Unconventional reservoir fracture opening degree calculation method and device, medium and electronic equipment

Abstract

The invention discloses an unconventional reservoir fracture opening degree calculation method and device, a medium and electronic equipment. The method comprises the following steps: carrying out nuclear magnetic resonance rock core test on a rock core sample to obtain the relaxation rate and relaxation signal amplitude of the rock core sample, so as to obtain a nuclear magnetic resonance T2 spectrum of the rock core sample according to the relaxation rate and the relaxation signal amplitude; performing a pressure pump test on the rock core sample to obtain pore throat radius distribution of the rock core sample; determining a conversion coefficient between the nuclear magnetic resonance T2 spectrum and the pore throat radius distribution by analyzing the nuclear magnetic resonance T2 spectrum and the pore throat radius distribution; and determining the fracture opening of the unconventional reservoir based on the nuclear magnetic resonance T2 spectrum and the conversion coefficient. According to the technical scheme provided by the invention, the accuracy of calculating the fracture opening of the unconventional reservoir can be improved.

Description

Technical Field

[0001] The present application belongs to the field of petroleum exploration technology, and in particular relates to a method, device, medium and electronic equipment for calculating the aperture of unconventional reservoir fractures. Background Art

[0002] Nuclear magnetic resonance core analysis technology is a new method for studying reservoir pore throat characteristics in the field of oil exploration and development. It has developed rapidly in recent years and has been widely used in the industry. It can obtain capillary pressure information to evaluate rock pore throat characteristics. It has the advantages of fast testing speed, simple operation, simple data processing, and high measurement accuracy. At the same time, it can continuously test rock samples without damaging the core. Nuclear magnetic resonance technology has great advantages in the quantitative characterization of microscopic pore throats. Since the porosity and permeability in tight reservoirs are very poor, the development of fractures in tight reservoirs is one of the focuses of our research. How to quantitatively identify the fracture aperture in tight reservoirs has always been an important problem that has troubled us.

[0003] At present, there is little research on this aspect at home and abroad. Therefore, this application provides a method for calculating the aperture of unconventional reservoir fractures to improve the accuracy of calculating the aperture of unconventional reservoir fractures, and can provide important technical support and theoretical basis for the evaluation of unconventional reservoirs and unconventional development in the later stage. Summary of the invention

[0004] The embodiments of the present application provide a method, device, medium and electronic device for calculating the aperture of unconventional reservoir fractures. The method can improve the accuracy of calculating the aperture of unconventional reservoir fractures and provide important technical support and theoretical basis for the subsequent evaluation of unconventional reservoirs and unconventional development.

[0005] Other features and advantages of the present application will become apparent from the following detailed description, or may be learned in part by the practice of the present application.

[0006] According to a first aspect of an embodiment of the present application, a method for calculating the fracture aperture of an unconventional reservoir is provided, characterized in that the method comprises: obtaining a relaxation rate and a relaxation signal amplitude of the core sample by performing a nuclear magnetic resonance core test on a core sample, thereby obtaining a nuclear magnetic resonance T2 spectrum of the core sample based on the relaxation rate and the relaxation signal amplitude; obtaining a pore throat radius distribution of the core sample by performing a pressure pump test on the core sample; determining a conversion coefficient between the nuclear magnetic resonance T2 spectrum and the pore throat radius distribution by analyzing the nuclear magnetic resonance T2 spectrum and the pore throat radius distribution; and determining the fracture aperture of the unconventional reservoir based on the nuclear magnetic resonance T2 spectrum and the conversion coefficient.

[0007] In some embodiments of the present application, based on the aforementioned scheme, after obtaining the nuclear magnetic resonance T2 spectrum of the core sample according to the relaxation rate and the relaxation signal amplitude, the method also includes: determining a spin echo train calculation formula according to the relaxation rate and the relaxation signal amplitude; performing multi-exponential fitting on the spin echo train corresponding to the relaxation rate and the relaxation signal amplitude based on the spin echo train calculation formula to obtain a relaxation time distribution curve of the nuclear magnetic resonance T2 spectrum, thereby determining the fracture aperture of the unconventional reservoir.

[0008] In some embodiments of the present application, based on the above scheme, the spin echo train is determined as follows:

[0009]

[0010] Among them, E cho (t) is the echo amplitude at time t, T 2i is the transverse relaxation time of the ith component, Φ i is the NMR pore size of the ith component.

[0011] In some embodiments of the present application, based on the aforementioned scheme, determining the fracture aperture of the unconventional reservoir based on the nuclear magnetic resonance T2 spectrum and the conversion coefficient includes: determining the fracture type in the unconventional reservoir according to the nuclear magnetic resonance T2 spectrum, the fracture types including trapezoidal fractures, wedge-shaped fractures, and parallel fractures; obtaining the fracture frequency of the fractures in the unconventional reservoir according to the nuclear magnetic resonance T2 spectrum, the fracture frequency characterizing the number or width of fractures per unit length or unit area; determining the fracture aperture of the unconventional reservoir based on the nuclear magnetic resonance T2 spectrum, the conversion coefficient, the fracture type, and the fracture frequency.

[0012] In some embodiments of the present application, based on the aforementioned scheme, in the process of determining the fracture aperture of the unconventional reservoir based on the nuclear magnetic resonance T2 spectrum, the conversion factor, the fracture type, and the fracture frequency, the method also includes: using the mercury injection nuclear magnetic conversion method to characterize the nuclear magnetic resonance T2 spectrum using rock surface relaxation, fluid relaxation, and molecular diffusion relaxation; analyzing the relationship between the rock surface relaxation and the rock surface ratio, and using the rock surface ratio to characterize the rock surface relaxation; combining the rock surface relaxation and the rock surface ratio, and determining the fracture aperture of the unconventional reservoir based on the nuclear magnetic resonance T2 spectrum, the conversion factor, the fracture type, and the fracture frequency.

[0013] In some embodiments of the present application, based on the above scheme, the nuclear magnetic resonance T2 spectrum is characterized by the following formula:

[0014]

[0015] in, is the nuclear magnetic resonance T2 spectrum, For rock surface relaxation, is the fluid relaxation, is molecular diffusion relaxation.

[0016] In some embodiments of the present application, based on the above scheme, the rock surface relaxation is characterized by the following formula:

[0017]

[0018] in, For rock surface relaxation, is the rock surface ratio, and ρ2 is the relaxation rate.

[0019] In some embodiments of the present application, based on the aforementioned scheme, before determining the fracture aperture of the unconventional reservoir based on the nuclear magnetic resonance T2 spectrum, the conversion coefficient, the fracture type, and the fracture frequency, the method further includes: calculating the fracture surface area and the fracture volume according to the fracture type, thereby obtaining the rock specific surface area, and the rock specific surface area characterizes the ratio of the pore surface area or the fracture surface area in the rock to the pore volume or the fracture volume.

[0020] In some embodiments of the present application, based on the above solution, when the crack type is a trapezoidal crack, the crack surface area is calculated by the following formula:

[0021]

[0022] Where S is the crack surface area, w f is the crack opening, Lf is the crack length, h f is the crack width, wf1 is the top width of the trapezoidal crack, and wf2 is the bottom width of the trapezoidal crack.

[0023] In some embodiments of the present application, based on the above solution, when the crack type is a trapezoidal crack, the crack volume is calculated by the following formula:

[0024] V=0.5×(wf1+wf2+h)×Lf

[0025] Wherein, V is the crack volume, Lf is the crack length, wf1 is the upper width of the trapezoidal crack, wf2 is the lower width of the trapezoidal crack, and h is the height of the trapezoidal crack.

[0026] In some embodiments of the present application, based on the above solution, when the crack type is a trapezoidal crack, the crack opening is calculated by the following formula:

[0027]

[0028] in, For rock surface relaxation, is the rock surface ratio, ρ2 is the relaxation rate, w f is the crack opening.

[0029] In some embodiments of the present application, based on the above solution, when the crack type is a wedge-shaped crack, the crack surface area is calculated by the following formula:

[0030]

[0031] Where S is the crack surface area, w f is the crack opening, Lf is the crack length, h f is the crack width, and wf2 is the bottom width of the wedge-shaped crack.

[0032] In some embodiments of the present application, based on the above solution, when the fracture type is a wedge-shaped fracture, the fracture volume is calculated by the following formula:

[0033] V=0.5×(wf2+h)×Lf

[0034] Where V is the crack volume, Lf is the crack length, wf2 is the bottom width of the wedge-shaped crack, and h is the height of the wedge-shaped crack.

[0035] In some embodiments of the present application, based on the above solution, when the crack type is a wedge-shaped crack, the crack aperture is calculated by the following formula:

[0036]

[0037] in, For rock surface relaxation, is the rock surface ratio, ρ2 is the relaxation rate, w f is the crack opening.

[0038] In some embodiments of the present application, based on the aforementioned scheme, after determining the fracture aperture of the unconventional reservoir, the method further includes: correlating the permeability per unit time, fracture width and fracture aperture according to the Hagen-Poiseuille formula; correlating the permeability per unit time, fracture permeability and fracture end face area based on Darcy's law; and determining the fracture permeability of the unconventional reservoir by combining the Hagen-Poiseuille formula and the Darcy's law.

[0039] In some embodiments of the present application, based on the above scheme, the permeability per unit time, the fracture width and the fracture aperture are related by the following formula:

[0040]

[0041] Among them, h f is the crack width, w f is the fracture aperture, Δp is the displacement pressure difference, μ is the gas viscosity, and L is the fracture length.

[0042] In some embodiments of the present application, based on the above scheme, the permeability per unit time, the fracture permeability and the fracture end surface area are related by the following formula:

[0043]

[0044] Among them, K is the fracture permeability and A is the fracture end area.

[0045] In some embodiments of the present application, based on the above scheme, when the core sample is a plug-shaped core, the fracture end surface area is calculated by the following formula:

[0046] A=h f w f

[0047] Among them, h f is the crack width, w f is the crack opening.

[0048] In some embodiments of the present application, based on the above scheme, the fracture permeability of the unconventional reservoir is calculated by the following formula:

[0049]

[0050] Where K is the fracture permeability of unconventional reservoirs, w f is the crack opening.

[0051] Compared with the prior art, the present invention has at least the following beneficial effects:

[0052] The present invention performs nuclear magnetic resonance core testing on core samples in unconventional reservoirs to obtain pore characteristics in the core samples, thereby obtaining relaxation rate and relaxation signal amplitude of the core samples by analyzing the pore characteristics of the core samples. In the process of performing nuclear magnetic resonance core testing, the core samples need to be saturated with formation fluid, so that when performing nuclear magnetic resonance core testing, the relaxation signal amplitude and relaxation rate of the hydrogen nuclei of the fluid in the pores of the core samples can be accurately measured.

[0053] Then, by analyzing the relaxation rate and relaxation signal amplitude obtained, it is possible to achieve the quantitative characterization of unconventional reservoir properties, pore size, pore type, fluid properties, and unconventional reservoir properties distribution. Therefore, by integrating the relaxation rate and relaxation signal amplitude obtained above, it is possible to obtain the nuclear magnetic resonance T2 spectrum of the core sample. In addition, the relaxation signal amplitude of the core sample is related to the porosity of the core sample, which is specifically manifested as the greater the porosity of the core sample, the greater the relaxation signal amplitude of the core sample. That is to say, the relaxation rate and nuclear magnetic resonance T2 spectrum of the core sample are affected by factors such as the size of the core sample porosity and the fluid properties in the core sample.

[0054] After obtaining the nuclear magnetic resonance T2 spectrum of the core sample, since the nuclear magnetic resonance T2 spectrum is proportional to the pore radius, in order to characterize the fracture aperture of the unconventional reservoir through the nuclear magnetic resonance T2 spectrum, the pore throat radius distribution of the core sample can be obtained by first performing a pump pressure test on the same core sample. Then, by comparing the obtained nuclear magnetic resonance T2 spectrum with the pore throat radius distribution, the conversion coefficient between the nuclear magnetic resonance T2 spectrum and the pore throat radius distribution can be found, so that the nuclear magnetic resonance T2 spectrum can be used to quantitatively obtain the pore radius distribution of the core sample, and then the pore size of the core sample can be deduced to the fracture aperture, and the fracture aperture of the unconventional reservoir can be determined based on the nuclear magnetic resonance T2 spectrum and the conversion coefficient.

[0055] It should be noted that due to the various types of fractures in unconventional reservoirs, it is necessary to construct a spatial model of the fractures in order to calculate the parameters corresponding to different types of fractures based on the spatial model, such as a trapezoidal fracture space model, a wedge-shaped fracture space model, and a parallel fracture space model.

[0056] Based on the above method, the unconventional reservoir fracture aperture calculation method provided by the present invention can improve the accuracy of unconventional reservoir fracture aperture, and can provide important technical support and theoretical basis for the subsequent evaluation of unconventional reservoirs and unconventional development.

[0057] According to a second aspect of an embodiment of the present application, a device for calculating the fracture aperture of an unconventional reservoir is provided, characterized in that the device comprises: a first acquisition unit, used to obtain the relaxation rate and relaxation signal amplitude of the core sample by performing a nuclear magnetic resonance core test on the core sample, thereby obtaining the nuclear magnetic resonance T2 spectrum of the core sample according to the relaxation rate and the relaxation signal amplitude; a second acquisition unit, used to obtain the pore throat radius distribution of the core sample by performing a pressure pump test on the core sample; a conversion unit, used to determine the conversion coefficient between the nuclear magnetic resonance T2 spectrum and the pore throat radius distribution by analyzing the nuclear magnetic resonance T2 spectrum and the pore throat radius distribution; a determination unit, used to determine the fracture aperture of the unconventional reservoir based on the nuclear magnetic resonance T2 spectrum and the conversion coefficient.

[0058] According to a third aspect of an embodiment of the present application, a computer-readable storage medium is provided, characterized in that at least one program code is stored in the computer-readable storage medium, and the at least one program code is loaded and executed by a processor to implement the operations performed by the described method.

[0059] According to a fourth aspect of an embodiment of the present application, an electronic device is provided, characterized in that the electronic device includes one or more processors and one or more memories, at least one program code is stored in the one or more memories, and the at least one program code is loaded and executed by the one or more processors to implement the operations performed by the method.

[0060] The beneficial effects of each embodiment of the second to fourth aspects mentioned above can refer to the beneficial effects of the first aspect and each embodiment of the first aspect mentioned above, and will not be repeated here.

[0061] It should be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0062] The drawings herein are incorporated into the specification and constitute a part of the specification, showing embodiments consistent with the present application, and together with the specification, are used to explain the principles of the present application. Obviously, the drawings described below are only some embodiments of the present application, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work. In the drawings:

[0063] Figure 1 A flow chart showing a method for calculating the aperture of unconventional reservoir fractures in an embodiment of the present application is shown;

[0064] Figure 2 A schematic diagram of the structure of a non-conventional reservoir fracture aperture calculation device in an embodiment of the present application is shown;

[0065] Figure 3 A schematic diagram of the structure of an electronic device in an embodiment of the present application is shown. DETAILED DESCRIPTION

[0066] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0067] In addition, described feature, structure or characteristic can be combined in one or more embodiments in any suitable manner. In the following description, many specific details are provided to provide a full understanding of the embodiments of the present application. However, those skilled in the art will appreciate that the technical scheme of the present application can be put into practice without one or more of the specific details, or other methods, components, devices, steps, etc. can be adopted. In other cases, known methods, devices, realizations or operations are not shown or described in detail to avoid blurring the various aspects of the application.

[0068] The block diagrams shown in the accompanying drawings are merely functional entities and do not necessarily correspond to physically independent entities. That is, these functional entities may be implemented in software form, or in one or more hardware modules or integrated circuits, or in different networks and / or processor devices and / or microcontroller devices.

[0069] The flowcharts shown in the accompanying drawings are only exemplary and do not necessarily include all the contents and operations / steps, nor must they be executed in the order described. For example, some operations / steps can be decomposed, and some operations / steps can be combined or partially combined, so the actual execution order may change according to actual conditions.

[0070] The following is a detailed description of this application:

[0071] Figure 1 The flowchart of the method for calculating the aperture of unconventional reservoir fractures in the embodiment of the present application is shown. The method for calculating the aperture of unconventional reservoir fractures can be executed by a device with a computing and processing function, such as an unconventional reservoir fracture aperture calculation device. Figure 1 As shown, the method for calculating the aperture of unconventional reservoir fractures includes at least steps 110 to 140, which are described in detail as follows:

[0072] Step 110, performing a nuclear magnetic resonance core test on the core sample to obtain the relaxation rate and relaxation signal amplitude of the core sample, thereby obtaining the nuclear magnetic resonance T2 spectrum of the core sample according to the relaxation rate and the relaxation signal amplitude.

[0073] Step 120, obtaining the pore throat radius distribution of the core sample by performing a pump pressure test on the core sample.

[0074] Step 130, determining a conversion coefficient between the nuclear magnetic resonance T2 spectrum and the pore throat radius distribution by analyzing the nuclear magnetic resonance T2 spectrum and the pore throat radius distribution.

[0075] Step 140: determining the fracture aperture of the unconventional reservoir based on the nuclear magnetic resonance T2 spectrum and the conversion coefficient.

[0076] In the present application, by performing nuclear magnetic resonance core testing on core samples in unconventional reservoirs, the pore characteristics in the core samples can be obtained, and then the relaxation rate and relaxation signal amplitude of the core samples can be obtained by analyzing the pore characteristics of the core samples. In the process of performing nuclear magnetic resonance core testing, the core samples need to be saturated with formation fluid, so that when performing nuclear magnetic resonance core testing, the relaxation signal amplitude and relaxation rate of the hydrogen nuclei of the fluid in the pores of the core samples can be accurately measured.

[0077] By analyzing the obtained relaxation rate and relaxation signal amplitude, it is possible to quantitatively characterize the physical properties, pore size, pore type, fluid properties, and physical property distribution of unconventional reservoirs. Therefore, by integrating the obtained relaxation rate and relaxation signal amplitude, it is possible to obtain the nuclear magnetic resonance T2 spectrum of the core sample.

[0078] In addition, the relaxation signal amplitude of the core sample is related to the porosity of the core sample. Specifically, the greater the porosity of the core sample, the greater the relaxation signal amplitude of the core sample. In other words, the relaxation rate and nuclear magnetic resonance T2 spectrum of the core sample are affected by factors such as the porosity of the core sample and the properties of the fluid in the core sample.

[0079] After obtaining the nuclear magnetic resonance T2 spectrum of the core sample, since the nuclear magnetic resonance T2 spectrum is proportional to the pore radius, in order to characterize the fracture aperture of the unconventional reservoir through the nuclear magnetic resonance T2 spectrum, the pore throat radius distribution of the core sample can be obtained by first performing a pump pressure test on the same core sample. Then, by comparing the obtained nuclear magnetic resonance T2 spectrum with the pore throat radius distribution, the conversion coefficient between the nuclear magnetic resonance T2 spectrum and the pore throat radius distribution can be found, so that the pore radius distribution of the core sample can be quantitatively obtained using the nuclear magnetic resonance T2 spectrum. Furthermore, the pore size of the core sample is deduced to the fracture aperture, and the fracture aperture of the unconventional reservoir can be determined based on the nuclear magnetic resonance T2 spectrum and the conversion coefficient.

[0080] Further, in one embodiment of the present application, determining the fracture aperture of the unconventional reservoir based on the nuclear magnetic resonance T2 spectrum and the conversion coefficient may include the following steps: determining the fracture type in the unconventional reservoir according to the nuclear magnetic resonance T2 spectrum, the fracture types including trapezoidal fractures, wedge-shaped fractures, and parallel fractures; obtaining the fracture frequency of the fractures in the unconventional reservoir according to the nuclear magnetic resonance T2 spectrum, the fracture frequency characterizing the number or width of fractures per unit length or unit area; determining the fracture aperture of the unconventional reservoir based on the nuclear magnetic resonance T2 spectrum, the conversion coefficient, the fracture type, and the fracture frequency.

[0081] Specifically, due to the complex structure of unconventional reservoirs, the types of fractures in unconventional reservoirs may include trapezoidal fractures, wedge-shaped fractures, and parallel fractures. At the same time, the fracture frequencies of various fractures are also different. Therefore, the fracture types and fracture frequencies in unconventional reservoirs can be determined by analyzing the nuclear magnetic resonance T2 spectrum, thereby determining the fracture aperture of unconventional reservoirs based on the nuclear magnetic resonance T2 spectrum, conversion coefficient, fracture type, and fracture frequency.

[0082] In the process of determining the fracture aperture of the unconventional reservoir based on the nuclear magnetic resonance T2 spectrum, the conversion factor, the fracture type, and the fracture frequency, in order to realize the characterization of the fracture aperture of the unconventional reservoir through the nuclear magnetic resonance T2 spectrum, the following steps may be specifically included: using the mercury injection nuclear magnetic conversion method, the nuclear magnetic resonance T2 spectrum is characterized by rock surface relaxation, fluid relaxation, and molecular diffusion relaxation; by analyzing the relationship between the rock surface relaxation and the rock surface ratio, the rock surface ratio is used to characterize the rock surface relaxation; combining the rock surface relaxation and the rock surface ratio, and determining the fracture aperture of the unconventional reservoir based on the nuclear magnetic resonance T2 spectrum, the conversion factor, the fracture type, and the fracture frequency.

[0083] Specifically, in the oil and gas industry, the transverse relaxation time of the fluid in the pores is mainly determined by the surface relaxation time. Therefore, an important feature of rock surface relaxation is related to the rock specific surface, where the rock specific surface refers to the ratio of the surface area of ​​pores or cracks in the rock to the volume of the pores or cracks. The larger the rock specific surface, the stronger the rock surface relaxation and the longer the transverse relaxation time. Based on the above characteristics, the nuclear magnetic resonance T2 spectrum can be characterized by using rock surface relaxation, fluid relaxation, and molecular diffusion relaxation, and the rock surface relaxation can be characterized by using the rock surface ratio, thereby realizing the calculation of the fracture aperture of unconventional reservoirs.

[0084] Further, in one embodiment of the present application, the nuclear magnetic resonance T2 spectrum is characterized by the following formula:

[0085]

[0086] in, is the nuclear magnetic resonance T2 spectrum, For rock surface relaxation, is the fluid relaxation, is molecular diffusion relaxation.

[0087] Further, in one embodiment of the present application, the rock surface relaxation is characterized by the following formula:

[0088]

[0089] in, For rock surface relaxation, is the rock surface ratio, and ρ2 is the relaxation rate.

[0090] In one embodiment of the present application, after obtaining the nuclear magnetic resonance T2 spectrum of the core sample according to the relaxation rate and the relaxation signal amplitude, the method further includes steps 141 to 142:

[0091] Step 141, determining a spin echo train calculation formula according to the relaxation rate and the relaxation signal amplitude.

[0092] Step 142, performing multi-exponential fitting on the spin echo train corresponding to the relaxation rate and the relaxation signal amplitude based on the spin echo train calculation formula to obtain a relaxation time distribution curve of the nuclear magnetic resonance T2 spectrum, thereby determining the fracture aperture of the unconventional reservoir.

[0093] In the present application, the raw data of the relaxation signal amplitude and relaxation rate are spin echo trains that decay over time, and the spin echo train can be represented as a superposition of multiple decay indices. Therefore, the spin echo train can be determined as follows:

[0094]

[0095] Among them, E cho (t) is the echo amplitude at time t, T 2i is the transverse relaxation time of the ith component, Φ i is the NMR pore size of the ith component.

[0096] By performing multi-exponential fitting on the above spin echo train, the relaxation time distribution curve of the nuclear magnetic resonance T2 spectrum can be obtained. Among them, the relaxation time distribution curve can reflect the size and distribution of pores in the core sample. At the same time, the value in the relaxation time distribution curve is proportional to the pore radius of the core sample. Therefore, by studying the relaxation time distribution curve in the nuclear magnetic resonance T2 spectrum, we can have a more realistic understanding of the fracture structure of the core sample, so that we can more accurately calculate the fracture aperture of the unconventional reservoir.

[0097] In addition, before determining the fracture aperture of the unconventional reservoir based on the nuclear magnetic resonance T2 spectrum, the conversion coefficient, the fracture type, and the fracture frequency, the following steps may be specifically included: according to the fracture type, the fracture surface area and the fracture volume are calculated to obtain the rock specific surface area, and the rock specific surface area represents the ratio of the pore surface area or the fracture surface area in the rock to the pore volume or the fracture volume.

[0098] Further, in one embodiment of the present application, when the crack type is a trapezoidal crack, the crack surface area is calculated by the following formula:

[0099]

[0100] Where S is the crack surface area, w f is the crack opening, Lf is the crack length, h f is the crack width, wf1 is the top width of the trapezoidal crack, and wf2 is the bottom width of the trapezoidal crack.

[0101] Further, in one embodiment of the present application, when the crack type is a trapezoidal crack, the crack volume is calculated by the following formula:

[0102] V=0.5×(wf1+wf2+h)×Lf

[0103] Wherein, V is the crack volume, Lf is the crack length, wf1 is the upper width of the trapezoidal crack, wf2 is the lower width of the trapezoidal crack, and h is the height of the trapezoidal crack.

[0104] Further, in one embodiment of the present application, when the crack type is a trapezoidal crack, the crack opening is calculated by the following formula:

[0105]

[0106] in, For rock surface relaxation, is the rock surface ratio, ρ2 is the relaxation rate, w f is the crack opening.

[0107] Further, in one embodiment of the present application, when the crack type is a wedge-shaped crack, the crack surface area is calculated by the following formula:

[0108]

[0109] Where S is the crack surface area, w f is the crack opening, Lf is the crack length, h f is the crack width, and wf2 is the bottom width of the wedge-shaped crack.

[0110] Furthermore, in one embodiment of the present application, when the crack type is a wedge-shaped crack, the crack volume is calculated by the following formula:

[0111] V=0.5×(wf2+h)×Lf

[0112] Where V is the crack volume, Lf is the crack length, wf2 is the bottom width of the wedge-shaped crack, and h is the height of the wedge-shaped crack.

[0113] Further, in one embodiment of the present application, when the crack type is a wedge-shaped crack, the crack opening is calculated by the following formula:

[0114]

[0115] in, For rock surface relaxation, is the rock surface ratio, ρ2 is the relaxation rate, w f is the crack opening.

[0116] In addition to the specific steps mentioned above, the unconventional reservoir fracture aperture calculation method in the present application can also be used to correlate the permeability per unit time, the fracture width and the fracture aperture according to the Hagen-Poiseuille formula. Based on Darcy's law, the permeability per unit time, the fracture permeability and the fracture end surface area are correlated. In combination with the Hagen-Poiseuille formula and the Darcy's law, the fracture permeability of the unconventional reservoir is determined.

[0117] The permeability is one of the physical property parameters of unconventional reservoirs. In this application, by calculating the fracture permeability of fractures in unconventional reservoirs, it is possible to provide a direct basis for the exploration and development of unconventional reservoirs and solve practical problems in similar oil reservoir exploration and development.

[0118] Further, in one embodiment of the present application, the permeability per unit time, the fracture width and the fracture aperture are related by the following formula:

[0119]

[0120] Among them, h f is the crack width, w f is the fracture aperture, Δp is the displacement pressure difference, μ is the gas viscosity, and L is the fracture length.

[0121] Furthermore, in one embodiment of the present application, the permeability per unit time, the fracture permeability and the fracture end surface area are related by the following formula:

[0122]

[0123] Among them, K is the fracture permeability and A is the fracture end area.

[0124] Further, in one embodiment of the present application, when the core sample is a plug-shaped core, the fracture end surface area is calculated by the following formula:

[0125] A=hfwf

[0126] Among them, h f is the crack width, w f is the crack opening.

[0127] Further, in one embodiment of the present application, the fracture permeability of the unconventional reservoir is calculated by the following formula:

[0128]

[0129] Where K is the fracture permeability of unconventional reservoirs, w f is the crack opening.

[0130] Based on the same inventive concept, the present application also provides a device for calculating the aperture of unconventional reservoir fractures, referring to Figure 2 , shows a schematic diagram of the structure of the unconventional reservoir fracture aperture calculation device in the embodiment of the present application. The unconventional reservoir fracture aperture calculation device 200 includes: a first acquisition unit 201, used to obtain the relaxation rate and relaxation signal amplitude of the core sample by performing a nuclear magnetic resonance core test on the core sample, thereby obtaining the nuclear magnetic resonance T2 spectrum of the core sample according to the relaxation rate and the relaxation signal amplitude; a second acquisition unit 202, used to obtain the pore throat radius distribution of the core sample by performing a pressure pump test on the core sample; a conversion unit 203, used to determine the conversion coefficient between the nuclear magnetic resonance T2 spectrum and the pore throat radius distribution by analyzing the nuclear magnetic resonance T2 spectrum and the pore throat radius distribution; a determination unit 204, used to determine the fracture aperture of the unconventional reservoir based on the nuclear magnetic resonance T2 spectrum and the conversion coefficient.

[0131] For details not disclosed in the embodiments of the device of the present application, please refer to the embodiments of the above method of the present application.

[0132] Based on the same inventive concept, the present application may also provide a computer-readable storage medium, characterized in that at least one program code is stored in the computer-readable storage medium, and the at least one program code is loaded and executed by a processor to implement the operations performed by the method described.

[0133] Based on the same inventive concept, the present application also provides an electronic device, referring to Figure 3 , Figure 3 A schematic diagram of the structure of an electronic device in an embodiment of the present application is shown.

[0134] The electronic device includes one or more memories 304, one or more processors 302, and at least one computer program (program code) stored in the memory 304 and executable on the processor 302. When the processor 302 executes the computer program, the method described above is implemented.

[0135] Among them, Figure 3In the embodiment of the present invention, a bus architecture (represented by bus 300) is shown, which may include any number of interconnected buses and bridges, and bus 300 links various circuits including one or more processors represented by processor 302 and memory represented by memory 304. Bus 300 may also link various other circuits such as peripherals, voltage regulators, and power management circuits, which are well known in the art and are therefore not further described herein. Bus interface 305 provides an interface between bus 300 and receiver 301 and transmitter 303. Receiver 301 and transmitter 303 may be the same element, namely a transceiver, providing a unit for communicating with various other devices over a transmission medium. Processor 302 is responsible for managing bus 300 and general processing, while memory 304 may be used to store data used by processor 302 when performing operations.

[0136] The functions described herein may be implemented in hardware, software executed by a processor, firmware, or any combination thereof. If implemented in software executed by a processor, the functions may be stored as one or more instructions or codes on a computer-readable medium or transmitted via a computer-readable medium. Other examples and implementations are within the scope and spirit of the present application and the appended claims. For example, due to the nature of software, the functions described above may be implemented using software executed by a processor, hardware, firmware, hard wiring, or a combination of any of these. In addition, each functional unit may be integrated into a processing unit, each unit may exist physically separately, or two or more units may be integrated into one unit.

[0137] In the several embodiments provided in this application, it should be understood that the disclosed technical content can be implemented in other ways. Among them, the device embodiments described above are only schematic. For example, the division of the units can be a logical function division. There may be other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of units or modules, which can be electrical or other forms.

[0138] The units described as separate components may or may not be physically separated, and the components of the control device may or may not be physical units, that is, they may be located in one place or distributed in multiple units. Some or all of the units may be selected according to actual needs to achieve the purpose of the present embodiment.

[0139] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application, in essence, or the part that contributes to the prior art or all or part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions to enable a computer device (which can be a personal computer, a server or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes: U disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), mobile hard disk, disk or optical disk and other media that can store program codes.

[0140] The above description is only an embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent substitution, improvement, etc. made within the spirit and principle of the present application shall be included in the scope of the claims of the present application.

Claims

1. A method for calculating the aperture of unconventional reservoir fractures, characterized in that: The method comprises: By performing a nuclear magnetic resonance core test on the core sample, a relaxation rate and a relaxation signal amplitude of the core sample are obtained, thereby obtaining a nuclear magnetic resonance T2 spectrum of the core sample according to the relaxation rate and the relaxation signal amplitude; Obtaining the pore throat radius distribution of the core sample by performing a pump pressure test on the core sample; Determine a conversion coefficient between the nuclear magnetic resonance T2 spectrum and the pore throat radius distribution by analyzing the nuclear magnetic resonance T2 spectrum and the pore throat radius distribution; The fracture aperture of the unconventional reservoir is determined based on the nuclear magnetic resonance T2 spectrum and the conversion coefficient.

2. The method according to claim 1, characterized in that After obtaining the nuclear magnetic resonance T2 spectrum of the core sample according to the relaxation rate and the relaxation signal amplitude, the method further comprises: Determining a spin echo train calculation formula according to the relaxation rate and the relaxation signal amplitude; Based on the spin echo train calculation formula, multi-exponential fitting is performed on the spin echo train corresponding to the relaxation rate and the relaxation signal amplitude to obtain the relaxation time distribution curve of the nuclear magnetic resonance T2 spectrum, thereby determining the fracture aperture of the unconventional reservoir.

3. The method according to claim 2, characterized in that The spin echo train is determined as follows: Among them, E cho (t) is the echo amplitude at time t, T 2i is the transverse relaxation time of the ith component, Φ i is the NMR pore size of the ith component.

4. The method according to claim 1, characterized in that: The determining of the fracture aperture of the unconventional reservoir based on the nuclear magnetic resonance T2 spectrum and the conversion coefficient comprises: Determining the fracture types in the unconventional reservoir according to the nuclear magnetic resonance T2 spectrum, wherein the fracture types include trapezoidal fractures, wedge-shaped fractures, and parallel fractures; Obtaining the fracture frequency of fractures in the unconventional reservoir according to the nuclear magnetic resonance T2 spectrum, wherein the fracture frequency represents the number or width of fractures per unit length or unit area; The fracture aperture of the unconventional reservoir is determined based on the nuclear magnetic resonance T2 spectrum, the conversion factor, the fracture type, and the fracture frequency.

5. The method according to claim 4, characterized in that In the process of determining the fracture aperture of the unconventional reservoir based on the nuclear magnetic resonance T2 spectrum, the conversion factor, the fracture type, and the fracture frequency, the method further includes: The NMR T2 spectrum is characterized by utilizing rock surface relaxation, fluid relaxation, and molecular diffusion relaxation through mercury injection nuclear magnetic conversion system method; By analyzing the relationship between the rock surface relaxation and the rock surface ratio, the rock surface relaxation is characterized by using the rock surface ratio; The fracture aperture of the unconventional reservoir is determined by combining the rock surface relaxation and the rock surface ratio and based on the nuclear magnetic resonance T2 spectrum, the conversion factor, the fracture type, and the fracture frequency.

6. The method according to claim 5, characterized in that The NMR T2 spectrum is characterized by the following formula: in, is the nuclear magnetic resonance T2 spectrum, For rock surface relaxation, is the fluid relaxation, is molecular diffusion relaxation.

7. The method according to claim 5, characterized in that The rock surface relaxation is characterized by the following formula: in, For rock surface relaxation, is the rock surface ratio, and ρ2 is the relaxation rate.

8. The method according to claim 4, characterized in that Before determining the fracture aperture of the unconventional reservoir based on the nuclear magnetic resonance T2 spectrum, the conversion factor, the fracture type, and the fracture frequency, the method further includes: According to the fracture type, the fracture surface area and fracture volume are calculated to obtain the rock specific surface, which represents the ratio of the pore surface area or fracture surface area to the pore volume or fracture volume in the rock.

9. The method according to claim 8, characterized in that When the crack type is a trapezoidal crack, the crack surface area is calculated by the following formula: Where S is the crack surface area, w f is the crack opening, Lf is the crack length, h f is the crack width, wf1 is the top width of the trapezoidal crack, and wf2 is the bottom width of the trapezoidal crack.

10. The method according to claim 8, characterized in thatWhen the crack type is a trapezoidal crack, the crack volume is calculated by the following formula: V=0.5×(wf1+wf2+h)×Lf Wherein, V is the crack volume, Lf is the crack length, wf1 is the upper width of the trapezoidal crack, wf2 is the lower width of the trapezoidal crack, and h is the height of the trapezoidal crack.

11. The method according to claim 8, characterized in that When the crack type is a trapezoidal crack, the crack opening is calculated by the following formula: in, For rock surface relaxation, is the rock surface ratio, ρ2 is the relaxation rate, w f is the crack opening.

12. The method according to claim 8, characterized in that When the crack type is a wedge-shaped crack, the crack surface area is calculated by the following formula: Where S is the crack surface area, w f is the crack opening, Lf is the crack length, h f is the crack width, and wf2 is the bottom width of the wedge-shaped crack.

13. The method according to claim 8, characterized in that When the crack type is a wedge-shaped crack, the crack volume is calculated by the following formula: V=0.5×(wf2+h)×Lf Where V is the crack volume, Lf is the crack length, wf2 is the bottom width of the wedge-shaped crack, and h is the height of the wedge-shaped crack.

14. The method according to claim 8, characterized in that When the crack type is a wedge-shaped crack, the crack opening is calculated by the following formula: in, For rock surface relaxation, is the rock surface ratio, ρ2 is the relaxation rate, w f is the crack opening.

15. The method according to claim 1, characterized in that After determining the fracture aperture of the unconventional reservoir, the method further comprises: According to the Hagen-Poiseuille formula, the permeability per unit time, the crack width and the crack aperture are related; Based on Darcy's law, the permeability per unit time, fracture permeability and fracture end area are related; The fracture permeability of the unconventional reservoir is determined by combining the Hagen-Poiseuille formula and the Darcy law.

16. The method according to claim 15, characterized in that The permeability per unit time, fracture width, and fracture aperture are related by the following formula: Among them, h f is the crack width, w f is the fracture aperture, Δp is the displacement pressure difference, μ is the gas viscosity, and L is the fracture length.

17. The method according to claim 15, characterized in that The permeability per unit time, fracture permeability, and fracture end area are related by the following formula: Among them, K is the fracture permeability and A is the fracture end area.

18. The method according to claim 15, characterized in that When the core sample is a plug-shaped core, the fracture end surface area is calculated by the following formula: A=h f w f Among them, h f is the crack width, w f is the crack opening.

19. The method according to claim 15, characterized in that The fracture permeability of the unconventional reservoir is calculated by the following formula: Where K is the fracture permeability of unconventional reservoirs, w f is the crack opening.

20. An unconventional reservoir fracture aperture calculation device, characterized in that: The device comprises: A first acquisition unit is used to acquire the relaxation rate and relaxation signal amplitude of the core sample by performing a nuclear magnetic resonance core test on the core sample, thereby acquiring the nuclear magnetic resonance T2 spectrum of the core sample according to the relaxation rate and the relaxation signal amplitude; A second acquisition unit is used to obtain the pore throat radius distribution of the core sample by performing a pump pressure test on the core sample; A conversion unit, used for determining a conversion coefficient between the nuclear magnetic resonance T2 spectrum and the pore throat radius distribution by analyzing the nuclear magnetic resonance T2 spectrum and the pore throat radius distribution; A determination unit is used to determine the fracture aperture of the unconventional reservoir based on the nuclear magnetic resonance T2 spectrum and the conversion coefficient.

21. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores at least one program code, and the at least one program code is loaded and executed by a processor to implement the operations performed by the method according to any one of claims 1 to 19.

22. An electronic device, characterized in that: The electronic device includes one or more processors and one or more memories, wherein the one or more memories store at least one program code, and the at least one program code is loaded and executed by the one or more processors to implement the operations performed by the method according to any one of claims 1 to 19.

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