An experimental device and method for simulating water-rock reaction at reservoir pore scale

Abstract

The application provides a water-rock reaction simulation experiment device and method under reservoir pore scale, the device comprises a reaction generation system, a pressure control system, a temperature control system and an optical observation system which operate in cooperation, wherein the reaction generation system provides a reservoir pore simulation space for reaction generation and facilitates real-time observation, the temperature control system creates a suitable temperature environment for the reaction generation system during the reaction process, the pressure control system provides a reaction pressure for simulating the reservoir pore environment, and the user can observe the reaction state and data of sample materials under the reservoir porosity condition in real time by means of the optical observation system, the problem of insufficient analysis process integrity in the prior art is overcome, the influence of sample transfer on the experiment state is avoided, the understanding of the development mechanism and conditions of the dissolution type reservoir can be effectively deepened, and the reservoir quality research and improvement work in the oil and gas exploration project are facilitated.

Description

Technical Field

[0001] This invention relates to the field of oil and gas exploration geological reservoir research technology, and in particular to an experimental apparatus and method for simulating water-rock reaction at the reservoir pore scale. Background Technology

[0002] In oil and gas exploration, the principle of improving reservoir quality is as follows: through the exchange of matter and energy, the reservoir rocks are dissolved and replaced, altering the reservoir's pore structure and permeability, thereby effectively improving reservoir quality and forming eroded reservoirs. Dissolved reservoirs are an important type of high-quality reservoir in oil and gas basins, especially given the current global trend of oil and gas exploration extending to deeper and ultra-deep (>4500 meters) layers. As reservoir burial deepens, primary porosity almost disappears, and secondary dissolved pores often become the main reservoir space.

[0003] A key and core aspect of studying the development mechanism of dissolution reservoirs is the research on water-rock reaction processes and mechanisms, and simulation experiments based on reasonable systems and environments are an effective research method. However, water-rock reaction processes in oil and gas reservoirs occur at the rock pore scale, while for conventional oil and gas reservoirs, the interaction space is often at the micrometer scale. Therefore, conventional simulation experimental devices and methods for oil and gas reservoirs cannot effectively present information on water-rock reaction processes and mechanisms. Consequently, there is a need for experimental methods and devices capable of simulating fluid-rock interactions at the micrometer scale. Summary of the Invention

[0004] To address the above problems, the present invention provides an experimental apparatus for simulating water-rock reaction at the reservoir pore scale. In one embodiment, the apparatus includes:

[0005] The reaction generation system provides a reservoir porosity simulation space for the target reaction solution and mineral materials to undergo reactions and facilitate real-time observation;

[0006] A pressure control system, which is connected to the reaction system, is configured to control the operating status of relevant valves, pipelines and instruments to provide a reaction pressure that simulates the reservoir pore environment for the target reaction solution and mineral materials.

[0007] A temperature control system, including a sample stage, creates a temperature environment that meets experimental requirements for the reaction system set on the sample stage during the reaction process;

[0008] An optical observation system, positioned above the temperature control system, presents the real-time status data of the target reaction solution and mineral materials to the user.

[0009] In a preferred embodiment, the apparatus further includes:

[0010] The spectroscopic analysis system, located above the temperature control system, acquires and analyzes the spectral information of the target reaction solution and mineral materials during the reaction process, and generates spectral analysis results.

[0011] Furthermore, in one embodiment, the reservoir pore simulation space provided by the reaction system includes a transparent capillary quartz tube and an extension tube, wherein one end of the transparent capillary quartz tube is sintered and sealed as a reaction chamber, and the other end is open;

[0012] One end of the extension tube is open, and the other end is sealed to a valve of the pressure control system.

[0013] During the reaction, the open end of the transparent capillary quartz tube is sealed and nested with the open end of the extension tube.

[0014] In one embodiment, the pressure control system includes a pressure pump and a pressure gauge containing a pressure sensor. Both the pressure gauge and the pressure pump are connected to the extension tube of the reaction system through a first valve, a second valve, and multiple pipelines to ensure the smooth pressurization of experimental samples and related reagents and to achieve dual regulation of the experimental process, thereby controlling the abnormal reaction rate and operational error rate of the experiment.

[0015] Specifically, in one embodiment, the temperature control system employs a hot and cold stage with an opening on the side of the hot and cold stage, allowing the transparent capillary quartz tube of the reaction system to extend into the hot and cold stage during the reaction and be placed in the groove of the sample stage inside the hot and cold stage. The upper and lower parts of the groove are covered with a transparent protective layer to maintain a stable temperature environment for the transparent capillary quartz tube.

[0016] Furthermore, the top and bottom surfaces of the heating and cooling platform are both open in the areas perpendicular to the reaction chamber, and are filled with transparent sealing sheets.

[0017] In one embodiment, the optical observation system is positioned directly above the transparent sealing sheet and employs a long working distance objective microscope to avoid accidental contact with the hot or cold stage during observation.

[0018] Specifically, the spectroscopic analysis system includes a laser, an optical objective, an intermediate component, and a spectrometer. The laser emitted by the laser is refracted by the first intermediate component and then acts on the reaction cavity.

[0019] The reflected light from the reaction chamber is refracted by the second and third intermediate components and then fed back to the spectrometer;

[0020] The spectrometer is a microconfocal Raman spectrometer, which identifies the absorption information of spectral signals by the capillary quartz tube body and each transparent protective sheet and sealing sheet, and combines the absorption information to achieve accurate analysis of spectral signals during the reaction process.

[0021] Based on other aspects of any one or more embodiments of the present invention described above, the present invention also provides a method for simulating water-rock reaction at the reservoir pore scale, the method comprising:

[0022] Step S210: Start the temperature control system to ensure that the sample stage temperature meets the set reaction temperature conditions.

[0023] Step S220: Place the target reaction solution and mineral materials into the reaction generating system and return them to the reaction chamber position;

[0024] Step S230: Use the pressure control system to provide the reservoir pore pressure required for the reaction to the reaction system;

[0025] Step S240: Observe and record the state data of the target reaction solution and mineral materials in real time through an optical observation system.

[0026] Furthermore, in one embodiment, the method further includes:

[0027] Step S310: Use a spectroscopic analysis system to acquire and analyze the spectral information of the target reaction solution and the mineral materials during the reaction process, and generate spectral analysis results.

[0028] Step S220 includes the following operations:

[0029] The target reaction solution and mineral materials are placed into the open end, so that they are both located in the reaction chamber of the welded end of the transparent capillary quartz tube;

[0030] The reaction solution was blocked using a sealing material that met the experimental requirements;

[0031] After injecting pure water, the transparent capillary quartz tube is sealed and nested with the extension tube at a predetermined distance from the open end.

[0032] Compared with the closest prior art, the present invention also has the following beneficial effects:

[0033] This invention provides an experimental apparatus and method for simulating water-rock reaction at the reservoir porosity scale. A reaction generation system provides a reservoir porosity simulation space for real-time observation of the reaction. During the reaction, a temperature control system and a pressure control system create a simulated temperature and pressure environment for the reaction under reservoir porosity conditions. Only an optical observation system is needed to allow users to observe the reaction state and data of the sample material under reservoir porosity conditions in real time. There is no need to transfer the reaction sample before observation, avoiding the impact of sample transfer on the experimental state and eliminating the "black box" bottleneck in analysis during the transfer process. This reduces operational complexity while improving the reliability and authenticity of experimental data, providing reliable experimental theory and data basis for predicting the development mechanism and distribution of dissolution-type reservoirs.

[0034] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures particularly pointed out in the description, claims, and drawings. Attached Figure Description

[0035] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with the embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:

[0036] Figure 1 This is a schematic diagram of the structure of a water-rock reaction simulation experimental device at the reservoir pore scale provided in an embodiment of the present invention;

[0037] Figure 2 This is a schematic diagram of the material SN structure of a water-rock reaction simulation experimental device at the reservoir pore scale provided in another embodiment of the present invention.

[0038] Figure 3 This is a schematic flowchart of the water-rock reaction simulation experiment method at the reservoir pore scale provided in the embodiments of the present invention;

[0039] Figure 4 This is a schematic flowchart of a water-rock reaction simulation experiment method at the reservoir pore scale provided in another embodiment of the present invention; Attached image description:

[0041] (1) is a transparent capillary quartz tube, (2) is a pressure control system, (3) is a temperature control system, (4) is an optical observation system, and (5) is a spectroscopic analysis system. Detailed Implementation

[0042] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings and examples. Those skilled in the art will then fully understand how the present invention uses technical means to solve technical problems and achieve technical effects, and will be able to implement the present invention specifically based on the above-described implementation process. It should be noted that, as long as there is no conflict, the various embodiments and features of the present invention can be combined with each other, and the resulting technical solutions are all within the protection scope of the present invention.

[0043] Although the flowchart describes the operations as sequential processes, many of these operations can be performed in parallel, concurrently, or simultaneously. The order of the operations can be rearranged. A process can terminate when its operation is complete, but it may also have additional steps not included in the diagram. A process can correspond to a method, function, procedure, subroutine, subroutine, etc.

[0044] Computer equipment includes user equipment and network equipment. User equipment or clients include, but are not limited to, computers, smartphones, PDAs, etc.; network equipment includes, but is not limited to, a single network server, a server group consisting of multiple network servers, or a cloud based on cloud computing consisting of a large number of computers or network servers. Computer equipment can operate independently to implement this invention, or it can connect to a network and implement this invention through interaction with other computer equipment in the network. The network in which the computer equipment is located includes, but is not limited to, the Internet, wide area network, metropolitan area network, local area network, VPN network, etc.

[0045] The terms “first,” “second,” etc., may be used herein to describe various units, but these units should not be limited by these terms; they are used merely to distinguish one unit from another. The term “and / or” as used herein includes any and all combinations of one or more of the associated listed items. When a unit is referred to as “connected” or “coupled” to another unit, it may be directly connected or coupled to said other unit, or there may be intermediate units present.

[0046] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments. Unless the context clearly indicates otherwise, the singular forms “a” and “an” as used herein are also intended to include the plural. It should also be understood that the terms “comprising” and / or “including” as used herein specify the presence of the stated features, integers, steps, operations, units, and / or components, without excluding the presence or addition of one or more other features, integers, steps, operations, units, components, and / or combinations thereof.

[0047] In oil and gas exploration, the principle of improving reservoir quality is as follows: through the exchange of matter and energy, the reservoir rocks are dissolved and replaced, altering the reservoir's pore structure and permeability, thereby effectively improving reservoir quality and forming eroded reservoirs. Dissolved reservoirs are an important type of high-quality reservoir in oil and gas basins, especially given the current global trend of oil and gas exploration extending to deeper and ultra-deep (>4500 meters) layers. As reservoir burial deepens, primary porosity almost disappears, and secondary dissolved pores often become the main reservoir space.

[0048] A key and core aspect of studying the development mechanism of dissolution reservoirs is the research on water-rock reaction processes and mechanisms, and simulation experiments based on reasonable systems and environments are an effective research method. However, water-rock reaction processes in oil and gas reservoirs occur at the rock pore scale, while for conventional oil and gas reservoirs, the interaction space is often at the micrometer scale. Therefore, conventional simulation experimental devices and methods for oil and gas reservoirs cannot effectively present information on water-rock reaction processes and mechanisms. Consequently, there is a need for experimental methods and devices capable of simulating fluid-rock interactions at the micrometer scale.

[0049] To overcome the aforementioned shortcomings, the researchers of this invention have dedicated themselves to developing an experimental apparatus suitable for highly realistic simulation of water-rock reaction processes. During a survey of other simulation experimental techniques in the field, it was found that water-rock reaction simulation experiments can be divided into two categories based on different analytical methods: offline observation and online observation. Due to the specific requirements of the experimental environment for water-rock simulation reactions, offline observation involves controlling the sample under certain temperature and pressure conditions for a period of time, then adjusting the sample temperature to room temperature, and taking out the fluid and rock samples for separate testing. Online analysis, on the other hand, allows for real-time, continuous, in-situ analysis of the composition and structure of the fluid and rock under the reaction temperature and pressure conditions during the experiment. Considering that the reaction vessels for offline analysis are mostly various types of high-pressure reactors, primarily made of metal, and with dimensions mostly in the millimeter or even centimeter range—at least 1 to 2 orders of magnitude larger than the pore space of conventional oil and gas reservoirs—they cannot accurately simulate the water-rock reaction process at the pore scale. Furthermore, while the initial and final states of the sample are clear during offline observation experiments, the intermediate states of the reaction are unknown, creating a "black box" bottleneck in process analysis and failing to comprehensively present valuable experimental data regarding the water-rock reaction process.

[0050] Based on this, the present invention provides a water-rock reaction simulation experimental device at the reservoir pore scale, equipped with a transparent reaction chamber with a micron-sized diameter. During the experiment, the phase state and composition of the fluid and minerals in the reaction can be observed and analyzed in real time as needed, so as to reliably reveal the dissolution mechanism and conditions of reservoir minerals. This helps to provide data basis for reservoir analysis and exploitation scheme design in oil and gas exploration engineering.

[0051] The following is a detailed description of the method according to an embodiment of the present invention, based on the accompanying drawings. The steps shown in the flowcharts can be executed in a computer system containing, for example, a set of computer-executable instructions. Although the logical order of the steps is shown in the flowcharts, in some cases, the steps shown or described may be performed in a different order than that shown here.

[0052] Example 1

[0053] Figure 1This diagram illustrates the structure of the water-rock reaction simulation experimental device at the reservoir pore scale provided in Embodiment 1 of the present invention. (Refer to...) Figure 1 It can be seen that the device includes the following structure:

[0054] The reaction generation system provides a reservoir porosity simulation space for the target reaction solution and mineral materials to undergo reactions and facilitate real-time observation;

[0055] A pressure control system, which is connected to the reaction system, is configured to control the operating status of relevant valves, pipelines and instruments to provide a reaction pressure that simulates the reservoir pore environment for the target reaction solution and mineral materials.

[0056] A temperature control system, including a sample stage, creates a temperature environment that meets experimental requirements for the reaction system set on the sample stage during the reaction process;

[0057] An optical observation system, positioned above the temperature control system, presents the real-time status data of the target reaction solution and mineral materials to the user.

[0058] In one embodiment, the reservoir pore simulation space provided by the reaction system includes a transparent capillary quartz tube and an extension tube, wherein one end of the transparent capillary quartz tube is sintered and sealed as a reaction chamber, and the other end is open;

[0059] One end of the extension tube is open, and the other end is sealed to a valve of the pressure control system.

[0060] In practical applications, the specifications of the transparent capillary quartz tube used are: inner diameter 100-200 micrometers, outer diameter 600-800 micrometers, and length 20-30 centimeters. The extension tube is made of stainless steel with specifications of inner diameter 800-1000 micrometers, outer diameter 1400-1600 micrometers, and length 3-5 centimeters.

[0061] Specifically, one end of the transparent capillary quartz tube is sintered and sealed with an oxyhydrogen flame. In application, the mineral material and the target reaction solution are sealed into the quartz tube and the sealing end is welded. Then, the reaction solution is plugged with silicone oil or mercury, and pure water is injected from the open end of the quartz tube (the silicone oil or mercury column is located between the reaction solution and the pure water). The mineral material is usually processed into tiny mineral particles.

[0062] During the reaction, the open end of the transparent capillary quartz tube is sealed and nested with the open end of the extension tube. In practical applications, after pure water is injected from the open end of the quartz tube, resin is used to fix the portion of the capillary quartz tube, approximately 3-5 cm from the open end, to the inner wall of the stainless steel tube to achieve a sealed nested connection.

[0063] In one embodiment, the pressure control system includes a pressure pump and a pressure gauge containing a pressure sensor. Both the pressure gauge and the pressure pump are connected to the extension tube of the reaction system through a first valve 21, a second valve 22, and multiple pipelines to ensure the smooth pressurization of experimental samples and related reagents and to achieve dual regulation of the experimental process, thereby controlling the abnormal reaction rate and operational error rate of the experiment.

[0064] Specifically, the pressure control system mainly consists of two valves, stainless steel pipelines, pressure sensors and pressure gauges, and a booster pump.

[0065] When conducting a simulation experiment using the device of the present invention, the transparent capillary quartz tube of the reaction system is connected to a valve in the pressure control system via an extension tube. A stainless steel pipeline is provided between the first valve and the second valve. At the same time, the pressure gauge and the pressure pump are both connected to the second valve via the stainless steel pipeline. In this embodiment of the invention, the use of stainless steel pipelines in the pressure control system can effectively withstand high pressure, reduce the component failure rate, and control the probability of experimental abnormalities.

[0066] During the experiment, the pressure of the sample in the reaction chamber was controlled by a pressurizing pump by squeezing water into the closed reaction system. The pressure applied varied depending on the experimental subject.

[0067] The pressure inside the closed pipe is equal, and its value is read by pressure sensors and pressure gauges connected to the reaction system.

[0068] Secondly, in order to connect the pressure pump water injection device and pressure gauge, the embodiments of the present invention are equipped with multiple valves. Different valves play the role of controlling the connection between different pipelines. When all valves are open at the same time, the operation of the pressure pump will affect the reaction state. At the same time, setting multiple valves and stainless steel pipelines of a set length can also ensure the smoothness of the experimental sample pressurization process and the orderly control and placement of the experimental device, control the abnormal reaction rate and operation error rate of the experiment, and optimize the space occupancy rate of the device.

[0069] Furthermore, in one embodiment, the temperature control system employs a hot-cold stage with openings on its side, allowing the transparent capillary quartz tube of the reaction system to extend into the hot-cold stage and be placed within a groove in the sample stage inside the hot-cold stage. The upper and lower parts of the groove are covered with transparent protective layers to maintain a stable temperature environment for the transparent capillary quartz tube. The top and bottom surfaces of the hot-cold stage, corresponding perpendicularly to the reaction chamber, are open and filled with transparent sealing sheets.

[0070] In practical applications, the temperature control system mainly consists of a heating and cooling stage with an opening on the side to allow the welded end of the capillary quartz tube to extend into the heating and cooling stage. The diameter of this opening should be slightly larger than the outer diameter of the transparent capillary quartz tube to prevent a large amount of external air from entering the heating and cooling stage and affecting the temperature stability.

[0071] The temperature control system heats the sample stage within the hot and cold stage using resistance wires, controlling the sample temperature through the principle of thermal radiation. A groove is cut into the sample stage to accommodate a capillary quartz tube. The lower and upper parts of the capillary tube within the groove are covered with quartz or glass plates to maintain a uniform sample temperature. Openings are required on the top and bottom surfaces of the hot and cold stage corresponding to the sample positions within the reaction chamber, and these openings are sealed with quartz or glass plates to allow laser, reflected, and transmitted light to pass through the entire hot and cold stage, facilitating optical observation and spectroscopic analysis.

[0072] In an optional embodiment, the temperature control system further includes a temperature sensor and a temperature display module connected to the temperature sensor. The temperature sensor monitors the temperature information within the hot and cold stages in real time, transmits the temperature information to the temperature display module for analysis and calculation, and outputs corresponding temperature display data. The temperature display data includes real-time temperature data and adjustment suggestions. To ensure the authenticity and comprehensiveness of the collected temperature data, the number of temperature sensors can be set according to the experimental requirements and the volume of the hot and cold stages.

[0073] In one embodiment, the optical observation system is positioned directly above the transparent sealing sheet and mainly consists of an optical microscope. Specifically, it employs a long working distance objective microscope to avoid accidental contact with the hot or cold stage during observation.

[0074] Laser Raman spectroscopy is a non-destructive micro-area analysis method. Gases, liquids, and various solid samples can be used for Raman spectroscopy measurements without special treatment, and it does not affect the reaction sample or reaction state, resulting in highly reliable analytical results. Therefore, in an optional embodiment, the device further includes:

[0075] The spectroscopic analysis system, positioned above the temperature control system, acquires and analyzes the spectral information of the target reaction solution and mineral materials during the reaction process, generating spectral analysis results, such as... Figure 2 As shown.

[0076] Specifically, in one embodiment, the spectroscopic analysis system includes a laser, an optical objective, an intermediate component, and a spectrometer. The laser emitted by the laser is refracted by the first intermediate component 51 and then acts on the reaction cavity through the optical objective. In actual operation, the optical objective can share a single objective with the optical observation system under experimentally permissible conditions.

[0077] The reflected light from the reaction chamber is refracted by the second intermediate component 52 and the third intermediate component 53 and then fed back to the spectrometer;

[0078] The spectrometer is a microconfocal Raman spectrometer, which identifies the absorption information of spectral signals by the capillary quartz tube body and each transparent protective sheet and sealing sheet, and combines the absorption information to achieve accurate analysis of spectral signals during the reaction process.

[0079] Considering the presence of multiple layers of quartz or glass plates on the hot and cold stages and the sample stage, as well as the absorption of spectral signals by the capillary quartz tube itself, this embodiment of the invention uses a microconfocal Raman spectrometer for real-time analysis of the sample composition. The microconfocal Raman spectrometer has extremely high spectral and spatial resolution, effectively identifying and eliminating the influence of quartz or glass plates on the analysis.

[0080] In addition, after the experiment is completed, the sample can be removed and analyzed and tested using appropriate offline analysis methods.

[0081] The water-rock reaction simulation experimental device provided in this embodiment of the invention includes a capillary quartz tube reaction chamber, a temperature control system, a pressure control system, and an online optical and spectroscopic observation system, etc., to simulate the interaction process between minerals and hydrothermal fluids in oil and gas reservoirs. Specifically, it can not only simulate the water-rock reaction process of experimental samples in the reservoir pore scale environment, but also, due to the use of in-situ observation technology, can conduct real-time and continuous online observation and analysis of the water-rock reaction process, thereby deepening the understanding of the development mechanism and conditions of dissolution reservoirs, providing basic experimental and theoretical basis for the development mechanism and distribution prediction of dissolution reservoirs, breaking through the "black box" bottleneck of experimental analysis, and significantly improving the integrity and authenticity of experimental data.

[0082] In the water-rock reaction simulation experimental device at the reservoir pore scale provided in this embodiment of the invention, each module or unit structure can operate independently or in combination according to experimental and analytical needs to achieve the corresponding technical effects.

[0083] Example 2

[0084] The apparatus has been described in detail in the embodiments disclosed above. Based on other aspects of the apparatus described in any one or more of the above embodiments, the present invention also provides a method for simulating water-rock reaction at the reservoir pore scale. This method is used to simulate water-rock reaction based on the water-rock reaction simulation apparatus at the reservoir pore scale described in any one or more of the above embodiments. Specific embodiments are given below for detailed description.

[0085] Specifically, Figure 3The diagram shows a schematic flowchart of the water-rock reaction simulation experiment method at the reservoir pore scale provided in an embodiment of the present invention. Figure 3 As shown, the method includes:

[0086] Step S310: Start the temperature control system to ensure that the sample stage temperature meets the set reaction temperature conditions.

[0087] Step S320: Place the target reaction solution and mineral materials into the reaction chamber of the reaction system;

[0088] Step S330: Use the pressure control system to provide the reservoir pore pressure required for the reaction to the reaction system;

[0089] Step S340: Observe and record the state data of the target reaction solution and mineral materials in real time through an optical observation system.

[0090] Laser Raman spectroscopy is a non-destructive micro-area analysis method. Gases, liquids, and various solid samples can be used for Raman spectroscopy determination without special treatment, and it does not affect the reaction sample or reaction state, resulting in highly reliable analytical results. Therefore, in an optional embodiment, the method further includes: step S410, acquiring and analyzing the spectral information of the target reaction solution and mineral materials during the reaction process using a spectroscopic analysis system to generate spectral analysis results, such as... Figure 4 As shown.

[0091] Specifically, in one embodiment, step S320 includes the following operations:

[0092] The target reaction solution and mineral materials are placed into the open end, so that they are both located in the reaction chamber of the welded end of the transparent capillary quartz tube;

[0093] The reaction solution was blocked using a sealing material that met the experimental requirements;

[0094] After injecting pure water, the transparent capillary quartz tube is sealed and nested with the extension tube at a predetermined distance from the open end.

[0095] To more comprehensively and clearly illustrate the execution flow of the water-rock reaction simulation experiment method in the embodiments of the present invention, the following uses a special silicified rock reservoir developed in the Ordovician Yingshan Formation limestone strata in the Shuntogole area of ​​the Tarim Basin as an example to illustrate the specific process of performing the water-rock reaction simulation experiment method on the reservoir using the scheme of the embodiments of the present invention.

[0096] In the Ordovician Yingshan Formation limestone strata of the Shuntogole area in the Tarim Basin, a unique silicified rock reservoir has developed. This reservoir is formed by the dissolution of limestone and precipitation of quartz by silica-rich hydrothermal fluids transported from deep within the formation along faults, resulting in numerous intercrystalline pores in the quartz. Below the Yingshan Formation, the Ordovician Penglaiba Formation and the Cambrian strata are mainly composed of dolomite. The reaction mechanism between dolomite and silica-rich hydrothermal fluids is unclear, and whether effective reservoirs can be formed lacks experimental verification.

[0097] In summary, typical dolomite core samples from the Penglaiba Formation in the Shuntogole area of ​​the Tarim Basin were selected as the target ore material, and silicate and deionized water were used as the target reactant solutions. The experimental analysis was conducted according to the following steps:

[0098] (1) Place dolomite powder, silicic acid, and deionized water into the reaction chamber of a capillary quartz tube. Use excess silicic acid to ensure the solution is saturated with silicon. In practice, the amount of the target reaction solution should be prepared according to the actual experimental reaction requirements.

[0099] (2) Separate the reaction solution and the pressure medium (pure water) with mercury or silicone oil, and then fix a 3-5 cm long section of the capillary quartz tube reaction chamber opening into the inside of the stainless steel tube. Let it stand for 12 hours, and then connect it to the pressure control system through a valve.

[0100] (3) Place the hot and cold stage on the microscope stage and insert the sample section of the capillary quartz tube into the hot and cold stage in order to control the uniformity of the sample reaction temperature.

[0101] (4) Use a pressure pump to control the sample pressure and adjust the pressure to the set value of 500 bar.

[0102] (5) Increase the sample temperature to 200℃.

[0103] (6) Use a microscope to observe the morphology of powder samples and the changes in fluid phase, such as whether bubbles emerge in the solution.

[0104] (7) The spectra of solid and fluid samples were collected every 30 minutes using an in-situ Raman spectroscopy system. CO2 was detected in the gas phase component, indicating that the dolomite underwent a decarbonization reaction under the action of silicon-rich fluid.

[0105] (8) Analyze the change of CO2 signal intensity with reaction time. When the signal intensity no longer changes with time, it indicates that the reaction has reached equilibrium.

[0106] (9) Change the sample temperature and pressure, repeat steps 6 to 8, and clarify the temperature and pressure conditions of the reaction.

[0107] (10) After the experiment was completed, the capillary quartz tube was removed, and micro-area X-ray diffraction analysis was performed on the solid phase components to further investigate the changes in mineral phases. It was found that in addition to the reactant dolomite, magnesium-rich silicate minerals, such as talc, were also formed.

[0108] (11) Determine the reaction equation based on the results of Raman spectroscopy and X-ray diffraction analysis.

[0109] (12) Compare the changes in the molar volume of minerals before and after the reaction to determine whether the reaction produces residual space and whether the reaction increases reservoir porosity and improves reservoir rock permeability, thereby determining whether silica-rich fluids can improve the physical properties of dolomite reservoirs.

[0110] In this embodiment of the invention, a capillary quartz tube reaction chamber is used. Its inner diameter is close to that of conventional oil and gas reservoir pores, both being in the micrometer range. It is also transparent to light, allowing for optical observation and spectroscopic analysis. Through a conventional hot and cold stage and pressure control system, the sample temperature and pressure can be controlled in real time, and real-time observation of the sample phase and reaction process under experimental temperature and pressure conditions can be achieved.

[0111] For the foregoing method embodiments, in order to simplify the description, they are all described as a series of actions. However, those skilled in the art should understand that the present invention is not limited to the described order of actions, because according to the present invention, some steps can be performed in other orders or simultaneously. Furthermore, those skilled in the art should also understand that the embodiments described in the specification are preferred embodiments, and the actions and modules involved are not necessarily essential to the present invention.

[0112] It should be noted that, in other embodiments of the present invention, the method can also combine one or more of the above embodiments to obtain a new water-rock reaction simulation experimental method at the reservoir pore scale, so as to achieve effective analysis of the mineral dissolution mechanism and conditions of oil and gas reservoirs.

[0113] It should be noted that, based on the methods in any one or more embodiments of the present invention described above, the present invention also provides a storage medium storing program code that can implement the methods described in any one or more embodiments. When the program code is executed by the operating system, it can implement the water-rock reaction simulation experimental method at the reservoir pore scale as described above.

[0114] It should be understood that the embodiments disclosed herein are not limited to the specific structures, processing steps, or materials disclosed herein, but should be extended to equivalent substitutions of these features as understood by those skilled in the art. It should also be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting.

[0115] The phrase "an embodiment" in the specification means that a specific feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the invention. Therefore, the phrase "an embodiment" appearing in various places throughout the specification does not necessarily refer to the same embodiment.

[0116] While the embodiments disclosed in this invention are as described above, the content is merely for the purpose of facilitating understanding of the invention and is not intended to limit the invention. Any person skilled in the art to which this invention pertains may make any modifications and variations in form and detail of the implementation without departing from the spirit and scope disclosed herein; however, the scope of patent protection for this invention shall still be determined by the scope defined in the appended claims.

Claims

1. A water-rock reaction simulation experimental device at the reservoir pore scale, characterized in that, The device includes: The reaction generation system provides a reservoir porosity simulation space for the target reaction solution and mineral materials to undergo reaction and facilitate real-time observation; A pressure control system, which is connected to the reaction system, is configured to control the working status of relevant valves, pipelines and instruments to provide the target reaction solution and mineral materials with a reaction pressure that simulates the reservoir pore environment. A temperature control system, including a sample stage, creates a temperature environment that meets experimental requirements for the reaction system set on the sample stage during the reaction process. An optical observation system, which is located above the temperature control system, presents the real-time status data of the target reaction solution and mineral materials to the user. The spectroscopic analysis system, located above the temperature control system, acquires and analyzes the spectral information of the target reaction solution and mineral materials during the reaction process, and generates spectral analysis results. The reservoir pore simulation space provided by the reaction system includes a transparent capillary quartz tube and an extension tube. One end of the transparent capillary quartz tube is sintered and sealed to serve as a reaction chamber, while the other end is open. The configuration is such that, during the experiment, the ore material and the target reaction solution are sent into the transparent capillary quartz tube and the end is welded and sealed. The reaction solution is then blocked with silicone oil or mercury, and pure water is injected through the open end of the quartz tube. The silicone oil or mercury column is located between the reaction solution and the pure water. One end of the extension tube is open, and the other end is sealed to a valve of the pressure control system. The extension tube is made of stainless steel; the open end of the transparent capillary quartz tube is sealed and nested with the open end of the extension tube; after pure water is injected from the open end of the quartz tube, resin is used to fix the part of the capillary quartz tube at a set length from the open end to the inner wall of the stainless steel extension tube to achieve a sealed nested connection. The pressure control system includes a pressure pump and a pressure gauge containing a pressure sensor. Both the pressure gauge and the pressure pump are connected to the stainless steel extension tube of the reaction system through a first valve, a second valve, and multiple pipelines to ensure the smooth pressurization of the experimental samples and related reagents and to achieve dual regulation of the experimental process, thereby controlling the abnormal reaction rate and operational error rate of the experiment. The pressure pump squeezes water into the closed reaction system to control the pressure of the sample in the reaction chamber.

2. The apparatus as claimed in claim 1, characterized in that, The temperature control system employs a hot and cold stage with openings on its side, allowing the transparent capillary quartz tube of the reaction system to extend into the hot and cold stage and be placed in the groove of the sample stage inside the hot and cold stage. The upper and lower parts of the groove are covered with transparent protective layers to maintain a stable temperature environment for the transparent capillary quartz tube.

3. The apparatus as described in claim 2, characterized in that, The top and bottom surfaces of the heating and cooling platforms are open in areas perpendicular to the reaction chamber and are filled with transparent sealing sheets.

4. The apparatus as claimed in claim 1, characterized in that, The optical observation system is positioned directly above the transparent sealing sheet and uses a long working distance objective microscope to avoid accidental contact with the hot or cold stage during observation.

5. The apparatus as claimed in claim 1, characterized in that, The spectroscopic analysis system includes a laser, an optical objective, an intermediate component, and a spectrometer. The laser emitted by the laser is refracted by the first intermediate component and then acts on the reaction cavity. The reflected light from the reaction chamber is refracted by the second and third intermediate components and then fed back to the spectrometer; The spectrometer is a microconfocal Raman spectrometer, which identifies the absorption information of spectral signals by the capillary quartz tube body and each transparent protective sheet and sealing sheet, and combines the absorption information to achieve accurate analysis of spectral signals during the reaction process.

6. A method for simulating water-rock reaction at the reservoir pore scale, characterized in that, The method is applied to the water-rock reaction simulation experimental apparatus at the reservoir pore scale as described in any one of claims 1 to 5, and the method includes: Step S210: Start the temperature control system to ensure that the sample stage temperature meets the set reaction temperature conditions. Step S220: Place the target reaction solution and mineral materials into the reaction generating system and return them to the reaction chamber position; Step S230: Use the pressure control system to provide the reservoir pore pressure required for the reaction to the reaction system; Step S240: Observe and record the state data of the target reaction solution and mineral materials in real time through an optical observation system.

7. The method as described in claim 6, characterized in that, The method further includes: Step S310: Use a spectroscopic analysis system to acquire and analyze the spectral information of the target reaction solution and the mineral materials during the reaction process, and generate spectral analysis results.

8. The method as described in claim 6, characterized in that, Step S220 includes the following operations: The target reaction solution and mineral materials are placed into the open end, so that they are both located in the reaction chamber of the welded end of the transparent capillary quartz tube; The reaction solution was blocked using a sealing material that met the experimental requirements; After injecting pure water, the transparent capillary quartz tube is sealed and nested with the extension tube at a predetermined distance from the open end.

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