Fluid and rock interaction reaction kettle under true biaxial stress

Abstract

The invention relates to the field of petroleum experimental equipment, and discloses a reaction kettle for interaction of fluid and rock under true biaxial stress. The reaction kettle comprises a reaction shell and four flow field adjusting mechanisms, the reaction shell is provided with two through holes, a cavity is formed at the joint of the two through holes, and the two through holes are divided into four insertion holes by the cavity; a flow field adjusting mechanism is inserted into each inserting hole and comprises a pressing rod and a flow dividing assembly, a plurality of flow dividing holes are formed in the flow dividing assembly, a flow guiding hole is formed in the pressing rod, the side face of the flow dividing assembly is closed, and a sealing assembly is arranged between the pressing rod and the inner wall of the inserting hole. The reaction kettle provided by the invention is matched with corresponding equipment for use, and can realize analog simulation research on temperature, time, static rock pressure, fluid pressure, confining pressure, fluid medium, formation pore space and true biaxial rock mechanics under deep-deep and ultra-deep conditions of a petroliferous basin at the same time; therefore, accurate model evaluation parameters of the interaction between the deep formation fluid and the rock are obtained.

Description

Technical Field

[0001] The invention relates to the field of petroleum experimental equipment, in particular to a fluid and rock interaction reactor under true biaxial stress. Background Art

[0002] In recent years, research on the formation mechanisms, hydrocarbon generation evolution, quantitative evaluation, and potential prediction of oil and gas under deep, high-temperature, and high-pressure environments has gradually become a hot topic in conventional oil and gas exploration and development. Numerous research results have also revealed that the influence of static rock pressure and fluid pressure on oil and gas generation and evolution cannot be ignored, and the coupling relationship between these two factors, along with temperature and time, is a key factor controlling organic matter maturation and hydrocarbon generation. At the same time, the unconventional oil and gas sector also faces significant challenges due to the strong heterogeneity of tight source rocks, large stress anisotropy, and significant heterogeneity in fluid composition. In fact, hydrocarbon generation and diagenesis are a mutually reinforcing and organically integrated system. By artificially simulating the interaction between fluids and rocks in the laboratory, the heterogeneity of tight sandstones and shales can be evaluated, which is also of great significance for predicting the geometric morphology of hydraulic fracturing fractures and studying the connectivity and conductivity of bedding fractures.

[0003] The rapid development of big data and artificial intelligence technologies has driven the emergence of a large number of new petroleum experimental technologies, new scientific research instruments and equipment, and new data analysis methods. This has also forced the development of non-standard experimental equipment towards standardization, automation, and intelligence. The demand for refined, efficient, and streamlined analysis of experimental results and data mining is also increasing. With the continuous advancement of fluid-rock interaction research, simulation of real-world subsurface conditions is gradually evolving from single instruments to comprehensive experimental platforms. Traditional fluid-rock interaction reactors are diverse and their implementation methods vary significantly. The fundamental premise of these reactors is to assume that the rock sample is an internally homogeneous and unoriented porous medium. This idealized model is suitable for comparing simulation results between multiple, widely dissimilar source rock samples, but it is difficult to meet the requirements for in-depth studies of the internal composition, material structure, and stress and strain of highly similar source rocks.

[0004] In this regard, Chinese utility model patent CN2718566Y discloses a new type of autoclave, comprising a lid, a body, and an inlet and outlet mechanism. The body is a U-shaped cup with a sealed bottom (volume approximately 250 mL). A rotating flange and polytetrafluoroethylene (PTFE) static seal are used between the top and lid. During the experiment, the source rock sample is crushed to 200 mesh and placed in the autoclave. High-pressure water (typically less than 10 MPa) is introduced into the autoclave, and the body is placed in a heating furnace (250-550°C, temperature step 50°C). After heating at a specific heating rate, the gaseous products are collected through the inlet and outlet mechanism, and the lid is opened to remove the solid and liquid products. However, with this design, the fluid in the "U"-shaped autoclave can directly contact and react with the sample. However, the sealing scheme of the rotating flange and polytetrafluoroethylene means that the fluid pressure inside the pressure vessel is unlikely to exceed 10 MPa. The overall temperature increase of the autoclave also poses significant technical challenges to the sealing conditions. The inability to directly simulate real static rock pressure and control the inflow and outflow of materials is a significant technical drawback.

[0005] Chinese invention patent CN101231279A discloses a high-temperature, high-pressure thermal simulation experiment combining a gold tube with an autoclave. Before the experiment, a source rock sample and a reaction fluid are mixed and placed in a gold tube (40 mm long, 4 mm diameter, 0.2 mm thick) sealed at one end. The other end is sealed by welding under argon protection. The gold tube is then placed in a high-pressure reactor. High-pressure water is injected into the reactor to apply pressure (typically 10 to 70 MPa) to the outer wall of the tube. This pressure is transferred to the sample itself by leveraging the chemical inertness and ductility of gold. During the experiment, the high-pressure reactor is heated in a high-temperature furnace at varying heating rates (typically 2°C / h or 20°C / h) to a series of target temperatures (200 to 650°C). After the experiment, the reactor is removed from the furnace, allowed to cool naturally, and the pressure released. The reactor is then opened to remove the gold tube, which is then punctured using a screw-in valve needle under vacuum to quantify the experimental product within the tube and conduct subsequent analytical testing. The biggest advantage of this high-pressure autoclave plus gold tube reactor combination is that it can simulate external confining pressure, but it is also a strictly closed system and cannot study the intermediate processes of water-rock interaction.

[0006] Deep and ultra-deep oil and gas resources vary in temperature and pressure fields, tectonic evolution, sedimentary sources, burial rates, physical property distributions, and preservation conditions across different regions. This makes it crucial to more precisely evaluate the heterogeneity, stress anisotropy, and fluid composition heterogeneity during fluid-rock interactions. In summary, existing reactors suffer from a mismatch between simulation conditions and actual geological conditions, low overall control system accuracy, poor repeatability, and weak high-frequency continuous online observation capabilities. These issues make it difficult to meet the demand for simulation of high-temperature, high-pressure fluid-rock interactions in deep oil and gas basins, and they are unable to meet the requirements for more scientific, precise, and efficient technical specifications in the current context of refined exploration and development. Summary of the Invention

[0007] In order to solve the above technical problems or at least partially solve the above technical problems, the present invention provides a fluid-rock interaction reactor under true biaxial stress.

[0008] The present invention provides a fluid-rock interaction reactor under true biaxial stress, comprising:

[0009] The reaction shell is provided with two through holes arranged in a cross manner, and the intersection of the two through holes forms a cavity for accommodating rock samples, and the cavity divides the two through holes into four insertion holes;

[0010] Four flow field regulating mechanisms, one of the flow field regulating mechanisms is inserted into each of the sockets, the flow field regulating mechanisms include a pressure rod and a diversion assembly arranged at the end of the pressure rod, a plurality of diversion holes are formed in the diversion assembly, the interior of the pressure rod is provided with a guide hole connected to the plurality of diversion holes, the end of the guide hole facing away from the diversion assembly is used to connect with the liquid supply pipeline, the diversion assembly is used to support the side of the rock sample, and the side of the diversion assembly not in contact with the rock sample is closed, and a sealing assembly is provided between the pressure rod and the inner wall of the socket.

[0011] Optionally, the diversion assembly includes a conical sintered plate, a plurality of diversion holes are arranged inside the sintered plate, the end face of the sintered plate is supported on the side of the rock sample, and the diversion assembly also includes a sealing block surrounding the outer periphery of the sintered plate, and the pressure rod abuts against the end face of the sealing block.

[0012] Optionally, a stabilizing ring is provided at one end of the pressure rod facing away from the diversion assembly. The stabilizing ring is coaxially arranged with the pressure rod, and a side wall of the stabilizing ring is provided with a first opening for the liquid supply pipe to pass through.

[0013] Optionally, the jack has a stepped surface, one end of the sealing assembly abuts against the stepped surface, and the other end of the sealing assembly is provided with a pressing assembly.

[0014] Optionally, the sealing assembly includes a sealing ring, a first copper sealing pressure ring, a graphite sealing pressure ring and a second copper sealing pressure ring which are sequentially arranged away from the step surface.

[0015] Optionally, a first annular protrusion is provided on a side of the sealing ring facing the first copper sealing pressure ring, and a first annular groove matching the first annular protrusion is provided on the first copper sealing pressure ring.

[0016] Optionally, the clamping assembly includes a pressure cap sleeved on the outer periphery of the pressure rod, a portion of the pressure cap extends into the socket and abuts against the side of the second copper sealing pressure ring, and another portion of the pressure cap is supported at the end of the socket.

[0017] Optionally, the clamping assembly further includes a limiting pressure ring sleeved on the outer periphery of the pressure rod, the limiting pressure ring abuts against the side of the pressure cap facing away from the second copper sealing pressure ring, and the limiting pressure ring is provided with a second opening for the liquid supply pipe to pass through.

[0018] Optionally, a second annular protrusion is provided on a side of the pressure cap facing the second copper sealing pressure ring, and a second annular groove matching the second annular protrusion is provided on the second copper sealing pressure ring.

[0019] Optionally, the reaction housing is in a cross structure, and the two through holes extend along two perpendicularly arranged symmetry axes of the reaction housing.

[0020] The technical solution provided by the embodiments of the present invention has the following advantages compared with the prior art:

[0021] The reactor provided by the present invention is used in conjunction with corresponding equipment to simultaneously realize simulation research on temperature, time, static rock pressure, fluid pressure, confining pressure, fluid medium, formation pore space and true biaxial rock mechanics under deep and ultra-deep conditions in oil and gas basins, thereby solving the problems of mismatch between simulation conditions and actual geological conditions, low overall accuracy of the control system, poor repeatability, and weak high-frequency continuous online observation capabilities in traditional methods, thereby obtaining accurate model evaluation parameters for the interaction between deep formation fluid and rock, and providing more scientific, accurate, safe and efficient technical solutions for the field of petroleum experimental equipment and technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0023] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0024] Figure 1 This is a cross-sectional view of a fluid-rock interaction reactor under true biaxial stress according to an embodiment of the present invention;

[0025] Figure 2 This is an exploded view of a reactor for fluid-rock interaction under true biaxial stress according to an embodiment of the present invention;

[0026] Figure 3 This is a structural schematic diagram of the arrangement of the flow field adjustment mechanism, the sealing assembly, and the pressing assembly according to an embodiment of the present invention;

[0027] Figure 4 An exploded view of the arrangement of the flow field adjustment mechanism, the sealing assembly, and the pressing assembly according to an embodiment of the present invention;

[0028] Figure 5 Schematic diagram of the structure of the reaction shell according to an embodiment of the present invention.

[0029] Description of Reference Numerals

[0030] 1. Reaction shell; 11. Socket; 2. Rock sample; 3. Flow field adjustment mechanism; 31. Pressure rod; 311. Guide hole; 32. Diversion assembly; 321. Sintered plate; 322. Sealing block; 33. Straightening ring; 331. First opening; 4. Sealing assembly; 41. Sealing ring; 411. First annular protrusion; 42. First copper sealing ring; 43. Graphite sealing ring; 44. Second copper sealing ring; 5. Clamping assembly; 51. Pressure cap; 511. Second annular protrusion; 52. Limiting ring; 521. Second opening. DETAILED DESCRIPTION

[0031] In order to more clearly understand the above-mentioned objects, features and advantages of the present invention, the scheme of the present invention will be further described below. It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other.

[0032] The following description sets forth many specific details to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein; it is obvious that the implementation methods in the specification are only part of the implementation methods of the present invention, not all of the implementation methods.

[0033] Combine Figures 1 to 4As shown, the fluid-rock interaction reactor under true biaxial stress provided by the embodiment of the present invention includes a reaction shell 1 and four flow field adjustment mechanisms 3.

[0034] The reaction housing 1 is provided with two intersecting through-holes, preferably perpendicular to each other. The intersection of the two through-holes forms a cavity for receiving the rock sample 2. This cavity divides the two through-holes into four insertion holes 11. With this design, the rock sample 2 can be inserted into the cavity along the insertion holes 11 according to a predetermined direction, increasing operational convenience.

[0035] Rock sample 2 is cut into cube blocks from dense sandstone cores or outcrop blocks based on the rock's internal structure, laminae, bedding fractures, or physical properties. Square blocks are preferably 25 x 25 mm. Rock samples 2 of highly brittle rock types, such as shale, mudstone, carbonaceous mudstone, and coal, should be cut into smooth cubes using a liquid nitrogen cryo-cutter or molybdenum wire cutter. The non-static pressure side of the cube rock sample 2 is marked with a manual chisel or bottle engraving machine. The cube rock sample 2 is then pushed into the central cavity of the reaction shell 1 in a fixed orientation, ensuring a contact fit between the rock sample 2 and the reaction shell 1.

[0036] A flow field regulating mechanism 3 is inserted into each socket 11. The flow field regulating mechanism 3 includes a pressure rod 31 and a diverter assembly 32 provided at the end of the pressure rod 31. A plurality of diverter holes are formed in the diverter assembly 32. A guide hole 311 is provided inside the pressure rod 31 to communicate with the plurality of diverter holes. The end of the guide hole 311 facing away from the diverter assembly 32 is used to communicate with the liquid supply pipe. The diverter assembly 32 is used to support the side of the rock sample 2, and the side of the diverter assembly 32 not in contact with the rock sample 2 is closed. A sealing assembly 4 is provided between the pressure rod 31 and the inner wall of the socket 11. The diverter assembly 32 is in contact with the rock sample 2, and the pressure rod 31 and the sealing assembly 4 are in interference fit. Under this design, the target liquid provided by the liquid supply pipe can flow to the diverter hole through the guide hole 311, and thereby act on the side of the rock sample 2.

[0037] In some embodiments, a flow guide hole 311 is provided at the axis of the pressure rod 31, through which high-pressure fluid flows. A threaded opening is provided at the end of the pressure rod 31 facing away from the rock sample 2, which is threadedly connected to a liquid supply pipe to increase the convenience of disassembly and assembly. A high-pressure pump is connected to the end of the liquid supply pipe facing away from the threaded opening, so that the high-pressure pump can supply a target liquid at a certain pressure to the liquid supply pipe. The pressure rod 31 can move along the axial direction of the pressure rod 31 within the insertion hole 11, and the end of the pressure rod 31 with the threaded opening can directly withstand the pressure of an external mechanical device, so that the pressure rod 31 can move toward the rock sample 2 under the action of the external mechanical device pressure, so that the external mechanical device pressure is indirectly applied to the surface of the rock sample 2 as static rock pressure through the pressure rod 31.

[0038] The reactor provided by the present invention is used in conjunction with corresponding equipment to simultaneously realize simulation research on temperature, time, static rock pressure, fluid pressure, confining pressure, fluid medium, formation pore space and true biaxial rock mechanics under deep and ultra-deep conditions in oil and gas basins, thereby solving the problems of mismatch between simulation conditions and actual geological conditions, low overall accuracy of the control system, poor repeatability, and weak high-frequency continuous online observation capabilities in traditional methods, thereby obtaining accurate model evaluation parameters for the interaction between deep formation fluid and rock, and providing more scientific, accurate, safe and efficient technical solutions for the field of petroleum experimental equipment and technology.

[0039] The fluid-rock interaction reactor under true biaxial stress disclosed in the present invention can be used for shale oil and gas, tight oil and gas, coal measures, and heavy oil, etc. The research content involves hydrocarbon generation and expulsion simulation, diagenesis, pore evolution, fluid phase state, reservoir transformation, core displacement, etc. The scope of application covers reservoir heterogeneity, stress anisotropy, and enhanced recovery (water flooding, chemical flooding, microbial flooding). It can also be simply used as a core holder to carry out porosity and permeability testing, as well as laminar-level fluid fine-grained fingerprint identification and comparison, and accurate and efficient fluid tracing and tracing.

[0040] In some embodiments, continue with reference to Figures 1 to 4 The diversion assembly 32 includes a conical sintered plate 321, and a plurality of diversion holes are arranged inside the sintered plate 321. The end face of the sintered plate 321 is supported on the side of the rock sample 2. The diversion assembly 32 also includes a sealing block 322 surrounding the outer periphery of the sintered plate 321, and the pressure rod 31 abuts against the end face of the sealing block 322. Among them, a conical hole matching the structure of the conical sintered plate 321 is formed inside the sealing block 322, so that the sealing block 322 can be sleeved on the outer periphery of the sintered plate 321, and the inner wall of the conical hole of the sealing block 322 can be included in the outer periphery of the conical surface of the sintered plate 321, thereby ensuring the sealing effect. Among them, the sintered plates 321 with different porosities can be replaced according to different test requirements.

[0041] Specifically, the sintered plate 321 is a conical high-precision micron-level sintered plate 321, which is a high-strength porous medium. The sintered plate 321 can withstand and transmit the mechanical pressure of the pressure rod 31 to the surface of the rock sample 2. At the same time, the porous media of different porosities are used to approximate the flow field of the high-pressure fluid to a plug flow acting on the surface of the rock sample 2. The conical high-precision micron-level sintered plate 321 and the sealing block 322 are in conical contact and fit. After being subjected to stress within a reasonable tolerance range of the end face, there is a certain expansion and contraction gap. The sealing block 322 is in gap fit with the socket 11 of the reaction shell 1. The sealing block 322 surrounds the outer periphery of the conical high-precision micron-level sintered plate 321 to form a water blocking structure, so that the liquid entering the diversion hole can only flow toward the direction of the rock sample 2, and then act on the side of the rock sample 2.

[0042] A stabilizing ring 33 is provided at the end of the pressure rod 31 facing away from the diverter assembly 32. This ring is coaxially arranged with the pressure rod 31 and has a sidewall provided with a first opening 331 for a fluid supply line. The end of the stabilizing ring 33 facing away from the pressure rod 31 is connected to a first hydraulic assembly, which provides a certain pressure to the stabilizing ring 33. This pressure is then transmitted to the side of the rock sample 2 through the pressure rod 31 and the diverter assembly 32. The stabilizing ring 33 is cap-shaped, with a through-groove defined in the cylindrical sidewall for routing the fluid line from the high-pressure pump out of the reactor.

[0043] The socket 11 has a stepped surface, with one end of the sealing assembly 4 abutting against it. A clamping assembly 5 is provided at the other end of the sealing assembly 4. The end of the clamping assembly 5, facing away from the stepped surface of the socket 11, is connected to a second hydraulic assembly. The second hydraulic assembly transmits pressure to the sealing assembly 4 via the clamping assembly 5, thereby compressing the sealing assembly 4 between the clamping assembly 5 and the stepped surface of the socket 11, ensuring a secure seal.

[0044] In some embodiments, combined Figures 1 to 4 As shown, the sealing assembly 4 includes a sealing ring 41, a first copper sealing pressure ring 42, a graphite sealing pressure ring 43, and a second copper sealing pressure ring 44, which are sequentially arranged along the step surface. The sealing assembly 4 with this design can ensure the sealing effect between the pressure rod 31 and the socket 11.

[0045] As a feasible implementation, the sealing ring 41 is made of 316L stainless steel.

[0046] like Figure 3As shown, a first annular protrusion 411 is provided on the side of the sealing ring 41 facing the first copper sealing pressure ring 42, and a first annular groove is provided on the first copper sealing pressure ring 42 to match the first annular protrusion 411. This design ensures a tight fit between the sealing ring 41 and the first copper sealing pressure ring 42, while also ensuring that the sealing ring 41 and the first copper sealing pressure ring 42 are coaxially arranged, thereby ensuring a good sealing effect.

[0047] Specifically, the sealing ring 41 forms an interference fit with the socket 11, and the first copper sealing pressure ring 42 also forms an interference fit with the inner wall of the socket 11. The side of the sealing ring 41 that contacts the stepped surface of the socket 11 is flat, ensuring stable contact between the sealing ring 41 and the stepped surface. The side of the sealing ring 41 that faces the first copper sealing pressure ring 42 is provided with an annular first annular protrusion 411. The cross-section of the first annular protrusion 411 is inverted V-shaped, and the first annular groove is V-shaped to ensure accurate positioning and convenient installation.

[0048] During use, the reactor can be placed in a temperature control system with a set temperature. The temperature control system can accurately simulate the temperature of deep formations. This temperature control system is conventional technology, and therefore its structure and working principle are not described in detail here. As the temperature of the reactor rises and the pressure acting on the compression assembly 5 increases, the first copper sealing ring 42 and the sealing ring 41 undergo plastic deformation between the first annular protrusion 411 and the V-shaped opening, filling the irregular roughness of the contact surface of the inner and outer walls of the ring to form a first seal, compensating for the insufficient sealing effect of the interference fit between the materials on high-temperature and high-pressure fluids.

[0049] The port at the end where the first copper sealing ring 42 contacts the graphite sealing ring 43 is flat, and the port within the end where the graphite sealing ring 43 contacts the first copper sealing ring 42 is also flat, ensuring planar contact between the first copper sealing ring 42 and the graphite sealing ring 43. There are two graphite sealing rings 43, both of which are made of nickel-wire-reinforced expanded graphite packing rings. Both have square cross-sections and exhibit good flexibility, a high coefficient of resilience, and excellent thermal stability, self-lubrication, and chemical stability. The graphite sealing rings 43 also form an interference fit with the inner wall of the socket 11.

[0050] The compression assembly 5 includes a pressure cap 51 that is sleeved around the outer periphery of the pressure rod 31. A portion of the pressure cap 51 extends into the socket 11 and abuts against the side of the second copper sealing ring 44, while the other portion of the pressure cap 51 is supported at the end of the socket 11. This design ensures that the pressure cap 51 can compress the sealing assembly 4 under the action of an external force. At the same time, the portion of the pressure cap 51 supported at the end of the socket 11 can limit the travel of the pressure cap 51, thereby limiting the amount of pressure exerted by the pressure cap 51 on the sealing assembly 4 and preventing damage to the sealing assembly 4 due to excessive pressure.

[0051] Among them, the pressure cap 51 is made of 316L stainless steel. The function of the pressure cap 51 is mainly to provide axial sealing pressure for the sealing component 4. Its upper end face bears the pressure of another independent external mechanical equipment, and transmits the mechanical pressure as sealing pressure to the sealing component 4 through the following limiting pressure ring 52 and the pressure cap 51. There is a clearance fit between the pressure cap 51 and the pressure rod 31, so that the pressure rod 31 can move relative to the pressure cap 51 along the axial direction of the pressure rod 31.

[0052] Further optimized, a second annular protrusion 511 is provided on the side of the pressure cap 51 facing the second copper sealing ring 44, and a second annular groove is provided on the second copper sealing ring 44 to match the second annular protrusion 511. This design allows the pressure cap 51 and the second copper sealing ring 44 to fit tightly together and ensures that the pressure cap 51 and the second copper sealing ring 44 are coaxially arranged, thereby ensuring a good sealing effect.

[0053] Specifically, the side of the second copper sealing ring 44 that contacts the graphite sealing ring 43 is a plane, so that the second copper sealing ring 44 is in plane contact with the graphite sealing ring 43. The side of the pressure cap 51 facing the second copper sealing ring 44 is provided with a second annular protrusion 511. The cross-section of the second annular protrusion 511 is V-shaped, and the second annular groove is in an inverted V shape, so as to ensure the accuracy of positioning and the convenience of installation.

[0054] Similar to the working principle of the first copper sealing pressure ring 42 and the sealing ring 41 mentioned above, as the temperature of the reactor increases and the pressure acting on the pressure cap 51 increases, plastic deformation occurs between the second annular protrusion 511 and the second annular groove, filling the irregular roughness of the contact surface of the inner and outer walls of the ring to form a second seal, further compensating for the insufficient sealing effect of the interference fit between the materials on high-temperature and high-pressure fluids.

[0055] The sealing assembly 4 under this design achieves the effect of rough surface sealing. The graphite sealing pressure ring 43 has good toughness and heat insulation performance, and is used to form a local temperature gradient on the interference fit surface, promoting irregular plastic creep of the copper sealing pressure ring and enhancing the sealing effect.

[0056] Combine Figures 1 to 4 As shown, the compression assembly 5 also includes a limiting pressure ring 52 that is sleeved on the outer circumference of the compression rod 31. The limiting pressure ring 52 abuts against the side of the pressure cap 51 that faces away from the second copper sealing pressure ring 44. The limiting pressure ring 52 is provided with a second opening 521 for the liquid supply pipeline to pass through, so that the cross-section of the limiting pressure ring 52 is C-shaped. During use, the liquid supply pipeline can be led out through the first opening 331 and the second opening 521 in sequence. The limiting pressure ring 52 is used to contact external mechanical equipment to bear the pressure transmitted by the external mechanical equipment and transmit the pressure to the sealing assembly 4 through the pressure cap 51.

[0057] Among them, a large gap is left between the limiting pressure ring 52 and the pressure rod 31, and the side wall cylindrical surfaces of the limiting pressure ring 52 and the straightening pressure ring 33 are both provided with through grooves (the first opening 331 and the second opening 521). While leading the fluid pipeline of the high-pressure pump out of the reactor, the double-piston rod double-acting hydraulic press (the above-mentioned external mechanical equipment) is prevented from axial misalignment. The straightening pressure ring 33 is combined with the limiting pressure ring 52 to realize the control of the shape and position deviation of the entire reactor and the four pressure rods 31.

[0058] The connections between the various components of the reactor under this design adopt interference sealing technology with a completely threadless design, which realizes the coupled field effect of temperature, dynamic mechanical pressure and fluid pressure, and realizes the calculation of accurate model evaluation parameters for simulating the interaction between deep formation fluid and rock.

[0059] like Figure 5 As shown, the reaction housing 1 is a cross structure, and the two through holes extend along the two vertically arranged symmetry axes of the reaction housing 1. The reaction housing 1 with this design can meet the requirements of opening two through holes while occupying less space, increasing the convenience of use.

[0060] Specifically, the reaction shell 1 is made of nickel-based high-temperature alloy steel that is resistant to high temperature, high pressure, and acid and alkali corrosion. The kettle body is in a vertically orthogonal cross shape, so that it has true biaxial stress in the vertical direction, and can simultaneously simulate the deep underground temperature, time, static rock pressure, fluid pressure, confining pressure, fluid medium, formation pore space, and the interaction between fluid and rock under true biaxial rock mechanics conditions. The reaction shell 1 adopts a non-threaded design, and a cylindrical straight hole is opened in four directions to form a socket 11. A four-way through square straight hole is opened on the bottom end face of the socket 11 to form a cavity. The cube-shaped rock sample 2 is located in the square straight hole, and the step surface of the square straight hole is in contact with the sealing ring 41. Further optimized, the corner position of the reaction shell 1 is smoothly transitioned to increase the structural strength of the reaction shell 1.

[0061] The reactor provided by the present invention is used in conjunction with external mechanical equipment, wherein the external mechanical equipment includes a four-way hydraulic axial pressure mechanism, that is, there can be four hydraulic axial pressure mechanisms, which are mainly provided by a double-acting hydraulic press with two piston rods in the same direction to control the four directions, totaling eight external mechanical pressures. The double-acting double piston rods in the same direction can independently control the pressure on the shaft and sleeve. The shaft acts on the end face of the centralizing pressure ring 33, and the sleeve acts on the end face of the limiting pressure ring 52, thereby achieving the synergistic effect of static rock pressure and sealing pressure. The static rock pressure is the pressure acting on the rock sample 2, and the sealing pressure is the pressure acting on the sealing assembly 4.

[0062] Specifically, each flow field regulating mechanism 3 corresponds to a hydraulic axial pressure mechanism, which provides static rock pressure and sealing pressure to the straightening pressure ring 33 and the limiting pressure ring 52, respectively. The static rock pressure is (0-200 MPa) and the sealing pressure is (0-120 MPa). The static rock pressure and sealing pressure are independently controlled. During the experiment, the numerical changes of the static rock pressure and sealing pressure need to be continuously and frequently collected and stored in the database. Among them, the same-direction double-piston rod double-acting hydraulic press is a conventional technology in this field. Therefore, its structure and working principle are not described in detail here.

[0063] The external mechanical equipment also includes a four-way high-pressure fluid mechanism, primarily composed of a dual-cylinder, dual-acting high-pressure pump and a high-pressure fluid intermediate unit. The fluid required for the reaction is placed into the intermediate unit. Specifically, the intermediate unit communicates with the four flow field adjustment mechanisms 3's flow guide holes 311, enabling it to independently supply fluid at a specific pressure to each of the four flow field adjustment mechanisms 3's flow guide holes 311. The dual-cylinder, dual-acting high-pressure pump can continuously and stably provide high-pressure fluid up to 120 MPa. According to the needs of the research, the high-pressure fluid can be set to be injected from a fixed direction and then detected and the products are collected in the other three directions. Specifically, it flows from the guide tube of one of the flow field regulating mechanisms 3 to the diversion component 32, acts on the side of the rock sample, and flows to the inside of the rock sample, and then flows out through the diversion components 32 and guide tubes of the other three flow field regulating mechanisms 3. It can also be injected from two adjacent positions with different pressures, and the input of the product is detected from the other two directions. Specifically, it flows from the guide tubes of two of the flow field regulating mechanisms 3 to the diversion component 32, acts on the side of the rock sample, and flows to the inside of the rock sample, and then flows out through the diversion components 32 and guide tubes of the other two flow field regulating mechanisms 3. Of course, it can also be used as a displacement experimental device, injecting fluids of different properties from different directions, and judging the heterogeneity inside the sample by detecting the products.

[0064] In addition, during the experiment, the accurate values of the inlet and outlet fluid pressures need to be continuously collected at high frequency and stored in the database. The gas and liquid products generated during the experiment need to be monitored online at high frequency for their component content after passing through an effective separation device, and data mining is carried out using big data artificial intelligence algorithms. Real-time dynamic fingerprint recognition can directly reflect the changing characteristics of the products.

[0065] External mechanical equipment also includes a reactor heating device, which is used to heat the reactor. The reactor heating device mainly consists of a heating furnace (20-650°C), temperature-control thermocouples, temperature-measuring thermocouples, and a temperature control digital display. The entire reactor is placed in the heating furnace and heated to the target temperature according to the set temperature control program.

[0066] The reactor provided in this application is used to connect with a four-way hydraulic axial pressure mechanism and a four-way high-pressure fluid mechanism, and can be placed in a reactor heating device, and then can be used in conjunction with the four-way hydraulic axial pressure mechanism and the four-way high-pressure fluid mechanism and the reactor heating device to simulate the fluid-rock interaction process under the conditions of deep and ultra-deep layers in oil and gas basins with temperatures of 20 to 650°C, static rock pressure of 0 to 200 MPa, and fluid pressure of 0 to 120 MPa. Its main feature is the complex fluid-solid coupling field reaction under true biaxial stress, which meets the needs of studying the heterogeneity of directional rock samples 2, and requires that the corresponding product detection device must have a lower detection line and a higher resolution.

[0067] Before the experiment, the reactor provided by the present invention needs to be inspected in detail for the integrity of the reactor accessories and their processing technology, and unqualified accessories need to be replaced in time. For reactors that are used repeatedly for a long time, the shape and position tolerances of the reaction shell 1 and each component of the reactor need to be verified before the experiment to prevent micro cracks and sand holes caused by metal fatigue. According to the needs of the research purpose, a cubic oriented rock sample 2 is prepared and pushed flat into the cavity of the reaction shell 1 of the reactor according to the direction required by the experiment. Among them, the directional mark should be marked after repeated experiments to avoid mixing. The reaction shell 1 is placed flat, and the flow field adjustment mechanism 3 in four directions is installed in turn. After the conical high-precision micron-level sintered plate 321 is buckled with the sealing block 322, it is pushed into the middle cavity of the reaction shell 1 in relative directions, and in contact with the rock sample 2. The four-way sealing assembly 4 needs to be installed outside the reaction shell 1. The sealing ring 41, the first copper sealing pressure ring 42, the two graphite sealing pressure rings 43 and the second copper sealing pressure ring 44 are installed on the pressure rod 31 in the correct assembly order (installed from the distal end to the proximal end), and are pressed into the socket 11 of the reactor together with the pressure rod 31.

[0068] At the top threaded opening of the pressure rod 31, connect the conical threaded joint on the liquid supply pipe and rotate the tightening screw. Install the pressure cap 51, the limiting pressure ring 52 and the straightening pressure ring 33 respectively, and pass the liquid supply pipe through the first opening 331 and the second opening 521. The reactor containing the rock sample 2 is assembled. Install the horizontal reactor on the same-direction double-piston rod double-acting hydraulic station. First adjust the static rock pressure on the hydraulic press to ensure its axis is aligned, and then adjust the sealing pressure on the sleeve. Ensure its axis is aligned through the straightener. Connect the temperature-controlled thermocouple to the reactor, close the high-temperature furnace door, and independently adjust the size of the 8 pressure values in the four directions. Write the program temperature rise record into the host computer, prepare the high-pressure fluid system, and complete the preparations before the experiment.

[0069] The experimental process of the fluid-rock interaction reactor under true biaxial stress provided by the present invention is as follows:

[0070] In step S1, a cube rock sample 2 is pushed into the middle cavity of the reaction shell 1 in a fixed direction, and the gap and contact flatness between the rock sample 2 and the surface of the reaction shell 1 are checked. If the rock sample 2 is damaged inside or the surface is uneven, it needs to be re-prepared or the surface polished.

[0071] In step S2, all accessories of the reactor must be installed one by one in strict accordance with their respective assembly relationships and in the specified order. If any accessories are found to be incorrectly installed or missing during installation, they must be completely removed using proprietary tools, and the sealing kit must be replaced before reinstallation. Before transferring the reactor to the hydraulic press, the directional markings on the reactor surface must be strictly matched to the directional markings on the hydraulic press. Reverse or reverse installation is strictly prohibited. Before the experiment begins, the reactor must be completely evacuated through the liquid supply pipeline. The signal acquisition and transmission of each pressure transmitter, temperature sensor, and hydraulic workstation must be checked for normal response. The pneumatic control system and circuit system must also be checked for component response speed.

[0072] Step S3: Applying rock static pressure

[0073] Specifically, the hydraulic workstation is used to adjust the four same-direction double-piston-rod double-acting hydraulic cylinders close to the reactor, and at the same time, the shaft cylinders in the opposite directions are extended to act on the top of the positive pressure ring 33 respectively. After adjusting the position of the control reactor, the shaft cylinders in another pair of directions are extended, and the displayed value of the static rock pressure is repeatedly adjusted in pairs (temporarily set to about 60% of the target static rock pressure value, and increased to the target static rock pressure after reaching the target temperature) to ensure that the final reactor body is centered.

[0074] Step S4, applying the sealing pressure

[0075] Specifically, the hydraulic workstation is used again to adjust the sleeve cylinders of the four same-direction double-piston-rod double-acting hydraulic presses close to the limit pressure ring 52. There is a large gap between the limit pressure ring 52 and the pressure rod 31. The position of the limit pressure ring 52 is appropriately adjusted, and the sealing pressure is repeatedly adjusted in pairs until the target value required for the experiment (at least 40 MPa) is reached.

[0076] Step S5, applying the reaction temperature

[0077] Specifically, check the temperature control system and heat dissipation system of the high-temperature furnace, connect the temperature control thermocouple and the temperature measuring thermocouple to the designated position of the reactor, and close the high-temperature furnace door.

[0078] Step S6: Apply fluid pressure

[0079] Start the high-pressure pump. The dual-cylinder, double-acting high-pressure pump needs to be reset in advance and set to a pressure mode, either constant pressure (0-120 MPa) or constant flow (0.2 ml / min). The high-pressure pump pushes high-pressure water into a high-pressure intermediate container (450 ml). The piston in the middle of the high-pressure container separates the fluid required for the reaction, typically deionized water, organic acid, oilfield water, or other specially formulated solutions. Secure the intermediate container with a sealing cap to expel excess air.

[0080] After setting the fluid pressure reference value Pref, maximum value Pmax, minimum value Pmin, and automatic pressure compensation threshold in the host computer control program, the high-pressure fluid passes through the high-pressure container, pressure transmitter, fluid supply pipeline, pressure rod 31, and blocking block 322. After undergoing flow field modification by the conical, high-precision, micron-scale sintered plate 321, it reacts with the cube rock sample 2. The fluid is then discharged from another pressure rod 31 and flows through the autoclave's fluid supply pipeline into the reaction product collector. The fluid control system uses circuit-controlled solenoid valve reversal to change the air path direction, thereby opening and closing the valve needle and controlling the flow of the fluid.

[0081] Step S7, experiment in progress

[0082] The experimental process required the coordinated control of multiple systems, including the hydraulic control system, temperature control system, electrical circuit control system, high-pressure fluid control system, and data signal acquisition system. The temperature control system, following the pre-experimental heating program, servo-controlled and recorded the reactor temperature in real time. The hydraulic control system continuously output four sealing pressures and dynamically adjusted the output of four static rock pressures. The high-pressure fluid system coordinated with the electrical circuit control system to control the fluid pressure inside the reactor, and recorded the pressure in real time through pressure transmitters at the inlet and outlet. The data acquisition system, installed on the upper industrial computer, collected data from each system in real time.

[0083] Step S8, collection of experimental products

[0084] The high-pressure fluid passing through the reactor is the experimental product. The high-temperature gas-liquid mixed fluid is output from the pressure rod 31 to the liquid supply pipeline, and is measured by the pressure transmitter after preliminary cooling. The gas-liquid products then enter the gas-liquid separator. The gas portion enters the volume quantification, gas collection, and online analysis system separately, while the liquid portion remains independently in the gas-liquid separator and is collected and analyzed at regular intervals. The solid rock residue taken out after the experiment is a solid product.

[0085] Step S9, experimental data collection

[0086] During the simulation experiment, data acquisition uses high-frequency digital signal transmission, including four sealing pressures, four static rock pressures, reactor temperature, inlet fluid pressure, outlet fluid pressure, intermediate container fluid quantity, gas product volume, liquid product volume and subsequent gas and liquid product component fingerprint identification data. All data are submitted to the host computer database and dynamically visualized.

[0087] Step S10, unloading the sample

[0088] After the experiment is completed, stop the high-pressure pump, open the reactor outlet, and discharge all the pressure in the reactor, which is then combined and recorded in the product collection system. After the fluid pressure drops to 0 MPa, turn off the heating of the high-temperature furnace and start the heat dissipation. After the reactor approaches room temperature, use the hydraulic workstation to unload the sealing pressure and static rock pressure in sequence, and remove the reactor. Manually remove the limiting pressure ring 52 and the straightening pressure ring 33, and then use a uniaxial press to press the pressure rod 31 that passes through one side. The rock sample 2 and the pressure rod 31 in the opposite direction can be pushed out. Similarly, push out the pressure rod 31 in the other direction, use a special rotary shaft remover to remove the sealing assembly 4 and the pressure cap 51, and complete the disassembly of the reactor.

[0089] The reactor for fluid-rock interaction under true biaxial stress provided by the present invention can accurately simulate the temperature, time, static rock pressure, fluid pressure, confining pressure, fluid medium and formation pore space of deep formations, as well as the fluid-rock interaction under true biaxial rock mechanics, thereby obtaining accurate model evaluation parameters for the interaction between fluid and rock in deep formations, and also providing a more scientific, accurate, comprehensive and efficient technical solution for the field of petroleum experimental equipment and technology. The experimental method using the reactor of the present invention is simple to operate and the experimental conditions are controllable. It can comprehensively collect various experimental parameters, providing a rich and accurate data source for subsequent data analysis and model establishment. At the same time, the sealing component 4 and the clamping component 5 adopted by the present invention ensure the safety of the experimental process and improve the stability and reliability of the experiment. It is suitable for the field of petroleum experimental equipment and technology, helps to improve the scientificity, accuracy and efficiency of geological exploration and development, and provides more powerful model evaluation parameters for deep oil and gas resource research.

[0090] The flow field regulating mechanism 3, sealing component 4 or pressing component 5 etc. illustrated in the above embodiments can be realized by other materials, or by a combination of products with certain functions. For the convenience of description, the above devices and mechanisms are divided into various auxiliary devices according to their functions or described as mechanisms with several uses. Of course, when implementing the patent of this invention, the functions of each device or the design scheme of a mechanism can be implemented in the same combination of one or more materials or shapes, or the mechanism that realizes the same function can be realized by a combination of multiple sub-mechanisms, etc. The device embodiments described above are merely schematic. For example, the division of the sealing component 4 is only a logical functional division, and the actual implementation may have another division method.

[0091] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article, or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or device. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of other identical elements in the process, method, article, or device comprising the element.

[0092] The foregoing description is intended only to provide specific embodiments of the present invention, which will enable those skilled in the art to understand and implement the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not intended to be limited to the embodiments described herein, but is to be construed in the widest possible manner consistent with the principles and novel features disclosed herein.

Claims

1. A fluid-rock interaction reactor under true biaxial stress, characterized in that: include: The reaction shell (1) is provided with two cross-arranged through-holes, the intersection of the two through-holes forms a cavity for accommodating the rock sample (2), and the cavity divides the two through-holes into four insertion holes (11); Four flow field regulating mechanisms (3), one of the flow field regulating mechanisms (3) is inserted into each of the jacks (11), the flow field regulating mechanisms (3) include a pressure rod (31) and a diversion assembly (32) arranged at the end of the pressure rod (31), a plurality of diversion holes are formed in the diversion assembly (32), a guide hole (311) connected to the plurality of diversion holes is provided inside the pressure rod (31), an end of the guide hole (311) facing away from the diversion assembly (32) is used to communicate with a liquid supply pipeline, the diversion assembly (32) is used to support the side of the rock sample (2), and the side of the diversion assembly (32) not in contact with the rock sample (2) is closed, and a sealing assembly (4) is provided between the pressure rod (31) and the inner wall of the jack (11).

2. The fluid-rock interaction reactor under true biaxial stress according to claim 1, characterized in that: The diversion assembly (32) includes a conical sintered plate (321), a plurality of diversion holes are arranged inside the sintered plate (321), and the end face of the sintered plate (321) is supported on the side of the rock sample (2). The diversion assembly (32) also includes a sealing block (322) surrounding the outer periphery of the sintered plate (321), and the pressure rod (31) is in contact with the end face of the sealing block (322).

3. The fluid-rock interaction reactor under true biaxial stress according to claim 1, characterized in that: A stabilizing ring (33) is provided at one end of the pressure rod (31) facing away from the diversion assembly (32). The stabilizing ring (33) is coaxially arranged with the pressure rod (31). The side wall of the stabilizing ring (33) is provided with a first opening (331) for the liquid supply pipeline to pass through.

4. The fluid-rock interaction reactor under true biaxial stress according to claim 1, characterized in that: The insertion hole (11) has a stepped surface, one end of the sealing component (4) abuts against the stepped surface, and the other end of the sealing component (4) is provided with a pressing component (5).

5. The fluid-rock interaction reactor under true biaxial stress according to claim 4, characterized in that: The sealing assembly (4) comprises a sealing ring (41), a first copper sealing pressure ring (42), a graphite sealing pressure ring (43), and a second copper sealing pressure ring (44) which are sequentially arranged along a surface away from the step.

6. The fluid-rock interaction reactor under true biaxial stress according to claim 5, characterized in that: A first annular protrusion (411) is provided on one side of the sealing ring (41) facing the first copper sealing pressure ring (42), and a first annular groove matching the first annular protrusion (411) is provided on the first copper sealing pressure ring (42).

7. The fluid-rock interaction reactor under true biaxial stress according to claim 5, characterized in that: The pressing assembly (5) includes a pressing cap (51) sleeved on the outer periphery of the pressing rod (31), a portion of the pressing cap (51) extends into the jack (11) and abuts against the side of the second copper sealing ring (44), and another portion of the pressing cap (51) is supported at the end of the jack (11).

8. The fluid-rock interaction reactor under true biaxial stress according to claim 7, characterized in that: The clamping assembly (5) further comprises a limiting pressure ring (52) sleeved on the outer periphery of the pressure rod (31), the limiting pressure ring (52) abutting against a side of the pressure cap (51) facing away from the second copper sealing pressure ring (44), and a second opening (521) for the liquid supply pipe to pass through is provided on the limiting pressure ring (52).

9. The fluid-rock interaction reactor under true biaxial stress according to claim 7, characterized in that: A second annular protrusion (511) is provided on one side of the pressure cap (51) facing the second copper sealing pressure ring (44), and a second annular groove matching the second annular protrusion (511) is provided on the second copper sealing pressure ring (44).

10. The fluid-rock interaction reactor under true biaxial stress according to claim 1, characterized in that: The reaction housing (1) is in a cross structure, and the two through holes extend along the directions of two vertically arranged symmetry axes of the reaction housing (1).

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