Quantitative characterization method and device for imbibition replacement effect, storage medium and processor

Abstract

The invention relates to the field of oil and gas reservoir development, and discloses an imbibition replacement effect quantitative characterization method and device, a storage medium and a processor, and the method comprises the steps: building an oil-water two-phase seepage mathematical model corresponding to a target flow field structure based on capillary action; solving the seepage mathematical model by using a finite difference method to obtain the change conditions of pressure and water saturation in each seepage region; according to the change condition, whether the imbibition replacement effect exists or not is judged; if the imbibition replacement effect exists, the contribution rate of the imbibition replacement effect to the tight oil reservoir development yield is determined based on a steady-state radial seepage mathematical model; and if the imbibition replacement effect does not exist, determining that the contribution rate of the imbibition replacement effect to the development yield of the tight oil reservoir is zero. Due to the fact that the imbibition and replacement effect can be quantitatively represented, the contribution rate of the imbibition and replacement effect to the development yield of the tight oil reservoir can be obtained, and therefore an actual exploitation scheme can be guided more accurately.

Description

Technical Field

[0001] This invention relates to the field of oil and gas reservoir development technology, specifically to a quantitative characterization method for permeation and displacement, a quantitative characterization device for permeation and displacement, a machine-readable storage medium, and a processor. Background Technology

[0002] Low-permeability tight oil reservoirs are rich in reserves, and the efficient development of such reservoirs is of great significance to ensuring energy security.

[0003] Due to the development of micro- and nano-sized pores in low-permeability tight reservoirs, both displacement and adsorption occur simultaneously during the development of these reservoirs. Therefore, when establishing a mathematical model of seepage in low-permeability tight reservoirs to simulate flow field changes during development, both displacement and adsorption are typically considered.

[0004] However, most tight oil reservoirs are currently developed using a depletion-based approach, with the seepage recovery process primarily characterized by seepage displacement. Existing simulation methods lack quantitative characterization of seepage displacement, making it impossible to determine its contribution to tight oil reservoir development and production, and consequently, failing to provide accurate guidance for actual production strategies. Summary of the Invention

[0005] The purpose of this invention is to overcome the problem of lack of quantitative characterization of permeation and displacement during the development of tight oil reservoirs in the prior art, and to provide a method, device, storage medium and processor for quantitative characterization of permeation and displacement.

[0006] To achieve the above objectives, a first aspect of the present invention provides a method for quantitative characterization of osmotic displacement, comprising:

[0007] A mathematical model of oil-water two-phase flow based on capillary action is established for the target flow field structure.

[0008] The mathematical model of the oil-water two-phase flow was solved using the finite difference method to obtain the pressure changes and water saturation changes in each flow zone.

[0009] Based on the changes in pressure and water saturation in each seepage zone, determine whether there is a seepage-replacement effect.

[0010] If percolation and displacement occur, the contribution rate of percolation and displacement to the development and production of tight oil reservoirs is determined based on the steady-state radial flow mathematical model; if percolation and displacement do not occur, the contribution rate of percolation and displacement to the development and production of tight oil reservoirs is determined to be zero.

[0011] In this embodiment of the application, the step of establishing a mathematical model for oil-water two-phase flow based on capillary action to correspond to the target flow field structure includes:

[0012] A mathematical model of oil-water two-phase flow is established based on the mass conservation equation, the relative permeability correlation equation, and the capillary force correlation equation.

[0013] In this embodiment, the capillary force-related equation is shown in the following formula:

[0014]

[0015] Where, p c Capillary pressure, unit: Pa; S w σ is the water saturation; J is the J function; θ is the wetting angle in °; σ is the interfacial tension in N / m; φ is the porosity of the rock; k is the permeability of the rock in m³. 2 a and b are constant terms.

[0016] In this embodiment of the application, determining whether there is a seepage displacement effect based on the changes in pressure and water saturation in each seepage zone includes:

[0017] If the production pressure difference between the first region and the second region is greater than the capillary pressure difference between the first region and the second region, then there is no percolation displacement effect;

[0018] If the production pressure difference between the first region and the second region is less than the capillary pressure difference between the first region and the second region, then there is a percolation and displacement effect.

[0019] The distance from the first region to the wellbore is less than the distance from the second region to the wellbore, and the water saturation of the first region is greater than that of the second region; the production pressure difference between the first region and the second region is obtained by subtracting the pressure of the first region from the pressure of the second region, and the capillary pressure difference between the first region and the second region is obtained by subtracting the capillary pressure of the first region from the capillary pressure of the second region.

[0020] In this embodiment of the application, determining the contribution rate of percolation and displacement to the development production of tight oil reservoirs based on a steady-state radial seepage mathematical model includes:

[0021] A steady-state radial seepage mathematical model was established for the target porous media unit;

[0022] The steady-state radial seepage mathematical model is solved to obtain the oil production per unit time;

[0023] Based on the oil production, the contribution rate of percolation and displacement to the development and production of tight oil reservoirs was obtained.

[0024] In this embodiment of the application, the oil production includes the oil production corresponding to pressure displacement and the oil production corresponding to percolation and displacement. The contribution rate of percolation and displacement to the development production of tight oil reservoirs is obtained based on the following formula:

[0025]

[0026] Wherein, γ represents the contribution rate of percolation and displacement to the development and production of tight oil reservoirs; Q o This represents the oil production corresponding to pressure differential displacement, in cubic meters (m³). 3 / s;Q o,im This represents the oil production corresponding to the percolation and displacement process, in m³. 3 / s;

[0027] Oil production Q corresponding to percolation displacement o,im Based on the following formula:

[0028]

[0029] Where k is the permeability of the rock, in meters. 2 ;k rw The relative permeability of the aqueous phase; ρ represents the average water saturation within the dynamic sweep range; h represents the formation thickness in meters; p c Capillary pressure, unit: Pa; S w,in The water saturation at the inner boundary; μ w The viscosity of the aqueous phase is expressed in Pa·s; r out r is the distance from the outer boundary to the wellbore, in meters (m). in This represents the distance from the inner boundary to the wellbore, in meters (m).

[0030] In this embodiment of the application, the method further includes:

[0031] To determine how the contribution of percolation and displacement in each seepage zone to the production of tight oil reservoirs varies with the development time.

[0032] A second aspect of the present invention provides a device for quantitative characterization of osmotic displacement, comprising:

[0033] The model building module is used to establish a mathematical model of oil-water two-phase flow based on capillary action to create a target flow field structure.

[0034] The solution module is used to solve the mathematical model of the oil-water two-phase flow using the finite difference method, and to obtain the pressure changes and water saturation changes in each seepage zone.

[0035] The judgment module is used to determine whether there is a seepage replacement effect based on the changes in pressure and water saturation in each seepage zone.

[0036] The contribution rate calculation module is used to determine the contribution rate of the seepage and replacement effect to the development and production of tight oil reservoirs based on the steady-state radial seepage mathematical model if seepage and replacement effect exists; if seepage and replacement effect does not exist, the contribution rate of seepage and replacement effect to the development and production of tight oil reservoirs is determined to be zero.

[0037] A third aspect of this application provides a processor configured to perform the above-described quantitative characterization method for osmotic displacement.

[0038] A fourth aspect of this application provides a machine-readable storage medium storing instructions that, when executed by a processor, configure the processor to perform the above-described quantitative characterization method for osmotic displacement.

[0039] The above technical solution includes: establishing a mathematical model of oil-water two-phase flow based on capillary action to correspond to the target flow field structure; solving the mathematical model using the finite difference method to obtain the pressure changes and water saturation changes in each seepage zone; determining whether percolation and displacement occur based on the pressure changes and water saturation changes in each seepage zone; if percolation and displacement occur, determining the contribution rate of percolation and displacement to the production of tight oil reservoirs based on the steady-state radial flow mathematical model; if percolation and displacement do not occur, determining that the contribution rate of percolation and displacement to the production of tight oil reservoirs is zero. Since the solution provided in this application can quantitatively characterize percolation and displacement and obtain the contribution rate of percolation and displacement to the production of tight oil reservoirs, it can provide more accurate guidance for actual production plans, which is of great significance for subsequent efficient development and improving the recovery rate of tight oil reservoirs.

[0040] Other features and advantages of the embodiments of this application will be described in detail in the following detailed description section. Attached Figure Description

[0041] The accompanying drawings are provided to further illustrate the embodiments of this application and form part of the specification. They are used together with the following detailed description to explain the embodiments of this application, but do not constitute a limitation on the embodiments of this application. In the drawings:

[0042] Figure 1 The schematic diagram illustrates a flow chart of a method for quantitative characterization of osmotic displacement according to an embodiment of this application;

[0043] Figure 2A schematic diagram of a target flow field structure physical model according to an embodiment of this application is shown.

[0044] Figure 3 This illustration schematically shows a diagram of relative permeability data of an oil-water two-phase system according to an embodiment of this application;

[0045] Figure 4 This illustration schematically shows a constant-rate mercury porosimetry experimental data diagram according to an embodiment of this application;

[0046] Figure 5 This illustration schematically shows the pressure field distribution and water saturation distribution at different development times according to an embodiment of this application;

[0047] Figure 6 This schematic diagram illustrates a permeation-displacement mechanism according to an embodiment of this application.

[0048] Figure 7 This illustration schematically shows the contribution rate of percolation and displacement under different production pressure differentials and water saturation conditions according to an embodiment of this application.

[0049] Figure 8 This illustration shows a schematic diagram of the variation of the contribution rate of osmosis and displacement at different times according to an embodiment of this application;

[0050] Figure 9 This schematic diagram illustrates a structural block diagram of a quantitative characterization device for osmotic displacement according to an embodiment of this application;

[0051] Figure 10 The diagram illustrates the internal structure of a computer device according to an embodiment of this application.

[0052] Explanation of reference numerals in the attached figures

[0053] 210 - Model building module; 220 - Solution module; 230 - Judgment module; 240 - Contribution rate calculation module; A01 - Processor; A02 - Network interface; A03 - Internal memory; A04 - Display screen; A05 - Input device; A06 - Non-volatile storage medium; B01 - Operating system; B02 - Computer program. Detailed Implementation

[0054] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only for illustration and explanation of the embodiments of this application and are not intended to limit the embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0055] If the embodiments of this application involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. If the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed in this application.

[0056] As described in the background section, low-permeability tight oil reservoirs are abundant, and their efficient development is crucial for ensuring energy security. Due to the development of micro- and nano-sized pores in low-permeability tight reservoirs, both displacement and adsorption occur simultaneously during development. Therefore, when establishing a seepage mathematical model for low-permeability tight reservoirs to simulate flow field changes during development, both displacement and adsorption are typically considered. For example, Wang Xiangzeng et al. constructed a seepage model considering both adsorption and displacement, revealing that gentle water injection can improve the development effect of fractured low-permeability reservoirs; Li Shuai et al., through laboratory experiments and pore network models, clarified that the fracturing and shut-in process can significantly improve the reservoir stimulation and development effects of tight oil reservoirs. However, currently, tight oil reservoirs are mostly developed using a depletion-type development approach, achieving effective development through drainage after fracturing and shut-in, with the adsorption oil production process mainly manifesting as adsorption and displacement. Existing simulation methods lack quantitative characterization of adsorption-displacement effects (i.e., reverse adsorption where fracturing fluid penetrates deep into the formation and displaces formation fluids to the near-wellbore zone). For example, while Wang Fuyong et al. quantitatively evaluated the roles of adsorption and displacement in water injection development of low-permeability tight oil reservoirs based on a mathematical model considering both adsorption and displacement, this study primarily focused on unidirectional adsorption and could not evaluate the contribution rate of adsorption-displacement to the development process of tight oil reservoirs. In other words, the current lack of quantitative characterization of adsorption-displacement effects prevents the understanding of their contribution to the production of tight oil reservoirs, thus hindering effective guidance for actual production strategies.

[0057] To address this, one embodiment of this application provides a method for quantitatively characterizing permeation and displacement processes, which can be used to quantitatively characterize permeation and displacement processes during tight oil reservoir development. Specifically, this method can characterize the contribution of permeation and displacement processes to tight oil reservoir development. Figure 1 As shown, the quantitative characterization method for osmotic displacement may include the following steps:

[0058] Step 101: Establish a mathematical model of oil-water two-phase flow based on capillary action for the target flow field structure.

[0059] Among them, establishing the oil-water two-phase flow mathematical model corresponding to the target flow field structure based on capillary action can be understood as taking capillary action into account when establishing the oil-water two-phase flow mathematical model corresponding to the target flow field structure.

[0060] In this embodiment, the target flow field structure is a multi-scale flow field structure with nanoscale, microscale, and millimeter-scale fractures formed during the fracturing development of tight oil reservoirs. Specifically, the nanoscale fractures can be matrix pores, the microscale fractures can be fracturing-derived microfractures, and the millimeter-scale fractures can be fracturing fractures.

[0061] More specifically, the target flow field structure can be as follows: after volumetric fracturing of a tight oil reservoir, an artificial main fracture is formed. A large volume of fluid injected into the formation causes irregular derivative microfractures to form near the main fracture. These derivative microfractures intertwine with natural microfractures in the reservoir, forming a complex fracture network. Simultaneously, under the influence of formation energy, formation fluids flow from matrix zone III into fracturing zone II, then into the main fracture zone I, and finally into the wellbore. Figure 2 As shown. In Figure 2 In the diagram, the center of the ellipse is the wellbore, and a and b correspond to the major and minor axes of the ellipse, respectively, with units of meters (m). The subscript m corresponds to the matrix zone, n to the fracturing stimulation zone, and x... f The crack half-length is expressed in meters (m).

[0062] In this embodiment, the oil-water two-phase flow mathematical model is specifically an oil-water two-phase flow mathematical model coupled with multiple flow zones, which can also be called an oil-water two-phase multi-zone coupled flow mathematical model. The multiple flow zones include the main fracture zone, the fracturing stimulation zone, and the matrix zone.

[0063] When establishing the mathematical model of oil-water two-phase flow corresponding to the target flow field structure, it can be based on the mass conservation equation, the relative permeability related equation, and the capillary force related equation.

[0064] (i) Regarding the mass conservation equation:

[0065] The mass conservation equations can specifically include the oil phase mass conservation equation and the water phase mass conservation equation. The oil phase mass conservation equation can be shown as formula (1) below, and the water phase mass conservation equation can be shown as formula (2) below:

[0066]

[0067] In the above formula (1), ρ0 is the oil phase density, with units of kg / m³. 3 ;v o q represents the oil phase flow velocity, in m / s. o Oil phase flow rate, unit: m³ / s 3 / s; φ is the porosity of the rock, dimensionless; S o ρ represents oil saturation, which is dimensionless; t represents time, in seconds. In formula (2) above, ρ w This is the density of the aqueous phase, in kg / m³. 3 ;v w q represents the velocity of the water phase flow, in m / s. w The flow rate is for the aqueous phase, expressed in m³ / s. 3 / s;S w The value represents water saturation, which is dimensionless.

[0068] In formula (1) above, v0 can be obtained based on the oil phase motion equation, specifically, the oil phase motion equation is shown in formula (3) below; v in formula (2) above w It can be obtained based on the water phase motion equation, specifically, the water phase motion equation is shown in the following formula (4):

[0069]

[0070] In the above formula (3), k is the permeability of the rock, in meters. 2 ;k ro The relative permeability of the oil phase is dimensionless; μ o The viscosity of the oil phase is expressed in Pa·s; p o ρ is the oil phase pressure, in Pa. In formula (4) above, k rw The relative permeability of the aqueous phase is dimensionless; μ w The viscosity of the aqueous phase is expressed in Pa·s; p w This represents the pressure in the aqueous phase, measured in Pa.

[0071] When using the above formula for calculations, the rock and fluid in the reservoir can be considered as slightly compressible. Therefore, in the above formula, ρ... w ρ o , φ, μ o and μ wThe following formulas (5), (6), (7), (8), and (9) can be used respectively:

[0072] ρ w =ρ w (p w (5);

[0073] In formula (5), ρ w (P w ) represents ρ w With P w A changing function.

[0074] ρ o =ρ o (p o (6);

[0075] In formula (6), ρ o (P o ) represents ρ o With P o A changing function.

[0076] φ=φ(p o (7);

[0077] In formula (7), φ(P) o ) indicates that φ varies with P o A changing function.

[0078] μ o =μ o (p o (8);

[0079] In formula (8), μ o (P o ) represents μ o With P o A changing function.

[0080] μ w =μ w (p w (9);

[0081] In formula (9), μ w (P w ) represents μ w With P w A changing function.

[0082] Substituting the oil phase motion equation into the oil phase mass conservation equation yields the basic differential equation for the oil phase, as shown in formula (10) below; substituting the water phase motion equation into the water phase mass conservation equation yields the basic differential equation for the water phase, as shown in formula (11) below:

[0083]

[0084] In the above formula, S o and S w Having the relationship shown in the following formula (12), P o and P w The relationship is shown in the following formula (13):

[0085] S w +S o =1(12);

[0086] p o -p w =p c (13);

[0087] In the above formula (13), p c This represents capillary pressure, measured in Pa.

[0088] (ii) Equations related to relative permeability:

[0089] The relative permeability equations can specifically include oil-phase relative permeability equations and water-phase relative permeability equations. In this embodiment, the oil-phase relative permeability equations and water-phase relative permeability equations can be obtained by fitting core displacement experimental data based on the Pirson model. In a specific embodiment of this application, the oil-water two-phase relative permeability experimental data can be as follows: Figure 3 As shown.

[0090] The relative permeability equation for the oil phase can be shown in formula (14) below, and the relative permeability equation for the water phase can be shown in formula (15) below:

[0091]

[0092] In the above formula (14), S or S represents residual oil saturation, dimensionless; wi The bound water saturation is dimensionless; m and n are constants obtained through fitting, which can be obtained by fitting a curve measured in indoor experiments (this curve characterizes the relative permeability as a function of S). w (The changing relationship) is obtained.

[0093] by Figure 3 Taking the data as an example, through fitting and linear regression of indoor core experimental data, the relative permeability coefficient n of the oil phase in the matrix zone is 3.085, and the relative permeability coefficient m of the water phase in the matrix zone is 3.571; the relative permeability coefficient n of the oil phase in the fracture zone is 2.185, and the relative permeability coefficient m of the water phase in the fracture zone is 2.048.

[0094] (iii) Equations related to capillary forces:

[0095] In this embodiment, the capillary force correlation equation can be obtained by fitting constant-rate mercury intrusion porosimetry experimental data based on the Leverett model. In a specific embodiment of this application, the constant-rate mercury intrusion porosimetry experimental data can be as follows: Figure 4 As shown. Specifically, the osmotic displacement effect can be characterized by the capillary pressure curve obtained by fitting the constant-rate mercury intrusion experimental data. The capillary force correlation equation can be represented by the following formula (16):

[0096]

[0097] In the above formula (16), J is the J function, which is a dimensionless function proposed by Leverett to characterize the variation of capillary force with parameters such as rock porosity and interfacial tension; θ is the wetting angle, in °; σ is the interfacial tension, in N / m; a and b are constant terms obtained by fitting, which can also be called capillary force coefficients.

[0098] by Figure 4 Taking the data from the experiment as an example, by fitting the constant-rate mercury intrusion test data and the oil-water interfacial tension, the capillary force coefficient 'a' can be obtained as 1.7251 × 10⁻⁶. -2 b is -1.529.

[0099] In the embodiments of this application, the formation pressure in the initial state of the oil-water two-phase flow mathematical model is the initial formation pressure P. s The water saturation is the bound water saturation. Therefore, the initial conditions for the mathematical model of oil-water two-phase flow can be shown in the following formula (17):

[0100]

[0101] In the above formula (17), p is the formation pressure in Pa; r is the distance from the wellbore in meters; p s This represents the initial formation pressure, expressed in Pa.

[0102] Furthermore, the boundary conditions for the mathematical model of oil-water two-phase flow can be shown in the following formula (18):

[0103]

[0104] In the above formula (18), t represents time, in seconds; t inj q represents the water injection time, measured in seconds (s). inj This refers to the water injection volume, measured in meters (m). 3 / s.

[0105] Step 102: Solve the mathematical model of the oil-water two-phase flow using the finite difference method to obtain the pressure changes and water saturation changes in each seepage zone.

[0106] Among them, the pressure change in each seepage zone can refer to the dynamic change law of pressure in each seepage zone, and the water saturation change in each seepage zone can refer to the dynamic change law of water saturation in each seepage zone.

[0107] In practical applications, to improve the accuracy and stability of the solution, the finite difference method can be used to solve the mathematical model of oil-water two-phase flow. This can include implicitly handling the pressure and water saturation terms using the finite difference method to solve the mathematical model. That is, during the solution process of the oil-water two-phase flow mathematical model using the finite difference method, the pressure and water saturation terms can be implicitly handled.

[0108] The solution process can be summarized as follows:

[0109] In the discretization process of the mathematical model for oil-water two-phase flow, based on IMPES, capillary pressure and conductivity coefficient are implicitly handled to increase the stability of the equations. After discretization, a shape factor F, which is only related to the mesh size, is introduced and defined as follows:

[0110]

[0111] In the above formula (19), T o is the oil phase conductivity, in kg / (Pa·s); F is the shape factor, dimensionless.

[0112] Furthermore, the oil phase governing equation can be obtained, as shown in the following formula (20):

[0113]

[0114] In the above formula (20), Q o V represents the oil phase mass flow rate, expressed in kg / s. M Pore ​​volume, in meters (m). 3 The superscripts represent time items corresponding to time steps n or n+1 respectively.

[0115] Using a similar method, the water phase control equation can be obtained, as shown in the following formula (21):

[0116]

[0117] In the above formula (21), T w Q is the conductivity of the aqueous phase, expressed in kg / (Pa·s). wThis represents the water phase mass flow rate, expressed in kg / s.

[0118] In the calculation, the nonlinear characteristics of the conduction coefficient in the spatial term caused by the function of saturation are treated, while viscosity is still treated explicitly.

[0119] Furthermore, in the above formula (20) It can be written as the following formula (22):

[0120]

[0121] Among them, T o For p, S w The function, in specific calculations, can be represented by T. n+1 In T n Expanding the neighborhood of into a Taylor series, then taking its first-order expansion and ignoring second-order minor quantities, yields the corresponding expression. The specific process is as follows:

[0122] T o With p, S w The functional relationship can be shown in the following formulas (23) and (24):

[0123]

[0124] In the above formula (23), T is the conductivity, and the unit is kg / (Pa·s).

[0125]

[0126] Based on the above formulas (23) and (24), we can obtain:

[0127]

[0128] Substituting the above formula (25) into the above formula (20), we get the following: It can be shown in the following formula (26):

[0129]

[0130] Because within a time step, δp, δS w Since the variables are very small, the second-order minor quantities can be ignored. Furthermore, the semi-implicit expression for the spatial difference term of the oil phase control equation in the three-phase flow state can be shown in the following formula (27):

[0131]

[0132] Similarly, the capillary pressure term in the above formula (21) can be written as the following formula (28):

[0133]

[0134] Substituting the above formula (28) into the above formula (21), we get the following: As shown in the following formula (29), the semi-implicit expression of the spatial difference term of the aqueous phase control equation can be expressed as follows:

[0135]

[0136] In the above formula (29),

[0137] In actual calculations, the right-hand sides of the oil phase governing equation and the water phase governing equation are completely consistent with the expansion of the IMPES method, that is:

[0138]

[0139] in,

[0140] In the above formula, C R V is the rock compressibility coefficient, with units of 1 / Pa; i The volume of the unit mesh obtained by partitioning, in meters. 3 .

[0141] Substituting equation (27) into equation (30) and equation (29) into equation (31), we can obtain the implicit difference expressions for the three-phase flow equations, as shown in equations (32) and (33) below:

[0142]

[0143] By combining formulas (32) and (33), the pressure per unit time (δp) and saturation (δS) can be calculated. o δS w The changes in pressure and saturation are analyzed. In this calculation, instead of solving for the pressure and saturation of each phase, the changes in the pressure and saturation fields per unit time, δp and δS, are determined. w Compared to the IMPES method, it has higher computational accuracy and better stability.

[0144] Therefore, we can obtain the following from formula (32):

[0145]

[0146] In the above formula (34), the subscript i±1 / 2 corresponds to the transfer capability between meshes, and the subscript i±1 corresponds to the inherent properties of the mesh.

[0147] Based on the upstream weight principle, all variables and coefficients with subscripts of i±1 / 2 are assigned to the corresponding nodes, and the above formula (34) can be reorganized as follows:

[0148]

[0149] in,

[0150]

[0151] Similarly, for formula (33), we can obtain:

[0152]

[0153] Furthermore, the above formula (36) can be rearranged as follows:

[0154] in:

[0155]

[0156]

[0157] In the above formula, α, β and γ correspond to the coefficients of the solution variables of the previous node, the current node and the next node, respectively. The subscripts i1 and i2 correspond to the coefficients of δp and δSw, respectively. The subscripts o and w correspond to the oil and water equations, respectively.

[0158] If we set N grid nodes, and each node can produce two equations similar to equations and , then we get a system of 2N equations. Combining these equations and writing them in matrix form, we have:

[0159] Au = G(38);

[0160] From the system of equations, we can deduce that in the above formula (38):

[0161]

[0162] u=(u1u2u3L u n ) T ;

[0163] G=(g1g2g3L g n ) T ;

[0164] in, u i =(δpδS) w ) T g i =(g o,i g w,i ) T .

[0165] α, β, and γ are second-order matrices, and matrix A is a block tridiagonal matrix that can be solved using the chasing method. Based on the obtained δp and δSw, the pressure field and saturation field at time t+1 can be calculated.

[0166] catch Figure 3 and Figure 4 In a specific embodiment, the model's basic parameters include an initial water saturation of 0.3, an initial formation pressure of 15 MPa, a bottomhole flowing pressure of 5 MPa, a matrix permeability of 0.3 mD, a fracture network permeability of 10 mD, a main fracture permeability of 1 D, a fracture half-length of 200 m, and a fracture network area extending 60 m perpendicular to the fracture half-length. The pressure field distribution and water saturation distribution at different times can be simulated and calculated based on the scheme provided in this application embodiment as follows: Figure 5 As shown.

[0167] Step 103: Based on the changes in pressure and water saturation in each seepage zone, determine whether there is a seepage-replacement effect.

[0168] In this embodiment of the application, step 103 may specifically include: if the production pressure difference between the first region and the second region is greater than the capillary pressure difference between the first region and the second region, then there is no percolation and replacement effect; if the production pressure difference between the first region and the second region is less than the capillary pressure difference between the first region and the second region, then there is a percolation and replacement effect; the distance from the first region to the wellbore is less than the distance from the second region to the wellbore, and the water saturation of the first region is greater than the water saturation of the second region.

[0169] The production pressure difference between the first and second regions can be obtained by subtracting the pressure of the first region from the pressure of the second region, and the capillary pressure difference between the first and second regions can be obtained by subtracting the capillary pressure of the first region from the capillary pressure of the second region.

[0170] like Figure 6 As shown, the blue and red grids represent two adjacent grid cells during the development of tight oil reservoirs. The water saturation and pressure of the blue grid are S0 and S0, respectively. w1 P1, the water saturation and pressure of the red grid are respectively S w2 P2; where the blue grid is closer to the wellbore, therefore P2 > P1, meaning the pressure displacement direction is from right to left. Due to the large injection of fracturing fluid, the water saturation in the near-wellbore zone increases, i.e., S w1 >S w2 Furthermore, the capillary pressure P of the blue grid can be obtained. c (S w1 < Capillary pressure P of the red grid c(S w2 This means that there exists a P. c (S w2 )-P c (S w1 The force of the pressure difference (ΔP) causes the water saturation field to tend towards equilibrium. Therefore, when the production pressure difference ΔP = P2 - P1 is large, specifically P2 - P1 > P... c (S w2 )-P c (S w1 If the capillary force acts in the same direction as the pressure displacement, it means that the capillary force is acting in the same direction as the pressure displacement, and there is no percolation or displacement effect. If the production pressure difference ΔP = P2 - P1 is small, specifically P2 - P1 < P c (S w2 )-P c (S w1 This means that the direction of capillary force is opposite to the direction of pressure differential displacement. In this case, the capillary force's adsorption-displacement effect is dominant, i.e., adsorption-displacement exists. Under this adsorption-displacement effect, the initial fracturing fluid will penetrate into the formation, displacing formation fluids to the near-wellbore zone, thereby achieving the development effect of increasing oil production and reducing water. Furthermore, the adsorption-displacement effect is greatly affected by the ability of fracturing fluid in the near-wellbore zone to penetrate deeper into the formation, i.e., it is greatly influenced by capillary force, water saturation, and production pressure differential.

[0171] In the development of tight oil reservoirs, due to the hydraulic fracturing development mode, the water saturation in the near-wellbore zone is much higher than the initial formation conditions, meaning that the direction of percolation is from the near-wellbore zone to the deeper formation. Under the action of capillary force, as the fracturing fluid penetrates into the deeper formation, it displaces the bottom fluid from the deeper formation to the near-wellbore zone to maintain pressure balance. Therefore, the mechanism of percolation and displacement is mainly through capillary force allowing the fracturing fluid in the near-wellbore zone to penetrate into the deeper formation and displace an equal volume of formation fluid. In short, percolation and displacement occurs because the difference in water saturation at the interface allows the wetting phase fluid to penetrate into the reservoir through capillary force, displacing an equal volume of formation fluid. Excluding the amount displaced by pressure differential, the amount of formation fluid displaced solely by capillary force is the percolation and displacement amount. The proportion of this to the total formation flow rate is the contribution rate of percolation and displacement to the production of tight oil reservoirs.

[0172] By analyzing the pressure and water saturation variations within each seepage zone, it's possible to determine the presence of adsorption-displacement effects. This can also be understood as assessing the differences in pressure and water saturation fields between seepage zones to determine the existence of adsorption-displacement effects. In addition to determining the presence of adsorption-displacement effects, in practical applications, the differences in pressure and water saturation fields between seepage zones can also be used to determine the mechanism of pressure differential displacement. Therefore, when determining the contribution of adsorption-displacement effects to the development and production of tight oil reservoirs, the mechanism of pressure differential displacement can be further considered. This allows for a more accurate calculation of the contribution of adsorption-displacement effects to the development and production of tight oil reservoirs.

[0173] Step 104: If there is a percolation and displacement effect, the contribution rate of the percolation and displacement effect to the development and production of tight oil reservoirs is determined based on the steady-state radial flow mathematical model; if there is no percolation and displacement effect, the contribution rate of the percolation and displacement effect to the development and production of tight oil reservoirs is determined to be zero.

[0174] In this embodiment of the application, determining the contribution rate of percolation and displacement to the development production of tight oil reservoirs based on a steady-state radial seepage mathematical model may include steps one, two, and three, as follows:

[0175] Step 1: Establish a steady-state radial seepage mathematical model for the target porous media unit.

[0176] The target porous medium unit can be any porous medium unit.

[0177] In practical implementation, a steady-state radial seepage mathematical model can be established to determine the contribution of differential pressure displacement and percolation to the total formation flow rate at a given instant in any porous media unit. During the depletion-type development of a single well in a tight oil reservoir, differential pressure displacement causes formation fluids, whether wetting phases or formation fluids, to flow into the wellbore.

[0178] In this embodiment of the application, a steady-state radial seepage mathematical model can be established based on the following formula (39):

[0179]

[0180] Among them, at the inner boundary: p c (S w,in ) = p o,in -p w,in At the outer boundary:

[0181] In the above formula, G is the starting pressure gradient, with units of Pa / m; This represents the average water saturation level within the dynamic sweep range; the subscript "in" indicates the inner boundary condition, and the subscript "out" indicates the outer boundary condition. For example, P o,inP is the oil phase pressure at the inner boundary. o,out This represents the oil phase pressure at the outer boundary, and so on.

[0182] Step two: Solve the steady-state radial seepage mathematical model to obtain the oil production per unit time.

[0183] By solving the above formula (39), the flow rate into the inner boundary of the porous medium unit can be obtained, as shown in the following formulas (40) and (41):

[0184]

[0185]

[0186] In the above formula (40), Q o This represents the oil production per unit time under pressure displacement, expressed in m³. 3 / s; h is the formation thickness in meters.

[0187] In the above formula (41), Q w This refers to the water production per unit time under pressure displacement, expressed in cubic meters per second (m³). 3 / s.

[0188] Based on the mechanism of percolation and displacement, the injected water penetrates deep into the formation. To maintain stable formation pressure, it replaces an equal volume of oil in the near-wellbore zone. Therefore, the oil production contributed by percolation and displacement is equal to the volume of water that penetrates deep into the formation under the capillary force difference.

[0189]

[0190] Among them, Q o,im This represents the oil production per unit time under the action of percolation and displacement, expressed in m³. 3 / s.

[0191] Step 3: Based on the oil production, obtain the contribution rate of percolation and displacement to the development and production of tight oil reservoirs.

[0192] In this embodiment, the contribution rate of percolation and displacement to the development and production of tight oil reservoirs can be obtained when the oil-water two phases reach stability. Where γ is the osmotic displacement contribution rate, which is dimensionless. Substituting formulas (42) and (40) into this contribution rate calculation formula, we can obtain:

[0193]

[0194] It is understood that the quantitative characterization method for percolation and displacement provided in the above embodiments of this application includes: establishing a mathematical model of oil-water two-phase flow corresponding to the target flow field structure based on capillary action; solving the mathematical model of oil-water two-phase flow using the finite difference method to obtain the pressure changes and water saturation changes in each seepage zone; determining whether percolation and displacement exist based on the pressure changes and water saturation changes in each seepage zone; if percolation and displacement exist, determining the contribution rate of percolation and displacement to the development and production of tight oil reservoirs based on the steady-state radial flow mathematical model; if percolation and displacement do not exist, determining that the contribution rate of percolation and displacement to the development and production of tight oil reservoirs is zero. Since the scheme provided in the embodiments of this application can quantitatively characterize percolation and displacement and obtain the contribution rate of percolation and displacement to the development and production of tight oil reservoirs, it can provide more accurate guidance for actual production schemes, which is of great significance for subsequent efficient development and improving the recovery rate of tight oil reservoirs.

[0195] In practical applications, after step 104, the quantitative characterization method for osmotic displacement provided in this application embodiment may further include step ①, as follows:

[0196] Step ①: Determine the contribution rate of percolation and displacement to the development and production of tight oil reservoirs under different water saturation conditions as a function of production pressure differential.

[0197] In practice, the contribution rate of the permeation and replacement effect to the development output of tight oil reservoirs under different water saturation conditions can be plotted based on the above formula (43) to form a graph of the contribution rate of the permeation and replacement effect.

[0198] In a specific embodiment of this application, the contribution rate chart of percolation and displacement can be as follows: Figure 7 As shown in the contribution rate chart, when the production pressure differential is larger, the displacement effect dominates, leading to a decrease in the contribution rate of the percolation and replacement effect. When the water saturation is low, the capillary pressure effect is significant. If the capillary force can overcome the production pressure differential, the contribution rate of the percolation and replacement effect to tight oil development is more significant.

[0199] In practical applications, based on step ① above, the quantitative characterization method for osmotic displacement provided in this application embodiment may further include step ②, as follows:

[0200] Step ②: Determine how the contribution of the percolation and displacement effect in each seepage zone to the development production of tight oil reservoirs changes with the development time.

[0201] That is, based on the water saturation and production pressure difference at a certain moment during development, the contribution rate of the permeation and replacement effect at that moment is read from the contribution rate chart obtained in step ①. Then, based on the contribution rate of the permeation and replacement effect at each moment during development, the change of the contribution rate of the permeation and replacement effect to the development production of tight oil reservoirs with the development time can be obtained.

[0202] In practical implementation, the contribution rate of percolation and displacement to tight reservoir development production in each seepage zone can be obtained as a function of development time, based on the dynamic evolution law of the flow field and the scheme provided in the above embodiments of this application. The contribution of percolation and displacement to production capacity is mainly reflected in the fracture network zone and the matrix zone. Since the scale of the main fracture zone is relatively large, its capillary force effect can be ignored.

[0203] In a specific embodiment of this application, based on the dynamic changes in multi-regional flow field, water saturation, and pressure during the development of tight oil reservoirs, the variation law of the contribution rate of permeation and displacement at different times can be obtained as follows: Figure 8 As shown in the figure, simulation results indicate that as production development progresses, the dynamic supply boundary gradually expands, and the production pressure differential in the stitched mesh zone decreases significantly, leading to a gradual increase in the contribution rate of the percolation-displacement effect. When development reaches 2000 days, the contribution rate of the percolation-displacement effect to the yield can increase from the initial 0.1% to 2%. When it extends to the matrix zone, although the capillary pressure in the matrix zone is stronger, the production pressure differential in the matrix zone shows a gradual increasing trend due to the influence of pressure diffusion, which in turn leads to a gradual decrease in the percolation-displacement effect.

[0204] Based on the same inventive concept, such as Figure 9 As shown, Figure 9 This schematically illustrates a structural block diagram of a quantitative characterization device for osmosis-displacement according to an embodiment of the present application. In one embodiment, a quantitative characterization device 200 for osmosis-displacement is provided, including a model building module 210, a solution module 220, a judgment module 230, and a contribution rate calculation module 240, wherein:

[0205] Model building module 210 is used to establish a mathematical model of oil-water two-phase flow based on capillary action to the target flow field structure.

[0206] The solver module 220 is used to solve the mathematical model of the oil-water two-phase flow using the finite difference method to obtain the pressure changes and water saturation changes in each seepage zone.

[0207] The judgment module 230 is used to determine whether there is a seepage replacement effect based on the changes in pressure and water saturation in each seepage zone.

[0208] The contribution rate calculation module 240 is used to determine the contribution rate of the seepage and replacement effect to the development and production of tight oil reservoirs based on the steady-state radial seepage mathematical model if seepage and replacement effect exists; if seepage and replacement effect does not exist, the contribution rate of seepage and replacement effect to the development and production of tight oil reservoirs is determined to be zero.

[0209] In one embodiment, the model building module 210 is used to establish a mathematical model of oil-water two-phase flow corresponding to the target flow field structure based on the mass conservation equation, the relative permeability correlation equation and the capillary force correlation equation.

[0210] In one embodiment, the capillary force-related equation is shown in the following formula:

[0211]

[0212] Where, p c Capillary pressure, unit: Pa; S w σ is the water saturation; J is the J function; θ is the wetting angle in °; σ is the interfacial tension in N / m; φ is the porosity of the rock; k is the permeability of the rock in m³. 2 a and b are constant terms.

[0213] In one embodiment, the determination module 230 is used to determine that there is no percolation and displacement effect if the production pressure difference between the first region and the second region is greater than the capillary pressure difference between the first region and the second region.

[0214] If the production pressure difference between the first region and the second region is less than the capillary pressure difference between the first region and the second region, it is determined that there is a percolation and displacement effect.

[0215] The distance from the first region to the wellbore is less than the distance from the second region to the wellbore, and the water saturation of the first region is greater than that of the second region; the production pressure difference between the first region and the second region is obtained by subtracting the pressure of the first region from the pressure of the second region, and the capillary pressure difference between the first region and the second region is obtained by subtracting the capillary pressure of the first region from the capillary pressure of the second region.

[0216] In one embodiment, the contribution rate calculation module 240 is used to establish a steady-state radial seepage mathematical model for the target porous media unit.

[0217] The steady-state radial seepage mathematical model is solved to obtain the oil production per unit time;

[0218] Based on the oil production, the contribution rate of percolation and displacement to the development and production of tight oil reservoirs was obtained.

[0219] In one embodiment, the oil production includes the oil production corresponding to pressure displacement and the oil production corresponding to percolation and displacement. The contribution rate calculation module 240 is then used to obtain the contribution rate of percolation and displacement to the development production of tight oil reservoirs based on the following formula:

[0220]

[0221] Wherein, γ represents the contribution rate of percolation and displacement to the development and production of tight oil reservoirs; Q o This represents the oil production corresponding to pressure differential displacement, in cubic meters (m³). 3 / s;Q o,im This represents the oil production corresponding to the percolation and displacement process, in m³. 3 / s;

[0222] Oil production Q corresponding to percolation displacement o,im Based on the following formula:

[0223]

[0224] Where k is the permeability of the rock, in meters. 2 ;k rw The relative permeability of the aqueous phase; ρ represents the average water saturation within the dynamic sweep range; h represents the formation thickness in meters; p c Capillary pressure, unit: Pa; S w,in The water saturation at the inner boundary; μ w The viscosity of the aqueous phase is expressed in Pa·s; r out r is the distance from the outer boundary to the wellbore, in meters (m). in This represents the distance from the inner boundary to the wellbore, in meters (m).

[0225] In one embodiment, the contribution rate calculation module 240 is also used to determine how the contribution rate of the seepage and displacement effect in each seepage zone to the development production of tight oil reservoirs changes with the development time.

[0226] The quantitative characterization device for osmosis and displacement includes a processor and a memory. The model building module 210, the solution module 220, the judgment module 230, and the contribution rate calculation module 240 are all stored in the memory as program units. The processor executes the program modules stored in the memory to implement the corresponding functions.

[0227] The processor contains a core, which retrieves the corresponding program unit from memory. One or more cores can be configured, and by adjusting the core parameters, fast and efficient modeling and computation can be achieved at the entire chip scale.

[0228] The memory may include non-permanent memory in computer-readable media, such as random access memory (RAM) and / or non-volatile memory, such as read-only memory (ROM) or flash RAM, and the memory includes at least one memory chip.

[0229] This application provides a machine-readable storage medium storing a program that, when executed by a processor, implements the above-described method for quantitative characterization of osmosis and displacement.

[0230] In one embodiment, a computer device is provided, which may be a terminal, and its internal structure diagram may be as follows: Figure 10 As shown in the figure, the computer device includes a processor A01, a network interface A02, a display screen A04, an input device A05, and a memory (not shown) connected via a system bus. The processor A01 provides computing and control capabilities. The memory includes internal memory A03 and a non-volatile storage medium A06. The non-volatile storage medium A06 stores an operating system B01 and a computer program B02. The internal memory A03 provides an environment for the operation of the operating system B01 and the computer program B02 stored in the non-volatile storage medium A06. The network interface A02 is used for communication with external terminals via a network connection. When the computer program is executed by the processor A01, it implements a method for quantitative characterization of osmotic displacement. The display screen A04 can be a liquid crystal display or an e-ink display. The input device A05 can be a touch layer covering the display screen, buttons, a trackball, or a touchpad mounted on the computer device casing, or an external keyboard, touchpad, or mouse.

[0231] Those skilled in the art will understand that Figure 10 The structure shown is merely a block diagram of a portion of the structure related to the present application and does not constitute a limitation on the computer device to which the present application is applied. Specific computer devices may include more or fewer components than those shown in the figure, or combine certain components, or have different component arrangements.

[0232] In one embodiment, the quantitative characterization device for osmosis and displacement provided in this application can be implemented as a computer program, which can be used in, for example... Figure 10 The computer device shown runs on this system. The computer device's memory can store the various program modules that make up the intelligent scheduling device for this construction task, for example... Figure 9The model building module 210, solution module 220, judgment module 230, and contribution rate calculation module 240 are shown. The computer program composed of these modules enables the processor to execute the steps in the quantitative characterization methods for osmosis-displacement effects described in the various embodiments of this application.

[0233] Figure 10 The computer device shown can be used as follows Figure 9 The model building module 210, solution module 220, judgment module 230 and contribution rate calculation module 240 in the quantitative characterization device for osmosis and displacement shown are executed by the following method.

[0234] This application provides a device, which includes a processor, a memory, and a program stored in the memory and executable on the processor. When the processor executes the program, it performs the following steps:

[0235] A mathematical model of oil-water two-phase flow based on capillary action is established for the target flow field structure.

[0236] The mathematical model of the oil-water two-phase flow was solved using the finite difference method to obtain the pressure changes and water saturation changes in each flow zone.

[0237] Based on the changes in pressure and water saturation in each seepage zone, determine whether there is a seepage-replacement effect.

[0238] If percolation and displacement occur, the contribution rate of percolation and displacement to the development and production of tight oil reservoirs is determined based on the steady-state radial flow mathematical model; if percolation and displacement do not occur, the contribution rate of percolation and displacement to the development and production of tight oil reservoirs is determined to be zero.

[0239] In one embodiment, establishing the oil-water two-phase seepage mathematical model corresponding to the target flow field structure based on capillary action includes:

[0240] A mathematical model of oil-water two-phase flow is established based on the mass conservation equation, the relative permeability correlation equation, and the capillary force correlation equation.

[0241] In one embodiment, the capillary force-related equation is shown in the following formula:

[0242]

[0243] Where, p c Capillary pressure, unit: Pa; S w σ is the water saturation; J is the J function; θ is the wetting angle in °; σ is the interfacial tension in N / m; φ is the porosity of the rock; k is the permeability of the rock in m³. 2a and b are constant terms.

[0244] In one embodiment, determining whether percolation or displacement occurs based on changes in pressure and water saturation within each seepage zone includes:

[0245] If the production pressure difference between the first region and the second region is greater than the capillary pressure difference between the first region and the second region, then there is no percolation displacement effect;

[0246] If the production pressure difference between the first region and the second region is less than the capillary pressure difference between the first region and the second region, then there is a percolation and displacement effect.

[0247] The distance from the first region to the wellbore is less than the distance from the second region to the wellbore, and the water saturation of the first region is greater than that of the second region; the production pressure difference between the first region and the second region is obtained by subtracting the pressure of the first region from the pressure of the second region, and the capillary pressure difference between the first region and the second region is obtained by subtracting the capillary pressure of the first region from the capillary pressure of the second region.

[0248] In one embodiment, determining the contribution rate of percolation and displacement to tight reservoir development production based on a steady-state radial flow mathematical model includes:

[0249] A steady-state radial seepage mathematical model was established for the target porous media unit;

[0250] The steady-state radial seepage mathematical model is solved to obtain the oil production per unit time;

[0251] Based on the oil production, the contribution rate of percolation and displacement to the development and production of tight oil reservoirs was obtained.

[0252] In one embodiment, the oil production includes the oil production corresponding to pressure displacement and the oil production corresponding to percolation and displacement. The contribution rate of percolation and displacement to the development production of tight oil reservoirs is obtained based on the following formula:

[0253]

[0254] Wherein, γ represents the contribution rate of percolation and displacement to the development and production of tight oil reservoirs; Q o This represents the oil production corresponding to pressure differential displacement, in cubic meters (m³). 3 / s;Q o,im This represents the oil production corresponding to the percolation and displacement process, in m³. 3 / s;

[0255] Oil production Q corresponding to percolation displacement o,im Based on the following formula:

[0256]

[0257] Where k is the permeability of the rock, in meters. 2 ;k rw The relative permeability of the aqueous phase; ρ represents the average water saturation within the dynamic sweep range; h represents the formation thickness in meters; p c Capillary pressure, unit: Pa; S w,in The water saturation at the inner boundary; μ w The viscosity of the aqueous phase is expressed in Pa·s; r out r is the distance from the outer boundary to the wellbore, in meters (m). in This represents the distance from the inner boundary to the wellbore, in meters (m).

[0258] In one embodiment, the method further includes:

[0259] To determine how the contribution of percolation and displacement in each seepage zone to the production of tight oil reservoirs varies with the development time.

[0260] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0261] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0262] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxesFigure 1 The function specified in one or more boxes.

[0263] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0264] In a typical configuration, a computing device includes one or more processors (CPU), input / output interfaces, network interfaces, and memory.

[0265] Memory may include non-persistent memory in computer-readable media, such as random access memory (RAM) and / or non-volatile memory, such as read-only memory (ROM) or flash RAM. Memory is an example of computer-readable media.

[0266] Computer-readable media include both permanent and non-permanent, removable and non-removable media, which can store information using any method or technology. Information can be computer-readable instructions, data structures, modules of programs, or other data. Examples of computer storage media include, but are not limited to, phase-change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technologies, CD-ROM, digital versatile optical disc (DVD) or other optical storage, magnetic tape, magnetic magnetic disk storage or other magnetic storage devices, or any other non-transferable medium that can be used to store information accessible by a computing device. As defined herein, computer-readable media does not include transient computer-readable media, such as modulated data signals and carrier waves.

[0267] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0268] The above are merely embodiments of this application and are not intended to limit the scope of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of the claims of this application.

Claims

1. A method for quantitative characterizing osmotic displacement, characterized in that, include: A mathematical model of oil-water two-phase flow based on capillary action is established for the target flow field structure. The mathematical model of the oil-water two-phase flow was solved using the finite difference method to obtain the pressure changes and water saturation changes in each flow zone. Based on the changes in pressure and water saturation in each seepage zone, determine whether there is a seepage-replacement effect. If percolation and displacement occur, the contribution rate of percolation and displacement to the development and production of tight oil reservoirs is determined based on the steady-state radial flow mathematical model; if percolation and displacement do not occur, the contribution rate of percolation and displacement to the development and production of tight oil reservoirs is determined to be zero.

2. The method for quantitative characterization of osmotic displacement according to claim 1, characterized in that, The mathematical model for oil-water two-phase flow based on capillary action to establish the target flow field structure includes: A mathematical model of oil-water two-phase flow is established based on the mass conservation equation, the relative permeability correlation equation, and the capillary force correlation equation.

3. The quantitative characterization method for osmotic displacement according to claim 2, characterized in that, The capillary force-related equation is shown in the following formula: Where, p c Capillary pressure, unit: Pa; S w σ is the water saturation; J is the J function; θ is the wetting angle in °; σ is the interfacial tension in N / m; φ is the porosity of the rock; k is the permeability of the rock in m³. 2 a and b are constant terms.

4. The method for quantitative characterization of osmotic displacement according to claim 1, characterized in that, The determination of whether percolation and displacement occur based on changes in pressure and water saturation within each seepage zone includes: If the production pressure difference between the first region and the second region is greater than the capillary pressure difference between the first region and the second region, then there is no percolation displacement effect; If the production pressure difference between the first region and the second region is less than the capillary pressure difference between the first region and the second region, then there is a percolation and displacement effect. The distance from the first region to the wellbore is less than the distance from the second region to the wellbore, and the water saturation of the first region is greater than that of the second region; the production pressure difference between the first region and the second region is obtained by subtracting the pressure of the first region from the pressure of the second region, and the capillary pressure difference between the first region and the second region is obtained by subtracting the capillary pressure of the first region from the capillary pressure of the second region.

5. The method for quantitative characterization of osmotic displacement according to claim 1, characterized in that, The determination of the contribution rate of percolation and displacement to the development and production of tight oil reservoirs based on the steady-state radial seepage mathematical model includes: A steady-state radial seepage mathematical model was established for the target porous media unit; The steady-state radial seepage mathematical model is solved to obtain the oil production per unit time; Based on the oil production, the contribution rate of percolation and displacement to the development and production of tight oil reservoirs was obtained.

6. The method for quantitative characterization of osmotic displacement according to claim 5, characterized in that, The oil production includes the oil production corresponding to pressure displacement and the oil production corresponding to percolation and displacement. The contribution rate of percolation and displacement to the development production of tight oil reservoirs can be obtained based on the following formula: Wherein, γ represents the contribution rate of percolation and displacement to the development and production of tight oil reservoirs; Q o This represents the oil production corresponding to pressure differential displacement, in cubic meters (m³). 3 / s;Q o,im This represents the oil production corresponding to the percolation and displacement process, in m³. 3 / s; Oil production Q corresponding to percolation displacement o,im Based on the following formula: Where k is the permeability of the rock, in meters. 2 ;k rw S represents the relative permeability of the aqueous phase. w ρ represents the average water saturation within the dynamic sweep range; h represents the formation thickness in meters; p c Capillary pressure, unit: Pa; S w,in The water saturation at the inner boundary; μ w The viscosity of the aqueous phase is expressed in Pa·s; r out r is the distance from the outer boundary to the wellbore, in meters (m). in This represents the distance from the inner boundary to the wellbore, in meters (m).

7. The method for quantitative characterization of osmotic displacement according to claim 1, characterized in that, The method further includes: To determine how the contribution of percolation and displacement in each seepage zone to the production of tight oil reservoirs varies with the development time.

8. A device for quantitative characterizing osmotic displacement, characterized in that, include: The model building module is used to establish a mathematical model of oil-water two-phase flow based on capillary action to create a target flow field structure. The solution module is used to solve the mathematical model of the oil-water two-phase flow using the finite difference method, and to obtain the pressure changes and water saturation changes in each seepage zone. The judgment module is used to determine whether there is a seepage replacement effect based on the changes in pressure and water saturation in each seepage zone. The contribution rate calculation module is used to determine the contribution rate of the seepage and replacement effect to the development and production of tight oil reservoirs based on the steady-state radial seepage mathematical model if seepage and replacement effect exists; if seepage and replacement effect does not exist, the contribution rate of seepage and replacement effect to the development and production of tight oil reservoirs is determined to be zero.

9. A processor, characterized in that, It is configured to perform the quantitative characterization method of osmotic displacement according to any one of claims 1 to 7.

10. A machine-readable storage medium storing instructions thereon, characterized in that, When executed by a processor, this instruction causes the processor to be configured to perform the quantitative characterization method of osmotic displacement according to any one of claims 1 to 7.

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