Measuring device and method for measuring rheological changes of oil displacement foam system in oil reservoir

Abstract

The present invention provides a measuring device and method for measuring the rheological changes of an oil displacement foam system in an oil reservoir, wherein the measuring device includes a foam generator and a metal tube; the foam outlet end of the foam generator can be connected to the inlet end of the metal tube in an on-off manner, and the metal tube is composed of at least two sections of equal-diameter tubes connected in series in sequence; the inner diameters of the at least two sections of equal-diameter tubes are different, and each section of the equal-diameter tubes is a hollow tube, or at least one section of the equal-diameter tubes is filled with equal-diameter particles; or the inner diameters of the each section of the equal-diameter tubes are the same, and at least one section of the equal-diameter tubes is filled with equal-diameter particles. The present invention can be used to simulate the rheological test of the oil displacement foam system in an environment of long-distance migration from an injection well to a production well in an oil reservoir, and is more conducive to the independent study of the rheological properties of the oil displacement foam system itself, with lower test efficiency and test error.

Description

Technical Field

[0001] The present invention relates to the field of oil and gas development, and in particular to a measuring device and method for measuring rheological changes of an oil displacement foam system in an oil reservoir. Background Art

[0002] In the petroleum industry, foam flooding technology is widely used in oilfield production. A flooding foam system is a composite system composed of gas, liquid, and surfactant. The foam increases the viscosity and flow resistance of the displacing phase, increasing the swept volume of the displacing fluid in porous media and providing excellent profile control capabilities. Combined with the surfactant's ability to reduce oil / water interfacial tension and capillary resistance experienced by oil droplets, it can significantly improve oil recovery.

[0003] The oil displacement effect of a foam system is affected by its rheological properties. The rheological properties of the foam can affect its permeability and diffusivity in the reservoir, which in turn affects the oil displacement effect. By testing the rheological properties of the foam system, we can guide the adjustment of the foam system's viscosity and stability, improve its distribution uniformity in the reservoir, and thus improve the oil displacement effect.

[0004] Existing rheological measurement devices primarily focus on measuring rheology at room temperature and pressure, and few are capable of simulating the high-temperature, high-pressure conditions found in oil reservoirs. Furthermore, due to the highly complex microstructure of porous reservoir media, where matrix, hydraulic fractures, and natural fractures coexist within the reservoir, the flow of flooding foam systems from injection wells to production wells involves foam migration, retention, coalescence, defoaming, and regeneration. Existing high-temperature, high-pressure rheological testing devices are unable to simulate the actual flow of foam within the reservoir, resulting in significant discrepancies between rheological test results and field application results. Summary of the Invention

[0005] The purpose of the present invention is to provide a measuring device and method for determining the rheological changes of an oil displacement foam system in an oil reservoir. The device and method can be used to simulate the rheological test of the oil displacement foam system in an environment of long-distance migration from an injection well to a production well in an oil reservoir, and are more conducive to the independent study of the rheological properties of the oil displacement foam system itself, with lower test efficiency and test error.

[0006] The purpose of the present invention can be achieved by adopting the following technical solutions:

[0007] The present invention provides a measuring device for measuring rheological changes of an oil displacement foam system in an oil reservoir, comprising a foam generator and a metal tube; the foam outlet end of the foam generator is connectable to the inlet end of the metal tube, and the metal tube is composed of at least two sections of equal-diameter tube bodies connected in series in sequence; the inner diameters of the at least two sections of equal-diameter tube bodies are different, and each section of the equal-diameter tube body is a hollow tube, or at least one section of the equal-diameter tube body is filled with equal-diameter particles; or the inner diameters of the equal-diameter tube bodies are the same, and at least one section of the equal-diameter tube body is filled with equal-diameter particles.

[0008] In a preferred embodiment of the present invention, the measuring device further includes a temperature-controlled base and a first foam collector; the outlet end of the metal tube is connected to the first foam collector through a corresponding pipeline, and the metal tube is arranged on the temperature-controlled base.

[0009] In a preferred embodiment of the present invention, the inner diameter of the constant diameter tube body is 0.15-1.0 mm, and the length is 1.5-4 m; the metal tube is in a coiled shape, and the granular material is quartz sand.

[0010] In a preferred embodiment of the present invention, filter screens are provided at both ends of the equal-diameter tube filled with equal-diameter particles.

[0011] In a preferred embodiment of the present invention, pressure measuring points are provided at both ends of the metal tube and at the connection between two adjacent sections of equal-diameter tubes, and a corresponding pressure sensor is provided at each pressure measuring point; a flow sensor is connected to the outlet end of the metal tube; the measuring device also includes a data acquisition and processing system, which is electrically connected to the pressure sensor and the flow sensor.

[0012] In a preferred embodiment of the present invention, the foam outlet end can be connected to the inlet end of the metal tube through a first pipeline and can be connected to the second foam collector through a second pipeline; a visual observation cabin is connected in series to the second pipeline, and a camera is arranged on the outside of the visual observation cabin, and the data acquisition and processing system is electrically connected to the camera.

[0013] In a preferred embodiment of the present invention, the measuring device also includes: a first intermediate container, which can be connected to the first inlet end of the foam generator in a disconnectable manner, and is used to transport foaming liquid into the foam generator; a second intermediate container, which can be connected to the second inlet end of the foam generator in a disconnectable manner, and is used to transport gas into the foam generator.

[0014] In a preferred embodiment of the present invention, the first intermediate container includes a first cylinder with a first piston provided therein, the first piston divides the interior of the first cylinder into a first upper chamber for holding foaming liquid and a first lower chamber for holding liquid; the first upper chamber is connected to the first inlet end through a first pipeline in a disconnectable manner, and the first lower chamber is connected to the first constant speed and constant pressure pump through a corresponding pipeline; the second intermediate container includes a second cylinder with a second piston provided therein, the second piston divides the interior of the second cylinder into a second upper chamber for holding gas and a second lower chamber for holding liquid; the second upper chamber is connected to the second inlet end through a second pipeline in a disconnectable manner, and the second lower chamber is connected to the second constant speed and constant pressure pump through a corresponding pipeline; the data acquisition and processing system is electrically connected to the first constant speed and constant pressure pump and the second constant speed and constant pressure pump.

[0015] In a preferred embodiment of the present invention, the foam generator includes a main cylinder with a movable piston inside, the movable piston divides the interior of the main cylinder into an upper auxiliary chamber for holding liquid and a lower mixing chamber, the upper auxiliary chamber is connected to a third constant speed and constant pressure pump through a third pipeline and can be connected on and off, the first inlet end, the second inlet end and the foam outlet end are all connected to the lower mixing chamber, and an agitator is provided in the lower mixing chamber.

[0016] The present invention also provides a method for measuring the rheological changes of an oil displacement foam system in an oil reservoir, comprising:

[0017] A foam generator is used to stir the test gas and the test foaming liquid to generate an oil displacement foam system;

[0018] Injecting the oil displacement foam system into a metal pipe; wherein the metal pipe is composed of at least two sections of equal-diameter pipes connected in series; the inner diameters of the at least two sections of equal-diameter pipes are different, and each section of the equal-diameter pipes is hollow, or at least one section of the equal-diameter pipes is filled with equal-diameter particles; or the inner diameters of the equal-diameter pipes are the same, and at least one section of the equal-diameter pipes is filled with equal-diameter particles;

[0019] Adjust the injection speed of the oil displacement foam system and detect the pressure data at both ends of each section of the equal-diameter pipe and the flow data at the outlet end of the metal pipe at different injection speeds;

[0020] The shear rate and viscosity of the oil displacement foam system in each section of the equal-diameter pipe at each moment are obtained according to the corresponding pressure data, flow rate data and injection speed at both ends of each section of the equal-diameter pipe.

[0021] As described above, the testing device and method of the present invention can be used to simulate the rheological test of the oil displacement foam system in the long-distance migration environment from the injection well to the production well in the oil reservoir. Each section of the equal-diameter tube body can provide a consistent flow space. During the flow of the foam oil displacement system in the equal-diameter tube body, it can be ensured that the rheological properties are only related to the properties of the oil displacement foam system itself, which is more conducive to the independent study of the rheological properties of the oil displacement foam system itself. Moreover, the inner diameters of the equal-diameter tube bodies can be the same or different. The equal-diameter tube bodies can all be hollow tubes, or at least part of the equal-diameter tube bodies can be filled with equal-diameter particles, which can be used to simulate the matrix and cracks of the oil reservoir; thus, the actual flow state of the foam oil displacement system in the oil reservoir can be more realistically simulated. Through the different designs of the metal tubes, the rheological test of the oil displacement foam system in the flow conditions of the reservoir matrix, crack to matrix, crack to matrix and then to crack can be simulated. The foam viscosity under multiple shear rates can also be tested at one time, which improves the test efficiency and reduces the test error. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The following drawings are only intended to illustrate and explain the present invention, and are not intended to limit the scope of the present invention.

[0023] in:

[0024] Figure 1 : A schematic structural diagram of a measuring device for measuring rheological changes of an oil displacement foam system in an oil reservoir provided by the present invention.

[0025] Figure 2 : A schematic structural diagram of the metal tube provided by the present invention.

[0026] Figure 3 : Another structural schematic diagram of the metal tube provided by the present invention.

[0027] Figure 4 : Another structural schematic diagram of the metal tube provided by the present invention.

[0028] Figure 5 : Another structural schematic diagram of the metal tube provided by the present invention.

[0029] Figure 6 : Schematic diagram of the shear rate-viscosity rheological curve of the oil displacement foam system obtained in the present invention.

[0030] Description of Figure Numbers:

[0031] 1. Foam generator; 11. Three-way pipe; 12. First pipeline; 121. First on-off valve; 13. Second pipeline; 131. Second on-off valve; 132. Visual observation cabin; 14. Second foam collector; 15. Moving piston; 16. Third pipeline; 161. Third valve; 17. Third constant-speed and constant-pressure pump; 18. Agitator; 19. Motor;

[0032] 2. Metal tube; 21. Constant diameter tube; 211. Hollow tube; 22. Constant diameter particles; 23. Pressure measuring point; 231. Pressure sensor; 24. Flow sensor; 25. First foam collector;

[0033] 3. Temperature control base;

[0034] 4. Data acquisition and processing system;

[0035] 5. Camera;

[0036] 6. First intermediate container; 61. First piston; 62. First pipeline; 621. First valve; 63. First constant speed and constant pressure pump;

[0037] 7. Second intermediate container; 71. Second piston; 72. Second pipeline; 721. Second valve; 73. Second constant speed and constant pressure pump. DETAILED DESCRIPTION

[0038] In order to have a clearer understanding of the technical features, purposes and effects of the present invention, specific embodiments of the present invention are now described with reference to the accompanying drawings.

[0039] like Figures 1 to 6 As shown, the present application provides a measuring device for measuring the rheological changes of an oil displacement foam system in an oil reservoir, comprising a foam generator 1 and a metal tube 2; the foam outlet end of the foam generator 1 can be connected to the inlet end of the metal tube 2 in an on-off manner, and the metal tube 2 is composed of at least two sections of equal-diameter tube bodies 21 connected in series in sequence; the inner diameters of at least two sections of equal-diameter tube bodies 21 are different, and each section of the equal-diameter tube body 21 is a hollow tube 211, or at least one section of the equal-diameter tube body 21 is filled with equal-diameter particles 22; or, the inner diameters of each section of the equal-diameter tube body 21 are the same, and at least one section of the equal-diameter tube body 21 is filled with equal-diameter particles 22.

[0040] Among them, the metal tube 2 is composed of at least two sections of equal-diameter tubes 21 connected in series in sequence, the inner diameter of each section of the equal-diameter tube 21 is uniform, and the equal-diameter tube 21 is a single tube extending in a long strip shape. The equal-diameter tube 21 itself is a single tube with a uniform inner diameter, and there are no other complex pipelines such as bifurcations; when the sections of the equal-diameter tube 21 are connected, there are no bifurcations or other complex connection methods at each connection; for a single section of the equal-diameter tube 21, it is a hollow tube 211 (that is, the interior is hollow and not filled with particles), or it is filled with equal-diameter particles 22 (that is, particles with uniform particle size) to ensure that the internal medium of the single section of the equal-diameter tube 21 is uniform; in this way, when the oil-displacement foam system generated by the foam generator 1 flows into and out of the sections of the equal-diameter tube 21 of the metal tube 2, when the foam-displacement system flows in each section of the equal-diameter tube 21, the equal-diameter tube 21 can provide a consistent flow space for the foam-displacement system.

[0041] It can be understood that the particle sizes of the equal-diameter particles 22 filled in different sections of the equal-diameter tube body 21 can be the same or different; but the particle size of the equal-diameter particles 22 inside each section of the equal-diameter tube body 21 is uniform.

[0042] When the oil-displacement foam system flows in an actual oil reservoir, its rheological properties are related to the properties of the oil-displacement foam system itself on the one hand, and to the complexity of the pores and fractures of the oil reservoir itself on the other hand; the design of the metal tube 2 in this application can provide a consistent flow space in each section of the equal-diameter tube body 21. If there is a change in the rheological properties during the flow of the foam oil-displacement system in the equal-diameter tube body 21, it is caused by a change in the properties of the fluid itself.

[0043] The above metal tube 2 can be designed in the following ways:

[0044] (1) At least two sections of the equal-diameter tube body 21 have different inner diameters, and each section of the equal-diameter tube body 21 is a hollow tube 211;

[0045] (2) The inner diameters of at least two sections of the equal-diameter tube body 21 are different, and at least one section of the equal-diameter tube body 21 is filled with equal-diameter particles 22;

[0046] (3) The inner diameters of the various sections of the equal-diameter tube body 21 are the same, and at least one section of the equal-diameter tube body 21 is filled with equal-diameter particles 22 .

[0047] Actual oil reservoirs have highly complex microstructures, and fluid migration pathways within them include two major forms: matrix and fractures. The matrix can be further divided into two forms, namely, voids and throats, depending on pore size. Hollow tubes 211, which are equal-diameter pipe bodies 21, can be used to simulate fracture migration pathways within an oil reservoir. Equal-diameter pipe bodies 21 filled with equal-diameter particles 22 can be used to simulate matrix migration pathways (including pore migration pathways and throat migration pathways). The specific number of equal-diameter pipe bodies 21 and their connection order can be determined based on actual testing needs.

[0048] For example, Figure 2 In the embodiment, the metal tube 2 includes three sections of equal-diameter tubes 21 sequentially connected from its inlet end to its outlet end. The inner diameters of the three sections of equal-diameter tubes 21 are different and increase from the inlet end to the outlet end of the metal tube 2. This can simulate the flow of the oil displacement foam system under different fractures in the reservoir. Figure 3 In an optional example, the entire metal tube 2 is filled with particles 22 of equal diameter, which can simulate the flow of the oil displacement foam system in the reservoir matrix; Figure 4In the figure, the metal tube 2 includes two sections of equal-diameter tubes 21 connected in series from its inlet end to its outlet end. The equal-diameter tube 21 near the inlet end is a hollow tube 211, and the other equal-diameter tube 21 is filled with equal-diameter particles 22, which can simulate the flow of the oil displacement foam system from the fracture to the matrix in the reservoir. Figure 5 In the figure, the metal tube 2 includes three sections of equal-diameter tube bodies 21 connected in series from its inlet end to the outlet end. The inner diameters of the three sections of equal-diameter tube bodies 21 are the same. The equal-diameter tube body 21 in the middle is filled with equal-diameter particles 22, which can simulate the flow of the oil displacement foam system from the fracture to the matrix and then to the fracture in the oil reservoir.

[0049] Thus, the measuring device in this embodiment can be used to simulate the rheological properties test of the oil displacement foam system in the long-distance migration environment from the injection well to the production well in the oil reservoir (corresponding to the flow process of the foam oil displacement system from the inlet end to the outlet end of the metal tube 2). Each section of the equal-diameter tube body 21 can provide a consistent flow space. During the flow of the foam oil displacement system in the equal-diameter tube body 21, it can be ensured that the rheological properties are only related to the properties of the oil displacement foam system itself, which is more conducive to the separate study of the rheological properties of the oil displacement foam system itself. Moreover, the inner diameters of the equal-diameter tube bodies 21 can be the same or different. Each equal-diameter tube body 21 can be a hollow tube 211, or at least part of the equal-diameter tube body 21 can be filled with equal-diameter particles 22, which can be used to simulate the matrix and cracks of the oil reservoir; thereby, the real flow state of the foam oil displacement system in the oil reservoir can be more realistically simulated. Through different designs of the metal tube 2, the rheological test of the oil displacement foam system in the flow conditions of reservoir matrix, fracture to matrix, fracture to matrix and then to fracture can be simulated. The foam viscosity at multiple shear rates can also be tested at one time, which improves the test efficiency and reduces the test error.

[0050] In a specific implementation, the above-mentioned measuring device also includes a temperature control base 3 and a first foam collector 25 ; the outlet end of the metal tube 2 is connected to the first foam collector 25 through a corresponding pipeline, and the metal tube 2 is arranged on the temperature control base 3 .

[0051] The metal tube 2 is generally placed horizontally on a temperature-controlled base 3. The temperature-controlled base 3 can be set to a temperature according to experimental needs, heat the metal tube 2, maintain a constant temperature, and better simulate the temperature of an actual oil reservoir. The metal tube 2 is preferably in a coiled shape to save more space. The above-mentioned equal-diameter particles 22 can be made of quartz sand or copper powder, etc., and quartz sand is more preferably used, which is closer to the actual underground oil reservoir and has low cost; the specific filling quartz sand particle size can be selected according to the particle size distribution of the test reservoir rock. The material of the metal tube 2 needs to be a pressure-resistant material. For example, in this embodiment, the metal tube 2 is a stainless steel tube.

[0052] The inner diameter of each section of the equal-diameter tube 21 is preferably 0.15-1.0 mm, and the length is preferably 1.5-4 m; so that each section of the equal-diameter tube 21 forms a slender tube, which is thin and long, and can ensure that the pressure difference at both ends of each section of the equal-diameter tube 21 is large, which is more conducive to pressure measurement and ensures smaller measurement errors. The specific inner diameter and length of each section of the equal-diameter tube 21 are determined according to experimental needs, for example Figure 2 The three sections of equal-diameter tube bodies 21 in the metal tube 2 shown in the figure have inner diameters of 0.15-0.3 mm, 0.5-0.7 mm and 0.8 mm-1.0 mm from the inlet end to the outlet end, and lengths of 1.5-2.0 m, 2.0-3.0 m and 3.0-4.0 m, respectively.

[0053] In actual applications, a filter screen is provided at both ends of the equal-diameter tube body 21 filled with equal-diameter particles 22. The aperture of the filter screen should be smaller than the particle size of the equal-diameter particles 22 in the equal-diameter tube body 21 to prevent the equal-diameter particles 22 in the equal-diameter tube body 21 from entering the adjacent tube body.

[0054] Furthermore, pressure measuring points 23 are provided at both ends of the metal tube 2 and at the connection between two adjacent sections of the equal-diameter tube body 21, and a corresponding pressure sensor 231 is provided at each pressure measuring point 23; a flow sensor 24 is connected to the outlet end of the metal tube 2; the measuring device also includes a data acquisition and processing system 4, which is electrically connected to the pressure sensor 231 and the flow sensor 24 to facilitate recording the pressure and flow at both ends of the equal-diameter tube body 21.

[0055] The data acquisition and processing system 4 can collect the pressure data detected by each pressure sensor 231 and the flow data detected by the flow sensor 24, and can obtain the shear rate and viscosity of the oil-displacing foam system in each section of the equal-diameter tube body 21 at each moment based on the pressure data and flow data corresponding to the two ends of each section of the equal-diameter tube body 21 and the injection speed of the foam generator 1 into the metal tube 2, so as to facilitate experimental personnel to conduct relevant research on the properties of the oil-displacing foam system.

[0056] Generally, to facilitate processing and installation, a tee is connected between two adjacent equal-diameter tubes 21. The two ends of the tee are connected to the equal-diameter tubes 21 on either side, and the other end of the tee serves as a pressure measuring point 23 connected to a corresponding pressure sensor 231. Providing pressure measuring points 23 at both ends of each equal-diameter tube 21 facilitates simultaneous measurement of foam viscosities at multiple shear rates.

[0057] The above-mentioned foam generator 1 is mainly used to generate an oil-displacing foam system. In order to ensure that the foam generated by the foam generator 1 is stable before being injected into the metal tube 2, the foam outlet end can be connected to the inlet end of the metal tube 2 through the first pipeline 12, and can be connected to the second foam collector 14 through the second pipeline 13; a visual observation cabin 132 is connected in series on the second pipeline 13, and a camera 5 is arranged on the outside of the visual observation cabin 132, and the data acquisition and processing system 4 is electrically connected to the camera 5 to facilitate real-time observation of the foam state.

[0058] Generally, for ease of connection, the foam outlet is connected to a three-way pipe 11 via corresponding pipelines. The other two ports of the three-way pipe 11 are connected to a first pipe 12 and a second pipe 13, respectively. A first on-off valve 121 is provided on the first pipe 12; a second on-off valve 131 and a visual observation cabin 132 are provided on the second pipe 13. The visual observation cabin 132 is located near the second foam collector 14. The first foam collector 25 and the second foam collector 14 can be, for example, liquid collection bottles. The camera 5 can be a high-definition camera. The visual observation cabin 132 includes a cabin body with an opening on the central side wall of the cabin body and is sealed with aluminosilicate glass. The interior of the visual observation cabin 132 can be observed through the camera 5.

[0059] During use, the oil displacement foam system generated by the foam generator 1 is introduced into the visual observation cabin 132 to observe the foaming state of the foam in real time. After the foam generation is stable, the oil displacement foam system is introduced into the metal pipe 2.

[0060] In order to facilitate the preparation of oil displacement foam system, the measuring device also includes:

[0061] a first intermediate container 6, which is openably and disconnectably connected to the first inlet end of the foam generator 1 and is used to transport the foaming liquid into the foam generator 1;

[0062] The second intermediate container 7 is connected to the second inlet end of the foam generator 1 in an on-off manner and is used to transport gas into the foam generator 1 .

[0063] The oil displacement foam system is a composite system composed of gas, liquid and surfactant, and the foaming liquid here refers to a mixture of liquid and surfactant.

[0064] Specifically, the first intermediate container 6 includes a first cylinder with a first piston 61 provided therein, and the first piston 61 divides the interior of the first cylinder into a first upper chamber for holding foaming liquid and a first lower chamber for holding liquid; the first upper chamber is connected to the first inlet end in a disconnectable manner through a first pipeline 62, and the first lower chamber is connected to the first constant speed and constant pressure pump 63 through a corresponding pipeline; the second intermediate container 7 includes a second cylinder with a second piston 71 provided therein, and the second piston 71 divides the interior of the second cylinder into a second upper chamber for holding gas and a second lower chamber for holding liquid; the second upper chamber is connected to the second inlet end in a disconnectable manner through a second pipeline 72, and the second lower chamber is connected to the second constant speed and constant pressure pump 73 through a corresponding pipeline; the data acquisition and processing system 4 is electrically connected to the first constant speed and constant pressure pump 63 and the second constant speed and constant pressure pump 73.

[0065] The foam generator 1 includes a main cylinder with a movable piston 15 inside. The movable piston 15 divides the interior of the main cylinder into an upper auxiliary chamber for holding liquid and a lower mixing chamber. The upper auxiliary chamber is connected to a third constant speed and constant pressure pump 17 through a third pipeline 16. The first inlet end, the second inlet end and the foam outlet end are all connected to the lower mixing chamber, and an agitator 18 (such as a stirring paddle) is provided in the lower mixing chamber.

[0066] Reference Figure 1 A first valve 621 is provided on the first pipeline 62, a second valve 721 is provided on the second pipeline 72, and a third valve 161 is provided on the third pipeline 16. The data acquisition and processing system 4 is electrically connected to the first on-off valve 121, the second on-off valve 131, the first valve 621, the second valve 721, and the third valve 161 to control the on-off of each location. The first intermediate container 6 and the second intermediate container 7 both have a piston in the middle, with the fluid to be injected in the upper part and liquid (e.g., distilled water) in the lower part. Both are connected to a pump. A constant speed and constant pressure pump is used to squeeze the piston with distilled water, causing the piston to move upward, thereby delivering the fluid to be injected, allowing for more accurate control of the metered injection volume.

[0067] The foam generator 1 also includes a base connected to the bottom of the main cylinder. A motor 19 is housed within the base and connected to the agitator 18 to drive the agitator 18. A data acquisition and processing system 4 is connected to the motor 19 to control its operation. The foam generator 1 also features a central piston with a liquid (e.g., distilled water) located above it, connected to a constant-speed, constant-pressure pump, enabling more accurate control of metered injection volume.

[0068] Furthermore, the present application also provides a method for measuring the rheological changes of an oil displacement foam system in an oil reservoir, comprising:

[0069] The test gas and the test foaming liquid are stirred by the foam generator 1 to generate an oil displacement foam system;

[0070] The oil displacement foam system is injected into the metal pipe 2; wherein the metal pipe 2 is composed of at least two sections of equal-diameter pipes 21 connected in series; the inner diameters of the at least two sections of equal-diameter pipes 21 are different, and each section of the equal-diameter pipes 21 is a hollow pipe 211, or at least one section of the equal-diameter pipes 21 is filled with equal-diameter particles 22; or the inner diameters of the equal-diameter pipes 21 are the same, and at least one section of the equal-diameter pipes 21 is filled with equal-diameter particles 22;

[0071] Adjust the injection speed of the oil displacement foam system and detect the pressure data at both ends of each section of the equal-diameter pipe 21 and the flow data at the outlet end of the metal pipe 2 at different injection speeds;

[0072] According to the pressure data, flow data and injection speed corresponding to both ends of each section of the equal-diameter tube body 21, the shear rate and viscosity of the oil displacement foam system in each section of the equal-diameter tube body 21 at each moment are obtained, and the rheological curve of the shear rate and viscosity can also be obtained.

[0073] The measurement method can specifically be performed using the above-mentioned measuring device, and has the same advantages as the measuring device, which will not be described in detail here.

[0074] Furthermore, stirring the test gas and the test foaming liquid by using the foam generator 1 specifically includes:

[0075] The test gas and the test foaming liquid are injected into the foam generator 1 at the same time, and the injection speed of the test gas and the test foaming liquid is adjusted according to the test requirements so as to adjust the gas-liquid ratio.

[0076] Before the oil displacement foam system is injected into the metal pipe 2, the following steps are also included:

[0077] The oil displacement foam system is injected into the visual observation cabin 132, and the image in the visual observation cabin 132 is collected by the camera 5. The foaming state of the foam is observed in real time through the data acquisition and processing system 4. After the foam generation is stable, the foam is introduced into the metal pipe 2.

[0078] Furthermore, the viscosity and shear rate of the oil displacement foam system in the constant diameter pipe body 21 at each moment can be calculated by the following formula:

[0079] For a tube 21 of equal diameter filled with particles 22 of equal diameter, the viscosity μ of the foam can be calculated by the following Darcy formula (1-1), and the shear rate γ of the foam can be calculated by the following formula (1-2):

[0080]

[0081] γ=d(Q / ΦA) / dr p (1-2)

[0082] Wherein, μ represents the viscosity of the foam; k represents the permeability of the corresponding equal-diameter tube 21, D; A represents the cross-sectional area of ​​the corresponding equal-diameter tube 21, cm 2 ; L represents the length of the corresponding equal-diameter tube 21, cm; Q represents the flow rate of the corresponding equal-diameter tube 21, cm 3 / s; △P represents the pressure difference between the two ends of the corresponding equal-diameter tube 21, MPa;

[0083] γ represents the shear rate of the foam; φ represents the porosity of the equal-diameter particles 22 filled in the corresponding equal-diameter tube 21, %; r p represents the average pore radius of the equal-diameter particles 22 filled in the corresponding equal-diameter tube 21, in cm.

[0084] For the hollow tube 211, the viscosity μ of the foam can be calculated by the following formula (2-1), and the shear rate γ of the foam can be calculated by the following formula (2-2):

[0085] μ=Kγ n-1 (2-1)

[0086]

[0087] n=dlg(DΔP / 4L) / dlg(8u / D) (3-1)

[0088] u=4Q / πD 2 (3-2)

[0089]

[0090] Wherein, μ represents the viscosity of the foam; γ represents the shear rate of the foam; n represents the rheological index, which can be calculated by the above formula (3-1); u represents the flow rate, which can be calculated by the above formula (3-2); K represents the consistency coefficient, which can be calculated by the above formula (3-3); Q represents the flow rate of the corresponding equal diameter pipe 21, cm 3 / s; r represents the radius of the corresponding equal-diameter tube 21; D represents the diameter of the corresponding equal-diameter tube 21; ΔP represents the pressure difference across the corresponding equal-diameter tube 21, in MPa; L represents the length of the corresponding equal-diameter tube 21, in cm; K' represents the intercept of the relationship curve between DΔP / 4L and 8u / D on the ordinate axis in a double logarithmic coordinate system.

[0091] It should be noted that the flow rate Q of the corresponding constant-diameter tube 21 is generally based on the flow rate data detected by the flow sensor 24 connected to the outlet end of the metal tube 2. Since the oil displacement foam system contains both gas and liquid, the flow rate at each location in the tube is the same for the liquid. However, for the gas, due to its compressibility, the flow rate will vary slightly when the pressure at each location in the tube is different. Therefore, during actual calculations, Boyle's law can also be used to correct the flow rate data detected by the flow sensor 24, and the resulting correction value is used as the flow rate Q of the corresponding constant-diameter tube 21.

[0092] To better understand the measurement method of this embodiment, a specific embodiment is used as an example below. The measurement method includes:

[0093] Step 1: Connect the measuring device and check its sealing. Open the temperature control base 3 and the data acquisition and processing system 4 for debugging and calibration. Set the temperature of the temperature control base 3 to the test temperature and keep it constant for more than 30 minutes.

[0094] Step 2: Inject the foaming liquid into the first intermediate container 6 and the gas into the second intermediate container 7. Start the agitator 18 in the foam generator 1. After the speed stabilizes, start the first constant-speed and constant-pressure pump 63 and the second constant-speed and constant-pressure pump 73. Open the first valve 621 and the second valve 721 to simultaneously inject the gas and foaming liquid into the foam generator 1. According to test requirements, the injection speed of the gas and foaming liquid is controlled by adjusting the pump speed of the first constant-speed and constant-pressure pump 63 and the second constant-speed and constant-pressure pump 73 to adjust the gas-liquid ratio.

[0095] Step 3: Start the third constant speed and constant pressure pump 17, open the third valve 161 and the second on-off valve 131, close the first on-off valve 121, and introduce the foam liquid into the visual observation cabin 132 by controlling the height of the piston in the foam generator 1. The foaming state is observed in real time through the data acquisition and processing system 4. After the foam generation stabilizes, close the second on-off valve 131, open the first on-off valve 121, and introduce the foam into the metal tube 2;

[0096] Step 4: Adjust the foam injection speed by adjusting the pump speed of the third constant speed and constant pressure pump 17, and measure the pressure at both ends of each section of the equal diameter tube 21 in the metal tube 2 and the flow rate at the outlet end of the metal tube 2 at different foam injection speeds;

[0097] Step 5: Based on the injection speed, flow rate data and the corresponding pressure data at both ends of each section of the equal-diameter tube body 21, calculate the shear rate γ and viscosity μ of the oil-displacing foam system in each section of the equal-diameter tube body 21 at each moment, and draw the shear rate-viscosity rheological curve of the oil-displacing foam system in each section of the equal-diameter tube body 21.

[0098] For example, the rheological properties of the oil displacement foam system YFG812 used in an oil field were tested using the above-mentioned measuring device. The gas was nitrogen, the gas-liquid ratio was 2:1, and the test temperature was 45°C, simulating the reservoir temperature. Figure 4 The metal tube 2 simulating crack to matrix flow was subjected to rheological test, and the rheological curve obtained by the test was as shown in FIG. Figure 6 shown.

[0099] In summary, the testing device and method in this embodiment is a measurement method and device that can simulate the rheological changes of the oil-displacement foam system during migration from the injection well to the recovery well in the oil reservoir. By adjusting the diameter of the different sections of the equal-diameter tube body 21 in the metal tube 2 and the changes in the sand filling particle size, the changes in pores, throats, and cracks in the reservoir can be simulated; the foam properties under multiple shear rates can be tested at one time (by adjusting the inner diameter of the metal tube 2); the rheological test of the oil-displacement foam system under different reservoir temperatures and pressures can be simulated; the rheological test of foam generated by different gases and foaming liquids can be simulated; the foam viscosity under multiple shear rates can be tested at one time to improve the test efficiency; the rheological test of the oil-displacement foam system under the long-distance migration environment from the injection well to the production well can be simulated; the rheological test of the oil-displacement foam system in the flow conditions of the reservoir matrix, crack to matrix, crack to matrix and then to crack can be simulated.

[0100] It should be noted that the testing device and method in this embodiment can be applied to any oil displacement foam system, such as a carbon dioxide foam system, a nitrogen foam system or an air foam system.

[0101] The above is only an illustrative embodiment of the present invention and is not intended to limit the scope of the present invention. Any equivalent changes and modifications made by those skilled in the art without departing from the concept and principle of the present invention should fall within the scope of protection of the present invention.

Claims

1. A measuring device for measuring rheological changes of an oil displacement foam system in an oil reservoir, characterized in that: Used to simulate the rheological properties of the long-distance migration environment between the injection well and the production well in the oil displacement foam system. The measuring device includes a foam generator, a metal tube, a temperature control base and a data acquisition and processing system; The foam outlet end of the foam generator can be connected to the inlet end of the metal tube in an on-off manner. The metal tube is made of a pressure-resistant material and is composed of at least two sections of equal-diameter tubes connected in series in sequence. The inner diameter of the equal-diameter tube is 0.15-1.0 mm and the length is 1.5-4 m. The inner diameters of at least two sections of the equal-diameter tube are different, and at least one section of the equal-diameter tube is filled with equal-diameter particles. Alternatively, the inner diameters of the equal-diameter tubes are the same, and at least one section of the equal-diameter tube is filled with equal-diameter particles. When the equal-diameter tube is a hollow tube, it can be used to simulate the fracture migration channel of the oil reservoir. When the equal-diameter tube is filled with equal-diameter particles, it can be used to simulate the matrix migration channel of the oil reservoir. The metal tube can be used to simulate the flow of the oil displacement foam system in the matrix of the oil reservoir, or can be used to simulate the flow of the oil displacement foam system from the fracture to the matrix and / or from the matrix to the fracture in the oil reservoir. The metal tube is coiled and placed horizontally on the temperature control base; pressure measuring points are provided at both ends of the metal tube and at the connection between two adjacent sections of equal-diameter tubes, and a corresponding pressure sensor is provided at each pressure measuring point; a flow sensor is connected to the outlet end of the metal tube; and the data acquisition and processing system is electrically connected to the pressure sensor and the flow sensor.

2. The measuring device for measuring rheological changes of an oil displacement foam system in an oil reservoir as claimed in claim 1, wherein: The measuring device further comprises a first foam collector; The outlet end of the metal tube is connected to the first foam collector through a corresponding pipeline.

3. The measuring device for measuring rheological changes of an oil displacement foam system in an oil reservoir as claimed in claim 1, wherein: The particulate matter is quartz sand.

4. The measuring device for measuring rheological changes of an oil displacement foam system in an oil reservoir as claimed in claim 1, wherein: Filter screens are provided at both ends of the equal-diameter tube body filled with the equal-diameter particles.

5. The measuring device for measuring rheological changes of an oil displacement foam system in an oil reservoir as claimed in claim 1, wherein: The foam outlet end is connected to the inlet end of the metal tube through a first pipeline in a disconnectable manner, and is connected to the second foam collector through a second pipeline in a disconnectable manner; a visual observation cabin is connected in series to the second pipeline, and a camera is arranged outside the visual observation cabin, and the data acquisition and processing system is electrically connected to the camera.

6. The measuring device for measuring rheological changes of an oil displacement foam system in an oil reservoir as claimed in claim 5, wherein: The measuring device further comprises: a first intermediate container, connected to the first inlet end of the foam generator in an on-off manner and used for conveying foaming liquid into the foam generator; The second intermediate container is connected to the second inlet end of the foam generator in an on-off manner and is used to transport gas into the foam generator.

7. The measuring device for measuring rheological changes of an oil displacement foam system in an oil reservoir as claimed in claim 6, wherein: The first intermediate container includes a first cylinder with a first piston disposed therein, the first piston dividing the interior of the first cylinder into a first upper chamber for containing foaming liquid and a first lower chamber for containing liquid; the first upper chamber is connected to the first inlet end via a first pipeline in a removable manner, and the first lower chamber is connected to a first constant speed and constant pressure pump via a corresponding pipeline; The second intermediate container includes a second cylinder having a second piston therein, the second piston dividing the interior of the second cylinder into a second upper chamber for containing gas and a second lower chamber for containing liquid; the second upper chamber is connected to the second inlet end via a second pipeline in a removable manner, and the second lower chamber is connected to a second constant speed and constant pressure pump via a corresponding pipeline; The data acquisition and processing system is electrically connected to both the first constant-speed and constant-pressure pump and the second constant-speed and constant-pressure pump.

8. The measuring device for measuring rheological changes of an oil displacement foam system in an oil reservoir as claimed in claim 6, wherein: The foam generator includes a main cylinder with a movable piston inside, and the movable piston divides the interior of the main cylinder into an upper auxiliary chamber for holding liquid and a lower mixing chamber. The upper auxiliary chamber is connected to a third constant speed and constant pressure pump through a third pipeline in a switchable manner. The first inlet end, the second inlet end and the foam outlet end are all connected to the lower mixing chamber, and an agitator is provided in the lower mixing chamber.

9. A method for measuring rheological changes of an oil displacement foam system in an oil reservoir, characterized in that: include: A foam generator is used to stir the test gas and the test foaming liquid to generate an oil displacement foam system; The oil displacement foam system is injected into a coiled metal tube placed horizontally on a temperature-controlled base; wherein the metal tube is composed of at least two sections of equal-diameter tubes connected in series; the inner diameter of the equal-diameter tubes is 0.15-1.0 mm and the length is 1.5-4 m; at least two sections of the equal-diameter tubes have different inner diameters, and at least one section of the equal-diameter tubes is filled with equal-diameter particles; or, the inner diameters of the equal-diameter tubes are the same, and at least one section of the equal-diameter tubes is filled with equal-diameter particles; Adjusting the injection speed of the oil displacement foam system, detecting the pressure data at both ends of each section of the equal-diameter pipe body and the flow rate data at the outlet end of the metal pipe at different injection speeds; Obtaining the shear rate and viscosity of the oil displacement foam system in each section of the equal-diameter pipe at each moment based on the corresponding pressure data at both ends of each section of the equal-diameter pipe, the flow rate data, and the injection speed; For a tube of equal diameter filled with particles of equal diameter, the foam viscosity μ and the foam shear rate γ are calculated by the following formulas: γ=d(Q / ΦA) / dr p Where μ represents the viscosity of the foam; k represents the permeability of the corresponding equal-diameter tube, D; A represents the cross-sectional area of ​​the corresponding equal-diameter tube, cm 2 ; L represents the length of the corresponding equal-diameter pipe, cm; Q represents the flow rate of the corresponding equal-diameter pipe, cm 3 / s; △P represents the pressure difference between the two ends of the corresponding equal-diameter pipe, MPa; γ represents the shear rate of the foam; φ represents the porosity of the equal-diameter particles filled in the corresponding equal-diameter tube, %; r p Indicates the average pore radius of the equal-diameter particles filled in the corresponding equal-diameter tube, cm; For a hollow tube with equal diameter, the foam viscosity μ and the foam shear rate γ are calculated by the following formulas: μ=Kγ n-1 n=dlg(DΔP / 4L) / dlg(8u / D) u=4Q / πD 2 Wherein, μ represents the viscosity of the foam; γ represents the shear rate of the foam; n represents the rheological index; u represents the flow rate; K represents the consistency coefficient; Q represents the flow rate of the corresponding equal diameter pipe, cm 3 / s; r represents the radius of the corresponding equal-diameter tube; D represents the diameter of the corresponding equal-diameter tube; △P represents the pressure difference between the two ends of the corresponding equal-diameter tube, MPa; L represents the length of the corresponding equal-diameter tube, in cm; K' represents the intercept of the relationship curve between DΔP / 4L and 8u / D on the ordinate axis in the double logarithmic coordinate system.

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