Oil reservoir microbial flooding three-dimensional physical simulation experiment device and experiment method

Abstract

The invention provides an oil reservoir microbial flooding three-dimensional physical simulation experiment device and an experiment method. The experiment device comprises an injection unit, a model unit, an extraction metering unit, a data acquisition and processing unit and a control unit, the injection unit comprises an injection pump, an intermediate container, a pressurizing device and a liquid supplementing device, the model unit comprises a model pressure cabin and an annular pressure device, an outcrop core is arranged in the model pressure cabin to serve as a three-dimensional physical model, point locations are screened on the outcrop core for drilling, and a sensor and a probe are arranged on the outcrop core; and the extraction metering unit comprises a separation device, a metering device and a pressure return device. According to the invention, a three-dimensional physical simulation experiment aiming at microbial displacement is designed, a model pressure chamber and a rock core model are taken as main bodies, oil reservoir physical characteristics and microbial growth conditions are simulated through real-time detection and control, the microbial oil displacement effect is evaluated, microbial growth and metabolism characteristics, seepage rules and oil displacement mechanism researches are deeply carried out, and the oil displacement effect is evaluated. And guidance is provided for the actual oil reservoir oil extraction process.

Description

Technical Field

[0001] This invention belongs to the field of reservoir development and exploration technology, and relates to a three-dimensional physical simulation experimental device and method for reservoir microbial flooding. Background Technology

[0002] Petroleum, as the "lifeblood of industry," is one of the world's most important non-renewable resources. Its extraction and utilization are fundamental to modern industrial society, and improving oil recovery rates is a continuous pursuit. After primary oil recovery (utilizing natural energy) and secondary oil recovery (water injection), a large amount of crude oil remains in the formation, necessitating tertiary oil recovery, a crucial technology for improving oil recovery rates. Microbial flooding (MFGF) is a low-cost, environmentally friendly tertiary oil recovery technology. It involves injecting microorganisms, nutrients, or metabolic products into the underground oil reservoir. The method utilizes the microbial cells or their metabolic gaseous products, surfactants, organic acids, polymers, and other substances to enhance oil recovery rates. Compared to other tertiary oil recovery technologies, MFGF has a wide range of applications and simple processes, showing promising prospects and thus attracting increasing attention.

[0003] Microbial enhanced oil recovery (MEOR) involves the growth and metabolism of microorganisms in oil reservoirs. It is a complex process that can improve oil washing efficiency, expand swept volume, and generate gas to increase pressure, encompassing almost all mechanisms for enhancing oil recovery. Physical simulation is an important approach to understanding reservoir development processes and studying fluid flow patterns. Therefore, physical simulation of microbial displacement is a crucial tool for understanding the characteristics of microbial displacement reservoir development, clarifying the growth, metabolism, and seepage capacity of microorganisms in the reservoir, and understanding the residual oil occurrence patterns during microbial displacement. Based on different physical simulation scales, it can be divided into micropore simulation, one-dimensional linear simulation, two-dimensional planar simulation, and three-dimensional simulation. Among them, three-dimensional physical simulation has a larger scale and can clearly describe the multiphase flow changes of microorganisms, products, and residual oil during microbial displacement, making it an important research method for physical simulation of MEOR.

[0004] CN 115450607A discloses a three-dimensional physical simulation experimental device and method for complex fractured-vuggy reservoirs. The device includes a fluid injection system, a reservoir simulation system, and an experimental recording system. The reservoir simulation system comprises an experimental chamber, insulating filters, fracture simulation devices, cavern simulation devices, a wellbore, and measuring electrodes. The inner wall of the chamber is equipped with an anti-channeling structure, and the intersections of the convex structures on the anti-channeling structure are frosted with a circular cross-section whose diameter is equal to the height of the convex structure. Two layers of detachable insulating filters are installed equidistantly inside the chamber. The fracture simulation devices and cavern simulation devices are fixedly installed inside the chamber using fracture and cavern fixing components. This device is designed for three-dimensional simulation of reservoirs with complex fractured-vuggy structures, but it still uses traditional gas-drive and water-drive methods for physical simulation. It targets different stages of the oil production process and does not involve microbial displacement systems; therefore, it does not include unit structures matching microbial displacement systems.

[0005] CN 107100602A discloses an automatic vacuuming and saturation device for a three-dimensional scale model used in microbial enhanced oil recovery. The device includes a vacuuming unit, a formation water saturation unit, and a control unit. The control unit comprises a vacuuming control device, a formation water saturation control device, and an overpressure protection device. The vacuuming control device controls the vacuuming unit to automatically vacuum the model, the formation water saturation control device controls the formation water saturation unit to automatically saturate the model with formation water, and the overpressure protection device controls the pressure of the three-dimensional scale model when formation water is saturated. Although this device involves microbial enhanced oil recovery, it only specifies the structural units for vacuuming and saturating water; it does not disclose the reservoir model structure, the microbial enhanced oil recovery operation process, or the indicators and characteristics to be detected.

[0006] CN 204152493U discloses an injection device for a physical simulation experiment of microbial enhanced oil recovery. This device includes an injection power section, an injection container section, a model body section, a metering and detection section, and a control section. The injection container section consists of an intermediate container body, a support, an insulation layer, and a temperature control device. The intermediate container body is placed inside the insulation layer, and the intermediate container body and insulation layer are mounted on the support. The metering and detection section consists of a gas collection device, an oil-gas-water separator, a crude oil collection device, and a produced water collection device. The oil-gas-water separator is connected to the outlet of the model pipe. The gas collection device is installed at the top of the oil-gas-water separator, and the produced water collection device is installed at the bottom of the oil-gas-water separator. This simulation experiment device focuses on the structure of the injection and metering and detection sections. However, only one injection container is provided, making it difficult to separately inject gases and multiple liquids. Furthermore, the structure of the model body section is not described in detail, and the operational process during microbial displacement and the parameters that need to be monitored are not addressed.

[0007] In summary, for experimental devices and methods of three-dimensional physical simulation using microbial flooding, it is necessary to design experimental devices that meet the requirements of multi-media injection and displacement based on the structural characteristics of the model, and to clarify the displacement process in order to evaluate the microbial growth and oil displacement effect, and provide guidance for actual reservoir development. Summary of the Invention

[0008] To address the problems existing in the prior art, the present invention aims to provide a three-dimensional physical simulation experimental device and method for microbial flooding in oil reservoirs. The device, through the setting of a model pressure chamber and a core model in the model unit, and equipped with an injection unit and a production metering unit, constitutes a displacement process unit to simulate the physical characteristics of oil reservoirs and the growth conditions of microorganisms, realize three-dimensional physical simulation of microbial flooding, evaluate the effect of microbial oil displacement, conduct in-depth research on the oil displacement mechanism, and provide guidance for the actual oil production process in oil reservoirs.

[0009] To achieve this objective, the present invention adopts the following technical solution:

[0010] This invention provides a three-dimensional physical simulation experimental device for reservoir microbial flooding. The experimental device includes an injection unit, a model unit, a production metering unit, a data acquisition and processing unit, and a control unit. The injection unit, model unit, and production metering unit are connected in sequence. The data acquisition and processing unit is connected to both the model unit and the production metering unit. The control unit is connected to all other units.

[0011] The injection unit includes an injection pump, an intermediate container, a pressurization device, and a liquid replenishment device. The intermediate container includes a gas container group and a liquid container group. The model unit includes a model pressure chamber and a ring pressure device. The intermediate container and the pressurization device are both connected to the model pressure chamber. The liquid replenishment device is connected to both the intermediate container and the model pressure chamber. An outcrop core is set in the model pressure chamber as a three-dimensional physical model. Points are drilled on the outcrop core to form a pore structure, and sensors and probes are arranged according to the injection and production method. The production metering unit includes a separation device, a metering device, and a backpressure device. The data acquisition and processing unit includes sensors and data processing software.

[0012] In this invention, a three-dimensional physical simulation of the tertiary oil recovery process in an oil reservoir is performed using microbial flooding. The model uses a pressure chamber and outcrop core as the main components, and is further equipped with an injection unit and a production metering unit to form a displacement process unit. Real-time monitoring and control are achieved through data acquisition and processing units and a control unit. This simulates the reservoir's physical properties and microbial growth conditions. Rapid tracking and detection of pressure, resistivity, and biochemical indicators are used to evaluate the microbial flooding effect and saturation changes. In-depth research is conducted on the microbial growth and metabolic characteristics, seepage patterns, and oil displacement mechanisms. The microbial flooding well network and supporting processes are optimized, providing guidance for actual oil reservoir production processes. The device has a reasonable structural design, a high degree of automation, and a wide range of applications.

[0013] The following are preferred technical solutions of the present invention, but are not intended to limit the technical solutions provided by the present invention. The technical objectives and beneficial effects of the present invention can be better achieved and realized through the following technical solutions.

[0014] As a preferred technical solution of the present invention, the injection pump is a dual-cylinder pump, and the number of such pumps includes at least two, such as two, three or four.

[0015] In this invention, the injection pump can be a dual-cylinder constant speed and constant pressure pump. Each cylinder has an independent cylinder transmission mechanism, pressure detector, flow controller, DC servo motor and servo control system. The pump body delivers and draws fluid through software control. When one cylinder of the dual-cylinder pump is used to deliver fluid, the other cylinder will quickly draw it in and pre-pressurize it by tracking the operating pressure. This makes the fluid flow continuous and pulse-free when the pump body alternates. The injection pump provides a power source for the experiment and can operate continuously without pulses, at constant speed and constant pressure.

[0016] Preferably, the intermediate containers are all installed in a temperature control component, which includes a constant temperature chamber.

[0017] In this invention, the temperature control component is a hot air circulating thermostatic chamber, which functions to provide the required constant temperature environment for intermediate containers and the like outside the model unit.

[0018] Preferably, the liquid container group includes a water container group, an oil container group, and a nutrient solution container group.

[0019] Preferably, the gas container group and each liquid container group are arranged in groups, with at least two of each, such as two, three or four.

[0020] In this invention, the intermediate container provides the displacing fluid for the experiment and stores gas, water, oil, and microbial nutrient solution respectively. The gas container is equipped with a piston rod and displacement sensor, which can measure the gas volume under high pressure. The intermediate container is installed in a constant temperature chamber for easy installation and operation. The maximum working pressure is 32 MPa and the maximum working temperature is 80°C.

[0021] Preferably, the liquid replenishment device includes a water replenishment container and an oil replenishment container.

[0022] In this invention, the fluid replenishment device is mainly used for rapid fluid replenishment of container groups and pre-filling of fluid in the annular space of the core holder. It can also be used for cleaning and emptying process pipelines and intermediate containers.

[0023] Preferably, the pressurization device includes a pressurization pump, a pressurization container, and a pressure regulator connected in sequence, and the outlet of the pressure regulator is connected to the connecting pipeline between the gas container group and the model pressure chamber.

[0024] In this invention, the booster pump pressurizes the gas medium into the booster container, the output pressure can be adjusted by setting a pressure regulator, and a pressure gauge is set to detect the pressure.

[0025] In this invention, high-pressure pipe valves are used in the process pipeline of the injection unit, such as stainless steel pipe valves. The maximum working pressure of the valves and pipe connectors is 50 MPa, and the maximum working temperature does not exceed 180°C. The inlet end of the model pressure chamber is equipped with a high-pressure sensor and a low-pressure sensor, and is also equipped with a low-pressure protection shut-off valve.

[0026] As a preferred technical solution of the present invention, the model pressure chamber is a model holder with a circular steel structure, a top cover, and fluid inlet and outlet and parameter test port on the side wall.

[0027] In this invention, based on the structure of the model unit, different injection and production methods are studied according to experimental requirements. This enables the loading of the model and the application of overburden pressure to the model, simulating the working environment temperature, and ensuring the safety of the model. The model pressure chamber is connected to the external power unit, metering and analysis unit, and other units through data wires, fluid pipelines, and temperature and pressure sensors. It is under the unified management and control of the central control platform and is used to simulate the physical properties of the reservoir, such as temperature, pressure, and porous media, as well as the growth and metabolism conditions of microorganisms, such as electron acceptors. This enables three-dimensional physical simulation of microbial flooding. Combined with rapid tracking and detection of pressure, resistivity, and biochemical indicators, the effect of microbial flooding and changes in saturation are evaluated.

[0028] Preferably, the side wall of the model pressure chamber is also provided with annular pressure fluid control port and back pressure fluid control port.

[0029] Preferably, the size of the physical model of the outcrop core does not exceed 500×500×500mm, such as 500×500×500mm, 450×450×300mm, 400×400×100mm, 300×300×200mm, 200×200×50mm or 100×100×30mm, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable, and the model is encapsulated with epoxy resin.

[0030] In this invention, the model pressure chamber is a large clamp with a high-pressure resistant circular cylinder structure. The upper part has a top cover, and the side walls are equipped with fluid inlets and outlets, as well as control ports for annular and back pressure fluids, and test ports for signal parameters such as pressure, temperature, and resistance. The fluid inlet and outlet are equipped with high-pressure valves, which can inject and discharge experimental media into the high-pressure chamber. The three-dimensional physical model used is a block-shaped reservoir outcrop, which is wrapped with epoxy resin. Electrodes are arranged on the top and bottom of the physical model to measure parameters such as resistance and oil saturation distribution, and pressure measurement probes are arranged to obtain pressure data.

[0031] Preferably, at the selected locations on the outcrop, 2 to 8 cylindrical core samples are drilled, such as 2, 3, 4, 5, 6, 7, or 8. The size of the core samples is φ(2-3)×(2-10)cm, such as φ2×2cm, φ2.5×3cm, φ3×4cm, φ2×5cm, φ2.5×6cm, φ3×7cm, φ2×8cm, φ2.5×9cm, or φ3×10cm, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0032] Preferably, pressure sensors and saturation probes are deployed on the outcrop core physical model, and the injection and production method adopted is the one-injection-four-production method in the five-point injection and production method of oilfields.

[0033] In this invention, the detection of the physical model saturation is used to measure the resistivity within the model and further calibrate the oil saturation. By arranging an electrode matrix throughout the entire model area, the distribution of saturation within the model can be measured. By deploying oil saturation sensors at different locations to collect data, the test results can be displayed through a "cloud map" or "graphic".

[0034] Preferably, the model pressure chamber is further provided with an accessory structure, which includes a flat-cover electric moving structure, a safety valve, and an external coating insulation layer.

[0035] In this invention, the additional structure of the model pressure chamber includes a flat cover electric moving mechanism composed of a drive motor, a speed reduction gearbox, a ball screw, a support base, a slider, and a moving guide rail. The model pressure chamber is patched with a coating insulation layer, while the inner wall is prone to oxidation and rust due to prolonged high temperatures, requiring anti-corrosion treatment.

[0036] Preferably, the ring pressure device includes a ring pressure tracking pump, which is a dual-cylinder structure.

[0037] In this invention, the ring pressure tracking pump can automatically track the ring pressure and maintain a pressure difference with the injection pressure, which can be controlled by the control unit.

[0038] As a preferred technical solution of the present invention, the separation device in the extraction metering unit includes a gas-liquid separator and an oil-water separator, and the metering device includes a gas flow meter, an oil metering pump and a water metering pump.

[0039] Preferably, the extraction metering unit further includes an interface sensor located at the oil-water separator.

[0040] In this invention, the extraction metering unit utilizes the principle of gravity component and dual-pipe balance, employs an oil-water interface sensor to detect and control the oil-water interface, and is equipped with a gas flow meter, an oil metering pump, and a water metering pump. A gas flow controller can also be installed on the gas pipeline. The above metering devices are connected to a computer, and the computer collects and processes the data to obtain the real-time oil production, water production, and gas production. The oil production metering accuracy is 0.1 mL, the water production metering accuracy is 0.05 mL, and the gas production metering accuracy is 0.5 mL.

[0041] Preferably, the backpressure device includes a backpressure valve and a backpressure tracking pump, wherein the backpressure valve is located at the outlet section of the model pressure chamber, and the backpressure tracking pump is connected to the backpressure valve.

[0042] In this invention, the back pressure device is used to apply back pressure at the outlet end of the model pressure chamber. A back pressure valve is installed at the outlet section, and an automatic back pressure tracking pump is used to pre-load the back pressure valve. The material of the back pressure tracking pump can be stainless steel.

[0043] Preferably, the sensors in the data acquisition and processing unit include a temperature sensor, a pressure sensor, and a saturation sensor.

[0044] In this invention, the data acquisition is mainly accomplished by various sensors, including the detection of pressure, temperature, and saturation. Through signal transmission, the relevant data information is stored in multiple formats. The data processing software on the computer analyzes and processes the data according to user requirements, and can print raw data and processed data files, and draw relevant charts and curves of experimental results in real time.

[0045] As a preferred technical solution of the present invention, the experimental device further includes an auxiliary unit, which includes a vacuum pumping device and a wire cutting device.

[0046] Preferably, the vacuuming device includes a vacuum pump and a vacuum buffer container, and the vacuuming device is connected to the model pressure chamber and process pipelines.

[0047] Preferably, the vacuuming device is further equipped with a vacuum gauge and a dryer, the dryer being located between the vacuum pump and the vacuuming buffer container, and the vacuum gauge being located on the vacuuming pipeline.

[0048] In this invention, the vacuuming device is used for vacuuming process pipelines and consists of a vacuum pump, a vacuum buffer container, and a mobile support vehicle, and is equipped with a vacuum gauge and a triangular flask; the abrasive wire cutting device is an abrasive wire cutting machine, which is a special equipment for cutting various cylindrical and irregularly shaped rock samples in the laboratory.

[0049] In addition, other tools will be used in this invention, such as electric lifting tools for model cover plates and model installation; and miniature silent air compressors to provide low-pressure air sources for injection pumps and pneumatic valves in the process pipelines of the device, thereby realizing automated control of the equipment process.

[0050] On the other hand, the present invention provides an experimental method for conducting three-dimensional physical simulation of reservoir microbial flooding using the above-mentioned experimental apparatus, the experimental method comprising the following steps:

[0051] (1) Select outcrop rock cores as physical models. After drilling, laying and sealing, install them in the model pressure chamber, inject water and heat and pressurize them until the target value is reached.

[0052] (2) Turn on the injection pump and run the data acquisition and processing unit. First, replace the water with saturated oil to calculate the initial oil saturation. Then, perform one water drive and record the water drive recovery rate.

[0053] (3) After the first water flooding in step (2), microbial displacement is carried out. After the injection is completed, the microorganisms are cultured and then subjected to a second water flooding. The recovery rate of the second water flooding is recorded, and the data collected during the displacement process is processed.

[0054] (4) Turn off the injection pump, stop the operation of the data acquisition and processing unit, depressurize and drain the water before disassembling the model.

[0055] As a preferred technical solution of the present invention, in step (1), 2 to 8 cylindrical small cores are drilled from the selected points on the outcrop core, such as 2, 3, 4, 5, 6, 7 or 8 cores. The size of the small cores is φ(2 to 3) × (2 to 10) cm, such as φ2×2 cm, φ2.5×3 cm, φ3×4 cm, φ2×5 cm, φ2.5×6 cm, φ3×7 cm, φ2×8 cm, φ2.5×9 cm or φ3×10 cm, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0056] Preferably, the number of sensors deployed on the outcrop core in step (1) is 16 to 25, for example, 16, 18, 20, 22, 24 or 25, and the number of probes is 25 to 36, for example, 25, 27, 30, 32, 34 or 36.

[0057] Preferably, the encapsulation in step (1) is performed using epoxy resin.

[0058] Preferably, the encapsulated physical model described in step (1) is vacuumed and saturated with water to calculate the porosity and permeability of the core model.

[0059] In this invention, small core samples are drilled from outcrop core samples to make their pore structure approximate that of actual oil reservoirs, and the homogeneity of the core samples can be analyzed. After encapsulation, the core samples can be saturated with water after vacuuming. The porosity and permeability of the core samples can be calculated based on the amount of saturated water. The method of multi-point vacuuming and saturated water is used to ensure the vacuum level at different locations in the model. During vacuuming, all well positions are connected together and connected to the vacuum pump through multi-port valves, transparent hoses and special-shaped conversion joints, and two well positions at a certain distance from each other at the diagonal are reserved for connecting pressure sensors.

[0060] Preferably, the encapsulated physical model described in step (1) is installed in the model pressure chamber, the water source is connected to the water inlet of the chamber, the water inlet valve and the upper exhaust valve are opened when water is injected, and the exhaust valve indicates that the chamber is full of water after water comes out. Then the valves are closed.

[0061] In this invention, when the physical model is installed, the pressure well position and saturation probe on the model are connected to the pipelines and resistance wires on the pressure chamber cover in a certain order, and the valves of the unused pipelines are closed and marked; two sealing rings are made and installed on the side of the cover, the connection of the two sealing rings is placed separately, the foreign objects around the sealing rings are cleaned, and lubricating oil is applied to the sealing rings.

[0062] Clean the edges of the cabin, and properly position all pipes and resistor wires to ensure they do not interfere with cabin closure or touch the bottom of the cabin. Click the main power button and start button on the control panel. Click the cabin power button on the control panel screen, then click "Enter on" to observe the driving process. Once the model base contacts the cabin, click "Enter off" to remove the model base support. Click "Enter on" again. When there is approximately 5-6 cm between the hatch cover and the cabin, click "Enter off" to stop advancing. Install bolts on both sides of the front of the hatch cover, and tighten the bolts evenly to move the cabin forward until the hatch cover and cabin are tightly sealed. Click the clamp power button on the panel, then click "Close on." The clamps will automatically close and stop automatically when they reach the limit. Turn off the clamp power. The cabin closure is now complete. Remove the bolts on both sides of the front of the hatch cover and cover with the insulation layer.

[0063] When filling with water, open the water inlet valve at the rear of the compartment and the air vent valve on top of the compartment. At the same time, be sure to close the drain valve on the rear side of the compartment. Then start filling with water. When water comes out of the drain valve, the filling is finished. Then close the water inlet valve and the drain valve.

[0064] In this invention, during heating and pressurization, the "cabin heating power supply" and temperature control software on the control panel are turned on, and the heating temperature is set according to the procedure. When the temperature reaches the predetermined temperature, the pressure inside the cabin is monitored, and the ring pressure pump power is turned on. If the ring pressure has not yet reached the predetermined ring pressure, the ring pressure pump can be used to supplement the pressure. If the ring pressure rises to a higher pressure during the heating process, the pressure can be appropriately released through the exhaust valve until the pressure target value is reached. The temperature and pressure are set according to the experimental requirements.

[0065] As a preferred technical solution of the present invention, the displacement rate of water when the saturated oil displaces water in step (2) is 0.5 to 5 mL / min, for example, 0.5 mL / min, 1 mL / min, 1.5 mL / min, 2 mL / min, 2.5 mL / min, 3 mL / min, 3.5 mL / min, 4 mL / min, 4.5 mL / min or 5 mL / min, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable. The bound water is established by displacing water with oil, and the initial oil saturation is calculated.

[0066] In this invention, the temperature of the constant temperature chamber is set and the liquid in the intermediate container is preheated. When saturated oil is introduced, the valves on all saturated oil lines in the constant temperature chamber are opened, the injection and extraction ports are determined and opened, the injection speed of the injection pump is set, and the program of the extraction metering instrument is set according to the injection speed, so that displacement and sample collection can be carried out. When the displacement is completed, it can be observed whether there are any unsaturated points based on the collected saturation data, and the injection and extraction ports can be changed for supplementary displacement. When calculating the initial oil saturation, the amount of water displaced by the saturated oil is the amount of saturated oil entering. The initial oil saturation can be calculated by dividing the amount of saturated oil by the pore volume.

[0067] Preferably, the displacement rate during the first water flooding in step (2) is 0.5 to 5 mL / min, for example, 0.5 mL / min, 1 mL / min, 1.5 mL / min, 2 mL / min, 2.5 mL / min, 3 mL / min, 3.5 mL / min, 4 mL / min, 4.5 mL / min or 5 mL / min, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable. The displacement is carried out until the water content is 95 to 99%, for example, 95%, 95.5%, 96%, 96.5%, 97%, 97.5%, 98%, 98.5% or 99%, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0068] Preferably, the primary waterflood recovery rate in step (2) refers to the proportion of oil produced during a primary waterflood to the amount of saturated oil.

[0069] In this invention, during the first water flooding, all valves on the saturated oil lines in the constant temperature chamber are closed, all valves on the water flooding line are opened, the injection and production ports are identified and opened, the injection pump speed is set, and the production metering instrument program is set according to the injection speed to perform displacement and collect production samples. The water content can be calculated based on the water content in the produced fluid obtained from the production port, and the first water flooding recovery rate refers to the proportion of produced oil to saturated oil when the required water content is reached during the first water flooding. Subsequent microbial displacement and secondary water flooding only require switching all valves on the water flooding line and the injection system line; everything else is the same as the first water flooding.

[0070] As a preferred technical solution of the present invention, the microbial system is injected during the microbial displacement in step (3). The microbial system is in the form of microbial nutrient solution, wherein the microbial concentration is 4 to 6 wt%, such as 4 wt%, 4.5 wt%, 5 wt%, 5.5 wt%, or 6 wt%, etc., but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0071] Preferably, the types of microorganisms in the microbial system include Bacillus subtilis or Pseudomonas aeruginosa.

[0072] Preferably, the injection volume of the microbial system during microbial displacement in step (3) is 0.3 to 0.8 PV, such as 0.3 PV, 0.4 PV, 0.5 PV, 0.6 PV, 0.7 PV or 0.8 PV, but not limited to the listed values. Other unlisted values ​​within this range are also applicable. The injection rate is 0.5 to 5 mL / min, such as 0.5 mL / min, 1 mL / min, 1.5 mL / min, 2 mL / min, 2.5 mL / min, 3 mL / min, 3.5 mL / min, 4 mL / min, 4.5 mL / min or 5 mL / min, but not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0073] Preferably, during the microbial displacement in step (3), 0.1 to 0.5 PV of microbial system is injected, such as 0.1 PV, 0.2 PV, 0.3 PV, 0.4 PV or 0.5 PV, but not limited to the listed values. Other unlisted values ​​within this range are also applicable, and the microbial concentration is detected by sampling from different measurement points.

[0074] Preferably, after the microorganisms are injected in step (3), the culture period is 0 to 7 days, such as 0.1 days, 1 day, 2 days, 3 days, 4 days, 5 days, 6 days or 7 days, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0075] Preferably, the displacement rate during the secondary water flooding in step (3) is 0.5 to 5 mL / min, for example, 0.5 mL / min, 1 mL / min, 1.5 mL / min, 2 mL / min, 2.5 mL / min, 3 mL / min, 3.5 mL / min, 4 mL / min, 4.5 mL / min or 5 mL / min, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable. The displacement is carried out until the water content is 95 to 99%, for example, 95%, 95.5%, 96%, 96.5%, 97%, 97.5%, 98%, 98.5% or 99%, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0076] Preferably, in the secondary water drive process described in step (3), 0.1 to 0.5 PV of water is injected, such as 0.1 PV, 0.2 PV, 0.3 PV, 0.4 PV or 0.5 PV, but not limited to the listed values. Other unlisted values ​​within this range are also applicable. Samples are taken from different measurement points to detect the microbial concentration and surface tension.

[0077] As a preferred technical solution of the present invention, in step (4), the exhaust valve of the model pressure chamber is opened when depressurizing, and the water outlet valve is opened to drain the water after the pressure drops to normal pressure.

[0078] Preferably, after depressurization and drainage in step (4), the model pressure chamber is opened, the core model is disassembled, and subsequent model slicing is performed.

[0079] In this invention, after the displacement process is completed, the injection pump and data acquisition unit are turned off, the temperature control software is turned off to cool the chamber, the exhaust valve on the upper part of the chamber is opened to depressurize the chamber, and after the pressure drops to zero, the drain valve is opened to drain the chamber. Then, click the clamp power and open chamber on the control panel, the clamp begins to separate, after the clamp separation is completed, the clamp power is turned off, bolts are installed on the upper and lower parts of the front of the chamber cover, and the chamber is separated from the chamber cover by tightening the upper and lower bolts in a balanced manner until the motor can drive the chamber. Turn on the chamber power and reverse carriage on, observe the reverse carriage process, when the chamber is about to separate from the model base, click reverse carriage off, install the model base bracket, and then click reverse carriage on to continue reversing until it stops automatically. Turn off the chamber power, and finally disconnect the pressure well and saturation probe on the model from the instrument.

[0080] Compared with the prior art, the present invention has the following beneficial effects:

[0081] (1) This invention designs a three-dimensional physical simulation experimental device for microbial displacement, with a model pressure chamber and a core model as the main body, and is equipped with an injection unit and a production metering unit to form a displacement process unit. Combined with a data acquisition and processing unit and a control unit, it performs real-time detection and control, simulates reservoir physical properties and microbial growth conditions, and combines pressure, resistivity and biochemical indicators for rapid tracking and detection to evaluate the effect of microbial oil displacement, conduct in-depth research on microbial growth and metabolism characteristics, seepage laws and oil displacement mechanisms, optimize microbial well network and supporting process research, and provide guidance for actual reservoir oil production process;

[0082] (2) The device described in this invention has a reasonable structural design, a high degree of automation, and a wide range of applications. Attached Figure Description

[0083] Figure 1 This is a schematic diagram of the three-dimensional physical simulation experimental device for reservoir microbial flooding provided in Embodiment 1 of the present invention;

[0084] Figure 2 This is a simulated well network distribution diagram on the physical model of the outcrop core provided in Embodiment 1 of the present invention;

[0085] Among them, 1-injection pump, 21-gas container group, 22-oil container group, 23-water container group, 24-nutrient solution container group, 31-water replenishment container, 32-oil replenishment container, 41-boost pump, 42-boost container, 43-pressure regulator, 51-model pressure chamber, 52-outcrop core, 53-safety valve, 54-ring pressure tracking pump, 61-gas-liquid separator, 62-oil-water separator, 63-gas flow meter, 64-oil metering pump, 65-water metering pump, 66-back pressure valve, 67-back pressure tracking pump, 71-vacuum pump, 72-vacuum buffer container, 73-vacuum gauge, 74-dryer. Detailed Implementation

[0086] To better illustrate the present invention and facilitate understanding of its technical solutions, the present invention is further described in detail below. However, the following embodiments are merely simplified examples of the present invention and do not represent or limit the scope of protection of the present invention. The scope of protection of the present invention is determined by the claims.

[0087] The following are typical but non-limiting embodiments of the present invention:

[0088] Example 1:

[0089] This embodiment provides a three-dimensional physical simulation experimental device for reservoir microbial flooding. A schematic diagram of the experimental device is shown below. Figure 1 As shown, it includes an injection unit, a model unit, a production metering unit, a data acquisition and processing unit, and a control unit. The injection unit, model unit, and production metering unit are connected in sequence. The data acquisition and processing unit is connected to both the model unit and the production metering unit. The control unit is connected to all other units.

[0090] The injection unit includes an injection pump 1, an intermediate container, a pressurization device, and a liquid replenishment device. The intermediate container includes a gas container group 21 and a liquid container group. The model unit includes a model pressure chamber 51 and a ring pressure device. The intermediate container and the pressurization device are both connected to the model pressure chamber 51. The liquid replenishment device is connected to both the intermediate container and the model pressure chamber 51. An outcrop core 52 is set in the model pressure chamber 51 as a three-dimensional physical model. Points are drilled on the outcrop core 52 to form a pore structure, and sensors and probes are arranged according to the injection and production method. The production metering unit includes a separation device, a metering device, and a backpressure device. The data acquisition and processing unit includes sensors and data processing software.

[0091] The injection pump 1 is a dual-cylinder pump, and there are two of them.

[0092] The intermediate containers are all installed in a temperature control component, which is a constant temperature chamber.

[0093] The liquid container group includes an oil container group 22, a water container group 23, and a nutrient solution container group 24. The gas container group 21, the oil container group 22, and the water container group 23 are all arranged in groups of two, and the nutrient solution container group 24 is one.

[0094] The liquid replenishment device includes a water replenishment container 31 and an oil replenishment container 32.

[0095] The pressurization device includes a pressurization pump 41, a pressurization container 42 and a pressure regulator 43 connected in sequence. The outlet of the pressure regulator 43 is connected to the connecting pipeline between the gas container group 21 and the model pressure chamber 51.

[0096] The model pressure chamber 51 is a model holder with a circular steel structure. It has a top cover and fluid inlet / outlet and parameter test port on the side wall.

[0097] The side wall of the model pressure chamber 51 is also provided with annular pressure fluid control port and back pressure fluid control port.

[0098] The physical model of the outcrop core 52 measures 400×400×30mm and is encapsulated with epoxy resin.

[0099] Six cylindrical core samples were drilled at 52 screening points on the outcrop. The core samples were φ2.5×2cm in size.

[0100] Pressure sensors and saturation probes were deployed on the physical model of the outcrop core 52, and the injection and production method adopted was the one-injection-four-production method in the five-point injection and production method of oilfields.

[0101] The model pressure chamber 51 is also equipped with an accessory structure, which includes a flat cover electric moving structure, a safety valve 53, and an external coating insulation layer.

[0102] The ring pressure device includes a ring pressure tracking pump 54, which is a dual-cylinder structure.

[0103] The separation device in the production metering unit includes a gas-liquid separator 61 and an oil-water separator 62, and the metering device includes a gas flow meter 63, an oil metering pump 64, and a water metering pump 65.

[0104] The extraction metering unit also includes an interface sensor located at the oil-water separator 62.

[0105] The back pressure device includes a back pressure valve 66 and a back pressure tracking pump 67. The back pressure valve 66 is located at the outlet section of the model pressure chamber 51, and the back pressure tracking pump 67 is connected to the back pressure valve 66.

[0106] The sensors in the data acquisition and processing unit include a temperature sensor, a pressure sensor, and a saturation sensor.

[0107] The experimental setup also includes an auxiliary unit, which includes a vacuum pumping device and a wire cutting device.

[0108] The vacuuming device includes a vacuum pump 71 and a vacuum buffer container 72, and is connected to the model pressure chamber 51 and the process pipeline.

[0109] The vacuum device is also equipped with a vacuum gauge 73 and a dryer 74. The dryer 74 is located between the vacuum pump 73 and the vacuum buffer container 72, and the vacuum gauge 73 is located on the vacuum pipeline.

[0110] Example 2:

[0111] This embodiment provides a three-dimensional physical simulation experimental device for reservoir microbial flooding. The experimental device includes an injection unit, a model unit, a production metering unit, a data acquisition and processing unit, and a control unit. The injection unit, model unit, and production metering unit are connected in sequence. The data acquisition and processing unit is connected to both the model unit and the production metering unit. The control unit is connected to all other units.

[0112] The injection unit includes an injection pump 1, an intermediate container, a pressurization device, and a liquid replenishment device. The intermediate container includes a gas container group 21 and a liquid container group. The model unit includes a model pressure chamber 51 and a ring pressure device. The intermediate container and the pressurization device are both connected to the model pressure chamber 51. The liquid replenishment device is connected to both the intermediate container and the model pressure chamber 51. An outcrop core 52 is set in the model pressure chamber 51 as a three-dimensional physical model. Points are drilled on the outcrop core 52 to form a pore structure, and sensors and probes are arranged according to the injection and production method. The production metering unit includes a separation device, a metering device, and a backpressure device. The data acquisition and processing unit includes sensors and data processing software.

[0113] The injection pump 1 is a dual-cylinder pump, and there are two of them.

[0114] The intermediate containers are all installed in a temperature control component, which is a constant temperature chamber.

[0115] The liquid container group includes an oil container group 22, a water container group 23, and a nutrient solution container group 24. The gas container group 21, oil container group 22, water container group 23, and nutrient solution container group 24 are all arranged in groups, and there are two of each group.

[0116] The liquid replenishment device includes a water replenishment container 31 and an oil replenishment container 32.

[0117] The pressurization device includes a pressurization pump 41, a pressurization container 42 and a pressure regulator 43 connected in sequence. The outlet of the pressure regulator 43 is connected to the connecting pipeline between the gas container group 21 and the model pressure chamber 51.

[0118] The model pressure chamber 51 is a model holder with a circular steel structure. It has a top cover and fluid inlet / outlet and parameter test port on the side wall.

[0119] The side wall of the model pressure chamber 51 is also provided with annular pressure fluid control port and back pressure fluid control port.

[0120] The physical model of the outcrop core 52 measures 200×200×150mm and is encapsulated with epoxy resin.

[0121] Four cylindrical core samples were drilled from 52 screening points on the outcrop. The core samples were φ3×8cm in size.

[0122] Pressure sensors and saturation probes were deployed on the physical model of the outcrop core 52, and the injection and production method adopted was the one-injection-four-production method in the five-point injection and production method of oilfields.

[0123] The model pressure chamber 51 is also equipped with an accessory structure, which includes a flat cover electric moving structure, a safety valve 53, and an external coating insulation layer.

[0124] The ring pressure device includes a ring pressure tracking pump 54, which is a dual-cylinder structure.

[0125] The separation device in the production metering unit includes a gas-liquid separator 61 and an oil-water separator 62, and the metering device includes a gas flow meter 63, an oil metering pump 64, and a water metering pump 65.

[0126] The extraction metering unit also includes an interface sensor located at the oil-water separator 62.

[0127] The back pressure device includes a back pressure valve 66, a back pressure tracking pump 67, and a back pressure buffer container. The back pressure valve 66 is located at the outlet section of the model pressure chamber 51, and the back pressure tracking pump 67 is connected to the back pressure valve 66 via the back pressure buffer container.

[0128] The sensors in the data acquisition and processing unit include a temperature sensor, a pressure sensor, and a saturation sensor.

[0129] The experimental setup also includes an auxiliary unit, which includes a vacuum pumping device and a wire cutting device.

[0130] The vacuuming device includes a vacuum pump 71 and a vacuum buffer container 72, and is connected to the model pressure chamber 51 and the process pipeline.

[0131] The vacuum pumping device is also equipped with a vacuum gauge 73, which is located on the vacuum pumping pipeline.

[0132] Example 3:

[0133] This embodiment provides an experimental method for three-dimensional physical simulation of reservoir microbial flooding. The experimental method uses the apparatus in Embodiment 1 and includes the following steps:

[0134] (1) Outcrop core 52 was selected as the physical model. After drilling, layout, and encapsulation, six cylindrical small cores were drilled from selected points on outcrop core 52. The size of the small cores was φ2.5×2cm. The well network was simulated on outcrop core 52 using the one-injection-four-production method in the five-point injection and production method of oilfields. The model was equipped with 25 pressure sensors and 36 saturation probes. The simulated well network distribution diagram is shown below. Figure 2 As shown, the physical model was encapsulated with epoxy resin. After encapsulation, the model was evacuated and saturated with water. The porosity and permeability of the core model were calculated. The porosity was 21.81%, and the permeability was 397.5 × 10⁻⁶. -3 μm 2 Then it is installed in the model pressure chamber 51. After water is injected by opening the water inlet valve and the upper exhaust valve, it is heated and pressurized. The temperature after heating is 60°C. After the set temperature is reached, it is pressurized to the target value of 7MPa.

[0135] (2) Turn on injection pump 1 and run data acquisition and processing unit. First, replace water with saturated oil at a displacement rate of 2.5 mL / min. Calculate the initial oil saturation as 64%. Then, perform one water flood at a displacement rate of 2.5 mL / min until the water content is 98%. Record the recovery rate of one water flood as 25.3%.

[0136] (3) After the first water flooding in step (2), microbial displacement is performed. During the microbial displacement, a microbial system is injected. The microbial system is in the form of a microbial nutrient solution with a microbial concentration of 5 wt%. The microbial species is Bacillus subtilis. The injection volume of the microbial system is 0.6 PV, and the injection rate is 2.5 mL / min. For every 0.2 PV of microbial system injected, samples are taken from different measurement points to detect the microbial concentration. After the injection is completed, the system is cultured for 4 days, followed by a second water flooding at a displacement rate of 2.5 mL / min until the water content reaches 98%. The recovery rate of the second water flooding is recorded. During the second water flooding process, for every 0.2 PV of water injected, samples are taken from different measurement points to detect the microbial concentration and calculate the surface tension. The microbial concentration detected at one measurement point is 2 × 10⁻⁶. 8 The surface tension is 38 mN / m, with a density of 1 / mL.

[0137] (4) Turn off injection pump 1, stop running data acquisition and processing unit, depressurize and drain water. When depressurizing, open the exhaust valve of model pressure chamber 51. After the pressure drops to normal pressure, open the water outlet valve to drain water. Open model pressure chamber 51, disassemble core model and perform subsequent model slicing.

[0138] Example 4:

[0139] This embodiment provides an experimental method for three-dimensional physical simulation of reservoir microbial flooding. The experimental method uses the apparatus in Embodiment 1 and includes the following steps:

[0140] (1) Select outcrop core 52 as physical model. After drilling, layout and encapsulation, 6 cylindrical small cores are drilled from the selected points on the outcrop core 52. The size of the small core is φ2.5×2cm. The well network is simulated by the one injection and four production method in the five-point injection and production method of oilfield. The number of pressure sensors and saturation probes on the model is 20. The model is encapsulated with epoxy resin. After encapsulation, the physical model is evacuated and water is passed through to saturation. The porosity and permeability of the core model are calculated. The porosity is 17.15% and the permeability is 209mD. Then it is installed in the model pressure chamber 51. After water is injected by opening the water inlet valve and the upper exhaust valve, it is heated and pressurized. The temperature after heating is 70℃. After reaching the set temperature, it is pressurized to the target value of 10MPa.

[0141] (2) Turn on injection pump 1 and run data acquisition and processing unit. First, replace water with saturated oil at a displacement rate of 0.5 mL / min. Calculate the initial oil saturation as 69%. Then, perform one water drive at a displacement rate of 1 mL / min until the water content is 95%. Record the recovery rate of one water drive as 33%.

[0142] (3) After the first water flooding in step (2), microbial displacement is performed. During the microbial displacement, a microbial system is injected. The microbial system is in the form of a microbial nutrient solution with a microbial concentration of 4 wt%. The microbial species is Bacillus subtilis. The injection volume of the microbial system is 0.4 PV, and the injection rate is 1 mL / min. For every 0.1 PV of microbial system injected, samples are taken from different measurement points to detect the microbial concentration. After injection, the system is cultured for 2 days, followed by a second water flooding at a displacement rate of 0.8 mL / min until the water content reaches 95%. The recovery rate of the second water flooding is recorded. During the second water flooding process, for every 0.1 PV of water injected, samples are taken from different measurement points to detect the microbial concentration and calculate the surface tension. The microbial concentration detected at one measurement point is 2 × 10⁻⁶. 8 The surface tension is 34 mN / m, with a density of 1 / mL.

[0143] (4) Turn off injection pump 1, stop running data acquisition and processing unit, depressurize and drain water. When depressurizing, open the exhaust valve of model pressure chamber 51. After the pressure drops to normal pressure, open the water outlet valve to drain water. Open model pressure chamber 51, disassemble core model and perform subsequent model slicing.

[0144] Example 5:

[0145] This embodiment provides an experimental method for three-dimensional physical simulation of reservoir microbial flooding. The experimental method uses the apparatus in Embodiment 2 and includes the following steps:

[0146] (1) Select outcrop core 52 as physical model. After drilling, layout and encapsulation, four cylindrical small cores are drilled from the selected points on the outcrop core 52. The size of the small cores is φ3×8cm. The well network is simulated by the one injection and four production method in the five-point injection and production method of oilfield. The number of pressure sensors and saturation probes on the model is 16. The model is encapsulated with epoxy resin. After encapsulation, the physical model is evacuated and water is passed through to saturation. The porosity and permeability of the core model are calculated. The porosity is 17.2% and the permeability is 559mD. Then it is installed in the model pressure chamber 51. After water is injected by opening the water inlet valve and the upper exhaust valve, it is heated and pressurized. The temperature after heating is 50℃. After reaching the set temperature, it is pressurized to the target value of 8MPa.

[0147] (2) Turn on injection pump 1 and run data acquisition and processing unit. First, replace water with saturated oil at a displacement rate of 5 mL / min. Calculate the initial oil saturation as 80%. Then, perform one water drive at a displacement rate of 4 mL / min until the water content is 99%. Record the recovery rate of one water drive as 29%.

[0148] (3) After the first water flooding in step (2), microbial displacement is performed. During the microbial displacement, a microbial system is injected. The microbial system is in the form of a microbial nutrient solution with a microbial concentration of 6 wt% and the microbial species being Pseudomonas aeruginosa. The injection volume of the microbial system is 0.8 PV, and the injection rate is 4 mL / min. For every 0.4 PV of microbial system injected, samples are taken from different measurement points to detect the microbial concentration. After injection, the system is cultured for 7 days, followed by a second water flooding at a displacement rate of 4.5 mL / min until the water content reaches 99%. The recovery rate of the second water flooding is recorded. During the second water flooding process, for every 0.4 PV of water injected, samples are taken from different measurement points to detect the microbial concentration and calculate the surface tension. The microbial concentration detected at one measurement point is 2 × 10⁻⁶. 6 The surface tension is 44 mN / m, with a density of 1 / mL.

[0149] (4) Turn off injection pump 1, stop running data acquisition and processing unit, depressurize and drain water. When depressurizing, open the exhaust valve of model pressure chamber 51. After the pressure drops to normal pressure, open the water outlet valve to drain water. Open model pressure chamber 51, disassemble core model and perform subsequent model slicing.

[0150] As can be seen from the above embodiments, the present invention designs a three-dimensional physical simulation experimental device for microbial displacement, with a model pressure chamber and a core model as the main body, and equipped with an injection unit and a production metering unit to form a displacement process unit. Combined with a data acquisition and processing unit and a control unit, it performs real-time detection and control, simulates reservoir physical properties and microbial growth conditions, and combines pressure, resistivity and biochemical indicators for rapid tracking and detection to evaluate the effect of microbial oil displacement. It also conducts in-depth research on the characteristics of microbial growth and metabolism, seepage laws and oil displacement mechanisms, optimizes the microbial well network and supporting process research, and provides guidance for the actual oil production process of reservoirs. The device has a reasonable structural design, a high degree of automation, and a wide range of applications.

[0151] The applicant declares that the present invention is illustrated through the above embodiments with detailed apparatus and methods, but the present invention is not limited to the above detailed apparatus and methods, that is, it does not mean that the present invention must rely on the above detailed apparatus and methods to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions for the apparatus of the present invention, additions of auxiliary devices, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A three-dimensional physical simulation experimental device for oil reservoir microbial flooding, characterized in that, The experimental apparatus includes an injection unit, a model unit, a extraction metering unit, a data acquisition and processing unit, and a control unit. The injection unit, model unit, and extraction metering unit are connected in sequence. The data acquisition and processing unit is connected to both the model unit and the extraction metering unit. The control unit is connected to all other units. The injection unit includes an injection pump, an intermediate container, a pressurization device, and a liquid replenishment device. The intermediate container includes a gas container group and a liquid container group. The model unit includes a model pressure chamber and a ring pressure device. The intermediate container and the pressurization device are both connected to the model pressure chamber. The liquid replenishment device is connected to both the intermediate container and the model pressure chamber. An outcrop core is set in the model pressure chamber as a three-dimensional physical model. Points are drilled on the outcrop core to form a pore structure, and sensors and probes are arranged according to the injection and production method. The production metering unit includes a separation device, a metering device, and a backpressure device. The data acquisition and processing unit includes sensors and data processing software.

2. The experimental apparatus according to claim 1, characterized in that, The injection pump is a dual-cylinder pump, and the number of such pumps is at least two. Preferably, the intermediate containers are all installed in a temperature control component, which includes a constant temperature chamber; Preferably, the liquid container group includes a water container group, an oil container group, and a nutrient solution container group; Preferably, the gas container group and each liquid container group are arranged in groups, and each group has at least two units; Preferably, the fluid replenishment device includes a water replenishment container and an oil replenishment container; Preferably, the pressurization device includes a pressurization pump, a pressurization container, and a pressure regulator connected in sequence, and the outlet of the pressure regulator is connected to the connecting pipeline between the gas container group and the model pressure chamber.

3. The experimental apparatus according to claim 1 or 2, characterized in that, The model pressure chamber is a model holder with a circular steel structure. It has a top cover and fluid inlet / outlet and parameter test port on the side wall. Preferably, the side wall of the model pressure chamber is also provided with annular pressure fluid control port and back pressure fluid control port; Preferably, the physical model of the outcrop core is no larger than 500×500×500mm and is encapsulated with epoxy resin. Preferably, at selected locations on the outcrop core, 2 to 8 small cylindrical cores are drilled, the size of which is φ(2 to 3) × (2 to 10) cm; Preferably, pressure sensors and saturation probes are deployed on the outcrop core physical model, and the injection and production method adopted is the one-injection-four-production method in the five-point injection and production method of oilfields; Preferably, the model pressure chamber is further provided with an accessory structure, which includes a flat-cover electric moving structure, a safety valve, and an external coating insulation layer; Preferably, the ring pressure device includes a ring pressure tracking pump, which is a dual-cylinder structure.

4. The experimental apparatus according to any one of claims 1-3, characterized in that, The separation device in the produced metering unit includes a gas-liquid separator and an oil-water separator, and the metering device includes a gas flow meter, an oil metering pump, and a water metering pump. Preferably, the extraction metering unit further includes an interface sensor located at the oil-water separator; Preferably, the backpressure device includes a backpressure valve and a backpressure tracking pump, wherein the backpressure valve is located at the outlet section of the model pressure chamber, and the backpressure tracking pump is connected to the backpressure valve; Preferably, the sensors in the data acquisition and processing unit include a temperature sensor, a pressure sensor, and a saturation sensor.

5. The experimental apparatus according to any one of claims 1-4, characterized in that, The experimental setup also includes an auxiliary unit, which includes a vacuum pumping device and a wire cutting device. Preferably, the vacuuming device includes a vacuum pump and a vacuuming buffer container, and the vacuuming device is connected to the model pressure chamber and the process pipeline. Preferably, the vacuuming device is further equipped with a vacuum gauge and a dryer, the dryer being located between the vacuum pump and the vacuuming buffer container, and the vacuum gauge being located on the vacuuming pipeline.

6. An experimental method for conducting three-dimensional physical simulation of reservoir microbial flooding using the experimental apparatus described in any one of claims 1-5, characterized in that, The experimental method includes the following steps: (1) Select outcrop rock cores as physical models. After drilling, laying and sealing, install them in the model pressure chamber, inject water and heat and pressurize them until the target value is reached. (2) Turn on the injection pump and run the data acquisition and processing unit. First, replace the water with saturated oil to calculate the initial oil saturation. Then, perform one water drive and record the water drive recovery rate. (3) After the first water flooding in step (2), microbial displacement is carried out. After the injection is completed, the microorganisms are cultured and then subjected to a second water flooding. The recovery rate of the second water flooding is recorded, and the data collected during the displacement process is processed. (4) Turn off the injection pump, stop the operation of the data acquisition and processing unit, depressurize and drain the water before disassembling the model.

7. The experimental method according to claim 6, characterized in that, In step (1), 2 to 8 cylindrical cores are drilled from the selected points on the outcrop core. The size of the core is φ(2 to 3) × (2 to 10) cm. Preferably, the number of sensors deployed on the outcrop core in step (1) is 16 to 25, and the number of probes is 25 to 36; Preferably, the encapsulation in step (1) is performed using epoxy resin; Preferably, the encapsulated physical model described in step (1) is vacuumed and saturated with water to calculate the porosity and permeability of the core model; Preferably, the encapsulated physical model described in step (1) is installed in the model pressure chamber, the water source is connected to the water inlet of the chamber, the water inlet valve and the upper exhaust valve are opened when water is injected, and the exhaust valve indicates that the chamber is full of water after water comes out. Then the valves are closed.

8. The experimental method according to claim 6 or 7, characterized in that, In step (2), the displacement rate of water when the saturated oil displaces water is 0.5 to 5 mL / min, and bound water is established by water displacement with oil. Preferably, the displacement rate during the first water flooding in step (2) is 0.5 to 5 mL / min, and the displacement is carried out until the water content is 95 to 99%. Preferably, the primary waterflood recovery rate in step (2) refers to the proportion of oil produced during a primary waterflood to the amount of saturated oil.

9. The experimental method according to any one of claims 6-8, characterized in that, In step (3), the microbial replacement is performed by injecting a microbial system, wherein the microbial system is in the form of a microbial nutrient solution with a microbial concentration of 4-6 wt%. Preferably, the types of microorganisms in the microbial system include Bacillus subtilis or Pseudomonas aeruginosa; Preferably, the injection volume of the microbial system during microbial displacement in step (3) is 0.3 to 0.8 PV, and the injection rate is 0.5 to 5 mL / min; Preferably, during the microbial displacement process in step (3), samples are taken from different measurement points to detect the microbial concentration for every 0.1–0.5 PV of microbial system injected; Preferably, the microorganisms are cultured for 0 to 7 days after the injection of the microorganisms in step (3); Preferably, the displacement rate during the secondary water flooding in step (3) is 0.5 to 5 mL / min, and the displacement is carried out until the water content is 95 to 99%. Preferably, during the secondary water drive process described in step (3), samples are taken from different measurement points to detect the microbial concentration and surface tension for every 0.1 to 0.5 PV of water injected.

10. The experimental method according to any one of claims 6-9, characterized in that, When depressurizing as described in step (4), open the exhaust valve of the model pressure chamber until the pressure drops to atmospheric pressure, then open the water outlet valve to drain the water. Preferably, after depressurization and drainage in step (4), the model pressure chamber is opened, the core model is disassembled, and subsequent model slicing is performed.

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