Device and method for rapidly measuring dynamic generation temperature of high-pressure hydrate

Abstract

The invention discloses a high-pressure hydrate dynamic generation temperature rapid measuring device and method, and relates to the technical field of oil and gas exploitation, the measuring device comprises a reaction kettle system, the reaction kettle system comprises a high-low temperature alternating test box adopting nonlinear cooling and a high-pressure reaction kettle located in the high-low temperature alternating test box; the stirring system is positioned in the high-low temperature alternating test box and is used for stirring the experimental fluid in the high-pressure reaction kettle in a magnetic coupling manner; the sample preparation system is used for performing sample preparation on the experiment; and the observation system is used for observing an experiment in the high-pressure reaction kettle. According to the invention, the hydrate generation temperatures of the water-producing oil-gas well and the surface pipeline under different pressures, flow rates and surface roughness can be accurately measured, and experimental data are fitted to obtain a hydrate generation empirical formula comprehensively considering the factors of pressure, fluid flow rates and surface roughness; and technical support is provided for hydrate prevention and supply conservation of oil and gas fields in winter.

Description

Technical Field

[0001] The present invention relates to the technical field of oil and gas exploitation, and more specifically to a device and method for quickly determining the dynamic generation temperature of high-pressure hydrates. Background Art

[0002] For the existing hydrate temperature measurement devices and methods, there are currently 4 experimental methods, mainly including:

[0003] 1. Observation method: The observation method uses a visual PVT instrument to measure the hydrate formation temperature at different pressures directly from the observation window through a constant pressure and temperature reduction method.

[0004] 2. Graphical method: The graphical method uses a constant volume reactor. By means of constant volume cooling, the temperature and pressure change curve of the hydrate formation process is measured by a pressure sensor to obtain the PT curve of the hydrate formation process. The hydrate formation temperature can be obtained by finding the inflection point of the PT curve.

[0005] 3. Differential Scanning Calorimetry: Differential Scanning Calorimetry uses a differential scanning calorimeter to utilize the thermal effect during the decomposition of hydrates. By measuring the heat flow during the decomposition of hydrates, the phase equilibrium conditions of hydrates are characterized, that is, the phase equilibrium curve of hydrates is obtained.

[0006] 4. Hydrate dynamic blockage experiment: Use the pressure difference before and after the capillary to determine whether hydrate is generated. When the pressure difference before and after the capillary increases sharply, it means that hydrate begins to form in large quantities, and the temperature at this time is taken as the hydrate formation temperature.

[0007] The above four experimental methods in the prior art have the following problems:

[0008] (1) Observation method: The observation method can only be carried out under static conditions, which fails to allow sufficient contact between the gas and liquid phases. It is far from the actual production conditions on site and requires a long experimental time.

[0009] (2) Graphical method: The PT curve obtained by the graphical method through constant volume cooling is not a constant pressure condition, and the hydrate production temperature obtained is not a certain pressure. It is impossible to obtain a hydrate formation temperature PT curve under any pressure.

[0010] (3) Differential scanning calorimetry: In the differential scanning calorimetry method, the sample is not allowed to stand for a period of time during the loading process, so that the gas phase is fully dissolved in the solution. At the same time, during the experiment, hydrates are preferentially formed at the gas-liquid interface, resulting in the inability of hydrates to grow further. Hydrates are in a metastable state. The temperature is increased to determine the decomposition point of the hydrate. This temperature value is not the decomposition temperature under the condition of stable existence of hydrates.

[0011] (4) Hydrate dynamic blockage experimental device: The hydrate formation temperature obtained in the dynamic blockage experiment is the temperature point at which hydrates begin to form in large quantities. There is a certain error compared with the actual hydrate formation temperature. Summary of the invention

[0012] In order to overcome the defects existing in the above-mentioned prior art, the present invention discloses a device and method for quickly determining the dynamic generation temperature of high-pressure hydrates. The purpose of the present invention is to solve the problems existing in the experimental methods in the prior art. The present invention is based on the theory of crystallization and phase state, and combined with the actual working conditions of the flow of the wellbore and the ground pipeline network, it can obtain the change of hydrate formation temperature under different influencing factors, and provide experimental data for theoretical calculations and the formulation of on-site hydrate blockage resolution plans. The experimental data are fitted to obtain a hydrate formation temperature formula that comprehensively considers the factors of pressure, fluid flow rate and surface roughness. The present invention is suitable for the experimental determination of hydrate formation temperature in water-producing gas and oil wells and ground pipelines.

[0013] In order to achieve the above objectives, the technical solution adopted by the present invention is:

[0014] In a first aspect, the present invention provides a device for quickly determining the dynamic generation temperature of high-pressure hydrates, comprising:

[0015] A reactor system, the reactor system comprising a high-low temperature alternating test box using nonlinear temperature reduction and a high-pressure reactor located in the high-low temperature alternating test box;

[0016] A stirring system, the stirring system is located in the high and low temperature alternating test box, and stirs the experimental fluid in the high-pressure reactor by means of magnetic coupling;

[0017] A sample preparation system, the sample preparation system includes a liquid sample preparation subsystem and a gas sample preparation subsystem, the liquid sample preparation subsystem and the gas sample preparation subsystem are both located outside the high and low temperature alternating test box, and are both connected to the high pressure reactor through pipelines to prepare samples for the experiment;

[0018] An observation system is located in the high and low temperature alternating test box and is used to observe the experiments inside the high-pressure reactor.

[0019] Preferably, the reactor system further comprises a top cover, a loading and unloading hole, a sealing gasket I, a pressure-resistant transparent medium, a sealing gasket II and a metal crystal block;

[0020] The high-pressure reactor is provided with an opening on the side, the top cover is screwed on the opening in a fixed connection manner through a loading and unloading hole, a visual window for observation by the observation system is provided on the top cover, the sealing gasket I, the pressure-resistant transparent medium, and the sealing gasket II are sequentially assembled in the top cover, and the metal crystal block is arranged on the pressure-resistant transparent medium and is located inside the high-pressure reactor.

[0021] Preferably, the metal crystal block is made of oil pipe or gas pipeline material, and the metal crystal block includes a plurality of metal crystal blocks with different roughness.

[0022] Preferably, the reactor system further comprises a temperature sensor, a reactor support frame, a liquid inlet stop valve IV and an air inlet stop valve IV;

[0023] The temperature sensor is arranged on the high-pressure reactor, the high-pressure reactor is assembled on the reactor support frame, the high-pressure reactor is connected with a liquid supply pipeline and an air supply pipeline, and the liquid inlet stop valve IV and the air inlet stop valve IV are respectively arranged on the liquid supply pipeline and the air supply pipeline.

[0024] Preferably, the reactor system further comprises a three-way connection, a liquid outlet stop valve, a back pressure controller and a liquid collecting bottle;

[0025] The liquid supply pipeline is connected to the liquid outlet pipeline through a tee, the liquid outlet stop valve and the back pressure controller are arranged on the liquid outlet pipeline in sequence along the fluid flow direction, and the liquid collecting bottle is arranged at the outlet of the liquid outlet pipeline.

[0026] Preferably, the stirring system comprises a stepping motor, a strong magnetic metal block I, a soft pad, a metal sealed bearing, a strong magnetic metal block II and a resin rotor;

[0027] The stepper motor is installed on the reactor support frame, and the strong magnetic metal block I is installed on the upward rotating shaft of the stepper motor; a concave hole is arranged at the bottom of the inner part of the high-pressure reactor, the soft pad is installed in the concave hole, the metal sealed bearing is installed on the soft pad in the concave hole, the strong magnetic metal block II is embedded in the center hole of the metal sealed bearing, and the resin rotor is installed on the strong magnetic metal block II;

[0028] The strong magnetic metal block I and the strong magnetic metal block II are matched, and the stepping motor drives the strong magnetic metal block I to rotate, and the strong magnetic metal block I drives the strong magnetic metal block II to rotate, and drives the resin rotor to rotate, so as to stir the experimental fluid in the high-pressure reactor.

[0029] Preferably, the liquid preparation subsystem comprises a high-pressure displacement pump I, a pressure sensor I, a liquid inlet stop valve I, a liquid inlet stop valve II, an intermediate container I and a liquid inlet stop valve III;

[0030] The high-pressure displacement pump I, liquid inlet stop valve I, liquid inlet stop valve II, intermediate container I and liquid inlet stop valve III are connected in sequence through pipelines, the pressure sensor I is installed on the pipeline between the high-pressure displacement pump I and the liquid inlet stop valve I, and the liquid inlet stop valve III is connected to the liquid inlet stop valve IV through a pipeline.

[0031] Preferably, the gas matching subsystem includes a high-pressure displacement pump II, a pressure sensor II, an air intake stop valve I, an air intake stop valve II, an intermediate container II and an air intake stop valve III;

[0032] The high-pressure displacement pump II, the air intake stop valve I, the air intake stop valve II, the intermediate container II and the air intake stop valve III are connected in sequence through pipelines, the pressure sensor II is installed on the pipeline between the high-pressure displacement pump II and the air intake stop valve I, and the air intake stop valve III is connected to the air intake stop valve IV through a pipeline.

[0033] Preferably, the observation system comprises an industrial camera and a support frame, the industrial camera is mounted on the support frame, and the camera end of the industrial camera faces the visual window of the top cover.

[0034] In a second aspect, the present invention provides a method for quickly determining the dynamic formation temperature of high-pressure hydrates, comprising the following steps:

[0035] S1: Cleaning the autoclave: using an organic solvent to clean the entire autoclave and drying it;

[0036] S2: Prepare the test sample: fill the intermediate container I with formation water, fill the intermediate container II with the test natural gas sample, and pressurize it to the test pressure P i , and keep the pressure constant;

[0037] S3: Evacuate the reactor system and connect it to the sample preparation system;

[0038] S4: Maintain pressure and transfer samples: Open the liquid inlet stop valve, use the high-pressure displacement pump I to inject the formation water in the intermediate container I into the high-pressure reactor until half of the metal crystal block is submerged, then close the liquid inlet stop valve, open the gas inlet stop valve, use the high-pressure displacement pump II to inject the natural gas in the intermediate container II into the high-pressure reactor, and pressurize it until the value of the pressure sensor II is equal to P i , the high-pressure displacement pump II stops pumping and maintains a constant pressure, and then closes the air intake stop valve;

[0039] S5: The back pressure controller loads the back pressure, making the back pressure P h Equal to the pressure P in the high pressure reactor i ;

[0040] S6: Start the high and low temperature alternating test chamber and raise the temperature of the high pressure reactor to the formation temperature T max , and keep the temperature constant;

[0041] S7: Start the stirring system, which rotates at a certain speed v to simulate the flow state of the wellbore or surface pipeline;

[0042] S8: Cooling: Use a high and low temperature alternating test chamber to cool in a nonlinear way;

[0043] S9: Observation: Start the industrial camera and record the real-time temperature T;

[0044] S10: Formation temperature verification: Review the images recorded by the industrial camera to find the temperature T when hydrates first form. i ;

[0045] S11: Turn off the stirring system and the high and low temperature alternating test chamber, and use the back pressure controller to reduce the back pressure P h , making it slightly lower than the experimental test pressure P i , open the liquid inlet stop valve IV and the liquid outlet stop valve, release all the experimental fluid in the high-pressure reactor into the liquid collection bottle, close the liquid outlet stop valve, and then use the back pressure controller to increase the back pressure to P h To a pressure slightly higher than the pressure Pi in the autoclave;

[0046] S12: Disassemble the reactor system and sample preparation system; clean the high-pressure reactor and change the experimental pressure P i , repeat S2 to S12;

[0047] S13: Plotting the generation temperature T i With pressure P i The change curve.

[0048] Preferably, it also includes:

[0049] S14: Change the speed v of the stepper motor, repeat S2 to S13, different speed v i The generation temperature T i With pressure P i The change curve.

[0050] Preferably, it also includes:

[0051] S15: Change the roughness μ of the metal crystal block, repeat S2 to S13, different roughness μ i The generation temperature T i With pressure P i The change curve.

[0052] Preferably, it also includes:

[0053] S16: Fit the experimental data to obtain an empirical formula for hydrate formation temperature that comprehensively considers pressure, fluid flow rate, and surface roughness factors.

[0054] Preferably, the temperature empirical formula is:

[0055] T i =A(P i ) D ×B(v i ) E×C(μ i ) F

[0056] Where, T i is the temperature when hydrate is formed, °C; v i is the speed, r / min; μ i is the surface roughness, dimensionless; A, B, C, D, E, and F are all constants.

[0057] The main innovative features of the present invention include the following four points:

[0058] (1) Consider the factors affecting hydrate formation temperature as much as possible

[0059] Based on the reactor and reactor system, the influence of pressure and surface roughness on hydrate formation temperature can be considered. Based on the stirring system, the influence of fluid flow rate on hydrate formation temperature can be considered.

[0060] (2) Create dynamic experimental conditions to solve sealing problems

[0061] The magnetic coupling principle is adopted, and an external stepper motor is used to drive the rotation of a strong magnetic metal block, so that the resin rotor can rotate almost unimpeded together with the metal sealed bearing, thereby shearing and stirring the experimental fluid and simulating the flow of fluid in a wellbore or ground pipe network. The stepper motor is located outside the reactor, and the rotation of a strong magnet is used to rotate the resin rotor. In the past, high-pressure stirring devices used a method of drilling holes on the reactor, allowing the rotor of the motor to pass through the holes, and placing a sealing rubber ring in the hole to achieve dynamic simulation and sealing. However, this method will cause the sealing rubber ring to wear and cause seal failure. The stirring system used in the present invention can not only perform dynamic experiments, but also avoid the occurrence of seal failure.

[0062] (3) Create conditions for rapid generation

[0063] The metal crystal block made of oil pipe or gas pipeline material has a rough surface, which can provide crystal nuclei for the formation of hydrates, allowing the hydrate crystals to grow rapidly and shorten the experimental time.

[0064] (4) Nonlinear cooling

[0065] The use of a high and low temperature alternating test chamber with a nonlinear cooling method can effectively avoid the phenomenon that the hydrate formation temperature has been reached but no hydrate is formed due to continuous cooling, thereby achieving the purpose of accurately determining the hydrate formation temperature.

[0066] The key improvements of the present invention are:

[0067] The present invention comprehensively considers the factors that affect hydrate formation, and establishes a dynamic hydrate formation temperature experimental measurement device that can simultaneously consider pressure, surface roughness, and fluid flow rate. It overcomes the shortcomings of existing experimental devices that do not consider comprehensive factors and are inconsistent with the actual wellbore and ground pipelines. The purpose of dynamic hydrate formation temperature testing under pressure conditions is achieved. The stirring system designed based on the magnetic coupling principle of the present invention can produce a flow state while avoiding the sealing problems of traditional agitators. The metal crystal block designed based on the crystallization theory of the present invention can provide crystal nuclei for hydrate formation and simulate the materials of the wellbore and ground pipelines to achieve rapid hydrate formation and shorten the experimental time. The nonlinear cooling method is adopted to avoid the phenomenon that the hydrate formation temperature has been reached but not generated due to continuous cooling in the past, so as to achieve the purpose of accurately measuring the hydrate formation temperature.

[0068] Beneficial effects of the present invention:

[0069] (1) The present invention can accurately measure the hydrate formation temperature of water-producing oil and gas wells and ground pipelines under different pressures, flow rates and surface roughnesses, fit the experimental data, and obtain an empirical formula for hydrate formation that comprehensively considers the factors of pressure, fluid flow rate and surface roughness, which is more effective in guiding field production.

[0070] (2) The stirring system designed based on the magnetic coupling principle of the present invention can carry out dynamic experiments and also avoid the occurrence of sealing failure.

[0071] (3) The metal crystal block of the present invention can provide crystal nuclei for hydrate formation and simulate the material of the wellbore and the surface pipeline to achieve rapid hydrate formation and shorten the experimental time.

[0072] (4) The present invention adopts a nonlinear cooling method to avoid the phenomenon that the hydrate formation temperature is reached but no hydrate is formed due to continuous cooling in the past, thereby achieving the purpose of accurately determining the hydrate formation temperature. BRIEF DESCRIPTION OF THE DRAWINGS

[0073] Figure 1 This is a schematic diagram of a device for quickly measuring the dynamic generation temperature of high-pressure hydrates according to the present invention;

[0074] Figure 2 It is a front view of the top cover of the present invention;

[0075] Figure 3 This is a top view of the top cover of the present invention;

[0076] Figure 4 It is a schematic diagram of the pressure-resistant transparent medium and the metal crystal block of the present invention;

[0077] Figure 5 A temperature curve diagram for hydrate generation according to an embodiment of the present invention;

[0078] Reference numerals:

[0079] 1. Temperature sensor; 2. High and low temperature alternating test chamber; 3. High pressure reactor; 4. Top cover; 5. Loading and unloading hole; 6. Industrial camera; 7. Support frame; 8. Sealing gasket Ⅰ; 9. Pressure-resistant transparent medium; 10. Metal crystal block; 11. Reactor support frame; 12. Strong magnetic metal block Ⅰ; 13. Stepper motor; 14. Liquid collecting bottle; 15. Back pressure controller; 16. Liquid outlet stop valve; 17. Tee; 18. Liquid inlet stop valve Ⅲ; 19. Intermediate container Ⅰ; 20 , liquid inlet stop valve II; 21. liquid inlet stop valve I; 22. pressure sensor I; 23. high-pressure displacement pump I; 24. air inlet stop valve I; 25. high-pressure displacement pump II; 26. pressure sensor II; 27. air inlet stop valve II; 28. intermediate container II; 29. ​​air inlet stop valve III; 30. liquid inlet stop valve IV; 31. metal sealed bearing; 32. strong magnetic metal block II; 33. air inlet stop valve IV; 34. resin rotor; 35. soft pad; 36. sealing gasket II. DETAILED DESCRIPTION

[0080] The concept, specific structure and technical effects of the present invention will be clearly and completely described below in conjunction with the embodiments and drawings to fully understand the purpose, characteristics and effects of the present invention.

[0081] Example 1

[0082] A device for quickly measuring the dynamic formation temperature of high-pressure hydrates, such as Figure 1 As shown, including:

[0083] A reactor system, the reactor system includes a high-low temperature alternating test box 2 using nonlinear temperature reduction and a high-pressure reactor 3 located in the high-low temperature alternating test box 2;

[0084] A stirring system, which is located in the high-low temperature alternating test box 2 and uses magnetic coupling to stir the experimental fluid in the high-pressure reactor 3;

[0085] The sample preparation system includes a liquid sample preparation subsystem and a gas sample preparation subsystem. Both the liquid sample preparation subsystem and the gas sample preparation subsystem are located outside the high and low temperature alternating test box 2 and are connected to the high pressure reactor 3 through pipelines to prepare samples for the experiment;

[0086] The observation system is located in the high and low temperature alternating test box 2 and is used to observe the experiments inside the high-pressure reactor 3 .

[0087] In this embodiment, the high and low temperature alternating test box adopts a nonlinear cooling method, which can effectively avoid the phenomenon that the hydrate formation temperature has been reached but hydrates are not formed due to continuous cooling. The stirring system adopts a magnetic coupling method to stir the experimental fluid in the high-pressure reactor 3, avoiding the occurrence of sealing failure.

[0088] like Figure 1 , 2 As shown in , 3 and 4, the reactor system also includes a top cover 4, a loading and unloading hole 5, a sealing gasket I 8, a pressure-resistant transparent medium 9, a sealing gasket II 36 and a metal crystal block 10;

[0089] An opening is provided on the side of the high-pressure reactor 3, and a top cover 4 is screwed on the opening in a fixed connection manner through a loading and unloading hole 5. A visual window for observation by an observation system is provided on the top cover 4. A sealing gasket I8, a pressure-resistant transparent medium 9, and a sealing gasket II36 are sequentially assembled in the top cover 4. A metal crystal block 10 is arranged on the pressure-resistant transparent medium 9 and is located inside the high-pressure reactor 3.

[0090] In this embodiment, the metal crystal block 10 is made of oil pipe or gas pipeline material, and the metal crystal block 10 includes a plurality of metal crystal blocks with different roughness. The metal crystal block 10 made of oil pipe or gas pipeline material has a rough surface, which can provide crystal nuclei for the formation of hydrates, so that the hydrate crystals can grow quickly, shortening the experimental time.

[0091] like Figure 1 As shown, the reactor system also includes a temperature sensor 1, a reactor support frame 11, a liquid inlet stop valve IV30 and an air inlet stop valve IV33;

[0092] The temperature sensor 1 is arranged on the high-pressure reactor 3 for measuring the internal temperature of the high-pressure reactor 3. The high-pressure reactor 3 is assembled on the reactor support frame 11. The high-pressure reactor 3 is connected with a liquid supply pipeline and a gas supply pipeline. The liquid inlet stop valve IV30 and the gas inlet stop valve IV33 are respectively arranged on the liquid supply pipeline and the gas supply pipeline.

[0093] like Figure 1 As shown, the reactor system also includes a three-way connection 17, a liquid outlet stop valve 16, a back pressure controller 15 and a liquid collecting bottle 14; the liquid supply pipeline is connected to the liquid outlet pipeline through the three-way connection 17, the liquid outlet stop valve 16 and the back pressure controller 15 are sequentially arranged on the liquid outlet pipeline along the fluid flow direction, and the liquid collecting bottle 14 is arranged at the outlet of the liquid outlet pipeline. By setting the above structure, the high-pressure reactor 3 is convenient for draining liquid and controlling the back pressure.

[0094] like Figure 1 As shown, the stirring system includes a stepping motor 13, a strong magnetic metal block I 12, a soft pad 35, a metal sealing bearing 31, a strong magnetic metal block II 32 and a resin rotor 34;

[0095] The stepper motor 13 is mounted on the reactor support frame 11, and the strong magnetic metal block I 12 is mounted on the upward rotating shaft of the stepper motor 13; a concave hole is provided at the bottom of the high-pressure reactor 3, a soft pad 35 is assembled in the concave hole, a metal sealing bearing 31 is assembled on the soft pad 35 in the concave hole, a strong magnetic metal block II 32 is embedded in the center hole of the metal sealing bearing 31, and a resin rotor 34 is mounted on the strong magnetic metal block II 32;

[0096] The strong magnetic metal block I12 and the strong magnetic metal block II32 are matched, and the stepper motor 13 drives the strong magnetic metal block I12 to rotate, and the strong magnetic metal block I12 drives the strong magnetic metal block II32 to rotate, and drives the resin rotor 34 to rotate, so as to stir the experimental fluid in the high-pressure reactor 3. The magnetic coupling principle is adopted, and the rotation of the strong magnetic metal block is driven by an external stepper motor, so that the resin rotor can rotate with the metal sealed bearing approximately without resistance, thereby shearing and stirring the experimental fluid, simulating the flow of the fluid in the wellbore or the ground pipe network.

[0097] like Figure 1 As shown, the liquid preparation subsystem includes a high-pressure displacement pump Ⅰ23, a pressure sensor Ⅰ22, a liquid inlet stop valve Ⅰ21, a liquid inlet stop valve Ⅱ20, an intermediate container Ⅰ19 and a liquid inlet stop valve Ⅲ18;

[0098] The high-pressure displacement pump I23, the liquid inlet stop valve I21, the liquid inlet stop valve II20, the intermediate container I19 and the liquid inlet stop valve III18 are connected in sequence through pipelines, the pressure sensor I22 is installed on the pipeline between the high-pressure displacement pump I23 and the liquid inlet stop valve I21, and the liquid inlet stop valve III18 is connected to the liquid inlet stop valve IV30 through a pipeline. By setting the above structure, it is convenient to prepare liquid samples for the high-pressure reactor 3.

[0099] like Figure 1 As shown, the gas matching subsystem includes a high-pressure displacement pump II 25, a pressure sensor II 26, an air intake stop valve I 24, an air intake stop valve II 27, an intermediate container II 28 and an air intake stop valve III 29;

[0100] The high-pressure displacement pump II 25, the air intake stop valve I 24, the air intake stop valve II 27, the intermediate container II 28 and the air intake stop valve III 29 are connected in sequence through pipelines, the pressure sensor II 26 is installed on the pipeline between the high-pressure displacement pump II 25 and the air intake stop valve I 24, and the air intake stop valve III 29 is connected to the air intake stop valve IV 33 through a pipeline. By setting the above structure, it is convenient to perform gas sampling on the high-pressure reactor 3.

[0101] like Figure 1 As shown, the observation system includes an industrial camera 6 and a support frame 7. The industrial camera 6 is mounted on the support frame 7. The camera end of the industrial camera 6 faces the visible window of the top cover 4 to capture the experimental conditions inside the high-pressure reactor 3.

[0102] Example 2

[0103] A method for quickly determining the dynamic formation temperature of high-pressure hydrates comprises the following steps:

[0104] S1: cleaning the autoclave 3: cleaning the entire autoclave 3 with an organic solvent and drying it;

[0105] S2: Prepare the test sample: fill the intermediate container I 19 with formation water, fill the intermediate container II 28 with the test natural gas sample, and pressurize it to the test pressure P i , and keep the pressure constant;

[0106] S3: Evacuate the reactor system and connect it to the sample preparation system;

[0107] S4: Maintain pressure and transfer sample: Open the liquid inlet stop valve, use the high-pressure displacement pump I23 to inject the formation water in the intermediate container I19 into the high-pressure reactor 3 until half of the metal crystal block 10 is submerged, then close the liquid inlet stop valve, open the gas inlet stop valve, use the high-pressure displacement pump II25 to inject the natural gas in the intermediate container II28 into the high-pressure reactor 3, and pressurize it until the value of the pressure sensor II26 is equal to P i , the high-pressure displacement pump II 25 stops pumping and maintains constant pressure, and then closes the air intake stop valve;

[0108] S5: The back pressure controller 15 loads the back pressure so that the back pressure P h Equal to the pressure P in the high pressure reactor 3 i ;

[0109] S6: Start the high and low temperature alternating test box 2 to raise the temperature of the high pressure reactor 3 to the formation temperature T max , and keep the temperature constant;

[0110] S7: Start the stirring system, which rotates at a certain speed v to simulate the flow state of the wellbore or surface pipeline;

[0111] S8: Cooling: using the high and low temperature alternating test chamber 2 to cool in a nonlinear way;

[0112] S9: Observation: Start the industrial camera 6 and record the real-time temperature T;

[0113] S10: Formation temperature verification: Review the images recorded by the industrial camera 6 to find the temperature T when the hydrate starts to form. i ;

[0114] S11: Turn off the stirring system and the high and low temperature alternating test chamber 2, and use the back pressure controller 15 to reduce the back pressure P h , making it slightly lower than the experimental test pressure P i, open the liquid inlet stop valve IV30 and the liquid outlet stop valve 16, release all the experimental fluid in the high-pressure reactor 3 into the liquid collecting bottle 14, close the liquid outlet stop valve 16, and then use the back pressure controller 15 to increase the back pressure to P h to a pressure slightly higher than the pressure Pi in the high-pressure reactor 3;

[0115] S12: Disassemble the reactor system and sample preparation system; clean the high-pressure reactor 3 and change the experimental pressure P i , repeat S2 to S12;

[0116] S13: Plotting the generation temperature T i With pressure P i The change curve.

[0117] S14: Change the speed v of the stepper motor 13, repeat S2 to S13, different speeds v i The generation temperature T i With pressure P i The change curve.

[0118] S15: changing the roughness μ of the metal crystal block 10, repeating S2 to S13, with different roughness μ i The generation temperature T i With pressure P i The change curve.

[0119] S16: Fit the experimental data to obtain an empirical formula for hydrate formation temperature that comprehensively considers pressure, fluid flow rate, and surface roughness factors.

[0120] The empirical formula for temperature is:

[0121] T i =A(P i ) D ×B(v i ) E ×C(μ i ) F

[0122] Where, T i is the temperature when hydrate is formed, °C; v i is the speed, r / min; μ i is the surface roughness, dimensionless; A, B, C, D, E, and F are all constants.

[0123] Take a water-producing gas well in a block in the northwest region as an example. The well has the characteristics of low temperature, high pressure and high yield. According to a method for rapid determination of the dynamic generation temperature of high-pressure hydrates, first, the sample preparation system is used to inject experimental formation water and natural gas into the reactor system, and the stirring system and the high and low temperature alternating test box are started to conduct experiments according to the experimental pressure and speed. And nonlinear cooling is performed. After a period of reaction, observe whether hydrates are generated and record the generation temperature. Change the test pressure and speed to obtain the hydrate generation temperature under different pressures and speeds.

[0124] The present invention tests the hydrate formation temperature of the well under different pressures and rotation speeds. The results are shown in the attached figure. Figure 5 As shown, the hydrate formation temperature at the speed of 5r / s and 10r / s, and the pressure of 42MPa, 35MPa, 27MPa, 18MPa, 10MPa, and 5MPa, respectively, is obtained. At the same speed, the higher the pressure, the higher the hydrate formation temperature; at the same pressure, the higher the speed, the higher the hydrate formation temperature. The results show that the present invention can accurately measure the hydrate formation temperature under high pressure conditions.

[0125] The alternative means of the present invention is to use a gas-liquid-solid three-phase state model to calculate the hydrate formation temperature under different pressures through a programming method.

[0126] The above is a specific description of the implementation mode of the present invention, but the present invention is not limited to the described embodiments. Those skilled in the art may make various equivalent modifications or substitutions without violating the spirit of the present invention, and these equivalents or substitutions are all included in the scope defined by the claims of the present invention.

Claims

1. A device for quickly measuring the dynamic generation temperature of high-pressure hydrates. It is characterized in that include: A reactor system, the reactor system comprising a high-low temperature alternating test box (2) using nonlinear temperature reduction and a high-pressure reactor (3) located in the high-low temperature alternating test box (2); A stirring system, the stirring system is located in the high and low temperature alternating test box (2), and stirs the experimental fluid in the high pressure reactor (3) by means of magnetic coupling; A sample preparation system, the sample preparation system comprising a liquid sample preparation subsystem and a gas sample preparation subsystem, the liquid sample preparation subsystem and the gas sample preparation subsystem are both located outside the high and low temperature alternating test box (2), and are both connected to the high pressure reactor (3) through pipelines to prepare samples for the experiment; An observation system is located in the high and low temperature alternating test box (2) and is used to observe the experiment inside the high pressure reactor (3).

2. The measuring device according to claim 1, It is characterized in that The reactor system further comprises a top cover (4), a loading and unloading hole (5), a sealing gasket I (8), a pressure-resistant transparent medium (9), a sealing gasket II (36) and a metal crystal block (10); The high-pressure reactor (3) is provided with an opening on the side, the top cover (4) is screwed onto the opening in a fixed connection manner through a loading and unloading hole (5), the top cover (4) is provided with a visual window for observation by the observation system, the sealing gasket I (8), the pressure-resistant transparent medium (9), and the sealing gasket II (36) are sequentially assembled in the top cover (4), and the metal crystal block (10) is arranged on the pressure-resistant transparent medium (9) and is located inside the high-pressure reactor (3).

3. The measuring device according to claim 2, It is characterized in that The metal crystal block (10) is made of oil pipe or gas pipeline material, and the metal crystal block (10) comprises a plurality of metal crystal blocks with different roughness.

4. The measuring device according to claim 1, It is characterized in that The reactor system further comprises a temperature sensor (1), a reactor support frame (11), a liquid inlet stop valve IV (30) and an air inlet stop valve IV (33); The temperature sensor (1) is arranged on the high-pressure reactor (3), the high-pressure reactor (3) is mounted on the reactor support frame (11), the high-pressure reactor (3) is connected to a liquid supply pipeline and a gas supply pipeline, and the liquid inlet stop valve IV (30) and the gas inlet stop valve IV (33) are respectively arranged on the liquid supply pipeline and the gas supply pipeline.

5. The measuring device according to claim 4, It is characterized in that The reactor system further comprises a three-way valve (17), a liquid outlet stop valve (16), a back pressure controller (15) and a liquid collecting bottle (14); The liquid supply pipeline is connected to the liquid outlet pipeline via a tee (17); the liquid outlet stop valve (16) and the back pressure controller (15) are arranged on the liquid outlet pipeline in sequence along the fluid flow direction; and the liquid collecting bottle (14) is arranged at the outlet of the liquid outlet pipeline.

6. The measuring device according to claim 4, It is characterized in that The stirring system comprises a stepping motor (13), a strong magnetic metal block I (12), a soft pad (35), a metal sealing bearing (31), a strong magnetic metal block II (32) and a resin rotor (34); The stepper motor (13) is mounted on a reactor support frame (11) and is located below the high-pressure reactor (3); the strong magnetic metal block I (12) is mounted on an upward rotating shaft of the stepper motor (13); a concave hole is provided at the bottom of the interior of the high-pressure reactor (3); the soft pad (35) is mounted in the concave hole; the metal sealing bearing (31) is mounted on the soft pad (35) in the concave hole; the strong magnetic metal block II (32) is embedded in the center hole of the metal sealing bearing (31); and the resin rotor (34) is mounted on the strong magnetic metal block II (32); The strong magnetic metal block I (12) and the strong magnetic metal block II (32) are matched with each other, and the stepping motor (13) drives the strong magnetic metal block I (12) to rotate, and the strong magnetic metal block I (12) drives the strong magnetic metal block II (32) to rotate, and drives the resin rotor (34) to rotate, so as to stir the experimental fluid in the high-pressure reactor (3).

7. The measuring device according to claim 4, It is characterized in that The liquid preparation subsystem comprises a high-pressure displacement pump I (23), a pressure sensor I (22), a liquid inlet stop valve I (21), a liquid inlet stop valve II (20), an intermediate container I (19) and a liquid inlet stop valve III (18); The high-pressure displacement pump I (23), the liquid inlet stop valve I (21), the liquid inlet stop valve II (20), the intermediate container I (19) and the liquid inlet stop valve III (18) are connected in sequence through pipelines. The pressure sensor I (22) is installed on the pipeline between the high-pressure displacement pump I (23) and the liquid inlet stop valve I (21). The liquid inlet stop valve III (18) is connected to the liquid inlet stop valve IV (30) through a pipeline.

8. The measuring device according to claim 4, It is characterized in that The gas matching subsystem comprises a high-pressure displacement pump II (25), a pressure sensor II (26), an air intake stop valve I (24), an air intake stop valve II (27), an intermediate container II (28) and an air intake stop valve III (29); The high-pressure displacement pump II (25), the air intake stop valve I (24), the air intake stop valve II (27), the intermediate container II (28) and the air intake stop valve III (29) are connected in sequence through pipelines. The pressure sensor II (26) is installed on the pipeline between the high-pressure displacement pump II (25) and the air intake stop valve I (24). The air intake stop valve III (29) is connected to the air intake stop valve IV (33) through a pipeline.

9. The measuring device according to claim 2, It is characterized in that The observation system comprises an industrial camera (6) and a support frame (7), wherein the industrial camera (6) is mounted on the support frame (7), and the camera end of the industrial camera (6) faces the visual window of the top cover (4).

10. A method for rapid determination of dynamic formation temperature of high-pressure hydrates. It is characterized in that The following steps are involved: S1: cleaning the autoclave (3): cleaning the entire autoclave (3) with an organic solvent and drying it; S2: Prepare the test sample: fill the intermediate container I (19) with formation water, fill the intermediate container II (28) with the test natural gas sample, and pressurize it to the test pressure P i , and keep the pressure constant; S3: Evacuate the reactor system and connect it to the sample preparation system; S4: Maintain pressure and transfer sample: Open the liquid inlet stop valve, use the high-pressure displacement pump I (23) to inject the formation water in the intermediate container I (19) into the high-pressure reactor (3), until half of the metal crystal block (10) is submerged, then close the liquid inlet stop valve, open the gas inlet stop valve, use the high-pressure displacement pump II (25) to inject the natural gas in the intermediate container II (28) into the high-pressure reactor (3), and pressurize it until the value of the pressure sensor II (26) is equal to P i , the high-pressure displacement pump II (25) stops pumping and maintains a constant pressure, and then closes the air intake stop valve; S5: The back pressure controller (15) loads the back pressure to make the back pressure P h Equal to the pressure P in the high pressure reactor (3) i ; S6: Start the high and low temperature alternating test chamber (2) to raise the temperature of the high pressure reactor (3) to the formation temperature T max , and keep the temperature constant; S7: Start the stirring system, which rotates at a certain speed v to simulate the flow state of the wellbore or surface pipeline; S8: Cooling: using the high and low temperature alternating test chamber (2) to cool in a nonlinear way; S9: Observation: Start the industrial camera (6) and record the real-time temperature T; S10: Formation temperature verification: Review the images recorded by the industrial camera (6) to find the temperature T when the hydrate is first formed. i ; S11: Turn off the stirring system and the high and low temperature alternating test chamber (2), and use the back pressure controller (15) to reduce the back pressure P h , making it lower than the experimental test pressure P i , open the liquid inlet stop valve IV (30) and the liquid outlet stop valve (16), release all the experimental fluid in the high-pressure reactor (3) into the liquid collecting bottle (14), close the liquid outlet stop valve (16), and then use the back pressure controller (15) to increase the back pressure to P h to a pressure higher than the pressure Pi in the high-pressure reactor (3); S12: Disassemble the reactor system and sample preparation system; clean the high-pressure reactor (3), and change the experimental pressure P i , repeat S2 to S12; S13: Plotting the generation temperature T i With pressure P i The change curve.

11. The assay method according to claim 10, It is characterized in that Also includes: S14: Change the speed v of the stepping motor (13), repeat S2 to S13, different speeds v i The generation temperature T i With pressure P i The change curve.

12. The assay method according to claim 11, It is characterized in that Also includes: S15: changing the roughness μ of the metal crystal block (10), repeating S2 to S13, with different roughness μ i The generation temperature T i With pressure P i The change curve.

13. The assay method according to claim 12, It is characterized in that Also includes: S16: Fit the experimental data to obtain an empirical formula for hydrate formation temperature that comprehensively considers pressure, fluid flow rate, and surface roughness factors.

14. The assay method according to claim 13, It is characterized in that The temperature empirical formula is: T i =A(P i ) D ×B(v i ) E ×C(μ i ) F ; Where, T i is the temperature when hydrate is formed, °C; v i is the speed, r / min; μ i is the surface roughness, dimensionless; A, B, C, D, E, and F are all constants.

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