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

Abstract

The embodiment of the present application provides a kind of unconventional oil and gas reservoir brittleness evaluation method, device, equipment, medium and product, it is related to unconventional oil and gas reservoir exploration and development technical field.Aiming at the problem that the brittleness evaluation of current unconventional oil and gas reservoir is not well matched with reservoir reconstruction effect, a brittleness evaluation method according to reservoir rock failure energy and deformation behavior is proposed to realize the quick and accurate evaluation of reservoir rock brittleness, and provide theoretical guidance for the selection of fracturing target reservoir and fracturing scheme design.The present application uses the basic principle that the greater the rock brittleness, the smaller the energy consumed by the rock under uniaxial / triaxial compression and the smaller the rock deformation, combines the uniaxial / triaxial compression failure energy of rock with the deformation of rock at the time of failure, obtains the compression failure energy and deformation parameters of rock using the stress-strain curve of rock, and evaluates the brittleness of reservoir rock by the deformation size under unit energy when rock fails.

Description

TECHNICAL FIELD

[0001] The embodiment of the present application relates to the technical field of unconventional oil and gas reservoir exploration and development, and particularly relates to a method, device, equipment, medium and product for evaluating the brittleness of an unconventional oil and gas reservoir. BACKGROUND

[0002] The geological features of an unconventional oil and gas reservoir are complex, and it is difficult to accurately predict geological sweet spots and engineering sweet spots. When the unconventional oil and gas reservoir is fractured and modified, the brittleness evaluation of the reservoir rock is of great significance to the selection of a fracturing section, fracturing construction design, fracture network modification volume and oil and gas production evaluation. At present, the brittleness of the reservoir rock is mainly evaluated by means of logging, seismic inversion, indoor rock mechanics experiment and the like. However, the brittleness index evaluation method is not good at matching the brittleness evaluation result of the reservoir rock with the fracturing modification effect of the unconventional reservoir, and the accuracy of the field application is not high.

[0003] Therefore, it is urgent to establish a rock brittleness calculation method which can accurately evaluate the brittleness of the reservoir rock and match the rock brittleness with the fracturing modification volume of the reservoir. SUMMARY

[0004] The embodiment of the present application provides a method, device, equipment, medium and product for evaluating the brittleness of an unconventional oil and gas reservoir to at least partially solve the above problems.

[0005] The first aspect of the embodiment of the present application provides a method for evaluating the brittleness of an unconventional oil and gas reservoir, and the method comprises the following steps.

[0006] Stress-strain data obtained by a target unconventional oil and gas reservoir core sample in a uniaxial compression or triaxial compression test is acquired;

[0007] The peak strain of the target unconventional oil and gas reservoir core sample under uniaxial compression or triaxial compression is determined according to the stress-strain data;

[0008] The total pre-peak energy of the target unconventional oil and gas reservoir core sample is determined based on the peak strain;

[0009] The rock brittleness value of the target unconventional oil and gas reservoir is determined based on the peak strain and the total pre-peak energy. Optionally, the stress-strain data obtained by the target unconventional oil and gas reservoir core sample in the uniaxial compression or triaxial compression test comprises the following steps.

[0010] Stress-strain data obtained by a plurality of fracturing sections of a target unconventional oil and gas reservoir core sample in a uniaxial or triaxial compression test is acquired;

[0011] The rock brittleness value of the target unconventional oil and gas reservoir is determined according to the stress-strain data, and the method comprises the following steps.

[0012] According to stress-strain data of each core sample of the multiple fracturing sections, a rock brittleness value of each of the multiple fracturing sections is obtained;

[0013] The method further comprises:

[0014] The rock brittleness values of the multiple fracturing sections are compared, and a fracturing section with a maximum rock brittleness value is determined as a target fracturing section;

[0015] Based on the target fracturing section, an engineering sweet spot selection suggestion of the target unconventional oil and gas reservoir is output.

[0016] Optionally, stress-strain data obtained in a uniaxial compression or triaxial compression test of a core sample of the target unconventional oil and gas reservoir is acquired, including:

[0017] The stress-strain data obtained in a uniaxial or triaxial compression test of the core sample of the target unconventional oil and gas reservoir under different environmental conditions is acquired, and the environmental conditions include confining pressure conditions, temperature conditions and / or fluid conditions;

[0018] According to the stress-strain data, a rock brittleness value of the target unconventional oil and gas reservoir is determined, including:

[0019] According to the stress-strain data obtained under each environmental condition, a rock brittleness value of the target unconventional oil and gas reservoir under each environmental condition is determined;

[0020] The method further comprises:

[0021] According to the rock brittleness values of the target unconventional oil and gas reservoir under each environmental condition, a brittleness evolution rule of the target unconventional oil and gas reservoir with changes in environmental conditions is obtained;

[0022] Based on the brittleness evolution rule, an engineering sweet spot selection suggestion of the target unconventional oil and gas reservoir is output.

[0023] Optionally, based on the peak strain, a total pre-peak energy of the core sample of the target unconventional oil and gas reservoir is determined, including:

[0024] The stress-strain curve in the range of an initial strain 0 to a peak strain is integrated to obtain a total pre-peak energy of the core sample : .

[0025] Optionally, based on the peak strain and the total pre-peak energy, a rock brittleness value is determined, including: a rock brittleness value is determined based on the following formula:

[0026] ;

[0027] wherein,BI represents a rock brittleness value.

[0028] Optionally, the stress-strain data is determined by the following steps:

[0029] Drilling a core from a target unconventional oil and gas reservoir, and processing the core into a cylindrical test sample;

[0030] Performing a uniaxial or triaxial compression test on the cylindrical test sample, to obtain stress-strain data of the core sample of the target unconventional oil and gas reservoir obtained in the uniaxial or triaxial compression test;

[0031] wherein, during the uniaxial or triaxial compression test, the stress loading rate is less than 0.05 mm / min.

[0032] The second aspect of the embodiment of the present application provides an unconventional oil and gas reservoir brittleness evaluation device, which comprises:

[0033] an acquisition module configured to acquire stress-strain data of a core sample of a target unconventional oil and gas reservoir obtained in a uniaxial or triaxial compression test;

[0034] a first determination module configured to determine a peak strain of the core sample of the target unconventional oil and gas reservoir under uniaxial or triaxial compression according to the stress-strain data;

[0035] a second determination module configured to determine a total pre-peak energy of the core sample of the target unconventional oil and gas reservoir based on the peak strain;

[0036] a third determination module configured to determine a rock brittleness value of the target unconventional oil and gas reservoir based on the peak strain and the total pre-peak energy.

[0037] The third aspect of the embodiment of the present application provides an electronic device, which comprises a memory, a processor, and a computer program stored in the memory and executable on the processor, and the processor implements the unconventional oil and gas reservoir brittleness evaluation method of the first aspect of the present application when executed.

[0038] The fourth aspect of the embodiment of the present application provides a computer readable storage medium, which stores a computer program, and the program implements the unconventional oil and gas reservoir brittleness evaluation method of the first aspect of the present application when executed by a processor.

[0039] The fifth aspect of the embodiment of the present application provides a computer program product, which comprises a computer program / instruction, and the computer program / instruction implements the steps of the unconventional oil and gas reservoir brittleness evaluation method of the first aspect of the present application when executed by a processor.

[0040] In the embodiment of the present application, in view of the problem that the current unconventional oil and gas reservoir brittleness evaluation and reservoir reconstruction effect are not well matched, an unconventional oil and gas reservoir brittleness evaluation method is provided, which is based on the relationship between the damage energy and deformation behavior of unconventional oil and gas reservoir rocks to evaluate the brittleness of unconventional oil and gas reservoirs, so as to realize rapid and accurate evaluation of the brittleness of reservoir rocks and provide theoretical guidance for selecting and designing fracturing schemes for target reservoirs. The energy required for rock failure and deformation is a direct manifestation of rock brittleness. The unconventional oil and gas reservoir rock brittleness index calculation method provided by the present application uses the basic principle that the greater the rock brittleness, the smaller the energy consumed by the rock under uniaxial / three-axial compression and the smaller the rock deformation. The uniaxial / three-axial compression damage energy and deformation of the rock at the time of failure are combined, the compression damage 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 by the deformation size under unit energy at the time of rock failure. BRIEF DESCRIPTION OF DRAWINGS

[0041] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the description of the embodiments of the present application. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0042] Figure 1 is a step flow chart of the unconventional oil and gas reservoir brittleness evaluation method provided by the embodiment of the present application;

[0043] Figure 2 is a rock mechanics test sample configuration in the unconventional oil and gas reservoir brittleness evaluation method provided by the embodiment of the present application;

[0044] Figure 3 is a schematic diagram of the stress-strain curve and the total energy before the peak of uniaxial compression or triaxial compression in the unconventional oil and gas reservoir brittleness evaluation method provided by the embodiment of the present application; U p , the peak strain at the time of failure ( ε p );

[0045] Figure 4 is a graph of the unconventional reservoir rock brittleness index calculated in the unconventional oil and gas reservoir brittleness evaluation method provided by the embodiment of the present application;

[0046] Figure 5 is a stress-strain curve graph of a shale core under different confining pressures in the unconventional oil and gas reservoir brittleness evaluation method provided by the embodiment of the present application;

[0047] Figure 6It is the evaluation result figure of shale brittleness under different confining pressures in the unconventional oil and gas reservoir brittleness evaluation method provided by the embodiment of the present application.

[0048] Figure 7 It is the rock brittleness evaluation effect figure of different unconventional oil and gas reservoirs in the engineering in the unconventional oil and gas reservoir brittleness evaluation method provided by the embodiment of the present application.

[0049] Figure 8 It is the typical fracturing curve of hydraulic fracturing in case 2 provided by the embodiment of the present application, which shows the real-time data of injection pressure and displacement in the fracturing process.

[0050] Figure 9 It is the pressure power curve in case 2 provided by the embodiment of the present application, and the fracturing power is determined by the injection pressure and displacement.

[0051] Figure 10 It is the relationship between the reservoir rock brittleness and the unit reservoir reconstruction volume fracturing energy of different well sections of unconventional oil and gas in different regions in the engineering obtained in the unconventional oil and gas reservoir brittleness evaluation method provided by the embodiment of the present application. DETAILED DESCRIPTION

[0052] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the present application will be further described in detail below with reference to the drawings and specific embodiments.

[0053] Firstly, the professional terms related to the embodiment of the present application are explained:

[0054] Geological dessert: In oil and gas exploration and development, geological dessert refers to an area or interval that is rich in oil and gas and can be effectively developed under current economic and technical conditions. Specifically, geological dessert includes the following aspects: physical property dessert: This refers to an area or interval in a tight oil reservoir that has relatively high porosity and permeability compared to the overall tight background. Reservoir dessert: This refers to an area or interval with relatively high oil saturation, relatively light oil quality (relatively low density and viscosity), relatively high pressure state (pressure coefficient greater than 1), and relatively high reserve abundance in a low-abundance oil-bearing background. Physical property dessert and reservoir dessert are collectively referred to as geological dessert, which is a region or interval that is relatively concentrated and rich in tight oil from a geological perspective. Geological dessert determines the resource potential of tight oil, while engineering dessert determines the development effect of tight oil. The identification and evaluation of geological dessert have important guiding significance for oil and gas exploration and development, and can help determine the area most likely to obtain high yield, thereby optimizing exploration and development strategies.

[0055] Engineering sweet spot: In engineering, especially in the field of oil and gas geology, it refers to the place where the oil and gas reservoir is easy to develop by fracturing on the basis of the geological sweet spot. In oil and gas exploration and development, "engineering sweet spot" and "geological sweet spot" together constitute the so-called "double sweet spot". The geological sweet spot refers to the area where the oil and gas reservoir is rich, and the engineering sweet spot refers to the place where the oil and gas reservoir is easy to develop by fracturing. In practical application, the prediction of engineering sweet spot usually depends on two means of logging and seismic exploration. Through these technical means, the geological parameters of well point can be finely evaluated, and the distribution of core parameters (such as porosity, permeability and brittleness) can be evaluated.

[0056] Unconventional oil and gas reservoir: unconventional oil and gas refers to the oil and gas resources that cannot obtain natural industrial yield by using traditional technology, and need to use new technology to improve the permeability of reservoir or the viscosity of fluid, etc. so as to be economically exploited. The reservoir is the rock formation of the formation which can store and seep fluid. Therefore, the unconventional oil and gas reservoir refers to the rock formation of the formation which can store and seep unconventional oil and gas resources.

[0057] The embodiment of the present application provides a step flow chart of a method for evaluating the brittleness of unconventional oil and gas reservoir, as shown in Figure 1 The method for evaluating the brittleness of unconventional oil and gas reservoir comprises the following steps:

[0058] S101, obtaining stress-strain data of a target unconventional oil and gas reservoir core sample obtained in a uniaxial compression or triaxial compression test;

[0059] 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;

[0060] S103, determining the total energy before the peak of the target unconventional oil and gas reservoir core sample based on the peak strain;

[0061] S104, determining the rock brittleness value of the target unconventional oil and gas reservoir based on the peak strain and the total energy before the peak.

[0062] In the step S102, the stress-strain curve of the rock sample can be analyzed to obtain the peak strain under uniaxial / triaxial compression (σ ), and specifically, the maximum strain point in the stress-strain curve can be taken as the peak strain.

[0063] In the embodiment of the present application, the area under the compression stress-strain curve represents the work done by the external force on the rock, and also represents the required energy in the whole process from loading to rock failure. Therefore, the total energy before the peak can be determined based on the area under the stress-strain curve and the peak strain.

[0064] The energy required for rock failure and deformation behavior is a direct embodiment of rock brittleness. The unconventional oil and gas reservoir rock brittleness index calculation method provided in the present application uses the basic principle that the greater the rock brittleness, the smaller the energy consumed by the rock under uniaxial / triaxial compression conditions and the smaller the rock deformation. The uniaxial / triaxial compression failure energy of the rock is combined with the deformation of the rock at the time of failure, the compression failure energy and the 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 by the deformation size under unit energy at the time of rock failure.

[0065] In the embodiment of the present application, the following steps can be used to determine the stress-strain data:

[0066] S100, drilling and coring the target unconventional oil and gas reservoir to process the obtained core into a cylindrical test sample;

[0067] S200, performing uniaxial or triaxial compression test on the cylindrical test sample to obtain the stress-strain data of the core sample of the target unconventional oil and gas reservoir obtained in the uniaxial or triaxial compression test.

[0068] In the embodiment of the present application, the preparation process of the test sample includes: drilling and coring the target unconventional oil and gas reservoir to process the obtained core into a cylindrical test sample.

[0069] In the embodiment of the present application, the in-situ environmental parameters of the reservoir such as in-situ stress characteristics (for example, confining pressure) and temperature, fluid, etc. can also be obtained.

[0070] In the embodiment of the present application, the reservoir rock compression failure experiment process includes: performing uniaxial compression test or triaxial compression test on the test sample in the above step, and under the condition that the condition is allowed, triaxial compression test under the in-situ environmental condition of the reservoir can also be performed, the stress-strain data of the reservoir core under uniaxial compression or triaxial compression condition is obtained, and the stress-strain curve is drawn.

[0071] In the embodiment of the present application, in the actual application process, the target unconventional oil and gas reservoir can be drilled and cored, and the obtained core can be processed into a cylinder with a diameter of 50 mm and a height of 100 mm or a diameter of 25 mm and a height of 50 mm. The in-situ stress characteristics and temperature parameters of the reservoir under the in-situ environmental condition are obtained.

[0072] Specifically, in the embodiment of the present application, the sample configuration of the prepared rock mechanics test (uniaxial compression test or triaxial compression test) is as shown in Figure 2 .

[0073] In the actual application process, the uniaxial or triaxial compression test can be carried out for the core sample, the triaxial compression test under the reservoir temperature and pressure condition can be carried out when the condition permits, the loading rate must meet the quasi-static loading requirement of the rock, and the recommended loading rate is less than 0.05 mm / min, and the compression stress-strain curve of the reservoir core under the uniaxial / triaxial condition is obtained.

[0074] In an alternative embodiment, the step S103 comprises: integrating the stress-strain curve in the range of initial strain 0 to peak strain to obtain the total pre-peak energy of the rock sample :

[0075] (1)

[0076] In the uniaxial compression test or triaxial compression test, the load and the deformation data of the rock sample are obtained, and then the stress σ and strain ε of the rock are calculated. Further analysis of the stress-strain curve of the rock sample obtains the peak strain under uniaxial compression or triaxial compression.

[0077] In the embodiment of the application, the total pre-peak energy is determined based on the area of the stress-strain curve at the peak strain, and specifically, the stress-strain curve in the range of initial strain 0 to peak strain is integrated to obtain the total pre-peak energy of the rock sample.

[0078] In the 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 the total pre-peak energy of the rock sample at the time of failure. For example, the stress-strain curve of the rock under uniaxial or triaxial loading, the total pre-peak energy , and the peak strain at the time of failure are shown in the schematic diagram as Figure 3 .

[0079] In an alternative embodiment, the step S104:

[0080] The rock brittleness value is determined based on the following formula:

[0081] (2)

[0082] wherein, BI represents the rock brittleness value.

[0083] 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. Based on the rock brittleness value, the brittleness differences of unconventional reservoir rocks can be compared.

[0084] 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 is ( 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.

[0085] In an optional embodiment, the unconventional oil and gas reservoir brittleness assessment method comprises the following steps:

[0086] S201, obtaining stress-strain data of core samples of multiple fractured sections of a target unconventional oil and gas reservoir obtained in a uniaxial or triaxial compression test;

[0087] S202, obtaining rock brittleness values ​​of the multiple fracturing sections based on stress-strain data of the core samples of the multiple fracturing sections;

[0088] S203, comparing the rock brittleness values ​​of the multiple fracturing stages, and determining the fracturing stage with the largest rock brittleness value as the target fracturing stage;

[0089] S204: Outputting an engineering sweet spot selection suggestion for the target unconventional oil and gas reservoir based on the target fracturing stage.

[0090] Based on the method provided in the embodiments of the present invention, in practical applications, by comparing the brittleness values ​​corresponding to cores from different regions, different fracturing sections, or different fracturing wells, the differences in reservoir rock brittleness in different regions / fracturing wells / fracturing sections can be determined, thereby guiding engineering embodiments to select fracturing target sections based on the brittleness of different rocks, and further guiding the selection of engineering sweet spots.

[0091] In an optional embodiment, the unconventional oil and gas reservoir brittleness assessment method comprises the following steps:

[0092] S301, obtaining stress-strain data of a target unconventional oil and gas reservoir core sample obtained from a uniaxial or triaxial compression test under different environmental conditions, wherein the environmental conditions include: confining pressure conditions, temperature conditions, and / or fluid conditions;

[0093] S302, determining rock brittleness values of the target unconventional oil and gas reservoir under various environmental conditions according to stress-strain data obtained under various environmental conditions;

[0094] S303, obtaining a brittleness evolution rule of the target unconventional oil and gas reservoir with the change of environmental conditions according to the rock brittleness values of the target unconventional oil and gas reservoir under various environmental conditions;

[0095] S304, outputting an engineering sweet spot selection suggestion of the target unconventional oil and gas reservoir based on the brittleness evolution rule.

[0096] In the embodiment of the present application, triaxial compression mechanics test can be used to apply temperature, pressure, fluid and other environmental variables under in-situ reservoir environment to evaluate the brittleness of reservoir rock under in-situ environmental conditions. In the embodiment of the present application, the confining pressure, temperature and fluid conditions can be changed during the mechanics test to predict the brittleness evolution rule of the reservoir rock with the change of environmental variables.

[0097] Further, the engineering sweet spot selection suggestion can be outputted based on the brittleness evolution rule and actual engineering requirements. Specifically, after evaluating the rock brittleness of different reservoir locations by the brittleness evaluation method provided in the embodiment of the present application, the place with more brittle reservoir rock is more beneficial to be selected as an engineering sweet spot.

[0098] In order to prove the effectiveness of the method provided in the embodiment of the present application, the present application provides the following specific implementation cases to verify the method provided in the embodiment of the present application.

[0099] Case 1: Brittle evaluation of reservoir rock under different reservoir confining pressures.

[0100] In this case, the shale core in the shale gas reservoir of a certain area in Sichuan is processed into a cylinder with a diameter of 25 mm and a height of 50 mm. Uniaxial compression test of the core under no confining pressure condition and triaxial compression test under 20 MPa, 40 MPa and 70 MPa conditions are carried out. The compression stress-strain curves of the reservoir rock under different confining pressures are obtained, as shown in Figure 5 .

[0101] The physical and mechanical parameters of the shale under different confining pressures are calculated according to the stress-strain curve. The brittleness index of the shale under different confining pressures is calculated by the brittleness index calculation formula of the present application. Details are shown in Table 1 below. The relationship between the brittleness parameters of the shale under different confining pressures and the confining pressure is shown in Figure 6 . With the increase of the confining pressure, the brittleness of the shale gradually decreases, indicating that the method provided in the embodiment of the present application can accurately predict the influence of the confining pressure on the brittleness of the reservoir rock.

[0102] Table 1 Elastic physical parameters and brittleness values of shale under different confining pressures

[0103]

[0104] Case 2: The relationship between the reservoir rock brittleness evaluation of different fracturing well sections and the fracturing energy of unit reservoir reconstruction volume.

[0105] In this case, after the cores of different well sections of unconventional oil and gas reservoirs (tight gas and shale gas) are collected, the cores are processed into cylinders with a diameter of 25 mm and a height of 50 mm, and triaxial compression tests of the cores under the corresponding reservoir surrounding conditions without confining pressure are carried out, and the stress-strain curves of different reservoir rocks are obtained, and then the brittleness index of different reservoir rocks is calculated by using the method provided in the present application, as shown in the following formula. Figure 7 The typical hydraulic fracturing curve is shown in the following figure. Figure 8 The figure shows the real-time data of the injection pressure and the displacement during the fracturing process, and further shows the relationship between the injection pressure and the displacement with time, and the injection pressure multiplied by the displacement obtains the fracturing power curve as shown in the following figure. Figure 9 The fracturing power is determined by the injection pressure and the displacement. The total fracturing energy of the well section is obtained by numerically integrating the fracturing power curve over the entire fracturing construction time. The total fracturing energy of different well sections and the total reconstruction volume in this case are shown in Table 2. The total fracturing energy is divided by the fracturing reservoir reconstruction volume (SRV) of the corresponding well section to obtain the fracturing energy required for the reconstruction of unit SRV. The relationship between the brittleness (BI) of different well section reservoir rocks and the fracturing energy required for unit SRV is shown in the following figure. Figure 10 Figure 10 It is illustrated that the greater the brittleness index of the reservoir rock, the more brittle the reservoir rock, and the more brittle the reservoir rock, the easier it is to be fractured, and the smaller the energy required for the reconstruction of unit SRV. Figure 10 It is also proved that the reservoir rock brittleness evaluation method provided in the present application has engineering applicability and great accuracy.

[0106] Table 2 Total fracturing energy and total reconstruction volume of different fracturing well sections

[0107]

[0108] Therefore, in the present application, based on the real field construction data, the engineering applicability of the brittleness evaluation method proposed in the present application is verified.

[0109] In the present application, it is suggested that 3-5 cores are used for rock mechanics test.

[0110] Further, in the present application, the fracturing energy required for the reconstruction of unit SRV can be determined based on the peak total energy of the target unconventional oil and gas reservoir, and the total fracturing energy of the fracturing reservoir reconstruction volume of the well section corresponding to the target unconventional oil and gas reservoir is further determined, and the suggestions on the injection pressure and the displacement in engineering are further output. ​

[0111] Based on the same inventive concept, the embodiments of the present application also provide a device for evaluating the brittleness of a non-conventional oil and gas reservoir, which comprises:

[0112] an acquisition module, configured to acquire stress-strain data of a target non-conventional oil and gas reservoir core sample obtained in a uniaxial compression or triaxial compression test;

[0113] a first determination module, configured to determine a peak strain of the target non-conventional oil and gas reservoir core sample under uniaxial compression or triaxial compression according to the stress-strain data;

[0114] a second determination module, configured to determine a total pre-peak energy of the target non-conventional oil and gas reservoir core sample based on the peak strain;

[0115] a third determination module, configured to determine a rock brittleness value of the target non-conventional oil and gas reservoir based on the peak strain and the total pre-peak energy.

[0116] Optionally, the acquisition module is specifically configured to acquire stress-strain data of core samples of multiple fracturing sections of a target non-conventional oil and gas reservoir obtained in a uniaxial or triaxial compression test;

[0117] The third determination module is specifically configured to obtain a 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 respectively;

[0118] The device further comprises:

[0119] a comparison module, configured to compare the rock brittleness values of the multiple fracturing sections respectively, and determine a fracturing section with the largest rock brittleness value as a target fracturing section;

[0120] an output module, configured to output an engineering sweet spot selection suggestion of the target non-conventional oil and gas reservoir based on the target fracturing section.

[0121] Optionally, the acquisition module is specifically configured to acquire stress-strain data of a target non-conventional 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;

[0122] The third determination module is specifically configured to determine a rock brittleness value of the target non-conventional oil and gas reservoir under each of the environmental conditions according to the stress-strain data obtained under each of the environmental conditions;

[0123] The device further comprises:

[0124] The analysis module is configured to obtain a brittleness evolution rule of the target unconventional oil and gas reservoir with the change of environmental conditions according to the rock brittleness values of the target unconventional oil and gas reservoir under various environmental conditions.

[0125] The output module is configured to output an engineering sweet spot selection suggestion of the target unconventional oil and gas reservoir based on the brittleness evolution rule.

[0126] Optionally, the second determination module is specifically configured to:

[0127] integrate the stress-strain curve in the initial strain 0 to the peak strain to obtain the total pre-peak energy of the rock sample : .

[0128] Optionally, the third determination module is specifically configured to:

[0129] determine the rock brittleness value based on the following formula:

[0130] ;

[0131] wherein, BI represents the rock brittleness value.

[0132] Optionally, the stress-strain data is determined by the following steps:

[0133] drilling and coring the target unconventional oil and gas reservoir to obtain a cylindrical test sample from the rock core;

[0134] performing uniaxial or triaxial compression test on the cylindrical test sample to obtain stress-strain data of the core sample of the target unconventional oil and gas reservoir obtained in the uniaxial or triaxial compression test;

[0135] wherein, during the uniaxial or triaxial compression test, the stress loading rate is less than 0.05 mm / min.

[0136] Based on the same inventive concept, the embodiments of the present application also provide an electronic device, which comprises a memory, a processor and a computer program stored in the memory and executable on the processor, and the processor implements the steps in the unconventional oil and gas reservoir brittleness evaluation method according to any one of the above embodiments when executed.

[0137] Based on the same inventive concept, the embodiments of the present application also provide a computer readable storage medium having a computer program stored thereon, and the program is executed by a processor to implement the steps in the unconventional oil and gas reservoir brittleness evaluation method according to any one of the above embodiments.

[0138] Based on the same inventive concept, the embodiments of the present application provide a computer program product comprising computer programs / instructions which, when executed by a processor, implement the steps of the unconventional oil and gas reservoir brittleness evaluation method described in any of the above embodiments.

[0139] Each of the embodiments in the present specification is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other.

[0140] Those skilled in the art should understand that the embodiments of the present application can be provided as a method, device, or computer program product. Therefore, the embodiments of the present application can take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware aspects. Moreover, the embodiments of the present application can 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 code.

[0141] The embodiments of the present application are described with reference to flowcharts and / or block diagrams of the method, terminal device (apparatus), and computer program product according to the embodiments of the present application. It should be understood that each flow and / or block in the flowcharts and / or block diagrams, and the combination of flows and / or blocks in the flowcharts and / or block diagrams can be implemented by computer program instructions. These computer program instructions can be provided to a general-purpose computer, special-purpose computer, embedded processor, or other programmable terminal device to produce a machine, so that the instructions executed by the computer or other programmable terminal device produce the functions specified in the flowcharts and / or block diagrams. Figure 1 one or more flows and / or blocks Figure 1 an apparatus that performs the functions specified in one or more blocks.

[0142] These computer program instructions can also be stored in a computer-readable memory that can direct the computer or other programmable terminal device to work in a specific manner, so that the instructions stored in the computer-readable memory produce a manufactured product including instruction apparatus, which implements the functions specified in the flowcharts and / or block diagrams. Figure 1 one or more flows and / or blocks Figure 1 an apparatus that performs the functions specified in one or more blocks.

[0143] These computer program instructions can also be loaded into a computer or other programmable terminal device, so that a series of operation steps are performed on the computer or other programmable terminal device to produce a computer-implemented process, so that the instructions executed on the computer or other programmable terminal device provide a process for implementing the functions specified in the flowcharts and / or block diagrams. Figure 1 one or more flows and / or blocks Figure 1steps of a method, operations of an apparatus, or computer functions implemented by a processor.

[0144] While the preferred embodiments of the application have been described above, it should be understood that many modifications and variations to these embodiments will be apparent to those skilled in the art once they learn of the basic inventive concepts. Therefore, the attached claims are intended to cover all such modifications and variations.

[0145] Finally, it is to be understood that the phraseology or terminology employed herein, such as "first" and "second", etc., are for descriptive purposes only and should not be construed to be limiting unless otherwise indicated. Moreover, the use of "including", "comprising", or "having" and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. Unless otherwise indicated, the use of "or" is to be interpreted as inclusive so that "A or B" means "A or B or both". Unless otherwise indicated, the use of conjunctive language such as the phrase "at least one of" is to be understood to allow for zero instances of the conjunctive phrase so that, for this example, "at least one of A and B" means "B only".

[0146] The unconventional oil and gas reservoir brittleness evaluation method provided by the present application is described in detail above, and the principles and implementation manners of the present application are described by using specific examples in the present application. The above description of the embodiments is only used to help understand the method of the present application and the core idea thereof; meanwhile, for those skilled in the art, according to the idea of the present application, the specific implementation manners and application ranges will be changed, and the above description should not be understood as a limitation of the present application.

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 from uniaxial compression or triaxial compression tests; determining the peak strain of the target unconventional oil and gas reservoir core sample under uniaxial compression or triaxial compression based on the stress-strain data; determining the total pre-peak energy of the target unconventional oil and gas reservoir core sample based on the peak strain; Determining the rock brittleness value of the target unconventional oil and gas reservoir 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, represents the peak strain at rock sample failure, Represents the total pre-peak energy of the rock sample.

2. The unconventional oil and gas reservoir brittleness evaluation method according to claim 1, characterized in that: Obtain stress-strain data from uniaxial or triaxial compression tests on target unconventional oil and gas reservoir core samples, including: Obtain stress-strain data from core samples of multiple fracture stages in target unconventional oil and gas reservoirs during uniaxial or triaxial compression tests; Determining the rock brittleness value of the target unconventional oil and gas reservoir based on 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 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 from uniaxial or triaxial compression tests on target unconventional oil and gas reservoir core samples, including: Obtaining stress-strain data of a target unconventional oil and gas reservoir core sample obtained from 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 based on 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 values ​​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, an engineering sweet spot selection suggestion 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 method for evaluating the brittleness of unconventional oil and gas reservoirs according to any one of claims 1 to 4, characterized in that: The stress-strain data are determined using the following steps: Drilling and coring the target unconventional oil and gas reservoirs, and processing the cores into cylindrical test samples; 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; Wherein, during the uniaxial or triaxial compression test, the stress loading rate is less than 0.05 mm / min.

6. 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 is used to obtain 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 configured to determine the peak strain of a target unconventional oil and gas reservoir core sample under uniaxial compression or triaxial compression based on the stress-strain data; a second determining module, configured 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 configured 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, including: determining the rock brittleness value based on the following formula: ； in, BI Indicates the rock brittleness value, represents the peak strain at rock sample failure, Represents the total pre-peak energy of the rock sample.

7. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein: 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 5 is implemented.

8. 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 according to any one of claims 1 to 5 is implemented.

9. A computer program product comprising a computer program / instructions, characterized in that When the computer program / instruction is executed by a processor, the steps of the unconventional oil and gas reservoir brittleness evaluation method according to any one of claims 1 to 5 are implemented.

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