the flow conditions of an oil and gas gathering and transportation pipeline in a partially dispersed system and investigated the changing trends of the electrical properties of hydrate formation, namely resistance and capacitance. Specific curves are shown below. Figure 7 As shown in the figure, the unit for hydrate volume fraction is %, the unit for capacitance is pF, and the unit for resistance is Ω.

[0059] First, the main body is fitted onto the pipe, and the first and second test probes are installed on both sides of the pipe. The first and second electrodes are adjusted to 10% and 6.7% of the pipe cross-section, respectively. Then, an airtightness test of no less than 3 MPa is performed. After the airtightness test is completed, the loop device is evacuated. Then, the pre-prepared oil-water emulsion, which has been mixed with a magnetic stirrer, is injected into the loop device through vacuum pressure and a hand-cranked injection pump. The gas used in the experiment, consisting of 85% CH4 and 15% C3H8, is injected into the loop device through gas cylinder 6 and the gas injection line. Then, the three-way valve 7 is adjusted to the loop flow position, and the pump is turned on to 40 Hz. After the mixture is uniform and the pressure does not drop, the three-way valve 7 is adjusted to the gas inlet position to replenish the experimental device. This process is repeated until the expected loop flow pressure is reached. Then, the pump is adjusted to the experimental set speed, which is 20 Hz in this experiment.

[0060] Next, clamp the LCR bridge wire clip onto the copper wire of the test probe without insulating varnish, turn on the LCR bridge, adjust it to C / R mode, then turn on the RS-232C serial interface, turn on the cooling air bath 8, and adjust its rated temperature to 0℃.

[0061] As the volume fraction of hydrates increases and hydrates are formed, the system exhibits a trend of increasing resistance and decreasing capacitance. For example... Figure 7 As shown, Figure 7 The diagram illustrates the rapid hydrate formation stage from 70 to 90 minutes. It clearly shows that during this period, as the hydrate volume fraction increases dramatically, the pressure differential fluctuations increase, and the resistivity and capacitance decrease significantly. In the stable flow stage of the hydrate slurry, the pressure differential fluctuations are smaller and almost unchanged; however, with the increase of the hydrate volume fraction, the trends of increasing resistivity and decreasing capacitance are still clearly visible.

[0062] The foregoing has shown and described the basic principles and main features of the present invention. It will be apparent to those skilled in the art that the present invention is not limited to the details of the above exemplary embodiments. Therefore, the embodiments should be considered as exemplary and not restrictive. The scope of the present invention is defined by the appended claims rather than the foregoing description. Therefore, it is intended that all variations falling within the meaning and scope of the equivalents of the claims be included within the present invention.

[0063] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A test apparatus for monitoring the formation of natural gas hydrates using an electrical method, characterized in that, The system includes a pipeline (1), a hydrate formation monitoring unit for tracking changes in electrical properties within the pipeline (1), an electrical property detection unit for detecting changes in electrical properties within the pipeline (1), a temperature and pressure detection unit for detecting temperature and pressure changes at a point within the pipeline (1), a pressure difference detection unit for detecting pressure differences within the pipeline (1), a data acquisition unit for collecting data from the electrical property detection unit, the temperature and pressure detection unit, and the pressure difference detection unit, and a data processing unit for processing data from the data acquisition unit to determine whether hydrates are being generated online in the pipeline; the hydrate formation monitoring unit includes a connecting body (2), a first test probe (3), and a second test probe (4). The connecting body (2) is fitted onto the pipeline (1). The first test probe (3) and the second test probe (4) have the same structure and are symmetrically arranged on both sides of the connecting body (2). The test ends of the first test probe (3) and the second test probe (4) have opposite polarities. The test ends are located inside the pipeline (1). The presence of hydrates is determined by analyzing the temperature and pressure difference at a point within the pipeline, the pressure difference between the two ends of the pipeline, and the trends in resistance and capacitance values: If the temperature rises, the pressure decreases, the pressure difference increases, and the resistance increases while the capacitance decreases; or if the temperature remains constant, the pressure decreases, the pressure difference increases, and the resistance increases while the capacitance decreases; or if the temperature rises, the pressure remains constant, the pressure difference remains constant, and the resistance increases while the capacitance decreases; or if the temperature rises, the pressure remains constant, the pressure difference remains constant, and the resistance increases while the capacitance decreases; or if the temperature remains constant, the pressure decreases, the pressure difference remains constant, and the resistance increases while the capacitance decreases; or if the temperature remains constant, the pressure remains constant, the pressure difference increases, and the resistance increases while the capacitance decreases; or if the temperature remains constant, the pressure remains constant, the pressure difference remains constant, and the resistance increases while the capacitance decreases; then hydrates are present.

2. The experimental apparatus for monitoring the formation of natural gas hydrates using an electrical method according to claim 1, characterized in that, The first test probe (3) includes an insulating substrate (31), a first electrode (32), and an electrical wire (33). The first electrode (32) is fixedly disposed at one end of the insulating substrate (31), and the electrical wire (33) is disposed at the other end. The first electrode (32) and the electrical wire (33) are electrically connected. The insulating substrate (31) is disposed on the connecting body (2). The first electrode (32) extends into the pipe (1). The electrical wire (33) is electrically connected to the electrical property detection unit. The second test probe (4) has the same structure as the first test probe (3), and the polarity of the second electrode (42) of the second test probe (4) is opposite to that of the first electrode (32).

3. The experimental apparatus for monitoring the formation of natural gas hydrates using an electrical method according to claim 2, characterized in that, The first test probe (3) also includes a seal (34), which is fitted onto the insulating substrate (31) and pressed between the insulating substrate (31) and the pipe (1).

4. The experimental apparatus for monitoring the formation of natural gas hydrates using an electrical method according to claim 2, characterized in that, The adjustment range of the first electrode (32) along the diameter of the pipe (1) is 0-30%, and the adjustment range of the second electrode (42) along the diameter of the pipe (1) is 5-35%.

5. The experimental apparatus for monitoring the formation of natural gas hydrates using an electrical method according to claim 2, characterized in that, The electrical property detection unit is configured as an LCR bridge (5), and the LCR bridge (5) is electrically connected to the first electrode (32) and the second electrode (42).

6. The experimental apparatus for monitoring the formation of natural gas hydrates using an electrical method according to claim 1, characterized in that, The temperature and pressure detection unit is configured as a temperature sensor and a pressure sensor, and the differential pressure detection unit is configured as a differential pressure sensor. The temperature sensor, pressure sensor, and differential pressure sensor are all installed on the pipeline.

7. The experimental apparatus for monitoring the formation of natural gas hydrates using an electrical method according to claim 2, characterized in that, The connecting body (2) is made of PEEK insulating material, and the first electrode (32) and the wire (33) are both made of copper.

8. The experimental apparatus for monitoring the formation of natural gas hydrates using an electrical method according to claim 2, characterized in that, The first test probe (3) and the second test probe (4) are both connected to the connecting body (2) by threads, and the first electrode (32), the wire (33) and the insulating base (31) are all fixed by silicone rubber bonding.

9. A method for monitoring the formation of natural gas hydrates using electrical methods, characterized in that, The test apparatus according to claim 6 includes the following steps: Step 1: Setting up the hydrate formation monitoring unit; Place the connecting body (2) on the pipe (1), install the first test probe (3) and the second test probe (4) on both sides of the pipe (1), and adjust the first electrode (32) and the second electrode (42) to the appropriate positions inside the pipe (1); Step 2: Connect the electrical property detection unit; clamp the wire of the electrical property detection unit, i.e., the LCR bridge (5), onto the wires of the first test probe (3) and the second test probe (4), and fully receive and emit electrons through the first electrode (32) and the second electrode (42), and cooperate with the hydrate formation monitoring unit to obtain the values ​​of the electrical properties, i.e., resistance and capacitance, inside the pipe (1); Step 3: Connect the temperature and pressure detection unit and the differential pressure detection unit; A three-way valve is connected to the test section of the pipeline (1), and a temperature sensor, a pressure sensor and a differential pressure sensor are connected to it respectively to measure the temperature and pressure values ​​of the test point in the pipeline (1) and the pressure difference between the two ends of the test section of the pipeline (1); Step 4: Data Acquisition and Processing; The data obtained in Step 2 and Step 3 are collected by the data acquisition unit and sent to the data processing unit for calculation and processing; The data processing unit calculates the temperature and pressure difference at a certain point in the pipeline (1), the pressure difference at both ends of the pipeline, and judges whether hydrates are generated by combining the trend of resistance and capacitance values; Specifically, if the temperature rises, the pressure decreases, the pressure difference increases and the resistance increases and the capacitance decreases; or if the temperature remains unchanged, the pressure decreases, the pressure difference increases and the resistance increases and the capacitance decreases; or if the temperature rises, the pressure remains unchanged, the pressure difference increases and the resistance increases and the capacitance decreases; or if the temperature rises, the pressure decreases, the pressure difference remains unchanged and the resistance increases and the capacitance decreases; or if the temperature rises, the pressure remains unchanged, the pressure difference remains unchanged and the resistance increases and the capacitance decreases; or if the temperature remains unchanged, the pressure decreases, the pressure difference remains unchanged and the resistance increases and the capacitance decreases; or if the temperature remains unchanged, the pressure remains unchanged, the pressure difference remains unchanged and the resistance increases and the capacitance decreases; or if the temperature remains unchanged, the pressure remains unchanged, the pressure difference remains unchanged and the resistance increases and the capacitance decreases; then it indicates that hydrates are generated.

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