Unconventional oil and gas reservoir brittleness evaluation method, device, equipment, medium and product

Abstract

The embodiment of the invention provides an unconventional oil and gas reservoir brittleness evaluation method, device and equipment, a medium and a product, and relates to the technical field of unconventional oil and gas reservoir exploration and development. Aiming at the problem that the brittleness evaluation and the reservoir transformation effect of the current unconventional oil and gas reservoir are not well matched, the invention provides a brittleness evaluation method according to the fracture energy and the deformation behavior of the reservoir rock, so that the brittleness of the reservoir rock is quickly and accurately evaluated, and theoretical guidance is provided for the selection of a fractured target reservoir and the design of a fractured scheme. According to the method, the basic principle that the larger the brittleness of the rock is, the smaller the energy consumed by the damage of the rock under the uniaxial / triaxial compression condition is and the smaller the deformation of the rock is is utilized, and the uniaxial / triaxial compression damage energy of the rock and the deformation of the rock during damage are combined; the compression failure energy and deformation parameters of the rock are obtained by using the stress-strain curve of the rock, and the brittleness of the reservoir rock is evaluated according to the deformation under unit energy when the rock is damaged.

Description

Technical Field

[0001] The embodiments of the present invention relate to the technical field of unconventional oil and gas reservoir exploration and development, and in particular to an unconventional oil and gas reservoir brittleness evaluation method, device, equipment, medium and product. Background Art

[0002] The geological characteristics of unconventional oil and gas reservoirs are complex, and it is difficult to accurately predict the geological sweet spots and engineering sweet spots. When fracturing unconventional oil and gas reservoirs, the brittleness evaluation of reservoir rocks is of great significance for selecting the right fracturing section, fracturing construction design, fracture network transformation volume, and oil and gas production evaluation. At present, the brittleness of reservoir rocks is mainly evaluated by means of well logging, seismic inversion, and indoor rock mechanics experiments in the field of oil and gas development. However, most brittleness index evaluation methods do not match the reservoir rock brittleness evaluation results well with the unconventional reservoir fracturing transformation effects, and the accuracy of field applications is not high.

[0003] Therefore, it is urgent to establish a rock brittleness calculation method that can accurately evaluate the brittleness of reservoir rocks and match the reservoir fracturing transformation volume. Summary of the invention

[0004] Embodiments of the present invention provide a method, device, equipment, medium and product for evaluating the brittleness of unconventional oil and gas reservoirs to at least partially solve the above-mentioned problems.

[0005] A first aspect of an embodiment of the present invention provides a method for evaluating the brittleness of unconventional oil and gas reservoirs, the method comprising: Obtain stress-strain data of target unconventional oil and gas reservoir core samples obtained in uniaxial compression or triaxial compression tests; Determine the peak strain of the target unconventional oil and gas reservoir core sample under uniaxial compression or triaxial compression according to the stress-strain data; Determining the pre-peak total energy of the target unconventional oil and gas reservoir core sample based on the peak strain; The rock brittleness value of the target unconventional oil and gas reservoir is determined based on the peak strain and the pre-peak total energy. Optionally, the stress-strain data of the core sample of the target unconventional oil and gas reservoir obtained in a uniaxial compression or triaxial compression test are obtained, including: Obtain stress-strain data from core samples of multiple fracture stages of target unconventional oil and gas reservoirs in uniaxial or triaxial compression tests; Determining the rock brittleness value of the target unconventional oil and gas reservoir according to the stress-strain data includes: According to the stress-strain data of the core samples of the multiple fracturing sections, the rock brittleness values ​​of the multiple fracturing sections are obtained; The method further comprises: Comparing the rock brittleness values ​​of the multiple fracturing sections, and determining the fracturing section with the largest rock brittleness value as the target fracturing section; Based on the target fracturing stage, an engineering sweet spot selection suggestion for the target unconventional oil and gas reservoir is output.

[0006] Optionally, obtaining stress-strain data of a target unconventional oil and gas reservoir core sample obtained in a uniaxial compression or triaxial compression test includes: Obtaining stress-strain data of a target unconventional oil and gas reservoir core sample obtained in a uniaxial or triaxial compression test under different environmental conditions, wherein the environmental conditions include: confining pressure conditions, temperature conditions and / or fluid conditions; Determining the rock brittleness value of the target unconventional oil and gas reservoir according to the stress-strain data includes: Determining the rock brittleness value of the target unconventional oil and gas reservoir under various environmental conditions based on the stress-strain data obtained under various environmental conditions; The method further comprises: According to the rock brittleness value of the target unconventional oil and gas reservoir under various environmental conditions, the brittleness evolution law of the target unconventional oil and gas reservoir as the environmental conditions change is obtained; Based on the brittle evolution law, a suggestion for selecting an engineering sweet spot for the target unconventional oil and gas reservoir is output.

[0007] Optionally, determining the pre-peak total energy of the target unconventional oil and gas reservoir core sample based on the peak strain includes: From initial strain 0 to peak strain The stress-strain curve within the range is integrated to obtain the total pre-peak energy of the rock sample. : .

[0008] Optionally, determining the rock brittleness value based on the peak strain and the pre-peak total energy includes: determining the rock brittleness value based on the following formula: ; in, BI Indicates the rock brittleness value.

[0009] Optionally, the stress-strain data is determined by the following steps: Drill and coring the target unconventional oil and gas reservoir, and process the cores into cylindrical test samples; Conducting a uniaxial or triaxial compression test on the cylindrical test sample to obtain stress-strain data of the target unconventional oil and gas reservoir core sample obtained in the uniaxial or triaxial compression test; Wherein, during the uniaxial or triaxial compression test, the stress loading rate is less than 0.05 mm / min.

[0010] A second aspect of an embodiment of the present invention provides a device for evaluating the brittleness of an unconventional oil and gas reservoir, the device comprising: An acquisition module, used to acquire stress-strain data of a target unconventional oil and gas reservoir core sample obtained in a uniaxial compression or triaxial compression test; A first determination module is used to determine the peak strain of the target unconventional oil and gas reservoir core sample under uniaxial compression or triaxial compression according to the stress-strain data; A second determination module is used to determine the pre-peak total energy of the target unconventional oil and gas reservoir core sample based on the peak strain; The third determination module is used to determine the rock brittleness value of the target unconventional oil and gas reservoir based on the peak strain and the pre-peak total energy.

[0011] A third aspect of an embodiment of the present invention provides an electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor, when executed, implements the unconventional oil and gas reservoir brittleness assessment method as described in the first aspect of the present invention.

[0012] A fourth aspect of an embodiment of the present invention provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the unconventional oil and gas reservoir brittleness evaluation method as described in the first aspect of the present invention.

[0013] A fifth aspect of an embodiment of the present invention provides a computer program product, including a computer program / instruction, which is used by a processor to implement the steps in the unconventional oil and gas reservoir brittleness assessment method as described in the first aspect of the present invention.

[0014] In the embodiment of the present invention, in view of the problem that the current evaluation of the brittleness of unconventional oil and gas reservoirs is not well matched with the effect of reservoir transformation, a method for evaluating the brittleness of unconventional oil and gas reservoirs is proposed. The method evaluates the brittleness of unconventional oil and gas reservoirs based on the relationship between the destruction energy and deformation behavior of unconventional oil and gas reservoir rocks, so as to achieve a rapid and accurate evaluation of the brittleness of reservoir rocks and provide theoretical guidance for the selection of target reservoirs for fracturing and the design of fracturing schemes. The energy and deformation required for rock destruction are direct manifestations of rock brittleness. The method for calculating the brittleness index of unconventional oil and gas reservoir rocks proposed in the present invention uses the basic principle that the greater the brittleness of the rock, the less energy is consumed for its destruction under uniaxial / triaxial compression conditions and the smaller the rock deformation. The two parameters of the uniaxial / triaxial compression destruction energy of the rock and the deformation of the rock during destruction are combined, and the compression destruction energy and deformation parameters of the rock are obtained using the stress-strain curve of the rock. The brittleness of the reservoir rock is evaluated by the deformation size under unit energy during rock destruction. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments of the present invention will be briefly introduced below. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0016] Figure 1 It is a flowchart of the steps of the unconventional oil and gas reservoir brittleness evaluation method provided by an embodiment of the present invention; Figure 2 It is the configuration of the rock mechanics test sample in the unconventional oil and gas reservoir brittleness evaluation method provided by the embodiment of the present invention; Figure 3 It is the stress-strain curve of uniaxial compression or triaxial compression and the total energy before peak ( U p )、Peak strain at failure( ε p ) Schematic diagram; Figure 4 It is a brittleness index diagram of unconventional reservoir rocks calculated in the unconventional oil and gas reservoir brittleness evaluation method provided in an embodiment of the present invention; Figure 5 is a stress-strain curve diagram of a shale core under different confining pressures in the unconventional oil and gas reservoir brittleness evaluation method provided by an embodiment of the present invention; Figure 6 It is a diagram showing the evaluation results of the brittleness of shale under different confining pressures in the unconventional oil and gas reservoir brittleness evaluation method provided by an embodiment of the present invention; Figure 7It is a diagram showing the effect of evaluating the rock brittleness of different unconventional oil and gas reservoirs in the engineering in the unconventional oil and gas reservoir brittleness evaluation method provided by an embodiment of the present invention; Figure 8 It is a typical fracturing curve of hydraulic fracturing in Case 2 provided in an embodiment of the present invention, showing the real-time data of injection pressure and displacement during the fracturing process.

[0017] Fig. 9 It is the pressure-power curve in Case 2 provided in the embodiment of the present invention, and the fracturing power is determined by the injection pressure and the displacement.

[0018] Fig.10 It is a schematic diagram of the relationship between the reservoir rock brittleness and the unit reservoir transformation volume fracturing energy of different well sections of unconventional oil and gas in different regions in the project obtained in the unconventional oil and gas reservoir brittleness evaluation method provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0019] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0020] First, the professional terms involved in the embodiments of the present invention are explained: Geological sweet spots: In oil and gas exploration and development, geological sweet spots refer to areas or layers that are rich in oil and gas and can be effectively developed under current economic and technical conditions. Specifically, geological sweet spots include the following aspects: Physical sweet spots: This refers to areas or layers with relatively high porosity and permeability in tight oil reservoirs relative to the overall tight background. Reservoir sweet spots: This refers to areas or layers with relatively high oil saturation, light oil quality (relatively low density and viscosity), relatively high pressure state (pressure coefficient greater than 1) and relatively high reserve abundance under the background of low-abundance oil. Physical sweet spots and reservoir sweet spots are collectively referred to as geological sweet spots, which are areas or layers where tight oil is relatively concentrated and enriched from a geological perspective. Geological sweet spots determine the resource potential of tight oil, while engineering sweet spots determine the development effect of tight oil. The identification and evaluation of geological sweet spots are of great guiding significance for oil and gas exploration and development, and can help determine the areas most likely to achieve high yields, thereby optimizing exploration and development strategies.

[0021] Engineering sweet spots: In engineering, especially in the field of oil and gas geology, it refers to the places where oil and gas reservoirs are easy to be developed by fracturing on the basis of geological sweet spots. In oil and gas exploration and development, "engineering sweet spots" and "geological sweet spots" together constitute the so-called "double sweet spots". Geological sweet spots refer to areas where oil and gas reservoirs are rich, while engineering sweet spots refer to places where these oil and gas reservoirs are easy to be developed by fracturing. In practical applications, the prediction of engineering sweet spots usually relies on two means: well logging and seismic exploration. Through these technical means, the geological parameters of the well points can be carefully evaluated, and the distribution of core parameters (such as porosity, permeability and brittleness) can be evaluated.

[0022] Unconventional oil and gas reservoirs: Unconventional oil and gas refers to continuous or quasi-continuous accumulations of oil and gas resources that cannot be produced in natural industrial quantities using traditional technologies and require new technologies to improve reservoir permeability or fluid viscosity in order to be economically exploited. Reservoirs are formations composed of rocks that can store and permeate fluids. Therefore, unconventional oil and gas reservoirs refer to formations composed of rocks that can store and permeate unconventional oil and gas resources.

[0023] The present invention provides a flowchart of the steps of a method for evaluating the brittleness of unconventional oil and gas reservoirs. Figure 1 Specifically, the unconventional oil and gas reservoir brittleness evaluation method comprises the following steps: S101, obtaining stress-strain data of a target unconventional oil and gas reservoir core sample obtained in a uniaxial compression or triaxial compression test; S102, determining the peak strain of the target unconventional oil and gas reservoir core sample under uniaxial compression or triaxial compression according to the stress-strain data; S103, determining the pre-peak total energy of the target unconventional oil and gas reservoir core sample based on the peak strain; S104: determining a rock brittleness value of the target unconventional oil and gas reservoir based on the peak strain and the pre-peak total energy.

[0024] In the embodiment of the present invention, in step S102, the stress-strain curve of the rock sample can be analyzed to obtain the peak strain under uniaxial / triaxial compression ( ), specifically, the maximum strain point in the stress-strain curve can be taken as the peak strain.

[0025] In the embodiment of the present invention, the area under the compressive stress-strain curve represents the work done by the external force on the rock, and also represents the energy required in the entire process from loading to rock failure. Therefore, the total pre-peak energy can be determined based on the area under the stress-strain curve and the peak strain.

[0026] The energy and deformation behavior required for rock destruction are direct manifestations of rock brittleness. The method for calculating the brittleness index of unconventional oil and gas reservoir rocks proposed in the present invention uses the basic principle that the greater the brittleness of the rock, the less energy is consumed for its destruction under uniaxial / triaxial compression conditions and the smaller the rock deformation. The two parameters of the uniaxial / triaxial compression failure energy of the rock and the deformation of the rock during destruction are combined, and the compression failure energy and deformation parameters of the rock are obtained using the stress-strain curve of the rock. The brittleness of the reservoir rock is evaluated by the deformation size under unit energy during rock destruction.

[0027] In the embodiment of the present invention, the following steps may be used to determine stress-strain data: S100, drilling and coring the target unconventional oil and gas reservoir, and processing the cores into cylindrical test samples; S200, performing a uniaxial or triaxial compression test on the cylindrical test sample to obtain stress-strain data of the target unconventional oil and gas reservoir core sample obtained in the uniaxial or triaxial compression test.

[0028] In the embodiment of the present invention, the preparation process of the test sample includes: drilling and coring the target unconventional oil and gas reservoir, and processing the core into a cylindrical test sample.

[0029] In the embodiment of the present invention, the in-situ environmental parameters such as geostress characteristics (eg, confining pressure) and temperature and fluid in the in-situ environment of the reservoir can also be obtained.

[0030] In an embodiment of the present invention, the reservoir rock compression failure test process includes: taking the test sample in the above steps to carry out a uniaxial compression test or a triaxial compression test. If conditions permit, a triaxial compression test can also be carried out under the in-situ environmental conditions of the reservoir to obtain stress-strain data of the reservoir core under uniaxial compression or triaxial compression conditions, and draw a stress-strain curve.

[0031] In the embodiment of the present invention, in actual application, the target unconventional oil and gas reservoir can be drilled and cored, and the core can be processed into a cylinder with a diameter of 50 and a height of 100 mm or a diameter of 25 and a height of 50 mm to obtain parameters such as the geostress characteristics and temperature in the in-situ environment of the reservoir.

[0032] Specifically, in the embodiment of the present invention, the sample configuration of the prepared rock mechanics test (uniaxial compression test or triaxial compression test) is as follows: Figure 2 shown.

[0033] In the embodiment of the present invention, in actual application, uniaxial or triaxial compression tests can be carried out on core samples. When conditions permit, triaxial compression tests under reservoir temperature and pressure conditions can be carried out. The loading rate must meet the quasi-static loading requirements of the rock. It is recommended that the loading rate be less than 0.05 mm / min to obtain the compressive stress-strain curve of the reservoir core under uniaxial / triaxial conditions.

[0034] In an optional embodiment, the step S103 includes: The stress-strain curve within the range is integrated to obtain the total pre-peak energy of the rock sample. : (1) In the embodiment of the present invention, in a uniaxial compression test or a triaxial compression test, load and rock sample deformation data are obtained, and then the stress of the rock is calculated ( σ ) and strain ( ε ). Further analysis of the stress-strain curve of the rock sample can be used to obtain the peak strain under uniaxial compression or triaxial compression ( ).

[0035] The embodiment of the present invention determines the pre-peak total energy based on the area of ​​the stress-strain curve at the peak strain. Specifically, the pre-peak total energy of the rock sample is obtained by integrating the stress-strain curve within the range of the initial strain 0 to the peak strain ( ).

[0036] In the present embodiment, the mechanical data (stress-strain data) obtained in the mechanical test (uniaxial compression or triaxial compression test) can be analyzed to obtain the peak strain ( ) and total energy before peak ( ). For example, the stress-strain curve of rock under uniaxial or triaxial loading and the total energy before peak ( )、Peak strain at failure( ) Schematic diagram as shown Figure 3 shown.

[0037] In an optional implementation, the step S104: The rock brittleness value is determined based on the following formula: (2) in, BI Indicates the rock brittleness value.

[0038] In the embodiment of the present invention, a brittleness index is established based on the energy and strain characteristics of rock brittle failure to obtain a rock brittleness value, and the brittleness differences of unconventional reservoir rocks can be compared based on the rock brittleness value.

[0039] In the embodiment of the present invention, the unconventional reservoir rock brittleness index calculated based on the stress-strain data obtained during the compression loading process is shown in FIG. Figure 4 As shown in the figure, the peak strain of the reservoir rock at failure during compression loading ( ε ) range is 0 ~ 0.05, and the pre-peak compressive strain energy does not exceed 5 MJ / m 3 , a reservoir rock brittleness index diagram was drawn based on peak strain and compressive strain energy. Figure 4 It can be intuitively observed that the smaller the peak strain and the smaller the pre-peak compressive strain energy, the greater the brittleness index of the rock.

[0040] In an optional embodiment, the unconventional oil and gas reservoir brittleness assessment method comprises the following steps: S201, obtaining stress-strain data of core samples of multiple fracturing stages of a target unconventional oil and gas reservoir obtained in a uniaxial or triaxial compression test; S202, obtaining rock brittleness values ​​of the multiple fracturing stages according to the stress-strain data of the core samples of the multiple fracturing stages; S203, comparing the rock brittleness values ​​of the multiple fracturing sections, and determining the fracturing section with the largest rock brittleness value as the target fracturing section; S204: Based on the target fracturing stage, outputting a recommendation for selecting an engineering sweet spot for the target unconventional oil and gas reservoir.

[0041] Based on the method provided in the embodiment of the present invention, in practical applications, the brittleness differences of reservoir rocks in different regions / fracture wells / fracture sections can be determined by comparing the brittleness values ​​corresponding to the cores of different regions or different fracturing sections or different fracturing wells, thereby guiding the engineering embodiments to select the fracturing target section based on the brittleness of different rocks, and further guiding the selection of engineering sweet spots.

[0042] In an optional embodiment, the unconventional oil and gas reservoir brittleness assessment method comprises the following steps: S301, obtaining stress-strain data of a target unconventional oil and gas reservoir core sample obtained in a uniaxial or triaxial compression test under different environmental conditions, wherein the environmental conditions include: confining pressure conditions, temperature conditions and / or fluid conditions; S302, determining the rock brittleness value of the target unconventional oil and gas reservoir under various environmental conditions according to the stress-strain data obtained under various environmental conditions; S303, according to the rock brittleness value of the target unconventional oil and gas reservoir under various environmental conditions, obtaining the brittleness evolution law of the target unconventional oil and gas reservoir as the environmental conditions change; S304: Based on the brittle evolution law, outputting engineering sweet spot selection suggestions for the target unconventional oil and gas reservoir.

[0043] In the embodiment of the present invention, the triaxial compression mechanical test can apply environmental variables such as temperature, pressure, fluid, etc. in the in-situ environment of the reservoir to evaluate the brittleness of the reservoir rock under the in-situ environmental conditions. In the embodiment of the present invention, the confining pressure, temperature and fluid conditions can also be changed during the mechanical test to predict the brittleness evolution law of the reservoir rock as the environmental variables change.

[0044] Furthermore, based on the brittleness evolution law and actual engineering requirements, engineering sweet spot selection suggestions can be output. Specifically, after evaluating the brittleness of rocks at different reservoir locations using the brittleness evaluation method provided by the embodiment of the present invention, the more brittle the reservoir rock is, the more likely it is to be a candidate for an engineering sweet spot.

[0045] In order to demonstrate the effectiveness of the method provided by the embodiment of the present invention, the present invention provides the following specific implementation cases to verify the method provided by the embodiment of the present invention.

[0046] Case 1: Brittleness evaluation of reservoir rocks under different reservoir confining pressures.

[0047] In this case, the shale core from the shale gas reservoir in a certain area of ​​Sichuan was processed into a cylinder with a diameter of 25 and a height of 50 mm. The uniaxial compression test of the core without confining pressure and the triaxial compression test under 20MPa, 40MPa and 70MPa were carried out to obtain the compressive stress-strain curves of the reservoir rock under different confining pressures, such as Figure 5 shown.

[0048] The physical and mechanical parameters of shale under different confining pressures are calculated according to the stress-strain curve, and the brittleness index of shale under different confining pressures is calculated by the brittleness index calculation formula of the present invention, as shown in Table 1 below. The relationship between the brittleness parameters of shale under different confining pressures and the confining pressure is as follows: Figure 6 As shown, with the increase of confining pressure, the brittleness of shale gradually decreases, indicating that the method provided by the embodiment of the present invention can accurately predict the effect of confining pressure on the brittleness of reservoir rock.

[0049] Table 1 Elastic physical parameters and brittleness values ​​of shale under different confining pressures

[0050] Case 2: Relationship between reservoir rock brittleness evaluation of fracturing sections in different regions and fracturing energy per unit reservoir stimulation volume.

[0051] In this case, cores from different well sections of unconventional oil and gas reservoirs (tight gas and shale gas) were collected and processed into cylinders with a diameter of 25 and a height of 50 mm. Triaxial compression tests were carried out on the cores under corresponding reservoir confining conditions without confining pressure, and stress-strain curves of different reservoir rocks were obtained. The brittleness index of different reservoir rocks was calculated using the method provided by the present invention, such as Figure 7 A typical hydraulic fracturing curve is shown in Figure 8 As shown in the figure, the real-time data of injection pressure and displacement during fracturing are shown, and the relationship between injection pressure and displacement over time is further shown. Multiplying the injection pressure by the displacement gives Fig. 9 The fracturing power curve is shown in Figure 2, where the fracturing power is determined by the injection pressure and displacement. The total fracturing energy of the fracturing well section is obtained by numerically integrating the fracturing power curve over the entire fracturing construction time. The total fracturing energy and total transformation volume of different well sections in this case are detailed in Table 2. The total fracturing energy is divided by the fractured reservoir transformation volume (SRV) of the corresponding well section to obtain the fracturing energy required for transformation per SRV. The relationship between the reservoir rock brittleness (BI) of different well sections and the fracturing energy required per unit SRV is shown in Table 2. Fig.10 . Fig.10 This shows that the larger the brittleness index is, the more brittle the reservoir rock is. The more brittle the reservoir rock is, the easier it is to be fractured, and the smaller the energy required to transform a unit SRV is. Fig.10 It also proves the engineering applicability and great accuracy of the reservoir rock brittleness evaluation method provided by the embodiment of the present invention.

[0052] Table 2 Total fracturing energy and total stimulation volume of different fracturing sections

[0053] Therefore, in the embodiment of the present invention, based on the real on-site construction data, the engineering applicability of the brittleness evaluation method proposed in the embodiment of the present invention is verified.

[0054] In the embodiment of the present invention, it is recommended to use 3 to 5 cores when conducting rock mechanics tests.

[0055] Furthermore, in the present application, the fracturing energy required for the transformation unit SRV of the target unconventional oil and gas reservoir can be determined based on the total pre-peak energy of the target unconventional oil and gas reservoir, and the total fracturing energy for the fracturing reservoir transformation volume of the corresponding well section of the target unconventional oil and gas reservoir can be further determined, and engineering recommendations on injection pressure and displacement can be further output.

[0056] Based on the same inventive concept, an embodiment of the present invention further provides a device for evaluating the brittleness of an unconventional oil and gas reservoir, the device comprising: An acquisition module, used to acquire stress-strain data of a target unconventional oil and gas reservoir core sample obtained in a uniaxial compression or triaxial compression test; A first determination module is used to determine the peak strain of the target unconventional oil and gas reservoir core sample under uniaxial compression or triaxial compression according to the stress-strain data; A second determination module is used to determine the pre-peak total energy of the target unconventional oil and gas reservoir core sample based on the peak strain; The third determination module is used to determine the rock brittleness value of the target unconventional oil and gas reservoir based on the peak strain and the pre-peak total energy.

[0057] Optionally, the acquisition module is specifically used to: acquire stress-strain data of core samples of multiple fracturing stages of a target unconventional oil and gas reservoir obtained in a uniaxial or triaxial compression test; The third determination module is specifically used to obtain the rock brittleness value of each of the multiple fracturing sections according to the stress-strain data of the core samples of the multiple fracturing sections; The device also includes: A comparison module, used for comparing the rock brittleness values ​​of the multiple fracturing sections, and determining the fracturing section with the largest rock brittleness value as the target fracturing section; An output module is used to output an engineering sweet spot selection suggestion for the target unconventional oil and gas reservoir based on the target fracturing stage.

[0058] Optionally, the acquisition module is specifically used to: acquire stress-strain data of a target unconventional oil and gas reservoir core sample obtained in a uniaxial or triaxial compression test under different environmental conditions, wherein the environmental conditions include: confining pressure conditions, temperature conditions and / or fluid conditions; The third determination module is specifically used to: determine the rock brittleness value of the target unconventional oil and gas reservoir under various environmental conditions according to the stress-strain data obtained under various environmental conditions; The device also includes: An analysis module, for obtaining the brittleness evolution law of the target unconventional oil and gas reservoir as the environmental conditions change according to the rock brittleness value of the target unconventional oil and gas reservoir under various environmental conditions; The output module is used to output engineering sweet spot selection suggestions for the target unconventional oil and gas reservoir based on the brittle evolution law.

[0059] Optionally, the second determining module is specifically configured to: From initial strain 0 to peak strain The stress-strain curve within the range is integrated to obtain the total pre-peak energy of the rock sample. : .

[0060] Optionally, the third determining module is specifically configured to: The rock brittleness value is determined based on the following formula: ; in, BI Indicates the rock brittleness value.

[0061] Optionally, the stress-strain data is determined by the following steps: Drill and coring the target unconventional oil and gas reservoir, and process the cores into cylindrical test samples; Conducting a uniaxial or triaxial compression test on the cylindrical test sample to obtain stress-strain data of the target unconventional oil and gas reservoir core sample obtained in the uniaxial or triaxial compression test; Wherein, during the uniaxial or triaxial compression test, the stress loading rate is less than 0.05 mm / min.

[0062] Based on the same inventive concept, an embodiment of the present invention also provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes, the steps in the method for evaluating the brittleness of unconventional oil and gas reservoirs as described in any of the above embodiments are implemented.

[0063] Based on the same inventive concept, an embodiment of the present invention further provides a computer-readable storage medium on which a computer program is stored. When the program is executed by a processor, the steps in the unconventional oil and gas reservoir brittleness evaluation method described in any of the above embodiments are implemented.

[0064] Based on the same inventive concept, an embodiment of the present invention provides a computer program product, including a computer program / instruction, which, when executed by a processor, implements the steps in the unconventional oil and gas reservoir brittleness evaluation method described in any of the above embodiments.

[0065] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0066] It will be appreciated by those skilled in the art that the embodiments of the present invention may be provided as methods, devices, or computer program products. Therefore, the embodiments of the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the embodiments of the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program codes.

[0067] The embodiments of the present invention are described with reference to the flowcharts and / or block diagrams of the methods, terminal devices (apparatus), and computer program products according to the embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of the processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable terminal device to generate a machine, so that the instructions executed by the processor of the computer or other programmable terminal device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0068] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable terminal device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce a manufactured product including an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0069] These computer program instructions can also be loaded onto a computer or other programmable terminal device so that a series of operating steps are executed on the computer or other programmable terminal device to produce a computer-implemented process, thereby providing instructions for executing on the computer or other programmable terminal device to implement the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0070] Although the preferred embodiments of the present invention have been described, those skilled in the art may make additional changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the embodiments of the present invention.

[0071] Finally, it should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or terminal device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or terminal device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or terminal device including the elements.

[0072] The above is a detailed introduction to the unconventional oil and gas reservoir brittleness evaluation method provided by the present invention. Specific examples are used in this article to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation method and application scope. In summary, the content of this specification should not be understood as a limitation on the present invention.

Claims

1. A method for evaluating the brittleness of unconventional oil and gas reservoirs, characterized in that: The method comprises: Obtain stress-strain data of target unconventional oil and gas reservoir core samples obtained in uniaxial compression or triaxial compression tests; Determine the peak strain of the target unconventional oil and gas reservoir core sample under uniaxial compression or triaxial compression according to the stress-strain data; Determining the pre-peak total energy of the target unconventional oil and gas reservoir core sample based on the peak strain; The rock brittleness value of the target unconventional oil and gas reservoir is determined based on the peak strain and the pre-peak total energy.

2. The unconventional oil and gas reservoir brittleness evaluation method according to claim 1, characterized in that: Obtain stress-strain data of target unconventional oil and gas reservoir core samples in uniaxial compression or triaxial compression tests, including: Obtain stress-strain data from core samples of multiple fracture stages of target unconventional oil and gas reservoirs in uniaxial or triaxial compression tests; Determining the rock brittleness value of the target unconventional oil and gas reservoir according to the stress-strain data includes: According to the stress-strain data of the core samples of the multiple fracturing sections, the rock brittleness values ​​of the multiple fracturing sections are obtained; The method further comprises: Comparing the rock brittleness values ​​of the multiple fracturing sections, and determining the fracturing section with the largest rock brittleness value as the target fracturing section; Based on the target fracturing stage, an engineering sweet spot selection suggestion for the target unconventional oil and gas reservoir is output.

3. The unconventional oil and gas reservoir brittleness evaluation method according to claim 1, characterized in that: Obtain stress-strain data of target unconventional oil and gas reservoir core samples in uniaxial compression or triaxial compression tests, including: Obtaining stress-strain data of a target unconventional oil and gas reservoir core sample obtained in a uniaxial or triaxial compression test under different environmental conditions, wherein the environmental conditions include: confining pressure conditions, temperature conditions and / or fluid conditions; Determining the rock brittleness value of the target unconventional oil and gas reservoir according to the stress-strain data includes: Determining the rock brittleness value of the target unconventional oil and gas reservoir under various environmental conditions based on the stress-strain data obtained under various environmental conditions; The method further comprises: According to the rock brittleness value of the target unconventional oil and gas reservoir under various environmental conditions, the brittleness evolution law of the target unconventional oil and gas reservoir as the environmental conditions change is obtained; Based on the brittle evolution law, a suggestion for selecting an engineering sweet spot for the target unconventional oil and gas reservoir is output.

4. The unconventional oil and gas reservoir brittleness evaluation method according to claim 1, characterized in that: Determining the total pre-peak energy of the target unconventional oil and gas reservoir core sample based on the peak strain includes: From initial strain 0 to peak strain The stress-strain curve within the range is integrated to obtain the total pre-peak energy of the rock sample. : .

5. The unconventional oil and gas reservoir brittleness evaluation method according to claim 4, characterized in that: Determining the rock brittleness value based on the peak strain and the pre-peak total energy includes: determining the rock brittleness value based on the following formula: ； in, BI Indicates the rock brittleness value.

6. The unconventional oil and gas reservoir brittleness evaluation method according to any one of claims 1 to 5, characterized in that: The stress-strain data are determined using the following steps: Drill and coring the target unconventional oil and gas reservoir, and process the cores into cylindrical test samples; Conducting a uniaxial or triaxial compression test on the cylindrical test sample to obtain stress-strain data of the target unconventional oil and gas reservoir core sample obtained in the uniaxial or triaxial compression test; Wherein, during the uniaxial or triaxial compression test, the stress loading rate is less than 0.05 mm / min.

7. An unconventional oil and gas reservoir brittleness evaluation device, characterized in that: The unconventional oil and gas reservoir brittleness evaluation device comprises: An acquisition module, used to acquire stress-strain data of a target unconventional oil and gas reservoir core sample obtained in a uniaxial compression or triaxial compression test; A first determination module is used to determine the peak strain of the target unconventional oil and gas reservoir core sample under uniaxial compression or triaxial compression according to the stress-strain data; A second determination module is used to determine the pre-peak total energy of the target unconventional oil and gas reservoir core sample based on the peak strain; The third determination module is used to determine the rock brittleness value of the target unconventional oil and gas reservoir based on the peak strain and the pre-peak total energy.

8. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, the method for evaluating the brittleness of unconventional oil and gas reservoirs according to any one of claims 1 to 6 is implemented.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the method for evaluating the brittleness of unconventional oil and gas reservoirs as described in any one of claims 1 to 6 is implemented.

10. A computer program product comprising a computer program / instructions, characterized in that When the computer program / instruction is executed by a processor, the steps in the unconventional oil and gas reservoir brittleness evaluation method described in any one of claims 1 to 6 are implemented.

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