Fluid flow and stability performance testing apparatus and method of use

Abstract

This invention relates to the field of oil and gas extraction technology, and particularly to a fluid flow and stability performance testing device and its usage method. The technical solution is as follows: a screw pump connects the lower part of a mixing tank to the first inlet of a foam generator; the output end of a first gas cylinder is connected to the second inlet of the foam generator via a first one-way valve; the output end of the foam generator is connected to the inlet of a simulated wellbore via a pipeline and a high-pressure shut-off valve; a second gas cylinder is connected to the simulated wellbore via a pipeline and a second one-way valve; one or more high-definition cameras are installed on the outside of the simulated wellbore; and a sedimentation tank is connected to the outlet end of the simulated wellbore. The beneficial effects are: the gas-liquid ratio of this invention is more uniform and the foaming efficiency is significantly improved. By improving the structure of the foam generator, improvements are made to stability, flowability, and testing methods, thereby fully utilizing the sand-carrying function of the foam fluid, thus providing experimental data support for oilfield production enhancement, profile control, and water shut-off.

Description

Technical Field

[0001] This invention relates to the field of oil and gas extraction technology, and in particular to a fluid flow and stability performance testing device and its usage method. Background Technology

[0002] With the gradual depletion of conventional oil and gas reservoirs, the development of deep, ultra-deep, and low-permeability oil and gas reservoirs has become a key focus. These formations typically have the following characteristics: (1) low permeability, making it difficult for conventional fracturing fluids to form effective fractures. (2) low formation pressure, making them prone to leakage and requiring low-density fluids with high sand-carrying capacity. (3) water-sensitive formations are sensitive to water-based fracturing fluids, which can easily cause formation damage. These characteristics seriously affect the development of oil and gas fields. In order to improve the recovery rate of oil and gas fields, it is necessary to develop efficient oil displacement technologies. Due to its unique physical properties, such as low density, high viscosity, and strong sand-carrying capacity, foam fluid has become an important means of oil displacement.

[0003] In oilfield development, proppant transport technology is one of the key means to improve oil well production and permeability. Its core lies in effectively transporting proppant (such as sand particles) into fractures to support them and improve their conductivity. The diversity and complexity of proppant transport methods allow oilfield engineers to select the most suitable proppant transport scheme based on different oil well geological conditions and production needs.

[0004] Liquid proppant carrying fluids are one of the most widely used proppant carrying methods. Liquid proppant carrying fluids mainly include water-based, oil-based, and hybrid-based proppant carrying fluids. Water-based proppant carrying fluids are widely used in oil wells with large fracture widths and coarse proppant particles due to their low cost and good environmental performance. By adding thickeners and surfactants, their viscosity can be significantly increased, thus better carrying proppant particles into the fractures. However, the viscosity of water-based proppant carrying fluids is relatively limited, resulting in slightly insufficient ability to support fractures, and the filtration loss is relatively large in high-permeability formations, potentially leading to formation contamination. Oil-based proppant carrying fluids have higher viscosity and stronger supporting capacity, making them suitable for oil wells with smaller fracture widths and finer proppant particles. They have good wettability to the reservoir, enabling better entry into fractures and improving fracture conductivity. However, oil-based proppant carrying fluids are more expensive, have a certain environmental impact, require specialized recovery and treatment equipment to reduce potential environmental hazards, and the construction process is also more complex. Hybrid sand-carrying fluid combines the advantages of water-based and oil-based sand-carrying fluids. By adjusting the ratio of the two, the performance of the sand-carrying fluid is optimized. It combines the low cost of water-based sand-carrying fluids with the high viscosity of oil-based sand-carrying fluids, making it more adaptable and allowing for flexible adjustments based on different geological conditions and operational needs. However, the formulation of hybrid sand-carrying fluid is relatively complex, requiring precise control of the ratio of water-based to oil-based fluids, which makes construction more difficult and the cost relatively higher.

[0005] Gas-based proppant-carrying fluids offer new possibilities for proppant-carrying technology. Nitrogen foam proppant-carrying fluids form high-viscosity foam by injecting nitrogen into a liquid matrix. This high-viscosity, low-density foam, with its minimal filtration loss, effectively carries proppant particles into fractures and distributes them evenly, while minimizing reservoir damage. It is particularly suitable for low-pressure, loss-prone, and water-sensitive formations. Carbon dioxide proppant-carrying fluids also have unique advantages. Under certain conditions, carbon dioxide can form a supercritical state, exhibiting excellent solubility and diffusivity. This allows for better interaction with formation fluids, improving the permeability and proppant-carrying capacity of the fluid and further enhancing fracture conductivity. Furthermore, carbon dioxide, as a common gas, is relatively inexpensive to obtain and use, and under suitable conditions, it can be absorbed and utilized by the formation, reducing the difficulty and cost of flowback treatment. Nitrogen, as an inert gas, is non-corrosive to equipment and reservoirs, environmentally friendly, and meets the environmental protection requirements of modern oilfield development. Carbon dioxide itself also has certain environmental advantages. Under reasonable control of dosage and construction conditions, its impact on the environment is relatively small. Moreover, its mechanism of action in the formation can further optimize the support effect of fractures and the flow characteristics of fluids. When combined with nitrogen-carrying sand fluid, it can exert a more comprehensive advantage and further improve the overall performance of sand-carrying fluid.

[0006] The low density and high viscosity of foam fluid enable it to better encapsulate and suspend sand particles. The low density helps reduce pressure on the wellbore, preventing excessive impact on the formation, while the high viscosity effectively prevents sand particles from settling rapidly in the fluid, thus better carrying them back to the surface. Furthermore, it exhibits good stability in underground environments, especially under complex formation conditions, maintaining its sand-carrying capacity. Even in harsh environments such as high temperature and high salinity, its performance does not significantly degrade, making it effective in various types of oil and gas wells.

[0007] Foam-carrying sand fluid has the following advantages: (1) The high-viscosity foam structure can carry a large number of sand particles into the depth of the fracture like a "conveyor belt", ensuring that the sand particles are evenly distributed, improving the fracture support effect, and increasing the oil and gas conduction capacity. Moreover, the high viscosity slows down the settling speed of the sand particles, keeps them suspended for a longer time, avoids accumulation at the inlet, effectively fills the fracture, and reduces the risk of fracture closure. When the sand particles are evenly distributed, they can also better support the fracture, prevent the fracture from closing prematurely during oil and gas extraction, prolong the effective conduction time, and improve the recovery rate. (2) It is suitable for low-pressure, leakage, and water-sensitive formations. It reduces the risk of collapse in low-pressure formations, seals leakage channels in leakage formations, and reduces water-sensitive damage in water-sensitive formations, protecting formation stability. The low-density foam fluid has low pressure on the reservoir and low filtration loss, preventing solid particles from clogging the pores, protecting the reservoir permeability, and reducing production capacity damage. (3) After entering the formation, foam-carrying sand fluid will not cause clay expansion in water-sensitive formations like water-based sand-carrying fluid. In addition, its low filtration loss also reduces the pollution to the formation and helps protect the permeability of the oil and gas reservoir. (4) Low-density foam fluid has low pressure on the reservoir and low filtration loss, preventing solid particles from clogging the pores, protecting the reservoir permeability, and reducing production damage. (5) The use of foam-carrying sand fluid reduces the amount of water used and reduces dependence on water resources. At the same time, its low filtration loss and recyclability also reduce the generation of waste liquid and reduce environmental pollution.

[0008] Foam fluids have demonstrated significant advantages in enhancing oil recovery and developing complex reservoirs, but they are still affected by various performance factors that prevent them from fully realizing their sand-carrying advantages. These factors are mainly as follows:

[0009] (1) The foaming efficiency needs to be improved: uneven mixing of gas and liquid in the foam generator can lead to large differences in local foam quality. For example, in some foam generators with unreasonable structural design, problems such as insufficient gas-liquid contact, insufficient foam generation or short foam half-life are likely to occur, resulting in a longer operation cycle (such as needing to inject foam multiple times when killing wells).

[0010] (2) Uneven gas-liquid ratio: Due to defects in the mixing structure (such as short flow channel and low stirring efficiency) or fluctuations in operating conditions, radial "gas core-liquid film" stratification and axial ratio pulsation (amplitude ±10%) are likely to occur, resulting in uneven foam particle size (large bubbles > 3mm), stability difference of up to 50%, and even wellbore pressure imbalance or equipment erosion and wear.

[0011] (3) Poor reliability of high-pressure seals: When the working pressure is >30MPa, components such as flanges and bolts are prone to fatigue fracture due to stress concentration. The aging rate of seals (such as rubber O-rings) is accelerated at high temperatures (>120℃), and the leakage rate increases by 5% per year.

[0012] In summary, the performance of foam fluid is key to fully realizing its sand-carrying advantage. Improvements are needed in aspects such as stability, flowability, and testing methods to fully leverage the sand-carrying function of foam fluid. Summary of the Invention

[0013] The purpose of this invention is to address the aforementioned deficiencies in the existing technology by providing a fluid flow and stability performance testing device and method. Through improvements in the structure, stability, flowability, and testing methods of the foam generator, the device fully utilizes the sand-carrying function of the foam fluid, thereby providing experimental data support for oilfield production enhancement, profile control, and water shut-off.

[0014] The present invention discloses a fluid flow and stability performance testing device, the technical solution of which includes a mixing tank, an opening valve, a screw pump, a first high-pressure shut-off valve, a first check valve, a first gas cylinder, a second check valve, a second gas cylinder, a second high-pressure shut-off valve, a sedimentation tank, a foam generator, a simulated wellbore, and a high-definition camera. The lower part of the mixing tank is connected to the input end of the screw pump via a pipeline and the opening valve. The output end of the screw pump is connected to the first inlet of the foam generator via a pipeline. The output end of the first gas cylinder is connected to the second inlet of the foam generator via a pipeline and the first check valve. The output end of the foam generator is connected to the inlet end of the simulated wellbore via a pipeline and the first high-pressure shut-off valve. The second gas cylinder is connected to the inlet end of the simulated wellbore via a pipeline and the second check valve. One or more high-definition cameras are provided on the outside of the simulated wellbore. The outlet end of the simulated wellbore is connected to the sedimentation tank via a pipeline and the second high-pressure shut-off valve.

[0015] Preferably, a first venting line and a first venting valve are installed on the pipeline between the opening valve and the input end of the screw pump, and a second venting line and a second venting valve are installed on the pipeline between the second high-pressure shut-off valve and the sedimentation tank.

[0016] Preferably, a liquid flow meter is installed on the pipeline between the output end of the screw pump and the foam generator, a foam flow meter is installed on the pipeline between the output end of the foam generator and the simulated wellbore, a first gas flow meter is installed on the pipeline between the output end of the first gas cylinder and the foam generator, a second gas flow meter is installed on the pipeline between the output end of the second gas cylinder and the simulated wellbore, and a mass flow meter is installed on the pipeline between the second high-pressure shut-off valve and the settling tank.

[0017] Preferably, the foam generator includes a sealed bearing, a rotating cylinder wall, a circular cylinder wall, an air supply pipe, a liquid supply pipe, a coaxial forward and reverse rotation device, a connecting arm, a stirring device, a foam output pipe, and an isolation box. The rotating cylinder wall has circular cylinder walls installed at both ends to form the main body of the foam generator. A sealed bearing is provided between the circular cylinder wall and the rotating cylinder wall. An air supply pipe and a liquid supply pipe are installed on the left end of the circular cylinder wall. The outer cylinder and inner shaft of the stirring device pass through the center of the circular cylinder wall. The right end of the outer cylinder is fixedly connected to the rotating cylinder wall via the connecting arm, and the right end of the inner shaft is fixedly connected to the stirring rod inside the rotating cylinder wall. A foam output pipe is installed in the middle of the right end of the circular cylinder wall. An isolation box is installed on one side of the main body of the foam generator, and a coaxial forward and reverse rotation device is installed inside the isolation box.

[0018] Preferably, the coaxial forward and reverse rotation device includes an outer cylinder gear, an inner shaft gear, a power gear, and a power transmission shaft. The surface of the outer cylinder gear meshes with the power gear, and its rear side is fixedly connected to the left end of the outer cylinder. The surface of the inner shaft gear meshes with the power gear, and its middle part is fixedly connected to the left end of the inner shaft. A power transmission shaft is provided on the top of the power gear, and the rotation of the power gear drives the outer cylinder gear and the inner shaft gear to rotate in opposite directions.

[0019] Preferably, the above-mentioned stirring device includes a stirring rod, an inner shaft, and an outer cylinder. The right end of the inner shaft is fixedly connected to the left end of the stirring rod. The stirring rod is composed of two sets of gate-shaped structures connected together. The outer diameter of the inner shaft is smaller than the inner diameter of the outer cylinder.

[0020] Preferably, the inner wall of the rotating cylinder is provided with multiple sets of axially arranged turbulence ribs.

[0021] Preferably, the simulated wellbore includes a circular cylinder wall, a viewing window, and an electric heating belt. Multiple viewing windows are distributed on the circular cylinder wall, and the surface of the circular cylinder wall is wrapped with an electric heating belt.

[0022] Preferably, the above-mentioned sedimentation tank includes a sedimentation tank wall, a top cover, a hinge, a drain valve, a top cover lock, a support, a filter basket, a handle, and an inlet pipe. The top side of the sedimentation tank wall is connected to the top cover via a hinge. A support and a drain valve are provided at the bottom of the sedimentation tank wall. A filter basket is installed in the inner cavity of the sedimentation tank wall. A handle is provided at the top of the filter basket. The side wall of the filter basket is movably connected to the inlet pipe. The filter pores of the filter basket are smaller than the particle size of the sand.

[0023] The method for using the fluid flow and stability performance testing device mentioned in this invention comprises a fluid stability performance testing method and a fluid flow performance testing method.

[0024] (a) Fluid stability performance testing methods, including the following procedures:

[0025] (i) Turn on the electric heating belt to heat the simulated wellbore, so that the temperature inside the simulated wellbore rises to 60°C;

[0026] (ii) Prepare a mixture of experimental sand and water with a sand ratio of 10% in a mixing tank. Stir thoroughly according to the mass percentage. After the water and experimental sand are fully mixed, add the foaming agent and stir again to ensure the solution is fully mixed.

[0027] (iii) Open the opening valve, start the screw pump, and adjust the liquid flow rate so that the liquid enters the delivery pipe of the foam generator at the set flow rate. At the same time, open the first check valve to inject the gas from the first gas cylinder into the gas delivery pipe of the foam generator.

[0028] (iv) Turn on the motor on the upper side of the isolation box. The power transmission shaft transmits kinetic energy to make the coaxial forward and reverse device run. The rotation of the power gear drives the outer cylinder gear and the inner shaft gear to rotate in opposite directions, driving the outer cylinder and the inner shaft to rotate in opposite directions. The outer cylinder drives the rotating cylinder wall to rotate, and the inner shaft drives the stirring rod to rotate in the opposite direction. The turbulence ribs on the rotating cylinder wall increase the disturbance to the fluid, prevent the experimental sand from depositing at the bottom of the rotating cylinder wall, and make the liquid-gas sand fully mixed to produce sand-carrying foam.

[0029] (v) The liquid flow meter and the first gas flow meter display the values, and then the liquid-gas flow rate entering the foam generator is adjusted to control the gas-liquid ratio;

[0030] (vi) Open the first high-pressure shut-off valve and close the second high-pressure shut-off valve to inject foam fluid into the simulated well. Control the amount of foam liquid entering the simulated well through the display of the foam flow meter. Then close the first high-pressure shut-off valve and open the second check valve to inject the gas from the second gas cylinder into the simulated well. Control the amount of gas entering the simulated well through the second gas flow meter. After the pressure in the simulated well is increased to 4MPa, the experimental phenomena in the simulated well are captured by a high-definition camera through the viewing window and the experimental phenomena are recorded.

[0031] (vii) Open the second high-pressure shut-off valve to allow the multiphase solution to flow into the settling tank;

[0032] (viii) The multiphase solution enters the filter basket through the inlet pipe. The filter basket separates the sand particles and the liquid. The sand particles are kept in the filter basket, and the liquid is discharged through the drain valve. After the experiment, the top cover lock is opened, the top cover is opened, and the filter basket is lifted out through the handle to clean the sand particles.

[0033] (ix) Perform the stability test of the foam fluid without sand, at 4MPa and 60℃, according to the above steps. Compare it with the stability test with sand, at 4MPa and 60℃ in the above steps. Observe the change in the stability of the foam fluid under the experimental conditions. Similarly, by changing the experimental sand, sand ratio, gas-liquid ratio, pressure and temperature, the stability test of the foam fluid is carried out by multiple factors.

[0034] (ii) Fluid flow performance testing methods, including the following procedures:

[0035] (I) Ensure all valves are closed before testing;

[0036] (II) Prepare a mixture of experimental sand and water with a sand ratio of 10% in a mixing tank. Stir the mixture according to the mass percentage. After it is fully mixed, add the foaming agent and stir again until the foam volume ratio reaches 80%. After the mixture meets the experimental standard, conduct the experiment.

[0037] (III) Open the opening valve, start the screw pump, and adjust the liquid flow rate so that the liquid enters the delivery pipe of the foam generator at the set flow rate. At the same time, open the first check valve to inject gas into the gas delivery pipe of the foam generator.

[0038] (IV) Turn on the motor on the upper side of the isolation box. The power transmission shaft transmits kinetic energy to make the coaxial forward and reverse device run, driving the outer cylinder and inner shaft to rotate in opposite directions. The outer cylinder drives the rotating cylinder wall to rotate, and the inner shaft drives the stirring rod to rotate in the opposite direction. The turbulence on the rotating cylinder wall is increased by the turbulence ribs, which prevents the experimental sand from depositing at the bottom of the rotating cylinder wall, so that the liquid, gas and sand are fully mixed and sand-carrying foam is generated.

[0039] (V) By controlling the liquid flow meter and the first gas flow meter, the liquid-gas flow rate entering the foam generator is adjusted to control the gas-liquid-sand ratio;

[0040] (VI) Unlike the fluid stability performance test, the fluid flow performance test is conducted at normal temperature and pressure, so the second check valve and the electric heating belt are both in the closed state.

[0041] (VII) Open the first high-pressure shut-off valve and the second high-pressure shut-off valve. The foam fluid carries sand into the simulated well. The high-definition camera captures the experimental phenomena in the simulated well through the viewing window and records the experimental phenomena.

[0042] (VIII) The multiphase solution flows into the sand settling tank through the pipeline: After the multiphase solution enters the filter basket through the inlet pipe, the sand particles and liquid are separated by the filter basket. The sand particles are kept in the filter basket, and the liquid is discharged through the drain valve. After the experiment, the top cover lock is opened, the top cover is opened, and the filter basket is lifted out through the handle to clean the sand particles.

[0043] (IX) Following the steps above, by changing different sand ratios, the flow performance of foam fluid under different foam volume ratios can be tested.

[0044] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0045] The present invention achieves a more uniform gas-liquid ratio and significantly improved foaming efficiency. Through the mixing of gas and liquid in the foam generator, and through the designed coaxial forward and reverse rotation device, the rotation of the power gear drives the outer cylinder gear and the inner shaft gear to rotate in opposite directions, driving the outer cylinder and the inner shaft to rotate in opposite directions. The outer cylinder drives the rotating cylinder wall to rotate, and the inner shaft drives the stirring rod to rotate in the opposite direction. The turbulence ribs on the rotating cylinder wall increase the disturbance to the fluid, preventing the experimental sand from depositing at the bottom of the rotating cylinder wall, so that the liquid, gas and sand are fully mixed to produce sand-carrying foam. This reduces the problems caused by structural defects, such as "gas core-liquid film" stratification, large axial ratio pulsation amplitude, resulting in uneven foam particle size, stability difference of up to 50%, and even wellbore pressure imbalance or equipment erosion and wear.

[0046] Furthermore, the high-pressure sealing reliability of this invention is better, with a sealed bearing between the circular cylinder wall and the rotating cylinder wall, ensuring both the airtightness of the device and preventing leakage. By simulating the foam fluid behavior under high temperature and high pressure, this invention can effectively evaluate the stability and rheology of foam, thus providing key data support for oilfield production enhancement, profile control, and water shut-off. In addition, the technological improvements can reduce energy consumption and equipment maintenance costs during testing, enabling sustainable resource utilization and bringing long-term economic and environmental benefits to oilfield development. This is crucial for promoting the advancement of oil and gas extraction technology and the sustainable development of the industry. Attached Figure Description

[0047] Figure 1 This is a schematic diagram of the structure of the present invention;

[0048] Figure 2 This is a schematic diagram of a foam generator.

[0049] Figure 3 This is a schematic diagram of the coaxial forward and reverse rotation device;

[0050] Figure 4 This is a schematic diagram of the stirring device;

[0051] Figure 5 This is a schematic diagram of a partial structure of the inner side of the rotating cylinder wall;

[0052] Figure 6 This is a top view of the rotating cylinder wall;

[0053] Figure 7 This is a schematic diagram simulating the front of a wellbore.

[0054] Figure 8 This is a schematic diagram of the sedimentation tank device;

[0055] In the diagram: 1. Mixing tank; 2. Opening valve; 3. First vent valve; 4. Screw pump; 5. Liquid flow meter; 6. Foam flow meter; 7. First high-pressure shut-off valve; 8. First check valve; 9. First gas flow meter; 10. First gas cylinder; 11. Second check valve; 12. Second gas flow meter; 13. Second high-pressure shut-off valve; 14. Second vent valve; 15. Mass flow meter; 16. Grit chamber; 17. Foam generator; 18. Simulated wellbore; 19. High-definition camera; 20. Sealed bearing; 21. Rotating cylinder wall; 22. Circular cylinder wall; 23. Gas pipeline; 24. 25. Infusion tube; 26. Coaxial forward and reverse rotation device; 27. Connecting arm; 28. Stirring device; 29. ​​Foam output tube; 30. Isolation box; 31. Outer cylinder gear; 32. Inner shaft gear; 33. Power gear; 34. Power transmission shaft; 35. Inner shaft; 36. Outer cylinder; 37. Stirring rod; 40. Baffle rib; 41. Circular cylinder wall; 42. Viewing window; 43. Electric heating belt; 44. Sand settling tank wall; 45. Sand particles; 46. Liquid; 47. Top cover; 48. Hinge; 49. Drain valve; 50. Top cover lock; 51. Support; 52. Filter basket; 53. Handle; 54. Inlet pipe. Detailed Implementation

[0056] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0057] Reference Figures 1-8 The present invention discloses a fluid flow and stability performance testing device, comprising a mixing tank 1, an opening valve 2, a screw pump 4, a first high-pressure shut-off valve 7, a first one-way valve 8, a first gas cylinder 10, a second one-way valve 11, a second gas cylinder 13, a second high-pressure shut-off valve 14, a sedimentation tank 17, a foam generator 18, a simulated wellbore 19, and a high-definition camera 20. The lower part of the mixing tank 1 is connected to the input end of the screw pump 4 via a pipeline and the opening valve 2, and the output end of the screw pump 4 is connected to the first one-way valve of the foam generator 18 via a pipeline. The first gas cylinder 10 is connected to the second inlet of the foam generator 18 via a pipeline and a first one-way valve 8. The output end of the foam generator 18 is connected to the inlet of the simulated well shaft 19 via a pipeline and a first high-pressure shut-off valve 7. The second gas cylinder 13 is connected to the inlet of the simulated well shaft 19 via a pipeline and a second one-way valve 11. One or more high-definition cameras 20 are provided on the outside of the simulated well shaft 19. The outlet end of the simulated well shaft 19 is connected to the settling tank 17 via a pipeline and a second high-pressure shut-off valve 14.

[0058] Reference Figure 1 The invention relates to a first venting pipeline and a first venting valve 3 installed on the pipeline between the opening valve 2 and the input end of the screw pump 4, and a second venting pipeline and a second venting valve 15 installed on the pipeline between the second high-pressure shut-off valve 14 and the sedimentation tank 17.

[0059] Specifically, a liquid flow meter 5 is installed on the pipeline between the output end of the screw pump 4 and the foam generator 18, a foam flow meter 6 is installed on the pipeline between the output end of the foam generator 18 and the simulated well shaft 19, a first gas flow meter 9 is installed on the pipeline between the output end of the first gas cylinder 10 and the foam generator 18, a second gas flow meter 12 is installed on the pipeline between the output end of the second gas cylinder 13 and the simulated well shaft 19, and a mass flow meter 16 is installed on the pipeline between the second high-pressure shut-off valve 14 and the sedimentation tank 17.

[0060] Reference Figure 2 The foam generator 18 mentioned in this invention includes a sealed bearing 21, a rotating cylinder wall 22, a circular cylinder wall 23, an air supply pipe 24, an infusion pipe 25, a coaxial forward and reverse rotation device 26, a connecting arm 27, a stirring device 28, a foam output pipe 29, and an isolation box 30. The rotating cylinder wall 22 is equipped with circular cylinder walls 23 at both ends to form the main body of the foam generator. A sealed bearing 21 is provided between the circular cylinder wall 23 and the rotating cylinder wall 22. The air supply pipe 24 and the infusion pipe 25 are installed on the left end of the circular cylinder wall 23. The outer cylinder 36 and the inner shaft 35 of the stirring device 28 pass through the center of the circular cylinder wall 23. The right end of the outer cylinder 36 is fixedly connected to the rotating cylinder wall 22 through the connecting arm 27. The right end of the inner shaft 35 is fixedly connected to the stirring rod 37 in the inner cavity of the rotating cylinder wall 22. The foam output pipe 29 is installed in the middle of the right end of the circular cylinder wall 23. An isolation box 30 is installed on one side of the main body of the foam generator. The coaxial forward and reverse rotation device 26 is installed in the inner cavity of the isolation box 30.

[0061] Reference Figure 3 The coaxial forward and reverse rotation device 26 mentioned in this invention includes an outer cylinder gear 31, an inner shaft gear 32, a power gear 33, and a power transmission shaft 34. The surface of the outer cylinder gear 31 meshes with the power gear 33, and its rear side is fixedly connected to the left end of the outer cylinder 36. The surface of the inner shaft gear 32 meshes with the power gear 33, and its middle part is fixedly connected to the left end of the inner shaft 35. A power transmission shaft 34 is provided on the top of the power gear 33. The rotation of the power gear 33 drives the outer cylinder gear 31 and the inner shaft gear 32 to rotate in opposite directions.

[0062] Reference Figure 4 The stirring device 28 mentioned in this invention includes a stirring rod 37, an inner shaft 35, and an outer cylinder 36. The right end of the inner shaft 35 is fixedly connected to the left end of the stirring rod 37. The stirring rod 37 is composed of two sets of gate-shaped structures connected together. The outer diameter of the inner shaft 35 is smaller than the inner diameter of the outer cylinder 36.

[0063] Reference Figure 5 and Figure 6The inner wall of the rotating cylinder 22 mentioned in this invention has multiple sets of axially arranged turbulence ribs 40, which increases the friction force on the fluid, prevents the experimental sand from depositing at the bottom of the inner wall of the rotating cylinder 22, and at the same time allows the liquid-gas-sand to mix fully and efficiently generate sand-carrying foam.

[0064] Reference Figure 7 The simulated well shaft 19 mentioned in this invention includes a circular cylinder wall 41, a viewing window 42, and an electric heating belt 43. Multiple viewing windows 42 are distributed on the circular cylinder wall 41, and the surface of the circular cylinder wall 41 is wrapped with an electric heating belt 43.

[0065] Reference Figure 8 The sedimentation tank 17 mentioned in this invention includes a sedimentation tank wall 44, a top cover 47, a hinge 48, a drain valve 49, a top cover lock 50, a support 51, a filter basket 52, a handle 53, and an inlet pipe 54. The top side of the sedimentation tank wall 44 is connected to the top cover 47 via the hinge 48. The support 51 and the drain valve 49 are provided at the bottom of the sedimentation tank wall 44. The filter basket 52 is installed in the inner cavity of the sedimentation tank wall 44. The top of the filter basket 52 is provided with a handle 53. The side wall of the filter basket 52 is movably connected to the inlet pipe 54. The filter pores of the filter basket 52 are smaller than the particle size of the sand.

[0066] The method for using the fluid flow and stability performance testing device mentioned in this invention comprises a fluid stability performance testing method and a fluid flow performance testing method.

[0067] (a) Fluid stability performance testing methods, including the following procedures:

[0068] (i) Turn on the electric heating belt 43 to heat the simulated well 19, so that the temperature inside the simulated well 19 rises to 60°C;

[0069] (ii) Prepare a mixture of experimental sand and water with a sand ratio of 10% in mixing tank 1. Stir thoroughly according to the mass percentage. After the water and experimental sand are thoroughly mixed, add the foaming agent and stir again to make the solution fully mixed.

[0070] (iii) Open the opening valve 2, start the screw pump 4, adjust the liquid flow rate, so that the liquid enters the delivery pipe 25 of the foam generator 18 at the set flow rate, and at the same time open the first one-way valve 8 to inject the gas from the first gas cylinder 10 into the gas delivery pipe 24 of the foam generator 18.

[0071] (iv) Turn on the motor on the upper side of the isolation box 30. The power transmission shaft 34 transmits kinetic energy to make the coaxial forward and reverse device 26 run. The rotation of the power gear 33 drives the outer cylinder gear 31 and the inner shaft gear 32 to rotate in the opposite direction, driving the outer cylinder 36 and the inner shaft 35 to rotate in the opposite direction. The outer cylinder 36 drives the rotating cylinder wall 22 to rotate, and the inner shaft 35 drives the stirring rod 37 to rotate in the opposite direction. The turbulence ribs 40 on the rotating cylinder wall 22 increase the disturbance to the fluid, prevent the experimental sand from depositing at the bottom of the rotating cylinder wall 22, and make the liquid-gas sand fully mixed to produce sand-carrying foam.

[0072] (v) The values ​​are displayed by the liquid flow meter 5 and the first gas flow meter 9, and then the liquid-gas flow rate entering the foam generator 18 is adjusted to control the gas-liquid-sand ratio.

[0073] (vi) Open the first high-pressure shut-off valve 7 and close the second high-pressure shut-off valve 14 to inject foam fluid into the simulated well 19. Control the amount of foam liquid entering the simulated well 19 through the display of the foam flow meter 6. Then close the first high-pressure shut-off valve 7 and open the second one-way valve 11 to inject the gas from the second gas cylinder 13 into the simulated well 19. Control the amount of gas entering the simulated well 19 through the second gas flow meter 12. After the pressure in the simulated well 19 is increased to 4MPa, the high-definition camera 20 captures the experimental phenomena in the simulated well 19 through the viewing window 42 and records the experimental phenomena.

[0074] (vii) Open the second high-pressure shut-off valve 14 to allow the multiphase solution to flow into the settling tank 17;

[0075] (viii) The multiphase solution enters the filter basket 52 through the inlet pipe 54. The filter basket 52 separates the sand particles 45 and the liquid 46. The sand particles are kept in the filter basket 52, and the liquid 46 is discharged through the drain valve 49. After the experiment, the top cover lock 50 is opened, the top cover 47 is opened, and the filter basket 52 is lifted out through the handle 53 to clean the sand particles.

[0076] (ix) Following the steps above, conduct a stability test on the foam fluid without sand at 4 MPa and 60°C. Compare this stability test results with those obtained with sand at 4 MPa and 60°C, and observe the changes in the stability of the foam fluid under these experimental conditions. Similarly, by changing the experimental sand, sand ratio, gas-liquid ratio, pressure, and temperature, conduct a multi-factor stability test on the foam fluid.

[0077] (ii) Fluid flow performance testing methods, including the following procedures:

[0078] (I) Ensure all valves are closed before testing;

[0079] (II) Prepare a mixture of experimental sand and water with a sand ratio of 10% in mixing tank 1. Stir the mixture according to the mass percentage. After it is fully mixed, add the foaming agent and stir again to make the foam volume ratio reach 80%. After the mixture meets the experimental standard, carry out the experiment.

[0080] (III) Open the opening valve 2, start the screw pump 4, adjust the liquid flow rate, so that the liquid enters the delivery pipe 25 of the foam generator 18 at the set flow rate, and at the same time open the first one-way valve 8 to inject gas into the gas delivery pipe 24 of the foam generator 18.

[0081] (IV) Turn on the motor on the upper side of the isolation box 30. The power transmission shaft 34 transmits kinetic energy to make the coaxial forward and reverse device 26 run, driving the outer cylinder 36 and the inner shaft 35 to rotate in opposite directions. The outer cylinder 36 drives the rotating cylinder wall 22 to rotate, and the inner shaft 35 drives the stirring rod 37 to rotate in the opposite direction. The turbulence ribs 40 on the rotating cylinder wall 22 increase the disturbance to the fluid, prevent the experimental sand from depositing at the bottom of the rotating cylinder wall 22, and make the liquid-gas sand fully mixed to produce sand-carrying foam.

[0082] (V) By controlling the liquid flow meter 5 and the first gas flow meter 9, the liquid-gas flow rate entering the foam generator 18 is adjusted to control the gas-liquid ratio;

[0083] (VI) Unlike the fluid stability performance test, the fluid flow performance test is conducted at normal temperature and pressure, so the second one-way valve 11 and the electric heating belt 43 are both in the closed state.

[0084] (VII) Open the first high-pressure shut-off valve 7 and the second high-pressure shut-off valve 14. The foam fluid carries sand into the simulated wellbore 19. The high-definition camera 20 captures the experimental phenomena in the simulated wellbore 19 through the viewing window 42 and records the experimental phenomena.

[0085] (VIII) The multiphase solution flows into the sedimentation tank 17 through the pipeline: After the multiphase solution enters the filter basket 52 through the inlet pipe 54, the filter basket 52 separates the sand particles 45 and the liquid 46. The sand particles are kept in the filter basket 52, and the liquid 46 is discharged through the drain valve 49. After the experiment, the top cover lock 50 is opened, the top cover 47 is opened, and the filter basket 52 is lifted out through the handle 53 to clean the sand particles.

[0086] (IX) Following the steps above, the flow properties of foam fluid under different sand ratios can be tested by changing the sand ratio.

[0087] In addition, the method for calculating the fluid sand carrying capacity is as follows:

[0088] After the experiment, the sand in sedimentation tank 17 was removed and weighed to determine the sand mass m and the volume of sand carried. V1 = m / ρ, therefore, the sand carrying rate = (sand carrying volume V1 / total experimental sand volume V) × 100%.

[0089] The above description is merely a partial preferred embodiment of the present invention. Any person skilled in the art can modify the above-described technical solutions or modify them into equivalent technical solutions. Therefore, any simple modifications or equivalent transformations made based on the technical solutions of the present invention fall within the scope of protection claimed by the present invention.

Claims

1. A fluid flow and stability performance testing device, comprising a mixing tank (1), characterized in that: It also includes an opening valve (2), a screw pump (4), a first high-pressure shut-off valve (7), a first check valve (8), a first gas cylinder (10), a second check valve (11), a second gas cylinder (13), a second high-pressure shut-off valve (14), a sedimentation tank (17), a foam generator (18), a simulated wellbore (19), and a high-definition camera (20). The lower part of the mixing tank (1) is connected to the input end of the screw pump (4) through a pipeline and the opening valve (2). The output end of the screw pump (4) is connected to the first inlet of the foam generator (18) through a pipeline. The first gas cylinder (10) The output end of the foam generator (18) is connected to the second inlet of the foam generator (18) through a pipeline and a first one-way valve (8); the output end of the foam generator (18) is connected to the inlet end of the simulated well shaft (19) through a pipeline and a first high-pressure shut-off valve (7); the second gas cylinder (13) is connected to the inlet end of the simulated well shaft (19) through a pipeline and a second one-way valve (11); a set of more than one set of high-definition cameras (20) is provided on the outside of the simulated well shaft (19); the outlet end of the simulated well shaft (19) is connected to the sedimentation tank (17) through a pipeline and a second high-pressure shut-off valve (14). The foam generator (18) includes a sealed bearing (21), a rotating cylinder wall (22), a circular cylinder wall (23), an air supply pipe (24), a liquid supply pipe (25), a coaxial forward and reverse rotation device (26), a connecting arm (27), a stirring device (28), a foam output pipe (29), and an isolation box (30). The rotating cylinder wall (22) is equipped with circular cylinder walls (23) at both ends to form the main body of the foam generator. A sealed bearing (21) is provided between the circular cylinder wall (23) and the rotating cylinder wall (22). An air supply pipe is installed on the circular cylinder wall (23) at the left end. (24) and infusion tube (25), the outer cylinder (36) and inner shaft (35) of the stirring device (28) pass through the center of the circular cylinder wall (23), the right end of the outer cylinder (36) is fixedly connected to the rotating cylinder wall (22) through the connecting arm (27), and the right end of the inner shaft (35) is fixedly connected to the stirring rod (37) in the inner cavity of the rotating cylinder wall (22); a foam output pipe (29) is installed in the middle of the circular cylinder wall (23) at the right end; an isolation box (30) is installed on one side of the foam generator body, and a coaxial forward and reverse rotation device (26) is installed in the inner cavity of the isolation box (30).

2. The fluid flow and stability performance testing device according to claim 1, characterized in that: A first venting line and a first venting valve (3) are installed on the pipeline between the opening valve (2) and the input end of the screw pump (4), and a second venting line and a second venting valve (15) are installed on the pipeline between the second high-pressure shut-off valve (14) and the sedimentation tank (17).

3. The fluid flow and stability performance testing device according to claim 2, characterized in that: A liquid flow meter (5) is installed on the pipeline between the output end of the screw pump (4) and the foam generator (18), a foam flow meter (6) is installed on the pipeline between the output end of the foam generator (18) and the simulated well (19), a first gas flow meter (9) is installed on the pipeline between the output end of the first gas cylinder (10) and the foam generator (18), a second gas flow meter (12) is installed on the pipeline between the output end of the second gas cylinder (13) and the simulated well (19), and a mass flow meter (16) is installed on the pipeline between the second high-pressure shut-off valve (14) and the sedimentation tank (17).

4. The fluid flow and stability performance testing device according to claim 3, characterized in that: The coaxial forward and reverse rotation device (26) includes an outer cylinder gear (31), an inner shaft gear (32), a power gear (33), and a power transmission shaft (34). The surface of the outer cylinder gear (31) meshes with the power gear (33), and its rear side is fixedly connected to the left end of the outer cylinder (36). The surface of the inner shaft gear (32) meshes with the power gear (33), and its middle part is fixedly connected to the left end of the inner shaft (35). A power transmission shaft (34) is provided on the top of the power gear (33). The rotation of the power gear (33) drives the outer cylinder gear (31) and the inner shaft gear (32) to rotate in opposite directions.

5. The fluid flow and stability performance testing device according to claim 4, characterized in that: The stirring device (28) includes a stirring rod (37), an inner shaft (35), and an outer cylinder (36). The right end of the inner shaft (35) is fixedly connected to the left end of the stirring rod (37). The stirring rod (37) is composed of two sets of gate-shaped structures connected together. The outer diameter of the inner shaft (35) is smaller than the inner diameter of the outer cylinder (36).

6. The fluid flow and stability performance testing device according to claim 5, characterized in that: The inner wall of the rotating cylinder wall (22) is distributed with multiple sets of axially arranged turbulence ribs (40).

7. The fluid flow and stability performance testing device according to claim 6, characterized in that: The simulated wellbore (19) includes a circular cylinder wall (41), a viewing window (42), and an electric heating belt (43). Multiple viewing windows (42) are distributed on the circular cylinder wall (41), and the surface of the circular cylinder wall (41) is wrapped with an electric heating belt (43).

8. The fluid flow and stability performance testing device according to claim 7, characterized in that: The settling tank (17) includes a settling tank wall (44), a top cover (47), a hinge (48), a drain valve (49), a top cover lock (50), a bracket (51), a filter basket (52), a handle (53), and an inlet pipe (54). The top side of the settling tank wall (44) is connected to the top cover (47) by a hinge (48). A bracket (51) and a drain valve (49) are provided at the bottom of the settling tank wall (44). A filter basket (52) is installed in the inner cavity of the settling tank wall (44). A handle (53) is provided at the top of the filter basket (52). The side wall of the filter basket (52) is movably connected to the inlet pipe (54). The filter pores of the filter basket (52) are smaller than the particle size of the sand.

9. The method of using the fluid flow and stability performance testing device according to claim 8, characterized in that: This includes methods for testing fluid stability and fluid flow properties. (a) Fluid stability performance testing methods, including the following procedures: (i) Turn on the electric heating belt (43) to heat the simulated wellbore (19) so that the temperature inside the simulated wellbore (19) rises to 60°C; (ii) Prepare a mixture of experimental sand and water with a sand ratio of 10% in the mixing tank (1). Stir thoroughly according to the mass percentage. After the water and experimental sand are thoroughly mixed, add the foaming agent and stir again to make the solution fully mixed. (iii) Open the opening valve (2), start the screw pump (4), adjust the liquid flow rate, so that the liquid enters the delivery pipe (25) of the foam generator (18) at the set flow rate, and at the same time open the first check valve (8) to inject the gas from the first gas cylinder (10) into the gas delivery pipe (24) of the foam generator (18). (iv) Turn on the motor on the upper side of the isolation box (30), and transmit kinetic energy through the power transmission shaft (34) to make the coaxial forward and reverse device (26) run. The rotation of the power gear (33) drives the outer cylinder gear (31) and the inner shaft gear (32) to rotate in the opposite direction, driving the outer cylinder (36) and the inner shaft (35) to rotate in the opposite direction. The outer cylinder (36) drives the rotating cylinder wall (22) to rotate, and the inner shaft (35) drives the stirring rod (37) to rotate in the opposite direction. The turbulence ribs (40) on the rotating cylinder wall (22) increase the disturbance to the fluid, prevent the experimental sand from depositing at the bottom of the rotating cylinder wall (22), and make the liquid-gas sand fully mixed to produce sand-carrying foam. (v) The values ​​are displayed by the liquid flow meter (5) and the first gas flow meter (9), and the liquid-gas flow rate entering the foam generator (18) is adjusted to control the gas-liquid ratio; (vi) Open the first high-pressure shut-off valve (7), close the second high-pressure shut-off valve (14), inject the foam fluid into the simulated well (19), control the amount of foam liquid entering the simulated well (19) through the display of the foam flow meter (6), then close the first high-pressure shut-off valve (7), open the second check valve (11), inject the gas from the second gas cylinder (13) into the simulated well (19), control the amount of gas entering the simulated well (19) through the second gas flow meter (12), raise the pressure in the simulated well (19) to 4MPa, and capture the experimental phenomena in the simulated well (19) through the viewing window (42) of the high-definition camera (20), and record the experimental phenomena. (vii) Open the second high-pressure shut-off valve (14) to allow the solution to flow into the sedimentation tank (17); (viii) The solution enters the filter basket (52) through the inlet pipe (54), and the filter basket (52) separates the sand particles (45) and liquid (46). The sand particles are kept in the filter basket (52), and the liquid (46) is discharged through the drain valve (49). After the experiment, the top cover lock (50) is opened, the top cover (47) is opened, and the filter basket (52) is lifted out through the handle (53) to clean the sand particles. (ix) Perform the foam fluid stability test without sand, at 4MPa and 60℃ according to the above steps, and compare it with the foam stability test with sand, at 4MPa and 60℃ in the above steps. Observe the change in the stability of the foam fluid under the experimental conditions. Similarly, by changing the experimental sand, sand ratio, gas-liquid ratio, pressure and temperature, the stability test of the foam fluid is carried out by multiple factors. (ii) Fluid flow performance testing methods, including the following procedures: (I) Ensure all valves are closed before testing; (II) Prepare a mixture of experimental sand and water with a sand ratio of 10% in the mixing tank (1). Stir the mixture according to the mass percentage. After it is fully mixed, add the foaming agent and stir again to make the foam volume ratio reach 80%. After the mixture meets the experimental standard, carry out the experiment. (III) Open the opening valve (2), start the screw pump (4), adjust the liquid flow rate, so that the liquid enters the delivery pipe (25) of the foam generator (18) at the set flow rate, and at the same time open the first check valve (8) to inject gas into the gas delivery pipe (24) of the foam generator (18). (IV) Turn on the motor on the upper side of the isolation box (30), and the power transmission shaft (34) transmits kinetic energy to make the coaxial forward and reverse device (26) run, driving the outer cylinder (36) and the inner shaft (35) to rotate in opposite directions. The outer cylinder (36) drives the rotating cylinder wall (22) to rotate, and the inner shaft (35) drives the stirring rod (37) to rotate in the opposite direction. The turbulence ribs (40) on the rotating cylinder wall (22) increase the disturbance to the fluid, prevent the experimental sand from depositing at the bottom of the rotating cylinder wall (22), and make the liquid-gas sand fully mixed to generate sand-carrying foam. (V) By controlling the liquid flow meter (5) and the first gas flow meter (9), the liquid-gas flow rate entering the foam generator (18) is adjusted to control the gas-liquid ratio; (VI) Unlike the fluid stability performance test, the fluid flow performance test is conducted at normal temperature and pressure, so the second check valve (11) and the electric heating belt (43) are both in the closed state; (VII) Open the first high-pressure shut-off valve (7) and the second high-pressure shut-off valve (14), and the foam fluid carrying sand enters the simulated wellbore (19). The high-definition camera (20) captures the experimental phenomena in the simulated wellbore (19) through the viewing window (42) and records the experimental phenomena. (VIII) The multiphase solution flows into the sedimentation tank (17) through the pipeline: After the multiphase solution enters the filter basket (52) through the inlet pipe (54), the filter basket (52) separates the sand particles (45) and liquid (46). The sand particles are kept in the filter basket (52), and the liquid (46) is discharged through the drain valve (49). After the experiment, the top cover lock (50) is opened, the top cover (47) is opened, and the filter basket (52) is lifted out through the handle (53) to clean the sand particles. (IX) Following the steps above, the flow properties of foam fluid under different sand ratios can be tested by changing the sand ratio.

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