Method and device for calculating radial velocity of fractured reservoir

Abstract

The present invention discloses a method and device for calculating radial velocity of a fractured reservoir, the method comprising: obtaining an original image of a radial section after fracture; processing the original image of the radial section to obtain a fracture picking result; calculating the fractal dimension of the coverage range of different radii according to the fracture picking result, and obtaining the fracture density of different radii according to the fractal dimension; the fracture density is proportional to the fractal dimension; calculating the corresponding radial velocity according to the fracture density of different radii and the drilling data of the fractured formation; the radial velocity includes the shear wave radial velocity and the longitudinal wave radial velocity. By processing the original image of the radial section, the fractal characteristics of the fracture are determined, so as to establish the relationship between the fracture density and the radial fractal dimension, quantitatively characterize the fracture density of the fractured formation that changes with the radial distance, and then obtain the longitudinal and shear wave radial velocities of the fractured reservoir that change with the radial depth, which is closer to the actual unconventional fractured reservoir and has high accuracy.

Description

Technical Field

[0001] The embodiments of the present invention relate to the technical fields of geophysics and petroleum exploration and development, and in particular to a method and device for calculating radial velocity of a fractured reservoir. Background Art

[0002] With the continuous improvement of offshore reservoir exploration and development, the focus of exploration has gradually shifted to unconventional reservoirs such as low porosity and permeability and shale oil. Unconventional reservoirs have the characteristics of low porosity, low permeability, and strong heterogeneity. When exploring and developing unconventional reservoirs, large-scale volume fracturing is usually adopted. In order to determine whether volume fracturing can effectively open the reservoir and open the seepage channel for oil and gas production, it is also necessary to evaluate and determine the artificial fractures generated by reservoir transformation. After the artificial fractures are generated, how the radial velocity of the fractured reservoir changes is a difficult problem in the evaluation of reservoir fracturing effect.

[0003] In the prior art, the radial velocity evaluation of the fractured reservoir is mainly based on the homogeneous formation or layered formation model, and the random medium model is used to describe the non-uniform fluctuations in the rock. However, in actual applications, after the unconventional reservoir is fractured, a large number of small cracks and fissures will first be generated, then aggregated, and finally merged, and macroscopic fractures will occur in the rock to form major cracks. The artificially initiated fractures have very significant fractal characteristics. The existing radial velocity evaluation method for the fractured reservoir does not take into account the actual fracture network morphology characteristics, and is not suitable for unconventional reservoirs with complex fracture network morphology. Summary of the invention

[0004] In view of the above problems, embodiments of the present invention are proposed to provide a method and device for calculating radial velocity of a fractured reservoir that overcomes the above problems or at least partially solves the above problems.

[0005] According to one aspect of an embodiment of the present invention, a method for calculating radial velocity of a fractured reservoir is provided, the method comprising:

[0006] Obtain the original image of the radial section after fracturing;

[0007] Process the original image of the radial section to obtain the crack picking result;

[0008] According to the crack picking results, the fractal dimension of the coverage area with different radii is calculated, and the crack density with different radii is calculated based on the fractal dimension; the crack density is proportional to the fractal dimension;

[0009] The corresponding radial velocity is calculated according to the fracture density of different radii and the drilling data of the fractured formation; the radial velocity includes the shear wave radial velocity and the longitudinal wave radial velocity.

[0010] According to another aspect of an embodiment of the present invention, there is provided a device for calculating radial velocity of a fractured reservoir, comprising:

[0011] An image module, suitable for obtaining the original image of the radial section after fracturing;

[0012] A crack picking module is suitable for processing the original image of the radial section to obtain the crack picking result;

[0013] The crack density module is suitable for calculating the fractal dimension of the coverage area of ​​different radii according to the crack picking results, and calculating the crack density of different radii according to the fractal dimension; the crack density is proportional to the fractal dimension;

[0014] The radial velocity module is suitable for calculating the corresponding radial velocity according to the fracture density of different radii and the drilling data of the fracturing formation; the radial velocity includes the shear wave radial velocity and the longitudinal wave radial velocity.

[0015] According to another aspect of an embodiment of the present invention, there is provided a computing device, comprising: a processor, a memory, a communication interface and a communication bus, wherein the processor, the memory and the communication interface communicate with each other via the communication bus;

[0016] The memory is used to store at least one executable instruction, and the executable instruction enables the processor to execute operations corresponding to the above-mentioned method for calculating the radial velocity of the fractured reservoir.

[0017] According to another aspect of the embodiments of the present invention, a computer storage medium is provided, wherein the storage medium stores at least one executable instruction, wherein the executable instruction enables a processor to execute operations corresponding to the above-mentioned method for calculating radial velocity of a fractured reservoir.

[0018] According to another aspect of an embodiment of the present invention, a computer program product is provided, comprising at least one executable instruction, wherein the executable instruction enables a processor to execute operations corresponding to the above-mentioned method for calculating radial velocity of a fractured reservoir.

[0019] According to the method and device for calculating the radial velocity of a fractured reservoir provided by an embodiment of the present invention, the fractal characteristics of the fractures are determined by processing the original image of the radial section, thereby establishing a relationship between the fracture density and the radial fractal dimension, quantitatively characterizing the fracture density of the fractured formation that varies with radial distance, and then obtaining the longitudinal and transverse wave radial velocities of the fractured reservoir that vary with radial depth, which is closer to the actual unconventional fractured reservoir and has high accuracy.

[0020] The above description is only an overview of the technical solution of the embodiment of the present invention. In order to more clearly understand the technical means of the embodiment of the present invention, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the embodiment of the present invention more obvious and easy to understand, the specific implementation method of the embodiment of the present invention is specifically listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the embodiments of the present invention. Moreover, the same reference symbols are used throughout the accompanying drawings to represent the same components. In the accompanying drawings:

[0022] Figure 1 A flow chart showing a method for calculating radial velocity of a fractured reservoir according to an embodiment of the present invention;

[0023] Figure 2 The original image of the radial section of the main fracture type of the wellbore of the fracturing specimen after fracturing is shown;

[0024] Figure 3 The original image of the radial section of the wellbore mesh type of the fracturing specimen after fracturing is shown;

[0025] Figure 4 A schematic diagram of crack boundary optimization based on dilation corrosion processing is shown;

[0026] Figure 5 A schematic diagram of fractal calculation of coverage range with different radii is shown;

[0027] Figure 6 A schematic diagram of the radial fractal dimension curve of the wellbore network-type hydraulic fracture is shown;

[0028] Figure 7 The schematic diagram of the radial fractal dimension curve of the main fracture type of the wellbore is shown;

[0029] Figure 8 A schematic diagram of radial fracture density curve of wellbore network-type hydraulic fractures is shown;

[0030] Fig. 9 A schematic diagram of the radial fracture density curve of the main fracture type hydraulic fracture in the wellbore is shown;

[0031] Fig.10 A schematic diagram of radial longitudinal and transverse wave velocity curves of a wellbore network-type fracture reservoir is shown;

[0032] Fig.11 A schematic diagram of radial longitudinal and transverse wave velocity curves of a wellbore main seam type fracture reservoir is shown;

[0033] Fig.12 A schematic diagram showing the structure of a device for calculating radial velocity of a fractured reservoir according to an embodiment of the present invention is shown;

[0034] Fig.13 A schematic diagram of the structure of a computing device according to an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0035] The exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided in order to enable a more thorough understanding of the present invention and to enable the scope of the present invention to be fully communicated to those skilled in the art.

[0036] Figure 1 FIG. 4 is a flow chart showing a method for calculating radial velocity of a fractured reservoir according to an embodiment of the present invention. Figure 1 As shown, the method comprises the following steps:

[0037] Step S101, obtaining the original image of the radial section after fracturing.

[0038] The original image of the radial section can be obtained through fracturing processing. For example, the fracturing specimen is placed in a triaxial pressure device. To ensure balanced pressure distribution, the triaxial pressure device can be equipped with a spherical plate and a hydraulic pump with a maximum injection pressure of, for example, 140 MPa. A hole is drilled in the fracturing specimen and fracturing fluid is injected along the wellbore at a constant flow rate. While keeping the vertical stress unchanged, the maximum horizontal principal stress σH and the minimum horizontal principal stress σh are changed to obtain the original image of the radial section of the fracturing specimen after fracturing with different crack morphologies. The original image of the radial section includes main seam type and mesh type fractures. The original image of the radial section is as follows: Figure 2 and Figure 3 As shown, Figure 2 The original image of the radial section of the fracturing specimen obtained for the main fracture of the wellbore. Figure 2 In the middle, 1 is the wellbore and 2 is the fracture. Figure 3 The original image of the radial section of the fracturing specimen obtained for the wellbore network fracture. Figure 3 In the middle, 1 is the wellbore and 2 is the fracture.

[0039] Step S102, processing the original radial section image to obtain a crack picking result.

[0040] According to the obtained radial section original image, the radial section original image can be digitally processed, such as performing perspective stretching and grayscale processing on the radial section original image to obtain an image digital matrix of the radial section original image, such as a matrix Im xn of size mxn, that is, using digital representation to obtain a digitized image.

[0041] By enhancing the image digital matrix, the enhanced image matrix can be obtained based on the image digital matrix and the Hessian matrix of the original profile image. The Hessian matrix characterizes the rate of change of the grayscale at the junction, which is the second-order partial derivative of the grayscale pixel point, and its form is as follows:

[0042]

[0043] The residual fracturing fluid filling the cracks will produce a stronger color difference compared with the wet area or non-fracturing area, causing a sharp change in the grayscale (color difference) at the junction. The Hessian matrix records the rate of change of grayscale. x, y are the coordinates in the image, x is 1-m, and y is 1-n.

[0044] For the Hessian matrix, since the image digital matrix Im xn is discrete, by introducing the scale factor , constructed with Gaussian function with standard deviation , and then based on the Gaussian function Convolve with the image digital matrix Im xn to obtain the scale space derivative I ab , the scale space derivative I ab Substitute into the above Hessian matrix, with I ab Substitute I in the Hessian matrix IC2 formula to obtain the Hessian matrix of the original profile image.

[0045] Constructing the Gaussian function is as follows:

[0046]

[0047] Among them, x and y are the coordinates in the image.

[0048] The Gaussian function Convolve with the image digital matrix Im xn to obtain the scale space derivative I ab , as shown below:

[0049]

[0050] Among them, x and y are coordinates in the image, representing two different directions in the image coordinate system, or any two orthogonal directions in the image.

[0051] The obtained Hessian matrix IC2 of the original image of the profile is a 2×2 matrix, and the two-dimensional linear filter is determined according to the eigenvalues ​​of the Hessian matrix. Among them, the Hessian matrix has a symmetric property, which includes eigenvalues ​​λ1 and λ2, which respectively mark the minimum and maximum change directions of the local image digital matrix Im xn, corresponding to the crack trajectory and the direction perpendicular to the crack trajectory. The calculation method of λ1 and λ2 is as follows:

[0052]

[0053]

[0054]

[0055]

[0056] Determine the two-dimensional linear filter according to the eigenvalues ​​λ1 and λ2. For example, when |λ1|≥|λ2|, the two-dimensional linear filter Z line As shown below:

[0057]

[0058] By adjusting the scale factor , so that it matches the crack trajectory broadband of the original profile image, determine the maximum value of the two-dimensional linear filter, multiply the maximum value of the two-dimensional linear filter by the scale factor, and obtain the enhanced image matrix Lm xn.

[0059] Based on the enhanced image matrix Lm xn, a preset operator, such as the Sobel operator, is used to perform convolution processing on the enhanced image matrix to extract the boundary and obtain the crack boundary. The Sobel operator includes operators in the x-direction and the y-direction. For example, taking the kernel size of 3 as an example, the x-direction operator is:

[0060]

[0061] The y-direction operator is:

[0062]

[0063] The x-direction operator S x and the y-direction operator S y Convolve with the enhanced image matrix Lm xn respectively to calculate the gradient values ​​of the original image of the radial section in the x and y directions. Repeat the calculation for each pixel point of the enhanced image matrix Lm xn and perform binarization to obtain the crack boundary.

[0064] Based on the further judgment of the crack boundary, the cracks with a width greater than the preset width threshold are subjected to expansion corrosion processing. For example, if the preset width threshold is 3 pixels, the cracks with a width greater than 3 pixels are thickened by the expansion algorithm, so that the two crack surface trajectories of the cracks touch and overlap, and then the overall width is reduced by the corrosion algorithm to obtain the ideal actual crack expansion trajectory. Figure 4 As shown, Figure 4The leftmost figure in the figure is to abstract the redundancy of the crack trajectory into two concentric circles, representing its redundancy in different expansion directions, where white means containing cracks, which can be recorded as 1, and black means no cracks, which can be recorded as 0. The values ​​of the 3×3 pixel matrix points in the leftmost figure are counted with each pixel as the center. When at least one pixel is not 0 (no crack), the central pixel of the pixel matrix is ​​set to 1 (containing cracks) and the expansion process is performed to obtain the following Figure 4 The white ring in the middle image. Then perform corrosion processing, such as counting the values ​​of the 3×3 pixel matrix points in the leftmost image with each pixel as the center. When at least one pixel is not 1 (including cracks), set the center pixel of the pixel matrix to 0 (no cracks) and perform corrosion processing to obtain the following Figure 4 The white circle shown on the right. The final crack picking result is obtained by dilation corrosion processing of the crack redundancy. Here, the main seam type pressure fracture and the network type pressure fracture can be processed separately to obtain the main seam type pressure fracture picking result and the network type pressure fracture picking result respectively.

[0065] Step S103, calculating the fractal dimensions of coverage areas of different radii according to the crack picking results, and obtaining the crack densities of different radii according to the fractal dimensions.

[0066] Based on the crack picking results obtained, the fractal dimension of the coverage area with different radii can be calculated. The radius setting can be as follows Figure 5 As shown in the figure, first determine the borehole radius of the original radial profile image, such as Figure 5 The central gray circle is the wellbore. The wellbore radius is set to the initial radius r, and then the new radius is obtained by increasing the initial radius by a preset exponential, such as Figure 5 The gray lines with arrows are different radii, and the fractal dimensions of the coverage areas with different radii can be calculated.

[0067] The calculation of fractal dimension is as follows: taking the borehole as the center, determine the initial radius r, determine the number of pixels or bits N(r) covering the cracks within the coverage range of the initial radius r, and obtain the fractal dimension D of the coverage range of the initial radius according to the number of pixels or bits N(r). f .

[0068]

[0069] In order to obtain the fractal dimension of different radii, the initial radius can be increased by a preset exponent (such as exponent 2) to obtain a new radius, and then the fractal dimension of the coverage range of the new radius is calculated based on the new radius, and the radius is repeatedly updated until the coverage range of the radius covers the original image of the radial section, that is, it is equivalent to or equal to the observation domain of the crack in the original image of the radial section, and the fractal dimension of the coverage range of each radius is obtained. Figure 6As shown, the horizontal axis is the radius in meters, and the vertical axis is the fractal dimension. According to the calculated fractal dimension D f It is dimensionless, and the curve represents the different radial fractal dimensions of the wellbore network-type fractures; Figure 7 As shown, the horizontal axis is the radius in meters, and the vertical axis is the fractal dimension. According to the calculated fractal dimension D f It is dimensionless, and the curves represent the different radial fractal dimensions of the main fracture type of the wellbore.

[0070] According to the fractal dimension of the coverage range of each radius, based on the proportional relationship between the crack density in the rock and the fractal dimension, combined with the conversion relationship between pixel points and distance, the crack density ε of each radius is calculated. mic (r):

[0071]

[0072] Among them, RF is a preset proportional factor, which is related to factors such as rock physical parameters and geological stress state, and can be set according to specific implementation conditions, thereby obtaining a proportional relationship between fracture density and fractal dimension. Figure 8 As shown, the horizontal axis is the radius in meters, the vertical axis is the crack density, and the fractal dimension D f Dimensionless, according to the fractal dimension D f The crack density ε mic (r) dimensionless, the curve is the fracture density of the wellbore network fractures in different radial directions; Fig. 9 As shown, the horizontal axis is the radius in meters, the vertical axis is the crack density, and the fractal dimension D f Dimensionless, according to the fractal dimension D f The crack density ε mic (r) Dimensionless, the curve represents the fracture density of the main fracture type fracture in the wellbore at different radial directions.

[0073] Step S104, calculating corresponding radial velocities according to fracture densities of different radii and drilling data of the fractured formation.

[0074] The radial velocity includes the shear wave radial velocity v sr and the longitudinal wave radial velocity v pr Among them, the radial velocity of shear waves and the radial velocity of longitudinal waves are both related to the crack density in different radial directions. Based on the unified theory of elastic waves in porous and fractured media and the crack density in different radial directions, the radial velocity of shear waves and the radial velocity of longitudinal waves in different radial directions can be calculated.

[0075] The longitudinal wave radial velocity can be calculated based on the density of saturated rock, equivalent seepage density, density of pore fluid, storage modulus of porous fracture medium, low-frequency P wave modulus of saturated rock, modulus, etc., among which the storage modulus of porous fracture medium is obtained according to the fracture density of different radii. The shear wave radial velocity is calculated based on the density of saturated rock, equivalent seepage density, density of pore fluid and shear modulus of saturated rock, the shear modulus of saturated rock is obtained according to the storage modulus of porous fracture medium, and the storage modulus of porous fracture medium is obtained according to the fracture density of different radii, so both the shear wave radial velocity and the longitudinal wave radial velocity are related to the fracture density of different radials.

[0076] The details are as follows:

[0077]

[0078]

[0079]

[0080]

[0081] Wherein, Re represents the real part operator of complex numbers. is the density of pore fluid, ρ is the density of saturated rock, ρ' is the equivalent seepage density, . is an imaginary unit, η is the fluid viscosity, ω is the angular frequency, κ(ω) is the dynamic permeability, κ0 is the static Darcy permeability, is the critical frequency of Biot macroscopic flow. H is the low-frequency P-wave modulus of saturated rock, , K m is the volume of saturated rock, and μ is the shear modulus of saturated rock. , . K d is the bulk modulus of the dry skeleton of the porous medium, α is the Biot-Wills coefficient, M is the storage modulus of the porous medium, and M1 is the storage modulus of the porous medium. The bulk modulus of porous fracture media when squeezing flow is not considered is: is the shear modulus of porous fracture medium when squeezing flow is not considered. C is the modulus, C=αM. , .in, is the porosity, is the bulk modulus of the solid skeleton particles, is the bulk modulus of the fluid, S(r, ω) is the fracture squeezing flow function, and is related to the radial fracture density ε mic (r) related, ε mic (r) is the radial crack density at different radial r, is the Poise ratio when the squeezing jet is not considered, is the crack aspect ratio, N is the crack to pore size ratio parameter, and λ is the intermediate parameter used in N calculation.

[0082] The shear wave radial velocity and longitudinal wave radial velocity can be calculated by the calculation formula of the shear wave radial velocity and the longitudinal wave radial velocity. For the main seam type fracture and the network type fracture, the corresponding shear wave radial velocity and longitudinal wave radial velocity can be calculated respectively. Take the fracturing of the fracturing specimen at a frequency of 10 kHz as an example. Fig.10 As shown, the horizontal axis is the radius in meters, and the vertical axis is the speed in kilometers per second. Fig.10 The middle curve is the radial P- and S-wave velocity of the wellbore network-type fracture reservoir, v s is the radial velocity curve of shear wave, v p is the longitudinal wave radial velocity curve; Fig.11 As shown, the horizontal axis is the radius in meters, and the vertical axis is the speed in kilometers per second. Fig.11 The middle curve is the radial P- and S-wave velocity of the main fracture type reservoir in the wellbore, v s is the radial velocity curve of shear wave, v p is the longitudinal wave radial velocity curve.

[0083] Based on the radial position of different radii r, the radial velocity v of the longitudinal and transverse waves of the fractured formation at the corresponding radial distance can be obtained. pr (r), v sr (r), the radial velocity of the fractured reservoir that varies with radial depth is obtained, which is closer to the actual unconventional fractured reservoir and has high accuracy. It also facilitates the evaluation of unconventional low-permeability fractured reservoirs.

[0084] According to the method for calculating the radial velocity of a fractured reservoir provided by an embodiment of the present invention, the fractal characteristics of the fractures are determined by processing the original image of the radial section, thereby establishing a relationship between the fracture density and the radial fractal dimension, quantitatively characterizing the fracture density of the fractured formation that varies with radial distance, and then obtaining the longitudinal and transverse wave radial velocities of the fractured reservoir that vary with radial depth, which is closer to the actual unconventional fractured reservoir and has high accuracy.

[0085] Fig.12 FIG. 2 is a schematic diagram showing the structure of a device for calculating radial velocity of a fractured reservoir provided by an embodiment of the present invention. Fig.12 As shown, the device comprises:

[0086] An image module 1210 is adapted to obtain an original image of a radial section after fracturing;

[0087] The crack picking module 1220 is adapted to process the original radial section image to obtain a crack picking result;

[0088] The crack density module 1230 is adapted to calculate the fractal dimension of the coverage range of different radii according to the crack picking result, and calculate the crack density of different radii according to the fractal dimension; the crack density is proportional to the fractal dimension;

[0089] The radial velocity module 1240 is adapted to calculate the corresponding radial velocity according to the fracture density of different radii and the drilling data of the fractured formation; the radial velocity includes the shear wave radial velocity and the longitudinal wave radial velocity.

[0090] Optionally, the crack picking module 1220 is further adapted to:

[0091] Perform perspective stretching and grayscale processing on the original image of the radial section to obtain an image digital matrix of the original image of the radial section;

[0092] The enhanced image matrix is ​​obtained according to the image digital matrix and the Hessian matrix of the original image of the cross section;

[0093] The enhanced image matrix is ​​convolved according to a preset operator to obtain the crack boundary;

[0094] Based on the crack boundary, cracks with a width greater than a preset width threshold are subjected to expansion corrosion processing to obtain crack picking results.

[0095] Optionally, the crack picking module 1220 is further adapted to:

[0096] A Gaussian function is constructed according to the scale factor, and convolved with the image digital matrix to obtain the scale space derivative;

[0097] Determine the Hessian matrix of the original image of the profile according to the scale space derivative, and determine the two-dimensional linear filter according to the eigenvalue of the Hessian matrix;

[0098] The enhanced image matrix is ​​obtained by multiplying the maximum value of the two-dimensional linear filter by the scale factor, wherein the scale factor matches the crack track broadband of the original profile image.

[0099] Optionally, the fracture density module 1230 is further adapted to:

[0100] Determine the borehole radius of the original image of the radial section, and set the borehole radius as the initial radius;

[0101] Taking the wellbore as the center, determine the number of pixels or bits covering the fracture within the coverage range of the initial radius, and obtain the fractal dimension of the coverage range of the initial radius according to the number of pixels or bits; increase the initial radius by a preset exponential to obtain a new radius, calculate the fractal dimension of the coverage range of the new radius, and repeatedly update the radius until the coverage range of the radius covers the original image of the radial section;

[0102] The crack density of each radius is calculated based on the fractal dimension of the coverage range of each radius and the preset scale factor.

[0103] Optionally, radial velocity module 1240 is further adapted to:

[0104] The radial velocity of longitudinal waves is calculated based on the density of saturated rock, equivalent seepage density, density of pore fluid, storage modulus of porous fracture medium, low-frequency P-wave modulus and modulus of saturated rock; among which, the storage modulus of porous fracture medium is obtained based on the fracture density of different radii;

[0105] The radial velocity of shear waves is calculated based on the density of saturated rock, equivalent seepage density, density of pore fluid and shear modulus of saturated rock; the shear modulus of saturated rock is obtained based on the storage modulus of porous and fractured media.

[0106] Optionally, the radial section original image includes main seam type fractures and network type fractures.

[0107] The description of each module above refers to the corresponding description in the method embodiment and will not be repeated here.

[0108] An embodiment of the present invention further provides a non-volatile computer storage medium, which stores at least one executable instruction, and the executable instruction can execute operations corresponding to the method for calculating the radial velocity of a fractured reservoir in any of the above method embodiments.

[0109] An embodiment of the present application provides a computer program product, which includes at least one executable instruction or computer program, and the executable instruction or computer program can enable a processor to perform operations corresponding to the method for calculating the radial velocity of a fractured reservoir in any of the above method embodiments.

[0110] Fig.13 A schematic diagram of the structure of a computing device according to an embodiment of the present invention is shown, and the specific implementation of the embodiment of the present invention does not limit the specific implementation of the computing device.

[0111] like Fig.13 As shown, the computing device may include: a processor 1302 , a communication interface 1304 , a memory 1306 , and a communication bus 1308 .

[0112] in:

[0113] The processor 1302 , the communication interface 1304 , and the memory 1306 communicate with each other via a communication bus 1308 .

[0114] The communication interface 1304 is used to communicate with other devices such as clients or other servers.

[0115] The processor 1302 is used to execute the program 1310, and specifically can execute the relevant steps in the above-mentioned embodiment of the method for calculating the radial velocity of the fractured reservoir.

[0116] Specifically, the program 1310 may include program codes, which include computer operation instructions.

[0117] The processor 1302 may be a central processing unit (CPU), or a specific integrated circuit (ASIC), or one or more integrated circuits configured to implement the embodiments of the present invention. The one or more processors included in the computing device may be processors of the same type, such as one or more CPUs; or processors of different types, such as one or more CPUs and one or more ASICs.

[0118] The memory 1306 is used to store the program 1310. The memory 1306 may include a high-speed RAM memory, and may also include a non-volatile memory, such as at least one disk memory.

[0119] The program 1310 can be specifically used to enable the processor 1302 to execute the calculation method of the radial velocity of the fractured reservoir in any of the above-mentioned method embodiments. The specific implementation of each step in the program 1310 can refer to the corresponding descriptions in the corresponding steps and units in the above-mentioned calculation embodiment of the radial velocity of the fractured reservoir, which will not be repeated here. Those skilled in the art can clearly understand that for the convenience and simplicity of description, the specific working process of the above-mentioned device and module can refer to the corresponding process description in the above-mentioned method embodiment, which will not be repeated here.

[0120] The algorithm or display provided herein is not inherently related to any particular computer, virtual system or other device. Various general purpose systems can also be used together with the teachings based on this. According to the above description, it is obvious that the structure required for constructing such systems. In addition, the embodiment of the present invention is not directed to any specific programming language either. It should be understood that various programming languages ​​can be utilized to realize the content of the embodiment of the present invention described herein, and the description of the above specific language is to disclose the preferred implementation of the embodiment of the present invention.

[0121] In the description provided herein, a large number of specific details are described. However, it is understood that embodiments of the present invention can be practiced without these specific details. In some instances, well-known methods, structures and techniques are not shown in detail so as not to obscure the understanding of this description.

[0122] Similarly, it should be understood that in order to streamline the embodiments of the present invention and to aid in understanding one or more of the various inventive aspects, in the above description of the exemplary embodiments of the present invention, the various features of the embodiments of the present invention are sometimes grouped together into a single embodiment, figure, or description thereof. However, the disclosed method should not be interpreted as reflecting the following intention: that the claimed embodiments of the present invention require more features than the features explicitly recited in each claim. More specifically, as reflected in the claims below, the inventive aspects lie in less than all the features of the single embodiment disclosed above. Therefore, the claims that follow the specific embodiment are hereby expressly incorporated into the specific embodiment, wherein each claim itself serves as a separate embodiment of the present invention.

[0123] Those skilled in the art will appreciate that the modules in the devices in the embodiments may be adaptively changed and arranged in one or more devices different from the embodiments. The modules or units or components in the embodiments may be combined into one module or unit or component, and further may be divided into a plurality of submodules or subunits or subcomponents. All features disclosed in this specification (including the accompanying claims, abstracts and drawings) and all processes or units of any method or device so disclosed may be combined in any combination, except that at least some of such features and / or processes or units are mutually exclusive. Unless otherwise expressly stated, each feature disclosed in this specification (including the accompanying claims, abstracts and drawings) may be replaced by an alternative feature that provides the same, equivalent or similar purpose.

[0124] In addition, those skilled in the art will appreciate that, although some embodiments herein include certain features included in other embodiments but not other features, the combination of features of different embodiments is meant to be within the scope of the present invention and form different embodiments. For example, in the claims below, any one of the claimed embodiments may be used in any combination.

[0125] The various component embodiments of the present invention may be implemented in hardware, or in software modules running on one or more processors, or in a combination thereof. It should be understood by those skilled in the art that a microprocessor or a digital signal processor (DSP) may be used in practice to implement some or all of the functions of some or all of the components according to the embodiments of the present invention. The embodiments of the present invention may also be implemented as a device or apparatus program (e.g., a computer program and a computer program product) for executing part or all of the methods described herein. Such a program for implementing an embodiment of the present invention may be stored on a computer-readable medium, or may be in the form of one or more signals. Such a signal may be downloaded from an Internet website, or provided on a carrier signal, or provided in any other form.

[0126] It should be noted that the above embodiments illustrate rather than limit the present invention, and that those skilled in the art may devise alternative embodiments without departing from the scope of the appended claims. In the claims, any reference symbol between brackets shall not be construed as a limitation on the claims. The word "comprising" does not exclude the presence of elements or steps not listed in the claims. The word "one" or "an" preceding an element does not exclude the presence of a plurality of such elements. The present invention may be implemented by means of hardware comprising a number of different elements and by means of a suitably programmed computer. In a unit claim listing a number of devices, several of these devices may be embodied by the same hardware item. The use of the words first, second, and third, etc. does not indicate any order. These words may be interpreted as names. The steps in the above embodiments, unless otherwise specified, should not be understood as limitations on the order of execution.

Claims

1. A method for calculating radial velocity of a fractured reservoir, characterized in that: Methods include: Obtain the original image of the radial section after fracturing; Processing the original image of the radial section to obtain a crack picking result; According to the crack picking results, the fractal dimensions of the coverage ranges of different radii are calculated, and the crack densities of different radii are calculated according to the fractal dimensions; The crack density is proportional to the fractal dimension; Calculate the corresponding radial velocity according to the fracture density of different radii and the drilling data of the fractured formation; the radial velocity includes the shear wave radial velocity and the longitudinal wave radial velocity; The processing of the radial section original image to obtain the crack picking result further includes: Performing perspective stretching and grayscale processing on the original image of the radial section to obtain an image digital matrix of the original image of the radial section; Obtaining an enhanced image matrix according to the image digital matrix and the Hessian matrix of the original section image; Performing convolution processing on the enhanced image matrix according to a preset operator to obtain a crack boundary; Based on the crack boundary, cracks with crack widths greater than a preset width threshold are subjected to expansion corrosion processing to obtain crack picking results.

2. The method according to claim 1, characterized in that The step of obtaining an enhanced image matrix according to the image digital matrix and the Hessian matrix of the original cross-sectional image further comprises: Constructing a Gaussian function according to the scale factor, and performing convolution processing with the image digital matrix to obtain a scale space derivative; Determine a Hessian matrix of the original profile image according to the scale-space derivative, and determine a two-dimensional linear filter according to the eigenvalues ​​of the Hessian matrix; An enhanced image matrix is ​​obtained by multiplying the maximum value of the two-dimensional linear filter by the scale factor; wherein the scale factor matches the crack track broadband of the original profile image.

3. The method according to claim 1, characterized in that The step of calculating the fractal dimensions of coverage areas of different radii according to the crack picking results, and calculating the crack densities of different radii according to the fractal dimensions further comprises: Determine the borehole radius of the radial section original image, and set the borehole radius as the initial radius; Taking the wellbore as the center, determine the number of pixels or bits covering the cracks within the coverage range of the initial radius, and obtain the fractal dimension of the coverage range of the initial radius according to the number of pixels or bits; increase the initial radius by a preset exponential to obtain a new radius, calculate the fractal dimension of the coverage range of the new radius, and repeatedly update the radius until the coverage range of the radius covers the original image of the radial section; The crack density of each radius is calculated based on the fractal dimension of the coverage range of each radius and the preset scale factor.

4. The method according to claim 1, characterized in that: The calculating of the corresponding radial velocity according to the fracture density of different radii and the drilling data of the fractured formation further comprises: The radial velocity of longitudinal waves is calculated based on the density of saturated rock, equivalent seepage density, density of pore fluid, storage modulus of porous fracture medium, low-frequency P-wave modulus and modulus of saturated rock; among which, the storage modulus of porous fracture medium is obtained based on the fracture density of different radii; The radial velocity of shear waves is calculated based on the density of saturated rock, equivalent seepage density, density of pore fluid and shear modulus of saturated rock; the shear modulus of saturated rock is obtained based on the storage modulus of porous fracture medium.

5. The method according to any one of claims 1 to 4, characterized in that The radial section original image includes main seam type fractures and network type fractures.

6. A device for calculating radial velocity of a fractured reservoir, characterized in that: The device includes: An image module, suitable for obtaining the original image of the radial section after fracturing; A crack picking module, adapted to process the original radial section image to obtain a crack picking result; A crack density module, adapted to calculate the fractal dimensions of coverage areas of different radii according to the crack picking results, and calculate crack densities of different radii according to the fractal dimensions; The crack density is proportional to the fractal dimension; A radial velocity module, adapted to calculate the corresponding radial velocity according to the fracture density of different radii and the drilling data of the fractured formation; the radial velocity includes the shear wave radial velocity and the longitudinal wave radial velocity; The crack picking module is further adapted to: Performing perspective stretching and grayscale processing on the original image of the radial section to obtain an image digital matrix of the original image of the radial section; Obtaining an enhanced image matrix according to the image digital matrix and the Hessian matrix of the original section image; Performing convolution processing on the enhanced image matrix according to a preset operator to obtain a crack boundary; Based on the crack boundary, cracks with crack widths greater than a preset width threshold are subjected to expansion corrosion processing to obtain crack picking results.

7. A computing device, characterized in that include: A processor, a memory, a communication interface and a communication bus, wherein the processor, the memory and the communication interface communicate with each other via the communication bus; The memory is used to store at least one executable instruction, and the executable instruction enables the processor to perform operations corresponding to the method for calculating the radial velocity of a fractured reservoir according to any one of claims 1-5.

8. A computer storage medium, characterized in that: The storage medium stores at least one executable instruction, and the executable instruction enables the processor to execute operations corresponding to the method for calculating the radial velocity of a fractured reservoir according to any one of claims 1-5.

9. A computer program product, characterized in that The method comprises at least one executable instruction, wherein the executable instruction enables a processor to execute operations corresponding to the method for calculating radial velocity of a fractured reservoir according to any one of claims 1 to 5.

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