Fluid flow and stability performance testing device and use method

Abstract

The invention relates to the technical field of oil and gas exploitation, in particular to a fluid flowing and stability performance testing device and a using method. According to the technical scheme, the lower part of a liquid mixing tank is connected to a first inlet of a foam generator through a screw pump; the output end of the first gas cylinder is connected to a second inlet of the foam generator through a first one-way valve; the output end of the foam generator is connected to the inlet end of the simulation shaft through a pipeline and a high-pressure stop valve; the second gas cylinder is connected to the simulation shaft through a pipeline and a second one-way valve; more than one group of high-definition cameras are arranged on the outer side of the simulation shaft; and the outlet end of the simulation shaft is connected to a sand setting tank. The foam generator has the beneficial effects that the gas-liquid ratio is more uniform, the foaming efficiency is greatly improved, and the sand carrying function of foam fluid is fully played by improving the structure of the foam generator, the stability, the flowability, the testing method and the like, so that experimental data support is provided for the aspects of oil field yield increase, profile control, water plugging and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of oil and gas extraction, and in particular to a fluid flow and stability performance testing device and a use method thereof. Background Art

[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 focus. These formations usually have the following characteristics: (1) Low permeability, making it difficult for conventional fracturing fluids to form effective fractures. (2) Low formation pressure, prone to leakage, requiring low-density, high-sand-carrying fluids. (3) Water-sensitive formations are sensitive to water-based fracturing fluids, which can easily cause formation damage. These characteristics have seriously affected 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 recovery technology. Foam fluids have become an important oil recovery method due to their unique physical properties, such as low density, high viscosity, and strong sand-carrying capacity.

[0003] In oilfield development, sand-carrying technology is a key means of increasing well production and permeability. Its core is to effectively carry proppant (such as sand) into fractures, thereby supporting them and improving their conductivity. The diversity and complexity of sand-carrying methods enable oilfield engineers to select the most appropriate sand-carrying solution based on the geological conditions and production requirements of the wells.

[0004] Liquid sand-carrying fluid is one of the most widely used sand-carrying methods. Liquid sand-carrying fluids primarily include water-based, oil-based, and mixed-based fluids. Water-based fluids, due to their low cost and environmental friendliness, are widely used in oil wells with wider fractures and coarser sand particles. By adding thickeners and surfactants, their viscosity can be significantly increased, allowing them to better carry sand into fractures. However, the relatively limited viscosity of water-based fluids makes them less effective at supporting fractures. Furthermore, they experience high fluid loss in highly permeable formations, potentially leading to formation contamination. Oil-based fluids, on the other hand, have higher viscosity and greater support capacity, making them suitable for oil wells with smaller fractures and finer sand particles. They exhibit excellent wettability in the reservoir, enabling them to better penetrate fractures and improve fracture conductivity. However, oil-based fluids are costly and have certain environmental impacts, requiring specialized recovery and treatment equipment to mitigate potential environmental hazards. Furthermore, the application process is relatively complex. Mixed-base sand-carrying fluid combines the advantages of water-based and oil-based sand-carrying fluids. The performance of the sand-carrying fluid is optimized by adjusting the ratio of the two. It has both the low cost of water-based sand-carrying fluid and the high viscosity of oil-based sand-carrying fluid. It has stronger adaptability and can be flexibly adjusted according to different geological conditions and operational requirements. However, the formula of mixed-base sand-carrying fluid is relatively complex, and the ratio of water-based and oil-based needs to be precisely controlled. The construction is difficult and the cost is relatively high.

[0005] Gas-carrying fluids offer new possibilities for sand-carrying technology. Nitrogen foam sand-carrying fluids inject nitrogen into a liquid matrix to form a high-viscosity foam. With its high viscosity, low density, and minimal filtration loss, nitrogen foam sand-carrying fluids can effectively carry sand into fractures and evenly distribute it, while minimizing reservoir damage. They are particularly suitable for low-pressure, leaky, and water-sensitive formations. Carbon dioxide sand-carrying fluids also have unique advantages. Under certain conditions, carbon dioxide can form a supercritical state. Its excellent solubility and diffusivity allow for better interaction with fluids in the formation, helping to improve the permeability and sand-carrying capacity of the sand-carrying fluid and further enhance the conductivity of the fractures. Furthermore, as a common gas, carbon dioxide is relatively inexpensive to acquire and use, and under appropriate conditions, it can be absorbed and utilized by the formation, reducing the difficulty and cost of flowback treatment. Furthermore, as an inert gas, nitrogen is non-corrosive to equipment and reservoirs, and is environmentally friendly, meeting the environmental protection requirements of modern oilfield development. Carbon dioxide itself also has certain environmental advantages. Under reasonable control of dosage and construction conditions, it has little impact on the environment. Its action mechanism in the formation can further optimize the support effect of fractures and the flow characteristics of fluids. Combined with nitrogen sand-carrying fluid, it can bring out more comprehensive advantages and further improve the overall performance of the sand-carrying fluid.

[0006] Foam fluid has low density and high viscosity, properties that allow it to effectively encapsulate and suspend sand particles. Low density helps reduce pressure on the wellbore, preventing excessive impact on the formation, while high viscosity effectively prevents rapid sedimentation of sand particles in the fluid, thereby effectively carrying sand particles from the wellbore to the surface. Simultaneously, it exhibits excellent stability in underground environments, maintaining its sand-carrying performance, especially in complex formations. Its performance does not significantly degrade even in harsh environments such as high temperature and high salinity, making it effective in a wide range of oil and gas well types.

[0007] Foam sand-carrying fluid has the following advantages: (1) The high-viscosity foam structure can carry a large amount of sand into the deep cracks like a "conveyor belt", ensuring that the sand is evenly distributed, improving the fracture support effect, and increasing the oil and gas conductivity. The high viscosity slows down the sedimentation rate of the sand particles, keeps them in suspension for a longer time, avoids accumulation at the entrance, effectively fills the cracks, and reduces the risk of crack closure. When the sand particles are evenly distributed, they can also better support the cracks, prevent the cracks from closing prematurely during oil and gas production, extend the effective conductivity 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, blocks leakage channels in leakage formations, reduces water-sensitive damage in water-sensitive formations, and protects the stability of the formation. Low-density foam fluids exert low pressure on the reservoir and have low filtration loss, preventing solid particles from clogging pores, protecting the reservoir permeability, and reducing production capacity damage. (3) After entering the formation, the foam sand-carrying fluid will not cause clay expansion in water-sensitive formations like water-based sand-carrying fluids. In addition, its low fluid loss also reduces contamination of the formation, helping to protect the permeability of the oil and gas layer. (4) Low-density foam fluid exerts low pressure on the reservoir and has low fluid loss, preventing solid particles from clogging pores, protecting reservoir permeability, and reducing production capacity damage. (5) The use of foam sand-carrying fluid reduces water consumption and reduces dependence on water resources. At the same time, its low fluid loss and recyclability also reduce the generation of waste fluid and reduce pollution to the environment.

[0008] Foam fluids have demonstrated significant advantages in enhancing oil recovery and exploiting complex reservoirs. However, they are still affected by various performance factors, which prevent them from fully utilizing their sand-carrying advantages. The main factors are as follows: (1) Foaming efficiency needs to be improved: The uneven mixing of gas and liquid in the foam generator will 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 prone to occur, resulting in extended operation cycles (e.g., multiple foam injections are required when killing the well); (2) Uneven gas-liquid ratio: Due to defects in the mixing structure (such as short flow channels and low stirring efficiency) or fluctuations in operating conditions, radial "gas core-liquid film" stratification and axial ratio pulsation (amplitude ±10%) are prone to occur, resulting in uneven foam particle size (large bubbles >3mm) and stability differences of up to 50%, and even causing wellbore pressure imbalance or equipment erosion and wear; (3) Poor reliability of high-pressure sealing: When the working pressure is greater than 30 MPa, flanges, bolts and other components are prone to fatigue fracture due to stress concentration. The aging speed of seals (such as rubber O-rings) is accelerated at high temperatures (greater than 120°C), and the leakage rate increases by 5% each year. In summary, the performance of foam fluid is the key to fully exerting its advantages in carrying sand. Improvements are needed in terms of stability, fluidity and testing methods to fully exert the sand-carrying function of foam fluid. Summary of the Invention

[0009] The purpose of the present invention is to address the above-mentioned defects in the prior art and provide a fluid flow and stability performance testing device and method of use. By improving the foam generator structure, stability, fluidity and testing methods, the sand-carrying function of the foam fluid is fully utilized, thereby providing experimental data support in oil field production increase, profile control and water plugging.

[0010] The present invention mentions a fluid flow and stability performance testing device, and its technical solution is: it includes a mixing tank, an opening valve, a screw pump, a first high-pressure stop valve, a first one-way valve, a first gas cylinder, a second one-way valve, a second gas cylinder, a second high-pressure stop valve, a sand settling 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 through a pipeline and an opening valve, and the output end of the screw pump is connected to the first inlet of the foam generator through a pipeline; the output end of the first gas cylinder is connected to the second inlet of the foam generator through a pipeline and a first one-way valve; the output end of the foam generator is connected to the inlet end of the simulated wellbore through a pipeline and a first high-pressure stop valve, and the second gas cylinder is connected to the inlet end of the simulated wellbore through a pipeline and a second one-way valve; one or more high-definition cameras are provided on the outside of the simulated wellbore; and the outlet end of the simulated wellbore is connected to the sand settling tank through a pipeline and a second high-pressure stop valve.

[0011] Preferably, a first drain line and a first drain valve are installed on the pipeline between the above-mentioned opening valve and the input end of the screw pump, and a second drain line and a second drain valve are installed on the pipeline between the second high-pressure stop valve and the sand settling tank.

[0012] Preferably, a liquid flow meter is installed on the pipeline between the output end of the above-mentioned 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 stop valve and the sand settling tank.

[0013] Preferably, the above-mentioned foam generator includes a sealed bearing, a rotating cylinder wall, a circular cylinder wall, an air pipe, a liquid pipe, a coaxial forward and reverse rotation device, a connecting arm, a stirring device, a foam output pipe, and an isolation box. Circular cylinder walls are installed at both ends of the rotating cylinder wall to form the foam generator body. A sealed bearing is provided between the circular cylinder wall and the rotating cylinder wall. The air pipe and the liquid pipe are installed on the circular cylinder wall at the left end. The outer cylinder and the 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 through the connecting arm, and the right end of the inner shaft is fixedly connected to the stirring rod in the inner cavity of the rotating cylinder wall; the foam output pipe is installed in the middle of the circular cylinder wall at the right end; an isolation box is installed on one side of the foam generator body, and the coaxial forward and reverse rotation device is installed in the inner cavity of the isolation box.

[0014] Preferably, the above-mentioned 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 is engaged with the power gear, and the rear side is fixedly connected to the left end of the outer cylinder; the surface of the inner shaft gear is engaged with the power gear, and the 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 the opposite direction.

[0015] Preferably, the 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 groups of door-shaped structures. The outer diameter of the inner shaft is smaller than the inner diameter of the outer cylinder.

[0016] Preferably, a plurality of groups of axially arranged spoiler ribs are distributed on the inner wall of the rotating cylinder.

[0017] Preferably, the simulated wellbore comprises a circular wall, visual windows, and an electric heating belt. A plurality of visual windows are distributed on the circular wall, and the surface of the circular wall is wrapped with an electric heating belt.

[0018] Preferably, the above-mentioned sand settling tank includes a sand settling tank wall, an upper cover, a hinge, a drain valve, an upper cover lock, a bracket, a filter basket, a handle, and a liquid inlet pipe. The top side of the sand settling tank wall is connected to the upper cover through a hinge, and a bracket and a drain valve are provided at the bottom of the sand settling tank wall. A filter basket is installed in the inner cavity of the sand settling tank wall, and a handle is provided on the top of the filter basket. The side wall of the filter basket is movably connected to the liquid inlet pipe, and the filter pores of the filter basket are smaller than the particle size of the sand particles.

[0019] The method for using the fluid flow and stability performance testing device mentioned in the present invention has a technical solution that includes a fluid stability performance testing method and a fluid flow performance testing method. (1) Fluid stability performance test method, including the following process: (i) Turn on the electric heating tape to heat the simulated wellbore until the temperature inside the simulated wellbore rises to 60°C; (ii) Prepare a mixture of test sand and clean water in a mixing tank with a sand ratio of 10%, stir thoroughly according to the mass percentage, add a foaming agent after the clean water and test sand are thoroughly mixed, and stir again to fully mix the solution; (iii) opening the opening valve, starting the screw pump, regulating the liquid flow rate so that the liquid enters the liquid delivery pipe of the foam generator at a set flow rate, and simultaneously opening the first one-way valve to inject the gas from the first gas cylinder into the gas delivery pipe of the foam generator; (iv) Turn on the motor on the upper side of the isolation box, and the kinetic energy is transmitted by the power transmission shaft to operate the 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 the opposite direction, driving the outer cylinder and the inner shaft to rotate in the opposite direction. 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 flow disturbance ribs on the rotating cylinder wall increase the disturbance of the fluid, preventing the experimental sand from settling at the bottom of the rotating cylinder wall, so that the liquid, gas and sand are fully mixed to produce sand-carrying foam; (v) regulating the liquid and gas flow rates entering the foam generator and controlling the gas-liquid ratio by using the displayed values ​​of the liquid flow meter and the first gas flow meter; (vi) Open the first high-pressure shut-off valve, close the second high-pressure shut-off valve, and inject foam fluid into the simulated wellbore. The amount of foam liquid entering the simulated wellbore is controlled by the display of the foam flowmeter. Next, close the first high-pressure shut-off valve, open the second one-way valve, and inject gas from the second gas cylinder into the simulated wellbore. The amount of gas entering the simulated wellbore is controlled by the second gas flowmeter. After the pressure in the simulated wellbore is increased to 4 MPa, a high-definition camera is used to capture and record the experimental phenomena in the simulated wellbore through the visual window. (vii) opening the second high-pressure shut-off valve to allow the multiphase solution to flow into the grit chamber; (viii) The multiphase solution enters the filter basket through the liquid inlet pipe, where the filter basket separates the sand and liquid. The sand is retained in the filter basket, and the liquid is discharged through the drain valve. After the experiment, the lid is unlocked, the lid is opened, and the filter basket is lifted out by the handle to remove the sand. (ix) Conduct a foam fluid stability test without sand, at 4 MPa and 60°C according to the above steps, and compare it with the stability test with sand, at 4 MPa and 60°C in the above steps to observe the changes in the stability of the foam fluid under these experimental conditions. Similarly, conduct a multi-factor cross-test of the foam fluid stability by changing the experimental sand, sand ratio, gas-liquid ratio, pressure and temperature; (2) Fluid flow performance test method, including the following process: (I) Ensure all valves are closed before testing; (II) Prepare a mixture of test sand and clean water in a mixing tank with a sand ratio of 10%. 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 reaches the experimental standard, conduct the experiment; (III) opening the opening valve, starting the screw pump, regulating the liquid flow rate so that the liquid enters the liquid delivery pipe of the foam generator at the set flow rate, and simultaneously opening the first one-way valve to inject gas into the gas delivery pipe of the foam generator; (IV) Turn on the motor on the upper side of the isolation box, and the power transmission shaft transmits kinetic energy to operate the coaxial forward and reverse rotation device, 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 flow disturbance ribs on the rotating cylinder wall increase the disturbance of the fluid, preventing the experimental sand from settling at the bottom of the rotating cylinder wall, so that the liquid, gas and sand are fully mixed to produce sand-carrying foam; (V) regulating the liquid and gas flow rates entering the foam generator and controlling the gas-liquid-sand ratio by operating the liquid flow meter and the first gas flow meter; (VI) Different from the fluid stability performance test, the fluid flow performance test is conducted at normal temperature and pressure, so the second one-way valve and the electric heating belt are both in the closed state; (VII) opening the first high-pressure stop valve and the second high-pressure stop valve, allowing the foam fluid to carry sand into the simulated wellbore, and using a high-definition camera to capture and record experimental phenomena in the simulated wellbore through a visual window; (VIII) The multiphase solution flows into the grit chamber through the pipeline: After the multiphase solution enters the filter basket through the liquid inlet pipe, the filter basket separates the sand and liquid. The sand is stored in the filter basket, and the liquid is discharged through the drain valve. After the experiment, the lid is unlocked, the lid is opened, and the filter basket is lifted out by the handle to clean the sand. (IX) Referring to the above steps, by changing different sand ratios, the flow properties of the foam fluid under different foam volume ratios can be tested.

[0020] Compared with the prior art, the beneficial effects of the present invention are as follows: The gas-liquid ratio of the present invention is more uniform and the foaming efficiency is greatly improved. Through the mixing of gas and liquid in the foam generator, the outer cylinder gear and the inner shaft gear are driven to rotate in opposite directions by the designed coaxial forward and reverse device under the rotation of the power gear, 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 disturbance of the fluid is increased by the spoiler ribs on the rotating cylinder wall, 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; the "gas core-liquid film" stratification and large axial ratio pulsation amplitude caused by structural defects are reduced, resulting in uneven foam particle size and stability differences of up to 50%, and even causing wellbore pressure imbalance or equipment erosion and wear. In addition, the high-pressure seal of the present invention has better reliability. A sealed bearing is provided between the circular cylinder wall and the rotating cylinder wall, which not only ensures the air tightness of the device but also prevents leakage of the device. The present invention can effectively evaluate the stability and rheology of the foam by simulating the behavior of foam fluid under high temperature and high pressure environment, thereby providing key data support in oil field production increase, profile adjustment and water plugging. In addition, the improvement of technology can also reduce energy consumption and equipment maintenance costs during the test process, realize the sustainable use of resources, and bring long-term economic and environmental benefits to oil field development. It is crucial to promote the advancement of oil and gas extraction technology and the sustainable development of the industry. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a structural schematic diagram of the present invention; Figure 2 It is a structural diagram of a foam generator; Figure 3 It is a structural diagram of a coaxial forward and reverse rotation device; Figure 4 It is a structural schematic diagram of a stirring device; Figure 5 It is a schematic diagram of the local structure of the inner side of the rotating cylinder wall; Figure 6 It is a schematic diagram of the top view of the rotating cylinder wall; Figure 7 It is a structural diagram simulating the front of the wellbore; Figure 8 It is a structural diagram of the grit tank device; In the figure: mixing tank 1, opening valve 2, first emptying valve 3, screw pump 4, liquid flowmeter 5, foam flowmeter 6, first high-pressure stop valve 7, first one-way valve 8, first gas flowmeter 9, first gas cylinder 10, second one-way valve 11, second gas flowmeter 12, second gas cylinder 13, second high-pressure stop valve 14, second emptying valve 15, mass flowmeter 16, sand settling tank 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 , infusion tube 25, coaxial forward and reverse rotation device 26, connecting arm 27, stirring device 28, foam output pipe 29, isolation box 30, outer cylinder gear 31, inner shaft gear 32, power gear 33, power transmission shaft 34, inner shaft 35, outer cylinder 36, stirring rod 37, spoiler rib 40, circular cylinder wall 41, visual window 42, electric heating belt 43, sand settling tank wall 44, sand 45, liquid 46, upper cover 47, hinge 48, drain valve 49, upper cover lock 50, bracket 51, filter basket 52, handle 53, liquid inlet pipe 54. DETAILED DESCRIPTION

[0022] The preferred embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0023] Reference Figures 1-8 The present invention relates to 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 stop 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 stop valve 14, a sand settling 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, and the output end of the screw pump 4 is connected to the first one of the foam generator 18 through a pipeline. inlet; the output end of the first gas cylinder 10 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 wellbore 19 through a pipeline and a first high-pressure stop valve 7, and the second gas cylinder 13 is connected to the inlet end of the simulated wellbore 19 through a pipeline and a second one-way valve 11; one or more high-definition cameras 20 are provided on the outside of the simulated wellbore 19; the outlet end of the simulated wellbore 19 is connected to the sand settling tank 17 through a pipeline and a second high-pressure stop valve 14.

[0024] Reference Figure 1 A first drain line and a first drain valve 3 are installed on the pipeline between the opening valve 2 and the input end of the screw pump 4 mentioned in the present invention, and a second drain line and a second drain valve 15 are installed on the pipeline between the second high-pressure stop valve 14 and the sand settling tank 17.

[0025] Among them, a liquid flowmeter 5 is installed on the pipeline between the output end of the above-mentioned screw pump 4 and the foam generator 18, a foam flowmeter 6 is installed on the pipeline between the output end of the foam generator 18 and the simulated wellbore 19, a first gas flowmeter 9 is installed on the pipeline between the output end of the first gas cylinder 10 and the foam generator 18, a second gas flowmeter 12 is installed on the pipeline between the output end of the second gas cylinder 13 and the simulated wellbore 19, and a mass flowmeter 16 is installed on the pipeline between the second high-pressure stop valve 14 and the sand settling tank 17.

[0026] Reference Figure 2 The foam generator 18 mentioned in the present invention includes a sealed bearing 21, a rotating cylinder wall 22, a circular cylinder wall 23, an air pipe 24, a liquid pipe 25, a coaxial forward and reverse device 26, a connecting arm 27, a stirring device 28, a foam output pipe 29, and an isolation box 30. The circular cylinder wall 23 is installed at both ends of the rotating cylinder wall 22 to form a foam generator body. A sealed bearing 21 is provided between the circular cylinder wall 23 and the rotating cylinder wall 22. The air pipe 24 and the liquid pipe 25 are installed on the circular cylinder wall 23 at the left end. 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, 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; the foam output pipe 29 is installed in the middle of the circular cylinder wall 23 at the right end; the isolation box 30 is installed on one side of the foam generator body, and the coaxial forward and reverse device 26 is installed in the inner cavity of the isolation box 30.

[0027] Reference Figure 3 The coaxial forward and reverse rotation device 26 mentioned in the present 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 is engaged with the power gear 33, and the rear side is fixedly connected to the left end of the outer cylinder 36; the surface of the inner shaft gear 32 is engaged with the power gear 33, and the middle part is fixedly connected to the left end of the inner shaft 35. A power transmission shaft 34 is provided at the top of the power gear 33, and 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.

[0028] Reference Figure 4 The stirring device 28 mentioned in the present 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 groups of gate-shaped structures. The outer diameter of the inner shaft 35 is smaller than the inner diameter of the outer cylinder 36.

[0029] Reference Figure 5 and Figure 6The inner wall of the rotating cylinder wall 22 mentioned in the present invention is distributed with multiple groups of axially arranged spoiler ribs 40, which increase the friction on the fluid, prevent the experimental sand from depositing at the bottom of the inner wall of the rotating cylinder wall 22, and at the same time fully mix the liquid, gas and sand to efficiently generate sand-carrying foam.

[0030] Reference Figure 7 The simulated wellbore 19 mentioned in the present invention includes a circular wall 41, a visual window 42, and an electric heating belt 43. A plurality of visual windows 42 are distributed on the circular wall 41, and an electric heating belt 43 is wrapped around the surface of the circular wall 41.

[0031] Reference Figure 8 The grit tank 17 mentioned in the present invention includes a grit tank wall 44, an upper cover 47, a hinge 48, a drain valve 49, an upper cover lock 50, a bracket 51, a filter basket 52, a handle 53, and a liquid inlet pipe 54. The top side of the grit tank wall 44 is connected to the upper cover 47 through a hinge 48, and a bracket 51 and a drain valve 49 are provided at the bottom of the grit tank wall 44. A filter basket 52 is installed in the inner cavity of the grit tank wall 44, and a handle 53 is provided on the top of the filter basket 52. The side wall of the filter basket 52 is movably connected to the liquid inlet pipe 54. The filter pores of the filter basket 52 are smaller than the particle size of the sand particles.

[0032] The method for using the fluid flow and stability performance testing device mentioned in the present invention has a technical solution that includes a fluid stability performance testing method and a fluid flow performance testing method. (1) Fluid stability performance test method, including the following process: (i) turning on the electric heating belt 43 to heat the simulated wellbore 19, raising the temperature inside the simulated wellbore 19 to 60°C; (ii) In a mixing tank 1, a mixture of test sand and clean water is prepared to a sand ratio of 10%, and the mixture is stirred thoroughly according to the mass percentage. After the clean water and the test sand are thoroughly mixed, a foaming agent is added, and the mixture is stirred again to thoroughly mix the solution; (iii) opening the opening valve 2, starting the screw pump 4, and regulating the liquid flow rate so that the liquid enters the liquid delivery pipe 25 of the foam generator 18 at the set flow rate. Simultaneously, the first one-way valve 8 is opened to inject the gas from the first gas cylinder 10 into the gas delivery pipe 24 of the foam generator 18; (iv) Turning on the motor on the upper side of the isolation box 30, the kinetic energy is transmitted by the power transmission shaft 34, so that the coaxial forward and reverse rotation device 26 is in operation. 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 flow disturbance ribs 40 on the rotating cylinder wall 22 increase the disturbance of the fluid, prevent the experimental sand from settling at the bottom of the rotating cylinder wall 22, and fully mix the liquid, gas and sand to produce sand-carrying foam; (v) The liquid flow meter 5 and the first gas flow meter 9 display values, and then adjust the liquid and gas flow entering the foam generator 18 to control the gas-liquid-sand ratio; (vi) Opening the first high-pressure shut-off valve 7 and closing the second high-pressure shut-off valve 14, injecting foam fluid into the simulated wellbore 19, and controlling the amount of foam liquid entering the simulated wellbore 19 by means of the display of the foam flowmeter 6. Subsequently, closing the first high-pressure shut-off valve 7, opening the second one-way valve 11, and injecting gas from the second gas cylinder 13 into the simulated wellbore 19, and controlling the amount of gas entering the simulated wellbore 19 by means of the second gas flowmeter 12. After the pressure in the simulated wellbore 19 is increased to 4 MPa, the high-definition camera 20 captures and records the experimental phenomena in the simulated wellbore 19 through the visual window 42; (vii) opening the second high-pressure shut-off valve 14 to allow the multiphase solution to flow into the grit chamber 17; (viii) The multiphase solution enters the filter basket 52 through the liquid inlet pipe 54, where it is separated into sand 45 and liquid 46. The sand remains in the filter basket 52, while the liquid 46 is discharged through the drain valve 49. After the experiment, the lid lock 50 is unlocked, the lid 47 is opened, and the filter basket 52 is lifted out using the handle 53 to remove the sand. (ix) Follow the above steps to conduct a foam fluid stability test without sand, 4MPa, 60℃, and compare it with the stability test with sand, 4MPa, 60℃ in the above steps to observe the stability changes of the foam fluid under these 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 under multiple factors. (2) Fluid flow performance test method, including the following process: (I) Ensure all valves are closed before testing; (II) In a mixing tank 1, a mixture of test sand and clean water is prepared to a sand ratio of 10%. The mixture is stirred according to the mass percentage. After it is fully mixed, a foaming agent is added and stirred again until the foam volume ratio reaches 80%. After the mixture reaches the test standard, the test is carried out; (III) Opening the opening valve 2, starting the screw pump 4, and regulating the liquid flow rate so that the liquid enters the liquid delivery pipe 25 of the foam generator 18 at the set flow rate. At the same time, opening the first one-way valve 8, and injecting gas into the gas delivery pipe 24 of the foam generator 18; (IV) Turning on the motor on the upper side of the isolation box 30, the power transmission shaft 34 transmits kinetic energy, causing the coaxial forward and reverse rotation device 26 to operate, 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 flow disturbance ribs 40 on the rotating cylinder wall 22 increase the disturbance of the fluid, preventing the experimental sand from settling at the bottom of the rotating cylinder wall 22, and ensuring that the liquid, gas and sand are fully mixed to generate sand-carrying foam; (V) regulating the liquid and gas flow rates entering the foam generator 18 and controlling the gas-liquid ratio by operating the liquid flow meter 5 and the first gas flow meter 9; (VI) Unlike the fluid stability performance test, the fluid flow performance test is conducted at room temperature and pressure, so the second one-way valve 11 and the electric heating belt 43 are both in the closed state; (VII) opening the first high-pressure stop valve 7 and the second high-pressure stop valve 14, allowing the foam fluid to carry sand into the simulated wellbore 19, and the high-definition camera 20 to capture and record experimental phenomena in the simulated wellbore 19 through the visual window 42; (VIII) The multiphase solution flows into the grit chamber 17 through the pipeline: After the multiphase solution enters the filter basket 52 through the liquid inlet pipe 54, the filter basket 52 separates the sand 45 and the liquid 46. The sand is stored in the filter basket 52, and the liquid 46 is discharged through the drain valve 49. After the experiment, the upper cover lock 50 is unlocked, the upper cover 47 is opened, and the filter basket 52 is lifted out by the handle 53 to remove the sand. (IX) Referring to the above steps, by changing different sand ratios, the flow properties of the foam fluid under different sand ratios can be tested.

[0033] In addition, the calculation method of fluid sand carrying rate is as follows: After the experiment, take out the sand from the sand settling tank 17 and weigh it to know the mass m of the sand and the volume of the sand carried. V1 = m / ρ, so the sand carrying rate = (sand carrying volume V1 / total volume of experimental sand V) × 100%.

[0034] The above descriptions are merely some preferred embodiments of the present invention. Anyone skilled in the art may be able to modify the above-described technical solutions or convert them into equivalent technical solutions. Therefore, any corresponding simple modifications or equivalent transformations 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: The invention also includes an opening valve (2), a screw pump (4), a first high-pressure stop 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 stop valve (14), a sand settling 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), and 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 ) 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 wellbore (19) through a pipeline and a first high-pressure stop valve (7), and the second gas cylinder (13) is connected to the inlet end of the simulated wellbore (19) through a pipeline and a second one-way valve (11); one or more high-definition cameras (20) are provided on the outside of the simulated wellbore (19); and the outlet end of the simulated wellbore (19) is connected to the sand settling tank (17) through a pipeline and a second high-pressure stop valve (14).

2. The fluid flow and stability performance testing device according to claim 1, characterized in that: A first drain line and a first drain valve (3) are installed on the pipeline between the opening valve (2) and the input end of the screw pump (4), and a second drain line and a second drain valve (15) are installed on the pipeline between the second high-pressure stop valve (14) and the sand settling 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 wellbore (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 wellbore (19), and a mass flow meter (16) is installed on the pipeline between the second high-pressure stop valve (14) and the sand settling tank (17).

4. The fluid flow and stability performance testing device according to claim 3, characterized in that: The foam generator (18) comprises a sealed bearing (21), a rotating cylinder wall (22), a circular cylinder wall (23), an air delivery pipe (24), a liquid delivery 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). Circular cylinder walls (23) are installed at both ends of the rotating cylinder wall (22) to form a foam generator body. A sealed bearing (21) is provided between the circular cylinder wall (23) and the rotating cylinder wall (22). An air delivery pipe is installed on the circular cylinder wall (23) at the left end. (24) and the infusion tube (25), 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), 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).

5. The fluid flow and stability performance testing device according to claim 4, characterized in that: The coaxial forward and reverse rotation device (26) comprises 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) is meshed with the power gear (33), and the rear side is fixedly connected to the left end of the outer cylinder (36); the surface of the inner shaft gear (32) is meshed with the power gear (33), and the 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), and 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.

6. The fluid flow and stability performance testing device according to claim 5, characterized in that: The stirring device (28) comprises 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 groups of gate-shaped structures. The outer diameter of the inner shaft (35) is smaller than the inner diameter of the outer cylinder (36).

7. The fluid flow and stability performance testing device according to claim 6, characterized in that: The inner wall of the rotating cylinder wall (22) is provided with a plurality of groups of axially arranged flow-turbulating ribs (40).

8. The fluid flow and stability performance testing device according to claim 7, characterized in that: The simulated wellbore (19) comprises a circular wall (41), visual windows (42), and an electric heating belt (43). A plurality of visual windows (42) are distributed on the circular wall (41), and the surface of the circular wall (41) is wrapped with an electric heating belt (43).

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

10. The method for using the fluid flow and stability performance testing device according to claim 9, wherein: Including fluid stability performance test method and fluid flow performance test method, (1) Fluid stability performance test method, including the following process: (i) turning 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) In a mixing tank (1), a mixture of test sand and clean water is prepared with a sand ratio of 10%, and the mixture is stirred thoroughly according to the mass percentage. After the clean water and the test sand are fully mixed, a foaming agent is added, and the mixture is stirred again to fully mix the solution; (iii) opening the opening valve (2), starting the screw pump (4), regulating the liquid flow rate so that the liquid enters the liquid delivery pipe (25) of the foam generator (18) at the set flow rate, and simultaneously opening 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); (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 operate the coaxial forward and reverse rotation device (26). 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 disturbance of the fluid is increased by the flow turbulence ribs (40) on the rotating cylinder wall (22), preventing the experimental sand from settling at the bottom of the rotating cylinder wall (22), so that the liquid, gas and sand are fully mixed to generate sand-carrying foam; (v) adjusting the liquid and gas flow rates entering the foam generator (18) and controlling the gas-liquid ratio by using the displayed values ​​of the liquid flow meter (5) and the first gas flow meter (9); (vi) opening the first high-pressure stop valve (7), closing the second high-pressure stop valve (14), injecting the foam fluid into the simulated wellbore (19), and controlling the amount of the foam liquid entering the simulated wellbore (19) by the display of the foam flowmeter (6), then closing the first high-pressure stop valve (7), opening the second one-way valve (11), injecting the gas from the second gas cylinder (13) into the simulated wellbore (19), and controlling the amount of the gas entering the simulated wellbore (19) by the second gas flowmeter (12), and after the pressure in the simulated wellbore (19) is increased to 4 MPa, the high-definition camera (20) captures the experimental phenomena in the simulated wellbore (19) through the visual window (42), and records the experimental phenomena; (vii) opening the second high-pressure shut-off valve (14) to allow the solution to flow into the grit chamber (17); (viii) The solution enters the filter basket (52) through the liquid inlet pipe (54), and the filter basket (52) separates the sand (45) and the liquid (46). The sand is stored in the filter basket (52), and the liquid (46) is discharged through the drain valve (49). After the experiment is completed, the upper cover lock (50) is opened, the upper cover (47) is opened, and the filter basket (52) is lifted out by the handle (53) to clean the sand. (ix) Conduct a foam fluid stability test without sand, at 4 MPa and 60°C according to the above steps, and compare it with the foam stability test with sand, at 4 MPa and 60°C in the above steps to observe the changes in foam fluid stability under these experimental conditions. Similarly, conduct a multi-factor cross-test of foam fluid stability by varying the experimental sand, sand ratio, gas-liquid ratio, pressure and temperature; (2) Fluid flow performance test method, including the following process: (I) Ensure all valves are closed before testing; (II) In a mixing tank (1), a mixture of test sand and clean water is prepared to a sand ratio of 10%. The mixture is stirred according to the mass percentage. After being fully mixed, a foaming agent is added and stirred again until the foam volume ratio reaches 80%. After the mixture reaches the test standard, the test is carried out; (III) opening the opening valve (2), starting the screw pump (4), regulating the liquid flow rate so that the liquid enters the liquid delivery pipe (25) of the foam generator (18) at the set flow rate, and simultaneously opening the first one-way 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 transmit kinetic energy through the power transmission shaft (34), so that the coaxial forward and reverse rotation device (26) is operated, 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, and increases the disturbance of the fluid through the spoiler ribs (40) on the rotating cylinder wall (22), preventing the experimental sand from settling at the bottom of the rotating cylinder wall (22), so that the liquid, gas and sand are fully mixed to generate sand-carrying foam; (V) regulating the liquid and gas flow rates entering the foam generator (18) and controlling the gas-liquid ratio by operating the liquid flow meter (5) and the first gas flow meter (9); (VI) The difference from the fluid stability performance test is that the fluid flow performance test is carried out at normal temperature and pressure, so the second one-way valve (11) and the electric heating belt (43) are both in the closed state; (VII) opening the first high-pressure stop valve (7) and the second high-pressure stop valve (14), allowing the foam fluid to carry sand into the simulated wellbore (19), and using the high-definition camera (20) to capture experimental phenomena in the simulated wellbore (19) through the visual window (42), and recording the experimental phenomena; (VIII) The multiphase solution flows into the grit chamber (17) through the pipeline: After the multiphase solution enters the filter basket (52) through the liquid inlet pipe (54), the filter basket (52) separates the sand (45) and the liquid (46). The sand is stored in the filter basket (52), and the liquid (46) is discharged through the drain valve (49). After the experiment is completed, the upper cover lock (50) is opened, the upper cover (47) is opened, and the filter basket (52) is lifted out by the handle (53) to clean the sand. (IX) Referring to the above steps, by changing different sand ratios, the flow properties of the foam fluid under different sand ratios can be tested.

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