Physical simulation device and method for in-situ chemical heat drive of super-deep low-permeability heavy oil reservoir

Abstract

This invention provides a physical simulation device and method for internalized thermal flooding in ultra-deep, low-permeability heavy oil reservoirs. The device includes a multi-directional temperature and pressure simulation system with a high-pressure vessel to simulate temperature and pressure conduction at different locations deep within the reservoir; a chemical injection system to simulate the injection process of chemicals from the wellhead; a bicomponent high-energy chemical reaction simulation system to simulate the reaction process of bicomponent chemicals in the near-wellbore zone; and a data acquisition system to collect temperature and pressure changes during the experiment and transmit the collected data to an external computer. This physical simulation device and method for internalized thermal flooding in ultra-deep, low-permeability heavy oil reservoirs studies the reaction conditions of high-energy chemicals in different reservoirs by simulating the injection of high-energy chemicals into the reservoir and the exothermic and energy-enhancing oil displacement processes within the reservoir. It clarifies the heat transfer laws, the energy enhancement laws of the generated products, and the changes in oil displacement efficiency.

Description

Technical Field

[0001] This invention relates to the field of physical simulation technology for heavy oil development, and in particular to a physical simulation device and method for internal thermal flooding of ultra-deep, low-permeability heavy oil reservoirs. Background Technology

[0002] In ultra-deep, low-permeability heavy oil reservoirs, steam injection and steam drive processes suffer from significant heat losses at the surface and in the wellbore due to the large reservoir depth. Low reservoir permeability also prevents the formation of steam chambers within the reservoir, resulting in extremely low thermal utilization and poor development outcomes. Injecting green, non-toxic, and non-corrosive high-energy chemical agents into the reservoir is a novel development technology. These high-energy chemicals react within the reservoir to generate high heat and large amounts of gas (N2, CO2), significantly improving the utilization and recovery rates of ultra-deep, low-permeability heavy oil reservoirs. The heating method for heavy oil reservoirs is changed from surface heating to in-situ heat generation within the reservoir, effectively reducing heat loss and significantly improving thermal utilization.

[0003] Chinese patent application CN202011582084.6 discloses a variable diameter core holder, which is sequentially connected to a first plug, a first pad, a first core cylinder, a second core cylinder, a second pad, and a second plug. The first plug and the first pad have a fluid channel connected to the first core cylinder at their axial positions. The first plug is connected to a tapered sleeve, and the first cylinder is connected to the tapered sleeve. The core is placed in an annular pressure cavity. A cross-shaped guide groove is engraved at the end of the first pad that contacts the core. A transition tapered sleeve is provided in both the first and second core cylinders. The first core cylinder is connected to the transition tapered sleeve, and an annular sealing ring is provided on the first cylinder. The second core cylinder is connected to the second transition tapered sleeve, and an annular sealing ring is provided on the second core cylinder.

[0004] Chinese patent application CN202011007282.X discloses a high-temperature resistant core holder and a core temperature tracking heating system. The high-temperature resistant core holder includes: a vessel body with a cavity; the vessel body has an upper opening and a bottom wall below the cavity; a copper sleeve installed inside the cavity; the cavity forming a confining pressure chamber outside the copper sleeve; an upper plug extending into the upper end of the copper sleeve; the upper plug having an input interface, a temperature detection channel, and an ignition heating rod; the temperature detection channel for mounting a temperature measuring element; a first graphite sealing ring sealing the upper plug and the inner wall of the copper sleeve; a lower plug extending into the lower end of the copper sleeve; an upper top block fixedly installed on the upper end of the vessel body; the upper top block fitting over the upper plug and pressing the first graphite sealing ring tightly; and a third graphite sealing ring being pressed tightly between the upper top block and the inner wall of the vessel body's cavity.

[0005] Chinese patent application CN201710932760.X discloses a high-temperature, high-pressure core holder, a device used in oil and gas development, nuclear waste storage, and geothermal development for conducting high-temperature, high-pressure core permeation experiments. The device consists of a pressure-bearing cylinder, an axial-pressure piston, a core seat, a tapered core, an axial-pressure plug, a water-cooling device, a ventilation device, a hydraulic device, a sealing copper ring, and a sealing retaining ring. The inner wall of the core seat fits snugly against the tapered core wall and has the same taper. The axial-pressure piston applies axial pressure to the larger end face of the tapered core, subjecting it to axial force. The inner wall of the core seat generates a reaction force against the tapered core wall; this reaction force is the confining pressure. The device can be used with a tubular furnace and is equipped with a water-cooling device to ensure airtightness at high temperatures and the sealing of the hydraulic system. It also includes a ventilation system for testing core permeability and creating the experimental gas atmosphere.

[0006] The existing technologies described above differ significantly from this invention and cannot achieve the goal of simulating heat generation and gas-driven oil displacement within reservoirs using high-energy chemical agents. The aforementioned Chinese invention patents cannot monitor temperature changes in different directions of the core sample, nor can they simulate the lateral and longitudinal heat transfer patterns within the reservoir; they also cannot monitor pressure changes within the reservoir or study the variation in the amount of gas produced by the high-energy chemical agent reaction. Furthermore, the aforementioned patents are not applicable to the physical simulation of internalized thermal flooding in ultra-deep, low-permeability heavy oil reservoirs and fail to solve the technical problems we aim to address. Therefore, we have invented a new physical simulation device and method for internalized thermal flooding in ultra-deep, low-permeability heavy oil reservoirs. Summary of the Invention

[0007] The purpose of this invention is to provide a physical simulation device and method for internalized thermal flooding of ultra-deep, low-permeability heavy oil reservoirs, which clarifies the heat transfer law, the energy enhancement law of the generated products, and the change law of oil displacement efficiency.

[0008] The objective of this invention can be achieved through the following technical measures: a physical simulation device for internalized thermal flooding of ultra-deep, low-permeability heavy oil reservoirs. This device includes a reservoir multi-directional temperature and pressure simulation system, a bicomponent high-energy chemical agent reaction simulation system, a chemical agent injection system, and a data acquisition system. The reservoir multi-directional temperature and pressure simulation system has a high-pressure container to simulate the temperature and pressure conduction patterns at different locations in the deep reservoir. The chemical agent injection system is connected to the inlet outside the high-pressure container to simulate the injection process of the chemical agent from the wellhead. The bicomponent high-energy chemical agent reaction simulation system is located at the inlet inside the high-pressure container to simulate the reaction process of the bicomponent chemical agent in the near-wellbore zone. The data acquisition system is connected to the reservoir multi-directional temperature and pressure simulation system and the bicomponent high-energy chemical agent reaction simulation system to collect temperature and pressure changes during the experiment and transmit the collected data to an external computer.

[0009] The objective of this invention can also be achieved through the following technical measures:

[0010] The physical simulation device for thermal flooding of ultra-deep, low-permeability heavy oil reservoirs also includes an outlet backpressure tracking control system. This system is connected to the outside of the outlet end of the high-pressure vessel to control the outflow rate of the produced fluid and prevent blowouts.

[0011] The outlet backpressure tracking control system includes a high-precision backpressure valve and a backpressure tracking pump. The high-precision backpressure valve is connected to the outside of the outlet end of the high-pressure vessel and to the backpressure tracking pump. The backpressure tracking pump is connected to the data acquisition system. The tracking pressure of the backpressure tracking pump is set to be 0.2 MPa higher than the internal pressure of the high-pressure vessel detected by the data acquisition system. The backpressure tracking pump is applied to the high-precision backpressure valve. Under the action of the tracking pressure, the reaction products flow out smoothly from the outlet of the high-precision backpressure valve.

[0012] The chemical agent injection system includes a high-precision injection pump and a chemical agent filling intermediate container. The high-precision injection pump is connected to the chemical agent filling intermediate container, which is connected to the bicomponent high-energy chemical agent reaction simulation system. The high-precision injection pump sequentially injects crude oil, chemical agent A, chemical agent B, and hot water into the bicomponent high-energy chemical agent reaction simulation system through the chemical agent filling intermediate container.

[0013] The dual-component high-energy chemical agent reaction simulation system includes a small-sized core with similar or identical reservoir properties and a core clamping device. The core clamping device is used to hold the small-sized core. After the small-sized core is saturated with crude oil, chemical agent A is injected first, followed by chemical agent B, and finally hot water above 70°C is injected. When the injected hot water raises the temperature at the inlet end of the small-sized core to above 60°C, it triggers the reaction between chemical agent A and chemical agent B in the small-sized core, releasing a large amount of heat and gas, simulating the initiation reaction process of high-energy chemical agents in the near-wellbore zone.

[0014] The core clamping device has an inner ceramic tube and an outer steel tube.

[0015] The bicomponent high-energy chemical agent reaction simulation system comes into contact with the large-size core of the reservoir multi-directional temperature and pressure simulation system, which facilitates the transfer of reaction heat to the large-size core of the reservoir multi-directional temperature and pressure simulation system.

[0016] The reservoir multi-directional temperature and pressure simulation system includes the large-size core and the high-pressure container. The high-pressure container is used to hold the large-size core. The high heat released by the reaction in the binary high-energy chemical agent reaction simulation system is conducted to the large-size core, causing the temperature at the inlet end of the large-size core to rise to over 200°C, triggering the reaction of chemical agent A transmitted to the large-size core by the binary high-energy chemical agent reaction simulation system.

[0017] The high-pressure vessel is made of 32CrMn4 steel, which meets the requirements for temperature resistance above 300℃ and pressure resistance above 50MPa.

[0018] The large core has a diameter of 30cm and a length of more than 30cm; a cylindrical hole with a diameter of 2.52cm and a depth of 5.0cm was drilled at the center of the large core.

[0019] The data acquisition system includes multiple small-sized core temperature sensors, multiple large-sized core temperature sensors, and a pressure sensor. The multiple small-sized core temperature sensors are connected to the small-sized core and collect temperature changes during the reaction process of the small-sized core, transmitting the collected temperature data to an external computer. The pressure sensor is located at the top of the high-pressure vessel. The multiple large-sized core temperature sensors are connected to the large-sized core and collect temperature changes at different locations in the reservoir, both laterally and longitudinally, during the reaction of chemical agent A in the large-sized core, transmitting the temperature data to an external computer. The pressure sensor collects pressure data within the high-pressure vessel and transmits the pressure data to an external computer.

[0020] After receiving temperature and pressure data, the external computer detects the starting temperature of chemical agent A after the injection of chemical agent B; it records the temperature and pressure changes of chemical agent A in the near-wellbore zone (i.e., the small-sized core) and the temperature and pressure changes of chemical agent A in the deep formation (i.e., the large-sized core); based on the collected data, the computer calculates the amount of heat generated by the reaction of chemical agent A and the heat conduction speed in the large-sized core, and scales it up proportionally to the reservoir to calculate the heating radius of chemical agent A in the reservoir under different injection volumes.

[0021] The objective of this invention can also be achieved through the following technical measures: a student-led physical simulation method for internalizing thermal flooding in ultra-deep, low-permeability heavy oil reservoirs. This method employs a student-led physical simulation device for internalizing thermal flooding in ultra-deep, low-permeability heavy oil reservoirs, comprising:

[0022] Step 1: Prepare a small core sample, dry it, and then measure the core volume V. t(1) and weigh m 0(1) ;

[0023] Step 2: Prepare a large-size core. Drill a hole at one end of the large-size core with a diameter equal to the diameter of the core holding device in the bicomponent high-energy chemical agent reaction simulation system, and a depth of 5.0 cm. After drilling and drying, the core volume V t(2) and weigh m 0(2) ;

[0024] Step 3: Vacuum-saturate small and large core samples with simulated formation water, and weigh them separately (m). 1(1) and m 1(2) Calculate pore volume and porosity;

[0025] Step 4: Oil-driven water displacement to create bound water;

[0026] Step 5: Place the small and large cores into the thermal flooding physical simulation device for ultra-deep, low-permeability heavy oil reservoirs and insert temperature sensors.

[0027] Step 6: Inject chemical agent A using the chemical agent injection system at a rate of 0.5 PV; record the outlet liquid production rate and outlet oil production rate at different time intervals during the injection process.

[0028] Step 7, set the outlet back pressure;

[0029] Step 8: Inject 0.1 PV of chemical agent B into a small core using the chemical agent injection system, and record the temperature and pressure changes during the injection process;

[0030] Step 9: Simulate the near-wellbore zone oil displacement process;

[0031] Step 10: Simulate the deep formation oil displacement process;

[0032] Step 11: After the pressure and temperature are balanced, release the back pressure at the outlet, record the final liquid production and oil production Vo(t), and calculate the oil displacement efficiency.

[0033] The objective of this invention can also be achieved through the following technical measures:

[0034] In step 3, the formulas for calculating pore volume and porosity are as follows:

[0035]

[0036]

[0037] Where: m0—mass of the dry rock sample, g;

[0038] m1—mass of the rock sample after saturation with experimental water, in grams;

[0039] ρ w —The density of the experimental water used to saturate the rock sample at the measured temperature, in g / cm³ 3 ;

[0040] V p —Effective pore volume of rock sample, cm 3 ;

[0041] V t —Total volume of rock sample, cm 3;

[0042] φ—Porosity of rock sample, %.

[0043] In step 4, crude oil is used to displace small and large core samples saturated with formation water until no more water is emitted from the core outlet, thus reaching the bound water state. The water volumes Vw1 and Vw2 displaced by the small and large core samples are recorded, and the bound water saturation is calculated.

[0044] In step 4, the bound water saturation is calculated according to equation (3):

[0045]

[0046] In the formula:

[0047] S wi —Bound water saturation, %;

[0048] V p —Effective pore volume of rock sample, cm 3 ;

[0049] V w —The volume of water displaced from the rock, in cm³ 3 .

[0050] In step 7, the back pressure tracking pump of the outlet back pressure tracking control system is set to track a pressure 0.2 MPa higher than the pressure inside the high-pressure vessel in the reservoir multi-directional temperature and pressure simulation system detected by the pressure sensor in the data acquisition system, and automatic tracking is performed.

[0051] In step 9, 0.1 PV of high-temperature hot water is injected into the small core using a chemical injection system, and high-energy chemical agents A and B in the small core begin to react chemically; the temperature, pressure, outlet liquid production, and outlet oil production are recorded at different time intervals during the injection process.

[0052] In step 10, the heat from the reaction of the high-energy chemical agent in the small core is transferred to the large core. After the temperature at the inlet end of the large core reaches 200°C, the chemical agent A in the large core reacts spontaneously and continuously moves towards the outlet end. The chemical agent A generates high heat to reduce the viscosity of crude oil in the large core, while generating a large amount of gas to displace the crude oil. The temperature, pressure, outlet liquid production, and outlet oil production Vo(t) at different time intervals during the reaction process are recorded.

[0053] In step 11, the oil displacement efficiency is calculated according to formula (5):

[0054]

[0055] In the formula:

[0056] η—oil displacement efficiency, expressed as a percentage;

[0057] V o (t) — Cumulative oil production at time t, in cubic centimeters (cm³) 3 );

[0058] S wi —Bound water saturation, %;

[0059] V p —Effective pore volume of rock sample, cm 3 .

[0060] This invention relates to a physical simulation device and method for thermal flooding in ultra-deep, low-permeability heavy oil reservoirs, simulating the injection process of high-energy chemicals and their reaction within the reservoir. The invention automatically monitors and collects data on lateral and longitudinal temperature changes in the reservoir after the high-energy chemicals generate heat, as well as changes in reservoir pressure caused by gas production and the produced fluid. This allows for the study of reaction conditions of high-energy chemicals in different reservoirs, clarifying heat transfer patterns, the energy-enhancing properties of the generated products, and the variation in oil displacement efficiency. Furthermore, this invention simulates the injection method of high-energy chemicals into the reservoir and the exothermic and energy-enhancing reaction process within the reservoir, studying the reaction conditions of high-energy chemicals in different reservoirs, clarifying heat transfer patterns, the energy-enhancing properties of the generated products, and the variation in oil displacement efficiency. Attached Figure Description

[0061] Figure 1 This is a structural diagram of the physical simulation device for internalizing ultra-deep, low-permeability heavy oil reservoirs using student thermal flooding, as described in this invention.

[0062] Figure 2 This is a flowchart of a specific embodiment of the indoor physical simulation method for student thermal flooding in ultra-deep heavy oil reservoirs according to the present invention;

[0063] Figure 3 This is a schematic diagram of the longitudinal temperature sensor distribution in core 2 according to a specific embodiment of the present invention;

[0064] Figure 4 This is a diagram showing the temperature changes during an experiment in a specific embodiment of the present invention;

[0065] Figure 5 This is a diagram showing the pressure changes during an experiment in a specific embodiment of the present invention;

[0066] Figure 6 This is a graph showing the change in oil displacement efficiency after blowout in a specific embodiment of the present invention;

[0067] Figure 1: High-precision injection pump; Figure 2: Intermediate container for chemical filling.

[0068] 3: Back pressure valve; 4: Confining pressure tracking pump

[0069] 5: Pressure sensor; 6, 7, 8, 9, 10: Sealing cap

[0070] 11, 12, 13, 14, 15, 16, 17: Temperature sensors

[0071] 18: Data Acquisition System 19: Core 1

[0072] 20: Core clamping device; 21: Core 2

[0073] 22: High-pressure vessel; 23, 24, 25, 26: Valves. Detailed Implementation

[0074] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0075] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments of the present invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, and / or combinations thereof.

[0076] The physical simulation device for internal chemical thermal flooding of ultra-deep, low-permeability heavy oil reservoirs consists of a reservoir multi-directional temperature and pressure simulation system, a bi-component high-energy chemical agent reaction simulation system, an outlet backpressure tracking and control system, a chemical agent injection system, and a data acquisition system.

[0077] The chemical injection system simulates the process of injecting chemicals from the wellhead and is connected to the inlet outside the high-pressure vessel.

[0078] The bicomponent high-energy chemical agent reaction simulation system simulates the reaction process of bicomponent chemical agents in the near-wellbore zone. It is located at the inlet end inside the high-pressure container and is in contact with the large core of the reservoir multi-directional temperature and pressure simulation system, which facilitates the transfer of reaction heat to the large core of the reservoir multi-directional temperature and pressure simulation system.

[0079] The reservoir multi-directional temperature and pressure simulation system simulates the temperature and pressure transmission patterns at different locations deep within the reservoir.

[0080] The outlet backpressure tracking control system is connected to the outside of the high-pressure vessel outlet end to control the outflow rate of the produced fluid and prevent the produced fluid from blowout.

[0081] The data acquisition system collects temperature and pressure changes during the experiment, connects temperature sensors and pressure gauges, and is located outside of other systems but centrally hosted on a computer.

[0082] The following are several specific embodiments of the application of the present invention.

[0083] Example 1

[0084] In a specific embodiment 1 of the present invention, the chemical agent injection system includes a high-precision injection pump 1, a chemical agent filling intermediate container 2, and a digital pressure gauge. The high-precision injection pump 1 injects crude oil, high-energy chemical agent A, high-energy chemical agent B, and hot water sequentially into the small core 19 through valve 23, the chemical agent filling intermediate container 2, and valve 24.

[0085] The dual-component high-energy chemical agent reaction simulation system includes a small-sized core 19 with similar or identical reservoir properties, a core clamping device 20, and temperature sensors. The core clamping device 20 has an inner ceramic tube and an outer steel tube, used to hold the small-sized core 19. After the small core 19 is saturated with crude oil, chemical agent A is injected first, followed by chemical agent B, and finally hot water above 70°C. When the injected hot water raises the inlet temperature of the small core 19 to above 60°C, it triggers a reaction between high-energy chemical agents A and B within the core 19, releasing a large amount of heat and gas. Simultaneously, three temperature sensors 11-13 are placed inside the sealing cap 6-8 to collect temperature changes during the reaction process, simulating the initiation reaction process of the high-energy chemical agent in the near-wellbore zone. The collected temperature data is then transmitted to a computer.

[0086] The reservoir multi-directional temperature and pressure simulation system includes a large-size core (21), a high-pressure vessel (22), temperature sensors, and pressure sensors. The physical properties of the large-size core are the same as or similar to those of the oil reservoir. The large-size core has a diameter of 30 cm and a length greater than 30 cm. A cylindrical hole with a diameter of 2.52 cm and a depth of 5.0 cm is drilled at the center of the large-size core. Four temperature sensors (14-17) are installed inside the large-size core (21) using sealing nuts (9-10) to collect temperature changes at different locations in the reservoir, both horizontally and vertically, during the high-energy chemical reaction. The high-pressure vessel (22) is made of 32CrMn4 steel, meeting the requirements for temperature resistance above 300℃ and pressure resistance above 50 MPa, and is used to hold the large-size core undergoing the high-energy chemical reaction. A vent valve (25) is arranged on the side of the high-pressure vessel (22), and a high-pressure sensor (5) is arranged on the top. The temperature sensor's measurement range is 0-350℃. The pressure sensor's measurement range is 0-100 MPa. In the dual-component high-energy chemical agent reaction simulation system, the high heat released from the reaction in small core 19 is conducted to large core 21, raising the temperature at the inlet of large core 21 to over 200℃, triggering the self-reaction of high-energy chemical agent A within large core 21. Temperature and pressure data collected by temperature and pressure sensors are transmitted to a computer.

[0087] The outlet backpressure tracking control system includes a high-precision backpressure valve 3, a backpressure tracking pump 4, and valve 26. It prevents the pressure inside the high-pressure container 22 from rising too rapidly, which could cause the product to be ejected at high pressure from the backpressure valve, resulting in inaccurate product measurement and reducing the risk of burns. The tracking pressure of the backpressure tracking pump 4 is set 0.2 MPa higher than the internal pressure of the filling and holding container 22 detected by the pressure sensor 5. The tracking pressure of the backpressure tracking pump 4 is applied to the high-precision backpressure valve 3. Under the action of the tracking pressure, the reaction product flows smoothly out of the backpressure valve outlet.

[0088] The data acquisition system 18 includes a signal acquisition and conversion card, a computer, and temperature and pressure data acquisition software. The computer receives temperature and pressure data, detects the activation temperature of chemical agent A after the injection of chemical agent B, and records the temperature and pressure changes of chemical agent A in the near-wellbore zone (small core) and in the deep formation (large core). Based on the collected data, the computer calculates the amount of heat generated by the reaction of high-energy chemical agent A and the heat conduction velocity in the large core. Using large-scale numerical simulation software, the calculation is scaled up to the reservoir level to determine the heating radius of high-energy chemical agent A under different injection volumes.

[0089] Example 2

[0090] In a specific embodiment 2 of the present invention, the specific experimental steps include:

[0091] Step 1: Prepare a small core sample (2.5cm x 10.0cm), dry it, and measure its volume (V). t(1) and weigh m 0(1) ;

[0092] Step 2: Prepare two large core samples, each measuring 10.0cm x 30.0cm. Drill a hole at one end of the core sample with a diameter equal to the diameter of the core support device and a depth of 5.0cm. After drilling and drying, the core sample volume V t(2) and weigh m 0(2) ;

[0093] Step 3: After vacuuming small core 1 and large core 2, saturate them with simulated formation water and weigh them respectively (m). 1(1) and m 1(2) Calculate the pore volume and porosity. The formulas for calculating pore volume and porosity are:

[0094]

[0095]

[0096] Where: m0—mass of the dry rock sample, g;

[0097] m1—mass of the rock sample after saturation with experimental water, in grams;

[0098] ρ w —The density of the experimental water used to saturate the rock sample at the measured temperature, in g / cm³ 3 ;

[0099] V p —Effective pore volume of rock sample, cm 3 ;

[0100] V t —Total volume of rock sample, cm 3 ;

[0101] φ—Porosity of rock sample, %.

[0102] Step 4: Oil displacement to create bound water. Displace saturated simulated formation water in small core 1 and large core 2 with crude oil until no more water is emitted from the core outlet, thus achieving the bound water state. Record the water volumes Vw1 and Vw2 displaced by small core 1 and large core 2, and calculate the bound water saturation.

[0103] The bound water saturation is calculated according to formula (3):

[0104]

[0105] In the formula:

[0106] S wi —Bound water saturation, %;

[0107] V w —The volume of water displaced from the rock, in cm³ 3 .

[0108] Step 5: Place the small core 1 and the large core 2 into the connected simulation device and insert the temperature sensor;

[0109] Step 6: Inject high-energy chemical agent A using high-precision injection pump 1 at a rate of 0.5 PV; record the outlet liquid production and outlet oil production at different time intervals during the injection process.

[0110] Step 7, Set the outlet back pressure. Set the back pressure tracking pump 4 to track a pressure that is 0.2 MPa higher than the internal pressure of the filling and holding container 22 detected by the pressure sensor 5, and perform automatic tracking;

[0111] Step 8: Inject 0.1 PV of high-energy chemical agent B into small core 1 using high-precision injection pump 1, and record the temperature and pressure changes during the injection process;

[0112] Step 9: Simulate the near-wellbore zone oil displacement process. Inject 0.1 PV of high-temperature hot water into core sample 1 using high-precision injection pump 1. High-energy chemical agents A and B within the core sample begin a chemical reaction. Record the temperature, pressure, outlet fluid production rate, and outlet oil production rate at different time intervals during the injection process.

[0113] Step 10: Simulate the deep formation oil displacement process. After the high-energy chemical agent reacts in the small core 1, heat is transferred to the large core. Once the temperature at the inlet of the large core reaches 200℃, the high-energy chemical agent A in the large core reacts spontaneously and continuously propagates towards the outlet. High-energy chemical agent A generates high heat, reducing the viscosity of the crude oil in the large core, while simultaneously generating a large amount of gas to displace the crude oil. Record the temperature, pressure, outlet liquid production, and outlet oil production (Vo(t)) at different time intervals during the reaction process.

[0114] Step 11: After the pressure and temperature are balanced, release the outlet back pressure and record the final liquid production and oil production (Vo(t)) to calculate the oil displacement efficiency.

[0115] Oil displacement efficiency is calculated according to formula (5):

[0116]

[0117] In the formula:

[0118] η—oil displacement efficiency, expressed as a percentage;

[0119] V o (t) — Cumulative oil production at time t, in cubic centimeters (cm³) 3 )

[0120] Example 3

[0121] In a specific embodiment 3 of the present invention, the invention is applied. Figure 2 This is a flowchart of a specific embodiment of the indoor physical simulation method for heavy oil reservoir internalization and thermal oil displacement according to the present invention.

[0122] Step 101: Obtain the physical properties of core 1, including core dimensions, core weight, and other parameters;

[0123] Step 102: Drill a hole at one end of core 2 as required, and obtain the physical property parameters of core 2 after drilling, including core specifications, core weight and other parameters.

[0124] Step 103: After vacuuming core 1 and core 2, saturate them with simulated formation water, weigh them, and obtain the pore volume and porosity of the cores.

[0125] Step 104: Core 1 and Core 2 are saturated with oil to obtain the original oil saturation and bound water saturation.

[0126] Step 105: Place the core sample into the experimental apparatus, according to... Figure 1 As shown, connect the experimental setup, insert the temperature sensors, tighten the sealing caps to ensure the device is airtight, and the longitudinal temperature sensors (14 and 15, 16 and 17) are distributed as follows. Figure 3 As shown, R is 5.0 cm and r is 2.5 cm;

[0127] Step 106: Open valves 23 and 24, and close valves 25 and 26. Inject high-energy chemical agent A using high-precision injection pump 1 at a rate of 0.5 PV; record the stage oil production and stage liquid production during the injection process.

[0128] Step 107: Set the back pressure tracking pump 4 to track a pressure that is 0.2 MPa higher than the internal pressure of the filling and holding container 22 detected by the pressure sensor 5, and perform automatic tracking;

[0129] Step 108: Use high-precision injection pump 1 to inject 0.1PV high-energy chemical agent B into core 1, and obtain the temperature, pressure, stage oil production and stage liquid production of core and container during the injection process;

[0130] Step 109: Use high-precision injection pump 1 to inject 0.1PV high-temperature hot water into core 1, and obtain the temperature, pressure and stage oil production of core and container during the injection process.

[0131] Step 110: After stopping the injection, continue to record the temperature, pressure, outlet liquid output, and outlet oil output at different time intervals during the reaction process.

[0132] Step 111: After the pressure and temperature are balanced, release the outlet back pressure, record the final oil production (Vo(t)) and liquid production, and calculate the oil displacement efficiency.

[0133] Example 4

[0134] In a specific embodiment 4 of the present invention, the indoor physical simulation method for heavy oil reservoir internalization of student thermal flooding includes:

[0135] Step 1: Prepare core sample 1, 2.5 cm in diameter and 10.0 cm in length. After drying, the gas permeability is measured to be 127.8 × 10⁻⁶. -3 μm 2 It weighs 101.60g;

[0136] Step 2: Prepare core 2, 10.0 cm in diameter and 30.0 cm in length. After drying, the gas permeability is measured to be 145.7 × 10⁻⁶. -3 μm 2 A hole with a diameter of 4.5 cm and a depth of 5.0 cm was drilled at one end of the core sample. The weight after drilling was 4713.80 g.

[0137] Step 3: Vacuum core 1 and saturate it with distilled water (density 1.000 g / cm³). 3 The core sample weighed 111.65g and had a porosity of 20.5%. Core 2 was vacuum-sealed with saturated distilled water (density 1.000g / cm³). 3 The weight is 5187.13g, and the calculated porosity is 20.3%.

[0138] Step 4: Saturate core 1 with oil, injecting a total of 7.8 cm of crude oil. 3 The original oil saturation was calculated to be 77.61%, and the bound water saturation was 22.39%. A total of 247.9 cm³ of oil was injected from core 2 to saturate it. 3 The original oil saturation was calculated to be 52.37%, and the bound water saturation was 47.63%.

[0139] Step 5: Place the saturated core samples 1 and 2 into the experimental apparatus, and proceed according to... Figure 1 Connect the experimental setup; insert the temperature sensor and tighten the sealing nut;

[0140] Step 6: Open valves 23 and 24, close valves 25 and 26, and inject 1.7 ml of high-energy chemical agent A24 into core 1 at a rate of 2.0 ml / min. Record the temperature, pressure, outlet liquid production, and outlet oil production at different time intervals during the injection process.

[0141] Step 7: Set the back pressure tracking pump 4 to track a pressure that is 0.2 MPa higher than the internal pressure of the filling and holding container 22 detected by the pressure sensor 5, and perform automatic tracking;

[0142] Step 8: Add 48.3 ml of high-energy chemical agent B to core 1 at a rate of 2.0 ml / min, and record the temperature, pressure, outlet liquid production, and outlet oil production at different time intervals during the injection process.

[0143] Step 9: Inject 48.3 ml of 82℃ hot water into core 1 at a rate of 2.0 ml / min, and record the temperature, pressure, outlet liquid production, and outlet oil production at different time intervals during the injection process;

[0144] Step 10: Stop the injection and continue to record the temperature, pressure, outlet liquid output, and outlet oil output at different time intervals during the reaction process;

[0145] Step 11: After the pressure and temperature are balanced, release the outlet back pressure, record the final oil production and liquid production, and calculate the oil displacement efficiency.

[0146] Temperature changes during the experiment are as follows Figure 4 As shown, the pressure changes are as follows: Figure 5 As shown, the change in oil displacement efficiency is as follows: Figure 6 As shown.

[0147] Finally, it should be noted that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

[0148] Except for the technical features described in the specification, all other technologies are known to those skilled in the art.

Claims

1. A physical simulation device for thermal flooding of ultra-deep, low-permeability heavy oil reservoirs, characterized in that: The physical simulation device for thermal flooding of ultra-deep, low-permeability heavy oil reservoirs includes a multi-directional temperature and pressure simulation system, a bicomponent high-energy chemical agent reaction simulation system, a chemical agent injection system, and a data acquisition system. The multi-directional temperature and pressure simulation system has a high-pressure container to simulate the temperature and pressure conduction patterns at different locations in the deep reservoir. The chemical agent injection system is connected to the inlet outside the high-pressure container to simulate the injection process of the chemical agent from the wellhead. The bicomponent high-energy chemical agent reaction simulation system is located at the inlet inside the high-pressure container to simulate the reaction process of the bicomponent chemical agent in the near-wellbore zone. The data acquisition system is connected to the multi-directional temperature and pressure simulation system and the bicomponent high-energy chemical agent reaction simulation system to collect temperature and pressure changes during the experiment and transmit the collected data to an external computer. The dual-component high-energy chemical agent reaction simulation system includes a small-sized core with similar or identical reservoir properties and a core clamping device. The core clamping device is used to hold the small-sized core. After the small-sized core is saturated with crude oil, chemical agent A is injected first, followed by chemical agent B, and finally hot water above 70°C is injected. When the injected hot water raises the temperature at the inlet end of the small-sized core to above 60°C, it triggers the reaction between chemical agent A and chemical agent B in the small-sized core, releasing a large amount of heat and gas, simulating the initiation reaction process of high-energy chemical agents in the near-wellbore zone. The bicomponent high-energy chemical agent reaction simulation system comes into contact with the large-size core of the reservoir multi-directional temperature and pressure simulation system, which facilitates the transfer of reaction heat to the large-size core of the reservoir multi-directional temperature and pressure simulation system.

2. The physical simulation device for internal thermal flooding of ultra-deep, low-permeability heavy oil reservoirs according to claim 1, characterized in that, The physical simulation device for thermal flooding of ultra-deep, low-permeability heavy oil reservoirs also includes an outlet backpressure tracking control system. This system is connected to the outside of the outlet end of the high-pressure vessel to control the outflow rate of the produced fluid and prevent blowouts.

3. The physical simulation device for thermal flooding of ultra-deep, low-permeability heavy oil reservoirs according to claim 2, characterized in that, The outlet backpressure tracking control system includes a high-precision backpressure valve and a backpressure tracking pump. The high-precision backpressure valve is connected to the outside of the outlet end of the high-pressure vessel and to the backpressure tracking pump. The backpressure tracking pump is connected to the data acquisition system. The tracking pressure of the backpressure tracking pump is set to be 0.2 MPa higher than the internal pressure of the high-pressure vessel detected by the data acquisition system. The tracking pressure of the backpressure tracking pump is applied to the high-precision backpressure valve. Under the action of the tracking pressure, the reaction products flow out smoothly from the outlet of the high-precision backpressure valve.

4. The physical simulation device for internal thermal flooding of ultra-deep, low-permeability heavy oil reservoirs according to claim 1, characterized in that, The chemical agent injection system includes a high-precision injection pump and a chemical agent filling intermediate container. The high-precision injection pump is connected to the chemical agent filling intermediate container, which is connected to the bicomponent high-energy chemical agent reaction simulation system. The high-precision injection pump sequentially injects crude oil, chemical agent A, chemical agent B, and hot water into the bicomponent high-energy chemical agent reaction simulation system through the chemical agent filling intermediate container.

5. The physical simulation device for internal thermal flooding of ultra-deep, low-permeability heavy oil reservoirs according to claim 1, characterized in that, The core clamping device has an inner ceramic tube and an outer steel tube.

6. The physical simulation device for internal thermal flooding of ultra-deep, low-permeability heavy oil reservoirs according to claim 1, characterized in that, The reservoir multi-directional temperature and pressure simulation system includes the large-size core and the high-pressure container. The high-pressure container is used to hold the large-size core. The high heat released by the reaction in the binary high-energy chemical agent reaction simulation system is conducted to the large-size core, causing the temperature at the inlet end of the large-size core to rise to over 200°C, triggering the reaction of chemical agent A transmitted to the large-size core by the binary high-energy chemical agent reaction simulation system.

7. The physical simulation device for internal thermal flooding of ultra-deep, low-permeability heavy oil reservoirs according to claim 6, characterized in that, The high-pressure vessel is made of 32CrMn4 steel, which meets the requirements for temperature resistance above 300℃ and pressure resistance above 50MPa.

8. The physical simulation device for internal thermal flooding of ultra-deep, low-permeability heavy oil reservoirs according to claim 6, characterized in that, The large core has a diameter of 30cm and a length greater than 30cm; a cylindrical hole with a diameter of 2.52cm and a depth of 5.0cm is drilled at the center of the large core.

9. The physical simulation device for thermal flooding of ultra-deep, low-permeability heavy oil reservoirs according to claim 6, characterized in that, The data acquisition system includes multiple small-sized core temperature sensors, multiple large-sized core temperature sensors, and a pressure sensor. The multiple small-sized core temperature sensors are connected to the small-sized core and collect temperature changes during the reaction process of the small-sized core, transmitting the collected temperature data to an external computer. The pressure sensor is located at the top of the high-pressure vessel. The multiple large-sized core temperature sensors are connected to the large-sized core and collect temperature changes at different locations in the reservoir, both laterally and longitudinally, during the reaction of chemical agent A in the large-sized core, transmitting the temperature data to an external computer. The pressure sensor collects pressure data within the high-pressure vessel and transmits the pressure data to an external computer.

10. The physical simulation device for internal thermal flooding of ultra-deep, low-permeability heavy oil reservoirs according to claim 9, characterized in that, After receiving temperature and pressure data, the external computer detects the starting temperature of chemical agent A after the injection of chemical agent B; it records the temperature and pressure changes of chemical agent A in the near-wellbore zone (i.e., the small-sized core) and the temperature and pressure changes of chemical agent A in the deep formation (i.e., the large-sized core); based on the collected data, the computer calculates the amount of heat generated by the reaction of chemical agent A and the heat conduction speed in the large-sized core, and scales it up proportionally to the reservoir to calculate the heating radius of chemical agent A in the reservoir under different injection volumes.

11. A physical simulation method for internalized thermal flooding of ultra-deep, low-permeability heavy oil reservoirs, characterized in that... The method for internalizing the student thermal flooding physical simulation of ultra-deep, low-permeability heavy oil reservoirs uses the student thermal flooding physical simulation device described in claim 1, comprising: Step 1, prepare small size core, after drying, measure the core volume V t-1 and weigh m 0-1 ; Step 2: Prepare a large-size core. Drill a hole at one end of the large-size core with a diameter equal to the diameter of the core clamping device in the bicomponent high-energy chemical agent reaction simulation system, and a depth of 5.0 cm. After drilling and drying, the core volume V t-2 and weigh m 0-2 ; Step 3: Vacuum-saturate small and large core samples with simulated formation water, and weigh them separately (m). 1-1 and m 1-2 Calculate pore volume and porosity; Step 4: Oil-driven water displacement to create bound water; Step 5: Place the small and large cores into the thermal flooding physical simulation device for ultra-deep, low-permeability heavy oil reservoirs and insert temperature sensors. Step 6: Inject chemical agent A using the chemical agent injection system at a rate of 0.5 PV; record the outlet liquid production rate and outlet oil production rate at different time intervals during the injection process. Step 7, set the outlet back pressure; Step 8: Inject 0.1 PV of chemical agent B into a small core using the chemical agent injection system, and record the temperature and pressure changes during the injection process; Step 9: Simulate the near-wellbore zone oil displacement process; Step 10: Simulate the deep oil displacement process in the formation; Step 11: After the pressure and temperature are balanced, release the outlet back pressure, record the final liquid production and oil production, and calculate the oil displacement efficiency.

12. The method for physical simulation of student thermal flooding in ultra-deep, low-permeability heavy oil reservoirs according to claim 11, characterized in that, In step 3, the formulas for calculating pore volume and porosity are as follows: （1） （2） In the formula: —Mass of dry rock sample, g; —The mass of the rock sample after saturation with experimental water, in grams; —The density of the experimental water used to saturate the rock sample at the measured temperature, in g / cm³ 3 ; —Effective pore volume of rock sample, cm 3 ; —Total volume of rock sample, cm 3 ; —Porosity of rock sample, %.

13. The method for internalizing student thermal flooding physical simulation of ultra-deep, low-permeability heavy oil reservoirs according to claim 11, characterized in that, In step 4, crude oil is used to displace small and large core samples saturated with formation water until no more water is emitted from the core outlet, thus reaching the bound water state. The water volumes Vw1 and Vw2 displaced by the small and large core samples are recorded, and the bound water saturation is calculated.

14. The method for internalizing student thermal flooding physical simulation of ultra-deep, low-permeability heavy oil reservoirs according to claim 13, characterized in that, In step 4, the bound water saturation is calculated according to equation (3): （3） In the formula: —Bound water saturation, %; —Effective pore volume of rock sample, cm 3 ; —The volume of water displaced from the rock, in cm³ 3 .

15. The method for internalizing student thermal flooding physical simulation of ultra-deep, low-permeability heavy oil reservoirs according to claim 11, characterized in that, In step 7, the back pressure tracking pump of the outlet back pressure tracking control system is set to track a pressure 0.2 MPa higher than the pressure inside the high-pressure vessel in the reservoir multi-directional temperature and pressure simulation system detected by the pressure sensor in the data acquisition system, and automatic tracking is performed.

16. The method for internalizing student thermal flooding physical simulation of ultra-deep, low-permeability heavy oil reservoirs according to claim 11, characterized in that, In step 9, 0.1 PV of high-temperature hot water is injected into the small core using a chemical injection system, and high-energy chemical agents A and B in the small core begin to react chemically; the temperature, pressure, outlet liquid production, and outlet oil production are recorded at different time intervals during the injection process.

17. The method for internalizing student thermal flooding physical simulation of ultra-deep, low-permeability heavy oil reservoirs according to claim 11, characterized in that, In step 10, the heat from the reaction of the high-energy chemical agent in the small core is transferred to the large core. After the temperature at the inlet end of the large core reaches 200°C, the chemical agent A in the large core reacts spontaneously and continues to move towards the outlet end. The chemical agent A generates high heat to reduce the viscosity of crude oil in the large core, and at the same time generates a large amount of gas to displace the crude oil. The temperature, pressure, outlet liquid production, and outlet oil production are recorded at different time intervals during the reaction process.

18. The method for internalizing student thermal flooding physical simulation of ultra-deep, low-permeability heavy oil reservoirs according to claim 11, characterized in that, In step 11, the oil displacement efficiency is calculated according to formula (5): （4） In the formula: —Oil displacement efficiency, expressed as a percentage; —Cumulative oil production at time t, in cubic centimeters (cm³) 3 ); —Bound water saturation, %; —Effective pore volume of rock sample, cm³ 3 .

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