WO2022148193A1 - Microscopic visualization experimental device and method for simulating fluid displacement under high temperature and high pressure - Google Patents

Abstract

A microscopic visualization experimental device for simulating fluid displacement under high temperature and high pressure, the device comprising a reservoir temperature and pressure coordination control system, a displacement reaction system, a data collecting and processing system and an auxiliary system. A microscopic visualization experimental method for high-temperature and high-pressure gas flooding of deep oil reservoir, comprising the following steps: mounting a glass etching model (22); injecting a confining pressure liquid and controlling confining pressure; heating the confining pressure liquid in an annular reservoir confining-pressure cavity (15); placing the glass etching model (22) under a microscope (10); respectively filling crude oil and a displacement fluid medium into a heated thermostatic piston container (2), and regulating a back pressure unit (18) to simulated formation pressure; and carrying out a water injection and gas injection displacement experiment. The device and the method can be used for simulating the distribution state of oil, water and gas and fluid migration characteristics in a micro/nano-scale pore structure, quantitatively characterize a starting mechanism of microscopic residual oil in high-temperature and high-pressure water flooding, gas flooding and chemical flooding, and have important guiding significance for judging the distribution and magnitude of oil and water saturation in the process of oilfield reservoir development.

Description

Microscopic visualization experimental device and method for simulating fluid displacement under high temperature and high pressure technical field

The invention relates to the technical field of microscopic displacement, in particular to a microscopic visualization experimental device and an experimental method for simulating fluid displacement under high temperature and high pressure conditions.

Background technique

With more and more exploration and development activities in deeper and more complex formations worldwide, it is more and more difficult to tap the remaining oil under the conditions of deep high temperature and high pressure. Especially when the oilfield enters the stage of high water-cut development, the production declines, and the potential targets for mining and mining change from a large area of connected remaining oil to a highly dispersed but relatively localized area. Due to the unclear understanding of the microscopic occurrence state and distribution law of the remaining oil, Seriously hindered the next step to tap the remaining oil potential. Therefore, it is particularly important to prove the migration characteristics of fluids with different properties in micro- and nano-scale channels and the law of remaining oil enrichment under high temperature and high pressure conditions for reservoir production and development.

The existing micro-displacement experimental method is to use real rock after grinding and put it into matching grooves, seal the surrounding of the rock at the same time, and inject fluid from one side to study the flow characteristics of the fluid in the rock. However, this technology has great limitations. On the one hand, the rock will be worn during the use process, and the basic parameters of the rock will change with the experimental process, and the used rock is not easy to wash, and the repeatability is low; in addition, conventional micro-flooding There are two main problems with the replacement experimental device. First, due to the deep burial of complex oil reservoirs and the high temperature and pressure (70MPa, 150°C), it is difficult for conventional experimental devices to reproduce the high temperature and high pressure conditions of real reservoirs; on the other hand, Due to the small pore size, it is difficult for conventional experimental devices to visualize the migration laws of fluids with different properties in micro- and nano-scale channels, and to analyze the distribution laws of remaining oil qualitatively and quantitatively.

Therefore, it is necessary to comprehensively and deeply understand the flow laws of fluids of different properties in micro- and nano-scale channels, and at the same time, to quantitatively describe the oil-water saturation distribution during the displacement process of micro-pore structure, which requires the experimental device to restore complex formation conditions as much as possible. On the basis of this, new requirements are also put forward on the ability to present the real-life behavior of fluid flow in the pore throat, the flexibility of experimental operation, and the accuracy of experimental data.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a microscopic visualization experimental device and experimental method for simulating fluid displacement under high temperature and high pressure conditions in order to solve the above-mentioned deficiencies of the prior art.

The technical problems to be solved are realized by the following technical solutions:

A microscopic visualization experimental device for simulating fluid displacement under high temperature and high pressure conditions, including a reservoir temperature and pressure coordinated control system, a displacement reaction system, a data acquisition and video recording system, and an auxiliary system;

The reservoir temperature and pressure coordinated control system includes a high-pressure sealing holder, a sapphire window for easy observation is arranged on the high-pressure sealing holder, and a reservoir confining pressure ring cavity is formed inside the high-pressure sealing holder; the The reservoir confining pressure ring cavity is connected with the shell inlet of the high temperature heating vessel through the fluid heating output pipeline, and the shell layer outlet of the high temperature heating vessel is connected with the reservoir confining pressure annular cavity through the fluid heating input pipeline, which is arranged on the fluid heating input pipeline. There is a high-pressure magnetic circulation pump; the reservoir confining pressure ring cavity is connected with the confining pressure monitoring pipeline, and a confining pressure tracking pump is arranged on the confining pressure monitoring pipeline;

The displacement reaction system includes a high-pressure injection pump, a heated thermostatic piston container, a glass etching model and a back pressure unit. The glass etching model is placed inside the high-pressure sealing holder, and an injection end is provided at one end of the glass etching model. , and the injection end is connected with one end of the model fluid injection pipe, the other end of the model fluid injection pipe is connected with the pipe layer outlet of the high temperature heating vessel, the pipe layer inlet of the high temperature heating vessel is connected with the main fluid conveying pipe, and the main fluid conveying pipe is connected. The pipeline is connected with the outlet end of the heating thermostatic piston container, and the inlet end of the heating thermostatic piston container is connected to the high-pressure injection pump through the pumping pipeline; the other end of the glass etching model is provided with a production end, and the production end is produced through the model fluid The pipeline is connected to the back pressure unit, and a condenser is arranged on the model fluid production pipeline;

The data acquisition and video recording system includes a temperature sensor, a pressure sensor, a microscope, a data acquisition and processing system and a computer. The temperature sensor is respectively arranged on the heating thermostatic piston container and the high temperature heating container, and the pressure sensor is respectively arranged on the main fluid conveying pipeline, On the confining pressure monitoring pipeline and the model fluid production pipeline; the microscope is set at the position facing the sapphire window, and the data acquisition and processing system is set on the observation end of the eyepiece of the microscope;

The auxiliary system includes an evacuation system and a gas pressurization system, the evacuation system is connected to the main fluid conveying pipeline through a model evacuation pipeline, and the evacuation system is also communicated with the reservoir confining pressure annular cavity through the annular cavity evacuation pipeline; The gas pressurization system is connected with the main pipeline of fluid conveying;

The temperature sensor, pressure sensor, data acquisition and processing system, confining pressure tracking pump, gas boosting system and vacuuming system are all connected with the computer.

Preferably, a plurality of the heating thermostatic piston containers are provided and arranged in parallel.

Preferably, a plurality of the pressure sensors are arranged on the main fluid conveying pipeline, which are respectively a low-range pressure sensor, a medium-range pressure sensor and a high-range pressure sensor, and the pressure sensors arranged on the confining pressure monitoring pipeline and the model fluid production pipeline are all It is a high-range pressure sensor.

Preferably, the back pressure unit includes a high precision back pressure valve, a buffer tank and a back pressure pump.

Preferably, the annular cavity vacuuming pipeline is connected with a first venting pipeline, and a first venting valve is arranged on the first venting pipeline; the pumping pipeline is connected with a second venting pipeline, which is provided on the second venting pipeline There is a second vent valve.

Preferably, a first valve is arranged on the confining pressure monitoring pipeline, a second valve is arranged on the model fluid injection pipeline, and a third valve is arranged on the low-range pressure sensor pipeline connected to the main fluid conveying pipeline. A fourth valve is arranged on the mid-range pressure sensor pipeline of the main fluid conveying pipeline; a fifth valve, a sixth valve and a seventh valve are respectively arranged on the branch pipeline connecting the pumping pipeline to the inlet end of the heating thermostatic piston container.

Preferably, a manual bevel adjustment bracket is provided at the bottom of the high-pressure sealing holder.

The invention also provides a microscopic visualization experimental method for oil displacement by high temperature and high pressure gas in deep oil reservoirs, which adopts a microscopic visualization experimental device for oil displacement by high temperature and high pressure gas in deep oil reservoirs, and the device includes a reservoir temperature and pressure coordination control system, a displacement reaction system, Data acquisition and video recording systems and auxiliary systems;

The reservoir temperature and pressure coordinated control system includes a high-pressure sealing holder, a sapphire window for easy observation is arranged on the high-pressure sealing holder, and a reservoir confining pressure ring cavity is formed inside the high-pressure sealing holder; the The reservoir confining pressure ring cavity is connected with the shell inlet of the high temperature heating vessel through the fluid heating output pipeline, and the shell layer outlet of the high temperature heating vessel is connected with the reservoir confining pressure annular cavity through the fluid heating input pipeline, which is arranged on the fluid heating input pipeline. There is a high-pressure magnetic circulation pump; the reservoir confining pressure ring cavity is connected with the confining pressure monitoring pipeline, and a confining pressure tracking pump is arranged on the confining pressure monitoring pipeline;

The displacement reaction system includes a high-pressure injection pump, a heated thermostatic piston container, a glass etching model and a back pressure unit. The glass etching model is placed inside the high-pressure sealing holder, and an injection end is provided at one end of the glass etching model. , and the injection end is connected with one end of the model fluid injection pipe, the other end of the model fluid injection pipe is connected with the pipe layer outlet of the high temperature heating vessel, the pipe layer inlet of the high temperature heating vessel is connected with the main fluid conveying pipe, and the main fluid conveying pipe is connected. The pipeline is connected with the outlet end of the heating thermostatic piston container, and the inlet end of the heating thermostatic piston container is connected to the high-pressure injection pump through the pumping pipeline; the other end of the glass etching model is provided with a production end, and the production end is produced through the model fluid The pipeline is connected to the back pressure unit, and a condenser is arranged on the model fluid production pipeline;

The data acquisition and video recording system includes a temperature sensor, a pressure sensor, a microscope, a data acquisition and processing system and a computer. The temperature sensor is respectively arranged on the heating thermostatic piston container and the high temperature heating container, and the pressure sensor is respectively arranged on the main fluid conveying pipeline, On the confining pressure monitoring pipeline and the model fluid production pipeline; the microscope is set at the position facing the sapphire window, and the data acquisition and processing system is set on the observation end of the eyepiece of the microscope;

The auxiliary system includes an evacuation system and a gas pressurization system, the evacuation system is connected to the main fluid conveying pipeline through a model evacuation pipeline, and the evacuation system is also communicated with the reservoir confining pressure annular cavity through the annular cavity evacuation pipeline; The gas pressurization system is connected with the main pipeline of fluid conveying;

The temperature sensor, pressure sensor, data acquisition and processing system, confining pressure tracking pump, gas pressurization system and vacuum pumping system are all connected with the computer;

The experimental method includes the following steps:

The first step is to make a glass etching model that simulates the rock sample under actual reservoir conditions;

The second step is to install the glass etching model in the high-pressure sealing holder, and vacuum the reservoir confining pressure ring cavity and the glass etching model through the vacuum pumping system;

The third step is to inject confining pressure liquid into the confining pressure ring cavity of the reservoir through the confining pressure monitoring pipeline, and control the confining pressure through the confining pressure tracking pump, so that the pressure in the confining pressure ring cavity of the reservoir is higher than the internal pressure of the glass etching model; Turn on the high-pressure magnetic circulation pump, and heat the confining pressure fluid in the confining pressure ring cavity of the reservoir through the high-temperature heating vessel until the formation temperature is reached;

The fourth step is to place the glass etching model under the microscope, and adjust the focusing position and magnification of the microscope until the data acquisition and processing system can collect a clear micro-nano-scale channel image inside the glass etching model;

The fifth step is to put the crude oil and the displacement fluid medium into the heated thermostatic piston container respectively, and adjust the back pressure unit to the simulated formation pressure; Glass etching model saturated crude oil;

The sixth step is to switch the fluid in the main fluid transport pipeline to the displacing fluid medium water, and carry out the water displacing oil displacing experiment. During the displacing process, the data acquisition and processing system will collect images in real time. When the remaining oil in the oil is no longer changed, the displacement is stopped;

Step 7: Switch the fluid in the main fluid delivery pipeline to high-pressure gas, and carry out the high-pressure gas flooding experiment for the remaining oil through the gas booster system. Control the displacement mode to be continuous gas flooding or intermittent gas flooding. The system collects images in real time, and stops the displacement when the remaining oil in the micro- and nano-scale channels of the glass etching model no longer changes;

The eighth step, after the displacement is completed, the experiment ends, and the experimental results are obtained by analyzing the recorded data of the temperature sensor and the pressure sensor and the fluid flow characteristics in the micro- and nano-scale channels at the corresponding time of the glass etching model.

Preferably, through the preprocessing, segmentation, recovery and correction of the scanned image of the rock sample, the pore throat structure map that can reflect the characteristics of the deep oil reservoir is clearly defined, and the glass etched glass is prepared by the microfluidic chip fabrication method. Model.

Preferably, the confining pressure is controlled by the confining pressure tracking pump, so that the pressure in the confining pressure ring cavity of the reservoir is 2MPa higher than the internal pressure of the glass etching model.

Preferably, the displacing fluid medium is dyed with the same soluble dye before being loaded into the heated thermostatic piston container.

Preferably, when the micro-nano pores in the glass etching model are smaller than 10 microns, before injecting crude oil, the glass etching model is first saturated with kerosene.

Preferably, the injection speed of the high-pressure injection pump to the crude oil and the displacement fluid medium is not higher than 0.02 mL/min.

Preferably, a first valve is arranged on the confining pressure monitoring pipeline, a second valve is arranged on the model fluid injection pipeline, and the second valve is a three-way valve; when the crude oil and the displacement fluid medium need to be switched, or the When the displacement fluid medium is switched between each other, the first valve needs to be closed first, and then the fluid in the main fluid delivery pipeline and the model fluid injection pipeline is discharged through the second valve.

Preferably, the gas component of the high-pressure gas is a hydrocarbon gas mixed with C ₁ -C ₄ in any ratio, and N ₂ or CO ₂ can also be used.

Preferably, after the experiment, the displacement medium is replaced with petroleum ether to flush the main pipeline of cleaning fluid, the model fluid injection pipeline and the glass etching model.

Preferably, the annular cavity vacuuming pipeline is connected with a first venting pipeline, and a first venting valve is arranged on the first venting pipeline; the pumping pipeline is connected with a second venting pipeline, which is provided on the second venting pipeline There is a second vent valve; after the experiment, the fluid in the confining pressure ring cavity of the reservoir is discharged through the first vent valve, and the fluid in the heated thermostatic piston container is discharged through the second vent valve.

The above-mentioned gas injection flooding and water flooding process switch the displacement medium in the same way.

The above-mentioned displacement fluid medium includes salinity water and high-pressure gas.

The beneficial technical effects of the present invention are:

The invention adopts the visual micro-nano-scale pore-throat model, that is, the glass etching model, to simulate the internal pore-throat characteristics of the actual rock, and realizes the fluid in the micro-nano-scale channel under the condition of high temperature and high pressure through the reservoir temperature and pressure coordinated control system and the displacement reaction system. Combined with the data acquisition and video system to observe the microscopic fluid migration characteristics in porous media, the quantification of the remaining oil-water saturation in the microscopic pore structure during the microscopic model high-pressure gas flooding experiment is truly realized, which is very important for the oilfield reservoir development process. It is of great guiding significance to judge the distribution and size of oil and gas water saturation in

The invention can be used to simulate the oil-water-gas distribution state and fluid migration characteristics in the micro-nano-scale pore structure, and quantitatively characterize the starting mechanism of the microscopic remaining oil in high-temperature and high-pressure water flooding, gas flooding and chemical flooding.

In addition, the experimental device adopted by the experimental method of the present invention also has the following two key design points:

(1) The traditional heating mode mostly adopts the indirect heating method in which the heating coil is installed on the outer wall of the heating jacket. The disadvantages are that the fluid heating rate is slow, the heat dissipation is fast, and the temperature supply is unstable. The volume of the fluid medium may be compressed or expanded due to the temperature difference between the inside and outside, and the injection speed and pressure of the displacement medium cannot be effectively controlled; the present invention changes the traditional heating mode to the direct heating mode of the fluid in the kettle, and adopts high temperature heating The heating tube in the container is placed in the heating jacket to directly contact and heat the fluid flowing through the heating jacket; the high-pressure magnetic circulation pump is used as the power source to realize the circulation of the fluid between the confining pressure ring cavity of the reservoir and the high-temperature heating container, ensuring the The temperature and pressure of the fluid in the confining ring cavity can be balanced; at the same time, the total displacement inlet pipeline is preheated into the glass etching chip through the high-pressure heat exchange container, so that the entire heating system of the model belongs to the same heating system, which ensures the entry into the glass etching chip. There is no temperature difference between the fluid of the chip and the confining pressure ring cavity, which makes the heating equilibration time shorter, the visualization model is heated more evenly, and the accuracy of the experiment is improved.

(2) In the present invention, the confining pressure tracking pump is used to continuously monitor the pressure condition in the circulating pipeline, and the fluid in the circulating pipeline can be compensated and depressurized; the back pressure unit is used to raise the pressure of the entire displacement system to control the formation displacement. The pressure condition of the medium, the use of high-precision back pressure valve can accurately ensure the displacement pressure gradient, and more flexibly control the pressure at the outlet end during the displacement process; at the same time, a condenser is added at the outlet, which can effectively reduce the temperature of the displacement medium and ensure that the The service life of the high precision back pressure valve. Displacement differential pressure gradient control can be realized through the setting of the back pressure unit and the like.

The present invention comprehensively considers the limitations of traditional microscopic displacement experimental devices, and constructs a physical simulation device suitable for microscopic visualization experimental research of high temperature and high pressure fluid displacement on the basis of using a microscopic visualization model to simulate the pore throat characteristics of formation rocks. experimental method. The invention adopts the method of "direct heating of confining pressure ring cavity" to simulate the actual temperature of the reservoir, continuously monitors the pressure condition in the circulation pipeline through the high-pressure tracking pump, and supplements the fluid pressure in the circulation pipeline in time; One or more fluids are injected into the glass etched chip, and measured by digital sensors to realize real-time acquisition of temperature and pressure data when the fluid flows in micro-nano-scale micro-nano-scale channels; through microscope observation, different fluids can pass through the microscopic visualization model. Image observation and acquisition; further, through the combination of microscopic observation and quantitative analysis, the mechanism is fundamentally understood, and the study of the flow characteristics of different fluids flowing through micro-, nano-, micro- and nano-scale channels is realized.

Description of drawings

FIG. 1 is a schematic diagram of the structural principle of the experimental device used in the microscopic visualization experimental method of the present invention.

Fig. 2 is a characteristic diagram of the distribution of residual oil in water flooding to gas injection under high temperature and high pressure in a specific application example of the present invention.

In the figure: 1-high pressure injection pump; 2-heated thermostatic piston container; 3-gas booster system; 4-temperature sensor; 5-low-range pressure sensor; 6-medium-range pressure sensor; 7-high-range pressure sensor; 8 -Vacuum pumping system; 9-First valve; 10-Microscope; 11-Data acquisition and processing system; 12-Computer; 13-High temperature heating vessel; 14-High pressure magnetic circulation pump; High-pressure sealing holder; 17-Confining pressure tracking pump; 18-Back pressure unit; 19-Condenser; 20-Manual angle adjustment bracket; 21-Clamp; 22-Glass etching model; Fluid heating output pipeline; 25-fluid heating input pipeline; 26-ring cavity vacuuming pipeline; 27-confining pressure monitoring pipeline; 28-model fluid injection pipeline; 29-fluid conveying main pipeline; 30-pumping pipeline; 31-model Fluid production pipeline, 32-model vacuuming pipeline, 33-second valve, 34-third valve, 35-fourth valve, 36-fifth valve, 37-sixth valve, 38-seventh valve, 39- First vent valve, 40-Second vent valve.

Detailed ways

The following examples are to further illustrate the present invention, but the present invention is not limited thereto. Because the present invention is relatively complex, the embodiments only describe the invention points of the present invention in detail, and the existing technology can be adopted for the parts that are not described in detail in the present invention.

Example 1

A microscopic visualization experimental method for oil displacement by high temperature and high pressure gas in a deep reservoir adopts a microscopic visualization experimental device, as shown in Figure 1, including a reservoir temperature and pressure coordinated control system, a displacement reaction system, a data acquisition and video system, and an auxiliary system. The main function of the reservoir temperature and pressure coordination control system is to simulate the formation pressure and temperature of the rock formation in the real reservoir environment. The reservoir temperature and pressure coordination control system includes a high-pressure sealing holder 16 , a sapphire window 23 for easy observation is arranged on the high-pressure sealing holder 16 , and a reservoir confining pressure ring cavity 15 is formed inside the high-pressure sealing holder 16 . The reservoir confining pressure ring cavity 15 is connected to the shell inlet of the high temperature heating vessel 13 through the fluid heating output pipe 24, and the shell outlet of the high temperature heating vessel 13 is communicated with the reservoir confining pressure ring cavity 15 through the fluid heating input pipe 25. , a high-pressure magnetic circulation pump 14 is arranged on the fluid heating input pipeline 25 . The reservoir confining pressure ring cavity 15 is connected with a confining pressure monitoring pipeline 27 , and a confining pressure tracking pump 17 is arranged on the confining pressure monitoring pipeline 27 . The confining pressure tracking pump 17 is composed of a confining pressure pump and an automatic tracker.

The displacement reaction system is mainly used as a microscopic displacement site of reservoir fluid, and characterizes the seepage characteristics and distribution of remaining oil after water flooding, gas flooding and chemical flooding. The displacement reaction system includes a high-pressure injection pump 1, a heated thermostatic piston vessel 2, a glass etching model 22 and a back pressure unit 18. The glass etching model 22 is placed inside the high-pressure sealing holder 16, that is, in the reservoir confining pressure ring. In the space of the cavity 15 , both ends of the glass etching model 22 are clamped and fixed by the clamps 21 . One end of the glass etching model 22 is provided with an injection end, and the injection end is connected with one end of the model fluid injection pipe 28, and the other end of the model fluid injection pipe 28 is connected with the outlet of the pipe layer of the high temperature heating container 13, and the high temperature heating container The pipe layer inlet of 13 is connected to the main pipeline 29 for fluid delivery. The main fluid delivery pipeline 29 is connected to the outlet end of the heating thermostatic piston container 2 , and the inlet end of the heating thermostatic piston container 2 is connected to the high pressure injection pump 1 through the pumping pipeline 30 . A production end is provided at the other end of the glass etching model 22 , and the production end is connected to the back pressure unit 18 through a model fluid production pipeline 31 , and a condenser 19 is arranged on the model fluid production pipeline 31 . By connecting the back pressure unit 18 and the condenser 19, the displacement pressure gradient across the glass etching model 22 can be controlled, and the produced fluid can be automatically recorded and collected.

The main functions of the data acquisition and video recording system are to record the flow state of the displacement fluid in real time, and to collect the temperature and pressure data of the reservoir temperature and pressure coordinated control system and the displacement reaction system. The data acquisition and video recording system includes a temperature sensor 4, a pressure sensor, a microscope 10, a data acquisition and processing system 11 and a computer 12. The temperature sensor 4 is respectively arranged on the heating thermostatic piston container 2 and the high temperature heating container 13, and the pressure sensor is respectively arranged on the On the main fluid delivery pipeline 29 , the confining pressure monitoring pipeline 27 and the model fluid production pipeline 31 . The microscope 10 is placed at a position facing the sapphire viewing window 23 and directly above the glass model etching model 22 . The eyepiece of the microscope 10 is equipped with a data acquisition and processing system 11 .

The auxiliary system includes an evacuation system 8 and a gas pressurization system 3. The evacuation system 8 is connected to the main fluid conveying pipeline 29 through the model evacuation pipeline 32, and the evacuation system 8 is also connected to the reservoir through the annular cavity evacuation pipeline 26. The confining pressure ring cavity 15 is communicated. The vacuuming system 8 is used to vacuumize the displacement reaction system. Specifically, the vacuuming system 8 vacuumizes the reservoir confining pressure ring cavity 15 through the annular chamber vacuuming pipeline 26 , and the vacuuming system 8 vacuums the reservoir confining pressure ring cavity 15 through the vacuum vacuuming pipeline 32 of the model. The inner pores of the glass model etching model 22 are evacuated. The gas pressurization system 3 is connected to the fluid delivery main line 29 . The gas booster system 3 includes an air compressor, a gas booster pump, a gas one-way valve and a micro valve.

The temperature sensor 4 , the pressure sensor, the data acquisition and processing system 11 , the confining pressure tracking pump 17 , the gas boosting system 3 and the vacuuming system 8 are all connected to the computer 12 . Through the data acquisition and video recording system, images and videos of fluid flow in micro-nano-scale channels, as well as real-time temperature and pressure data, can be obtained, which can realize automatic integration of operation, control, and acquisition, and achieve the purpose of real-time dynamic detection of experimental progress and effects.

A plurality of the above-mentioned heating and constant temperature piston containers 2 are provided and arranged in parallel, and are respectively used to store formation oil, water, polymer and other multi-medium fluids under simulated formation temperature conditions.

The experimental method includes the following steps:

The first step is to clarify the pore-throat structure map that can reflect the deep reservoir through the preprocessing, segmentation, recovery and correction of the coring scanned image, and through the related microfluidic chip fabrication method, the simulation of the actual reservoir conditions is made. Rock-like glass etching model 22.

In the second step, the glass etching model 22 is installed in the high-pressure sealing holder 16, and the reservoir confining pressure ring cavity 15 and the glass etching model 22 are respectively evacuated through the vacuum pumping system 8, and the vacuuming time is 2h, To ensure that no air exists in the micro- and nano-scale channels of the glass etching model 22 .

The third step: inject confining pressure liquid into the confining pressure ring cavity of the reservoir through the confining pressure monitoring pipeline, and control the confining pressure through the confining pressure tracking pump 17, so that the pressure in the confining pressure ring cavity 15 of the reservoir is always higher than that of the glass etching model 22 Internal pressure 2MPa. The high-pressure magnetic circulation pump 14 is turned on, and the confining pressure liquid in the reservoir confining pressure ring cavity 15 is heated and heated through the high-temperature heating vessel 13 until the formation temperature is reached.

The fourth step is to place the glass etching model 22 under the microscope 10 , and adjust the focusing position and magnification of the microscope 10 until the data acquisition and processing system 11 can collect clear micro-nano-scale channel images inside the glass etching model 22 .

In the fifth step, the crude oil and the displacement fluid medium are respectively loaded into the heated thermostatic piston container 2, and the back pressure unit 18 is adjusted to the simulated formation pressure. First, crude oil is injected into the glass etching model 22 through the high-pressure injection pump 1 and the fluid conveying main pipeline 29, so that the glass etching model 22 is saturated with crude oil.

The sixth step is to switch the fluid in the main fluid transport pipeline 29 to the displacing fluid medium water, and carry out the water displacing oil displacing experiment. During the displacing process, real-time images are collected by the data acquisition Displacement is stopped when the remaining oil in the micro- and nano-scale channels no longer changes.

The seventh step is to switch the fluid in the main fluid delivery pipeline 29 to high-pressure gas, and carry out the high-pressure gas flooding experiment for the remaining oil through the gas booster system 3, and control the displacement mode to be continuous gas flooding or intermittent gas flooding. The data acquisition and processing system 11 acquires images in real time, and stops the displacement when the remaining oil in the micro-nano-scale channels of the glass etching model 22 no longer changes.

In the eighth step, the experiment ends after the displacement is completed, and the experimental results are obtained by analyzing the recorded data of the temperature sensor 4 and the pressure sensor and the fluid flow characteristics in the micro-nano-scale channel at the corresponding moment of the glass etching model 22 .

As a further design of the present invention, the displacement fluid medium is dyed with the same soluble dye before being loaded into the heated thermostatic piston container 2 . The purpose of dyeing with dyes is to facilitate observation and identification, and the same soluble dyes are used, that is, the dyes are only compatible with the liquid medium to be dyed, but are not compatible with the other medium to be displaced, preventing the difference between different liquids. String color.

Further, when the micro-nano pores in the glass etching model 22 are too small, such as less than 10 microns, the model 22 can be etched by kerosene-saturated glass first, so as to facilitate the smooth injection of crude oil in the later stage.

The injection speed of the above-mentioned high-pressure injection pump 1 to the crude oil and the displacement fluid medium is not higher than 0.02 mL/min.

The gas component of the above-mentioned high-pressure gas is a hydrocarbon gas mixed in any ratio of C ₁ -C ₄ . The above-mentioned gas injection flooding and water flooding process switch the displacement medium in the same way. The above-mentioned displacement fluid medium includes salinity water and high pressure gas.

Valves are provided on the confining pressure monitoring pipeline 27 , the model fluid injection pipeline 28 , the main fluid delivery pipeline 29 and the pumping pipeline 30 . Specifically, the annular cavity vacuuming pipeline 26 is connected with a first venting pipeline, and a first venting valve 39 is arranged on the first venting pipeline. Through the first venting valve 39, the reservoir can be confined to the annular cavity 15 after the experiment is completed. The confining fluid in the empties. The pumping pipeline 30 is connected with a second venting pipeline, and a second venting valve 40 is arranged on the second venting pipeline. Through the second venting valve 40, the fluid medium in the heating thermostatic piston container 2 can be vented after the experiment is completed. .

A first valve 9 is arranged on the confining pressure monitoring pipeline 27, a second valve 33 is arranged on the model fluid injection pipeline 28, and a third valve 34 is arranged on the pipeline of the low-range pressure sensor 5 connected to the main fluid conveying pipeline 29. , a fourth valve 35 is provided on the pipeline of the mid-range pressure sensor 6 connected to the main fluid delivery pipeline 29 . A fifth valve 36 , a sixth valve 37 and a seventh valve 38 are respectively provided on the branch pipeline of the pumping pipeline 30 connected to the inlet end of the heating thermostatic piston container 2 . Control valves are also arranged at the outlet end of the heating thermostatic piston container 2 . The switching of the displacement fluid medium can be controlled by the opening and closing of the relevant position valve. For example, when it is necessary to switch the crude oil and the displacing fluid medium, or to switch the displacing fluid medium to each other, the first valve 9 needs to be closed first to ensure that the confining pressure value does not change, and then the second valve 33 The fluid in the fluid delivery main line 29 and the model fluid injection line 28 is discharged.

The above-mentioned control valve can also be further connected to the computer 12 .

Further, the above method also includes the step of performing gas injection displacement through the gas booster system 3, and the gas injection displacement is the same as the method of switching the displacement medium in the sixth step of the water flooding process.

Furthermore, after the experiment, the displacement medium was replaced with petroleum ether to flush the main pipeline 29 of cleaning fluid, the model fluid injection pipeline 28 and the glass etching model 22 .

A plurality of the above-mentioned pressure sensors 4 are arranged on the main fluid conveying pipeline 29, which are respectively a low-range pressure sensor 5, a medium-range pressure sensor 6 and a high-range pressure sensor 7, which are used to monitor the simulated displacement pressure value under different injection conditions. The pressure sensors arranged on the confining pressure monitoring pipeline 27 and the model fluid production pipeline 31 are all high-range pressure sensors 7 .

The above-mentioned back pressure unit 18 includes a high-precision back pressure valve, a buffer tank and a back pressure pump. One end of the high-precision back pressure valve is connected to the glass etching model 22, the other end of the high-precision back pressure valve is connected to the buffer tank through a pipeline, and the back pressure pump is connected to the buffer tank through a pipeline. The high-precision back pressure valve adopts a sheet-type structure, which has the advantages of high adjustment sensitivity, high pressure resistance (maximum pressure 70MPa), high control precision, and light weight; the buffer tank stabilizes the pressure during the experimental displacement process and collects the output fluid. The function of pressure resistance is 70MPa.

Further, a manual bevel adjustment bracket 20 is provided at the bottom of the high-pressure sealing holder 16, and the manual bevel adjustment bracket 20 is a special bracket with a manual bevel adjustment function. The physical experiment simulation of formation inclination angle improves the operability and flexibility of the whole experimental device.

The above-mentioned high-temperature heating vessel 13 includes a sealed casing, and a heating device or the like may be arranged in the sealed casing to heat the inner space of the casing, that is, the fluid in the shell layer. A heat exchange tube is also passed through the interior of the sealed shell, and the two ends of the tube side of the heat exchange tube are respectively connected to the model fluid injection pipeline 28 and the main fluid delivery pipeline 29. The fluid passing through the heat exchange tube can communicate with the fluid in the shell. heat exchange.

Using the method of the present invention, a microscopic visualization experiment of water flooding to gas injection under high temperature and high pressure (70MPa, 150°C) was carried out, and the starting mechanism and enrichment law of remaining oil at the micro-nano scale (minimum pore throat diameter of 20 μm) were simulated. The results are shown in Figure 2 Show.

The present invention adopts the visual micro-nano-scale pore-throat model, that is, the glass etching model 22, to simulate the internal pore-throat characteristics of the actual rock, and realizes the micro-nano-scale channel of the fluid under the condition of high temperature and high pressure through the coordinated control system of reservoir temperature and pressure and the displacement reaction system. Combined with the data acquisition and video system to observe the microscopic fluid migration characteristics in the porous medium, the quantification of the remaining oil-water saturation in the microscopic pore structure during the microscopic model displacement experiment is truly realized. The judgment of the distribution and size of oil-water saturation in the oil-water saturation has important guiding significance.

The parts not mentioned in the above manner can be realized by adopting or learning from the existing technology.

The embodiments of the present invention have been described in detail above in conjunction with the accompanying drawings, but the present invention is not limited to the above-mentioned embodiments, and can also be made within the scope of knowledge possessed by those of ordinary skill in the art without departing from the purpose of the present invention. Various changes.

Claims (17)

1. A microscopic visualization experiment device for simulating fluid displacement under high temperature and high pressure conditions is characterized in that it includes a reservoir temperature and pressure coordinated control system, a displacement reaction system, a data acquisition and video recording system and an auxiliary system;

   The reservoir temperature and pressure coordinated control system includes a high-pressure sealing holder (16), a sapphire window (23) for easy observation is arranged on the high-pressure sealing holder (16), and a sapphire window (23) for easy observation is arranged on the high-pressure sealing holder (16). A reservoir confining pressure ring cavity (15) is formed inside; the reservoir confining pressure ring cavity (15) is connected to the shell inlet of the high temperature heating vessel (13) through a fluid heating output pipeline (24), and the high temperature heating vessel (13) ) shell outlet is communicated with the reservoir confining pressure ring cavity (15) through the fluid heating input pipe (25), and a high-pressure magnetic circulation pump (14) is arranged on the fluid heating input pipe (25); The pressure ring cavity (15) is connected with the confining pressure monitoring pipeline (27), and a confining pressure tracking pump (17) is arranged on the confining pressure monitoring pipeline (27);

   The displacement reaction system includes a high-pressure injection pump (1), a heated thermostatic piston container (2), a glass etching model (22) and a back pressure unit (18), and the glass etching model (22) is placed in a high-pressure sealing clamp. Inside the device (16), an injection end is provided at one end of the glass etching model (22), and the injection end is connected with one end of the model fluid injection pipe (28), and the other end of the model fluid injection pipe (28) is connected to the high temperature. The pipe layer outlet of the heating container (13) is connected, the pipe layer inlet of the high temperature heating container (13) is connected with the fluid conveying main pipeline (29), and the fluid conveying main pipeline (29) is connected with the outlet of the heating thermostatic piston container (2). The ends are connected, and the inlet end of the heating thermostatic piston container (2) is connected to the high pressure injection pump (1) through the pumping pipeline (30); the other end of the glass etching model (22) is provided with a production end, and the production end passes through The model fluid production pipeline (31) is connected to the back pressure unit (18), and a condenser (19) is arranged on the model fluid production pipeline (31);

   The data acquisition and video recording system includes a temperature sensor (4), a pressure sensor, a microscope (10), a data acquisition and processing system (11) and a computer (12), and the temperature sensor (4) is respectively disposed in a heating thermostatic piston container ( 2) and the high temperature heating vessel (13), the pressure sensors are respectively arranged on the main fluid conveying pipeline (29), the confining pressure monitoring pipeline (27) and the model fluid extraction pipeline (31); the microscope (10) is arranged on the opposite side At the position of the sapphire viewing window (23), the data acquisition and processing system (11) is arranged at the observation end of the eyepiece of the microscope (10);

   The auxiliary system includes an evacuation system (8) and a gas pressurization system (3). The evacuation system (8) is connected to the main fluid conveying pipeline (29) through a model evacuation pipeline (3), and the evacuation system (8) ) is also communicated with the reservoir confining pressure annular cavity (15) through the annular cavity vacuuming pipeline (26); the gas booster system (3) is connected with the fluid conveying main pipeline (29);

   The temperature sensor (4), pressure sensor, data acquisition and processing system (11), confining pressure tracking pump (17), gas boosting system (3) and vacuuming system (8) are all connected with the computer (12).
2. The microscopic visualization experimental device for simulating fluid displacement under high temperature and high pressure conditions according to claim 1, characterized in that, a plurality of said heating thermostatic piston containers (2) are provided and arranged in parallel.
3. The microscopic visualization experimental device for simulating fluid displacement under high temperature and high pressure conditions according to claim 1, wherein a plurality of said pressure sensors are arranged on the main fluid conveying pipeline (29), and they are respectively low-range pressure sensors (5). ), a medium-range pressure sensor (6) and a high-range pressure sensor (7), and the pressure sensors arranged on the confining pressure monitoring pipeline (7) and the model fluid production pipeline (31) are all high-range pressure sensors (7).
4. The microscopic visualization experimental device for simulating fluid displacement under high temperature and high pressure conditions according to claim 1, wherein the back pressure unit (18) comprises a high precision back pressure valve, a buffer tank and a back pressure pump.
5. The microscopic visualization experiment device for simulating fluid displacement under high temperature and high pressure conditions according to claim 1, characterized in that, the annular cavity vacuuming pipeline (26) is connected with a first venting pipeline, and a first venting pipeline is arranged on the first venting pipeline There is a first venting valve (39); the pumping pipeline (30) is connected with a second venting pipeline, and a second venting valve (40) is arranged on the second venting pipeline.
6. The microscopic visualization experimental device for simulating fluid displacement under high temperature and high pressure conditions according to claim 1, wherein a first valve (9) is provided on the confining pressure monitoring pipeline (27), and a model fluid injection pipeline (28) is provided on the confining pressure monitoring pipeline (27). ) is provided with a second valve (33), a third valve (34) is provided on the pipeline of the low-range pressure sensor (5) connected to the main fluid delivery pipeline (29), and a third valve (34) is provided on the pipeline connected to the main fluid delivery pipeline (29) A fourth valve (35) is provided on the pipeline of the mid-range pressure sensor (6); a fifth valve (36), a sixth valve (36), a sixth valve (36), a fifth valve (36) and a sixth valve (37) and seventh valve (38).
7. The microscopic visualization experiment device for simulating fluid displacement under high temperature and high pressure conditions according to claim 1, characterized in that a manual bevel angle adjusting bracket (20) is provided at the bottom of the high pressure sealing holder (16).
8. A microscopic visualization experiment method for high temperature and high pressure gas flooding oil in a deep oil reservoir, characterized in that a microscopic visualization experimental device for high temperature and high pressure gas flooding in a deep oil reservoir is adopted, and the microscopic visualization experimental device for high temperature and high pressure gas flooding in a deep oil reservoir comprises a reservoir Temperature and pressure coordinated control system, displacement reaction system, data acquisition and video recording system and auxiliary system;

   The reservoir temperature and pressure coordinated control system includes a high-pressure sealing holder (16), a sapphire window (23) for easy observation is arranged on the high-pressure sealing holder (16), and a sapphire window (23) for easy observation is arranged on the high-pressure sealing holder (16). A reservoir confining pressure ring cavity (15) is formed inside; the reservoir confining pressure ring cavity (15) is connected to the shell inlet of the high temperature heating vessel (13) through a fluid heating output pipeline (24), and the high temperature heating vessel (13) ) shell outlet is communicated with the reservoir confining pressure ring cavity (15) through the fluid heating input pipe (25), and a high-pressure magnetic circulation pump (14) is arranged on the fluid heating input pipe (25); The pressure ring cavity (15) is connected with the confining pressure monitoring pipeline (27), and a confining pressure tracking pump (17) is arranged on the confining pressure monitoring pipeline (27);

   The displacement reaction system includes a high-pressure injection pump (1), a heated thermostatic piston container (2), a glass etching model (22) and a back pressure unit (18), and the glass etching model (22) is placed in a high-pressure sealing clamp. Inside the device (16), an injection end is provided at one end of the glass etching model (22), and the injection end is connected with one end of the model fluid injection pipe (28), and the other end of the model fluid injection pipe (28) is connected to the high temperature. The pipe layer outlet of the heating container (13) is connected, the pipe layer inlet of the high temperature heating container (13) is connected with the fluid conveying main pipeline (29), and the fluid conveying main pipeline (29) is connected with the outlet of the heating thermostatic piston container (2). The ends are connected, and the inlet end of the heating thermostatic piston container (2) is connected to the high pressure injection pump (1) through the pumping pipeline (30); the other end of the glass etching model (22) is provided with a production end, and the production end passes through The model fluid production pipeline (31) is connected to the back pressure unit (18), and a condenser (19) is arranged on the model fluid production pipeline (31);

   The data acquisition and video recording system includes a temperature sensor (4), a pressure sensor, a microscope (10), a data acquisition and processing system (11) and a computer (12), and the temperature sensor (4) is respectively disposed in a heating thermostatic piston container ( 2) and the high temperature heating vessel (13), the pressure sensors are respectively arranged on the main fluid conveying pipeline (29), the confining pressure monitoring pipeline (27) and the model fluid extraction pipeline (31); the microscope (10) is arranged on the opposite side At the position of the sapphire viewing window (23), the data acquisition and processing system (11) is arranged at the observation end of the eyepiece of the microscope (10);

   The auxiliary system includes an evacuation system (8) and a gas pressurization system (3). The evacuation system (8) is connected to the main fluid conveying pipeline (29) through a model evacuation pipeline (3), and the evacuation system (8) ) is also communicated with the reservoir confining pressure annular cavity (15) through the annular cavity vacuuming pipeline (26); the gas booster system (3) is connected with the fluid conveying main pipeline (29);

   The temperature sensor (4), the pressure sensor, the data acquisition and processing system (11), the confining pressure tracking pump (17), the gas boosting system (3) and the vacuuming system (8) are all connected with the computer (12);

   The experimental method includes the following steps:

   The first step is to make a glass etching model for simulating rock samples under actual reservoir conditions (22);

   The first step is to install the glass etching model (22) in the high-pressure sealing holder (16), and carry out the operation on the reservoir confining pressure ring cavity (15) and the glass etching model (22) through the vacuum pumping system (8). Vacuum;

   In the second step, the confining pressure liquid is injected into the reservoir confining pressure annular cavity (15) through the confining pressure monitoring pipeline (27), and the confining pressure is controlled by the confining pressure tracking pump (17), so that the reservoir confining pressure annular cavity (15) is controlled. ), the pressure is higher than the internal pressure of the glass etching model (22); the high-pressure magnetic circulation pump (14) is turned on, and the confining pressure liquid in the reservoir confining pressure ring cavity (15) is heated and heated by the high-temperature heating vessel (13) until the temperature is increased. formation temperature;

   The third step is to place the glass etching model (22) under the microscope (10), and adjust the focusing position and magnification of the microscope (10) until the data acquisition and processing system (11) can collect a clear glass etching model (22). ) internal micro- and nano-scale channel images;

   In the fourth step, the crude oil and the displacement fluid medium are respectively loaded into the heating thermostatic piston container (2), and the back pressure unit (18) is adjusted to the simulated formation pressure; 29) inject crude oil into the glass etching model (22), so that the glass etching model (22) is saturated with crude oil;

   The fifth step is to switch the fluid in the main fluid conveying pipeline (29) to the displacing fluid medium water, and carry out the water displacing oil displacing experiment. When the remaining oil in the micro-nano-scale channel of (22) no longer changes, the displacement is stopped;

   The sixth step is to switch the fluid in the main fluid transport pipeline (29) to high-pressure gas, and carry out the high-pressure gas flooding experiment for the remaining oil through the gas booster system, and control the displacement mode to be continuous gas flooding or intermittent gas flooding. Real-time images are collected by the data collection and processing system (11), and the displacement is stopped when the remaining oil in the micro- and nano-scale channels of the glass etching model (22) no longer changes;

   In the seventh step, the experiment ends after the displacement is completed, and the experimental results are obtained by analyzing the recorded data of the temperature sensor (4) and the pressure sensor and the fluid flow characteristics in the micro-nano-scale channel at the corresponding moment of the glass etching model (22).
9. A microscopic visualization experiment method for high temperature and high pressure gas flooding in deep oil reservoirs according to claim 8, characterized in that: through preprocessing, segmentation, restoration and correction of the scanned images of rock sample cores, it can clearly reflect the deep oil reservoirs A pore-throat structure diagram of reservoir characteristics is obtained, and a glass etching model (22) is prepared by a microfluidic chip fabrication method.
10. A microscopic visualization experiment method for high temperature and high pressure gas flooding in deep oil reservoirs according to claim 8, wherein the confining pressure is controlled by the confining pressure tracking pump, so that the pressure in the confining pressure ring cavity of the reservoir is higher than that of the glass etching model Internal pressure 2MPa.
11. The microscopic visualization experiment method for high temperature and high pressure gas flooding in deep oil reservoirs according to claim 8, wherein the displacement fluid medium is dyed with the same soluble dye before being loaded into the heating thermostatic piston container (2). .
12. The microscopic visualization experiment method for high-temperature and high-pressure gas flooding in deep oil reservoirs according to claim 8, characterized in that, when the micro-nano pores in the glass etching model (22) are smaller than 10 microns, before injecting crude oil, first The pattern (22) is etched through kerosene-saturated glass.
13. The method for microscopic visualization experiment of high temperature and high pressure gas flooding oil in a deep oil reservoir according to claim 8, characterized in that the injection speed of the high pressure injection pump (1) to the crude oil and the displacement fluid medium is not higher than 0.02 mL /min.
14. A microscopic visualization experiment method for high temperature and high pressure gas flooding oil in a deep oil reservoir according to claim 8, characterized in that, a first valve (9) is provided on the confining pressure monitoring pipeline (27), and a model fluid injection pipeline ( 28) is provided with a second valve (33), and the second valve (33) is a three-way valve; when it is necessary to switch the crude oil and the displacement fluid medium, or when the displacement fluid medium is switched between each other, it is necessary to The first valve (9) is closed first, and then the fluid in the main fluid delivery pipeline (29) and the model fluid injection pipeline (28) is discharged through the second valve (33).
15. The microscopic visualization experimental method for oil displacement by high temperature and high pressure gas in deep oil reservoirs according to claim 8, wherein the gas component of the high pressure gas is hydrocarbon gas mixed with C ₁ -C ₄ in any proportion.
16. A method for microscopic visualization experiment of high temperature and high pressure gas flooding in deep oil reservoir according to claim 8, characterized in that: after the experiment is finished, the displacement medium is replaced with petroleum ether for flushing and cleaning the fluid conveying main pipeline (29), model fluid Injection line (28) and glass etch pattern (22).
17. A microscopic visualization experiment method for high temperature and high pressure gas flooding in deep oil reservoirs according to claim 8, characterized in that, the annular cavity vacuuming pipeline (26) is connected with a first venting pipeline, and the first venting pipeline is connected to the first venting pipeline. A first venting valve (39) is provided; a second venting pipeline is connected to the pumping pipeline (30), and a second venting valve (40) is arranged on the second venting pipeline; (39) The fluid in the reservoir confining pressure ring cavity (15) is discharged, and the fluid in the heated thermostatic piston container (2) is discharged through the second vent valve (40).

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