Multi-layer heavy oil reservoir thermal recovery experiment device, system and method

Abstract

The multi-layer heavy oil reservoir thermal recovery experimental device comprises an oil reservoir model, a closed bin body and a heater, the oil reservoir model comprises a first simulation wellbore and a second simulation wellbore, and at least one oil layer is communicated between the first simulation wellbore and the second simulation wellbore; each oil layer is provided with at least one pressure measuring point hole and a plurality of temperature measuring point holes arranged at intervals, a pressure detection piece is installed in each pressure measuring point hole, and a temperature detection piece is installed in each temperature measuring point hole; the closed bin body is provided with a confining pressure fluid channel, a first shaft channel and a second shaft channel, the first shaft channel and the second shaft channel are communicated with the first simulation shaft and the second simulation shaft respectively, a containing cavity is formed in the closed bin body, and an oil reservoir model is arranged in the containing cavity; the heater is arranged in the containing cavity and used for enabling the interior of the closed bin body to be in an oil reservoir formation temperature state; and the like. The invention further discloses a multi-layer heavy oil reservoir thermal recovery experiment system and an experiment method for achieving multi-layer heavy oil reservoir thermal recovery by applying the experiment system.

Description

Technical Field

[0001] The invention relates to the technical field of oil and gas field development engineering, and in particular to a thermal recovery experimental device, system and method for a multi-layer heavy oil reservoir. Background Art

[0002] Heavy oil viscosity reduction development technologies mainly include steam injection viscosity reduction, underground combustion heat generation and thermal composite development. Among them, steam injection viscosity reduction development technology mainly heats the oil layer by the heat carried by steam. The specific methods of heavy oil production mainly include steam stimulation, steam drive and steam-assisted gravity drainage (SAGD) technology. During the steam stimulation process, after the formation crude oil contacts the steam, the area where the viscosity is reduced by heat is mainly concentrated in the near-well area. In addition, this method can also provide suitable pressure conditions for steam drive. Steam drive is the main replacement method after steam stimulation. The mechanism of steam drive is mainly to reduce the viscosity of heavy oil and increase the mobility of crude oil. The steam phase is composed of water vapor and hydrocarbon vapor, which condense, dilute and displace the front crude oil together.

[0003] Multilayer heavy oil reservoirs are one of the main types of heavy oil reservoirs, and multilayer combined production is often used for development. For heavy oil reservoirs in the initial state, due to the interlayer heterogeneity of the reservoir and the difference in fluid properties in the vertical direction, interlayer interference occurs between small layers. With the continuous development of the oil field, the difference in formation pressure, water content and steam overburden between small layers make the interlayer interference more prominent, which ultimately makes it difficult to displace each layer evenly, thereby affecting the final recovery rate.

[0004] However, how to simulate the above process more accurately under high temperature and high pressure conditions, and to be able to observe the fluid migration and distribution laws at a macroscopic level, to ensure that the thermal recovery of multi-layer heavy oil reservoirs under indoor conditions is more similar to that of oil fields, and thus to better provide a basis for numerical simulation and field development, is still difficult to solve. Summary of the invention

[0005] The purpose of the present invention is to provide a multi-layer heavy oil reservoir thermal recovery experimental device, system and method to truly restore the actual geological conditions of the multi-layer heavy oil reservoir, so as to more accurately simulate and observe the thermal recovery process of the heavy oil reservoir.

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

[0007] The present invention provides a multi-layer heavy oil reservoir thermal recovery experimental device, comprising: a reservoir model, comprising a first simulated wellbore and a second simulated wellbore, at least one oil layer is connected between the first simulated wellbore and the second simulated wellbore, each of the oil layers is provided with at least one pressure measuring point hole and a plurality of temperature measuring point holes arranged at intervals, a pressure detecting element is installed in the pressure measuring point hole, and a temperature detecting element is installed in each of the temperature measuring point holes; a closed warehouse body, on which a confining pressure fluid channel, a first wellbore channel connected to the first simulated wellbore, and a second wellbore channel connected to the second simulated wellbore are provided, a containing cavity is formed in the closed warehouse body, and the reservoir model is arranged in the containing cavity; a heater is arranged in the containing cavity, and the heater is used to make the inside of the closed warehouse body in a reservoir formation temperature state; the multi-layer heavy oil reservoir thermal recovery experimental device has a first working state and a second working state, in the first working state, the first simulated wellbore and the second simulated wellbore are simultaneously in an injection state or a production state; in the second working state, the first simulated wellbore and the second simulated wellbore are respectively in an injection state and a production state.

[0008] Preferably, a visual window is provided on the side wall of the closed chamber close to the reservoir model. Under experimental conditions, the accommodating cavity is filled with a transparent confining pressure fluid medium, so that the visual window can be used to observe the migration and distribution of the fluid in each of the oil layers.

[0009] Preferably, the closed storage body is a cylindrical cavity, the axis of the closed storage body is perpendicular to the axis of the first simulated wellbore and the second simulated wellbore, there are multiple oil layers, and the multiple oil layers are arranged at intervals along the axis direction of the first simulated wellbore or the second simulated wellbore, and the closed storage body is provided with multiple visible windows corresponding to the multiple oil layers in a one-to-one manner along the circumferential direction.

[0010] Preferably, there are three oil layers, and correspondingly, there are three visual windows, two adjacent visual windows are staggered at 50° along the circumferential direction of the closed warehouse body, and the visual radius of the visual windows is 30 mm.

[0011] Preferably, the reservoir model is fixedly connected to the closed chamber body via a model bracket, the heater is arranged on a side of the reservoir model away from the visual window, and a temperature probe for detecting the temperature in the chamber is also arranged between the heater and the reservoir model.

[0012] Preferably, the closed bin body includes an axially extending shell and end sealing plates arranged at both ends of the shell, and a circumferentially closed slide rail structure is arranged on the end sealing plate. The slide rail structure divides the end sealing plate into a movable inner plate and a fixed outer plate. The shell is connected to the movable inner plate, and the accommodating cavity is formed between the movable inner plate and the shell. The movable inner plate can rotate circumferentially and be locked along the slide rail structure.

[0013] Preferably, a multi-core connector is provided on the closed storage body, and the multi-core connector is electrically connected to a plurality of temperature detection components in each of the oil layers.

[0014] Another object of the present invention is a multi-layer heavy oil reservoir thermal recovery experimental system, comprising: the multi-layer heavy oil reservoir thermal recovery experimental device as described above; a confining pressure fluid injection pipeline, connected between the confining pressure fluid reservoir and the confining pressure fluid channel, and a confining pressure pump is provided on the confining pressure fluid injection pipeline; a first steam injection pipeline, connected between the first deionized water reservoir and the first wellbore channel, and in the direction from the first deionized water reservoir to the first wellbore channel, a first steam pump, a first steam generator, and a first vent valve are sequentially provided on the first steam injection pipeline; a second steam injection pipeline, connected between the second deionized water reservoir and the first wellbore channel; The second steam injection pipeline is provided with a second steam pump, a second steam generator, and a second vent valve in sequence between the second wellbore channel and the second wellbore channel, from the second deionized water reservoir to the first wellbore channel; the crude oil injection pipeline is provided with an intermediate container for storing crude oil, one end of the crude oil injection pipeline is connected to the first steam injection pipeline between the first steam pump and the first steam generator, and the other end of the crude oil injection pipeline is connected to the first steam injection pipeline between the first vent valve and the first wellbore channel; deionized water is introduced into the crude oil injection pipeline from the first steam injection pipeline In this state, the intermediate container can feed crude oil into the reservoir model; a first production pipeline, on which a first back-pressure valve is arranged, one end of the first production pipeline is connected to the first steam injection pipeline between the first vent valve and the first wellbore channel, and the other end of the first production pipeline is connected to a first meter; a second production pipeline, on which a second back-pressure valve is arranged, one end of the second production pipeline is connected to the second steam injection pipeline between the second vent valve and the second wellbore channel, and the other end of the second production pipeline is connected to a second meter; a back-pressure valve pressure control pipeline, on which a back-pressure pump is arranged, the One end of the back-pressure valve pressure control pipeline is connected to the third deionized water reservoir, and the other end of the back-pressure valve pressure control pipeline is connected to the first back-pressure valve and the second back-pressure valve; the crude oil injection pipeline and the first production pipeline are connected to the first steam injection pipeline between the first vent valve and the first wellbore channel through a first six-way valve; the second production pipeline is connected to the second steam injection pipeline between the second vent valve and the second wellbore channel through a second six-way valve; the crude oil injection pipeline is connected to the first steam injection pipeline between the first steam pump and the first steam generator through a three-way valve.

[0015] The present invention also provides an experimental method for realizing thermal recovery of multi-layer heavy oil reservoirs by using the above-mentioned multi-layer heavy oil reservoir thermal recovery experimental system, comprising:

[0016] Step S00, start the confining pressure pump, and pass the confining pressure fluid in the confining pressure fluid reservoir into the closed chamber to form a pressure chamber; turn on the heater to make the interior of the closed chamber at the reservoir formation temperature.

[0017] Step S10, start the back pressure pump, and inject the deionized water in the third deionized water reservoir into the back pressure valve pressure control pipeline until the pressure of the first back pressure valve and the second back pressure valve reaches the formation pressure required for the first round of steam stimulation experiment.

[0018] Step S20, adjusting the first six-way valve and the three-way valve to connect the first steam pump to the first wellbore channel through the crude oil injection pipeline; adjusting the second six-way valve to connect the second production pipeline to the second wellbore channel; starting the first steam pump to pass the crude oil in the intermediate container into the reservoir model, and continuously pressurizing the closed warehouse body through the confining pressure pump, and when crude oil appears in the second metering device, closing the first steam pump and the back pressure pump.

[0019] Step S30, adjusting the three-way valve, connecting the first steam pump and the first steam generator, setting the steam temperature of the first steam generator to the steam saturation temperature under the formation pressure corresponding to step S10, turning on the first steam pump and the first steam generator, and using the first steam generator to inject the first steam into the steam pipeline to hold the steam pressure to the formation pressure required for the first round of steam injection experiment; setting the steam temperature of the second steam generator to the steam saturation temperature under the formation pressure corresponding to step S10, turning on the second steam pump and the second steam generator, and using the second steam generator to inject the first steam into the steam pipeline to hold the steam pressure to the formation pressure required for the first round of steam injection experiment; setting the steam temperature of the second steam generator to the steam saturation temperature under the formation pressure corresponding to step S10, turning on the second steam pump and the second steam generator, and using the second steam generator to inject the first steam into the steam pipeline to hold the steam pressure to the formation pressure required for the first round of steam injection experiment The steam in the second steam injection pipeline is pressurized to the formation pressure required for the first round of steam intake and discharge experiment; the first six-way valve is adjusted to connect the first steam injection pipeline with the first wellbore channel, and the second six-way valve is adjusted to connect the second steam injection pipeline with the second wellbore channel, so as to simultaneously introduce steam into the first wellbore channel and the second wellbore channel, and the closed chamber is continuously pressurized by the confining pressure pump; when the steam injection time reaches the experimental steam injection time requirement, the first steam pump, the first steam generator, the second steam pump, the second steam generator and all valves are closed to shut down the well.

[0020] Step S40, after the soaking time requirement is reached, start the back-pressure pump, and inject the deionized water in the third deionized water reservoir into the back-pressure valve pressure control pipeline, until the pressure of the first back-pressure valve and the second back-pressure valve reaches the formation pressure required for the first round of steam intake and exhaust experiments; adjust the first six-way valve to connect the first production pipeline with the first wellbore channel, and adjust the second six-way valve to connect the second production pipeline with the second wellbore channel, so that the fluid in the reservoir model flows into the first meter and the second meter at the same time; when the fluid in the first meter and the second meter no longer increases, close all valves and the back-pressure pump, and the first round of steam intake and exhaust experiments is completed.

[0021] Step S50, repeating steps S10, S30, and S40 for multiple times to perform multiple rounds of steam stimulation experiments, wherein the pressures of the first back pressure valve and the second back pressure valve are correspondingly set to the formation pressures required for each round of steam stimulation experiments.

[0022] Step S60, start the back pressure pump to inject the deionized water in the third deionized water reservoir into the back pressure valve pressure control pipeline until the pressure of the second back pressure valve reaches the formation pressure required for the steam flooding experiment.

[0023] Step S70, adjust the three-way valve to connect the first steam pump and the first steam generator, set the steam temperature of the first steam generator to the temperature required for the steam drive experiment, start the first steam pump and the first steam generator, and use the first steam generator to inject the first steam into the steam in the pipeline to hold the pressure to the formation pressure required for the steam drive experiment.

[0024] Step S80, adjusting the first six-way valve to connect the first steam injection pipeline with the first wellbore channel, and introducing steam into the first wellbore channel; adjusting the second six-way valve to connect the second production pipeline with the second wellbore channel, and allowing the fluid in the reservoir model to flow into the second meter.

[0025] Step S90, when the temperature of each oil layer near the second simulated wellbore approaches the steam temperature and the crude oil accounts for no more than 2% of the fluid flowing into the second metering device, the first steam generator is closed, the first vent valve is opened, and after the deionized water in the first deionized water reservoir reduces the temperature of the steam generator to room temperature, the first steam pump is closed, the back pressure pump is closed, the pressure of the second back pressure valve is at atmospheric pressure, and after the closed chamber is depressurized through the second back pressure valve, the heater is closed.

[0026] Preferably, the difference between the internal pressure of the closed storage body and the crude oil flow pressure and steam flow pressure entering the reservoir model is no more than 1 MPa.

[0027] The characteristics and advantages of the present invention are:

[0028] 1. The multi-layer heavy oil reservoir thermal recovery experimental device provided in the present application is provided with a closed chamber body to facilitate the maintenance of the reservoir formation simulation in the chamber during the experiment, thereby ensuring the accuracy of the experimental results; different working states can be entered by changing the injection and production states of the first simulated wellbore and the second simulated wellbore, so that a variety of experiments can be completed through one experimental device, which is flexible and widely applicable; at least one pressure measuring point hole and a plurality of temperature measuring point holes arranged at intervals are provided on each oil layer to facilitate the installation of the detection component, thereby facilitating the parameter acquisition and state monitoring during the experiment.

[0029] 2. The multi-layer heavy oil reservoir thermal recovery experimental system provided in the present application can truly restore the actual geological conditions of the multi-layer heavy oil reservoir, not only can it simulate the thermal recovery development process of the multi-layer heavy oil reservoir, but also can study the development dynamics and production laws of the single-layer heavy oil reservoir under different conditions, and can even simulate the development of the multi-layer heavy oil reservoir under multiple conditions, including multi-component thermal fluid drive, chemical composite drive, steam foam drive and non-condensate gas auxiliary, etc., which can make up for the shortcomings of the existing experimental devices that only consider single-layer reservoirs or use multi-tubes to simulate multi-layer reservoirs. The experimental system can effectively carry out indoor simulations of different development methods of multi-layer heavy oil reservoirs, and can study the influence of static geological parameters (including the number of interlayers, oil layer thickness distribution, permeability, porosity, etc.) and dynamic injection parameters (including steam dryness, production-injection ratio, periodic injection volume, etc.) of the reservoir on the mining effect under different development methods. At the same time, the temperature evolution law and the remaining oil distribution in the production process can also be studied.

[0030] 3. The experimental method for thermal recovery of multi-layer heavy oil reservoirs provided in this application is based on a similar design, and a similar design is also carried out on the permeability taking into account motion constraints. Therefore, this experimental method can more realistically and effectively simulate the thermal development dynamics and production laws of multi-layer heavy oil reservoirs, and provide strong support for the reservoir engineering analysis of actual thermal development of multi-layer heavy oil reservoirs. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0032] Figure 1 It is a structural schematic diagram of a multi-layer heavy oil reservoir thermal recovery experimental device provided in an embodiment of the present invention;

[0033] Figure 2A schematic diagram of the structure of the reservoir model provided in an embodiment of the present invention;

[0034] Figure 3 A schematic diagram of the distribution of temperature measuring point holes and pressure measuring point holes in each oil layer in the reservoir model provided in an embodiment of the present invention;

[0035] Figure 4 It is a schematic diagram of the state of the multi-layer heavy oil reservoir thermal recovery experimental device provided in an embodiment of the present invention in the experimental preparation stage;

[0036] Figure 5 It is a schematic diagram of the state of the multi-layer heavy oil reservoir thermal recovery experimental device provided in an embodiment of the present invention when entering the experimental stage;

[0037] Figure 6 A schematic diagram of the composition of a multi-layer heavy oil reservoir thermal recovery experimental system provided in an embodiment of the present invention;

[0038] Figure 7 A heating cavity development diagram obtained by the thermal recovery experimental system for a multi-layer heavy oil reservoir provided in an embodiment of the present invention under a thermal recovery experimental method for a multi-layer heavy oil reservoir after three rounds of steam stimulation;

[0039] Figure 8 A heating cavity development diagram obtained by the multi-layer heavy oil reservoir thermal recovery experimental system provided in an embodiment of the present invention under a multi-layer heavy oil reservoir thermal recovery experimental method after six rounds of steam stimulation;

[0040] Fig. 9 A heating chamber / steam chamber development diagram for 270 minutes of steam flooding obtained by the multi-layer heavy oil reservoir thermal recovery experimental system provided in an embodiment of the present invention under a multi-layer heavy oil reservoir thermal recovery experimental method;

[0041] Fig.10 It is a heating chamber / steam chamber development diagram of steam flooding 310 minutes obtained by the multi-layer heavy oil reservoir thermal recovery experimental system provided in the embodiment of the present invention under the multi-layer heavy oil reservoir thermal recovery experimental method.

[0042] Description of Figure Numbers:

[0043] 1. Thermal recovery experimental device for multi-layer heavy oil reservoir; 110. Reservoir model; 111. First simulated wellbore; 112. Second simulated wellbore; 113. Oil layer; 114. Pressure measuring point hole; 115. Temperature measuring point hole; 116. Aluminum block shell; 117. Perforation hole; 120. Closed chamber; 121. Confining pressure fluid channel; 122. First wellbore channel; 123. Second wellbore channel; 124. Pressure measuring channel; 125. Visual window; 126. Confining pressure fluid fast channel; 127. End sealing plate; 128. Slide rail structure; 129. Insulation cover; 130. Heater; 140. Model bracket; 150. Temperature probe; 160. Multi-core connector;

[0044] 2. Confining pressure fluid injection pipeline; 3. Confining pressure fluid reservoir; 4. Confining pressure pump; 5. First steam injection pipeline; 6. First deionized water reservoir; 7. First steam pump; 8. First steam generator; 9. First vent valve; 10. Second steam injection pipeline; 11. Second deionized water reservoir; 12. Second steam pump; 13. Second steam generator; 14. Second vent valve; 15. Crude oil injection pipeline; 16. Intermediate container; 17. First production pipeline; 18. First back pressure valve; 19. First metering device; 20. Second production pipeline; 21. Second back pressure valve; 22. Second metering device; 23. Back pressure valve pressure control pipeline; 24. Back pressure pump; 25. Third deionized water reservoir; 26. First six-way valve; 27. Second six-way valve; 28. Three-way valve; 29. ​​First pressure sensor; 30. Second pressure sensor. DETAILED DESCRIPTION

[0045] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0046] like Figures 1 to 5 As shown, the present invention provides a multi-layer heavy oil reservoir thermal recovery experimental device 1, comprising: an oil reservoir model 110, comprising a first simulated wellbore 111 and a second simulated wellbore 112, at least one oil layer 113 is connected between the first simulated wellbore 111 and the second simulated wellbore 112, each oil layer 113 is provided with at least one pressure measuring point hole 114 and a plurality of temperature measuring point holes 115 arranged at intervals, a pressure detection element is installed in the pressure measuring point hole 114, and a temperature detection element is installed in each temperature measuring point hole 115; a closed chamber 120, on which a confining pressure fluid channel 121 and a first wellbore channel 122 connected to the first simulated wellbore 111 are provided. , a second wellbore channel 123 connected to the second simulated wellbore 112, a containing cavity is formed in the closed warehouse body 120, and the reservoir model 110 is arranged in the containing cavity; a heater 130 is arranged in the containing cavity, and the heater 130 is used to make the inside of the closed warehouse body 120 at the reservoir formation temperature state; the multi-layer heavy oil reservoir thermal recovery experimental device 1 has a first working state and a second working state. In the first working state, the first simulated wellbore 111 and the second simulated wellbore 112 are in the injection state or the production state at the same time; in the second working state, the first simulated wellbore 111 and the second simulated wellbore 112 are in the injection state and the production state respectively.

[0047] The multi-layer heavy oil reservoir thermal recovery experimental device 1 provided in the present application is provided with a closed chamber 120, so as to maintain the reservoir formation simulation in the chamber during the experiment, thereby ensuring the accuracy of the experimental results; different working states can be entered by changing the injection and production states of the first simulated wellbore 111 and the second simulated wellbore 112, so that a variety of experiments can be completed through one experimental device, which is flexible and widely applicable; at least one pressure measuring point hole 114 and a plurality of temperature measuring point holes 115 arranged at intervals are provided on each oil layer 113, so as to facilitate the installation of the detection component, thereby facilitating the parameter acquisition and state monitoring during the experiment.

[0048] Specifically, Figures 1 to 5 As shown, the multi-layer heavy oil reservoir thermal recovery experimental device 1 includes a reservoir model 110, a closed tank body 120 and a heater 130. Figure 2 As shown, the reservoir model 110 includes a first simulated wellbore 111, a second simulated wellbore 112, and at least one oil layer 113 connected between the first simulated wellbore 111 and the second simulated wellbore 112. The reservoir model 110 is specifically a multi-layer sand filling casting model, having an aluminum block shell 116 and an internal casting body, and the model size is 330mm×300mm×80mm. The aluminum block shell 116 is filled with oil sand formed by mixing quartz sand of different meshes (quartz sand meshes are obtained through similar design) and crude oil in proportion. The inner wall of the reservoir model 110 is paved with a certain thickness of clay to simulate the actual formation environment of the multi-layer heavy oil reservoir; the top of the reservoir model 110 is encapsulated with high temperature and high pressure resistant epoxy resin, which can not only meet the experimental high temperature and high pressure conditions, but also achieve macroscopic visualization. The reservoir model 110 is provided with grooves with a radial diameter of 5 mm to 8 mm and a depth of 1.5 mm to 2 mm on all sides. An O-ring with an outer diameter of 240 mm and a line diameter of 1.9 mm is embedded in the groove to increase the adhesion strength between the epoxy resin and the model, so as to improve the overall sealing of the reservoir model 110. At the same time, the O-ring can also play a buffering role during the experiment to avoid hard contact between the epoxy resin and other components. An epoxy resin cover plate is placed between each layer of oil sand and the top epoxy resin to prevent the uncured epoxy resin liquid from entering the oil sand and causing formation damage when pouring the epoxy resin for model packaging. Figure 2 and Figure 3As shown, each oil layer 113 is provided with at least one pressure measuring point hole 114 with an aperture of 12 mm to 15 mm and a plurality of temperature measuring point holes 115 arranged at intervals, which are used to set pressure detection components and temperature detection components as needed, such as by correspondingly installing pressure sensors and thermocouples to realize the monitoring of pressure and temperature changes inside the model; a first simulated wellbore 111 and a second simulated wellbore 112 are provided at both ends of the oil layer 113 inside the reservoir model 110, and the well diameter of each simulated wellbore is 1.5 mm to 3 mm, and each simulated wellbore is connected with each oil layer 113 through a plurality of perforated holes 117, preferably, five perforated holes 117 are provided in each layer, and the aperture is 1.5 mm to 2 mm; both ends of each simulated wellbore are respectively provided with an inlet and outlet connected to the outside of the model, and the aperture is 3 mm to 5 mm, which is used to simulate the vertical well development of multi-layer heavy oil reservoirs. In order to simulate the actual on-site development of an oil field, the reservoir model 110 is placed vertically in the experimental state, that is, the first simulated wellbore 111 and the second simulated wellbore 112 are extended along the gravity direction to truly reflect the impact of gravity differences on development. A visual window 125 can be opened at a corresponding position of the closed warehouse 120, and a monitor can also be set at a corresponding position to facilitate observation of the migration and distribution of fluids in each oil layer 113, and this application does not limit this.

[0049] In the experimental state, the entire closed chamber 120 is filled with high temperature and high pressure resistant confining fluid, which can not only serve as a medium for heating and conduction, but can also be continuously injected through the confining fluid channel 121 to continuously pressurize the inside of the closed chamber 120, thereby providing confining pressure for the model and simulating the confining pressure state of the real reservoir formation. Figure 1 As shown, since the volume of the accommodating chamber is large and the injection speed of the conventional confining pressure pump 4 is slow, a confining pressure fluid fast channel 126 is also provided on the closed warehouse body 120. The confining pressure fluid fast channel 126 is provided with a high-pressure oil pump for one-time rapid filling and extraction of the confining pressure fluid inside the closed warehouse body 120. The confining pressure fluid fast channel 126 can be blocked with a plug during the period from rapid filling to extraction to ensure complete sealing of the interior of the closed warehouse body 120 during the experiment.

[0050] According to one embodiment of the present invention, Figure 1 , Figure 4 and Figure 5 As shown, a visual window 125 is provided on the side wall of the closed chamber 120 close to the reservoir model 110. Under the experimental state, the accommodating cavity is filled with a transparent confining pressure fluid medium, so that the visual window 125 can be used to observe the migration and distribution of the fluid in each oil layer 113. Specifically, the visual window 125 is made of a high temperature and high pressure resistant glass material, so that the migration and distribution of the fluid in the experimental process can be observed and photographed by a camera under the experimental state. Preferably, the confining pressure fluid medium is a high temperature and high pressure resistant transparent dimethyl silicone oil.

[0051] According to one embodiment of the present invention, Figure 1 , Figure 4 and Figure 5 As shown, the closed warehouse body 120 is a cylindrical cavity, the axis of the closed warehouse body 120 is perpendicular to the axis of the first simulated wellbore 111 and the second simulated wellbore 112, there are multiple oil layers 113, and the multiple oil layers 113 are arranged at intervals along the axis direction of the first simulated wellbore 111 or the second simulated wellbore 112, and the closed warehouse body 120 is provided with multiple visual windows 125 corresponding to the multiple oil layers 113 in the circumferential direction. By setting the visual windows 125 corresponding to the oil layers 113, it is convenient to observe and record the migration and distribution of the fluid in each oil layer 113 in detail. Among them, the closed warehouse body 120 is also provided with a pressure measuring channel 124 for the pressure measuring pipeline to pass through and a temperature measuring channel for the temperature measuring pipeline to pass through. In this embodiment, the length of the closed warehouse body 120 is 420mm, the radius is 210mm, and the maximum pressure resistance is 30MPa.

[0052] According to one embodiment of the present invention, Figures 2 to 5 As shown, there are three oil layers 113, and correspondingly, there are three viewing windows 125, two adjacent viewing windows 125 are staggered at 50° along the circumferential direction of the closed warehouse body 120, and the viewing radius of the viewing windows 125 is 30 mm. By staggering two adjacent viewing windows 125 at 50° along the circumferential direction of the closed warehouse body 120, a better observation position is provided for each corresponding oil layer 113.

[0053] According to one embodiment of the present invention, the reservoir model 110 is fixedly connected to the closed chamber 120 via a model bracket 140, the heater 130 is disposed on the side of the reservoir model 110 away from the visual window 125, and a temperature probe 150 for detecting the temperature in the chamber is also disposed between the heater 130 and the reservoir model 110. Specifically, Figure 1As shown, an L-shaped model bracket 140 is fixedly connected inside the closed chamber 120 for placing and fixing the reservoir model 110, and the size of the model bracket 140 is 342 mm×342 mm; the heater 130 is arranged on the side of the reservoir model 110 away from the visual window 125 to prevent the heater 130 from blocking the reservoir model 110 and thus affecting the observation of the fluid migration and distribution law in each oil layer 113; the temperature probe 150 is arranged between the heater 130 and the reservoir model 110 and close to the reservoir model 110, so as to facilitate the timely detection and feedback of the temperature in the closed chamber 120, especially the ambient temperature around the reservoir model 110. Among them, the heater 130 is preferably a continuous heating coil, and its extension direction is the axial direction of the closed chamber 120. Preferably, the heating coils are two radially aligned ones, with a power of 3kW, a heating zone length of 395mm extending into the closed warehouse 120, a non-heating zone length of 65mm located in the wall of the closed warehouse 120, a tube radius of 6mm, and a maximum heating temperature of 200°C. Furthermore, a seal is provided between the heating coil and the closed warehouse 120 to ensure the sealing of the closed warehouse 120. In order to ensure uniform heating, heat convection is formed inside the closed warehouse 120, and the model is effectively heated. The heating coil is arranged on the side of the reservoir model 110 away from the visual window 125 and away from the reservoir model 110, so as to continuously provide a temperature environment through the heat convection formed in the cavity between the reservoir model 110 and the heating coil, thereby effectively simulating the temperature state of the real reservoir formation.

[0054] According to one embodiment of the present invention, the closed bin body 120 includes an axially extending shell and end sealing plates 127 disposed at both ends of the shell. The end sealing plates 127 are provided with a circumferentially closed slide rail structure 128. The slide rail structure 128 divides the end sealing plates 127 into a movable inner plate and a fixed outer plate. The shell is connected to the movable inner plate, and a receiving cavity is formed between the movable inner plate and the shell. The movable inner plate can be circumferentially rotated and locked along the slide rail structure 128. Specifically, as Figure 1 , Figure 4 and Figure 5 As shown, the end sealing plate 127 is connected to the shell through a plurality of stud bolts arranged circumferentially, and a visual window 125 is arranged on the shell. One end sealing plate 127 is provided with a first wellbore channel 122, a second wellbore channel 123 and a pressure measuring channel 124, and is connected to a model bracket 140; the other end sealing plate 127 is provided with a confining pressure fluid channel 121 and a confining pressure fluid fast channel 126, and is connected to a heating coil. Furthermore, in order to reduce the heat transfer between the interior of the chamber and the external environment and maintain the experimental temperature environment in the chamber, a heat preservation cover 129 is arranged outside the shell.

[0055] like Figure 4As shown, in the experimental preparation stage, the movable inner plate can be rotated circumferentially along the slide rail structure 128 until the axes of the first simulated wellbore 111 and the second simulated wellbore 112 are parallel to the horizontal direction and locked, so as to facilitate the assembly of parts and the connection of pipelines; Figure 5 As shown, when entering the experimental stage, the movable inner plate can be rotated circumferentially along the slide rail structure 128 until the axes of the first simulated wellbore 111 and the second simulated wellbore 112 are parallel to the direction of gravity and locked, so as to match the on-site vertical well oil production and make the permeability of multiple oil layers 113 form an anti-rhythm, which is closer to the on-site experiment.

[0056] According to one embodiment of the present invention, Figure 1 As shown, a multi-core connector 160 is provided on the closed chamber 120, and the multi-core connector 160 is electrically connected to a plurality of temperature detection components in each oil layer 113. Specifically, the multi-core connector 160 is provided on the temperature measurement channel, and the multi-core connector 160 is provided to facilitate electrical communication between the temperature detection component and the external monitoring display device.

[0057] like Figure 6As shown, another object of the present invention is a multi-layer heavy oil reservoir thermal recovery experimental system, comprising: the above multi-layer heavy oil reservoir thermal recovery experimental device 1; a confining pressure fluid injection pipeline 2, connected between the confining pressure fluid reservoir 3 and the confining pressure fluid channel 121, and a confining pressure pump 4 is provided on the confining pressure fluid injection pipeline 2; a first steam injection pipeline 5, connected between the first deionized water reservoir 6 and the first wellbore channel 122, and in the direction from the first deionized water reservoir 6 to the first wellbore channel 122, a first steam pump 7, a first steam generator 8, and a first vent valve 9 are sequentially provided on the first steam injection pipeline 5; a second steam injection pipeline 10, connected to the second deionized water reservoir 11 A second steam pump 12, a second steam generator 13, and a second vent valve 14 are sequentially arranged on the second steam injection pipeline 10 between the first steam pump 7 and the second wellbore channel 123, from the second deionized water reservoir 11 to the first wellbore channel 122; a crude oil injection pipeline 15 is provided with an intermediate container 16 for storing crude oil, one end of the crude oil injection pipeline 15 is connected to the first steam injection pipeline 5 between the first steam pump 7 and the first steam generator 8, and the other end of the crude oil injection pipeline 15 is connected to the first steam injection pipeline 5 between the first vent valve 9 and the first wellbore channel 122; deionized water is introduced into the crude oil injection pipeline 15 from the first steam injection pipeline 5 In the state, the intermediate container 16 can pass crude oil into the reservoir model 110; the first production pipeline 17 is provided with a first back pressure valve 18, one end of the first production pipeline 17 is connected to the first steam injection pipeline 5 between the first vent valve 9 and the first wellbore channel 122, and the other end of the first production pipeline 17 is connected to the first metering device 19; the second production pipeline 20 is provided with a second back pressure valve 21, one end of the second production pipeline 20 is connected to the second steam injection pipeline 10 between the second vent valve 14 and the second wellbore channel 123, and the other end of the second production pipeline 20 is connected to the second metering device 22; the back pressure valve pressure control pipeline 23 is provided with a back pressure valve The pump 24, one end of the back pressure valve pressure control pipeline 23 is connected to the third deionized water reservoir 25, and the other end of the back pressure valve pressure control pipeline 23 is connected to the first back pressure valve 18 and the second back pressure valve 21; the crude oil injection pipeline 15 and the first production pipeline 17 are connected to the first steam injection pipeline 5 between the first vent valve 9 and the first wellbore channel 122 through the first six-way valve 26; the second production pipeline 20 is connected to the second steam injection pipeline 10 between the second vent valve 14 and the second wellbore channel 123 through the second six-way valve 27; the crude oil injection pipeline 15 is connected to the first steam injection pipeline 5 between the first steam pump 7 and the first steam generator 8 through the three-way valve 28. Among them, the storage medium in the confining pressure fluid reservoir 3 is dimethyl silicone oil.

[0058] Specifically, the multi-layer heavy oil reservoir thermal recovery experiment system also includes a data monitoring and display module, which is used to monitor the temperature and pressure at different positions inside the closed chamber 120 and the reservoir model 110 in real time during the experiment, and to accurately adjust the experimental pressure in combination with computer software to ensure the smooth progress of the experiment. Figure 6 As shown, preferably, the first six-way valve 26 is connected to a first pressure sensor 29, and the second six-way valve 27 is connected to a second pressure sensor 30. The first pressure sensor 29 is used to measure the flow pressure of the fluid flowing through the first six-way valve 26, and the second pressure sensor 30 is used to measure the flow pressure of the fluid flowing through the second six-way valve 27, so as to accurately control the flow pressure of the input fluid. Further, all kinds of pipelines connected to the multi-layer heavy oil reservoir thermal recovery experimental device 1 are provided with insulation sleeves and heating belts to reduce the energy loss of the medium in the pipeline during the flow, meet the injection conditions of the medium required for the experiment as much as possible, and improve the flow performance of the medium in the pipeline.

[0059] The multi-layer heavy oil reservoir thermal recovery experimental system provided in the present application can truly restore the actual geological conditions of the multi-layer heavy oil reservoir, not only can it simulate the thermal recovery development process of the multi-layer heavy oil reservoir, but also can study the development dynamics and production laws of the single-layer heavy oil reservoir under different conditions, and can even simulate the development of the multi-layer heavy oil reservoir under multiple conditions, including multi-element thermal fluid drive, chemical composite drive, steam foam drive and non-condensate gas auxiliary, etc., which can make up for the shortcomings of the existing experimental devices that only consider single-layer reservoirs or use multi-tubes to simulate multi-layer reservoirs. The experimental system can effectively carry out indoor simulations of different development methods of multi-layer heavy oil reservoirs, and can study the influence of static geological parameters (including the number of interlayers, oil layer 113 thickness distribution, permeability, porosity, etc.) and dynamic injection parameters (including steam dryness, production-injection ratio, periodic injection volume, etc.) of the reservoir on the production effect under different development methods. At the same time, it can also study the temperature evolution law and residual oil distribution in the production process.

[0060] The present invention also provides an experimental method for realizing thermal recovery of multi-layer heavy oil reservoirs by using the above multi-layer heavy oil reservoir thermal recovery experimental system, comprising:

[0061] Step S00, start the confining pressure pump 4, and pass the confining pressure fluid in the confining pressure fluid reservoir 3 into the closed chamber 120 to form the closed chamber 120 into a pressure chamber; turn on the heater 130 to make the interior of the closed chamber 120 at the reservoir formation temperature.

[0062] Step S10, start the back pressure pump 24, and inject the deionized water in the third deionized water reservoir 25 into the back pressure valve pressure control pipeline 23 until the pressure of the first back pressure valve 18 and the second back pressure valve 21 reaches the formation pressure required for the first round of steam stimulation experiment.

[0063] Step S20, adjust the first six-way valve 26 and the three-way valve 28 to connect the first steam pump 7 with the first wellbore channel 122 through the crude oil injection pipeline 15; adjust the second six-way valve 27 to connect the second production pipeline 20 with the second wellbore channel 123; start the first steam pump 7, pass the crude oil in the intermediate container 16 into the reservoir model 110, and continuously pressurize the closed warehouse body 120 through the confining pressure pump 4. When crude oil appears in the second metering device 22, turn off the first steam pump 7 and the back pressure pump 24.

[0064] Step S30, adjust the three-way valve 28, connect the first steam pump 7 and the first steam generator 8, set the steam temperature of the first steam generator 8 to the steam saturation temperature under the formation pressure corresponding to step S10, start the first steam pump and the first steam generator 8, and use the first steam generator 8 to inject the first steam into the steam in the pipeline 5 to hold the steam pressure to the formation pressure required for the first round of steam injection experiment; set the steam temperature of the second steam generator 13 to the steam saturation temperature under the formation pressure corresponding to step S10, start the second steam pump 12 and the second steam generator 13, and use the second steam generator 13 to inject the second steam into the pipeline 5 to hold the steam pressure to the formation pressure required for the first round of steam injection experiment; The steam in 10 is pressurized to the formation pressure required for the first round of steam injection experiment; the first six-way valve 26 is adjusted to connect the first steam injection pipeline 5 with the first wellbore channel 122, and the second six-way valve 27 is adjusted to connect the second steam injection pipeline 10 with the second wellbore channel 123, so as to simultaneously introduce steam into the first wellbore channel 122 and the second wellbore channel 123, and the closed warehouse 120 is continuously pressurized by the confining pressure pump 4. When the steam injection time reaches the experimental steam injection time requirement, the first steam pump 7, the first steam generator 8, the second steam pump 12, the second steam generator 13 and all valves are closed to shut down the well.

[0065] Step S40, after the soaking time requirement is reached, start the back pressure pump 24, and inject the deionized water in the third deionized water reservoir 25 into the back pressure valve pressure control pipeline 23, until the pressure of the first back pressure valve 18 and the second back pressure valve 21 are at the formation pressure required for the first round of steam stimulation experiment; adjust the first six-way valve 26 to connect the first production pipeline 17 with the first wellbore channel 122, and adjust the second six-way valve 27 to connect the second production pipeline 20 with the second wellbore channel 123, so that the fluid in the reservoir model 110 flows into the first meter 19 and the second meter 22 at the same time. When the fluid in the first meter 19 and the second meter 22 no longer increases, close all valves and the back pressure pump 24, and the first round of steam stimulation experiment is completed.

[0066] Step S50, repeating steps S10, S30, S40 for multiple times to conduct multiple rounds of steam stimulation experiments, wherein the pressures of the first back pressure valve 18 and the second back pressure valve 21 are correspondingly set to the formation pressures required for each round of steam stimulation experiments.

[0067] Step S60, start the back pressure pump 24, and inject the deionized water in the third deionized water reservoir 25 into the back pressure valve pressure control pipeline 23 until the pressure of the second back pressure valve 21 reaches the formation pressure required for the steam flooding experiment.

[0068] Step S70, adjust the three-way valve 28, connect the first steam pump 7 and the first steam generator 8, set the steam temperature of the first steam generator 8 to the temperature required for the steam drive experiment, start the first steam pump 7 and the first steam generator 8, and use the first steam generator 8 to pressurize the steam in the first steam injection pipeline 5 to the formation pressure required for the steam drive experiment.

[0069] Step S80, adjust the first six-way valve 26 to connect the first steam injection pipeline 5 with the first wellbore channel 122, and introduce steam into the first wellbore channel 122; adjust the second six-way valve 27 to connect the second production pipeline 20 with the second wellbore channel 123, and allow the fluid in the reservoir model 110 to flow into the second metering device 22.

[0070] Step S90, when the temperature of each oil layer 113 near the second simulated wellbore 112 approaches the steam temperature and the crude oil accounts for no more than 2% of the fluid flowing into the second metering device 22, the first steam generator 8 is closed, the first vent valve 9 is opened, and after the deionized water in the first deionized water reservoir 6 reduces the temperature of the steam generator to room temperature, the first steam pump 7 is closed, the back pressure pump 24 is closed, and the pressure of the second back pressure valve 21 is at atmospheric pressure. After the closed bin 120 is depressurized through the second back pressure valve 21, the heater 130 is closed.

[0071] Specifically, before step S00, the preparation work including the production of reservoir model 110, assembly of parts, connection of pipelines, and sealing test is also included. Among them, the production of reservoir model 110 includes: firstly, the similarity design of the model is carried out, and on the basis of the similarity design, the permeability of the model is subjected to motion constraints, and the motion similarity test is carried out using the Fuchs-Hymer law of non-Darcy flow (Reynolds number (Re) ≤ 1 to 10 is Darcy flow). If the similarity design result is satisfied, the similarity design result is adopted, and if it is not satisfied, the constrained permeability needs to be adopted. Combined with the experimental design calculation, the experimental parameters are finally determined. The experimental parameters mainly include basic model parameters such as the total thickness of the model, permeability, and thickness of the oil layer 113, and experimental operation parameters such as steam injection volume, injection time, well soaking time, and steam injection speed. Among them, the weighted average permeability data table of the reservoir is shown in Table 1, and the experimental parameter design result table is shown in Table 2; secondly, the quartz sand (40-60 mesh, 60-80 mesh) selected for the experiment is determined, and then the heavy oil and quartz sand of different mesh sizes are mixed according to the designed proportion. The prepared oil sand is prepared and filled in anti-rhythmic distribution. During the sand filling process, the inner wall of the model is too smooth, so it needs to be roughened with clay. In this embodiment, the thickness of the oil sand is 5 cm. In order to make the measurement result relatively more accurate, during the sand filling process, it is necessary to install a thermocouple and a pressure sensor for measuring the temperature and pressure of each oil layer 113 at a position 2.5 cm away from the bottom of each oil layer 113 (the middle part of the thickness of the oil sand) according to the design point, so as to facilitate the clarification of the temperature evolution law and the monitoring of the pressure change during the experiment. Then, the epoxy resin cover plate prepared in advance is placed above the sand body to prevent the epoxy resin from entering the sand body during the pouring process, destroying the sand body structure and blocking the perforation holes 117; and the gap between the epoxy resin cover plate and the sand body is sealed again with clay around it. Finally, the high temperature and high pressure resistant epoxy resin is filled into the mold by 1 cm to encapsulate the entire model, and it is ready to be solidified. Among them, the ratio of heavy oil and quartz sand is calculated according to the porosity of the target block reservoir, and the sand volume is calculated by the model size. It is assumed that all pores are crude oil in the target block, and the pore volume is the crude oil volume.

[0072] Table 1 Reservoir weighted average permeability data table

[0073]

[0074]

[0075] Among them, model similarity designs include:

[0076] A similar design is performed on the permeability, and K p =0.8μm 2 Perform the calculation:

[0077]

[0078] Among them, the geometric similarity ratio is: The permeability of a similar model is: Apply motion constraints to the permeability:

[0079] Reynolds number:

[0080] Table 2 Experimental parameter design results

[0081]

[0082]

[0083] Among them, the pipeline connection is carried out in accordance with the composition of the multi-layer heavy oil reservoir thermal recovery experimental system. After the connection is completed, all inlet and outlet pipelines are insulated and heated using insulation sleeves and heating belts, and then the closed warehouse body 120 is sealed to enter the sealing test. Combined with the experimental pressure, nitrogen or air under corresponding pressure conditions is selected to be injected, and it is left to stand for more than 24 hours. The pressure change is observed through the data monitoring display module. If the pressure change is less than 0.1MPa, it is considered that the sealing is good; at the same time, the temperature display is observed. If the temperature is roughly the same as the room temperature, it is considered that the temperature display is normal, and the next experiment can be carried out.

[0084] In step S00, the confining fluid is first introduced into the closed chamber 120 through the confining fluid fast channel 126, and then the channel is closed, and the confining fluid is introduced through the confining fluid channel 121 to continuously pressurize the interior of the closed chamber 120. The reservoir formation temperature is 40°C, which is monitored by the temperature probe 150 and the temperature detection member in the temperature measuring point hole 115 inside the reservoir model 110.

[0085] In step S10, the formation pressure required for the first round of steam stimulation experiment is the original formation pressure of 9 MPa.

[0086] In step S20, the output power of the first steam pump 7 is adjusted to control the crude oil introduction rate to 2 ml / min to achieve smooth oil injection.

[0087] In step S30, the rate of introducing steam into the first wellbore channel 122 and the second wellbore channel 123 is set to 10 ml / min, the injection time is set to 15 min, and the soaking time is set to 2 min.

[0088] In step S40, during the adjustment of the first six-way valve 26 and the second six-way valve 27, the operation needs to be slow to prevent the internal pressure from being too high and causing liquid spraying.

[0089] In step S50, steps S10, S30, and S40 are repeated 5 times in total. The required formation pressures in the 5 rounds of steam huff and puff experiments are 8 MPa, 7 MPa, 6 MPa, 5 MPa, and 5 MPa, respectively. Among them, photos are taken before each round of huff and puff injection, during well soaking, and after huff and puff production to facilitate comparison of the fluid distribution inside the model in different time periods.

[0090] In step S60, the formation pressure required for the steam flooding experiment is set to 5 MPa.

[0091] In step S70, the temperature required for the steam flooding experiment is set to 264°C.

[0092] In step S80, the rate of introducing steam into the first wellbore channel 122 is set to 13.3 ml / min.

[0093] During the steam drive experiment, a two-minute drive video was taken every half hour, and photos were taken every 10 minutes to facilitate later comparative analysis.

[0094] The experimental results of thermal recovery of multi-layer heavy oil reservoirs are as follows: Figures 7 to 10 As shown in the figure, the light gray part is the heating cavity, and the dark gray part is the steam cavity. Specifically, the development pattern of the heating cavity in the steam intake and exhaust stage is ellipsoid → lower cone → inverted truncated cone, and the development pattern of the heating cavity in the steam drive stage is lower cone → inverted truncated cone; for general steam injection, the uppermost heating cavity accounts for the highest proportion. After the drive, the temperature of the uppermost layer gradually exceeds the steam saturation temperature, and a steam cavity appears. During the whole process, the uppermost layer is the first to steam channel, and then the proportion of the heating cavity in the lower layer begins to decrease; and because the uppermost layer is the dominant layer under general steam injection, the steam absorption is larger, so the heating cavity expands faster and accounts for a higher proportion.

[0095] According to one embodiment of the present invention, in order to prevent the epoxy resin encapsulating the reservoir model 110 from cracking, the difference between the internal pressure of the closed chamber 120 and the crude oil flow pressure and steam flow pressure entering the reservoir model 110 is no more than 1MPa, that is, the difference between the external confining pressure fluid pressure of the reservoir model 110 and the crude oil flow pressure and steam flow pressure entering the reservoir model 110 is no more than 1MPa. If it is found during the experiment that the internal pressure of the reservoir model 110 rises too fast during steam injection, making it difficult for the confining pressure to keep up, the injection amount, injection speed, etc. can be adjusted in real time to ensure that the internal and external pressure difference does not exceed 1MPa at all times.

[0096] The experimental method for thermal recovery of multi-layer heavy oil reservoirs provided in the present application is based on a similar design and also carries out a similar design of permeability taking into account motion constraints. Therefore, the experimental method can more realistically and effectively simulate the thermal recovery development dynamics and production laws of multi-layer heavy oil reservoirs, and provide strong support for reservoir engineering analysis of actual thermal recovery development of multi-layer heavy oil reservoirs.

[0097] The above are only several embodiments of the present invention. Those skilled in the art may make various changes or modifications to the embodiments of the present invention based on the contents disclosed in the application documents without departing from the spirit and scope of the present invention.

Claims

1. A thermal recovery experimental device for a multi-layer heavy oil reservoir, characterized in that: include: The reservoir model comprises a first simulated wellbore and a second simulated wellbore, wherein at least one oil layer is connected between the first simulated wellbore and the second simulated wellbore, each of the oil layers is provided with at least one pressure measuring point hole and a plurality of temperature measuring point holes arranged at intervals, a pressure detection element is installed in the pressure measuring point hole, and a temperature detection element is installed in each of the temperature measuring point holes; a closed warehouse body, on which a confining pressure fluid channel, a first wellbore channel connected to the first simulated wellbore, and a second wellbore channel connected to the second simulated wellbore are provided, and a receiving cavity is formed in the closed warehouse body, and the reservoir model is arranged in the receiving cavity; A heater is disposed in the accommodating cavity, and the heater is used to keep the interior of the closed chamber at a reservoir formation temperature; The multi-layer heavy oil reservoir thermal recovery experimental device has a first working state and a second working state. In the first working state, the first simulated wellbore and the second simulated wellbore are in an injection state or a production state at the same time; in the second working state, the first simulated wellbore and the second simulated wellbore are in an injection state and a production state, respectively.

2. The multi-layer heavy oil reservoir thermal recovery experimental device according to claim 1, characterized in that: A visual window is provided on the side wall of the closed chamber close to the reservoir model. Under experimental conditions, the accommodating cavity is filled with a transparent confining pressure fluid medium, so that the visual window can be used to observe the migration and distribution of the fluid in each oil layer.

3. The multi-layer heavy oil reservoir thermal recovery experimental device according to claim 2, characterized in that: The closed warehouse body is a cylindrical cavity, the axis of the closed warehouse body is perpendicular to the axis of the first simulated wellbore and the second simulated wellbore, there are multiple oil layers, and the multiple oil layers are arranged at intervals along the axis direction of the first simulated wellbore or the second simulated wellbore, and the closed warehouse body is provided with multiple visible windows corresponding to the multiple oil layers in a one-to-one manner along the circumferential direction.

4. The multi-layer heavy oil reservoir thermal recovery experimental device according to claim 3 is characterized in that: There are three oil layers, and correspondingly, there are three visual windows. Two adjacent visual windows are staggered at 50° along the circumferential direction of the closed warehouse body, and the visual radius of the visual window is 30 mm.

5. The multi-layer heavy oil reservoir thermal recovery experimental device according to claim 2, characterized in that: The reservoir model is fixedly connected to the closed chamber body via a model bracket, the heater is arranged on a side of the reservoir model away from the visual window, and a temperature probe for detecting the temperature in the chamber is also arranged between the heater and the reservoir model.

6. The multi-layer heavy oil reservoir thermal recovery experimental device according to claim 1, characterized in that: The closed bin body includes an axially extending shell and end sealing plates arranged at both ends of the shell, and a circumferentially closed slide rail structure is arranged on the end sealing plate. The slide rail structure divides the end sealing plate into a movable inner plate and a fixed outer plate. The shell is connected to the movable inner plate, and the accommodating cavity is formed between the movable inner plate and the shell. The movable inner plate can rotate circumferentially and be locked along the slide rail structure.

7. The multi-layer heavy oil reservoir thermal recovery experimental device according to claim 1, characterized in that: The closed warehouse body is provided with a multi-core connector, and the multi-core connector is electrically connected to a plurality of temperature detection components in each of the oil layers.

8. A multi-layer heavy oil reservoir thermal recovery experimental system, characterized in that: include: The multi-layer heavy oil reservoir thermal recovery experimental device according to any one of claims 1 to 7; A confining pressure fluid injection pipeline is connected between the confining pressure fluid reservoir and the confining pressure fluid channel, and a confining pressure pump is provided on the confining pressure fluid injection pipeline; A first steam injection pipeline is connected between the first deionized water reservoir and the first wellbore channel, and a first steam pump, a first steam generator, and a first vent valve are sequentially arranged on the first steam injection pipeline in a direction from the first deionized water reservoir to the first wellbore channel; A second steam injection pipeline is connected between the second deionized water reservoir and the second wellbore channel, and a second steam pump, a second steam generator, and a second vent valve are sequentially arranged on the second steam injection pipeline in a direction from the second deionized water reservoir to the first wellbore channel; a crude oil injection pipeline, on which an intermediate container for storing crude oil is arranged, one end of the crude oil injection pipeline is connected to the first steam injection pipeline between the first steam pump and the first steam generator, and the other end of the crude oil injection pipeline is connected to the first steam injection pipeline between the first vent valve and the first wellbore channel; when deionized water is passed from the first steam injection pipeline to the crude oil injection pipeline, the intermediate container can pass crude oil into the reservoir model; a first production pipeline, on which a first back pressure valve is arranged, one end of the first production pipeline is connected to the first steam injection pipeline between the first vent valve and the first wellbore channel, and the other end of the first production pipeline is connected to a first meter; a second production pipeline, on which a second back pressure valve is arranged, one end of the second production pipeline is connected to the second steam injection pipeline between the second vent valve and the second wellbore channel, and the other end of the second production pipeline is connected to a second meter; A back-pressure valve pressure control pipeline, on which a back-pressure pump is arranged, one end of the back-pressure valve pressure control pipeline is connected to a third deionized water reservoir, and the other end of the back-pressure valve pressure control pipeline is connected to the first back-pressure valve and the second back-pressure valve; The crude oil injection pipeline and the first production pipeline are connected to the first steam injection pipeline between the first vent valve and the first wellbore channel through a first six-way valve; the second production pipeline is connected to the second steam injection pipeline between the second vent valve and the second wellbore channel through a second six-way valve; the crude oil injection pipeline is connected to the first steam injection pipeline between the first steam pump and the first steam generator through a three-way valve.

9. An experimental method for realizing thermal recovery of multi-layer heavy oil reservoirs using the multi-layer heavy oil reservoir thermal recovery experimental system as claimed in claim 8, characterized in that: include: Step S00, turning on the confining pressure pump, passing the confining pressure fluid in the confining pressure fluid reservoir into the closed warehouse, so that the closed warehouse forms a pressure warehouse; turning on the heater, so that the interior of the closed warehouse is at the reservoir formation temperature; Step S10, start the back pressure pump, and inject the deionized water in the third deionized water reservoir into the back pressure valve pressure control pipeline until the pressure of the first back pressure valve and the second back pressure valve reaches the formation pressure required for the first round of steam stimulation experiment; Step S20, adjusting the first six-way valve and the three-way valve so that the first steam pump is connected to the first wellbore channel through the crude oil injection pipeline; adjusting the second six-way valve so that the second production pipeline is connected to the second wellbore channel; starting the first steam pump to pass the crude oil in the intermediate container into the reservoir model, and continuously pressurizing the closed warehouse body through the confining pressure pump, and when crude oil appears in the second metering device, closing the first steam pump and the back pressure pump; Step S30, adjusting the three-way valve, connecting the first steam pump and the first steam generator, setting the steam temperature of the first steam generator to the steam saturation temperature under the formation pressure corresponding to step S10, turning on the first steam pump and the first steam generator, and using the first steam generator to inject the first steam into the steam pipeline to hold the steam pressure to the formation pressure required for the first round of steam injection experiment; setting the steam temperature of the second steam generator to the steam saturation temperature under the formation pressure corresponding to step S10, turning on the second steam pump and the second steam generator, and using the second steam generator to inject the first steam into the steam pipeline to hold the steam pressure to the formation pressure required for the first round of steam injection experiment; setting the steam temperature of the second steam generator to the steam saturation temperature under the formation pressure corresponding to step S10, turning on the second steam pump and the second steam generator, and using the second steam generator to inject the first steam into the steam pipeline to hold the steam pressure to the formation pressure required for the first round of steam injection experiment The steam in the second steam injection pipeline is pressurized to the formation pressure required for the first round of steam huff-and-puff experiment; the first six-way valve is adjusted to connect the first steam injection pipeline with the first wellbore channel, and the second six-way valve is adjusted to connect the second steam injection pipeline with the second wellbore channel, so as to simultaneously introduce steam into the first wellbore channel and the second wellbore channel, and the closed chamber is continuously pressurized by the confining pressure pump; when the steam injection time reaches the experimental steam injection time requirement, the first steam pump, the first steam generator, the second steam pump, the second steam generator and all valves are closed to shut off the well; Step S40: after the soaking time requirement is reached, the back-pressure pump is turned on, and the deionized water in the third deionized water reservoir is injected into the back-pressure valve pressure control pipeline, until the pressure of the first back-pressure valve and the second back-pressure valve is at the formation pressure required for the first round of steam stimulation experiment; the first six-way valve is adjusted to connect the first production pipeline with the first wellbore channel, and the second six-way valve is adjusted to connect the second production pipeline with the second wellbore channel, so that the fluid in the reservoir model flows into the first meter and the second meter at the same time; when the fluid in the first meter and the second meter no longer increases, all valves and the back-pressure pump are closed, and the first round of steam stimulation experiment is completed; Step S50, repeating steps S10, S30, and S40 for multiple times to perform multiple rounds of steam stimulation experiments, wherein the pressures of the first back pressure valve and the second back pressure valve are correspondingly set to the formation pressures required for each round of steam stimulation experiments; Step S60, start the back pressure pump to inject the deionized water in the third deionized water reservoir into the back pressure valve pressure control pipeline until the pressure of the second back pressure valve reaches the formation pressure required for the steam flooding experiment; Step S70, adjusting the three-way valve to connect the first steam pump and the first steam generator, setting the steam temperature of the first steam generator to the temperature required for the steam drive experiment, starting the first steam pump and the first steam generator, and using the first steam generator to inject the first steam into the steam in the pipeline to hold the pressure to the formation pressure required for the steam drive experiment; Step S80, adjusting the first six-way valve to connect the first steam injection pipeline with the first wellbore channel, and introducing steam into the first wellbore channel; adjusting the second six-way valve to connect the second production pipeline with the second wellbore channel, and allowing the fluid in the reservoir model to flow into the second meter; Step S90, when the temperature of each oil layer near the second simulated wellbore approaches the steam temperature and the crude oil accounts for no more than 2% of the fluid flowing into the second metering device, the first steam generator is closed, the first vent valve is opened, and after the deionized water in the first deionized water reservoir reduces the temperature of the steam generator to room temperature, the first steam pump is closed, the back pressure pump is closed, the pressure of the second back pressure valve is at atmospheric pressure, and after the closed chamber is depressurized through the second back pressure valve, the heater is closed.

10. The experimental method according to claim 9, characterized in that: The difference between the internal pressure of the closed chamber and the crude oil flow pressure and steam flow pressure entering the reservoir model is no more than 1 MPa.

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