Carbonate reservoir multi-scale process simulation method and device

Abstract

The invention discloses a carbonate reservoir multi-scale process simulation method and device. The device comprises a jacketed simulation cylinder, a slide, a sapphire negative plate, a sapphire cover plate, a pressure chamber and a clamping device, a mounting groove, and an injection groove I, an injection groove II, an injection groove III and an extraction groove which are communicated with the mounting groove are formed in the sapphire substrate; the slide is mounted in the mounting groove; fluid capsules are respectively placed in the injection groove I, the injection groove II and the injection groove III; the jacket type simulation cylinder is provided with a temperature control cavity and a pressure cavity; the sapphire cover plate covers the sapphire bottom plate, and the sapphire cover plate and the sapphire bottom plate are mounted in the clamping device together; and the clamping device is mounted in the pressure chamber. The invention mainly aims at solving the problems of micromodel manufacturing and microcosmic devices in the process of researching the water-oil displacement and chemical agent oil displacement rules of the carbonate reservoir from a microcosmic angle indoors, and providing technical support for researching the water-oil displacement and chemical agent oil displacement mechanisms of the carbonate reservoir indoors.

Description

Technical Field

[0001] The invention relates to a multi-scale process simulation method and device for a carbonate reservoir, belonging to the technical field of oil and gas field development. Background Art

[0002] Carbonate reservoirs are widely distributed worldwide, accounting for 60% of discovered oil reserves, posing enormous development potential. Carbonate reservoirs are categorized into fracture-cavity, fracture-type, and porous-type carbonate reservoirs. These reservoirs exhibit complex mineralogy, matrix pore structure, and rock surface properties, resulting in high heterogeneity. Initially, reservoirs are primarily developed through natural energy depletion, while later, horizontal well water injection is often employed. Long-term water injection leads to significant negative impacts on reservoir water flow pathways, severe ineffective water circulation, and a sharp increase in reservoir water cut. There is an urgent need to find effective methods to control high water cuts in reservoirs and support the development and stable production of carbonate reservoirs. Chemical flooding EOR technology has achieved significant results in increasing oil production and reducing water loss in sandstone oilfields such as Daqing, Shengli, Dagang, Henan, Liaohe and Bohai. However, in carbonate reservoirs, the complex reservoir environment has led to slow progress in chemical flooding EOR technology, and the mechanism of chemical flooding EOR is unclear. Therefore, understanding the microscopic mechanism of chemical agents in the pore structure of carbonate reservoirs is of great significance for improving crude oil recovery.

[0003] Currently, research on the microscopic mechanisms of chemical flooding for enhanced oil recovery has largely focused on sandstone reservoirs, primarily using glass etching or real sandstone thin-section models for microscopic flooding experiments. However, research on carbonate rocks is relatively limited. Compared to sandstone reservoirs, carbonate rocks are sedimentary rocks primarily composed of carbonate minerals. The main types are limestone composed of calcite or aragonite, and dolomite composed of the mineral dolomite. Sandstone, on the other hand, is primarily composed of quartz grains cemented with various minerals, and the two types have significantly different properties.

[0004] The method described in publication number CN205063923U of embedding a carbonate rock core slice in the inner cavity of a glass slide has a high core sampling cost. The core slice embedded in the glass slide has low transparency, which is not conducive to observing the mechanism of chemical agent activation of residual oil during the experiment. In addition, the glass slide is easily broken when the combined model is subjected to uneven force.

[0005] The carbonate rock micro-displacement model described in publication number CN112598986A involves cutting calcite into crystal slices, immersing the slices in a wax solution to coat them with a wax coating, sanding them, and then using a CO2 laser to project a pattern onto the wax coating. This process is then replicated and acid-etched. During this modeling process, calcite is susceptible to cleavage and can easily crack or break along its cleavage direction under external forces. Calcite glass slides with good optical transparency and a smooth surface are difficult to produce.

[0006] The micromodels described in publications CN109827884A, CN114088919A, CN108986627A, and CN 105332686A, among others, contain only a single liquid inlet channel. During experiments, after saturation with oil, the model channel is completely filled with crude oil. During water flooding and chemical flooding, the oil in the channel continuously enters the model, affecting the experimental observations and recovery of crude oil during water or chemical flooding.

[0007] Publication Nos. CN112730196A and CN118010587A both use rubber sealing rings between glass slides to ensure the sealing of the glass slides. However, the rubber sealing rings are prone to aging under high temperature and high pressure. Summary of the Invention

[0008] The purpose of the present invention is to address the problems existing in the prior art and provide a multi-scale process simulation method and device for carbonate oil reservoirs. The present invention is mainly to solve the problem of micro-model production and micro-device production in the process of indoor microscopic research on the laws of water flooding and chemical flooding in carbonate oil reservoirs and the utilization of residual oil, and to provide technical support for indoor research on the mechanisms of water flooding and chemical flooding in carbonate oil reservoirs.

[0009] The present invention solves the above technical problems and provides a technical solution: a method and device for simulating multi-scale processes in carbonate reservoirs, comprising a jacketed simulation cylinder, a glass slide, a sapphire bottom plate, a sapphire cover plate, a pressure chamber, and a clamping device;

[0010] The sapphire film is provided with a mounting groove and injection grooves I, II, III, and extraction grooves communicating with the mounting groove; the glass slide is installed in the mounting groove; fluid capsules 42 are placed in the injection grooves I, II, and III;

[0011] The clamping device is provided with an injection pipeline, an injection pipeline, an injection channel, and a production pipeline which are connected to the injection tank I, the injection tank II, the injection tank III, and the production tank in sequence. The size of the injection tank is length × width × height = 10mm × 5mm × 3mm;

[0012] The jacketed simulation cylinder has a temperature control chamber and a pressure chamber; the sapphire cover plate covers the sapphire base plate and is installed together in a clamping device; the clamping device is installed in the pressure chamber.

[0013] A further technical solution is that the glass slide is provided with a rock slice, an injection channel I, an injection channel II, an injection channel III, an extraction channel, and a fluid chamber; the fluid chambers are respectively located at the left and right ends of the rock slice; the injection channel I, injection channel II, and injection channel III are all connected to the fluid chamber on the left side of the rock slice, and the extraction channel is connected to the fluid chamber on the right side of the rock slice.

[0014] A further technical solution is that the clamping device includes a clamping upper part and a clamping lower part that are threadedly connected.

[0015] A further technical solution is that both the sapphire bottom film and the sapphire cover film are provided with a tetrafluoroethylene gasket.

[0016] A further technical solution is that a sapphire observation window and a sapphire light-transmitting window are respectively provided at the upper and lower ends of the jacketed simulation cylinder.

[0017] A further technical solution is that the jacketed simulation cylinder is provided with a fluid inlet and a fluid outlet communicating with the temperature control chamber, and a gas inlet and a gas outlet communicating with the pressure chamber.

[0018] A further technical solution is that a pressure sensor and a temperature sensor are provided in the jacketed simulation cylinder.

[0019] A further technical solution is that the injection pipeline, injection pipeline, injection channel and production pipeline are respectively provided with injection valve I, injection valve II, injection valve III and production valve.

[0020] A multi-scale process simulation method for carbonate reservoirs specifically comprises the following steps:

[0021] Step S10: model design;

[0022] The binary graph of the rock pore throat structure is extracted based on the thin slices of cast bodies sampled from the real carbonate core in the oil field, and the injection channel I, injection channel II, injection channel III, and production channel are drawn at both ends of the rock pore throat structure. The width of the injection channel should be greater than or equal to 1.5 times the width of the production channel; the fluid storage cavity is drawn 1 mm away from the injection channel and the production channel to the rock pore throat structure, and the fluid chamber size is length × width = 7 mm × 1 mm; the materials used for the fluid capsule 42 placed inside the injection grooves 10, 11, and 12 include but are not limited to fluororubber and polytetrafluoroethylene PTFE composites, silicone rubber-based composite materials, acid and alkali resistance, temperature resistance of 200°C, pressure resistance of 30 MPa, acid and alkali resistance, temperature resistance of 200°C, pressure resistance of 30 MPa and high elasticity, and the size is 5 mm in diameter × 10 mm in length;

[0023] The connections between the fluid capsule 42 and the injection channels 3, 4, and 5 are sealed with sealing rings 9, and the connections between the fluid capsule 42 and the one-way valve 44 are sealed with sealing rings 45 to ensure good sealing of the connections. The sealing rings 9 and 45 used are made of perfluororubber and are resistant to acid and alkali corrosion and high temperature and high pressure.

[0024] Step S20: making and cleaning glass slides;

[0025] Select colorless, transparent, and glossy calcite, and cut it into cylindrical calcite sheets along its cleavage direction using a precision cutting machine;

[0026] Embed the cut cylindrical calcite piece into a sapphire plate with a groove in the middle. Use a high-precision polishing machine at 500 rpm to polish the protruding part of the calcite piece embedded in the sapphire plate until it is flat and smooth. The dimensions of the polished calcite glass slide are 27 mm in diameter × 3 mm in thickness. The surface roughness of the calcite and sapphire after polishing is ≤ 500 nm.

[0027] Place the calcite glass slide in a mixture of toluene and methanol (toluene: methanol = 1:1) and sonicate for 2 h, then rinse repeatedly with deionized water for at least 5 times, and finally dry at room temperature in a dust-free box;

[0028] Step S30, measuring the initial wettability of the glass slide and etching;

[0029] According to the wettability of real carbonate oil reservoirs, glass slides with different calcite contents were selected to measure whether the initial wettability of the calcite glass slides was consistent with the wettability of the reservoir rock;

[0030] Then, pattern etching is performed. During the etching process, carbonate reservoirs are classified and etched with different acid solutions. During the acid etching, carbonate reservoirs are classified and etched. Fracture-type and fracture-type carbonate reservoirs have larger pore channels and contain fractures and pores, and are etched with 10% hydrochloric acid. Porous carbonate reservoirs have smaller pore channels and are etched with 4% hydrochloric acid + 8% citric acid. The ratio of hydrochloric acid to citric acid is adjusted according to the calcite content of the glass slide. The adjustment range of the hydrochloric acid ratio is 5% to 20%, and the adjustment range of the citric acid ratio is 80% to 95%.

[0031] Step S40: placing the glass slide in a carbonate reservoir multi-scale process simulation device;

[0032] Step S50: Connect the outlet of the XHGD external circulation high and low temperature integrated thermostatic bath to the fluid inlet, connect the inlet of the XHGD external circulation high and low temperature integrated thermostatic bath to the fluid outlet, so that the fluid circulates in the temperature control chamber, set the temperature of the XHGD external circulation high and low temperature integrated thermostatic bath to the reservoir temperature of 105°C, heat the entire device, and monitor the temperature in real time with a temperature sensor;

[0033] Step S60: Close the gas outlet and connect nitrogen to the gas inlet, so that the nitrogen enters the pressure chamber to pressurize the entire glass slide. The pressure is monitored and controlled by the pressure sensor and is set to the reservoir formation pressure of 23 MPa.

[0034] Step S70: Connect the vacuum pump to the injection valve III, close the injection valve I, injection valve II, and the extraction valve, turn on the vacuum pump, and evacuate for 60 minutes;

[0035] Step S80: performing an oil displacement experiment test;

[0036] Step S90: Compare the type and content of the remaining oil after the water flooding of the glass slide with that of the actual reservoir after the water flooding. If the error is less than 10%, it is considered that the etched calcite glass slide can fully simulate the reservoir. If it is greater than 10%, it is necessary to re-etch according to step S30.

[0037] Step S100, cleaning the tested glass slide and measuring wettability;

[0038] The experimental oil on the surface of the glass slide was cleaned with anhydrous ethanol solution, and the slide was placed in a mixture of toluene and methanol (1:1) and ultrasonicated for 2 hours. The surface of the glass slide was rinsed with deionized water and dried in an oven. The slide was then immersed in crude oil and aged for 7 days. The contact angle of the oil-water-glass slide system was measured again to determine the oil wettability W of the slide. h , the oil wettability W measured after the experiment h Compared with the oil wettability W measured before the experiment q Not exceeding 3%.

[0039] A further technical solution is that the specific process of step S80 includes:

[0040] Step S81: Connect the micro-injection pump to injection valve I, close injection valves II and III, open the extraction valve, and inject hydraulic oil into injection tank I to squeeze the fluid capsule so that the oil quickly enters the pore throats. Observe the saturated oil in the model pore throats through the sapphire observation window under a microscope. When the model pore throats are full of oil, close the micro-injection pump.

[0041] Step S82: Connect the micro-injection pump to injection valve I, close the production valve and injection valve III, and open injection valve II. Turn the entire device sideways, inject hydraulic oil into injection tank II, squeeze the fluid capsule to allow formation water to enter the channel, and clean the channel. Observe through the sapphire observation window under a microscope to see if the oil in the fluid chamber has been flushed clean. When the oil has been flushed clean, close the micro-injection pump.

[0042] Step S83: Place the entire device at an oil reservoir temperature of 105° C. for 24 hours;

[0043] Step S84: Connect the micro-injection pump to injection valve III, close injection valve I and injection valve II, open the production valve, and use a micro-meter to measure the produced fluid at the production valve; allow hydraulic oil to enter injection tank II to squeeze the fluid capsule so that formation water enters the pore throats of the glass slide, observe the water-to-oil displacement process through the sapphire observation window under a microscope, and use the image acquisition system to collect images of the displacement process. When the oil in the pore throats of the model is not being used, the experiment is terminated, the XHGD external circulation high and low temperature integrated constant temperature bath is closed, the fluid in the temperature control chamber is released from the fluid outlet, the gas outlet is opened, the pressure in the pressure chamber is unloaded, and the model is disassembled to remove the glass slide.

[0044] The present invention has the following beneficial effects:

[0045] 1. The present invention uses calcite glass slide etching to simulate carbonate oil reservoirs. Glass slides with different calcite contents are selected to simulate the wettability of carbonate oil reservoirs. After etching, the wettability of the glass slides is measured and matched with the wettability of the reservoir rock. Using calcite glass slide etching is fast, simple, and reusable, saving time and maintaining consistency with actual oil reservoirs.

[0046] 2. In the process of glass slide etching, the present invention classifies the carbonate reservoirs into different types of acid etching when etching the pores. The pores of fracture-type and fracture-type carbonate reservoirs are relatively large and contain fractures and pores, so they are etched with 10% hydrochloric acid. The pores of porous carbonate reservoirs are relatively small and they are etched with 4% hydrochloric acid + 8% citric acid. The ratio of hydrochloric acid to citric acid can be adjusted according to the different calcite content of the glass slide, thereby increasing the success rate of glass slide etching and being applicable to different types of carbonate reservoirs.

[0047] 3. The present invention embeds a calcite glass slide into a sapphire glass for grinding and polishing, thereby increasing the compressive resistance of the calcite and preventing cleavage and breakage of the calcite during the grinding and polishing process. The grinding and polishing process is fast and simple, highly operable, and the polishing thickness is controllable.

[0048] 4. The present invention adopts the method of adding fluid capsules into the sapphire film. When assembling the model, each experimental fluid can be placed in the fluid capsule in advance. The fluid capsule can be used multiple times, which saves the time of the fluid flowing through the channel at a low flow rate during the experiment, saving time and cost.

[0049] 5. The present invention adds a pre-filled groove on the sapphire film, in which a distributed optical fiber can be embedded. The OSI-D dynamic distributed optical fiber sensing system is used to transmit and receive signals. The oil-water content and oil-water distribution in the model channel at any time can be measured, and the experimental phenomena can be digitized, thereby improving the accuracy and reliability of the experimental data.

[0050] 6. The clamping device of the present invention uses a high temperature, high pressure and corrosion resistant PTFE gasket placed on the sapphire cover sheet and under the sapphire bottom sheet. The clamping device is fixed with threads at the top and bottom. The clamping device is placed in a pressure chamber and pressurized and sealed. This method has a good sealing effect, does not damage the glass slide, and is simple and convenient to operate.

[0051] 7. After the experiment of the present invention, the calcite glass slide is not damaged. The calcite glass slide is cleaned and aged in crude oil immersed in the calcite glass slide at the reservoir temperature and pressure to restore the wettability of the reservoir. The experiment can be continued by changing a single variable and using the same glass slide to carry out the experiment, thereby ensuring the accuracy and reliability of the experiment and saving the cost and time of glass slide etching.

[0052] 8. This method compares the type and content of remaining oil in the pore channels of the glass slide after waterflooding with the type and content of remaining oil in the pore channels of real reservoir cores after waterflooding. Only when the error is less than 10% can the etched glass slide be considered consistent with the reservoir physical properties, indicating that the reservoir can be fully simulated. This further improves the credibility and accuracy of laboratory research on carbonate oil reservoirs. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 This is the pore throat extraction diagram of the casting thin section of the present invention;

[0054] Figure 2 This is a design drawing of the calcite glass slide model of the present invention;

[0055] Figure 3 This is a picture of a calcite glass slide before being ground and polished according to the present invention;

[0056] Figure 4 This is a picture of a calcite glass slide after being polished according to the present invention;

[0057] Figure 5 This is a diagram after etching the model of the present invention;

[0058] Figure 6 A diagram of a slide clamping device according to the present invention;

[0059] Figure 7 is a cross-sectional view of the slide clamping device of the present invention;

[0060] Figure 8 This is a diagram of the experimental device of the present invention;

[0061] Figure 9 is a schematic diagram of the fluid capsule of the present invention;

[0062] Figure 10 This is a pore throat extraction diagram of a porous carbonate rock casting thin section of the present invention.

[0063] Shown in the figure: 1- rock, 2- pore throat structure, 3- injection channel I, 4- injection channel II, 5- injection channel III, 6- production channel, 7- glass slide, 8- fluid chamber, 9- sealing ring, 10- injection tank I, 11- injection tank II, 12- injection tank III, 13- production channel, 14- pre-filling tank, 15- injection pipeline I, 16- injection pipeline II, 17- injection pipeline III, 18- production pipeline, 19- sapphire film, 20- sapphire cover, 21- clamping top, 22- thread, 23- PTFE gasket , 24-clamping lower part, 25-sapphire observation window, 26-gas inlet, 27-gas outlet, 28-pressure sensor, 29-temperature sensor, 30-injection valve I, 31-injection valve II, 32-injection valve III, 33-extraction valve, 34-temperature control chamber, 35-fluid inlet, 36-fluid outlet, 37-pressure chamber, 38-clamping device, 39-sapphire light-transmitting window, 40-fixed bracket, 41-elastic groove, 42-fluid capsule, 43-experimental fluid storage chamber, 44-one-way valve, 45-sealing ring. DETAILED DESCRIPTION

[0064] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described are only part of the embodiments of the invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0065] like Figure 2-Figure 9 As shown, a multi-scale process simulation device for carbonate reservoirs of the present invention includes a jacketed simulation cylinder, a glass slide 7, a sapphire bottom plate 19, a sapphire cover plate 20, a pressure chamber 37, and a clamping device 38;

[0066] The sapphire film 19 is provided with a mounting groove and an injection groove I 10, an injection groove II 11, an injection groove III 12, and a collection groove 13 connected to the mounting groove; the glass slide 7 is installed in the mounting groove; the injection groove I 10, the injection groove II 11, and the injection groove III 12 are respectively provided with a fluid capsule 42;

[0067] The clamping device 38 is provided with an injection line 15, an injection line 16, an injection channel 17, and a production line 18 which are connected to the injection tank I 10, the injection tank II 11, the injection tank III 12, and the production tank 13 in sequence;

[0068] The jacketed simulation cylinder has a temperature control chamber 34 and a pressure chamber 37 ; the sapphire cover plate 20 covers the sapphire bottom plate 19 and is installed together in a clamping device 38 ; the clamping device 38 is installed in the pressure chamber 37 through a fixing bracket 40 .

[0069] like Figure 9As shown, the fluid capsule 42 includes an experimental fluid storage chamber 43 and an elastic groove 41, a one-way valve 44, and a sealing ring 45 arranged on the left side of the experimental fluid storage chamber 43;

[0070] like Figure 2 and Figure 5 As shown, in this embodiment, the glass slide 7 is provided with a rock slice 1, an injection channel I3, an injection channel II4, an injection channel III5, a production channel 6, and a fluid chamber 8; the fluid reservoir chamber 8 is respectively located at the left and right ends of the rock slice 1; the injection channel I3, the injection channel II4, and the injection channel III5 are all connected to the fluid chamber 8 on the left side of the rock slice 1, and the production channel 6 is connected to the fluid chamber 8 on the right side of the rock slice 1.

[0071] like Figure 8 As shown, in this embodiment, in order to improve the sealing performance, the clamping device 38 includes a threaded clamping upper part 21 and a clamping lower part 24, and the sapphire bottom film 19 and the sapphire cover film 20 are both provided with a polytetrafluoroethylene gasket 23.

[0072] like Figure 8 As shown, in this embodiment, in order to facilitate real-time observation of the experimental conditions of the device, a sapphire observation window 25 and a sapphire light-transmitting window 39 are respectively provided at the upper and lower ends of the jacketed simulation cylinder.

[0073] like Figure 8 As shown, in this embodiment, the jacketed simulation cylinder is provided with a fluid inlet 35 and a fluid outlet 36 communicating with the temperature control chamber 34 , and a gas inlet 26 and a gas outlet 27 communicating with the pressure chamber 37 .

[0074] like Figure 8 As shown, in this embodiment, in order to monitor the temperature and pressure in the device in real time, a preferred implementation is that a pressure sensor 28 and a temperature sensor 29 are provided in the jacketed simulation cylinder.

[0075] like Figure 8 As shown, in this embodiment, in order to better control the opening and closing of the pipelines, the injection pipeline 15, the injection pipeline 16, the injection channel 17, and the production pipeline 18 are respectively provided with an injection valve I 30, an injection valve II 31, an injection valve III 32, and a production valve 33.

[0076] Example 1

[0077] An oil field in the Middle East is a fracture-cavity carbonate reservoir with an average porosity of 27.4%, large pore volume, reservoir temperature of 87°C, and reservoir pressure of 10 MPa.

[0078] A multi-scale process simulation method for carbonate reservoirs specifically comprises the following steps:

[0079] Step S10: model design;

[0080] Skeleton extraction: Designed and extracted based on the real core casting thin section map of the oil field reservoir Figure 1 The real core pore structure is extracted using PS editing software. Figure 1 Fill Hole 2 in the image with white. After filling, select all white areas and invert the color. Fill Rock 1 with black. Modify the connection between Hole and Rock, remove the large jagged edges of Hole, and make the Hole structure curve smooth. Porosity is the pore volume of rock V. p and the rock surface volume V b The model is an etching model, and its etching depth is constant. Therefore, the calculation process is converted into the calculation of the corresponding area ratio. According to the pixel value of hole 2 20880 and Figure 1 The total pixel value is 74790, which can be calculated as Figure 1 The structural porosity is 27.92%, which is close to the average porosity of the reservoir.

[0081] Hole structure in rock Figure 1 Injection channel 3Ⅰ, injection channel Ⅱ4, injection channel Ⅲ5, and production channel 6 are drawn at both ends. A fluid chamber 8 is drawn 1 mm away from the rock pore structure between the injection channel Ⅲ5 and the production channel 6. The size of the fluid chamber is length × width = 7 mm × 1 mm.

[0082] The materials used for placing the fluid capsule 42 in the injection grooves 10, 11, and 12 include but are not limited to fluororubber and polytetrafluoroethylene PTFE composites, and silicone rubber-based composite materials. They are acid and alkali resistant, temperature resistant to 200°C, pressure resistant to 30MPa, and have high elasticity. The size of the fluid capsule is 5mm in diameter × 10mm in length; the connection between the fluid capsule 42 and the injection channels 3, 4, and 5 is sealed with a sealing ring 9, and the connection between the fluid capsule 42 and the one-way valve 44 is sealed with a sealing ring 45 to ensure good sealing of the connection. The sealing rings 9 and 45 used are made of perfluororubber and are resistant to acid and alkali corrosion and resistant to high temperature and high pressure.

[0083] Step S20: making and cleaning glass slides;

[0084] Calcite slide preparation: Colorless, transparent, and glossy calcite was selected and cut along its cleavage direction using a Secotom-60 precision cutter into cylindrical calcite slides measuring 27 mm in diameter and 6 mm in thickness. Sapphire film 19 was cut into cylinders measuring 35 mm in diameter and 10 mm in thickness, with a central groove measuring 27 mm by 3 mm. The cut calcite slide was placed into the central groove of sapphire film 19. The protruding portion of the calcite slide embedded in the sapphire film 19 was polished flat and smooth using a LaboPol-60 high-precision polishing machine at 500 rpm. The resulting calcite slide had a diameter and thickness of 27 mm by 3 mm, and the surface roughness of the calcite and sapphire surfaces was 326 nm.

[0085] Calcite slide cleaning: The calcite slide was placed in a mixture of toluene and methanol (toluene: methanol = 1:1) and ultrasonicated for 2 h. Then, the slide was rinsed repeatedly with deionized water 8 times to remove impurities on the surface of the calcite slide. Finally, the slide was dried at room temperature (25°C) in a DFS1000C dust-free oven.

[0086] Step S30, measuring the initial wettability of the glass slide and etching the glass slide;

[0087] The contact angle was calculated based on the Young-Joubert principle;

[0088]

[0089] Where: σ os is the interfacial tension between oil and solid, in millinewton per meter (mN / m); σ ws is the interfacial tension between water and solid, in millinewton per meter (mN / m); σ ow is the interfacial tension between oil and water, in millinewton per meter (mN / m); θ c is the contact angle, in degrees (°).

[0090] The wettability determination by contact angle method is shown in the following table:

[0091] contact angle <![CDATA[0°≤θ c <75°]]> <![CDATA[75°≤θ c ≤105°]]> <![CDATA[105°<θ c ≤180°]]> Wettability hydrophilic Neutral wetting lipophilic

[0092] If the droplet is water, use the upper table to determine the wettability; if the droplet is oil, use the lower table to determine the wettability.

[0093] contact angle <![CDATA[0°≤θ c <75°]]> <![CDATA[75°≤θ c ≤105°]]> <![CDATA[105°<θ c ≤180°]]> Wettability lipophilic Neutral wetting hydrophilic

[0094] Compare the contact angle measurement results of the glass slide with the contact angle of the actual oil reservoir rock. If the measurement results of the two differ within 3%, it can be considered that the wettability of the two is consistent and there is no need to treat the glass slide surface. If the measurement results of the two differ by more than 3%, it is necessary to soak the calcite glass slide in reservoir crude oil, set the temperature and pressure to match the reservoir, age it for 5 to 7 days, and measure the contact angle of the calcite glass slide until the error with the reservoir rock is less than 3% before etching the glass slide.

[0095] Initial wettability was determined by placing a calcite slide in the core chamber of a DSA100 contact angle meter. Using a needle equipped with a curved tip, oil was dripped onto the slide. An image of the oil droplet formation was captured while dripping. The Young-Juebni principle (Equation 1) was used to calculate the contact angle to 21.3°, indicating oil-wet wettability. The measured contact angle for the actual reservoir core was 21.8°, with an error of 2.3%, meeting the requirement of an error of less than 3%.

[0096] Slide etching: Apply thickening glue and UV photoresist, place the film on the glue machine suction cup, add a certain amount of glue in the center of the film, start the glue machine, and spread the thickening glue and UV photoresist evenly on the film surface at a speed of 2500r / min; Etching, the designed model Figure 2 Import the photolithography system, map it on the DMD display screen, and use ultraviolet light to engrave the pattern on the film; develop, put the film photolithography model into the developer diluted with deionized water, remove the photoresist and viscosity-enhancing glue in the photolithography pattern area, and show the complete Figure 2 Model structure; wax sealing, dissolve the wax at high temperature to form wax liquid, immerse the bottom of the developed film model in the wax liquid so that the bottom is first wrapped by the wax liquid, and then apply wax liquid around the film model and the areas without patterns on the surface; acid etching, immerse the sealed film model in a 10% hydrochloric acid solution, shake it gently for a while, and etch out the complete model structure Figure 2The acid etching time needs to be adjusted according to the size and complexity of the model's pore structure. Remove the wax coating from the film model surface, place it in a degumming solution, remove excess UV photoresist and adhesive, and rinse repeatedly with deionized water 2-3 times. Cut channels: Use a precision cutting machine, Secotom-60, to cut fluid inlet and outlet channels on the surface of the calcite glass slide, and cut an extraction channel on the sapphire film with a channel depth of 35 microns. Injection grooves I 10, II 11, and III 12, each 5 mm wide and 10 mm deep, are cut on the sapphire film 19 at positions corresponding to injection channels 3I, II4, and III5. Fluid capsules 42 are placed inside the grooves. Distributed optical fibers are embedded in pre-filled grooves 14, 20 mm long, 0.5 mm wide, and 40 μm deep, on the sapphire film 19. The OSI-D dynamic distributed optical fiber sensing system transmits and receives signals, measuring the oil and water content in the model pores and collecting data every 5 minutes.

[0097] Among them, since the pore channels of fracture-type carbonate reservoirs and fracture-type carbonate reservoirs are large and contain cracks and pores, 10% hydrochloric acid is used during acid etching to achieve acid etching of the model by controlling the acid etching time; however, porous carbonate reservoirs are relatively dense and have small pore channels. If low-concentration hydrochloric acid is used, uncontrollable situations may occur, such as the acid etching depth does not meet the standard, the glass surface has been acid-etched, or the acid etching speed is too fast, resulting in excessive pore channels. 4% hydrochloric acid + 8% citric acid is used for acid etching. The ratio of hydrochloric acid to citric acid can be adjusted according to the different calcite content of the glass slide to ensure that the depth and width of the pores meet the requirements during the glass slide etching process. The adjustment range of the hydrochloric acid ratio is 5% to 20%, and the adjustment range of the citric acid ratio is 80% to 95%.

[0098] Step S40: placing the glass slide in a carbonate reservoir multi-scale process simulation device;

[0099] Place the sapphire film on the clamping device 19; inject the experimental fluid oil into the fluid capsule 42 in advance, and place the fluid capsule 42 into the injection tank I 10, injection tank II 11, and injection tank III 12; place the sapphire cover plate on 20; place the clamping upper part 21 on the clamping lower part 24, rotate the clamping device upper part 21 clockwise, and tightly fit the sapphire film 19, sapphire cover plate 20, and PTFE gasket 23 through the thread 22; use the plug to plug the injection pipeline I 15 and injection pipeline II 16, slowly inject nitrogen from the injection pipeline III 17, place the production pipeline 18 in water, and check the sealing;

[0100] Place the clamping device 38 on the fixed bracket 40 inside the pressure chamber 37; install the sapphire observation window 25 and the sapphire light-transmitting window 39;

[0101] Step S50: Connect the outlet of the XHGD external circulation high and low temperature integrated thermostatic bath to the fluid inlet 35, and connect the inlet of the XHGD external circulation high and low temperature integrated thermostatic bath to the fluid outlet 36, so that the fluid circulates in the temperature control chamber 34. Set the temperature of the XHGD external circulation high and low temperature integrated thermostatic bath to the reservoir temperature of 87°C to heat the entire device. The temperature sensor 29 monitors the temperature in real time.

[0102] Step S60: Close the gas outlet 27 and connect nitrogen to the gas inlet 26, so that the nitrogen enters the pressure chamber 37 to pressurize the entire model. The pressure is monitored and controlled by the pressure sensor 28 and is set to the reservoir formation pressure of 10 MPa.

[0103] Step S70: Connect the vacuum pump to the injection valve III 32, close the injection valve I 30, the injection valve II 31 and the extraction valve 33, turn on the vacuum pump, and evacuate for 60 minutes.

[0104] Step S80: Connect the micro-injection pump to the injection valve I 30, close the injection valve II 31 and the injection valve III 32, open the production valve 33, set the injection rate to 0.001 mL / min, and inject the hydraulic oil into the elastic groove 41 on the fluid capsule 42 in the auxiliary injection tank I 10 to squeeze the fluid capsule 42 so that the oil quickly enters the pore throat. Observe the saturated oil in the model pore throat through the sapphire observation window 25 under a microscope. When the model pore throat is full of oil, close the micro-injection pump.

[0105] Step S90, connect the micro-injection pump to the injection valve I30, close the production valve 33 and the injection valve III32, open the injection valve II31, stand the entire device sideways, set the injection rate to 0.1 mL / min, inject hydraulic oil into the elastic groove 41 on the fluid capsule 42 in the injection tank II11, squeeze the fluid capsule 42 to allow formation water to enter the channel, clean the channel, and observe through the sapphire observation window 25 under a microscope to see if the oil in the fluid storage chamber I7 is flushed clean. When flushed clean, close the micro-injection pump.

[0106] Step S100: Place the entire device at an oil reservoir temperature of 87° C. for 48 hours.

[0107] Step S110: Connect the micro-injection pump to the injection valve III 32, close the injection valve I 30 and the injection valve II 31, open the production valve 33, and use a micrometer to measure the produced fluid at the production valve 33; set the injection rate to 0.005 mL / min, so that the hydraulic oil enters the elastic groove 41 on the fluid capsule 42 in the injection tank III 12, squeezes the fluid capsule 42, and causes formation water to enter the pore throats of the glass slide. Observe the water-to-oil displacement process through the sapphire observation window 25 under a microscope, and use an image acquisition system to capture images of the displacement process. When the oil in the pore throats of the model is not being used, the experiment ends, close the XHGD external circulation high and low temperature integrated constant temperature bath, release the fluid in the temperature control chamber 34 from the fluid outlet 36, open the gas outlet 27, unload the pressure in the pressure chamber 37, disassemble the model, and remove the calcite glass slide;

[0108] Step S120: Analysis of the type and content of the remaining oil after water flooding:

[0109] The distribution characteristics and types of residual oil in the rock pores after flooding were observed under a V20 Zeiss stereo microscope, and the types and contents of the residual oil were identified and calculated using Matlab software combined with Photoshop software. X-ray micro-CT was used to scan cylindrical thin sections of real reservoir cores after water flooding to identify the types of residual oil and calculate the content of each type of residual oil. The types and contents of the residual oil after water flooding on the glass slides were compared with those after water flooding in real reservoirs. If the error was less than 10%, the etched calcite glass slide was considered to fully simulate the reservoir. If it was greater than 10%, re-etching was required.

[0110] The types and contents of the residual oil obtained in this example are shown in the table below:

[0111]

[0112]

[0113] As can be seen from the table above, the residual oil content of each type is within the error range of 10%, so the etched calcite glass slide can completely simulate the carbonate reservoir.

[0114] Step S130, slide cleaning: Use anhydrous ethanol solution to clean the oil on the surface of the calcite slide, place it in a mixture of toluene and methanol (toluene: methanol 1:1) and ultrasonicate for 2 hours, rinse it repeatedly with deionized water 8 times to clean the surface of the calcite slide, and place the cleaned calcite slide in a DFS1000C dust-free oven to dry (temperature 25°C).

[0115] Step S140, wettability measurement: The calcite glass slide is immersed in crude oil and aged for 7 days. The calcite glass slide is placed in the core chamber of the DSA100 contact angle measuring instrument. Oil is dripped onto the calcite glass slide sample in the core chamber using a needle tube equipped with a curved tube head. While dripping the oil, an image of the oil droplet formation is captured. The contact angle is calculated according to the Young-Jueb principle (Equation 1) to be 22.1°. The wettability is determined to be oil-wet, meeting the error requirement of less than 3%.

[0116] Example 2

[0117] A certain oil field is a porous carbonate reservoir with an average porosity of 10.1%, small pore volume, reservoir temperature of 105℃ and reservoir pressure of 23MPa.

[0118] A multi-scale process simulation method for carbonate reservoirs specifically comprises the following steps:

[0119] Step S10: model design;

[0120] Skeleton extraction: Designed and extracted based on the real core casting thin section map of the oil field reservoir Figure 10 The real core pore structure is extracted using PS editing software. Figure 10 Fill Hole 2 in the image with white. After filling, select all white areas and invert the color. Fill Rock 1 with black. Modify the connection between Hole and Rock, remove the large jagged edges of Hole, and make the Hole structure curve smooth. Porosity is the pore volume of rock V. p and the rock surface volume V b The model is an etching model, and its etching depth remains unchanged. Therefore, the calculation process is converted into the calculation of the corresponding area ratio. Figure 10 The total pixel value 65790 can be calculated Figure 10 The structural porosity is 10.5%, which is close to the average porosity of the reservoir.

[0121] Hole structure in rock Figure 2 Injection channels and production channels are drawn at both ends, and a fluid cavity is drawn at a distance of 1mm from the rock pore structure between the injection channel and the production channel. The size of the fluid chamber is length × width = 7mm × 1mm. The materials used for the fluid capsule 42 placed in the injection grooves 10, 11, and 12 include but are not limited to fluororubber and polytetrafluoroethylene PTFE composites, and silicone rubber-based composite materials. They are acid and alkali resistant, temperature resistant at 200°C, and pressure resistant at 30MPa. They are acid and alkali resistant, temperature resistant at 200°C, and pressure resistant at 30MPa, and have high elasticity. The size of the fluid capsule is 5mm in diameter × 10mm in length. The connection between the fluid capsule 42 and the injection channels 3, 4, 5 and the one-way valve 44 is sealed with a sealing ring 45 and a sealing ring 9 to ensure good sealing of the connection. The sealing rings 9 and 45 used are made of perfluororubber, which are resistant to acid and alkali corrosion and resistant to high temperature and high pressure.

[0122] Step S20: making and cleaning glass slides;

[0123] Preparation of calcite slides: Select colorless, transparent, and glossy calcite and use a precision cutting machine Secotom-60 to cut it along its cleavage direction into cylindrical calcite slices with a diameter of 27 mm and a thickness of 6 mm. Cut the sapphire film 19 into a cylinder with a diameter of 35 mm and a thickness of 10 mm, with a middle groove size of 27 mm and 3 mm. Place the cut calcite slice into the groove in the middle of the sapphire film.

[0124] The protruding part of the calcite sheet embedded in the sapphire film was polished and smoothed at a speed of 500 rpm using a high-precision polishing grinder LaboPol-60. The diameter and thickness of the calcite glass slide after polishing were 27 mm × 3 mm, and the surface undulation height of the calcite and sapphire after polishing was 326 nm.

[0125] Calcite slide cleaning: The calcite slide was placed in a mixture of toluene and methanol (toluene: methanol = 1:1) and ultrasonicated for 2 h. Then, the slide was rinsed repeatedly with deionized water 8 times to remove impurities on the surface of the calcite slide. Finally, the slide was dried at room temperature (25°C) in a DFS1000C dust-free oven.

[0126] Step S30, measuring the initial wettability of the glass slide and etching the glass slide;

[0127] Initial wettability was determined by placing a calcite slide in the core chamber of a DSA100 contact angle meter. Using a needle equipped with a curved tip, oil was dripped onto the slide. An image of the oil droplet formation was captured while dripping. The Young-Juebni principle (Equation 1) was used to calculate the contact angle to be 20.5°, indicating oil-wet wettability. The measured contact angle for the actual reservoir core was 21.1°, with an error of 2.8%, meeting the requirement of an error of less than 3%.

[0128] Glass slide etching: Apply thickening glue and ultraviolet photoresist, place the film on the suction cup of the glue spreader, add a certain amount of glue to the center of the film, start the glue spreader, and evenly spread the thickening glue and ultraviolet photoresist on the surface of the film at a speed of 2500r / min; Etching, import the designed model diagram into the photolithography system, map it on the DMD display, and engrave the pattern on the film by ultraviolet light; Development, place the film photolithography model into the developer diluted with deionized water, remove the photoresist and thickening glue in the photolithography pattern area, and reveal the complete model structure; Wax sealing, dissolve the wax at high temperature to form wax liquid, immerse the bottom of the developed film model in the wax liquid, so that the bottom is first wrapped by the wax liquid, and then apply the wax liquid around the film model and the areas without patterns on the surface; Acid etching, immerse the sealed film model in a solution of 4% hydrochloric acid and 8% citric acid mixed in a ratio of 1:5, shake it gently for a while, control the acid etching time to 45s, and acid-etch out the complete model structure. Figure 10 The acid etching time needs to be adjusted according to the size and complexity of the model's pore structure. Remove the wax coating on the surface of the film model, place it in the degumming solution, remove the excess UV photoresist and tackifying glue on the surface, and rinse it repeatedly with deionized water 2-3 times;

[0129] Cutting channel: Use precision cutting machine Secotom-60 to cut the fluid inlet and outlet channels on the surface of calcite glass slide, and cut the extraction channel on the sapphire substrate. The channel depth is 35 microns. Cut the injection groove with a width of 5mm and a depth of 10mm at the corresponding position of the sapphire substrate 19 and the glass injection channel. Place polyester film inside the groove. Distributed optical fibers were embedded in the pre-filled grooves 14 on the sapphire substrate 19, and the OSI-D dynamic distributed optical fiber sensing system was used to transmit and receive signals, measuring the oil and water content in the model pores and collecting data every 5 minutes.

[0130] Step S40: placing the glass slide in a carbonate reservoir multi-scale process simulation device;

[0131] Place the sapphire film on the clamping device 19; inject the experimental fluid oil into the fluid capsule 42 in advance, and place the fluid capsule 42 into the injection tank I 10, injection tank II 11, and injection tank III 12; place the sapphire cover plate on 20; place the clamping upper part 21 on the clamping lower part 24, rotate the clamping device upper part 21 clockwise, and tightly fit the sapphire film 19, sapphire cover plate 20, and PTFE gasket 23 through the thread 22; use the plug to plug the injection pipeline I 15 and injection pipeline II 16, slowly inject nitrogen from the injection pipeline III 17, place the production pipeline 18 in water, and check the sealing;

[0132] Place the clamping device 38 on the fixed bracket 40 inside the pressure chamber 37; install the sapphire observation window 25 and the sapphire light-transmitting window 39;

[0133] Step S50: Connect the outlet of the XHGD external circulation high and low temperature integrated thermostatic bath to the fluid inlet 35, and connect the inlet of the XHGD external circulation high and low temperature integrated thermostatic bath to the fluid outlet 36, so that the fluid circulates in the temperature control chamber 34. Set the temperature of the XHGD external circulation high and low temperature integrated thermostatic bath to the reservoir temperature of 87°C to heat the entire device. The temperature sensor 29 monitors the temperature in real time.

[0134] Step S60: Close the gas outlet 27 and connect nitrogen to the gas inlet 26, so that the nitrogen enters the pressure chamber 37 to pressurize the entire model. The pressure is monitored and controlled by the pressure sensor 28 and is set to the reservoir formation pressure of 10 MPa.

[0135] Step S70: Connect the vacuum pump to the injection valve III 32, close the injection valve I 30, the injection valve II 31 and the extraction valve 33, turn on the vacuum pump, and evacuate for 60 minutes.

[0136] Step S80, connect the micro-injection pump to the injection valve I 30, close the injection valve II 31 and the injection valve III 32, open the production valve 33, set the injection rate to 0.001 mL / min, inject hydraulic oil into the elastic groove 41 on the fluid capsule 42 in the auxiliary injection channel fluid capsule groove 10, squeeze the fluid capsule 42, so that the oil quickly enters the pore throat, observe the saturated oil in the model pore throat through the sapphire observation window 25 under a microscope, and when the model pore throat is full of oil, close the micro-injection pump.

[0137] Step S90, connect the micro-injection pump to the injection valve I30, close the production valve 33 and the injection valve III32, open the injection valve II31, stand the entire device sideways, set the injection rate to 0.1 mL / min, inject hydraulic oil into the elastic groove 41 on the fluid capsule 42 in the injection tank II11, squeeze the fluid capsule 42 to allow formation water to enter the channel, clean the channel, and observe through the sapphire observation window 25 under a microscope to see if the oil in the fluid storage chamber I7 is flushed clean. When flushed clean, close the micro-injection pump.

[0138] Step S100: Place the entire device at an oil reservoir temperature of 105° C. for 24 hours.

[0139] Step S110: Connect the micro-injection pump to the injection valve III 32, close the injection valve I 30 and the injection valve II 31, open the production valve 33, and use a micrometer to measure the output fluid at the production valve 33; set the injection rate to 0.005 mL / min, so that the hydraulic oil enters the elastic groove 41 on the fluid capsule 42 in the injection tank III 12, squeezes the fluid capsule 42, and allows the formation water to enter the pore throats of the glass slide. Observe the water-to-oil process through the sapphire observation window 25 under a microscope and use the image acquisition system to capture images of the displacement process. When the oil in the pore throats of the model is not being used, the experiment ends, close the XHGD external circulation high and low temperature integrated constant temperature bath, release the fluid in the temperature control chamber 34 from the fluid outlet 36, open the gas outlet 27, unload the pressure in the pressure chamber 37, disassemble the model, and remove the calcite glass slide.

[0140] Step S120, analysis of the type and content of the remaining oil after the water flooding is completed: the distribution characteristics and type of the remaining oil in the rock pores after the flooding is observed under a V20 Zeiss stereo microscope. The type and content of the remaining oil are identified and calculated using Matlab software combined with Photoshop software. The remaining oil type and content are shown in the following table:

[0141]

[0142]

[0143] As can be seen from the table above, the residual oil content of each type is within the error range of 10%, so the etched calcite glass slide can completely simulate the carbonate reservoir.

[0144] Step S130, slide cleaning: Use anhydrous ethanol solution to clean the oil on the surface of the calcite slide, place it in a mixture of toluene and methanol (toluene: methanol 1:1) and ultrasonicate for 2 hours, rinse it repeatedly with deionized water 8 times to clean the surface of the calcite slide, and place the cleaned calcite slide in a DFS1000C dust-free oven to dry (temperature 25°C).

[0145] Step S140, wettability measurement: The calcite glass slide is immersed in crude oil and aged for 7 days. The calcite glass slide is placed in the core chamber of the DSA100 contact angle measuring instrument. Oil is dripped onto the calcite glass slide sample in the core chamber using a needle equipped with a curved tube head. While dripping the oil, an image of the oil droplet formation is captured. The contact angle is calculated according to the Young-Jueb principle (Equation 1) to be 20.7°. The wettability is determined to be oil-wet, meeting the error requirement of less than 3%.

[0146] The above description does not limit the present invention in any form. Although the present invention has been disclosed through the above embodiments, it is not intended to limit the present invention. Any technician familiar with the profession can use the technical content disclosed above to make some changes or modifications to equivalent embodiments without departing from the scope of the technical solution of the present invention. However, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are within the scope of the technical solution of the present invention.

Claims

1. A multi-scale process simulation device for carbonate reservoirs, characterized in that: It comprises a jacketed simulation cylinder, a glass slide (7), a sapphire film (19), a sapphire cover film (20), a pressure chamber (37), and a clamping device (38); The sapphire bottom plate (19) is provided with a mounting groove and an injection groove I (10), an injection groove II (11), an injection groove III (12), and an extraction groove (13) communicating with the mounting groove; the glass slide (7) is installed in the mounting groove; the injection groove I (10), the injection groove II (11), and the injection groove III (12) are respectively provided with fluid capsules (42); The clamping device (38) is provided with an injection line (15), an injection line (16), an injection channel (17), and a withdrawal line (18) which are sequentially connected to the injection tank I (10), the injection tank II (11), the injection tank III (12), and the withdrawal tank (13). The dimensions of the injection tank are length × width × height = 10 mm × 5 mm × 3 mm. The jacketed simulation cylinder comprises a temperature control chamber (34) and a pressure chamber (37); the sapphire cover plate (20) covers the sapphire bottom plate (19) and is installed together in a clamping device (38); the clamping device (38) is installed in the pressure chamber (37).

2. The multi-scale process simulation device for carbonate reservoirs according to claim 1, characterized in that: The glass slide (7) is provided with a rock slice (1), an injection channel I (3), an injection channel II (4), an injection channel III (5), an extraction channel (6), and a fluid chamber (8); the fluid chamber (8) is located at the left and right ends of the rock slice (1); the injection channel I (3), the injection channel II (4), and the injection channel III (5) are all in communication with the fluid chamber (8) on the left side of the rock slice (1), and the extraction channel (6) is in communication with the fluid chamber (8) on the right side of the rock slice (1).

3. The multi-scale process simulation device for carbonate reservoirs according to claim 1, characterized in that: The clamping device (38) comprises a clamping upper part (21) and a clamping lower part (24) which are threadedly connected.

4. A multi-scale process simulation device for carbonate reservoirs according to claim 3, characterized in that: The sapphire bottom plate (19) and the sapphire cover plate (20) are both provided with a tetrafluoroethylene gasket (23).

5. The multi-scale process simulation device for carbonate reservoirs according to claim 1, characterized in that: The upper and lower ends of the jacketed simulation cylinder are respectively provided with a sapphire observation window (25) and a sapphire light-transmitting window (39).

6. The multi-scale process simulation device for carbonate reservoirs according to claim 1, characterized in that: The jacketed simulation cylinder is provided with a fluid inlet (35) and a fluid outlet (36) communicating with the temperature control chamber (34), and a gas inlet (26) and a gas outlet (27) communicating with the pressure chamber (37).

7. The multi-scale process simulation device for carbonate reservoirs according to claim 1, characterized in that: A pressure sensor (28) and a temperature sensor (29) are provided in the jacketed simulation cylinder.

8. The multi-scale process simulation device for carbonate reservoirs according to claim 1, characterized in that: The injection pipeline (15), the injection pipeline (16), the injection channel (17), and the production pipeline (18) are respectively provided with an injection valve I (30), an injection valve II (31), an injection valve III (32), and a production valve (33).

9. A multi-scale process simulation method for carbonate reservoirs, characterized in that: The method uses a carbonate reservoir multi-scale process simulation device according to any one of claims 1 to 8 to perform simulation, and specifically comprises the following steps: Step S10: model design; The binary graph of the rock pore throat structure is extracted based on the thin slices of cast body sampled from the real carbonate core in the oil field. The injection channel I (3), injection channel II (4), injection channel III (5), and production channel (6) are drawn at both ends of the rock pore throat structure. The fluid cavity (8) is drawn 1 mm away from the injection channel III (5) and the production channel (6) to the rock pore throat structure. The size of the fluid cavity (8) is length × width = 7 mm × 1 mm. The fluid capsule 42 placed in the injection grooves 10, 11, and 12 is made of materials including but not limited to a composite of fluororubber and polytetrafluoroethylene (PTFE), or a silicone rubber-based composite material. The fluid capsule is acid-resistant, alkali-resistant, heat-resistant at 200°C, and pressure-resistant at 30 MPa. The fluid capsule has high elasticity and a size of 5 mm in diameter and 10 mm in length. The connection between the fluid capsule 42 and the injection channels 3, 4, and 5 is sealed by a sealing ring 9. The connection between the fluid capsule 42 and the one-way valve 44 is sealed by a sealing ring 45 to ensure good sealing of the connection. The sealing rings 9 and 45 are made of perfluororubber, which has the characteristics of acid and alkali corrosion resistance and high temperature and high pressure resistance. Step S20: making and cleaning glass slides; Select colorless, transparent, and glossy calcite, and cut it into cylindrical calcite sheets along its cleavage direction using a precision cutting machine; Embed the cut cylindrical calcite piece into a sapphire plate with a groove in the middle. Use a high-precision polishing machine at 500 rpm to polish the protruding part of the calcite piece embedded in the sapphire plate until it is flat and smooth. The dimensions of the polished calcite glass slide are 27 mm in diameter × 3 mm in thickness. The surface roughness of the calcite and sapphire after polishing is ≤ 500 nm. Place the calcite glass slide in a mixture of toluene and methanol (toluene: methanol = 1:1) and sonicate for 2 h, then rinse repeatedly with deionized water for at least 5 times, and finally dry at room temperature in a dust-free box; Step S30, measuring the initial wettability of the glass slide and etching; According to the wettability of real carbonate oil reservoirs, glass slides with different calcite contents were selected to measure whether the initial wettability of the calcite glass slides was consistent with the wettability of the reservoir rock; Then, pattern etching is performed. During the etching process, carbonate reservoirs are classified and etched with different acid solutions. During the acid etching, carbonate reservoirs are classified and etched. Fracture-type and fracture-type carbonate reservoirs have larger pore channels and contain fractures and pores, and are etched with 10% hydrochloric acid. Porous carbonate reservoirs have smaller pore channels and are etched with 4% hydrochloric acid + 8% citric acid. The ratio of hydrochloric acid to citric acid is adjusted according to the calcite content of the glass slide. The adjustment range of the hydrochloric acid ratio is 5% to 20%, and the adjustment range of the citric acid ratio is 80% to 95%. Cut out the extraction channel on the sapphire film, cut out grooves at the positions corresponding to the sapphire film and the glass slide injection and auxiliary injection channels; cut out a pre-filling groove at the lower part of the sapphire film; Step S40, placing the glass slide (7) in a carbonate reservoir multi-scale process simulation device; Step S50: Connect the outlet of the XHGD external circulation high and low temperature integrated thermostatic bath to the fluid inlet (35), and connect the inlet of the XHGD external circulation high and low temperature integrated thermostatic bath to the fluid outlet (36), so that the fluid circulates in the temperature control chamber (34), and set the temperature of the XHGD external circulation high and low temperature integrated thermostatic bath to the reservoir temperature of 105°C to heat the entire device, and the temperature sensor (29) monitors the temperature in real time; Step S60: close the gas outlet (27), connect nitrogen to the gas inlet (26), so that the nitrogen enters the pressure chamber (37) to pressurize the entire glass slide (7), and monitor and control the pressure through the pressure sensor (28), setting the pressure to the reservoir formation pressure of 23 MPa; Step S70: Connect the vacuum pump to the injection valve III (32), close the injection valve I (30), injection valve II (31), and extraction valve (33), turn on the vacuum pump, and evacuate for 60 minutes; Step S80: performing an oil displacement experiment test; Step S90, comparing the type and content of the remaining oil on the glass slide (7) after the water flooding is completed with that of the actual reservoir after the water flooding is completed. If the error is less than 10%, it is considered that the etched calcite glass slide can completely simulate the reservoir. If it is greater than 10%, it is necessary to re-etch according to step S30; Step S100: Clean the glass slide (7) after testing and measure the wettability.

10. The multi-scale process simulation method for carbonate reservoirs according to claim 9, characterized in that: The specific process of step S80 includes: Step S81, connect the micro-injection pump to the injection valve I (30), close the injection valve II (31) and the injection valve III (32), open the extraction valve (33), inject hydraulic oil into the injection tank I (10) to squeeze the fluid capsule (42), so that the oil quickly enters the pore throat, observe the saturated oil in the model pore throat through the sapphire observation window (25) under a microscope, and when the model pore throat is full of oil, close the micro-injection pump; Step S82: Connect the micro-injection pump to the injection valve I (30), close the extraction valve (33) and the injection valve III (32), and open the injection valve II (31); stand the entire device sideways, inject hydraulic oil into the injection tank II (11), squeeze the fluid capsule (42) to allow formation water to enter the channel, clean the channel, observe through the sapphire observation window (25) under a microscope to see if the oil in the fluid chamber (8) has been flushed clean, and close the micro-injection pump when it is flushed clean; Step S83: Place the entire device at an oil reservoir temperature of 105° C. for 24 hours; Step S84, connect the micro-injection pump to the injection valve III (32), close the injection valve I (30) and the injection valve II (31), open the production valve (33), and use a micro-meter to measure the output fluid at the production valve (33); allow the hydraulic oil to enter the injection tank II12 to squeeze the fluid capsule (42) so that the formation water enters the pore throat of the glass slide, observe the water displacement process through the sapphire observation window (25) under a microscope, and use the image acquisition system to collect the displacement process image. When the oil in the pore throat of the model is not activated, the experiment ends, close the XHGD external circulation high and low temperature integrated constant temperature bath, release the fluid in the temperature control chamber (34) from the fluid outlet (36), open the gas outlet (27), unload the pressure in the pressure chamber (37), disassemble the model and take out the glass slide (7).

Images