Preparation method of composite film state oil and gas reservoir visual model and application of obtained model

Abstract

The invention relates to a preparation method of a composite film state oil and gas reservoir visual model and application of the obtained model, in particular to the technical field of petroleum development and research, and the preparation method comprises the following steps: obtaining model parameters having a similar relationship with actual oil and gas reservoir parameters according to a similarity criterion; constructing a visual physical model of the complex membrane state strong heterogeneity oil and gas reservoir according to the model parameters having the similar relationship with the actual oil and gas reservoir parameters; wherein the similarity conditions of the model parameters obtained according to the similarity criterion comprise model geometric similarity, model boundary condition similarity, reservoir feature similarity, injection-production parameter similarity, fluid physical property similarity and oil-gas miscible state similarity. According to the method provided by the invention, the geologic structure, the fluid physical property and the mining condition of the complex membrane state strong heterogeneity oil and gas reservoir are simulated by virtue of a similarity principle, the obtained model can be used for a displacement experiment, and an effective model preparation method is provided for experimental research on development of the complex membrane state strong heterogeneity oil and gas reservoir.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of oil development research, in particular to a preparation method of a visual model of a complex membrane oil and gas reservoir and use of the obtained model, and more particularly to a preparation method of a visual physical model of a complex membrane strong heterogeneous oil and gas reservoir and use of the obtained model. BACKGROUND

[0002] At present, due to the influence of sedimentary environment, diagenesis and tectonic action, various components in the internal reservoir of the oil and gas reservoir change unevenly in space. This uneven change is specifically manifested in the inconsistency of internal component characteristics such as lithology, physical property, oil content and micro-pore structure of the oil and gas reservoir and spatial distribution of the oil and gas reservoir. As an important factor affecting the flow and distribution of oil, gas and water in the formation and the recovery efficiency, the research on the heterogeneity of the oil and gas reservoir has always been the focus of the field of oil and gas.

[0003] The strong heterogeneity factors (including fractures, solution cavities, faults, dip angles, etc.) of the oil and gas reservoir have a great influence on the flow of fluids in the formation. If the percolation mechanism of oil and gas when flowing through various strong heterogeneity factors is not clear during the exploitation of such oil and gas reservoirs, it will seriously affect the exploitation effect of the oil and gas reservoir. Therefore, it is particularly necessary to study the strong heterogeneity factors of the oil and gas reservoir.

[0004] CN116559938A discloses an oil and gas reservoir fracture model establishment method and electronic equipment. The oil and gas reservoir fracture model establishment method comprises: establishing a structure-stratigraphic framework model and an oil and gas reservoir fracture geological concept model respectively; extracting a plurality of seismic fracture detection attribute bodies, and optimizing the most similar seismic fracture detection attribute body; calculating an ant body fracture tracking attribute and obtaining a fracture piece set of an oil and gas reservoir target area, and obtaining a target oil and gas reservoir fracture envelope attribute body; dividing the fracture system envelope into a joint fracture zone and a dispersed fracture zone; marking the dispersed data of a fracture development facies zone, and establishing a fracture development facies zone dispersivity geological model; and establishing a large-scale fracture model, a medium-scale fracture model and a small-scale fracture model.

[0005] However, in the research on the heterogeneous oil and gas reservoir in the prior art, there is almost no experimental method that can directly reflect the dynamic changes of the interface between the displacement phase and the displaced phase during the exploitation process. The previous research method cannot directly observe the sweep characteristics of the displacement phase, which leads to the inability to reasonably analyze the dynamic changes of the interface between the displacement phase and the displaced phase and the sweep characteristics of the displacement phase, so that the production amount of the oil and gas reservoir cannot be effectively analyzed when the production amount is unreasonable. SUMMARY

[0006] In view of the problems in the prior art, the purpose of the present application is to provide a preparation method of a visual model of a complex-film oil and gas reservoir capable of effectively simulating strong heterogeneity features such as cracks and caves, and the use of the obtained model, for solving the defects that the existing research methods cannot directly observe the sweep characteristics of the displacement phase, resulting in the inability to reasonably analyze the dynamic changes of the displacement phase and the displaced phase interface and the sweep characteristics of the displacement phase, and making it impossible to effectively analyze the unreasonable production when the oil and gas reservoir is produced.

[0007] To achieve this purpose, the present application adopts the following technical solutions:

[0008] In a first aspect, the present application provides a preparation method of a visual model of a complex-film oil and gas reservoir, the preparation method comprising:

[0009] obtaining model parameters having a similarity relationship with actual oil and gas reservoir parameters according to similarity criteria;

[0010] then constructing a visual model of a complex-film strong heterogeneity oil and gas reservoir according to the model parameters having a similarity relationship with the actual oil and gas reservoir parameters;

[0011] The similarity conditions for obtaining model parameters having a similarity relationship with actual oil and gas reservoir parameters according to similarity criteria include model geometric similarity, model boundary condition similarity, reservoir feature similarity, injection-production parameter similarity, fluid physical property similarity, and oil and gas miscible state similarity.

[0012] The preparation method provided by the present application, by means of the similarity principle, simulates the geological structure, fluid physical property, and production conditions of a complex-film strong heterogeneity oil and gas reservoir (i.e. an oil and gas reservoir containing three media of pores, cracks, and caves), provides a two-dimensional visual physical model preparation method for a complex-film strong heterogeneity oil and gas reservoir in indoor experimental research, and the obtained model can be used for displacement experiments, filling the gap in the preparation method of a model for simulating a complex-film strong heterogeneity oil and gas reservoir, and providing an effective experimental model preparation method for indoor experimental research on a complex-film strong heterogeneity oil and gas reservoir in the form of two-dimensional visualization.

[0013] As a preferred technical solution of the present application, the model geometric similarity includes proportionally reducing the size of the actual complex-film strong heterogeneity oil and gas reservoir, and proportionally reducing the complex-film characteristics of the oil and gas reservoir and the position relationship of injection and production wells in the model.

[0014] As a preferred technical solution of the present application, the model boundary condition similarity includes arranging the position of the simulated injection and production wells to be connected with the outside world, and sealing the remaining positions.

[0015] As the preferred technical scheme of the present application, the reservoir feature similarity comprises mapping the spatial distribution of the actual oil and gas reservoir complex facies factors into the model in proportion, so that the complex facies features embodied by the model are similar to the actual complex facies strong heterogeneous oil and gas reservoir.

[0016] As the preferred technical scheme of the present application, the injection-production parameter similarity comprises determining the simulated injection-production well production pressure difference of the experiment and confirming the simulated production time and simulated injection speed according to the similar coefficients when performing the displacement experiment by using the visualized model of the complex facies strong heterogeneous oil and gas reservoir.

[0017] Preferably, the simulated production time t 模拟 is calculated according to the following formula:

[0018]

[0019] In the formula, f(L) is the ratio of the model length to the average single-well control length of the actual oil reservoir, f(H) is the ratio of the model thickness to the average single-well control thickness of the actual oil reservoir, t 实际 is the production time of the actual oil reservoir, and day.

[0020] Preferably, the simulated injection speed Q 模型 (mL / min) is calculated according to the following formula:

[0021] Q 模型 = Q 实际 × f(L) × f(H);

[0022] In the formula, f(L) is the ratio of the model length to the average single-well control length of the actual oil reservoir, f(H) is the ratio of the model thickness to the average single-well control thickness of the actual oil reservoir, Q 实际 is the injection speed of the actual oil reservoir, and m 3 / day.

[0023] As the preferred technical scheme of the present application, the fluid property similarity comprises preparing the simulated experiment oil with a viscosity similar to that of the actual oil and gas reservoir.

[0024] As the preferred technical scheme of the present application, the oil and gas miscibility state similarity comprises simulating the miscible flooding and immiscible flooding processes according to the actual oil and gas reservoir state.

[0025] As the preferred technical scheme of the present application, the complex facies strong heterogeneous oil and gas reservoir visualized model constructed according to the model parameters having the similar relationship with the actual oil and gas reservoir parameters comprises a closed rigid structure and a matrix layer.

[0026] Preferably, the model parameter constructing process according to the similar relationship with the actual oil and gas reservoir parameters is as follows: taking a metal frame as a main body, installing a tempered visual glass plate on the front of the frame, arranging a sealing ring and a gasket between the frame and the glass plate, then internally cementing the metal frame, the tempered glass and the matrix layer with resin, and sealing and reinforcing the frame front installation with fasteners and sealing the matrix layer.

[0027] Preferably, the metal frame and the tempered visual glass are bonded by using resin glue.

[0028] Preferably, the fastener comprises a bolt.

[0029] Preferably, the visual model of the complex-film-state strong heterogeneous oil and gas reservoir is used to simulate the matrix characteristics, fracture characteristics and cave characteristics of the oil and gas reservoir.

[0030] As a preferred technical solution of the present application, the closed rigid structure is provided with a visual window.

[0031] Preferably, the matrix layer comprises quartz sand, resin glue, metal wire and paraffin wax.

[0032] Preferably, the metal wire such as stainless steel wire is used to simulate fracture structure; the paraffin wax is used to simulate cave structure in the oil reservoir; and the resin glue is used to glue the quartz sand.

[0033] In the second aspect, the present application provides a use of the visual model of the complex-film-state strong heterogeneous oil and gas reservoir prepared by the preparation method of the first aspect, and the use comprises using the visual model of the complex-film-state strong heterogeneous oil and gas reservoir to study the recovery rate and the interface dynamic change rule of the underground oil and gas under different production conditions, and the wave and characteristic of the fluid in different media.

[0034] Compared with the prior art, the present application has the following beneficial effects:

[0035] (1) The preparation method provided by the present application can effectively simulate the geological structure conditions and production conditions of the actual complex-film-state strong heterogeneous oil and gas reservoir in the laboratory by the similarity principle, and simulate the complex-film-state structure characteristics.

[0036] (2) The two-dimensional visual physical model obtained by the present application can enable researchers to more intuitively observe the interface dynamic change rule of the displacement phase and the displaced phase and the wave and characteristic of the displacement fluid in the model, and truly simulate the production process of the actual complex-film-state strong heterogeneous oil and gas reservoir.

[0037] (3) The preparation method provided by the present application can realize the similar simulation of key factors such as temperature, pressure, complex-film-state characteristics and fluid physical characteristics of the actual complex-film-state strong heterogeneous oil and gas reservoir. BRIEF DESCRIPTION OF DRAWINGS

[0038] Figure 1 is a schematic diagram of a single-layer complex-film state strong heterogeneity visual model in an embodiment of the present application;

[0039] Figure 2 is a schematic diagram of a horizontal double-layer complex-film state strong heterogeneity visual model in an embodiment of the present application;

[0040] Figure 3 is a schematic diagram of a tilt-angle double-layer complex-film state strong heterogeneity visual model in an embodiment of the present application;

[0041] Figure 4 is a photo of a strong heterogeneity oil and gas reservoir complex-film state visual model obtained in Embodiment 1 of the present application;

[0042] Figure 5 is a photo of a sand layer of a strong heterogeneity oil and gas reservoir complex-film state visual model obtained in Embodiment 1 of the present application;

[0043] Figure 6 is a photo of a sand layer when the volume ratio HCPV of injected carbon dioxide to model pores is 0.01 in a strong heterogeneity oil and gas reservoir complex-film state visual model obtained in Embodiment 1 of the present application;

[0044] Figure 7 is a photo of a sand layer when the volume ratio HCPV of injected carbon dioxide to model pores is 0.02 in a strong heterogeneity oil and gas reservoir complex-film state visual model obtained in Embodiment 1 of the present application;

[0045] Figure 8 is a photo of a sand layer when the volume ratio HCPV of injected carbon dioxide to model pores is 0.07 in a strong heterogeneity oil and gas reservoir complex-film state visual model obtained in Embodiment 1 of the present application;

[0046] Figure 9 is a photo of a sand layer when the volume ratio HCPV of injected carbon dioxide to model pores is 0.11 in a strong heterogeneity oil and gas reservoir complex-film state visual model obtained in Embodiment 1 of the present application;

[0047] Figure 10 is a photo of a sand layer when the volume ratio HCPV of injected carbon dioxide to model pores is 0.24 in a strong heterogeneity oil and gas reservoir complex-film state visual model obtained in Embodiment 1 of the present application;

[0048] Figure 11 is a photo of a sand layer when the volume ratio HCPV of injected carbon dioxide to model pores is 0.44 in a strong heterogeneity oil and gas reservoir complex-film state visual model obtained in Embodiment 1 of the present application;

[0049] Figure 12is a photo of the sand layer when the volume ratio HCPV of the injected carbon dioxide to the model pore in the complex membrane state strong heterogeneous oil and gas reservoir visualization model obtained in embodiment 1 of the present application is 0.99;

[0050] Figure 13 is a photo of the sand layer when the volume ratio HCPV of the injected carbon dioxide to the model pore in the complex membrane state strong heterogeneous oil and gas reservoir visualization model obtained in embodiment 1 of the present application is 10.09.

[0051] The present application is further described in detail below. However, the examples described below are merely simple examples of the present application and do not represent or limit the protection scope of the present application, and the protection scope of the present application is subject to the claims. DETAILED DESCRIPTION

[0052] To better illustrate the present application and facilitate understanding of the technical solutions of the present application, the typical but non-limiting embodiments of the present application are as follows:

[0053] The present embodiment provides a preparation method of a complex membrane state oil and gas reservoir visualization model, and the preparation method comprises:

[0054] According to the similarity criterion, the model parameters having the similarity relationship with the actual oil and gas reservoir parameters are obtained;

[0055] Then, the complex membrane state strong heterogeneous oil and gas reservoir visualization model is constructed according to the model parameters having the similarity relationship with the actual oil and gas reservoir parameters.

[0056] The similarity conditions for obtaining the model parameters having the similarity relationship with the actual oil and gas reservoir parameters according to the similarity criterion include model geometric similarity, model boundary condition similarity, reservoir feature similarity, injection-production parameter similarity, fluid physical property similarity and oil-gas miscible state similarity.

[0057] The model geometric similarity includes that the actual complex membrane state strong heterogeneous oil and gas reservoir is proportionally reduced in size, and the complex membrane state characteristics and injection-production well position relationship of the oil and gas reservoir are proportionally reduced and set in the model.

[0058] Specifically, the size of the two-dimensional visualization physical model is proportionally reduced according to the size of the actual oil and gas reservoir. The strong heterogeneity of the oil and gas reservoir is also proportionally reduced and reflected in the model. The position relationship of the simulated injection-production wells is arranged in the model according to the proportion of the injection-production well position in the actual oil and gas reservoir.

[0059] The model boundary condition similarity includes that the position of the simulated injection-production well is connected with the outside world, and the remaining positions are sealed.

[0060] Specifically, the four sides of the two-dimensional visual physical model are sealed by stainless steel frames and dead plugs, the front and back sides are sealed by solidified epoxy resin, and the outer boundary conditions of the actual oil and gas reservoir closed boundary can be simulated. The simulated injection and production well is arranged to be in communication with the displacement pump, gas source or fluid metering system to realize the simulation of constant pressure or constant flow production. The experimental temperature simulates the actual oil and gas reservoir temperature.

[0061] In the present application, the simulated injection and production well is arranged to be in communication with the displacement pump, gas source or fluid metering system to realize the simulation of constant pressure or constant flow production, and the experimental temperature simulates the actual oil and gas reservoir temperature.

[0062] The reservoir characteristics similar include that the spatial distribution of the actual oil and gas reservoir complex state factors is mapped into the model in proportion, so that the complex state characteristics embodied by the model are similar to the strong heterogeneous oil and gas reservoir.

[0063] Specifically, in the process of making the two-dimensional visual physical model, objects similar to the strong heterogeneous factors such as fractures, interlayers, multiple layers, dip angles, faults and solution cavities in the actual oil and gas reservoir are used, and the spatial distribution of these strong heterogeneous factors in the actual oil and gas reservoir is mapped into the model in proportion, so that the strong heterogeneity embodied by the model is similar to the actual oil and gas reservoir.

[0064] The injection and production parameter similar includes that when the displacement experiment is carried out by using the complex state strong heterogeneous oil and gas reservoir visual model, the simulated injection and production well production pressure difference is determined according to the actual oil and gas reservoir interwell pressure gradient or injection and production speed conversion, and the simulated production time and simulated injection speed are confirmed according to the similarity coefficient.

[0065] In the present application, the simulated production time t 模拟 is calculated according to the following formula:

[0066]

[0067] In the formula, f(L) is the ratio of the model length to the average single well control length of the actual oil reservoir, f(H) is the ratio of the model thickness to the average single well control thickness of the actual oil reservoir, t 实际 is the production time of the actual oil reservoir, days.

[0068] In the present application, the simulated injection speed Q 模型 (mL / min) is calculated according to the following formula:

[0069] Q 模型 = Q 实际 × f(L) × f(H);

[0070] Wherein, f(L) is the ratio of model length and actual oil reservoir average single well control length, f(H) is the ratio of model thickness and actual oil reservoir average single well control thickness, Q 实际 is the injection rate of actual oil reservoir, m 3 / day.

[0071] The fluid physical property similarity includes preparing simulation experiment oil with similar viscosity to the actual oil and gas reservoir.

[0072] Specifically, due to the limitation of the pressure bearing capacity of the two-dimensional visual physical model, it is necessary to prepare simulation experiment oil with similar viscosity to the actual oil and gas reservoir to ensure the similarity of fluid properties in the model, and the calculation formula of each fluid property parameter is as follows:

[0073] The composition of crude oil is: π2=ω i ,(i=1,2,3……,n,j=1,2,3,m=1,2,3)

[0074] Mobility ratio:

[0075] Density number:

[0076] Wherein, is the molar concentration of i component in j phase, is the molar concentration of i component in m phase, ω i is the component eccentricity factor, K ri is the relative permeability of i phase, μ i is the viscosity of i phase, ρ i is the density of i phase.

[0077] In the present application, the physical parameters such as the composition of simulation experiment oil, mobility ratio and density number are the same as those of the actual oil and gas reservoir.

[0078] The oil and gas miscible state similarity includes simulating miscible flooding and non-miscible flooding process according to the actual oil and gas reservoir state.

[0079] Specifically, the two-dimensional visual physical model can realize CO2 supercritical state under existing experimental conditions, simulate miscible flooding and non-miscible flooding process, and the calculation formula of oil and gas miscible state is:

[0080] Diffusion ratio: (i=1,2,3……,n,j=1,2,3,m=1,2,3……,n)

[0081] Capillary number (influence of oil and gas interfacial tension):

[0082]

[0083] where Dijis the diffusion coefficient of the i component in the j phase, Dmjis the diffusion coefficient of the m component in the j phase, φ is the porosity, v is the injection velocity, σ is the interfacial tension, and γ is the contact angle. ij where Dijis the diffusion coefficient of the i component in the j phase, Dmjis the diffusion coefficient of the m component in the j phase, φ is the porosity, v is the injection velocity, σ is the interfacial tension, and γ is the contact angle. mj where Dijis the diffusion coefficient of the i component in the j phase, Dmjis the diffusion coefficient of the m component in the j phase, φ is the porosity, v is the injection velocity, σ is the interfacial tension, and γ is the contact angle. inj where Dijis the diffusion coefficient of the i component in the j phase, Dmjis the diffusion coefficient of the m component in the j phase, φ is the porosity, v is the injection velocity, σ is the interfacial tension, and γ is the contact angle. j(i-1) where Dijis the diffusion coefficient of the i component in the j phase, Dmjis the diffusion coefficient of the m component in the j phase, φ is the porosity, v is the injection velocity, σ is the interfacial tension, and γ is the contact angle.

[0084] Exemplarily, the physical model can be designed to have single-layer or multi-layer rock layer distribution, double or multiple medium distribution. However, considering that the actual oil and gas reservoir geological structure is relatively complex, if each non-homogeneous factor in the oil and gas reservoir is reflected in the model design, the model will face great difficulties in making. Moreover, the visual size of the model is limited, and if each non-homogeneous factor of the actual oil and gas reservoir is proportionally reduced and mapped in the model, the individual small non-homogeneous factor will not have obvious influence on the overall effect of the experiment and has no practical significance, so in the model design, no more than 5 strong non-homogeneous factors (including fractures, solution cavities, faults, dip angles, etc.) are embodied in each model, and the remaining secondary factors are simplified or ignored.

[0085] Three strong non-homogeneous two-dimensional visual physical model designs of complex film state are shown below.

[0086] The two-dimensional visual physical model is 20 cm long, 15 cm wide, and 0.6 cm thick, and the visual area of the whole model is 300 cm 2 . Figure 1 It is a single-layer complex film state strong non-homogeneous visual model design diagram. The model uses 120-140 mesh quartz sand as the reservoir matrix, with a porosity of 26.3% and a permeability of 2.1 mD. Three structural fractures are arranged in the matrix, two of which are arranged in cross and each has a branch fracture, and the other structural fracture connects four branch fractures, and a plurality of solution cavities are arranged in the whole model area. The total pore volume of the model is 78.9 cm 3 . One injection well is arranged at the center of the top end of the model, and one production well is arranged at the center of the bottom end, realizing the gravity drive injection and production mode of top injection and bottom production.

[0087] Figure 2 It is a horizontal double-layer complex film state strong non-homogeneous visual model design diagram. The horizontal double-layer model is based on the single-layer model, and the matrix is evenly divided into upper and lower two layers. The upper layer uses 120-140 mesh quartz sand as the matrix, and the lower layer uses 80-100 mesh quartz sand. The porosities are 26.5% and 29.8% respectively, and the permeabilities are 2.1 mD and 3.2 mD respectively. The arrangement of fractures and solution cavities, and the arrangement position of injection wells and production wells are consistent with those of the single-layer model. The total pore volume of the model is 84.45 cm 3 .

[0088] Figure 3A design drawing of a dip angle double-layer complex film strong heterogeneity visual model is provided. The dip angle double-layer model is obtained by rotating the boundary between the upper and lower layers of the matrix by about 30 degrees clockwise from the center on the basis of the horizontal double-layer model, and the porosity and permeability of the two layers of the matrix are consistent with those of the horizontal double-layer model, so as to simulate the dip angle of the formation, and a non-permeable layer with a triangular area is arranged at the upper right and lower left corners of the model, the fracture and cave are arranged, and the injection well and production well are arranged at the same positions. 3 .

[0089] In the present application, the complex film strong heterogeneity oil and gas reservoir visual model constructed according to the model parameters having a similar relationship with the actual oil and gas reservoir parameters comprises a sealed rigid structure and a matrix layer.

[0090] The model parameter construction process according to the similar relationship with the actual oil and gas reservoir parameters is as follows: a metal frame is used as the main body, tempered visible glass plates are installed on the front of the frame, sealing rings and gaskets are arranged between the frame and the glass plates, then the metal frame, tempered glass and matrix layer are cemented with resin inside, and the frame front installation is reinforced and sealed with fasteners and the matrix layer is sealed.

[0091] The metal frame and the tempered visible glass are bonded by using resin glue.

[0092] The fastener comprises a bolt.

[0093] The complex film strong heterogeneity oil and gas reservoir visual model is used to simulate the matrix characteristics, fracture characteristics and cave characteristics of the oil and gas reservoir.

[0094] The sealed rigid structure is provided with a visual window.

[0095] The matrix layer comprises quartz sand, resin glue, metal wire and paraffin.

[0096] The metal wire is used to simulate the fracture structure in the oil reservoir, and the paraffin is used to simulate the cave structure in the oil reservoir.

[0097] Specifically, the metal wire such as stainless steel wire and other commonly used metal wires in the art is selected.

[0098] The sealed rigid structure is sealed by using sealing rings, gaskets and bolts.

[0099] The side of the closed rigid structure is provided with an access opening for installing pipelines, and is further communicated with a gas source and a production metering end, and a plurality of injection-production mode combinations can be formed through system regulation, import and export valve control and pipeline connection design, and the dynamic change law of the displacement phase and the displaced phase interface and the sweep characteristics of the displacement fluid in the model can be directly observed, and the displacement law of the formation fluid in the matrix, the fracture and the cave in the actual complex state strong heterogeneous oil and gas reservoir exploitation process can be simulated.

[0100] Exemplarily, a stainless steel frame is taken as a main body, tempered visible glass plates are installed on the front of the frame, rubber sealing rings and asbestos gaskets are padded between the frame and the glass plates, and the front of the frame is installed and reinforced for sealing with screws; the inside is cemented with resin, stainless steel frame, tempered glass and quartz sand, and the quartz sand is sealed; the back is sealed with resin glue, and rubber gaskets are padded between the solidified resin glue and the stainless steel cover plate, and the back of the frame is installed and reinforced for sealing with screws. The access openings around the frame can be installed with pipelines, which are communicated with a gas source and a production metering end, and a plurality of injection-production mode combinations can be formed through system regulation, import and export valve control and pipeline connection design, as shown in Figure 4 .

[0101] Specifically, the tempered glass plates are installed on clean stainless steel frames, rubber sealing rings and asbestos gaskets are padded between the glass plates and the stainless steel frames, and the frame and the glass plate are pressurized and fixed with screws. Resin glue mixed and stirred at a ratio of 3:1 and then left to stand is poured on the inner surface of the glass plate, and the resin glue is completely solidified.

[0102] The purpose of pouring the resin glue is to firmly cement the glass plate and the frame, so as to prevent fluid leakage in the model during the experiment; since the resin glue is colorless and transparent, it can better cement the materials in the sand filling model such as sand particles, and also ensure the observation effect of the swept characteristics of the injected gas during gas injection displacement.

[0103] Further, the fixing of the glass plate and the frame can also be realized by using other fixing and sealing methods.

[0104] Before pouring, it is necessary to pay attention to keep the frame horizontal, and after pouring, the bubbles of the resin glue are removed, and the surface of the resin glue is kept flat, smooth and dust-free.

[0105] The metal frame provided by the present application is provided with a plurality of access holes around the frame (such as the upper side, the lower side, the left side and the right side), which can directly communicate with the sand filling model area, and thus meet the design requirements of different injection and production well positions. According to the model design drawing, pipelines and valves are installed at the simulated injection and production well arrangement positions outside the four sides of the model, and the valves are closed. Before the experiment, the pipelines are connected to the experimental equipment at the injection end and the production end respectively. The remaining access hole positions around the model are sealed with dead plugs to prevent fluid leakage in the model during the experiment.

[0106] The quartz sand of 120-140 mesh is selected and added with a proper amount of resin glue for stirring until the sand and glue are uniformly and sufficiently mixed. Then the stirred sand is filled on the surface of the completely solidified resin glue, and the sand is evenly knocked with a hammer so as to be filled and compacted in the model. The filled sand is used as the matrix in the model.

[0107] The purpose of mixing and stirring the quartz sand with the resin glue is to cement the sand particles to form a stable and firm matrix model. In addition, the sand particles and the solidified resin glue on the glass plate are also cemented to ensure the observation effect of the swept characteristics in the gas displacement experiment.

[0108] The metal mesh with a larger mesh number is used as the fracture structure for simulating the actual strong heterogeneous oil and gas reservoir, and the wax block is used as the simulation cave. The wax block is arranged in the matrix of the model according to the spatial distribution position of the design drawing. The pressure plate and the cover plate are added on the surface of the filled model matrix, and the entire stainless steel frame is fixed by screwing and pressing, and is placed to achieve the purpose of compacting and firmly cementing the model.

[0109] When the quartz sand and the resin glue are mixed and stirred, attention should be paid to controlling the ratio of sand and glue. Specifically, the mass ratio of quartz sand and resin is (7-9):1. If the glue is too much, the pores and crack channels in the sand will be blocked by the glue, reducing the flowability of the model. If the glue is too little, the sand in the model will move during the experiment, and the pipeline will be blocked, damaging the experimental effect. When the surface of the sand is knocked with a hammer, attention should be paid to uniform force, otherwise the cementation of the sand and the glue on the surface will be poor, which will affect the experimental effect.

[0110] The screws on the back of the stainless steel frame are removed, the pressure plate and the cover plate are opened, the completely stirred resin glue is poured on the surface of the model matrix, and is placed to wait for solidification, so that the glue completely seals the surface of the matrix. When the glue is completely solidified, the rubber pad is laid on the surface, the cover plate is added, and the entire model is fixed by screwing and pressing.

[0111] The purpose of pouring the resin glue is to prevent the fluid in the model from leaking from the back of the model during the experiment.

[0112] Before pouring the resin glue, it is necessary to ensure that the model is horizontal, and attention should be paid to not allowing the glue to penetrate into the matrix, so as to avoid blocking the pores and crack channels and hindering the flow of fluid in the model.

[0113] The model is obtained by curing, N2 source and pressure gauge are connected outside the model to fill N2 in the model to test the pressure, for example, N2 source and pressure gauge are connected with the injection well of the model, only the injection well valve is opened, and the remaining valves are kept closed, N2 is slowly injected into the model, when the pressure in the model rises to the experimental pressure, the injection well valve is closed, the pressure in the model is stabilized at the experimental pressure, and the model is placed for about 1 hour, and whether the pressure in the model decreases is observed. If it does not decrease, it means that the model has good sealing performance, that is, it can pass the pressure test and can be tested; if it decreases, it means that the model leaks, the leakage position needs to be found out and the sealing is further consolidated, and the pressure test is performed again until no leakage occurs.

[0114] Wherein, when N2 is injected, a small pressure is required to slowly inject, so as to prevent the model from being damaged due to too fast pressure change.

[0115] The specific example of the model manufacturing process is as follows:

[0116] ①Install tempered glass and inject epoxy resin to seal;

[0117] ②Mix quartz sand and epoxy resin and fill them into the stainless steel frame after uniform stirring, and uniformly pressurize and fill flat;

[0118] ③After injecting epoxy resin to seal the model, the cover plate is reinforced and sealed with screws;

[0119] ④Connect N2 source and pressure gauge outside the model to fill N2 in the model to test the pressure.

[0120] Further, in order to illustrate the effect that the model obtained by the preparation method of the visual model of the complex-film oil and gas reservoir provided by the application can achieve, an actual example is used for specific description, which is as follows:

[0121] Example 1

[0122] Because the factors influencing crude oil production, such as geological structure characteristics, heterogeneity characteristics, fluid physical property characteristics, well pattern and well spacing distribution, dynamic production characteristics and the like of actual oil and gas reservoirs are very complex, the current laboratory experiment can only simulate the main characteristics of the actual oil and gas reservoir on the basis of basic assumptions, and the model is maximally simplified to achieve the purpose of simulating the development law of the actual oil and gas reservoir. Taking the inverted nine-point 1 / 4 well pattern of H46 test area in Jilin Oilfield as an example, the parameters of the CO2 areal displacement two-dimensional physical simulation experiment are calculated.

[0123] S1, length and thickness simulation

[0124] The average single well control length of H46 in Jilin Oilfield is about 384 m, the average thickness is 8 m, the length of the two-dimensional simulation model is 20 cm, and the thickness is 10 cm, according to the criterion relationship:

[0125]

[0126]

[0127] S2, production time simulation

[0128] The field production time of Jilin oilfield is 20a, then:

[0129]

[0130] S3, injection rate simulation

[0131] The field injection rate is 20m 3 / d, then:

[0132] Q 模型 = Q 原型 x f(L) x f(H) = 0.0927 mL / min

[0133] S4, other condition simulation

[0134] The conditions such as reservoir pressure, reservoir temperature, crude oil viscosity, porosity and so on are the same as the prototype conditions.

[0135] Finally, the comparison of the experimental parameters of the reservoir and the model is shown in Table 1.

[0136] Table 1

[0137] Production index Reservoir number Model number Whether similar Interwell distance 384m 20 cm Similar Effective thickness 8m 10 cm Similar Reservoir pressure 23 MPa 23 MPa Similar Reservoir temperature 96.7℃ 96.7℃ Similar Crude oil viscosity 1.85 mPa s 1.85 mPa s Similar CO2 viscosity 0.0432 mPa s 0.0432 mPa s Similar Porosity 13.07％ 13％ Similar Permeability 2.93 mD 2.93 MD Similar Injection rate 20m 3 / d]] 0.0927 mL / min Similar Production time 20a 18.615d Similar Heterogeneity Fracture development, large difference between fracture and matrix permeability - Similar

[0138] The top injection end of the completed single-layer complex-film two-dimensional visual model is connected to the gas source, and the bottom production end is connected to the metering device, and the gas drive experiment is carried out to study the oil displacement effect of gas injection under constant production rate. A high-speed camera is erected in the direction of the visual surface of the model, and the camera is controlled by computer software to take pictures at an average time interval of 150s to record and observe the sweep characteristics of injected gas and the dynamic changes of oil-gas interface under two-dimensional conditions, as well as the production rules of oil and gas in matrix, fractures and caves. The following is the experimental result display.

[0139] Before the start of the gas drive experiment, the model is saturated with oil, and the pressure in the model is stabilized near the experimental pressure to simulate the environment of the actual undeveloped complex-film strong heterogeneous reservoir Figure 5 ). Open the injection end and production end valves to start the gas drive experiment, and record the oil and gas production at an interval of every 5min. According to the high-speed camera recording, it can be seen that at the beginning of the experiment, the injected gas uniformly drives out the oil in the matrix of the model, and the oil-gas interface gradually appears and begins to spread downward Figure 6 ). When the injected gas reaches the fracture and cave structure, it begins to preferentially drive out the oil in the fractures and caves, and establishes a gas flow dominant channel in the fractures Figure 7). The gas that reaches the bottom of the fracture first further displaces the oil in the matrix downward. Meanwhile, the oil in the matrix at the top of the model is also continuously displaced downward Figure 8 and Figure 9 ). When the gas reaches the bottom of the fracture, it can be observed that the gas overcomes the effect of gravity and preferentially establishes a dominant channel upward along the fracture Figure 10 ). The oil in the matrix at the lower part of the fracture is then continuously displaced along the dominant channel, while the oil in the matrix at the upper part of the fracture is rarely swept Figure 11 and Figure 12 ). Finally, when the HCPV is 10.09, the gas-oil ratio reaches 1000 or more, and the experiment ends, as shown in Figure 13 .

[0140] After the end, it can be observed that there is a large area of remaining oil in the matrix at the upper part of the fracture of the model, indicating that the fracture structure affects the sweep rule of the injected gas.

[0141] In the present application, the HCPV is the volume ratio of the injected carbon dioxide in the model to the pore volume of the model.

[0142] It is stated that the present application illustrates the detailed structural features of the present application through the above-mentioned embodiments, but the present application is not limited to the above-mentioned detailed structural features, i.e. it does not mean that the present application must rely on the above-mentioned detailed structural features to be implemented. It should be understood by those skilled in the art that any improvement of the present application, equivalent replacement of the components selected by the present application, addition of auxiliary components, selection of specific modes, etc. fall within the protection scope and disclosure scope of the present application.

[0143] The preferred embodiments of the present application are described in detail above, but the present application is not limited to the specific details in the above-mentioned embodiments. Within the technical concept scope of the present application, various simple modifications can be made to the technical solutions of the present application, and these simple modifications all belong to the protection scope of the present application.

[0144] In addition, it should be noted that each specific technical feature described in the above-mentioned specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present application will not further describe various possible combination manners.

[0145] In addition, various different embodiments of the present application can also be combined in any manner, as long as it does not deviate from the idea of the present application, and it should be considered as the disclosed content of the present application.

Claims

1. A method for preparing a visualization model of a complex film-like oil and gas reservoir, characterized in that, The preparation method includes: Model parameters that are similar to actual oil and gas reservoir parameters are obtained based on similarity criteria; Then, a visualization model of a complex film-state highly heterogeneous oil and gas reservoir was constructed based on model parameters that have similar relationships to actual oil and gas reservoir parameters; Among them, the similarity conditions for obtaining model parameters that have similarity with actual oil and gas reservoir parameters according to similarity criteria include model geometric similarity, model boundary condition similarity, reservoir characteristic similarity, injection and production parameter similarity, fluid property similarity, and oil and gas miscibility state similarity.

2. The preparation method according to claim 1, characterized in that, The geometric similarity of the model includes scaling down the actual size of the complex film-formed, highly heterogeneous oil and gas reservoir, while also scaling down the complex film-formed characteristics of the reservoir and the positional relationship between injection and production wells in the model.

3. The preparation method according to claim 1 or 2, characterized in that, The model boundary conditions similarity include arranging the locations of simulated injection and production wells to be connected to the outside, while the remaining locations are sealed.

4. The preparation method according to any one of claims 1-3, characterized in that, The similarity of reservoir characteristics includes mapping the spatial distribution of the complex film state factors of actual oil and gas reservoirs into the model in a proportional manner, so that the complex film state characteristics reflected in the model are similar to those of actual complex film state strongly heterogeneous oil and gas reservoirs.

5. The preparation method according to any one of claims 1-4, characterized in that, The similarity of injection and production parameters includes, when conducting displacement experiments using a visualization model of a complex-film, highly heterogeneous oil and gas reservoir, determining the simulated production pressure difference between injection and production wells based on the actual oil and gas reservoir well pressure gradient or injection and production rate, and confirming the simulated production time and simulated injection rate based on the similarity coefficient. Preferably, the simulated production time t 模拟 The calculation formula is as follows: t 模拟 =t 实际 ×√f(L)×f(H) In the formula, f(L) is the ratio of the model length to the average control length of a single well in the actual reservoir, f(H) is the ratio of the model thickness to the average control thickness of a single well in the actual reservoir, and t 实际 The actual production time of the reservoir is in days; Preferably, the simulated injection rate Q 模型 The formula for calculating (mL / min) is as follows: Q 模型 =Q 实际 ×f(L)×f(H); In the formula, f(L) is the ratio of the model length to the average control length of a single well in the actual reservoir, f(H) is the ratio of the model thickness to the average control thickness of a single well in the actual reservoir, and Q... 实际 m represents the actual injection rate of the reservoir. 3 / sky.

6. The preparation method according to any one of claims 1-5, characterized in that, The fluid property similarity includes preparing experimental oil with a viscosity similar to that of crude oil from actual oil and gas reservoirs.

7. The preparation method according to any one of claims 1-6, characterized in that, The similarity of oil and gas miscibility states includes simulating miscible and immiscible flooding processes based on the actual oil and gas reservoir conditions.

8. The preparation method according to any one of claims 1-7, characterized in that, The visualization model of a complex film-like, highly heterogeneous oil and gas reservoir, constructed based on model parameters that have a similar relationship with actual oil and gas reservoir parameters, includes a closed rigid structure and a matrix layer. Preferably, the process of constructing model parameters based on parameters similar to those of actual oil and gas reservoirs is as follows: a metal frame is used as the main body, a tempered glass plate is installed on the front of the frame, a sealing ring and a gasket are arranged between the frame and the glass plate, and then the metal frame, tempered glass and matrix layer are bonded with resin inside, and the front of the frame is reinforced and sealed with fasteners and the matrix layer is sealed. Preferably, the metal frame and the tempered viewing glass are bonded together using resin adhesive; Preferably, the fastener includes a bolt; Preferably, the visualization model of the complex film-like highly heterogeneous oil and gas reservoir is used to simulate the matrix characteristics, fracture characteristics, and cavern characteristics of the oil and gas reservoir.

9. The preparation method according to claim 8, characterized in that, The sealed rigid structure is provided with a viewing window; Preferably, the matrix layer comprises quartz sand, resin adhesive, metal wire, and paraffin wax; Preferably, the metal wire is used to simulate fracture structures in an oil reservoir; the paraffin wax is used to simulate cave structures in an oil reservoir; and the resin adhesive is used to bond the quartz sand.

10. The use of a visualization model of a highly heterogeneous, multi-film oil and gas reservoir obtained by the preparation method according to any one of claims 1-9, characterized in that, The applications include using a visualization model of highly heterogeneous oil and gas reservoirs with complex film to study the recovery rate and interface dynamics of underground oil and gas under different extraction conditions, as well as the sweep characteristics of fluids in different media.

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