Physical simulation device and quantitative measurement method for interlayer channeling in sand-gravel mixed layer

Abstract

The present application belongs to the field of oil exploitation, and discloses a sand-gravel mixed layer interlayer channeling physical simulation device and a quantitative measurement method. The device comprises a sand-gravel mixed layer core, which is formed by stacking a sandstone layer core and a conglomerate layer core upside down; the sand-gravel mixed layer core comprises one injection end and two production ends for realizing combined injection and separate production; the injection end and the production end are provided with a non-permeable physical barrier at the junction of the sand-gravel mixed layer; the upper and lower walls of the sand-gravel mixed layer core are respectively provided with a first pressure measuring point and a second pressure measuring point corresponding to the ends of the physical barrier, for calculating the liquid absorption of the sand and gravel layers by measuring the pressure values and using Darcy's law; the two production ends are respectively connected to measuring cylinders for collecting and measuring the liquid production of the sand and gravel layers. The present application can simulate and analyze the channeling law and influencing factors of fluid in the sand-gravel mixed layer through the physical simulation device, and provide an experimental basis for the optimization design of field sand-gravel mixed layer fluid channeling and chemical flooding injection parameters.

Description

Technical Field

[0001] This invention belongs to the field of oil extraction, specifically relating to a physical simulation device and quantitative measurement method for interlayer flow in mixed sand and gravel layers. Background Technology

[0002] Xinjiang Oilfield is a large oilfield with conglomerate as its main oil and gas reservoir. After more than 10 years of laboratory experiments and field practice, Xinjiang Oilfield has initially formed the theory and technology for chemical flooding development of sandstone and conglomerate reservoirs. However, during development, due to the presence of conglomerate and sandstone layers at the bottom of the target formation, and the lack of effective interlayers between them, complex interlayer channeling phenomena occur during the injection of the chemical flooding system. Among them, the conglomerate reservoir is not the main target formation due to its complex pores, poor connectivity, and low remaining oil potential. However, in the general injection and production process, the results of fluid intake and production profile tests show that the conglomerate formation can absorb a large amount of injected fluid, and the injected fluid exhibits inefficient / ineffective circulation, which seriously affects the recovery rate of the target block. Therefore, it is urgent to carry out technical research on the unique reservoir structure of sandstone-conglomerate mixed formations and the interlayer channeling law of chemical flooding fluids to meet the needs of the widespread application of chemical flooding in sandstone-conglomerate mixed formations.

[0003] In the prior art, patent document CN103498669A provides a quantitative method for determining the interlayer flow rate of heterogeneous core models. This method compares the produced oil volume of each single-layer model with the oil saturation of each single-layer model obtained by CT scanning to analyze the interlayer flow rate of heterogeneous core models. This patent addresses the problem of dynamic distribution and stratified measurement of oil saturation within multi-layer cores during water-drive oil recovery experiments in heterogeneous models within layers. However, in implementing the technical solution of this application, the inventors of this application found that the technical solution of this patent has at least the following two problems: (1) it does not focus on the flow pattern of injected fluid between layers, but only on the change in oil saturation; (2) the CT scanning operation is complex and can only scan very small core units, resulting in a large error.

[0004] Patent document CN107389396A discloses a method for preparing and testing intra-layer heterogeneous cores for separate injection and extraction. First, the required amounts of quartz sand and epoxy resin for preparing high, medium, and low permeability layers of the designed size are weighed and mixed evenly. Then, insulating bakelite boards are placed along the length of the end faces of the lower, middle, and upper mixed sand layers, and these are placed in metal molds, leveled, pressurized, and dried. Next, the core end caps are bonded together. A layer of thickened but uncured epoxy resin is then applied to the remaining surface of the core and allowed to dry naturally. Finally, the core with the bonded end caps is placed in a wooden mold and cast as a whole using epoxy resin. After curing, an intra-layer heterogeneous core capable of separate injection and extraction is formed. This patent allows for the study of intra-layer heterogeneous flow patterns, and the process is simple to operate. However, in the process of implementing the technical solution of the present application, the inventors of this application found that the technical solution of the patent has at least the following two problems: (1) the separate injection and separate mining is inconsistent with the general injection and separate mining of the mine; (2) its core uses a single quartz sand and does not consider the influence of different lithologies on interlayer flow. Summary of the Invention

[0005] This invention addresses the prominent problem of interlayer crossflow and unclear crossflow mechanisms in sand-gravel mixed reservoirs in Xinjiang oilfields. It provides a physical simulation device and quantitative measurement method for interlayer crossflow in sand-gravel mixed reservoirs. Through unique core fabrication technology, a heterogeneous core model of sand-gravel mixed reservoirs with partial interlayer separation is established, simulating real sand-gravel mixed reservoirs. Furthermore, by designing the injection-end pressure acquisition system and the production-end, the fluid absorption and production of sandstone and conglomerate layers during chemical flooding can be clearly defined, thereby clarifying the crossflow patterns and influencing factors of injected fluids in sand-gravel mixed reservoirs. The physical simulation device and quantitative measurement method for interlayer crossflow in sand-gravel mixed reservoirs of this invention can provide an experimental basis for on-site design of fluid crossflow in sand-gravel mixed reservoirs and optimization of chemical flooding injection parameters, thereby adjusting interlayer crossflow phenomena and improving the sweep range of injected fluids.

[0006] To achieve the above technical objectives, the present invention adopts the following technical solution: A physical simulation device for interlayer flow in mixed sand and gravel layers includes a mixed sand and gravel core, wherein the mixed sand and gravel core is composed of sandstone core and conglomerate core stacked on top of each other, and the outer periphery of the mixed sand and gravel core is formed by epoxy resin casting. The sand and gravel mixed-layer core includes one injection end and two extraction ends; the injection end is shared by the sandstone layer and the conglomerate layer; the two extraction ends are respectively set for the sandstone layer core and the conglomerate layer core, namely the first extraction end and the second extraction end; both the injection end and the extraction end are provided with an impermeable physical barrier along the length direction at the interface of the sand and gravel mixed layer; The upper and lower walls of the sand and gravel mixed core are respectively equipped with a first pressure measuring point and a second pressure measuring point corresponding to the end of the physical barrier. These points are used to calculate the liquid absorption of the sand and gravel layers using Darcy's law based on the measured pressure values. The first and second extraction ends are respectively connected to a measuring cylinder for collecting and measuring the liquid extraction of the sand and gravel layers.

[0007] Furthermore, the sand-gravel mixed-layer core is a cuboid core, in which the sandstone core and the conglomerate core are of equal height.

[0008] Furthermore, the length of the sand-gravel mixed-layer core is 20-50cm, the width is 3.5-5.0cm, and the height is 3.5-5.0cm; the length of the physical partition at the injection end and the extraction end of the sand-gravel mixed-layer core is 4-7cm.

[0009] Furthermore, the injection end is provided with an injection end cap, and the two extraction ends are provided with extraction end caps.

[0010] Furthermore, there is one extraction end cap, and a partition plate is provided between the sandstone layer and the conglomerate layer corresponding to the extraction end cap.

[0011] Furthermore, it also includes a constant-speed pump, a valve, a piston container, a six-way valve, a gravel-mixed core, and a measuring cylinder connected in sequence; the gravel-mixed core is placed in a three-dimensional pressurization system, the injection end of the gravel-mixed core is connected to the six-way valve, and the extraction end is connected to the measuring cylinder; a pressure sensor is externally connected to the six-way valve.

[0012] Furthermore, the piston containers are two connected in parallel, and the two piston containers are sequentially filled with water and a binary composite system, the binary composite system comprising a polymer and a surfactant.

[0013] Furthermore, the polymer used has a viscosity range of 20-40 mPa·s, and the surfactant is a petroleum sulfonate.

[0014] Meanwhile, this invention provides a method for quantitatively measuring interlayer flow in gravel-sand mixed layers, employing any of the physical simulation devices for interlayer flow in gravel-sand mixed layers as described above. The method includes the following steps: Step S01: Design and manufacture core models, initially select the permeability range and mineral composition of the target section of gravel layer, design and manufacture mixed gravel cores, as well as cylindrical sandstone cores and cylindrical conglomerate cores with the same formula, and dry the cores after they are manufactured for later use. Step S02: Measure the effective permeability of the cylindrical sandstone core and cylindrical conglomerate core using the water permeability method. These represent the permeability of the sandstone layer and conglomerate layer in the mixed sandstone-conglomerate core, respectively. The sandstone layer is located above the conglomerate layer, and its permeability is [missing value]. The permeability of the conglomerate layer is ; Step S03: Vacuuming and water saturation are performed on the sand-gravel mixed-layer core, and then a binary composite system is injected at a constant rate. The injection end pressure of the sand-gravel mixed-layer core is recorded. 1. Stabilized pressure at the first pressure measurement point , second pressure measurement point stabilization pressure and the stable liquid production at the first extraction end Stable liquid production at the second extraction end , and These represent the fluid recovery conditions of the sandstone and conglomerate layers, respectively. The experiment was terminated after the pressure at both pressure measurement points was balanced and the fluid collection volume at both extraction ends was stable. Step S04: Utilizing the permeability of the sandstone layer , stabilize pressure and the permeability of the conglomerate layer , stabilize pressure The liquid absorption of the conglomerate and sandstone layers was calculated using Darcy's law, and the formulas used are as follows:

[0015] In the above formula (1): This refers to the volume of liquid absorbed, in ml. The effective permeability is expressed in mD; A is the core cross-sectional area, expressed in cm². 2 ; This refers to the injection end pressure; The stable pressure at the pressure measurement point is atm; μ is the viscosity of the injected fluid, mPa·s; L is the core length at the pressure measurement point, cm; i=1, 2, representing the sandstone layer and the conglomerate layer, respectively. Step S05: Comparative Analysis , and , The interlayer flow patterns in the gravel-sand mixed layers were clarified; the liquid absorption ratio and liquid production ratio were defined as the ratios of the flow rates at the injection and production ends of the two layers, respectively, i.e., the liquid absorption ratio. Product ratio By comparing the changes in the liquid absorption ratio and the liquid production ratio, the flow pattern of the injected fluid in the gravel-sand mixture was clarified. Step S06: Change the physical property parameters of the core model and the parameters of the injected fluid, and repeat steps S01-S05 to clarify the influence of different factors on the interlayer flow of the binary composite system; wherein, the physical property parameters of the core model include the permeability and pore throat structure of the gravel layer, and the parameters of the injected fluid include the injection rate and the viscosity of the injected binary composite system.

[0016] Further, in step S01, the mixed sand and gravel core is a cuboid core with a length of 20-50cm, a width of 3.5-5.0cm, and a height of 3.5-5.0cm; the cylindrical sandstone core and the cylindrical conglomerate core have a diameter of 2-3cm and a length of 5-10cm.

[0017] Compared with the prior art, the beneficial effects of the present invention are: (1) In order to clarify the interlayer flow law of sand and gravel mixed reservoir in Xinjiang oilfield, this invention provides a sand and gravel mixed core model that can be injected and produced separately. By combining the design of sand and gravel mixed type interlayer heterogeneous core model with theoretical calculation, the liquid absorption and production of sandstone and conglomerate layers in sand and gravel mixed core are quantitatively measured. The flow law and influencing factors of fluid in sand and gravel mixed layer are analyzed and clarified. It can provide an experimental basis for the field flow of fluid in sand and gravel mixed layer and the optimization design of chemical flooding injection parameters, so as to adjust the interlayer flow phenomenon and improve the sweep efficiency of injected fluid.

[0018] (2) Compared with existing patents (CN103498669A, CN107389396A), this application realizes the simulation of the combined injection and separate production development mode, which is closer to the actual mine, and focuses on the interlayer flow during the displacement process, rather than the final liquid production of each layer; and the study of the lithology-dominated flow law of sand and gravel mixed layers has not been involved in the prior art, while this application systematically simulates the interlayer flow law of sand and gravel mixed layers, and realizes the monitoring of the liquid absorption and liquid production of each layer in the combined injection and separate production process by combining theoretical calculations, and clarifies the interlayer flow law by the changes in the liquid absorption and liquid production of each layer; at the same time, a series of displacement experiments can be carried out by changing the core physical property parameters and the injected fluid parameters, which is conducive to evaluating the interlayer heterogeneous flow law caused by different lithologies; (3) The present invention directly measures and calculates the liquid absorption and production of each rock layer without the need for oil displacement experiments. It can be achieved simply by injecting a binary composite system. The testing method is simple, efficient and accurate. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the overall structure of the physical simulation device for interlayer crossflow in a sand-gravel mixed layer according to an embodiment of the present invention. Figure 2 This is a schematic diagram of the structure of a sand-gravel mixed-layer rock core according to an embodiment of the present invention; Figure 3 The figures show the water permeability and pressure variation curves of cylindrical sandstone cores and cylindrical conglomerate cores according to embodiments of the present invention. Figure 4 This is a bar chart showing the liquid absorption ratio and liquid production ratio of different binary composite systems at different viscosities according to embodiments of the present invention; Figure 5This is a bar chart showing the liquid absorption ratio and liquid production ratio of different binary composite systems at different injection rates according to embodiments of the present invention. Explanation of markings in the diagram: 1-Constant speed pump; 2-Piston container; 3-Pressure sensor; 4-Six-way valve; 5-Sand and gravel mixed-layer core; 6-Measuring cylinder; 7-Three-dimensional pressurization system; 501-Injection end cap; 502-Injection end; 503-Physical partition; 504-First pressure measuring point; 505-Second pressure measuring point; 506-Epoxy resin adhesive layer; 507-First extraction end; 508-Second extraction end; 509-Extraction end cap; 510-Separator plate. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] Example 1 This invention provides a physical simulation device for interlayer flow in sand and gravel mixed layers, such as... Figure 1 As shown, the physical simulation device includes a constant-speed pump 1, a piston container 2, a six-way valve 4, a gravel-bearing mixed core 5, and a measuring cylinder 6 connected in sequence. The gravel-bearing mixed core 5 is placed in a three-dimensional pressurization system 7. The injection end of the gravel-bearing mixed core 5 is connected to the six-way valve 4, and the extraction end is connected to the measuring cylinder 6. A pressure sensor 3 is externally connected to the six-way valve 4. The pressure sensor 3 is used to record the injection end pressure of the gravel-bearing mixed core during the displacement process. .

[0022] The piston containers 2 are two connected in parallel, each containing water and a binary composite system sequentially. The binary composite system comprises a polymer and a surfactant. The polymer has a viscosity of 35 mPa·s, and the surfactant is a petroleum sulfonate. The piston container containing water is used to inject water into the sand-gravel mixed-layer core during the initial stage of the experiment to test the effective permeability of the cylindrical sandstone and conglomerate cores using a water permeability measurement method. The piston container containing the binary composite system is used to inject the binary composite system into the sand-gravel mixed-layer core during the experiment to test the pressure at different layers and simulate and analyze the interlayer flow characteristics of the binary composite system.

[0023] like Figure 2As shown, the mixed sand and gravel core 5 is composed of sandstone core and conglomerate core stacked one on top of the other. The mixed sand and gravel core 5 is a cuboid core with dimensions of 4.5cm in width, 4.5cm in height, and 30cm in length. The sandstone core and the conglomerate core in the mixed sand and gravel core 5 have the same height, both being 2.25cm. The outer periphery of the mixed sand and gravel core 5 is formed by epoxy resin casting.

[0024] The mixed sand and gravel core 5 includes an injection end 502 and two extraction ends; the injection end 502 is provided with an injection end cap 501; the two extraction ends are a first extraction end 507 and a second extraction end 508, the first extraction end 507 corresponds to the sandstone core and the second extraction end 508 corresponds to the conglomerate core; the two extraction ends are provided with an extraction end cap 509, the extraction end cap 509 corresponds to a partition plate 510 between the sandstone and conglomerate layers; the injection end cap 501 and the extraction end cap 509 are used to seal the two ends of the mixed sand and gravel core when the experimental device is placed, so as to facilitate storage and placement.

[0025] Both the injection end 502 and the extraction end are provided with an impermeable physical barrier along the length direction at the junction of the sand and gravel mixed layer. The length of the physical barrier is 5 cm. On the upper and lower walls of the sand and gravel mixed core 5, corresponding to the ends of the physical barrier 503, a first pressure measuring point 504 and a second pressure measuring point 505 are respectively provided to calculate the liquid absorption of the sand and gravel layers using Darcy's law based on the measured pressure values. At the same time, the first extraction end 507 and the second extraction end 508 of the sand and gravel mixed core 5 are respectively connected to a measuring cylinder 6 to collect and measure the liquid extraction of the sand and gravel layers.

[0026] Example 2 A quantitative measurement method for interlayer channeling in gravel-sand mixed layers is proposed. This method employs a physical simulation device for interlayer channeling in gravel-sand mixed layers as described in Example 1. The device simulates the changes in the liquid uptake and production profiles during the injection process of a binary composite system, clarifying the influence of reservoir properties and injection parameters on interlayer channeling. The experimental procedure is as follows: design and fabrication of a core model – implementation of displacement experiments – pressure data analysis – determination of channeling patterns.

[0027] The method specifically includes the following steps: Step S01: Design and fabricate core models, initially select the permeability range and mineral composition of the target gravel layer, design and fabricate mixed gravel cores, as well as cylindrical sandstone cores and cylindrical conglomerate cores with the same formula, and dry the cores for later use; wherein, the mixed gravel core is a cuboid core with dimensions of 4.5cm width × 4.5cm height × 30cm length, the upper part is the sandstone core with a height of 2.25cm, and the lower part is the conglomerate core with a height of 2.25cm; the cylindrical sandstone core and the cylindrical conglomerate core have a diameter of 2.5cm and a length of 5cm.

[0028] Step S02: Measure the effective permeability of the cylindrical sandstone core and cylindrical conglomerate core using the water permeability method. These represent the permeability of the sandstone layer and conglomerate layer in the mixed sandstone-conglomerate core, respectively. The sandstone layer is located above the conglomerate layer, and its permeability is [missing value]. The permeability of the conglomerate layer is ; Step S03: Vacuuming and water saturation are performed on the sand-gravel mixed-layer core, and then a binary composite system is injected at a constant rate. The injection end pressure of the sand-gravel mixed-layer core is recorded. 1. Stabilized pressure at the first pressure measurement point , second pressure measurement point stabilization pressure and the stable liquid production of the first extraction end 507 Stable liquid production at the second extraction end 508 , and The two pressure measurement points represent the fluid production conditions of the sandstone and conglomerate layers, respectively. The experiment was terminated after the pressure at both pressure measurement points was balanced and the fluid production at both production ends was stable. Step S04: Utilizing the permeability of the sandstone layer , stabilize pressure and the permeability of the conglomerate layer , stabilize pressure The liquid absorption of the conglomerate and sandstone layers was calculated using Darcy's law, and the formulas used are as follows: (1) In the above formula (1): This refers to the volume of liquid absorbed, in ml. The effective permeability is expressed in mD; A is the core cross-sectional area, expressed in cm². 2 ; This refers to the injection end pressure; The stable pressure at the pressure measurement point is atm; μ is the viscosity of the injected fluid, mPa·s; L is the core length at the pressure measurement point, cm; i=1, 2, representing the sandstone layer and the conglomerate layer, respectively. Step S05: Comparative Analysis , and , The interlayer flow patterns in the gravel-sand mixed layers were clarified; the liquid absorption ratio and liquid production ratio were defined as the ratios of the flow rates at the injection and production ends of the two layers, respectively, i.e., the liquid absorption ratio. Product ratio By comparing the changes in the liquid absorption ratio and the liquid production ratio, the flow pattern of the injected fluid in the gravel-sand mixture was clarified. Step S06: Change the physical property parameters of the core model and the parameters of the injected fluid, and repeat steps S01-S05 to clarify the influence of different factors on the interlayer flow of the binary composite system; wherein, the physical property parameters of the core model include the permeability and pore throat structure of the gravel layer, and the parameters of the injected fluid include the injection rate and the viscosity of the injected binary composite system.

[0029] Example 3 The interlayer flow physics simulation device for sand-gravel mixed layers in Example 1 and the quantitative measurement method for interlayer flow quantification of sand-gravel mixed layers in Example 2 were used to characterize and analyze the flow variability during the chemical flooding development process of the target sand-gravel mixed layer in the Qixi area of ​​Xinjiang. Specifically, the gas permeability of the sandstone layer was selected as 300 mD, and the gas permeability of the conglomerate layer was selected as 50 mD; the polymer viscosity used in the binary composite system was 30 mPa·s, and the surfactant was petroleum sulfonate; the core model dimensions of the sand-gravel mixed layer were 3.8 cm wide × 3.8 cm high × 30 cm long. The sand-gravel mixed layer core was designed and fabricated according to the on-site mineral composition formula, and experiments were conducted sequentially according to the steps described in Example 2. The experimental scheme is shown in Table 1.

[0030] Table 1 Experimental Protocol

[0031] (1) Permeability test of sandstone and conglomerate layers Water permeability tests were conducted using cylindrical sandstone cores (2.5 cm in diameter and 5 cm in length) and cylindrical conglomerate cores, and the injection pressure curves were obtained as follows: Figure 3 As shown, the final stable injection-production pressure differentials for the two layers were 0.021 MPa and 0.104 MPa, respectively. Using Darcy's law, the permeabilities of the sandstone and conglomerate layers were calculated to be 161.64 mD and 32.64 mD, respectively. The formulas used are as follows: K=100 QμL / AΔP(2) In equation (2) above, K is the core permeability (mD); Q is the injection rate (mL / s); μ is the viscosity of the injected fluid (cP); L is the core length (cm); and A is the core cross-sectional area (cm²). 2 ΔP - injection-production pressure difference, atm.

[0032] (2) Interlayer flow pattern of gravel mixed layers According to the experimental scheme in Table 1, the first group of experiments was carried out according to the steps described in Example 2. The stable pressure of the first pressure measuring point 504 and the second pressure measuring point 505, the stable liquid production of the first extraction end 507 and the second extraction end 508 were obtained, and the liquid absorption ratio I and the liquid production ratio O were calculated and summarized as shown in Table 2.

[0033] Table 2. Results of relevant parameters for interlayer flow in the gravel-sand mixed layer.

[0034] Table 2 shows that the liquid uptake ratio at the injection end of the gravel-sand mixed layer is 4.63, while the liquid production ratio at the production end is 9.00, indicating that interlayer flow from the conglomerate layer to the sandstone layer occurs within the gravel-sand mixed layer. This phenomenon suggests that although the conglomerate layer has low permeability, due to its large pore throats, fluid enters the conglomerate layer at the injection end, but gradually flows into the more permeable sandstone layer during migration, resulting in a higher final liquid production ratio.

[0035] (3) Study on the influencing factors of interlayer flow in gravel mixed layers According to the experimental scheme in Table 1, the second to eighth groups of experiments were carried out in accordance with the implementation steps of this application. The stable pressure of the first pressure measuring point 504 and the second pressure measuring point 505, the stable liquid production of the first extraction end 507 and the second extraction end 508 were obtained, and the liquid absorption ratio I and the liquid production ratio O were calculated and summarized as shown in Table 3.

[0036] Table 3. Results of relevant parameters for interlayer flow in the gravel-sand mixed layer.

[0037] Table 3 shows that the results of the experiments in groups 1-4 are as follows: Figure 4 As shown, as the viscosity of the binary composite system increased from 15 to 64 mPa·s, the liquid uptake ratio of the gravel layer decreased monotonically from 5.57 to 3.64, indicating that increasing the viscosity led to an increase in injection pressure, which significantly increased the liquid uptake of the conglomerate layer. At the same time, the liquid production ratio first increased from 7.33 to 9.00 and then decreased to 6.14, indicating that increasing the viscosity of the binary composite system first increased the flow rate of fluid from the conglomerate layer to the sandstone layer and then decreased.

[0038] Comparing experiments 3 and 5-8 as follows Figure 5 As shown, when the injection rate increased from 0.3 mL / min to 2 mL / min, the liquid uptake ratio of the gravel layer fluctuated between 3.28 and 4.56, indicating that the change in injection rate had little effect on the liquid uptake of the gravel-gravel mixed layer. The liquid production ratio first increased and then decreased with the increase of injection rate and then tended to be stable, indicating that the flow rate from the conglomerate layer to the sandstone layer first decreased and then increased with increasing injection rate and then tended to be stable when the injection rate reached 0.8 mL / min. Through Table 2, Table 3 and Figure 4 , Figure 5 Analysis reveals that during the injection of mixed sand and gravel layers, interlayer flow occurs due to the poor physical properties of the conglomerate reservoir. Both the injection rate and the viscosity of the binary composite system affect the liquid uptake ratio and the flow situation. Moreover, the viscosity of the binary composite system has a significantly greater impact on the injection-production ratio than the injection rate.

[0039] The above analysis shows that the sandstone layer is the main layer for fluid absorption and diffusion in the sand-gravel mixed layer. A moderate binary system viscosity and injection rate are more conducive to the diffusion of the sandstone layer. From the perspective of utilizing the conglomerate reservoir, the injection viscosity of the binary system should be increased to increase the injection pressure and thus increase the diffusion of the conglomerate reservoir.

[0040] The above description is merely an embodiment of this application and is not intended to limit the invention. Any modifications, equivalent substitutions, and improvements made within the scope of this application should be included within the protection scope of this invention.

Claims

1. A physical simulation device for interlayer flow in a mixed sand and gravel layer, characterized in that, The core includes a mixed sand and gravel core, which is composed of sandstone core and conglomerate core stacked on top of each other, and the outer periphery of the mixed sand and gravel core is formed by epoxy resin casting. The sand and gravel mixed-layer core includes one injection end and two extraction ends; the injection end is shared by the sandstone layer and the conglomerate layer; the two extraction ends are respectively set for the sandstone layer core and the conglomerate layer core, namely the first extraction end and the second extraction end; both the injection end and the extraction end are provided with an impermeable physical barrier along the length direction at the interface of the sand and gravel mixed layer; The upper and lower walls of the sand and gravel mixed core are respectively equipped with a first pressure measuring point and a second pressure measuring point at the end of the physical barrier corresponding to the injection end. These points are used to calculate the liquid absorption of the sand and gravel layers using Darcy's law based on the measured pressure values. The first and second extraction ends are respectively connected to a measuring cylinder for collecting and measuring the liquid extraction of the sand and gravel layers. The length of the mixed sand and gravel core is 20-50cm, the width is 3.5-5.0cm, and the height is 3.5-5.0cm; the length of the physical partition at the injection end and the extraction end of the mixed sand and gravel core is 4-7cm.

2. The physical simulation device for interlayer flow in a mixed sand and gravel layer according to claim 1, characterized in that, The mixed sand and gravel core is a cuboid core, in which the sandstone core and the conglomerate core are of equal height.

3. The physical simulation device for interlayer flow in a mixed sand and gravel layer according to claim 1, characterized in that, The injection end is provided with an injection end cap, and the two extraction ends are provided with extraction end caps.

4. The physical simulation device for interlayer flow in a mixed sand and gravel layer according to claim 3, characterized in that, There is one extraction end cap, and a partition plate is provided between the sandstone layer and the conglomerate layer corresponding to the extraction end cap.

5. The physical simulation device for interlayer flow in a mixed sand and gravel layer according to claim 1, characterized in that, It also includes a constant speed pump, a valve, a piston container, a six-way valve, a gravel-mixed core, and a measuring cylinder connected in sequence; the gravel-mixed core is placed in a three-dimensional pressurization system, the injection end of the gravel-mixed core is connected to the six-way valve, and the extraction end is connected to the measuring cylinder; a pressure sensor is externally connected to the six-way valve.

6. The physical simulation device for interlayer flow in a mixed sand and gravel layer according to claim 5, characterized in that, The piston containers are two connected in parallel, and each piston container is sequentially filled with water and a binary composite system, which includes a polymer and a surfactant.

7. The physical simulation device for interlayer flow in a mixed sand and gravel layer according to claim 6, characterized in that, The polymer used has a viscosity range of 20-40 mPa·s, and the surfactant is a petroleum sulfonate.

8. A method for quantitatively measuring interlayer flow in a gravel-sand mixed layer, employing a physical simulation device for interlayer flow in a gravel-sand mixed layer as described in any one of claims 1-6, characterized in that, The method includes the following steps: Step S01: Design and manufacture core models, initially select the permeability range and mineral composition of the target section of gravel layer, design and manufacture mixed gravel cores, as well as cylindrical sandstone cores and cylindrical conglomerate cores with the same formula, and dry the cores after they are manufactured for later use. Step S02: Measure the effective permeability of the cylindrical sandstone core and cylindrical conglomerate core using the water permeability method. These represent the permeability of the sandstone layer and conglomerate layer in the mixed sandstone-conglomerate core, respectively. The permeability of the sandstone layer is [value missing]. The permeability of the conglomerate layer is ; Step S03: Vacuuming and water saturation are performed on the sand-gravel mixed-layer core, and then a binary composite system is injected at a constant rate. The injection end pressure of the sand-gravel mixed-layer core is recorded.

1. Stabilized pressure at the first pressure measurement point , second pressure measurement point stabilization pressure and the stable liquid production at the first extraction end Stable liquid production at the second extraction end , and The two pressure measurement points represent the fluid production conditions of the sandstone and conglomerate layers, respectively. The experiment was terminated after the pressure at both pressure measurement points was balanced and the fluid production at both production ends was stable. Step S04: Utilize the permeability of the sandstone layer , stabilize pressure and the permeability of the conglomerate layer , stabilize pressure The liquid absorption of the conglomerate and sandstone layers was calculated using Darcy's law, and the formulas used are as follows: In the above formula (1): This refers to the volume of liquid absorbed, in ml. The effective permeability is expressed in mD; A is the core cross-sectional area, expressed in cm². 2 ; This refers to the injection end pressure; The stable pressure at the pressure measurement point is atm; μ is the viscosity of the injected fluid, mPa·s; L is the core length at the pressure measurement point, cm; i=1, 2, representing the sandstone layer and the conglomerate layer, respectively; Step S05: Comparative Analysis , and , The interlayer flow patterns in the gravel-sand mixed layers were clarified; the liquid absorption ratio and liquid production ratio were defined as the ratios of the flow rates at the injection and production ends of the two layers, respectively, i.e., the liquid absorption ratio. Product ratio By comparing the changes in the liquid absorption ratio and the liquid production ratio, the flow pattern of the injected fluid in the gravel-sand mixture was clarified. Step S06: Change the physical property parameters of the core model and the parameters of the injected fluid, and repeat steps S01-S05 to clarify the influence of different factors on the interlayer flow of the binary composite system; wherein, the physical property parameters of the core model include the permeability and pore throat structure of the gravel layer, and the parameters of the injected fluid include the injection rate and the viscosity of the injected binary composite system.

9. A method for quantitatively measuring interlayer flow in a gravel-sand mixed layer according to claim 8, characterized in that, In step S01, the mixed sand and gravel core is a cuboid core with a length of 20-50cm, a width of 3.5-5.0cm, and a height of 3.5-5.0cm; the cylindrical sandstone core and the cylindrical conglomerate core have a diameter of 2-3cm and a length of 5-10cm.

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