Experimental apparatus and method for simulating ultra-deep carbonate rock karst corrosion

Abstract

This invention provides an experimental apparatus and method for simulating ultra-deep carbonate karst corrosion. The apparatus includes: at least two reactors arranged in series, each reactor comprising a confining pressure mechanism and an axial pressure mechanism. The confining pressure mechanism has a core cavity for accommodating the core and is capable of applying confining pressure to the core. The axial pressure mechanism is used to apply axial pressure to the core in the core cavity and is provided with a reaction solution interface communicating with the core cavity; a solution pressure vessel system capable of providing a reaction solution and injecting it into the core cavity through the reaction solution interface; at least two back pressure control devices, with the outlet end of the core cavity of each reactor connected to the back pressure control device; and a detection system. The core cavities of the reactors are connected in series, and the reaction solution provided by the solution pressure vessel system can flow sequentially through the connected core cavities. The detection system is used to detect each core cavity separately, solving the technical problem of difficulty in simulating ultra-deep, strongly modified carbonate karst corrosion at depths of tens of thousands of meters.

Description

Technical Field

[0001] This invention relates to the field of petroleum and natural gas geology, and in particular to an experimental apparatus and method for simulating ultra-deep carbonate rock karstification. Background Technology

[0002] With the exploitation and depletion of shallow and medium-depth (depth < 4500m) oil and gas resources, the search for oil and gas resources in deep layers (depth 4500-6000m) and even ultra-deep layers (depth > 6000m) has become a realistic need and an important trend in oil and gas exploration.

[0003] However, ultra-deep carbonate rocks have complex geological conditions, low levels of understanding, and great exploration difficulties. Therefore, the formation mechanism and distribution pattern of ultra-deep carbonate rock reservoirs have become key scientific issues that need to be addressed in oil and gas exploration.

[0004] Water-rock reaction simulation experiments are an important method for studying the mechanism of carbonate rock dissolution. By setting different experimental conditions, the carbonate rock dissolution process under temperature, pressure and fluid control can be reproduced, thus providing a basis for identifying the laws of carbonate rock dissolution and predicting favorable reservoir development areas.

[0005] Chinese invention patent application CN102435716A discloses a diagenetic simulation experimental device, and Chinese invention patent application CN104407118A discloses an analytical method for the dissolution of carbonate rocks and its benefits. These methods enable the simulation of internal rock dissolution experiments using actual rock plunger samples. Their advantage lies in the fact that the water-rock ratio and hydrodynamic mode during the experiment closely resemble underground conditions, and they can analyze the evolution of internal pores in the rock before and after dissolution. However, dolomite samples exhibit complex and diverse pore types, including intercrystalline pores, oolitic pores, caverns, and fissures. During dissolution, the pore structure often changes, forming dominant channels for fluid transport. This alters the contact area between the fluid and the rock, leading to a decrease in the amount of rock dissolution. This inevitably affects the accurate understanding of the effects of temperature, pressure, and fluid factors on dissolution. Furthermore, the water-rock reaction data for dolomite lack repeatability and reproducibility.

[0006] Chinese invention patent application CN105137033A discloses a method and apparatus for quantitatively evaluating the surface karst effect in gypsum-carbonate rock reservoirs. However, this method only focuses on the karst erosion effect and quantitative evaluation of gypsum-carbonate rocks in the surface environment and is not applicable to the high-temperature and high-pressure conditions of water-rock reaction in dolomite during the burial stage. Although it considers the influence of gypsum-salt components in rock samples on dissolution, it ignores the formation water properties. However, dolomite is widely present in the formation, and fluid properties are the key factors affecting the dissolution and precipitation of dolomite. The method of immersing rock samples in a solution does not conform to the actual underground conditions in terms of water-rock ratio and hydrodynamic mode, and the chemical connotation represented by the amount of rock dissolution is unclear.

[0007] Chinese invention patent CN106323812B (patent number: CN201510387709.6) discloses a test device for water-rock simulated flow experiments, including a control unit; a reaction vessel with multiple sample tubes inside; and a constant flow pump, which includes multiple piston cylinders, multiple reversing units, and a drive mechanism. This device can simultaneously conduct multiple sets of water-rock simulated flow control experiments, ensuring that multiple rock samples react with the reaction liquid under the same test conditions. However, the device has shortcomings: the artificially prepared CO2 fluid, acetic acid fluid, and H2S solution react with the rock in the simulation experiment, without considering the need for underground fluids to cross different strata and the changes in fluid properties during transport; the fluid entering the reaction vessel to react with the rock is only driven by the constant flow pump, without distinguishing the type of fluid driving force, and cannot objectively simulate diagenetic processes such as dissolution, cementation, or replacement between the fluid and the reservoir under geological boundary conditions.

[0008] Subsurface carbonate rocks are widely distributed, and the reaction between carbonate rocks and acidic fluids quickly reaches chemical equilibrium.

[0009] Yang Yunkun et al. (A Re-understanding of Deep Dissolution of Carbonate Rocks Based on In-situ Observation of Simulation Experiments [J], Journal of Peking University (Natural Science Edition), 2014, 50(2): 316-322) Based on this, they designed a set of water-rock interaction simulation experiments for carbonate rocks with increasing burial depth using diamond cavity (DAC) technology. Although obvious cementation (precipitation) can be observed in situ, the amount of dissolution in the water-rock reaction of carbonate rocks cannot be quantitatively analyzed, and the specific role of formation water properties in the water-rock reaction process of dolomite cannot be analyzed.

[0010] Fan Ming et al. (The effect of acidic fluids on the modification of carbonate reservoirs [J], Geochemistry, 2009, 38(1): 20-26) designed a carbonate dissolution rate measuring instrument. However, this experimental device and method are dedicated to evaluating the dissolution rate of carbonate rocks, requiring the carbonate rock-water reaction results to be far from chemical equilibrium. Due to the small amount of rock sample, the fluid generated by the reaction still has the ability to react with the rock.

[0011] Based on the current state of research both domestically and internationally, carbonate rock dissolution simulation experimental devices can be divided into rock surface dissolution and rock internal dissolution according to the water-rock reaction mechanism. Rock surface dissolution experimental devices mainly include acid-rock reaction rotating rock disk apparatus, high-temperature and high-pressure tubular flow reaction device, diamond pressure chamber and molten capillary silica tube; rock internal dissolution experimental devices include high-temperature and high-pressure core seepage simulation device.

[0012] It is evident that rock surface dissolution experiments primarily utilize rock particles or blocks, with water-rock reactions mainly occurring on the rock surface, exhibiting a "water-encased rock" characteristic. The water-rock ratio and hydrodynamic conditions differ significantly from the burial environment, focusing mainly on the chemical reactions in carbonate rock water-rock reaction experiments. However, as some geologists have questioned the porosity-enhancing effects of burial dissolution in carbonate reservoirs, arguing that the chemical mechanism of carbonate rocks dissolving and enlarging porosity with acidic fluids is undeniable, the questions remain: what is the mechanism by which acidic fluids retain their acidity during long-distance migration? What is the scale of porosity-enhancing effects from burial dissolution? What are the dominant controlling factors and distribution patterns of favorable burial dissolution? Therefore, carbonate rock burial dissolution cannot be simplified to a chemical reaction. Instead, we must focus on the core geological question of the formation mechanism and distribution patterns of ultra-deep carbonate reservoirs, conducting carbonate rock dissolution simulation experiments under geological model constraints from a geological system perspective.

[0013] From the current technological standpoint, although the existing equipment cannot meet the needs of China's ultra-deep-strong modified carbonate karst erosion simulation experiments, the aforementioned experimental equipment has laid a solid foundation for the development of ultra-deep carbonate karst erosion simulation experimental devices through long-term research and accumulation.

[0014] Currently, previous carbonate rock dissolution simulation experiments have mostly focused on burial depths shallower than 6000 meters, and the experimental fluids are mainly organic acid solutions. Systematic simulation experiments on carbonate rock dissolution in ultra-deep (burial depth > 6000 m) and strongly altered geological settings have not yet been conducted. The mineral dissolution-precipitation mechanisms and their reservoir-forming effects in ultra-deep burial environments remain unclear. For example, can carbonate rocks undergo large-scale dissolution in ultra-deep environments? Can deep-source hydrothermal fluids improve reservoir performance? How can we quantitatively simulate the evolution of the dynamic process of carbonate rock dissolution increasing porosity and cementing decreasing porosity, and its main controlling factors? Can corrosive fluids retain acidity during long-distance migration across tectonic periods?

[0015] These mechanistic issues are the focus and challenge of research on the formation mechanism and distribution law of ultra-deep carbonate reservoirs. Consequently, higher requirements are placed on the simulation experimental device for carbonate rock dissolution under the coupled effects of ultra-deep temperature-stress-fluid. It must not only meet the requirements of higher working temperature, pressure and corrosion resistance, but also achieve necessary functions such as close to the geological reality of water-rock ratio and hydrodynamic mode, quantitative evaluation of dissolution porosification effect, characterization of the dynamic evolution process of rock internal pore structure under dissolution-precipitation, fluid migration across tectonic periods, and in-situ analysis of high-temperature and high-pressure fluid properties.

[0016] In summary, existing technologies make it difficult to conduct simulation experiments on the karstification of ultra-deep carbonate rocks with strong alteration at depths of tens of thousands of meters. Summary of the Invention

[0017] The purpose of this invention is to provide an experimental apparatus and method for simulating the karstification of ultra-deep carbonate rocks, so as to solve the technical problem that it is difficult to conduct simulation experiments on the karstification of ultra-deep carbonate rocks with strong alteration at depths of tens of thousands of meters in the prior art.

[0018] The above-mentioned objectives of the present invention can be achieved by the following technical solutions:

[0019] This invention provides an experimental apparatus for simulating ultra-deep carbonate karst corrosion, comprising:

[0020] At least two reactors arranged in series, each reactor including a confining pressure mechanism and an axial pressure mechanism, the confining pressure mechanism having a core cavity for accommodating a core and being able to apply confining pressure to the core, the axial pressure mechanism being used to apply axial pressure to the core in the core cavity, and the axial pressure mechanism being provided with a reaction solution interface communicating with the core cavity;

[0021] A solution pressure vessel system capable of providing a reaction solution and injecting it into the core cavity via the reaction solution interface;

[0022] At least two back pressure control devices are provided, and the outlet end of the core chamber of each of the reactors is connected to the back pressure control device.

[0023] Detection system;

[0024] The core chambers of the reactor are connected in series, and the reaction solution provided by the solution pressure vessel system can flow sequentially through the core chambers connected in series. The detection system is used to detect each of the core chambers separately.

[0025] In a preferred embodiment, the detection system includes at least two in-situ window detection mechanisms, each including a high-temperature and high-pressure fluid in-situ detection cell and a spectrometer. The high-temperature and high-pressure fluid in-situ detection cell is connected in series between the outlet end of the core cavity and the back pressure control device.

[0026] In a preferred embodiment, the high-temperature and high-pressure fluid in-situ detection pool includes a solution chamber, a fixing mechanism, and a window. The solution chamber is fixed between the outlet end of the core cavity and the back pressure control device by the fixing mechanism. The solution chamber is provided with a solution inlet and a solution outlet. The solution inlet is connected to the outlet end of the core cavity, and the solution outlet is connected to the back pressure control device. The window is provided in the solution chamber, and the spectrometer is provided outside the window. Light in the solution chamber can be transmitted to the spectrometer through the window.

[0027] In a preferred embodiment, the window portion includes a metal cylinder, a heat-insulating ceramic sleeve, and sapphire glass. The heat-insulating ceramic sleeve and the sapphire glass are respectively disposed at both ends of the metal cylinder. Furthermore, the sapphire glass has a large-diameter portion and a small-diameter portion, with the small-diameter portion being at least partially inserted into the metal cylinder.

[0028] In a preferred embodiment, the detection system includes pressure detection mechanisms corresponding to the reactors one-to-one; the pressure detection mechanism includes an inlet pressure sensor, an outlet pressure sensor, and a differential pressure sensor, the inlet pressure sensor being disposed at the inlet end of the core cavity, the outlet pressure sensor being disposed at the outlet end of the core cavity; the differential pressure sensor being disposed between the inlet end and the outlet end of the core cavity to detect the fluid pressure difference between the inlet end and the outlet end.

[0029] In a preferred embodiment, the back pressure control device includes a back pressure controller and a back pressure pump, the back pressure pump being connected to the back pressure controller, and the back pressure controller being located between the inlet end of the next core cavity and the high-temperature and high-pressure fluid in-situ detection pool.

[0030] In a preferred embodiment, the confining pressure mechanism includes a copper sleeve and a support sleeve. The inner cavity of the copper sleeve forms the core cavity. The support sleeve wraps around the outside of the copper sleeve. The support sleeve is provided with a confining pressure fluid channel. The confining pressure fluid enters between the support sleeve and the copper sleeve through the confining pressure fluid channel so that the copper sleeve applies confining pressure to the core.

[0031] In a preferred embodiment, the confining pressure fluid channel is connected to a confining pressure pump, which is used to deliver confining pressure fluid to the confining pressure fluid channel.

[0032] In a preferred embodiment, the confining pressure pump and the back pressure pump are connected to the same water container.

[0033] In a preferred embodiment, the reactor includes a temperature controller for regulating the temperature of the confining fluid.

[0034] In a preferred embodiment, the axial pressure mechanism includes hydraulic push rod type plugs disposed at both ends of the copper sleeve, and the reaction solution interface is disposed at the hydraulic push rod type plugs.

[0035] In a preferred embodiment, the solution pressure vessel system includes a pressure vessel, a gas cylinder, a gas booster pump, a gas flow meter, a gas buffer tank, and a dual-plunger pump. The gas booster pump is connected to the pressure vessel, and the gas cylinder, the gas booster pump, the gas buffer tank, and the gas flow meter are connected in series to the pressure vessel. The pressure vessel is connected to the reaction solution interface.

[0036] In a preferred embodiment, the detection system includes an electronic balance; a sampler is connected to the end of all the reactors connected in series, and the sampler is mounted on the electronic balance.

[0037] This invention provides a method for simulating ultra-deep carbonate rock karst corrosion, using the aforementioned ultra-deep carbonate rock karst corrosion simulation experimental apparatus. The experimental method includes:

[0038] The reactor applies confining pressure and axial pressure to the core in the core cavity;

[0039] The solution pressure vessel system provides the reaction solution and injects it into the core cavity, and the back pressure control device controls the outlet pressure of each core cavity;

[0040] The detection system performs detection on each of the core cavities.

[0041] The features and advantages of this invention are:

[0042] In this ultra-deep carbonate rock karstification simulation experimental device, multiple reaction vessels are arranged in series. The reaction solution provided by the solution pressure vessel system flows sequentially through the rock cores in each reaction vessel. The back pressure control device independently controls the fluid pressure in each reaction vessel. The confining pressure mechanism and axial pressure mechanism in each reaction vessel apply confining pressure and axial pressure to the rock core, respectively, thereby simultaneously loading the rock core with simulated static rock pressure and fluid pressure. This drives the fluid to cross two or more reaction vessels under different temperature and pressure conditions, realizing the simulation of carbonate rock karstification across tectonic periods under geological model constraints. It conducts multi-stage continuous flow simulation, which is beneficial to meeting the needs of ultra-deep and strongly modified carbonate rock karstification simulation experiments. Attached Figure Description

[0043] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0044] Figure 1 A schematic diagram of the overall experimental device for simulating ultra-deep carbonate rock karstification provided by the present invention;

[0045] Figure 2 for Figure 1 The diagram shows the pipeline connections of a single reactor in the ultra-deep carbonate karstification simulation experimental device.

[0046] Figure 3 for Figure 1 The diagram shows the pipeline connections of multiple reaction vessels in the ultra-deep carbonate karstification simulation experimental device.

[0047] Figure 4 for Figure 1 A schematic diagram of the solution pressure vessel system in the ultra-deep carbonate rock karstification simulation experimental device shown;

[0048] Figure 5 A schematic diagram of another embodiment of the solution pressure vessel system in the ultra-deep carbonate rock karstification simulation experimental device provided by the present invention;

[0049] Figure 6 A schematic diagram of the high-temperature and high-pressure fluid in-situ detection pool in the ultra-deep carbonate rock karstification simulation experimental device provided by the present invention;

[0050] Figure 7 A top view of the high-temperature and high-pressure fluid in-situ detection pool in the ultra-deep carbonate karst erosion simulation experimental device provided by the present invention;

[0051] Figure 8 for Figure 7 A sectional view along line AA in the middle;

[0052] Figure 9 for Figure 7 A sectional view along the BB direction in the middle;

[0053] Figure 10 An explosion diagram of the window section in the ultra-deep carbonate rock karstification simulation experimental device provided by the present invention;

[0054] Figure 11 A schematic diagram of the reactor in the ultra-deep carbonate rock karstification simulation experimental device provided by the present invention;

[0055] Figure 12 An overall structural diagram of the ultra-deep carbonate rock karstification simulation experimental device provided by the present invention;

[0056] Figure 13 for Figure 12 The rear view of the simulation experimental apparatus for ultra-deep carbonate rock karstification shown.

[0057] Explanation of icon numbers:

[0058] 1. Reactor; 2. Core;

[0059] 161. Reactor lid; 162. Ultra-high pressure reactor body; 163. Self-sealing plug; 164. Reactor support;

[0060] 18. Temperature control box; 181. Tracking heating jacket;

[0061] 10. Confining pressure mechanism; 101. Core cavity; 11. Copper sleeve; 12. Support sleeve;

[0062] 121. Confining pressure fluid channel; 122. Confining pressure port; 13. Confining pressure pump; 131. Second valve; 132. Safety valve; 14. Temperature controller;

[0063] 151. First temperature probe; 152. Second temperature probe; 20. Axial pressure mechanism; 21. Hydraulic push rod type plug;

[0064] 22. Reaction solution interface; 221. Fluid inlet; 222. Fluid outlet;

[0065] 23. Sampler;

[0066] 30. Back pressure control device; 31. Back pressure controller; 32. Back pressure pump; 33. Water container;

[0067] 34. Back pressure buffer device;

[0068] 40. Solution pressure vessel system;

[0069] 41. Pressure vessel; 411. First valve; 42. Gas cylinder; 43. Gas booster pump; 44. Gas buffer tank; 45. Dual plunger pump;

[0070] 46. ​​Flow meter; 471. First safety valve; 472. Pressure reducing valve; 48. Air compressor;

[0071] 49. Pressure sensor;

[0072] 50. Detection system;

[0073] 51. Pressure detection mechanism; 511. Inlet pressure sensor; 512. Outlet pressure sensor; 513. Differential pressure sensor;

[0074] 52. Electronic balance;

[0075] 6. In-situ window testing agency;

[0076] 60. High-temperature and high-pressure fluid in-situ detection cell;

[0077] 61. Solution chamber; 611. Solution inlet; 612. Solution outlet;

[0078] 62. Window section; 621. Thermal insulation ceramic sleeve;

[0079] 63. Metal cylinder; 631. Metal nut; 632. First metal washer;

[0080] 64. Sapphire glass; 641. Large diameter section; 642. Small diameter section;

[0081] 651. Second metal washer; 652. Graphite washer; 653. Metal O-ring;

[0082] 66. Fixing mechanism; 661. Fixing frame; 662. Metal jacket; 663. Heat insulation sleeve;

[0083] 67. Spectrometer;

[0084] 71. Mounting bracket; 72. Control cabinet. Detailed Implementation

[0085] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0086] Option 1

[0087] This invention provides an experimental device for simulating ultra-deep carbonate rock karst corrosion, such as... Figures 1-11 As shown, the experimental apparatus includes: a solution pressure vessel system 40, a detection system 50, at least two reactors 1 arranged in series, and at least two back pressure control devices 30. The reactor 1 includes a confining pressure mechanism 10 and an axial pressure mechanism 20. The confining pressure mechanism 10 has a core cavity 101 for accommodating the core 2 and is capable of applying confining pressure to the core 2. The axial pressure mechanism 20 is used to apply axial pressure to the core 2 in the core cavity 101. The axial pressure mechanism 20 is provided with a reaction solution interface 22 that communicates with the core cavity 101. The solution pressure vessel system 40 is capable of providing a reaction solution and injecting it into the core cavity 101 through the reaction solution interface 22. The outlet end of the core cavity 101 of each reactor 1 is connected to the back pressure control device 30. The core cavities 101 of the reactor 1 are connected in series. The reaction solution provided by the solution pressure vessel system 40 can flow sequentially through the connected core cavities 101. The detection system 50 is used to detect each core cavity 101 separately.

[0088] In this ultra-deep carbonate rock karstification simulation experimental device, multiple reaction vessels 1 are arranged in series. The reaction solution provided by the solution pressure vessel system 40 flows sequentially through the rock core 2 in each reaction vessel 1. The back pressure control device 30 independently controls the fluid pressure in each reaction vessel 1. The confining pressure mechanism 10 and the axial pressure mechanism 20 in each reaction vessel 1 apply confining pressure and axial pressure to the rock core 2 respectively, thereby simultaneously loading the rock core 2 with simulated static rock pressure and fluid pressure. This device can drive the fluid across two or more temperature and pressure conditions in the reaction vessel 1, realize the simulation of carbonate rock karstification across tectonic periods under geological model constraints, and conduct multi-stage continuous flow simulation, which is beneficial to meeting the needs of ultra-deep and strongly modified carbonate rock karstification simulation experiments.

[0089] The ultra-deep carbonate karst erosion simulation experimental device provided by this invention can perform ultra-high temperature and high pressure triaxial stress clamping on the core through the reaction vessel 1. The solution pressure vessel system 40 can provide high saturated CO2 and realize multi-stage continuous flow reaction, thereby realizing high saturated CO2 erosion simulation. The detection system 50 can perform real-time online detection of ultra-high temperature and high pressure permeability and realize in-situ detection of high temperature and high pressure fluid composition and content. It provides an experimental device for ultra-deep temperature-stress-fluid coupling effect high temperature and high pressure carbonate karst erosion simulation experiment, so as to realize that ultra-deep oil and gas exploration is deep earth exploration and advanced support for the basic theoretical research of ultra-deep oil and gas exploration at 10,000 meters.

[0090] In one embodiment, the detection system 50 includes at least two in-situ window detection mechanisms 6. Each in-situ window detection mechanism 6 includes a high-temperature and high-pressure fluid in-situ detection cell 60 and a spectrometer 67. The high-temperature and high-pressure fluid in-situ detection cell 60 is connected in series between the outlet end of the core cavity 101 and the back pressure control device 30. The reaction solution flowing out of the core cavity 101 flows through the high-temperature and high-pressure fluid in-situ detection cell 60, and the spectrometer 67 performs in-situ detection on it, which can provide real-time continuous measurement of water-rock reaction products under different temperature and pressure conditions. For carbonate rock dissolution reactions, it is possible to use Raman spectroscopy to semi-quantitatively measure the amount of dissolution under equilibrium conditions in "in-situ," thereby comprehensively studying the dissolution / precipitation trend of carbonate rocks with increasing burial depth.

[0091] like Figure 2 , Figure 3 and Figure 6 As shown, the high-temperature and high-pressure fluid in-situ detection cell 60 includes a solution chamber 61, a fixing mechanism 66, and a window 62. The solution chamber 61 is fixed between the outlet end of the core chamber 101 and the back pressure control device 30 via the fixing mechanism 66. The solution chamber 61 is provided with a solution inlet 611 and a solution outlet 612. The solution inlet 611 is connected to the outlet end of the core chamber 101, and the solution outlet 612 is connected to the back pressure control device 30. The window 62 is provided in the solution chamber 61, and the spectrometer 67 is provided outside the window 62. Light in the solution chamber 61 can be transmitted to the spectrometer 67 through the window 62. The reaction solution flows into the solution chamber 61 through the solution inlet 611 and can flow to the next reaction vessel 1 through the solution outlet 612. The spectrometer 67 detects the reaction solution in the solution chamber 61 through the window 62. Preferably, the solution chamber 61 is made of hafnium alloy material, has a hollow structure, is used to contain the reaction product solution, and is externally connected to a thermocouple to control the temperature inside the chamber. like Figures 7-9 As shown, the two ends are connected to the pipelines of solution inlet 611 and solution outlet 612 by means of metal tapered threads, and the other two ends are connected to the window section 62, which are the signal source transmitter and the signal source receiver, respectively.

[0092] Furthermore, the window portion 62 includes a metal cylinder 63, a heat-insulating ceramic sleeve 621, and a sapphire glass 64. The heat-insulating ceramic sleeve 621 and the sapphire glass 64 are respectively disposed at both ends of the metal cylinder 63. The sapphire glass 64 has a large-diameter portion 641 and a small-diameter portion 642, with the small-diameter portion 642 at least partially inserted into the metal cylinder 63. The window portion 62 considers both pressure resistance and good spectral signal transmittance, improving the structural stability of the window portion 62. Light in the solution chamber 61 propagates to the spectrometer 67 through the sapphire glass 64, ensuring detection under high temperature and high pressure conditions. The sapphire glass 64 can be a nut-type sapphire glass 64. Specifically, the metal cylinder 63 includes a metal nut 631 and a first metal washer 632, with the first metal washer 632 disposed at one end of the metal nut 631; as... Figure 10 As shown, the window portion 62 also includes a second metal washer 651, a graphite washer 652, and a metal O-ring 653, with the second metal washer 651 disposed between the graphite washer 652 and the first metal washer 632.

[0093] like Figure 9 As shown, the fixing mechanism 66 includes a fixing frame 661, a metal jacket 662, and a heat insulation sleeve 663. The solution chamber 61 is fixed in place under high pressure by the fixing frame 661. The fixing frame 661 is wrapped with the heat insulation sleeve 663, which is made of fire-resistant and heat-insulating material for heat insulation and heat preservation. The metal jacket 662 is installed on the outside.

[0094] The high-temperature and high-pressure fluid in-situ detection cell 60 is connected to the spectrometer at both ends via fiber optic probes. The high-temperature and high-pressure fluid in-situ detection cell 60 can withstand high temperature and high pressure. The generated liquid from reactor 1 flows through the high-temperature and high-pressure fluid in-situ detection cell 60. The spectrometer can be used to analyze the composition and content of the generated liquid within the high-temperature and high-pressure fluid in-situ detection cell 60 under high-temperature and high-pressure in-situ conditions. The spectrometer 67 can be a laser Raman spectrometer.

[0095] In one embodiment, the detection system 50 includes a pressure detection mechanism 51 corresponding to the reaction vessel 1; such as Figure 1 and Figure 2As shown, the pressure detection mechanism 51 includes an inlet pressure sensor 511, an outlet pressure sensor 512, and a differential pressure sensor 513. The inlet pressure sensor 511 is located at the inlet end of the core chamber 101, and the outlet pressure sensor 512 is located at the outlet end of the core chamber 101. The differential pressure sensor 513 is located between the inlet and outlet ends of the core chamber 101 to detect the fluid pressure difference between the inlet and outlet ends. For each reactor 1, the fluid pressure at the inlet and outlet ends of the core chamber 101 is detected in real time through the inlet pressure sensor 511 and the outlet pressure sensor 512; and the fluid pressure difference between the inlet and outlet ends is detected in real time through the differential pressure sensor 513, thereby obtaining the fluid pressure at the inlet and outlet ends of the core 2 and its difference in real time.

[0096] Furthermore, the detection system 50 includes an electronic balance 52; samplers 23 are connected to the ends of all the reaction vessels 1 connected in series, and the samplers 23 are mounted on the electronic balance 52. The electronic balance 52 can record the fluid flow rate of the samplers 23 and collect the flow rate of the reaction-generated solution per unit time in real time.

[0097] Differential pressure sensor 513 directly measures the fluid pressure difference between the inlet and outlet ends of core 2, while inlet pressure sensor 511 and outlet pressure sensor 512 measure the fluid pressure at the inlet and outlet ends of core 2, respectively; the fluid pressure difference is then calculated; electronic balance records the fluid flow rate of sampler 23, and collects the flow rate of the reaction-generated solution per unit time in real time; according to Darcy's formula, the liquid permeability value of core 2 is calculated in real time, ultimately realizing the real-time online continuous measurement of the liquid permeability value of the rock plunger sample during the water-rock reaction process, and generating a real-time evolution characteristic curve of core 2 permeability through control software.

[0098] The control system can coordinate the various hardware mechanical structures and circuit systems in the detection system 50 through control software to achieve real-time online measurement of ultra-high temperature and high pressure permeability values. The software can also collect quantitative parameters of the connectivity properties of carbonate rocks during the dissolution process in real time and generate characteristic curves of the evolution of rock connectivity properties with reaction time during the dissolution process.

[0099] In one implementation, such as Figure 2 and Figure 3 As shown, the back pressure control device 30 includes a back pressure controller 31 and a back pressure pump 32. The back pressure pump 32 is connected to the back pressure controller 31, which is located between the inlet of the next core chamber 101 and the high-temperature, high-pressure fluid in-situ detection pool 60. The outlet of each reactor 1 controls the internal fluid pressure of the rock through the back pressure controller 31 and the back pressure pump 32, realizing multi-stage cross-tectonic period dissolution simulation. In another embodiment, as... Figure 5As shown, the back pressure control device 30 includes a back pressure controller 31, a back pressure pump 32, and a back pressure buffer device 34. The back pressure pump 32 is connected to the back pressure controller 31 through the back pressure buffer device 34. The back pressure controller 31 can specifically be a back pressure valve.

[0100] In one embodiment, the confining pressure mechanism 10 includes a copper sleeve 11 and a support sleeve 12. The inner cavity of the copper sleeve 11 forms a core cavity 101. The support sleeve 12 wraps around the copper sleeve 11 and is provided with a confining pressure fluid channel 121. The confining pressure fluid enters between the support sleeve 12 and the copper sleeve 11 through the confining pressure fluid channel 121, so that the copper sleeve 11 applies confining pressure to the core 2, enabling the core 2 to be clamped under high temperature and high pressure conditions. The confining pressure fluid channel 121 has a confining pressure port 122, such as... Figure 2 and Figure 11 As shown, the confining pressure fluid channel 121 is connected to the confining pressure pump 13, which is used to deliver confining pressure fluid to the confining pressure fluid channel 121.

[0101] Preferably, such as Figure 3 As shown, the confining pressure pump 13 and the back pressure pump 32 are connected to the same water container 33, which helps to simplify the structure of the experimental device and reduce operational failures.

[0102] Furthermore, the reactor 1 includes a temperature controller 14, which is used to regulate the temperature of the confining fluid, thereby controlling the ambient temperature around the core 2, simulating the high-temperature environment of the formation, which is beneficial for more direct and efficient control of temperature conditions and improving the accuracy of temperature control.

[0103] In one implementation, such as Figure 11 As shown, the axial pressure mechanism 20 includes hydraulic push rod type plugs 21 disposed at both ends of the copper sleeve 11, and the reaction solution interface 22 is disposed at the hydraulic push rod type plugs 21. The hydraulic push rod type plugs 21 can be controlled by the axial hydraulic control system of the reactor 1 to axially compress the core 2 in the core cavity 101, thereby providing axial pressure.

[0104] Reactor 1 functions as a high-temperature, high-pressure triaxial stress core holder. At least two reactors 1 are connected in series via pipelines. Each reactor 1 conducts water-rock reaction simulations under the corresponding tectonic period's diagenetic environment. Therefore, each reactor 1 is equipped with an independent temperature controller 14, confining pressure pump 13, back pressure controller 31, and back pressure pump 32. The temperature controller 14 controls the water-rock reaction temperature inside reactor 1, and the confining pressure pump 13 controls the confining pressure surrounding the core sample 2. At each stage, the outlet of reactor 1 is controlled by the back pressure controller 31 and back pressure pump 32 to control the internal fluid pressure of the rock, performing multi-stage continuous flow simulation. In the experiment simulating fluid dissolution across tectonic periods, by simulating the temperature, pressure, fluid chemical properties, mineral composition, and flow characteristics of different tectonic periods during diagenesis, it is possible to effectively simulate diagenetic processes such as dissolution, cementation, and metasomatism caused by changes in temperature, pressure, and fluid properties in actual strata due to basin tectonic activity. Figure 2 As shown, the outlet end of the confining pressure pump 13 is connected to a second valve 131 to control the start and stop of the delivery of confining pressure fluid; the confining pressure mechanism 10 is also connected to a safety valve 132.

[0105] The reactor 1 is an ultra-high temperature and high pressure triaxial stress reactor. This invention optimizes the structure of reactor 1 as follows: Figure 11 As shown, the reactor 1, from the outside to the inside, is equipped with a temperature control box 18, a reactor support 164, and an ultra-high pressure reactor body 162. It also includes a self-sealing plug 163 and a sample chamber fixing bracket 661. The ultra-high pressure reactor body 162 has a removable lid 161 at its top, containing a metal piston that divides it into upper and lower spaces. The upper space includes a fluid inlet 221, a fluid outlet 222, a confining pressure port 122, a first temperature probe 151, and a self-sealing plug 163. The lower space has a second temperature probe 152. The ultra-high pressure reactor body 162 includes a tracking heating jacket 181. The tracking heating jacket 181 and the two temperature probes are controlled by the temperature control box 18 to track the temperature of the core 2. Furthermore, the fluid inlet 221, the core chamber 101, and the fluid outlet 222 are connected.

[0106] The reaction solution interface 22 includes a fluid inlet 221 and a fluid outlet 222. The core 2 serves as the sample, and the core cavity 101 serves as the sample chamber. The copper sleeve 11 is preferably a hollow copper cylindrical sample tube, forming the main body of the sample chamber. The sample is placed inside the copper cylindrical sample tube, with hollow hydraulic push-rod plugs 21 placed at both ends. One end of the hydraulic push-rod plug 21 connects to the reaction solution inlet 611, and the other end connects to the reaction dissolution outlet. The support sleeve 12 is mainly used to protect the hollow copper cylindrical sample tube. The support sleeve 12 is an alloy cylinder composed of two pieces, wrapping around the outside of the hollow copper cylindrical sample tube. Each support sleeve 12 contains two circular holes, allowing confining fluid to pass through the support sleeve 12 to wrap around the hollow copper cylindrical sample tube and apply confining pressure. The confining fluid channel 121 communicates with these circular holes. Self-sealing plugs 163 are placed at both ends of the sample chamber to fix the support sleeve 12 and the hollow copper cylindrical sample tube; the sample chamber fixing bracket 661 is used to fix the sample chamber to the high-temperature and high-pressure resistant chamber sealing cap to ensure the sample chamber is fixed under high temperature and high pressure conditions. One end of the sample chamber fixing bracket 661 is connected to the self-sealing plug 163, and the other end is fixed to the sample chamber by screws; the ultra-high pressure vessel body 162 is hollow and can bear the confining pressure fluid, and is equipped with electric heating and temperature thermocouples to provide the temperature for the water-rock reaction in the sample chamber by heating the confining pressure fluid; the confining pressure port 122 is connected to the confining pressure pump and the pressure control system.

[0107] In one embodiment, the solution pressure vessel system 40 includes a pressure vessel 41, a gas cylinder 42, a gas booster pump 43, a gas buffer tank 44, a gas flow meter 46, and a dual-plunger pump 45. The gas booster pump 43 is connected to the pressure vessel 41. The gas cylinder 42, gas booster pump 43, gas buffer tank 44, and gas flow meter 46 are connected in series to the pressure vessel 41. The pressure vessel 41 is connected to the reaction solution interface 22. The pressure vessel 41 can be a piston container, the dual-plunger pump 45 can be a constant-speed, constant-pressure pump, and the gas cylinder 42 can store CO2. The solution pressure vessel system 40 can quantitatively prepare a highly saturated CO2 solution, simulating the composition of CO2-rich hydrothermal fluids deep within the Earth, and achieving simulation of highly saturated CO2 dissolution. The various hardware mechanical structures in the solution pressure vessel system 40 can be coordinated and controlled by a host computer control software.

[0108] like Figure 4 As shown, the gas booster pump 43 is connected to the air compressor 48, the pressure reducing valve 472 is connected in series between the gas buffer tank 44 and the gas flow meter 46, a first safety valve 471 is installed between the gas booster pump 43 and the gas buffer tank 44, and a first valve 411 is connected to the outlet of the solution pressure vessel system 40. Figure 5 As shown, a pressure sensor 49 is also connected to the outlet of the solution pressure vessel system 40.

[0109] like Figure 12 and Figure 13As shown, the reactor 1, solution pressure vessel system 40, and in-situ viewing window detection mechanism 6 are mounted on the mounting frame 71 and electrically connected to the control cabinet 72 for coordinated control of each component.

[0110] The ultra-deep carbonate karst erosion simulation experimental device provided by this invention can realize the simulation of carbonate karst erosion under the coupled action of temperature-stress-fluid. It simulates the water-rock reaction under the combined control of temperature-stress-fluid in geological backgrounds from near the surface to 10,000 meters deep, and solves the technical problem of difficulty in simulating the karst erosion of 10,000-meter ultra-deep and strongly modified carbonate rocks in the prior art.

[0111] Option 2

[0112] This invention provides a method for simulating carbonate karst corrosion using the aforementioned ultra-deep carbonate karst corrosion simulation experimental apparatus. The experimental method includes: applying confining pressure and axial pressure to the core 2 in the core cavity 101 using a reaction vessel 1; providing a reaction solution and injecting it into the core cavity 101 using a solution pressure vessel system 40; controlling the outlet pressure of each core cavity 101 using a back pressure control device 30; and detecting each core cavity 101 using a detection system 50. This experimental method possesses the technical features and beneficial effects of the aforementioned experimental apparatus, which will not be elaborated further here.

[0113] This experimental method enables seepage simulation of ultra-deep, ultra-high temperature and high pressure core samples (up to 10,000 meters deep). It involves developing ultra-high temperature and high pressure triaxial stress clamping, automatic confining pressure tracking control, in-situ ultra-high temperature and high pressure observation, real-time online measurement of ultra-high temperature and high pressure permeability, automatic back pressure tracking, and quantitative metering and delivery of saturated CO2. These systems are integrated and coordinated to achieve the functional requirements of ultra-high temperature and high pressure core sample seepage simulation, multi-stage continuous flow simulation, real-time online detection of ultra-high temperature and high pressure permeability, in-situ detection of high-temperature and high-pressure fluid composition and content, and high-saturation CO2 dissolution simulation. The upper-computer control software in the software control system completes the control of experimental parameters, data acquisition, spectrum analysis, and evaluation for each unit.

[0114] The carbonate karst corrosion simulation experimental method provided by this invention has the following characteristics:

[0115] (1) Simulation of the water-rock reaction environment in ultra-deep carbonate rocks at a depth of 10,000 meters:

[0116] It provides simulation of ultra-deep (ten thousand meters) geological environments, tectonic-fluid interactions, and continuous rock-fluid chemical reactions under large-span temperature and pressure conditions, such as a maximum working temperature of 450℃ and a maximum working pressure of 150MPa. Core 2 is simultaneously loaded to simulate static rock pressure and fluid pressure, and can drive fluid across two or more temperature and pressure conditions in reactor 1, realizing the simulation of carbonate rock dissolution across tectonic periods under geological model constraints.

[0117] (2) Quantitative evaluation of the reservoir-forming effect of dissolution and characterization of pore structure evolution:

[0118] The test provides two core plunger samples for simulation experiments. The porosity, permeability and weight parameters before and after the experiment can be used to quantitatively evaluate the pore-forming effect of dissolution on the rock. The CT analysis before and after the experiment can be used to characterize the dynamic evolution of the internal pore structure of the rock under dissolution through in-situ comparison.

[0119] (3) Quantitative characterization of connectivity evolution during rock dissolution:

[0120] It provides real-time online measurement of ultra-high temperature and high pressure permeability values, and the software collects quantitative parameters of the connectivity properties of carbonate rocks in real time during the dissolution process, generating characteristic curves of the evolution of rock connectivity properties with reaction time during the dissolution process.

[0121] (4) Real-time measurement of fluid composition and content during rock dissolution:

[0122] It provides real-time, continuous measurement of water-rock reaction products under different temperature and pressure conditions. For carbonate rock dissolution reactions, it can realize in-situ semi-quantitative measurement of dissolution under equilibrium conditions using Raman spectroscopy, and thus comprehensively study the dissolution / precipitation trend of carbonate rocks with increasing burial depth.

[0123] The above descriptions are merely a few embodiments of the present invention. Those skilled in the art can make various modifications or variations to the embodiments of the present invention based on the content disclosed in the application documents without departing from the spirit and scope of the present invention.

Claims

1. A simulation experimental device for ultra-deep carbonate rock karst corrosion, characterized in that, include: At least two reactors arranged in series, each reactor including a confining pressure mechanism and an axial pressure mechanism, the confining pressure mechanism having a core cavity for accommodating a core and being able to apply confining pressure to the core, the axial pressure mechanism being used to apply axial pressure to the core in the core cavity, and the axial pressure mechanism being provided with a reaction solution interface communicating with the core cavity; A solution pressure vessel system capable of providing a reaction solution and injecting it into the core cavity via the reaction solution interface; At least two back pressure control devices are provided, and the outlet end of the core chamber of each of the reactors is connected to the back pressure control device. Detection system; The core chambers of the reactor are connected in series, and the reaction solution provided by the solution pressure vessel system can flow sequentially through the core chambers connected in series. The detection system is used to detect each of the core chambers separately. The detection system includes at least two in-situ window detection mechanisms, each including a high-temperature and high-pressure fluid in-situ detection cell and a spectrometer. The high-temperature and high-pressure fluid in-situ detection cell is connected in series between the outlet end of the core cavity and the back pressure control device. The high-temperature and high-pressure fluid in-situ detection pool includes a solution chamber, a fixing mechanism, and a window. The solution chamber is fixed between the outlet end of the core chamber and the back pressure control device by the fixing mechanism. The solution chamber is provided with a solution inlet and a solution outlet. The solution inlet is connected to the outlet end of the core chamber, and the solution outlet is connected to the back pressure control device. The window is disposed in the solution cavity, and the spectrometer is disposed outside the window. Light from the solution cavity can propagate to the spectrometer through the window. The window section includes a metal O-ring, sapphire glass, graphite gasket, second metal gasket, metal cylinder and heat-insulating ceramic sleeve arranged from left to right. The heat-insulating ceramic sleeve and the sapphire glass are respectively disposed at both ends of the metal cylinder. The sapphire glass has a large diameter portion and a small diameter portion, and the small diameter portion is at least partially inserted into the metal cylinder. The metal cylinder includes a metal nut and a first metal washer. The first metal washer is disposed at one end of the metal nut, the heat-insulating ceramic sleeve is disposed at the other end of the metal nut, and the second metal washer is disposed between the graphite washer and the first metal washer.

2. The experimental apparatus for simulating ultra-deep carbonate karst corrosion according to claim 1, characterized in that, The detection system includes pressure detection mechanisms corresponding to each of the reaction vessels; The pressure detection mechanism includes an inlet pressure sensor, an outlet pressure sensor, and a differential pressure sensor. The inlet pressure sensor is located at the inlet end of the core cavity, and the outlet pressure sensor is located at the outlet end of the core cavity. The differential pressure sensor is located between the inlet and outlet ends of the core cavity to detect the fluid pressure difference between the inlet and outlet ends.

3. The experimental apparatus for simulating ultra-deep carbonate karst corrosion according to claim 2, characterized in that, The detection system includes an electronic balance; a sampler is connected to the end of all the reactors connected in series, and the sampler is mounted on the electronic balance.

4. The experimental apparatus for simulating ultra-deep carbonate karst corrosion according to claim 1, characterized in that, The back pressure control device includes a back pressure controller and a back pressure pump. The back pressure pump is connected to the back pressure controller, and the back pressure controller is located between the inlet end of the next core chamber and the high-temperature and high-pressure fluid in-situ detection pool.

5. The experimental apparatus for simulating ultra-deep carbonate karst corrosion according to claim 4, characterized in that, The confining pressure mechanism includes a copper sleeve and a support sleeve. The inner cavity of the copper sleeve forms the core cavity. The support sleeve wraps around the outside of the copper sleeve. The support sleeve is provided with a confining pressure fluid channel. The confining pressure fluid enters between the support sleeve and the copper sleeve through the confining pressure fluid channel so that the copper sleeve applies confining pressure to the core.

6. The experimental apparatus for simulating ultra-deep carbonate karst corrosion according to claim 5, characterized in that, The confining pressure fluid channel is connected to a confining pressure pump, which is used to deliver confining pressure fluid to the confining pressure fluid channel.

7. The experimental apparatus for simulating ultra-deep carbonate karst corrosion according to claim 6, characterized in that, The confining pressure pump and the back pressure pump are connected to the same water container.

8. The experimental apparatus for simulating ultra-deep carbonate karst corrosion according to claim 5, characterized in that, The reactor includes a temperature controller, which is used to regulate the temperature of the confining fluid.

9. The experimental apparatus for simulating ultra-deep carbonate karst corrosion according to claim 5, characterized in that, The axial pressure mechanism includes hydraulic push rod type plugs disposed at both ends of the copper sleeve, and the reaction solution interface is disposed at the hydraulic push rod type plugs.

10. The experimental apparatus for simulating ultra-deep carbonate karst corrosion according to claim 1, characterized in that, The solution pressure vessel system includes a pressure vessel, a gas cylinder, a gas booster pump, a gas flow meter, a gas buffer tank, and a dual-plunger pump. The gas booster pump is connected to the pressure vessel. The gas cylinder, the gas booster pump, the gas buffer tank, and the gas flow meter are connected in series to the pressure vessel. The pressure vessel is connected to the reaction solution interface.

11. A method for simulating ultra-deep carbonate rock karst corrosion, characterized in that, The experimental apparatus for simulating ultra-deep carbonate karst corrosion according to any one of claims 1-10, wherein the experimental method includes: The reactor applies confining pressure and axial pressure to the core in the core cavity; The solution pressure vessel system provides the reaction solution and injects it into the core cavity, and the back pressure control device controls the outlet pressure of each core cavity; The detection system performs detection on each of the core cavities.

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