CN117607336A - A porous media flow reaction visualization system - Google Patents

Abstract

The invention discloses a porous medium flow reaction visualization system which comprises a rotating frame, a reaction device, a porous medium etching sheet, a heating mechanism, a pressurizing mechanism, a collecting mechanism, a camera system and a computer, wherein the porous medium etching sheet is arranged in the reaction device, the heating mechanism is arranged on the reaction device, an injection port of the reaction device is communicated with the pressurizing mechanism, an output port of the reaction device is communicated with the collecting mechanism, the reaction device is connected to the rotating frame, a rotating shaft of the rotating frame is horizontally arranged, a transparent window capable of observing the porous medium etching sheet is arranged on the reaction device, the camera system is positioned above the transparent window, and the rotating frame, the heating mechanism, the pressurizing mechanism and the camera system are all in communication connection with the computer. The method can reproduce the flowing reaction process of the porous medium of the reservoir, observe and identify the precipitation position, nucleation growth and crystallization form of mineral particles, and summarize and analyze the precipitation rules of minerals in different heat collection modes and the influence conditions on a seepage channel.

Description

A porous media flow reaction visualization system

Technical field

The invention relates to the technical field of geothermal research, and in particular to a porous medium flow reaction visualization system.

Background technique

As the energy crisis and environmental problems become increasingly severe, it is imperative to optimize and transform the energy structure. As a renewable energy source with good prospects, geothermal energy has the advantages of low pollution, stable operation and low maintenance costs, making it an alternative to conventional fossil energy and helping to realize a low-carbon economic society. my country's deep sandstone reservoirs are widely distributed, have high temperatures and are rich in geothermal resources, which are worthy of greater efforts to develop.

However, affected by the depth of the reservoir and diagenesis, its natural permeability is low, and the problem of water injection and heat recovery is prominent. Not only is it difficult to reinject the formation water, but the chemical precipitation caused by the incompatibility of the reinjection water can also easily block the reservoir seepage channels. . For this reason, some scholars have proposed using the excellent flow capacity of supercritical CO ₂ to cyclically inject and produce CO ₂ to develop geothermal heat in deep sandstone reservoirs. However, the continuous injection of CO ₂ will cause the formation water to evaporate, causing the mineral ion concentration in the formation water to continue to increase until it is saturated and precipitated, blocking the reservoir pores. It can be seen that no matter whether the formation water recirculation method or the cyclic _CO2 injection and production method is used to exploit deep sandstone geothermal reservoirs, complex reactions will occur during the reservoir flow process and will affect the physical properties of the reservoir and the heat recovery efficiency.

With the gradual exploitation of deep earth resources, the requirements for visual experiments are getting higher and higher. After investigation, there are currently no geothermal reservoir-related reaction devices on the market. Similar products in the oil and gas field also have different types of visualization due to different research goals and production methods. There are no fixed standards.

In order to reveal the flow reaction mechanism of deep sandstone reservoirs under the two methods of conventional water injection cyclic heat recovery and cyclic CO ₂ heat recovery, and to intuitively evaluate the impact of the two methods on the physical properties of the reservoir, it is urgent to develop a porous medium flow reaction visualization The system can reproduce the flow reaction process of reservoir porous media, observe and identify the precipitation location, nucleation growth and crystallization morphology of mineral particles, and summarize and analyze the precipitation patterns of minerals in different heat recovery methods and their impact on seepage channels.

Contents of the invention

The purpose of the present invention is to provide a porous medium flow reaction visualization system to solve the above-mentioned problems existing in the prior art and enable the observation of the flow reaction process of the porous medium in the reservoir.

In order to achieve the above objects, the present invention provides the following solutions:

The invention provides a porous media flow reaction visualization system, which includes a rotating frame, a reaction device, a porous media etching sheet, a heating mechanism, a pressurizing mechanism, a collection mechanism, a camera system and a computer. The porous media etching sheet is arranged on In the reaction device, the heating mechanism is provided on the reaction device, the injection port of the reaction device is connected to the pressurizing mechanism, the output port is connected to the collection mechanism, and the reaction device is connected to the On the rotating frame, the rotating axis of the rotating frame is set horizontally, the reaction device is provided with a transparent window through which the porous media etching sheet can be observed, the camera system is located above the transparent window, and the rotating The frame, the heating mechanism, the pressurizing mechanism and the camera system are all communicatively connected with the computer.

Preferably, the rotating frame is a hydraulic rotating clamp, and both sides of the reaction device are respectively fixedly connected to the rotating shaft of the rotating clamp.

Preferably, the reaction device includes an upper cover, a middle layer and a lower cover. The upper cover and the lower cover are sealingly connected to the middle layer through bolts respectively, and form a sealed reaction chamber. The porous medium etching sheet Detachably connected to the step of the middle layer, the transparent window is provided in the middle of the upper cover and the lower cover, and the injection port and the output port are respectively provided on the middle layer.

Preferably, the injection port and the output port are located on the diagonal line of the porous media etching sheet with a spacing of at least 90 mm, and a water film that can communicate with a water source is provided on the edge of the reaction chamber.

Preferably, the porous medium etching sheet is made of temperature-resistant and pressure-resistant glass, and is produced through CT scanning, microelectronic photolithography and pore throat sintering processes.

Preferably, the heating mechanism includes a heating jacket, an insulation jacket and a temperature controller. The heating jacket is set on the reaction device. The insulation jacket is set on the heating jacket. The heating jacket is connected to the temperature controller. The temperature controller is electrically connected, and the temperature controller is communicatively connected to the computer.

Preferably, the pressurizing mechanism includes an injection pump, a liquid tank and a gas tank, the injection pump is connected to the liquid tank and the gas tank respectively through a tee, and the liquid tank and the gas tank are both connected to the The injection port is connected.

Preferably, the gas tank is connected to a parallel high-pressure dryer and a high-pressure humidifier through a tee, and there is a pipe on the pipelines at both ends of the gas tank, and on the pipelines at both ends of the high-pressure dryer and the high-pressure humidifier. Valve; distilled water or formation water is provided in the liquid tank, and CO ₂ is provided in the gas tank.

Preferably, the collection mechanism includes a water collector and a dryer arranged in sequence, the end of the water collector outlet pipe is located at the top of the water collector, and a flow meter is connected behind the dryer. The computer is connected for communication.

Preferably, the camera system includes a digital microscope, a light source and a camera. The digital microscope is arranged above the transparent window and the light source is arranged below. The camera is used to capture images observed by the digital microscope. The camera is communicatively connected to the computer.

Compared with the prior art, the present invention achieves the following technical effects:

The invention can reproduce the flow reaction process of the reservoir porous medium, observe and identify the precipitation location, nucleation growth and crystallization morphology of mineral particles, summarize and analyze the precipitation rules of minerals in different heat extraction methods and the impact on seepage channels, and can be used for research Simulating flow response in deep sandstone geothermal reservoirs.

Description of drawings

In order to explain the embodiments of the present invention or the technical solutions in the prior art more clearly, the drawings needed to be used in the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some of the drawings of the present invention. Embodiments, for those of ordinary skill in the art, other drawings can also be obtained based on these drawings without exerting creative efforts.

Figure 1 is a schematic structural diagram of the porous media flow reaction visualization system of the present invention;

Figure 2 is a schematic diagram of the internal structure of the reaction device in the present invention;

Figure 3 is a schematic top view of the reaction device in the present invention;

Among them: 1-lower cover, 2-middle layer, 3-heating jacket, 4-rotating holder, 5-upper cover, 6-transparent window, 7-gasket, 8-sealing ring, 9-pressure plate, 10-back Pressure valve, 11-bolt, 12-positioning plate, 13-porous medium etching piece, 14-injection port, 15-output port, 16-injection pump, 17-high-pressure dryer, 18-high-pressure humidifier, 19-return Pressure valve, 20-temperature and pressure sensor, 21-water collector, 22-dryer, 23-electronic scale, 24-flow meter, 25-digital microscope, 26-camera, 27-computer, 28-intermediate container, 29- water film.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without any creative effort fall within the scope of protection of the present invention.

The purpose of the present invention is to provide a porous medium flow reaction visualization system to solve the problems existing in the existing technology and enable the observation of the flow reaction process of the porous medium in the reservoir.

In order to make the above objects, features and advantages of the present invention more obvious and understandable, the present invention will be described in further detail below with reference to the accompanying drawings and specific embodiments.

As shown in Figures 1 to 3: This embodiment provides a porous media flow reaction visualization system, including a rotating frame, a reaction device, a porous media etching sheet 13, a heating mechanism, a pressurizing mechanism, a collection mechanism, a camera system and The computer 27 and the porous medium etching sheet 13 are arranged in the reaction device. The reaction device is equipped with a heating mechanism. The inlet 14 of the reaction device is connected to the pressurizing mechanism and the output port 15 is connected to the collection mechanism. The reaction device is connected to the rotating frame. , the rotation axis of the rotating frame is set horizontally, and the reaction device is provided with a transparent window 6 through which the porous medium etching sheet 13 can be observed. The camera system is located above the transparent window 6. The rotating frame, heating mechanism, pressurizing mechanism and camera system are all Communication connection with computer 27.

Preferably, in this embodiment, the rotating frame is a hydraulic rotating clamp 4, and both sides of the reaction device are fixedly connected to the rotating shafts of the rotating clamp 4. The rotating holder 4 adopts a hydraulic rotating design, which allows the device to be placed at any angle in the vertical plane to study the effect of reservoir inclination on flow and reaction.

Preferably, in this embodiment, the reaction device includes an upper cover 5, a middle layer 2 and a lower cover 1. The upper cover 5 and the lower cover 1 are sealingly connected to the middle layer 2 through bolts 11 respectively, and form a sealed reaction chamber. A sealing ring 8 is provided between the cover 5, the middle layer 2 and the lower cover 1. A gasket 7 and a sealing ring 8 are provided between the transparent window 6 and the upper cover 5 and lower cover 1. The bolt 11 presses the transparent window 6 through the pressure plate 9. , to ensure the temperature and pressure resistance of the device. The porous medium etching sheet 13 is detachably connected to the step of the middle layer 2. The upper cover 5 and the lower cover 1 are respectively provided with transparent windows 6 in the middle. The injection port 14 and the output port 15 are respectively provided on the middle layer 2. The injection port 14 and the output port 15 are located on the diagonal line of the porous media etching sheet 13 with a spacing of at least 90 mm. A water film 29 is provided on the edge of the reaction chamber that can communicate with the water source. In this embodiment, there are injection holes at the diagonal corners of the porous medium etching sheet 13, and the distance between the opposite sides of the injection holes is 92 mm.

Preferably, the porous medium etching sheet 13 in this embodiment is made of temperature-resistant and pressure-resistant glass, and is made through CT scanning, microelectronic photolithography and pore throat sintering processes. Investigate existing geothermal resource development areas in China, analyze existing geothermal resource reservoir types, and collect corresponding deep thermal reservoir core samples based on reservoir types. The porous media etched sheet 13 in this embodiment is different from the commonly used ones. The micro-etching model uses micro-etching sheets made of special glass. With the help of the core CT scanning system, typical core samples in geothermal reservoirs are CT scanned to screen pore types and pore-fracture types with obvious pore structure characteristics. Image design mask; using electron lithography technology to produce microscopic porous media etching sheets 13, which not only can truly restore the pore throat structure in the reservoir, but also has temperature and pressure resistance, and can also be made into natural rock cores through thin-section model making equipment thin section; at the same time, a water film 29 connected to the water source was added to the edge of the model to study the impact of formation water backflow and water film connectivity on the precipitation of mineral particles when boundary water exists. The porous media etching sheet 13 is installed on the positioning plate 12 through screws. There are several screws evenly distributed around the positioning plate 12. The water film 29 and the porous media etching sheet 13 are connected to the positioning plate 12 through bolts in turn to facilitate etching. The chip can be replaced and the position of the etched chip can be corrected.

Preferably, in this embodiment, the heating mechanism includes a heating jacket 3, an insulation jacket and a temperature controller. The heating jacket 3 is set on the reaction device, the insulation jacket is set on the heating jacket 3, and the heating jacket 3 is electrically connected to the temperature controller. , the temperature controller is connected to the computer 27 for communication. In this embodiment, a semi-open heating jacket 3 and a heat preservation jacket are used. After the experiment is completed, the heat preservation jacket can be removed by simply opening the buckle on the heat preservation jacket. The heating jacket 3 can be disassembled conveniently and quickly. The heating can be controlled by Temperature, simulates geothermal reservoir temperature.

Preferably, in this embodiment, the pressurizing mechanism includes an injection pump 16 and an intermediate container 28. The intermediate container 28 includes a liquid tank and a gas tank. The injection pump 16 is connected to the liquid tank and the gas tank through a tee, and the liquid tank and the gas tank are respectively connected. The tanks are all connected to the injection port 14 for simulating geothermal reservoir pressure. The gas tank is connected to a parallel high-pressure dryer 17 and a high-pressure humidifier 18 through a tee. A valve is respectively provided on the pipelines at both ends of the gas tank, the high-pressure dryer 17 and the high-pressure humidifier 18; in the liquid tank Distilled water or formation water is provided, and CO ₂ is provided in the gas tank; temperature and pressure sensors 20 are respectively provided on the pipelines of the injection port 14 and the output port 15 to facilitate temperature and pressure detection of the medium therein, and the back pressure valve 19 is provided on On the pipeline of the injection port 14, a back pressure valve is connected to the reaction chamber to facilitate adjustment of the pressure in the reaction chamber.

Preferably, in this embodiment, the collection mechanism includes a water collector 21 and a dryer 22 arranged in sequence, in which the feed pipe is located at the bottom of the water collector 21 and the end of the discharge pipe is located at the top of the water collector 21 to facilitate The discharged water volume is collected and measured. A flow meter 24 is connected behind the dryer 22. An electronic scale 23 is provided at the bottom of the water collector 21 and the dryer 22 for detecting weight changes in each container. The flow meter 24 is connected to the computer. 27 communication connections to facilitate measurement of discharged gas flow.

Preferably, in this embodiment, the camera system includes a digital microscope 25, a light source and a camera 26. A digital microscope 25 is provided above the transparent window 6 and a light source is provided below. The camera 26 is used to capture images observed by the digital microscope 25. The camera 26 26 is connected to the computer 27 for communication. Through light source illumination, the microscopic flow characteristics of formation water and the mineral crystallization/precipitation process during fluid injection can be clearly observed and recorded.

The operation process of the porous media flow reaction visualization system of this embodiment specifically includes the following steps:

Before the experiment, open the reaction device and place the prepared porous medium etching sheet 13 on the etching sheet loading platform. Before placing it, clean the etching sheet with alcohol and fix it to the reaction device through the compression screw 11 and the positioning plate 12. inside; when placing, it is necessary to strictly match the injection holes at both ends and place them accurately at the corresponding positions, and then assemble and seal the reaction device cavity. Put the assembled reaction device into deionized water for cleaning to remove impurities that may enter when assembling the sealed cavity, and then place it in an oven to dry; connect other components of the porous media flow reaction visualization system as required.

Start the heating jacket 3 to heat to the set experimental temperature, close the back pressure valve 10 on the reaction chamber at the rear of the injection port 14, fill the CO ₂ injection chamber in Figure 1 with high-purity nitrogen, and inject it at a low injection rate. Slowly inject high-purity nitrogen into the reaction chamber to the experimental pressure condition, up to 20MPa, to test the sealing of the device. Open the back pressure valve 10 and inject the formation fluid (distilled water) into the visualization model from the injection port 14 at a flow rate of 0.01ml/min. The injection port 14 and the output port 15 are connected to the injection holes at the diagonal corners of the porous media etching sheet 13. When the fluid When the fluid is injected from the injection port 14 and flows (spreads) through the opposite corners of the porous media etching sheet 13, and when there is fluid output in the pipeline of the output port 15, the back pressure valve 10 is opened to adjust the pressure in the reaction chamber to the experimental set pressure. The fluid is injected into the model at a flow rate of 0.01ml/min-0.05ml/min until the research pressure is reached, and the microscopic flow process of the injected fluid is observed and recorded through the digital microscope 25 on the transparent window 6 .

During the experiment, different angles can be adjusted by rotating the holder 4 to study the effect of the reservoir inclination on the flow and reaction. After the experiment, close the back pressure valve 10 and the heating device, inject high-purity nitrogen at a flow rate of 0.01ml/min-0.05ml/min, and displace the previously injected fluid out of the device. Reproduced the flow reaction process of the reservoir porous media, observed and identified the precipitation location, nucleation growth and crystallization morphology of mineral particles, summarized and analyzed the precipitation patterns of minerals in different heat recovery methods and their impact on seepage channels; completed the geothermal water The compatibility visualization experiment during the recharge process and the formation water mineral precipitation experiment during the CO2 heat recovery process can also analyze the impact of pore structure on the reservoir flow response; combine the deep thermal reservoir porous media flow response visualization device with the existing high-temperature The high-pressure displacement equipment is connected, and the camera system is used to record the experimental flow and reaction process to study the reaction phenomena that occur during the fluid flow in the geothermal reservoir.

The porous media flow reaction visualization system of this embodiment can visually observe the flow process during heat recovery in deep sandstone reservoirs, and evaluate the impact of flow reactions (chemical precipitation of incompatible recharge water, evaporation and salt precipitation of formation water caused by CO ₂ ) on the reservoir. The influence of layer pores; it can realize microscopic simulation of geothermal water recharge and _CO2 heating environment, capture the microscopic flow characteristics of formation water and mineral crystallization/precipitation process during fluid injection, and quantify formation water flow and its impact on mineral precipitation. ; It can be used to simulate the flow response of deep sandstone geothermal reservoirs, filling a gap in this field internationally.

This specification uses specific examples to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea; at the same time, for those of ordinary skill in the art, based on this The idea of the invention will be subject to change in the specific implementation and scope of application. In summary, the contents of this description should not be construed as limitations of the present invention.

Claims (10)

1. A porous media flow reaction visualization system, characterized by: including a rotating frame, a reaction device, a porous media etching sheet, a heating mechanism, a pressurizing mechanism, a collection mechanism, a camera system and a computer, and the porous media etching sheet It is arranged in the reaction device, the heating mechanism is provided on the reaction device, the injection port of the reaction device is connected to the pressurizing mechanism, the output port is connected to the collection mechanism, and the reaction device is connected to On the rotating frame, the rotating axis of the rotating frame is set horizontally, the reaction device is provided with a transparent window through which the porous medium etching sheet can be observed, and the camera system is located above the transparent window, so The rotating frame, the heating mechanism, the pressurizing mechanism and the camera system are all communicatively connected with the computer. 2. The porous media flow reaction visualization system according to claim 1, characterized in that: the rotating frame is a hydraulic rotating clamp, and both sides of the reaction device are respectively fixed to the rotating shaft of the rotating clamp. connect. 3. The porous media flow reaction visualization system according to claim 1, characterized in that: the reaction device includes an upper cover, a middle layer and a lower cover, and the upper cover and the lower cover are respectively sealed with the middle layer through bolts. connected to form a sealed reaction chamber, the porous medium etching sheet is detachably connected to the step of the middle layer, the transparent window is correspondingly provided in the middle of the upper cover and the lower cover, and the injection The inlet and the output port are respectively provided on the middle layer. 4. The porous media flow reaction visualization system according to claim 1, characterized in that: the injection port and the output port are located on the diagonal line of the porous media etching sheet with a spacing of at least 90 mm, so The edge of the reaction chamber is provided with a water film that can communicate with the water source. 5. The porous medium flow reaction visualization system according to claim 1, characterized in that: the porous medium etching sheet is made of temperature-resistant and pressure-resistant glass, and is processed through CT scanning, microelectronic photolithography and pore throat sintering processes. be made of. 6. The porous medium flow reaction visualization system according to claim 1, characterized in that: the heating mechanism includes a heating jacket, a heat preservation jacket and a temperature controller, the heating jacket is set on the reaction device, and the heat insulation The sleeve is set on the heating jacket, the heating jacket is electrically connected to the temperature controller, and the temperature controller is communicatively connected to the computer. 7. The porous media flow reaction visualization system according to claim 1, characterized in that: the pressurizing mechanism includes an injection pump, a liquid tank and a gas tank, and the injection pump is connected to the liquid tank and the gas tank through a tee. The gas tank is connected, and both the liquid tank and the gas tank are connected with the injection port. 8. The porous medium flow reaction visualization system according to claim 7, characterized in that: the gas tank is connected to a parallel high-pressure dryer and a high-pressure humidifier through a tee, and the pipelines at both ends of the gas tank and all A valve is respectively provided on the pipelines at both ends of the high-pressure dryer and the high-pressure humidifier; distilled water or formation water is provided in the liquid tank, and CO ₂ is provided in the gas tank. 9. The porous media flow reaction visualization system according to claim 1, characterized in that: the collection mechanism includes a water collector and a dryer arranged in sequence, and the end of the water collector outlet pipe is located on the water collection On the top of the dryer, a flow meter is connected behind the dryer, and the flow meter is communicatively connected with the computer. 10. The porous media flow reaction visualization system according to claim 1, characterized in that: the camera system includes a digital microscope, a light source and a camera, the digital microscope is arranged above the transparent window, and the digital microscope is arranged below the transparent window. A light source, the camera is used to capture images observed by the digital microscope, and the camera is communicatively connected to the computer.