Method, device and equipment for determining oil extraction contribution degree of unconventional oil reservoir and medium

Abstract

The embodiment of the invention provides an unconventional oil reservoir oil extraction contribution degree determination method and device, equipment and a medium. The method comprises the steps that the relation between the saturation degree of wet-phase fluid and capillary pressure in an oil reservoir is determined according to a plurality of reference capillary pressure curves; performing simulation analysis on the crack propagation direction and the seepage pressure in the oil reservoir volume fracturing process, and determining a three-dimensional propagation rule of the crack and artificial crack parameters; performing coupling processing on the three-dimensional fracture model and the matrix attribute model to obtain an oil reservoir geological engineering integrated model; establishing a numerical simulation model according to the relationship between the wet-phase fluid saturation and the capillary pressure and the reservoir geological engineering integrated model; performing numerical simulation on the oil reservoir development process through the numerical simulation model to obtain data simulation results of the oil reservoir in different development stages; the oil production contribution degrees of displacement and imbibition in different development stages of the oil reservoir are determined according to a data simulation result, and a theoretical basis and technical support are provided for oil reservoir exploitation.

Description

Technical Field

[0001] The present application relates to the field of oil production technology, and in particular to a method, device, equipment and medium for determining the contribution degree of oil production in unconventional oil reservoirs. Background Art

[0002] For oil reservoirs with extremely low permeability, it is difficult to achieve effective displacement due to the difficulty of water injection development. Therefore, the current main method is to use large-scale volume fracturing technology of horizontal wells to form a large number of artificial fractures, and then combine it with water injection huff-and-puff technology to develop low permeability oil reservoirs.

[0003] After the production area has been fracturing, when water injection is used for oil production, the spontaneous imbibition of capillary pressure is an important mechanism in the oil production process. However, the imbibition process is not only affected by the capillary pressure, but also by the displacement pressure difference, making the imbibition mechanism more complicated. In addition, in the oil reservoir after fracturing, the injected water is easy to channel along the cracks formed by fracturing, resulting in low utilization of crude oil inside the matrix.

[0004] Existing research on imbibition oil recovery is mostly focused on the core scale, through indirect and qualitative analysis of crude oil mobility, imbibition dynamics and its influencing factors, but lacks a method to quantitatively determine the contribution of displacement and imbibition to reservoir recovery at a macro scale. Summary of the invention

[0005] The embodiments of the present application provide a method, device, equipment and medium for determining the contribution degree of unconventional oil reservoir oil production, so as to solve the problem that the prior art lacks a quantitative analysis process for the contribution degree of displacement and imbibition to the recovery rate during the unconventional oil reservoir exploitation process.

[0006] In a first aspect, the present application provides a method for determining the contribution degree of oil production in an unconventional oil reservoir, comprising:

[0007] Obtaining reference capillary pressure curves of different types of oil reservoirs, and determining a relationship characterization model between the saturation of the wetting phase fluid and the capillary pressure in the oil reservoir according to a plurality of reference capillary pressure curves;

[0008] Simulate and analyze the crack expansion direction and seepage pressure during the volume fracturing process of the oil reservoir, determine the three-dimensional expansion law of the volume fracturing cracks in the oil reservoir, and obtain artificial fracture parameters based on the three-dimensional expansion law;

[0009] Establishing a three-dimensional fracture model according to the artificial fracture parameters, coupling the three-dimensional fracture model with a matrix property model to obtain an integrated reservoir geology and engineering model;

[0010] Establishing a numerical simulation model based on the relationship representation model and the reservoir geology and engineering integration model;

[0011] The numerical simulation model is used to numerically simulate the oil reservoir development process to obtain data simulation results of the oil reservoir at different development stages;

[0012] The plurality of data simulation results are analyzed and processed to obtain analysis results, and the contribution of displacement and imbibition to oil production at different development stages of the oil reservoir is determined according to the analysis results.

[0013] Optionally, the simulation analysis of the crack expansion direction and seepage pressure during the volume fracturing process of the oil reservoir to determine the three-dimensional expansion law of the volume fracturing cracks in the oil reservoir formation includes:

[0014] Obtain actual fracturing data information;

[0015] Establish a stress field-seepage coupling mathematical model for the target study area, and simulate and analyze the fracture extension direction and seepage pressure based on the extended finite element method to obtain simulation analysis results;

[0016] The three-dimensional expansion law of volume fracturing cracks in the oil reservoir is determined based on the actual fracturing data information and the simulation analysis results.

[0017] Optionally, a three-dimensional fracture model is established according to the artificial fracture parameters, and the three-dimensional fracture model is coupled with a matrix property model to obtain an integrated reservoir geology and engineering model, including:

[0018] constructing a matrix property model according to matrix property parameters;

[0019] generating a fracture attribute model based on the artificial fracture parameters and the natural fracture parameters;

[0020] The fracture attribute model and the matrix attribute model are coupled to obtain an integrated reservoir geology and engineering model.

[0021] Optionally, a numerical simulation model is established based on the relationship representation model and the reservoir geology-engineering integrated model, including:

[0022] Modifying the grid properties of the fracture-controlled transformation area in the reservoir geology-engineering integrated model by using a local grid encryption method and combining the artificial fracture parameters;

[0023] A numerical simulation model is established based on the relationship representation model and the reservoir geology and engineering integrated model after grid attribute correction.

[0024] Optionally, the numerical simulation model is used to perform numerical simulation on the oil reservoir development process to obtain data simulation results of the oil reservoir at different development stages, including:

[0025] inputting basic parameters of the reservoir development process into the numerical simulation model;

[0026] Outputting pressure field diagrams and saturation field diagrams at different development stages through the numerical simulation model;

[0027] The pressure field map and the saturation field map are taken as the data simulation results.

[0028] Optionally, a plurality of the data simulation results are analyzed and processed to obtain analysis results, and the contribution of displacement and imbibition to oil recovery at different development stages of the oil reservoir is determined according to the analysis results, including:

[0029] Obtaining a displacement pressure difference according to the pressure field diagram;

[0030] According to the relative magnitude of the displacement pressure difference and the capillary pressure, the target research area is divided into a displacement-dominated area, a displacement-imbibition synergistic area and an imbibition-dominated area;

[0031] Determine the contribution of displacement dominance, displacement-imbibition synergy and imbibition dominance to oil recovery in reservoirs at different development stages.

[0032] Optionally, the method further includes:

[0033] Classify and evaluate the pore structure distribution of the oil reservoir according to the porosity and permeability of the oil reservoir to obtain an evaluation result;

[0034] According to the pore structure classification evaluation results of the oil reservoir, a displacement pressure difference-permeability map of the oil reservoir is constructed;

[0035] The influence of displacement dominance, displacement-imbibition synergy and imbibition dominance on the recovery factor are determined according to the displacement pressure difference-permeability diagram.

[0036] In a second aspect, the present application provides a device for determining the contribution degree of oil production in an unconventional oil reservoir, comprising:

[0037] An acquisition module, used to obtain reference capillary pressure curves of different types of oil reservoirs;

[0038] A determination module, used for determining a relationship characterization model between the saturation of the wet phase fluid and the capillary pressure in the reservoir according to a plurality of reference capillary pressure curves;

[0039] A processing module is used to simulate and analyze the crack expansion direction and seepage pressure during the volume fracturing process of the oil reservoir, determine the three-dimensional expansion law of the volume fracturing cracks of the oil reservoir, and obtain artificial fracture parameters according to the three-dimensional expansion law;

[0040] Establishing a three-dimensional fracture model according to the artificial fracture parameters, coupling the three-dimensional fracture model with a matrix property model to obtain an integrated reservoir geology and engineering model;

[0041] Establishing a numerical simulation model based on the relationship representation model and the reservoir geology and engineering integration model;

[0042] The numerical simulation model is used to numerically simulate the oil reservoir development process to obtain data simulation results of the oil reservoir at different development stages;

[0043] The plurality of data simulation results are analyzed and processed to obtain analysis results, and the contribution of displacement and imbibition to oil production at different development stages of the oil reservoir is determined according to the analysis results.

[0044] Optionally, the acquisition module is also used to acquire actual fracturing data information;

[0045] The processing module is also used to establish a stress field-seepage coupling mathematical model of the target study area, and simulate and analyze the fracture extension direction and seepage pressure based on the extended finite element method to obtain simulation analysis results;

[0046] The determination module is also used to determine the three-dimensional expansion law of volume fracturing cracks in the oil reservoir according to the actual fracturing data information and the simulation analysis results.

[0047] Optionally, the processing module is further used to construct a matrix property model according to the matrix property parameters;

[0048] generating a fracture attribute model based on the artificial fracture parameters and the natural fracture parameters;

[0049] The fracture attribute model and the matrix attribute model are coupled to obtain an integrated reservoir geology and engineering model.

[0050] Optionally, the processing module is further used to modify the grid properties of the fracture-controlled transformation area in the reservoir geology-engineering integrated model by using a local grid encryption method and combining the artificial fracture parameters;

[0051] A numerical simulation model is established based on the relationship representation model and the reservoir geology and engineering integrated model after grid attribute correction.

[0052] Optionally, the processing module is further used to input basic parameters of the reservoir development process into the numerical simulation model;

[0053] Outputting pressure field diagrams and saturation field diagrams at different development stages through the numerical simulation model;

[0054] The pressure field map and the saturation field map are taken as the data simulation results.

[0055] Optionally, the processing module is further used to obtain a displacement pressure difference according to the pressure field map;

[0056] According to the relative magnitude of the displacement pressure difference and the capillary pressure, the target research area is divided into a displacement-dominated area, a displacement-imbibition synergistic area and an imbibition-dominated area;

[0057] The determination module is also used to determine the contribution of displacement dominance, displacement-imbibition synergy and imbibition dominance to oil recovery in oil reservoirs at different development stages.

[0058] Optionally, the processing module is further used to classify and evaluate the pore structure distribution of the oil reservoir according to the porosity and permeability of the oil reservoir to obtain an evaluation result;

[0059] According to the pore structure classification evaluation results of the oil reservoir, a displacement pressure difference-permeability map of the oil reservoir is constructed;

[0060] The determination module is also used to determine the influence of displacement dominance, displacement-imbibition synergy and imbibition dominance on the recovery factor according to the displacement pressure difference-permeability chart.

[0061] In a third aspect, the present application provides a device for determining the contribution degree of oil production in unconventional oil reservoirs, comprising:

[0062] Memory;

[0063] processor;

[0064] Wherein, the memory stores computer-executable instructions;

[0065] The processor executes the computer-executable instructions stored in the memory to implement the method for determining the degree of oil recovery contribution of unconventional oil reservoirs as described in the first aspect and various possible implementations of the first aspect.

[0066] In a fourth aspect, the present application provides a computer storage medium having a computer program stored thereon, wherein the computer program is executed by a processor to implement the method for determining the degree of oil recovery contribution of unconventional oil reservoirs as described in the first aspect and various possible implementations of the first aspect.

[0067] The present application provides a method, device, equipment and medium for determining the contribution of unconventional oil reservoirs to oil production. The method includes: determining the relationship between the wet phase fluid saturation and the capillary pressure in the oil reservoir according to multiple reference capillary pressure curves; simulating and analyzing the crack expansion direction and seepage pressure during the volume fracturing of the oil reservoir to determine the three-dimensional expansion law of the crack and the parameters of the artificial crack; coupling the three-dimensional crack model with the matrix attribute model to obtain an integrated model of oil reservoir geology and engineering; establishing a numerical simulation model based on the relationship between the wet phase fluid saturation and the capillary pressure and the integrated model of oil reservoir geology and engineering; numerically simulating the oil reservoir development process through the numerical simulation model to obtain data simulation results of the oil reservoir at different development stages; determining the contribution of displacement and imbibition to oil production in the oil reservoir at different development stages according to the data simulation results, and providing a theoretical basis and technical support for oil reservoir exploitation. BRIEF DESCRIPTION OF THE DRAWINGS

[0068] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0069] Figure 1 A method for determining the contribution of unconventional oil reservoirs to oil production provided in the embodiment of the present application Figure 1 ;

[0070] Figure 2 A method for determining the contribution of unconventional oil reservoirs to oil production provided in the embodiment of the present application Figure 2 ;

[0071] Figure 3 A schematic diagram of the structure of a device for determining the contribution degree of unconventional oil reservoir production provided in this application;

[0072] Figure 4 A schematic diagram of the structure of an unconventional oil reservoir production contribution determination device provided in this application.

[0073] The above drawings have shown clear embodiments of the present application, which will be described in more detail later. These drawings and text descriptions are not intended to limit the scope of the present application in any way, but to illustrate the concept of the present application to those skilled in the art by referring to specific embodiments. DETAILED DESCRIPTION

[0074] In order to make the purpose, technical solutions and advantages of this application clearer, the technical solutions in this application will be clearly and completely described below in conjunction with the drawings in this application. Obviously, the described embodiments are part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0075] The terms "first", "second", "third", "fourth", etc. (if any) in the description and claims of the present invention and the above drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the numbers used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in sequences other than those illustrated or described herein.

[0076] In the embodiments of the present application, the words "exemplary" or "for example" are used to indicate examples, illustrations or descriptions. Any embodiment or design described as "exemplary" or "for example" in the present application should not be interpreted as being more preferred or more advantageous than other embodiments or designs. Specifically, the use of words such as "exemplary" or "for example" is intended to present related concepts in a specific way.

[0077] For unconventional oil reservoirs with extremely low permeability, such as tight oil reservoirs and shale oil reservoirs, it is difficult to implement effective fluid displacement due to the difficulty of water injection development. Therefore, the current development of such low permeability oil reservoirs mainly relies on large-scale volume fracturing technology of horizontal wells to create numerous artificial fractures, supplemented by water injection huff-and-puff technology.

[0078] In the production area after fracturing, when water injection and huff-and-puff are used for oil production, spontaneous imbibition driven by capillary pressure becomes a key mechanism in the oil production process. However, the imbibition process is not only affected by the capillary pressure alone, but also by the displacement pressure difference, which makes the imbibition mechanism more complicated.

[0079] At present, most of the research on imbibition oil recovery focuses on the core level, analyzing the mobility of crude oil, the imbibition dynamics and its influencing factors in an indirect and qualitative way. However, at the macroscopic scale, there is a lack of a method that can quantitatively evaluate the contribution of displacement and imbibition to the recovery of unconventional oil reservoirs.

[0080] In view of the above problems existing in the prior art, the present application provides a method for determining the contribution of unconventional oil reservoirs to oil recovery. The method classifies and evaluates the pore structure distribution of different types of reservoirs for unconventional oil reservoirs after fracturing, describes the crack expansion law and partition seepage characteristics after fracturing, establishes a geological engineering integration model of fracture-microcrack-matrix coupling and a numerical simulation model of displacement-imbibition mechanism, and analyzes the contribution of displacement and imbibition to the recovery rate at each development stage of the oil reservoir.

[0081] The technical solution of the present application and how the technical solution of the present application solves the above-mentioned technical problems are described in detail below with specific embodiments. The following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be repeated in some embodiments. The embodiments of the present application will be described below in conjunction with the accompanying drawings.

[0082] Figure 1 This is a method for determining the contribution of unconventional oil reservoirs to oil production provided in the embodiment of the present application. Figure 1 .like Figure 1 As shown, the method for determining the contribution degree of unconventional oil reservoir oil production provided in this embodiment includes:

[0083] S101: Obtain reference capillary pressure curves of different types of oil reservoirs, and determine a relationship characterization model between the wetting phase fluid saturation and the capillary pressure in the oil reservoir according to a plurality of reference capillary pressure curves.

[0084] The capillary pressure curve is the relationship curve between the capillary pressure and the wet phase saturation in the porous medium of the reservoir. The relationship characterization model between the wet phase fluid saturation and the capillary pressure is used to describe the dimensionless relationship between the capillary pressure and the fluid saturation in the reservoir.

[0085] Specifically, in this embodiment, a tight / shale oil reservoir is selected as the research object. It is understandable that different types of tight / shale oil reservoirs have different permeabilities and porosities. Therefore, it is necessary to select representative real cores according to the porosity and permeability limits of different types of tight / shale oil reservoirs, conduct high-pressure mercury injection experiments on the selected cores, and set the maximum mercury injection pressure, which may be 200 MPa, for example. By analyzing and processing the mercury injection experiment results of different types of cores, reference capillary pressure curves of different types of reservoirs are determined.

[0086] It can be understood that since a certain capillary pressure corresponds to a certain pore throat radius, the capillary pressure curve actually contains the distribution law of the pore throat of the rock sample. Specifically, according to the mercury injection pressure value, the expression for calculating the pore throat radius is:

[0087]

[0088] Furthermore, the J function and the wetting phase fluid saturation S are converted according to the reference capillary pressure curves of different types of reservoirs. w Relationship curve, and then fit to determine the J function of different types of reservoirs~S w Relational representation model.

[0089] Among them, the J function is defined as the ratio of the measured capillary pressure to the reference capillary pressure. The conversion relationship between the J function and the reference capillary pressure is as follows:

[0090]

[0091] in, is the mercury-air interfacial tension, is the oil-water interfacial tension, is the air-water interfacial tension; is the mercury injection pressure, is the oil-water capillary pressure, is the gas-water capillary pressure; is the mercury-air contact angle, is the oil-water contact angle, is the air-water contact angle; is the permeability; is the porosity.

[0092] Furthermore, by statistically analyzing the pore structure characteristic parameters such as displacement pressure, pore throat radius distribution, average pore throat radius, maximum pore throat radius, and sorting coefficient, the microscopic pore structure characteristics of different types of tight / shale reservoirs can also be obtained.

[0093] By obtaining and analyzing the reference capillary pressure curves of different types of reservoirs and establishing a characterization model of the relationship between wetting phase fluid saturation and capillary pressure based on these data, an important reference basis can be provided for reservoir evaluation and development.

[0094] S102: Simulating and analyzing the crack expansion direction and seepage pressure during the volume fracturing process of the oil reservoir, determining the three-dimensional expansion law of the volume fracturing cracks of the oil reservoir, and obtaining artificial fracture parameters according to the three-dimensional expansion law.

[0095] It can be understood that according to the geological data such as the geological structure, lithology, porosity, permeability, etc. of the reservoir and the injection pressure, displacement and other data during the volume fracturing construction, numerical methods such as finite element analysis are used to simulate the expansion behavior of fractures in different directions and depths.

[0096] Furthermore, by calculating the seepage pressure at each point during the crack propagation process, the influence of pressure distribution on crack propagation is analyzed, and the crack propagation direction under different stress fields is determined.

[0097] Furthermore, the fracture propagation model can be optimized by adjusting the control parameters, and the simulation results can be compared with the field logging data and production data to verify the accuracy of the model.

[0098] Through the above steps, the fracture extension and seepage pressure during reservoir volume fracturing can be systematically simulated, thereby determining the key parameters of artificial fractures and providing a scientific basis for reservoir development.

[0099] S103: establishing a three-dimensional fracture model according to the artificial fracture parameters, coupling the three-dimensional fracture model with a matrix property model to obtain an integrated reservoir geology and engineering model.

[0100] It can be understood that in this embodiment, the fracture geometric model is established by using fracture parameters, the geological model of the reservoir is established using geological data, including porosity, permeability, saturation and net-to-gross ratio, etc., and the matrix attribute model is gridded to couple with the fracture model.

[0101] Furthermore, it is ensured that the fracture model and matrix model are spatially aligned and meshed consistently. By determining the interactions between fractures and matrix, such as the effect of fractures on matrix stress and fluid conduction, the fracture model is integrated with the matrix property model to establish a unified reservoir geology-engineering integrated model.

[0102] A three-dimensional fracture model is established based on the artificial fracture parameters, and it is coupled with the matrix property model to obtain an integrated reservoir geological and engineering model. This step can more accurately understand the characteristics and engineering conditions of the reservoir and provide a scientific basis for reservoir exploitation.

[0103] S104: Establishing a numerical simulation model based on the relationship representation model and the reservoir geology-engineering integrated model.

[0104] It can be understood that the relationship characterization model between the wet phase fluid saturation and capillary pressure in the reservoir reflects the properties of the fluid in the reservoir, and the geological engineering integrated model comprehensively reflects the characteristics of the matrix and fractures. The numerical simulation model constructed based on the two can comprehensively reflect the geological conditions of the reservoir.

[0105] Furthermore, in this embodiment, in order to better simulate the flow field distribution characteristics of the reservoir after fracturing, the target study area is divided into main fracture areas, fracturing transformation areas and matrix untransformed areas.

[0106] It can be understood that displacement mainly occurs in the main fracture area, where the fluid is rapidly replaced by a larger driving force; capillary imbibition mainly occurs in the fracturing zone and the matrix un-transformed zone, where the fluid is sucked into tiny pores and fractures through capillary action.

[0107] This numerical simulation model can accurately simulate the fluid flow behavior of the reservoir after fracturing and reflects the fluid dynamic mechanism under the dual effects of displacement and capillary imbibition.

[0108] S105: numerically simulate the oil reservoir development process through the numerical simulation model to obtain data simulation results of the oil reservoir at different development stages.

[0109] It can be understood that the basic parameters of the reservoir development process, including but not limited to geological structure data, fluid property parameters, etc., are input into the numerical simulation model. After receiving the above parameters, the numerical simulation model simulates the dynamic changes of the fluid in the reservoir at different development stages, and then determines the key characteristics such as the pressure distribution changes and saturation distribution of the fluid in the reservoir.

[0110] Furthermore, the pressure field map and saturation field map of each development stage were output based on the numerical simulation model. Among them, the pressure field map intuitively shows the pressure distribution at different locations inside the reservoir and its changing trend over time. The saturation field map depicts the spatial distribution of fluids in the reservoir and its dynamic changes.

[0111] S106: Analyze and process the plurality of data simulation results to obtain analysis results, and determine the contribution of displacement and imbibition to oil production in different development stages of the oil reservoir according to the analysis results.

[0112] It can be understood that according to the pressure field map output by the numerical simulation model, the displacement pressure difference at different locations in the target study area can be determined. Among them, the displacement pressure difference reflects the pressure difference between the front and rear of the fluid and is the main driving force of the fluid displacement process.

[0113] Furthermore, based on the relative size of the displacement pressure difference and the capillary pressure in the reservoir, the target study area is divided into a displacement-dominated area, a displacement-imbibition synergistic area, and an imbibition-dominated area.

[0114] Furthermore, the pressure field diagrams and saturation field diagrams at different time points are compared to observe the fluid distribution and dynamic changes, and then determine the contribution of displacement and imbibition to oil recovery at different development stages of the reservoir.

[0115] Through this process, the contribution of each area to the overall fluid dynamics and recovery effect at different development stages can be quantified, so as to formulate a more scientific and reasonable mining plan.

[0116] The embodiment of the present application provides a method for determining the contribution degree of unconventional oil reservoir oil production. The method determines the relationship between the wet phase fluid saturation and the capillary pressure in the oil reservoir according to multiple reference capillary pressure curves; simulates and analyzes the fracture expansion direction and the seepage pressure during the volume fracturing of the oil reservoir to determine the three-dimensional expansion law of the fracture and the parameters of the artificial fracture; couples the three-dimensional fracture model with the matrix property model to obtain an integrated reservoir geological engineering model; establishes a numerical simulation model based on the relationship between the wet phase fluid saturation and the capillary pressure and the integrated reservoir geological engineering model; numerically simulates the oil reservoir development process through the numerical simulation model to obtain data simulation results of the oil reservoir at different development stages; determines the contribution degree of displacement and imbibition to oil production in the oil reservoir at different development stages according to the data simulation results, and provides a theoretical basis and technical support for oil reservoir exploitation.

[0117] Figure 2 A method for determining the contribution of unconventional oil reservoirs to oil production provided in the embodiment of the present application Figure 2 This embodiment is in Figure 1 Based on the embodiment, a possible implementation method of the method for determining the contribution degree of unconventional oil reservoir oil production is described in detail. Figure 2 As shown, the method includes:

[0118] S201: Obtain reference capillary pressure curves of different types of oil reservoirs, and determine a relationship characterization model between the wetting phase fluid saturation and the capillary pressure in the oil reservoir according to a plurality of reference capillary pressure curves.

[0119] Among them, step S201 is similar to the above step S101 and will not be repeated here.

[0120] S202: Acquire actual fracturing data information.

[0121] Among them, the actual fracturing data information is the real-time point-in-second data collected during the actual fracturing construction process, including but not limited to key parameters such as sand addition ratio, oil pressure, casing pressure, discharge flow rate and casing flow rate.

[0122] Acquiring the second-point data during the actual fracturing process is helpful in determining the three-dimensional expansion law of the volume fracturing cracks based on the above data information in the subsequent steps.

[0123] S203: Establish a stress field-seepage coupling mathematical model of the target study area, and simulate and analyze the crack extension direction and seepage pressure based on the extended finite element method to obtain simulation analysis results.

[0124] The target study area is the area of ​​actual oil reservoir exploitation. The stress field-seepage coupling mathematical model is used to describe the interaction between fluid flow and the stress state of rock and soil.

[0125] Specifically, in this embodiment, based on the displacement discontinuity theory and the principle of fracture mechanics, a stress field-seepage coupling mathematical model of the target study area is established, and the crack extension direction and seepage pressure are simulated and analyzed based on the extended finite element method.

[0126] It can be understood that the displacement discontinuity theory is an effective fracture analysis method that takes into account the displacement discontinuity on the crack surface. The principle of fracture mechanics provides the criteria and calculation method for crack extension, and is an important basis for establishing the stress field-seepage coupling mathematical model. The stress field-seepage coupling mathematical model comprehensively considers the stress state of the rock and soil mass, the seepage characteristics, and the interaction between them.

[0127] By simulating and analyzing the crack expansion direction and seepage pressure, the simulation analysis results are obtained, which is conducive to determining the expansion law of volume fracturing cracks in the oil reservoir according to the results in the subsequent steps.

[0128] S204: Determine the three-dimensional expansion law of volume fracturing cracks in the oil reservoir according to the actual fracturing data information and the simulation analysis results.

[0129] It is understandable that the crack propagation behavior under different working conditions can be simulated by adjusting the control parameters and boundary conditions of the stress field-seepage coupling mathematical model. According to the simulation results, the crack propagation direction, propagation speed and the influence of seepage pressure on crack propagation are analyzed, and combined with the actual fracturing situation, the three-dimensional propagation law of volume fracturing cracks in the reservoir is determined.

[0130] It is worth noting that after the model is established, the accuracy and reliability of the model should be verified by comparing it with the actual data. If there is a large difference between the model and the actual data, the model should be adjusted and optimized.

[0131] S205: Obtaining artificial crack parameters according to the three-dimensional expansion law.

[0132] Among them, artificial fracture parameters include but are not limited to fracture half-length, fracture width, effective permeability, conductivity, skin coefficient and other parameters.

[0133] In this embodiment, based on the pump-off pressure drop data after fracturing, a limited conductivity numerical well test model of the reservoir fracturing well reflecting the above-mentioned fracture extension law is established, the pump-off pressure drop curve and the production history curve are fitted and corrected, and the artificial fracture parameters such as fracture half-length, fracture width, effective permeability, conductivity, and skin coefficient are determined.

[0134] For fractured production wells with frequent changes in working systems or co-production of oil and water, the accuracy of fracture parameter inversion interpretation can be improved through the segmented fitting method.

[0135] S206: Constructing a matrix property model according to the matrix property parameters.

[0136] The matrix attributes include but are not limited to porosity, permeability, saturation and net-to-gross ratio. The matrix attribute model reflects the physical characteristics inside the reservoir.

[0137] Specifically, in this embodiment, based on the reservoir structure model and the logging data interpretation results, the sequential Gaussian method is used to establish the sedimentary phase model and matrix attribute models such as porosity, permeability, saturation, and net-to-gross ratio.

[0138] S207: Generate a fracture attribute model based on the artificial fracture parameters and the natural fracture parameters.

[0139] Specifically, in this embodiment, based on rock mechanics theory and logging data, a single-well rock mechanics parameter model and a three-dimensional geostress model of the target area are established.

[0140] A natural fracture model is generated based on fracture properties, fracture density and cumulative density curves. Furthermore, the fracture grid properties are coarsened based on geostatistical methods to generate a fracture property model that can be used for simulation calculations, and to finely characterize the morphology and scale of natural fractures and artificial fracturing fractures of different scales.

[0141] S208: Coupling the fracture attribute model and the matrix attribute model to obtain an integrated reservoir geology and engineering model.

[0142] It is understandable that the data formats of the fracture attribute model and the matrix attribute model are unified to ensure the consistency of the data in space and time for data integration. If the grid division of the fracture attribute model and the matrix attribute model is consistent, the two can be superimposed, and the data of the fracture attribute model and the matrix attribute model can be integrated using geostatistical methods to obtain an integrated reservoir geological engineering integrated model.

[0143] S209: modifying the grid properties of the fracture-controlled transformation area in the reservoir geology-engineering integrated model by using a local grid encryption method and combining the artificial fracture parameters.

[0144] It can be understood that local mesh refinement refers to the process of meshing a specific area to be meshed more finely. Local mesh refinement can improve the numerical simulation accuracy of a specific area while ensuring the computational efficiency.

[0145] Specifically, in this embodiment, the fracture control transformation area in the oil reservoir production process can be further divided into: main fracture area and hydraulic fracture transformation area. The main fracture area includes: the main hydraulic fracture and the area directly affected by it, and the hydraulic fracture transformation area includes: the area affected by micro fractures and secondary fractures.

[0146] Furthermore, for the main fracture area, the fracturing transformation area and the matrix untransformed area, a local grid encryption method is used to modify the grid properties of the above areas according to the artificial fracture parameters obtained in the above steps, and assign permeability, porosity, fluid properties and other parameters to each grid unit.

[0147] S210: Establishing a numerical simulation model based on the relationship representation model and the reservoir geology-engineering integrated model after grid attribute correction.

[0148] Among them, the relationship characterization model is used to reflect the correlation between the wet phase fluid saturation and capillary pressure in the reservoir, and the reservoir geology and engineering integration model after grid attribute correction accurately depicts the geological conditions at different grids.

[0149] Specifically, in this embodiment, the parameters and formulas of the model characterizing the relationship between the wet phase fluid saturation and the capillary pressure and the reservoir geology-engineering integrated model after the grid attribute correction are integrated to construct a numerical simulation model for numerical simulation. Furthermore, the model is run using numerical simulation software to simulate the flow process of the fluid in the reservoir.

[0150] It can be understood that the numerical simulation model obtained by combining the relationship characterization model and the geological engineering integrated model modified according to the grid attributes can more finely describe the differential seepage laws of the main fracture area, the fracturing transformation area and the matrix untransformed area. Furthermore, it is beneficial to simulate the reservoir development process according to the numerical simulation model in the subsequent steps, and then output accurate numerical simulation results.

[0151] S211: Inputting basic parameters of the reservoir development process into the numerical simulation model.

[0152] Among them, the basic parameters of the reservoir development process include: number of grids, grid step size, reservoir depth, fracture length, injection rate, well shut-in time, etc.

[0153] By inputting the above basic parameters into the numerical simulation model, it is beneficial for the numerical simulation model to output corresponding simulation results according to the above parameters.

[0154] S212: Outputting pressure field diagrams and saturation field diagrams at different development stages through the numerical simulation model.

[0155] In this embodiment, the integrated flow simulation of the injection-well shut-off-flowback development process of tight / shale oil reservoirs is carried out through the numerical simulation model obtained in the above steps, and then the pressure field and saturation field diagrams at different development stages are obtained.

[0156] Run the model in the numerical simulation software to simulate the flow process of the fluid in different development stages. And by setting the time step and simulation time range, determine the changes of fluid pressure, saturation and other parameters over time.

[0157] S213: Using the pressure field map and the saturation field map as the data simulation results.

[0158] It can be understood that the pressure field and saturation field diagrams at different development stages can be obtained through the above simulation process. According to the pressure field diagram and the saturation field diagram, the pressure value and saturation value of each grid unit at different time steps can be obtained.

[0159] S214: Obtaining a displacement pressure difference according to the pressure field diagram.

[0160] It can be understood that a point or line that can reflect the pressure change during the fluid flow process is selected in the fluid flow direction, and the corresponding pressure value is read at the selected point or line, and further, the pressure difference in the fluid flow direction is determined according to the read pressure value. Specifically, the pressure value at the outflow end can be subtracted from the pressure value at the inflow end, and the pressure difference obtained is the displacement pressure difference.

[0161] In practical applications, the size of the displacement pressure difference is of great significance for evaluating fluid displacement effects and optimizing development strategies.

[0162] S215: According to the relative magnitudes of the displacement pressure difference and the capillary pressure, the target study area is divided into a displacement-dominated area, a displacement-imbibition synergistic area and an imbibition-dominated area.

[0163] In this embodiment, according to the relative magnitude of the displacement pressure difference ΔP and the capillary pressure Pc, the underground fluid flow area is divided into a displacement-dominated area, a displacement-imbibition synergistic area and an imbibition-dominated area.

[0164] It can be understood that in the displacement-dominated area, the displacement pressure difference ΔP is significantly greater than the capillary pressure Pc; in the displacement-imbibition synergistic area, the displacement pressure difference ΔP is equivalent to the capillary pressure Pc, and the two act together on the fluid flow; in the imbibition-dominated area, the capillary pressure Pc is significantly greater than the displacement pressure difference ΔP.

[0165] Specifically, the region with ΔP>1.2Pc is divided into the displacement-dominated region, the region with 0.8Pc<ΔP<1.2Pc is divided into the displacement-imbibition synergistic region, and the region with ΔP<0.8Pc is divided into the imbibition-dominated region.

[0166] S216: Determine the contribution of displacement dominance, displacement-imbibition synergy, and imbibition dominance to oil recovery at different development stages.

[0167] Understandably, the properties of the fluids in the reservoir change over time, and the extent to which displacement and imbibition act at different times also changes accordingly.

[0168] Specifically, in the early stage of production, displacement is the main driving force of development; as development proceeds, displacement-imbibition synergy dominates; at the end of development, due to the decrease in formation energy, imbibition becomes the main driving force of development.

[0169] Determining the extent of displacement dominance, displacement-imbibition synergy, and imbibition dominance at different development stages, and then continuously optimizing and adjusting the mining strategy, is conducive to improving the recovery factor.

[0170] In an optional embodiment, a method for determining the contribution of unconventional oil reservoirs to oil production also includes: based on the results of the pore structure classification evaluation of the oil reservoir, regressing the relationship between the average pore throat radius and the permeability, considering the influence of the wetting angle and interfacial tension to construct displacement pressure difference-permeability charts for different types of reservoirs, and determining the influence of the three mechanical mechanisms of displacement dominance, displacement-imbibition synergy, and imbibition dominance on the recovery factor at the reservoir scale.

[0171] This method can quickly and quantitatively evaluate the displacement-imbibition production law of tight / shale reservoirs, and provide guidance for optimizing the coordinated injection-production of displacement-imbibition throughout the life cycle and improving the degree of matrix utilization.

[0172] The present application provides a method for determining the contribution of unconventional oil reservoirs to oil production. The method acquires actual fracturing data information, establishes a stress field-seepage coupling mathematical model of a target study area, simulates and analyzes the crack expansion direction and seepage pressure, obtains simulation analysis results, determines the three-dimensional expansion law of volume fracturing cracks in the reservoir according to the actual fracturing data information and the simulation analysis results, integrates the crack attribute model and the matrix attribute model to obtain an integrated reservoir geological engineering model, and uses a local grid encryption method and combined with artificial fracture parameters to encrypt the grid of the fracture-controlled transformation area in the integrated reservoir geological engineering model. The attributes are corrected, and a numerical simulation model is established according to the relationship characterization model and the reservoir geology and engineering integrated model corrected by the grid attributes. The pressure field map and saturation field map at different development stages are output by the numerical simulation model, and the displacement pressure difference is obtained according to the pressure field map. According to the relative size of the displacement pressure difference and the capillary pressure, the target study area is divided into a displacement-dominated area, a displacement-imbibition synergistic area and an imbibition-dominated area. The contribution of displacement-dominated, displacement-imbibition synergistic and imbibition-dominated oil production in different development stages is determined, which provides a theoretical basis and technical support for the reservoir exploitation process and is helpful to improve the recovery rate of the reservoir.

[0173] Figure 3 This is a schematic diagram of the structure of a device for determining the contribution degree of unconventional oil reservoir production provided in this application. Figure 3As shown, the device 300 for determining the contribution degree of unconventional oil reservoir production provided in this embodiment includes:

[0174] An acquisition module 301 is used to acquire reference capillary pressure curves of different types of oil reservoirs;

[0175] A determination module 302 is used to determine a relationship characterization model between the wetting phase fluid saturation and the capillary pressure in the oil reservoir according to a plurality of reference capillary pressure curves;

[0176] Processing module 303 is used to simulate and analyze the crack expansion direction and seepage pressure during the volume fracturing process of the oil reservoir, determine the three-dimensional expansion law of the volume fracturing cracks of the oil reservoir, and obtain artificial fracture parameters according to the three-dimensional expansion law;

[0177] Establishing a three-dimensional fracture model according to the artificial fracture parameters, coupling the three-dimensional fracture model with a matrix property model to obtain an integrated reservoir geology and engineering model;

[0178] Establishing a numerical simulation model based on the relationship representation model and the reservoir geology and engineering integration model;

[0179] The numerical simulation model is used to numerically simulate the oil reservoir development process to obtain data simulation results of the oil reservoir at different development stages;

[0180] The plurality of data simulation results are analyzed and processed to obtain analysis results, and the contribution of displacement and imbibition to oil production at different development stages of the oil reservoir is determined according to the analysis results.

[0181] Optionally, the acquisition module 301 is also used to acquire actual fracturing data information;

[0182] The processing module 303 is also used to establish a stress field-seepage coupling mathematical model of the target study area, and simulate and analyze the fracture extension direction and seepage pressure based on the extended finite element method to obtain simulation analysis results;

[0183] The determination module 302 is further used to determine the three-dimensional expansion law of volume fracturing cracks in the oil reservoir according to the actual fracturing data information and the simulation analysis results.

[0184] Optionally, the processing module 303 is further used to construct a matrix property model according to the matrix property parameters;

[0185] generating a fracture attribute model based on the artificial fracture parameters and the natural fracture parameters;

[0186] The fracture attribute model and the matrix attribute model are coupled to obtain an integrated reservoir geology and engineering model.

[0187] Optionally, the processing module 303 is further used to modify the grid properties of the fracture-controlled transformation area in the reservoir geology-engineering integrated model by using a local grid encryption method and combining the artificial fracture parameters;

[0188] A numerical simulation model is established based on the relationship representation model and the reservoir geology and engineering integrated model after grid attribute correction.

[0189] Optionally, the processing module 303 is further used to input basic parameters of the reservoir development process into the numerical simulation model;

[0190] Outputting pressure field diagrams and saturation field diagrams at different development stages through the numerical simulation model;

[0191] The pressure field map and the saturation field map are taken as the data simulation results.

[0192] Optionally, the processing module 303 is further used to obtain a displacement pressure difference according to the pressure field map;

[0193] According to the relative magnitude of the displacement pressure difference and the capillary pressure, the target research area is divided into a displacement-dominated area, a displacement-imbibition synergistic area and an imbibition-dominated area;

[0194] The determination module 302 is also used to determine the contribution of displacement dominance, displacement-imbibition synergy and imbibition dominance to oil recovery in oil reservoirs at different development stages.

[0195] Optionally, the processing module 303 is further used to classify and evaluate the pore structure distribution of the oil reservoir according to the porosity and permeability of the oil reservoir to obtain an evaluation result;

[0196] According to the pore structure classification evaluation results of the oil reservoir, a displacement pressure difference-permeability map of the oil reservoir is constructed;

[0197] The determination module 302 is further used to determine the influence of displacement dominance, displacement-imbibition synergy and imbibition dominance on the recovery factor according to the displacement pressure difference-permeability chart;

[0198] This embodiment provides a device for evaluating the capacity of an energy storage power station, which can execute the method provided in the above method embodiment. Its implementation principle and technical effect are similar, and this embodiment will not be described in detail here.

[0199] Figure 4 The schematic diagram of the structure of a device for determining the contribution of unconventional oil reservoirs to oil production provided in this application. Figure 4As shown, the unconventional oil reservoir oil production contribution determination device provided in the present application, the unconventional oil reservoir oil production contribution determination device 400 includes: a receiver 401, a transmitter 402, a processor 403 and a memory 404.

[0200] Receiver 401, for receiving instructions and data;

[0201] A transmitter 402, used for sending instructions and data;

[0202] Memory 404, for storing computer-executable instructions;

[0203] The processor 403 is used to execute the computer-executable instructions stored in the memory 404 to implement the various steps executed by the method for determining the oil production contribution degree of unconventional oil reservoirs in the above embodiment. For details, please refer to the relevant description in the above embodiment of the method for determining the oil production contribution degree of unconventional oil reservoirs.

[0204] Optionally, the memory 404 may be independent or integrated with the processor 403 .

[0205] When the memory 404 is independently provided, the electronic device further includes a bus for connecting the memory 404 and the processor 403 .

[0206] The present application also provides a computer storage medium, in which computer execution instructions are stored. When a processor executes the computer execution instructions, a method for determining the contribution degree of unconventional oil reservoir oil production as performed by the above-mentioned device for determining the contribution degree of oil reservoir oil production is implemented.

[0207] It will be appreciated by those skilled in the art that all or some of the steps, systems, and functional modules / units in the methods disclosed above may be implemented as software, firmware, hardware, and appropriate combinations thereof. In hardware implementations, the division between the functional modules / units mentioned in the above description does not necessarily correspond to the division of physical components; for example, a physical component may have multiple functions, or a function or step may be performed by several physical components in cooperation. Some or all physical components may be implemented as software executed by a processor, such as a central processing unit, a digital signal processor, or a microprocessor, or implemented as hardware, or implemented as an integrated circuit, such as an application-specific integrated circuit. Such software may be distributed on a computer-readable medium, which may include a computer storage medium (or non-transitory medium) and a communication medium (or transient medium). As is known to those skilled in the art, the term computer storage medium includes volatile and non-volatile, removable and non-removable media implemented in any method or technology for storing information (such as computer-readable instructions, data structures, program modules, or other data). Computer storage media include, but are not limited to, RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROM, digital versatile disks (DVD) or other optical disk storage, magnetic cassettes, magnetic tapes, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to store the desired information and can be accessed by a computer. In addition, it is well known to those skilled in the art that communication media typically contain computer-readable instructions, data structures, program modules, or other data in a modulated data signal such as a carrier wave or other transport mechanism, and may include any information delivery media.

[0208] Those skilled in the art will readily appreciate other embodiments of the present application after considering the specification and practicing the invention disclosed herein. The present application is intended to cover any modification, use or adaptation of the present application, which follows the general principles of the present application and includes common knowledge or customary techniques in the art that are not disclosed in the present application. The specification and examples are intended to be exemplary only, and the true scope and spirit of the present application are indicated by the following claims.

[0209] It should be understood that the present application is not limited to the precise structures that have been described above and shown in the drawings, and that various modifications and changes may be made without departing from the scope thereof. The scope of the present application is limited only by the appended claims.

Claims

1. A method for determining the contribution of unconventional oil reservoirs to oil production, characterized in that: The method comprises: Obtaining reference capillary pressure curves of different types of oil reservoirs, and determining a relationship characterization model between the saturation of the wetting phase fluid and the capillary pressure in the oil reservoir according to a plurality of reference capillary pressure curves; Simulate and analyze the crack expansion direction and seepage pressure during the volume fracturing process of the oil reservoir, determine the three-dimensional expansion law of the volume fracturing cracks in the oil reservoir, and obtain artificial fracture parameters based on the three-dimensional expansion law; Establishing a three-dimensional fracture model according to the artificial fracture parameters, coupling the three-dimensional fracture model with a matrix property model to obtain an integrated reservoir geology and engineering model; Establishing a numerical simulation model based on the relationship representation model and the reservoir geology and engineering integration model; The numerical simulation model is used to numerically simulate the oil reservoir development process to obtain data simulation results of the oil reservoir at different development stages; The plurality of data simulation results are analyzed and processed to obtain analysis results, and the contribution of displacement and imbibition to oil production at different development stages of the oil reservoir is determined according to the analysis results.

2. The method according to claim 1, characterized in that The method of simulating and analyzing the crack expansion direction and seepage pressure during the volume fracturing of the oil reservoir to determine the three-dimensional expansion law of the volume fracturing cracks in the oil reservoir includes: Obtain actual fracturing data information; Establish a stress field-seepage coupling mathematical model for the target study area, and simulate and analyze the fracture extension direction and seepage pressure based on the extended finite element method to obtain simulation analysis results; The three-dimensional expansion law of volume fracturing cracks in the oil reservoir is determined based on the actual fracturing data information and the simulation analysis results.

3. The method according to claim 1, characterized in that A three-dimensional fracture model is established according to the artificial fracture parameters, and the three-dimensional fracture model is coupled with a matrix property model to obtain an integrated reservoir geology and engineering model, including: constructing a matrix property model according to matrix property parameters; generating a fracture attribute model based on the artificial fracture parameters and the natural fracture parameters; The fracture attribute model and the matrix attribute model are coupled to obtain an integrated reservoir geology and engineering model.

4. The method according to claim 1, characterized in that According to the relationship representation model and the reservoir geology-engineering integrated model, a numerical simulation model is established, including: Modifying the grid attributes of the fracture-controlled transformation area in the reservoir geology-engineering integrated model by using a local grid encryption method and combining the artificial fracture parameters; A numerical simulation model is established based on the relationship representation model and the reservoir geology and engineering integrated model after grid attribute correction.

5. The method according to claim 1, characterized in that The numerical simulation model is used to numerically simulate the reservoir development process, and data simulation results of the reservoir at different development stages are obtained, including: inputting basic parameters of the reservoir development process into the numerical simulation model; Outputting pressure field diagrams and saturation field diagrams at different development stages through the numerical simulation model; The pressure field map and the saturation field map are taken as the data simulation results.

6. The method according to claim 1, characterized in that Analyze and process the plurality of data simulation results to obtain analysis results, and determine the contribution of displacement and imbibition to oil recovery at different development stages of the oil reservoir according to the analysis results, including: Obtaining a displacement pressure difference according to the pressure field diagram; According to the relative magnitude of the displacement pressure difference and the capillary pressure, the target research area is divided into a displacement-dominated area, a displacement-imbibition synergistic area and an imbibition-dominated area; Determine the contribution of displacement dominance, displacement-imbibition synergy and imbibition dominance to oil recovery in reservoirs at different development stages.

7. The method according to claim 1, characterized in that The method further comprises: Classify and evaluate the pore structure distribution of the oil reservoir according to the porosity and permeability of the oil reservoir to obtain an evaluation result; According to the pore structure classification evaluation results of the oil reservoir, a displacement pressure difference-permeability map of the oil reservoir is constructed; The influence of displacement dominance, displacement-imbibition synergy and imbibition dominance on the recovery factor are determined according to the displacement pressure difference-permeability diagram.

8. A device for determining the contribution degree of unconventional oil reservoir production, characterized in that: The device comprises: An acquisition module, used to obtain reference capillary pressure curves of different types of oil reservoirs; A determination module, used for determining a relationship characterization model between the saturation of the wet phase fluid and the capillary pressure in the reservoir according to a plurality of reference capillary pressure curves; A processing module is used to simulate and analyze the crack expansion direction and seepage pressure during the volume fracturing process of the oil reservoir, determine the three-dimensional expansion law of the volume fracturing cracks of the oil reservoir, and obtain artificial fracture parameters according to the three-dimensional expansion law; Establishing a three-dimensional fracture model according to the artificial fracture parameters, coupling the three-dimensional fracture model with a matrix property model to obtain an integrated reservoir geology and engineering model; Establishing a numerical simulation model based on the relationship representation model and the reservoir geology and engineering integration model; The numerical simulation model is used to numerically simulate the oil reservoir development process to obtain data simulation results of the oil reservoir at different development stages; The plurality of data simulation results are analyzed and processed to obtain analysis results, and the contribution of displacement and imbibition to oil production at different development stages of the oil reservoir is determined according to the analysis results.

9. An apparatus for determining the contribution of unconventional oil reservoirs to oil production, characterized in that: The device comprises: Memory; processor; Wherein, the memory stores computer-executable instructions; The processor executes the computer-executable instructions stored in the memory to implement a method for determining the degree of oil production contribution of unconventional oil reservoirs as described in any one of claims 1-7.

10. A computer storage medium, characterized in that: The computer storage medium stores computer execution instructions, which, when executed by a processor, are used to implement a method for determining the degree of oil production contribution of an unconventional oil reservoir as described in any one of claims 1 to 7.

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