A reservoir parameter determination method and device, computer equipment and readable medium

Abstract

The present specification relates to the technical field of reservoir parameter estimation, and particularly relates to a reservoir parameter determination method and device, computer equipment and readable medium. The reservoir parameter determination method comprises: determining orthogonal medium anisotropy parameters, a low-frequency initial model and a mixed phase wavelet based on logging data and seismic data; performing combination update on a preset orthogonal medium longitudinal wave reflection formula to obtain a target longitudinal wave reflection formula; constructing a minimum target function based on the orthogonal medium anisotropy parameters, the low-frequency initial model and the mixed phase wavelet; and solving the target longitudinal wave reflection formula based on the minimum target function and the seismic data to obtain target reservoir parameters. By using the embodiments of the present specification, the solving stability and accuracy of the reservoir parameters are improved simultaneously in the orthogonal anisotropic medium based on the updated target longitudinal wave reflection formula and the minimum target function.

Description

Technical Field

[0001] This specification relates to the field of reservoir parameter estimation technology, and in particular to a method, apparatus, computer equipment, and readable medium for determining reservoir parameters. Background Technology

[0002] Currently, parameters used to describe reservoirs include elastic parameters and anisotropic parameters, which are important methods for characterizing reservoir features and predicting subsurface fractures. When determining reservoir parameters, a pre-defined orthogonal medium P-wave reflection formula is used for solution; this method improves stability at the cost of accuracy. To simultaneously improve stability and accuracy, the assumption of solving in isotropic media is often made. While this improves stability and some accuracy, current seismic waves propagate in orthogonally anisotropic media, resulting in lower accuracy compared to real-world conditions.

[0003] How to simultaneously improve the stability and accuracy of reservoir parameter solutions in orthotropic media is a problem that urgently needs to be solved in the current technology. Summary of the Invention

[0004] To address the problems in the prior art, embodiments of this specification provide a method, apparatus, computer device, and readable medium for determining reservoir parameters, which simultaneously improves the stability and accuracy of reservoir parameter solutions in orthotropic media.

[0005] To solve the above-mentioned technical problems, the specific technical solution in this specification is as follows:

[0006] On the one hand, the embodiments of this specification provide a method for determining reservoir parameters, including,

[0007] Based on well logging and seismic data, the anisotropic parameters of the orthogonal medium, the low-frequency initial model, and the mixed phase wavelet were determined.

[0008] The target longitudinal wave reflection formula is obtained by combining and updating the preset orthogonal medium longitudinal wave reflection formula.

[0009] Based on the orthogonal medium anisotropy parameters, the low-frequency initial model, and the mixed phase wavelet, a minimum objective function is constructed; and

[0010] Based on the minimum objective function and the seismic data, the target P-wave reflection formula is solved to obtain the target reservoir parameters.

[0011] Furthermore, based on well logging and seismic data, the determination of the mixed phase wavelet further includes,

[0012] Based on the well logging data, the fracture orientation was determined;

[0013] From the seismic data, determine the target seismic data corresponding to the fracture orientation; and

[0014] Based on the target seismic data, the hybrid phase wavelet is determined.

[0015] Furthermore, the method of combining and updating the preset orthogonal medium longitudinal wave reflection formula to obtain the target longitudinal wave reflection formula further includes,

[0016] The formula for the reflection coefficient of the crack in the pre-set orthogonal medium is simplified to obtain the formula for the reflection coefficient of the crack in the target orthogonal medium; and

[0017] Based on the target orthogonal medium crack disturbance reflection coefficient formula and the preset transverse isotropic longitudinal wave reflection coefficient formula in the preset orthogonal medium longitudinal wave reflection formula, the target longitudinal wave reflection formula is determined.

[0018] Furthermore, the formula for the reflection coefficient of the crack disturbance in the target orthogonal medium further includes,

[0019]

[0020] Wherein, θ represents the incident angle, φ represents the azimuth angle relative to the crack normal plane, D = Γ2 - Γ1, and E = ε (2) -ε (1 ), the Γ2=(δ (2) -8g 2 γ (2) ),Γ1=(δ (1) -8g 2 γ (1) ), where ε represents the longitudinal wave anisotropy parameter, δ represents the second derivative of the longitudinal wave phase velocity function at perpendicular incidence, g represents the square term of the transverse-longitudinal wave velocity ratio, and γ represents the transverse wave anisotropy parameter.

[0021] Furthermore, the target P-wave reflection formula further includes,

[0022]

[0023] Among them, the The formula characterizing the preset transversely isotropic longitudinal wave reflection coefficient, the The formula characterizing the reflection coefficient of the target orthogonal medium crack disturbance, where θ represents the incident angle, φ represents the azimuth angle relative to the crack normal plane, and A = ρα, is used. The The ρ characterizes the density, the ε characterizes the longitudinal wave anisotropy parameter, the δ characterizes the second derivative of the longitudinal wave phase velocity function at perpendicular incidence, the g characterizes the square term of the transverse-longitudinal wave velocity ratio, the γ characterizes the transverse wave anisotropy parameter, the α characterizes the longitudinal wave velocity, and the K characterizes the square term of four times the transverse-longitudinal wave velocity ratio.

[0024] Furthermore, the minimum objective function further includes,

[0025]

[0026] Wherein, d represents seismic data, G represents the linear forward modeling operator determined based on the hybrid phase wavelet, and m prior The prior information of the model parameter vector determined based on the low-frequency initial model is represented, and m represents the target reservoir parameters.

[0027] Furthermore, the target reservoir parameters include acoustic impedance, anisotropic shear modulus, P-wave phase velocity along the fracture strike direction, azimuth anisotropic gradient, and relative fracture density. The process of solving the target P-wave reflection formula based on the minimum objective function and the seismic data to obtain the target reservoir parameters further includes...

[0028] Based on the minimum objective function, the target longitudinal wave reflection formula is solved to obtain the acoustic impedance, the anisotropic shear modulus, and the longitudinal wave phase velocity along the crack direction.

[0029] Determine the difference in seismic amplitude between the first residual sub-seismic data (excluding the fracture direction) corresponding to the observation azimuth in the seismic data and the second residual sub-seismic data parallel to the fracture direction;

[0030] Based on the minimum objective function and the seismic amplitude difference, the azimuth anisotropy gradient and the relative crack density are determined.

[0031] On the other hand, embodiments of this specification also provide a method for determining reservoir parameters, including,

[0032] The first determining unit is used to determine the anisotropy parameters of the orthogonal medium, the low-frequency initial model, and the mixed phase wavelet based on well logging data and seismic data.

[0033] The update unit is used to combine and update the preset orthogonal medium longitudinal wave reflection formula to obtain the target longitudinal wave reflection formula.

[0034] The construction unit is used to construct a minimum objective function based on the orthogonal medium anisotropy parameters, the low-frequency initial model, and the mixed phase wavelet; and

[0035] The solution unit is used to solve the target P-wave reflection formula based on the minimum objective function and the seismic data to obtain the target reservoir parameters.

[0036] On the other hand, embodiments of this specification also provide a computer device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the above-described method.

[0037] On the other hand, embodiments of this specification also provide a computer-readable storage medium having computer instructions stored thereon, which, when executed by a processor, implement the above-described method.

[0038] Using the embodiments in this specification, based on received well logging data and seismic data, the anisotropic parameters of the orthogonal medium, the low-frequency initial model, and the mixed-phase wavelet are determined. A preset orthogonal medium P-wave reflection formula is obtained, and this preset orthogonal medium P-wave reflection formula is combined and updated to obtain the target P-wave reflection formula. Based on the determined orthogonal medium anisotropic parameters, the low-frequency initial model, and the mixed-phase wavelet, a minimum objective function is constructed. Then, based on the minimum objective function and seismic data, the target P-wave reflection formula is solved to obtain the target reservoir parameters. This achieves the combined updating of the preset orthogonal medium P-wave reflection formula (which can be solved in weakly anisotropic media) to obtain a target P-wave reflection formula applicable to orthogonal anisotropic media. Furthermore, based on the orthogonal medium anisotropic parameters, the low-frequency initial model, and the mixed-phase wavelet, a minimum objective function is constructed to solve the target P-wave reflection formula, thereby determining the target reservoir parameters. This achieves both improved stability and accuracy in solving reservoir parameters in orthogonal anisotropic media. Attached Figure Description

[0039] To more clearly illustrate the technical solutions in the embodiments or prior art of this specification, the drawings used in the description of the embodiments or prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this specification. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0040] Figure 1 The figure shown is a schematic diagram of an implementation system for a reservoir parameter determination method according to an embodiment of this specification;

[0041] Figure 2 The diagram shown is a flowchart of a method for determining reservoir parameters according to an embodiment of this specification.

[0042] Figure 3 The diagram shown is a flowchart of a hybrid phase wavelet determination method according to an embodiment of this specification;

[0043] Figure 4 The diagram shown is a flowchart of a method for determining the longitudinal wave reflection formula of a target according to an embodiment of this specification;

[0044] Figure 5A The diagram shown is a schematic representation of a seismic wavelet corresponding to seismic data at different azimuth angles according to an embodiment of this specification.

[0045] Figure 5B The diagram shown is a schematic representation of well logging data from an embodiment of this specification.

[0046] Figure 5C The diagram shown is a noise-free synthetic seismic azimuth gather according to an embodiment of this specification.

[0047] Figure 5D The diagram shown is a schematic diagram of a first target reservoir parameter set according to an embodiment of this specification;

[0048] Figure 5E The diagram shown is a schematic diagram of a second target reservoir parameter set according to an embodiment of this specification;

[0049] Figure 5F The diagram shown is a schematic diagram of a target reservoir parameter set according to an embodiment of this specification;

[0050] Figure 6 The diagram shown is a structural schematic of a reservoir parameter determination device according to an embodiment of this specification.

[0051] Figure 7 This is a schematic diagram of the structure of a computer device according to an embodiment of this specification.

[0052] [Explanation of Labels in the Attached Image]

[0053] 101. User terminal;

[0054] 102. Server;

[0055] 501. AC parameter diagram;

[0056] 502. AB parameter diagram;

[0057] 503, D parameter diagram;

[0058] 504, E-parameter diagram;

[0059] 610. First Determined Unit;

[0060] 620. Update Unit;

[0061] 630. Building Unit;

[0062] 640. Solve the element;

[0063] 702. Computer equipment;

[0064] 704. Processing equipment;

[0065] 706. Storage resources;

[0066] 708. Drive mechanism;

[0067] 710. Input / Output Module;

[0068] 712. Input devices;

[0069] 714. Output devices;

[0070] 716. Presentation equipment;

[0071] 718. Graphical User Interface;

[0072] 720. Network interface;

[0073] 722. Communication link;

[0074] 724. Communication bus. Detailed Implementation

[0075] The technical solutions in the embodiments of this specification will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this specification, and not all embodiments. Based on the embodiments in this specification, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this specification.

[0076] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, apparatus, product, or device that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or devices.

[0077] It should be noted that the steps shown in the flowchart in the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions, and although a logical order is shown in the flowchart, in some cases the steps shown or described may be executed in a different order than that shown here.

[0078] Figure 1 The diagram illustrates an implementation system for a reservoir parameter determination method according to an embodiment of this specification. The system may include a user terminal 101 and a server 102, which communicate via a network. This network may include a Local Area Network (LAN), a Wide Area Network (WAN), the Internet, or a combination thereof, and is connected to a website, user equipment (e.g., a computing device), and a backend system. Upon receiving well logging data and seismic data, the server 102 determines orthogonal anisotropy parameters, a low-frequency initial model, and a mixed-phase wavelet based on the well logging data and seismic data. It then updates the preset orthogonal medium P-wave reflection formula to obtain a target P-wave reflection formula. Based on the orthogonal medium anisotropy parameters, the low-frequency initial model, and the mixed-phase wavelet, it constructs a minimum objective function. Finally, based on the minimum objective function and the seismic data, it solves the target P-wave reflection formula to obtain the target reservoir parameters, which are then sent to the user terminal 101. In addition, it may include, for example, a data acquisition terminal, which can be a sensor or other device capable of acquiring well logging data and transmitting the well logging data to a server, thereby realizing the acquisition and transmission of well logging data. The data acquisition terminal and the server can communicate, for example, via a network.

[0079] Alternatively, server 102 may be a node of a cloud computing system (not shown in the figure), or each server 102 may be a separate cloud computing system comprising multiple computers interconnected by a network and operating as a distributed processing system.

[0080] In an optional embodiment, the user terminal 101 may include electronic devices, including but not limited to smartphones, data acquisition devices, desktop computers, tablets, laptops, smart speakers, digital assistants, augmented reality (AR) / virtual reality (VR) devices, smart wearable devices, and other similar electronic devices. Optionally, the operating system running on the electronic device may include, but is not limited to, Android, iOS, Linux, Windows, etc.

[0081] In addition, it should be noted that, Figure 1 The example shown is merely one application environment provided in this manual. In actual applications, it may include multiple user terminals 101, and this manual does not impose any restrictions.

[0082] Figure 2The diagram shows a flowchart of a method for determining reservoir parameters according to an embodiment of this specification. The process of determining reservoir parameters is described in this figure, but based on conventional or non-inventive methods, it may include more or fewer operational steps. The order of steps listed in the embodiment is merely one possible execution order among many and does not represent the only possible execution order. In actual system or device products, the methods shown in the embodiment or the accompanying drawings can be executed sequentially or in parallel. Specifically, as shown... Figure 2 As shown, the method may include:

[0083] S210, based on well logging data and seismic data, determines the anisotropic parameters of orthogonal media, the low-frequency initial model, and the mixed phase wavelet;

[0084] S220, The preset orthogonal medium longitudinal wave reflection formula is combined and updated to obtain the target longitudinal wave reflection formula;

[0085] S230, based on orthogonal medium anisotropic parameters, low-frequency initial model and mixed phase wavelet, constructs a minimum objective function;

[0086] S240, based on the minimum objective function and seismic data, solves the target P-wave reflection formula to obtain the target reservoir parameters.

[0087] Using the embodiments in this specification, based on received well logging data and seismic data, the anisotropic parameters of the orthogonal medium, the low-frequency initial model, and the mixed-phase wavelet are determined. A preset orthogonal medium P-wave reflection formula is obtained, and this preset orthogonal medium P-wave reflection formula is combined and updated to obtain the target P-wave reflection formula. Based on the determined orthogonal medium anisotropic parameters, the low-frequency initial model, and the mixed-phase wavelet, a minimum objective function is constructed. Then, based on the minimum objective function and seismic data, the target P-wave reflection formula is solved to obtain the target reservoir parameters. This achieves the combined updating of the preset orthogonal medium P-wave reflection formula (which can be solved in weakly anisotropic media) to obtain a target P-wave reflection formula applicable to orthogonal anisotropic media. Furthermore, based on the orthogonal medium anisotropic parameters, the low-frequency initial model, and the mixed-phase wavelet, a minimum objective function is constructed to solve the target P-wave reflection formula, thereby determining the target reservoir parameters. This achieves both improved stability and accuracy in solving reservoir parameters in orthogonal anisotropic media.

[0088] According to one embodiment of this specification, the well logging data is downhole data acquired using well logging instruments such as sensors. The seismic data is data acquired using a seismic signal receiving system and a seismic information recording system.

[0089] Based on well logging data and seismic data, the anisotropic parameters of orthogonal media, low-frequency initial model, and mixed phase wavelet are determined. Specifically, the anisotropic parameters of orthogonal media are determined by performing time-depth conversion processing on the well logging data to obtain first processed well logging data, and then performing orthogonal anisotropic media rock physics modeling processing on the first processed well logging data to obtain the anisotropic parameters of the orthogonal media.

[0090] Based on well logging and seismic data, the anisotropy parameters of the orthogonal medium, the low-frequency initial model, and the mixed phase wavelet are determined. Specifically, the low-frequency initial model is determined by extrapolating from the well logging data under the constraints of seismic horizon data determined by the seismic data. It should be noted that the low-frequency initial model can be determined by extrapolating from either well logging data or coarsened well logging data.

[0091] Based on well logging and seismic data, the anisotropy parameters of the orthogonal medium, the low-frequency initial model, and the mixed phase wavelet are determined. Specifically, the mixed phase wavelet is determined by identifying the target seismic data corresponding to the well logging data from the seismic data, and then determining the mixed phase wavelet based on this target seismic data. This mixed phase wavelet can, for example, be a mixed wavelet extracted from the incident angle seismic data at different azimuth angles in the well logging bypass.

[0092] The pre-defined formula for longitudinal wave reflection in orthogonal media can be, for example, as shown in formula (1) below.

[0093]

[0094] Where ρ represents density, α represents P-wave velocity, β represents the seventh parameter, Δ refers to the difference between two adjacent layers above and below the interface, ˉ refers to the average value of the seismic wave passing through two adjacent layers of the interface, θ represents the incident angle, δ represents the second derivative of the P-wave phase velocity function when incident perpendicularly, ε represents the P-wave anisotropy parameter, φ represents the azimuth angle relative to the crack normal plane, γ represents the S-wave anisotropy parameter, g represents the square term of the P-wave velocity ratio, and...

[0095] A ij =C ij / ρ is the density-normalized elastic stiffness coefficient of the orthotropic medium.

[0096] It should be noted that the longitudinal wave velocity and the seventh parameter are the vertical longitudinal wave velocity and vertical transverse wave velocity of the isotropic medium, respectively. The square term of the transverse-longitudinal wave velocity ratio is specifically...

[0097] The target P-wave reflection formula is obtained by combining and updating the preset orthogonal medium P-wave reflection formula. Specifically, the preset orthogonal medium P-wave reflection formula is separated and updated into a preset transverse isotropic P-wave reflection coefficient formula and a preset orthogonal medium crack disturbance reflection coefficient formula. An optimization term is determined from the preset transverse isotropic P-wave reflection coefficient formula and the preset orthogonal medium crack disturbance reflection coefficient formula. The optimization term is then optimized to obtain the target P-wave reflection formula.

[0098] The minimum objective function is constructed using a pre-defined objective function within the Bayesian framework as a template. Specifically, based on the orthogonal medium anisotropic parameters, the low-frequency initial model, and the mixed-phase wavelet, the minimum objective function is constructed by obtaining the pre-defined objective function within the Bayesian framework and then filling it with the orthogonal medium anisotropic parameters, the low-frequency initial model, and the mixed-phase wavelet to obtain the minimum objective function. More specifically, the prior model distribution and likelihood function in this minimized objective function both follow a Gaussian distribution.

[0099] After determining the target P-wave reflection formula and the minimum objective function, the target P-wave reflection formula is solved based on the minimum objective function and seismic data to obtain the target reservoir parameters. Specifically, the first target reservoir parameter is obtained by solving the target P-wave reflection formula based on the minimum objective function. Then, updated seismic data is determined based on the seismic data. The second target reservoir parameter is obtained by solving the target P-wave reflection formula based on the minimum objective function and the updated seismic data. The target reservoir parameter is determined by the first and second target reservoir parameters.

[0100] According to another embodiment of this specification, the minimum objective function can be, for example, as shown in the following formula (2).

[0101]

[0102] Where d represents seismic data, G represents the linear forward modeling operator determined based on the mixed phase wavelet, and m prior The prior information of the model parameter vector determined based on the low-frequency initial model is represented, and m represents the target reservoir parameters.

[0103] The target reservoir parameters follow a Gaussian distribution. Where μ m ∑ represents the prior average (mean of well logging data). m This is the prior covariance matrix determined based on the anisotropic parameters of orthogonal media. The correlation between the inverted parameters is estimated using a multivariate Gaussian distribution. ∑ d It is the noise covariance diagonal matrix, assuming the noise in the observed data is uncorrelated. in It is the noise variance, which follows a zero-mean Gaussian distribution.

[0104] Taking the derivative of the above formula (2), we obtain the inversion result, as shown in the following formula (3).

[0105]

[0106] Where m represents the target reservoir parameters, G represents the linear forward modeling operator determined based on the hybrid phase wavelet, d represents the seismic data, and m prior It represents the prior information of the model parameter vector determined based on the low-frequency initial model.

[0107] Furthermore, based on the minimum objective function and seismic data, the target P-wave reflection formula is solved to obtain the target reservoir parameters. Specifically, based on the above inversion result formula (3) and seismic data, the target P-wave reflection formula is solved to obtain the target reservoir parameters.

[0108] Figure 3 The diagram shows a flowchart of a hybrid phase wavelet determination method according to an embodiment of this specification. While this diagram depicts a hybrid phase wavelet determination process, it can include more or fewer operational steps based on conventional or non-inventive methods. Specifically, as shown... Figure 3 As shown, the method may include:

[0109] S311, based on well logging data, determines the fracture orientation;

[0110] S312, from the seismic data, determine the target seismic data corresponding to the fracture orientation;

[0111] S313, based on target seismic data, determine the mixed phase wavelet.

[0112] According to another embodiment of this specification, electrical imaging logging data is used to determine the orientation of wellbore fractures characterized by the logging data, and this orientation is taken as the fracture orientation.

[0113] From the seismic data and the data corresponding to each of the three planes, sub-target seismic data corresponding to the fracture orientation are determined, and these three sub-target seismic data are then combined to obtain the target seismic data. The three planes are three mutually perpendicular surfaces in a three-dimensional plane.

[0114] After determining the target seismic data, wavelets with different azimuth angles are extracted and mixed from the target seismic data to obtain mixed phase wavelets.

[0115] Figure 4The diagram shows a flowchart of a method for determining a target P-wave reflection formula according to an embodiment of this specification. This figure describes a process for determining a target P-wave reflection formula, but based on conventional or non-inventive methods, it may include more or fewer operational steps. Specifically, as shown... Figure 4 As shown, the method may include:

[0116] S421, The formula for the reflection coefficient of crack disturbance in the preset orthogonal medium is simplified to obtain the formula for the reflection coefficient of crack disturbance in the target orthogonal medium.

[0117] S422, Based on the target orthogonal medium crack disturbance reflection coefficient formula and the preset transverse isotropic longitudinal wave reflection coefficient formula in the preset orthogonal medium longitudinal wave reflection formula, the target longitudinal wave reflection formula is determined.

[0118] According to another embodiment of this specification, the preset orthogonal medium longitudinal wave reflection formula is separated and recombined to obtain a preset transversely isotropic longitudinal wave reflection coefficient formula and a preset orthogonal medium crack disturbance reflection coefficient formula. Specifically, the above formula (1) is separated and recombined to obtain the preset transversely isotropic longitudinal wave reflection coefficient formula as shown in the following formula (4) and the preset orthogonal medium crack disturbance reflection coefficient formula as shown in the following formula (5). It should be noted that it is precisely by combining the anisotropic parameters that represent the same information and then splitting the two formulas that the weak anisotropy of the original formula (1) is enhanced.

[0119]

[0120] Where ρ represents density, α represents P-wave velocity, β represents the seventh parameter, Δ refers to the difference between two adjacent layers above and below the interface, ˉ refers to the average value of the seismic wave passing through two adjacent layers of the interface, θ represents the incident angle, ε represents the P-wave anisotropy parameter, γ represents the S-wave anisotropy parameter, and g represents the square term of the P-wave velocity ratio.

[0121]

[0122] Where △ refers to the difference between two adjacent layers above and below the interface, θ represents the incident angle, δ represents the second derivative of the P-wave phase velocity function when incident perpendicularly, ε represents the P-wave anisotropy parameter, φ represents the azimuth angle relative to the crack normal plane, γ represents the shear wave anisotropy parameter, and g represents the square term of the P-wave velocity ratio.

[0123] Further updating formula (4) yields the following formula (6).

[0124]

[0125] Where A = ρα, as well as

[0126] The formula for the reflection coefficient of the crack in the pre-set orthogonal medium is simplified to obtain the formula for the reflection coefficient of the crack in the target orthogonal medium. Specifically, the sin in formula (3) above is deleted. 2 φcos 2 φ, thus obtaining the formula for the reflection coefficient of the crack disturbance in the target orthogonal medium. It should be noted that, due to sin... 2 φcos 2 Since φ≦0.25, the effect of this term on any azimuth angle can be ignored, so this term can be deleted.

[0127] After obtaining the target orthogonal medium crack disturbance reflection coefficient formula, the target orthogonal medium crack disturbance reflection coefficient formula and the preset transverse isotropic longitudinal wave reflection coefficient formula are used to form the target longitudinal wave reflection formula.

[0128] According to another embodiment of this specification, the formula for the target orthogonal medium crack disturbance reflection coefficient after deletion is shown in the following formula (7).

[0129]

[0130] Where θ represents the incident angle, φ represents the azimuth angle relative to the crack normal plane, D = Γ2 - Γ1, E = ε (2) -ε (1) Γ2=(δ (2) -8g 2 γ (2) ),Γ1=(δ (1) -8g 2 γ (1) ), where ε represents the anisotropy parameter of the longitudinal wave, δ represents the second derivative of the longitudinal wave phase velocity function when the wave is perpendicularly incident, g represents the square term of the longitudinal-transverse wave velocity ratio, and γ represents the anisotropy parameter of the transverse wave.

[0131] According to another embodiment of this specification, the target longitudinal wave reflection formula after deletion and combination can be, for example, as shown in the following formula (8).

[0132]

[0133] in, The formula characterizing the reflection coefficient of a transversely isotropic longitudinal wave is given. The formula for the reflection coefficient of a crack in an orthogonal medium is given, where θ represents the incident angle, φ represents the azimuth angle relative to the crack's normal plane, and A = ρα. ρ represents density, ε represents the P-wave anisotropy parameter, δ represents the second derivative of the P-wave phase velocity function at perpendicular incidence, g represents the square term of the P-wave velocity ratio, γ represents the P-wave anisotropy parameter, α represents the P-wave velocity, and K represents the square term of a four-fold P-wave velocity ratio.

[0134] As can be seen from formula (8), the target P-wave reflection formula after combination update has five reservoir parameters, namely A (acoustic impedance), B (anisotropic shear modulus), C (P-wave phase velocity along the fracture strike direction), D (azimuth anisotropic gradient) and E (relative fracture density). A, B and C are only related to the incident angle, while D and E are related to both the incident angle and the azimuth angle.

[0135] Figure 5A The diagram shown is a schematic representation of a seismic wavelet corresponding to seismic data at different azimuth angles according to an embodiment of this specification. Figure 5B The diagram shown is a schematic representation of well logging data from an embodiment of this specification. Figure 5C The diagram shown is a noise-free synthetic seismic azimuth gather according to an embodiment of this specification. Figure 5D The diagram shown is a schematic diagram of a first target reservoir parameter set according to an embodiment of this specification; Figure 5E The diagram shown is a schematic diagram of a second target reservoir parameter set according to an embodiment of this specification; Figure 5F The diagram shown is a schematic diagram of a target reservoir parameter set according to an embodiment of this specification.

[0136] According to another embodiment of this specification, the target storage parameters include acoustic impedance, anisotropic shear modulus, P-wave phase velocity along the fracture strike direction, azimuth anisotropy gradient, and relative fracture density. Based on the minimum objective function and seismic data, the target P-wave reflection formula is solved to obtain the target reservoir parameters, including: solving the target P-wave reflection formula based on the minimum objective function to obtain the acoustic impedance, anisotropic shear modulus, and P-wave phase velocity along the fracture strike direction; determining the seismic amplitude difference between the first residual sub-seismic data corresponding to the observed azimuth (excluding the fracture strike) and the second residual sub-seismic data parallel to the fracture strike in the seismic data; and determining the azimuth anisotropy gradient and relative fracture density based on the minimum objective function and the seismic amplitude difference.

[0137] Based on the minimum objective function, the target longitudinal wave reflection formula is solved to obtain the acoustic impedance, anisotropic shear modulus and longitudinal wave phase velocity along the crack direction. For example, the derivative of the above formula (2) is used to obtain the inversion result, as shown in the above formula (3).

[0138] Based on the above formula (3), the target P-wave reflection formula is inverted to obtain the acoustic impedance, anisotropic shear modulus, and P-wave phase velocity along the fracture direction. It should be noted that when inverting to solve for the acoustic impedance, anisotropic shear modulus, and P-wave phase velocity along the fracture direction, d in formula (3) represents the amplitude data extending along the [x2, x3] plane in the three planes of the seismic data. The process of determining the amplitude data extending along the [x2, x3] plane specifically involves determining the fracture orientation corresponding to the well logging data, and then determining the amplitude data corresponding to that fracture orientation from the data corresponding to the [x2, x3] plane in the three planes of the seismic data. Therefore, m = [A, B, C] is obtained. T This allows for the determination of acoustic impedance, anisotropic shear modulus, and longitudinal wave phase velocity along the crack direction.

[0139] Because a large offset incident angle gather parallel to the fracture strike was used for azimuth-independent three-term synchronous inversion, the azimuth-independent three-term approximation not only maintains a similar degree of approximation to the Ruger formula and the exact formula at each offset, but also can synchronously invert the AVO intercept term, gradient term, and anisotropic velocity term, rather than the gradient of changes in properties between strata, thus demonstrating good interpretability in shale gas reservoir characterization.

[0140] Based on the seismic data, the above formula (3) is updated to obtain the updated formula (3). Specifically, the above formula (3) is updated by using the difference between the observed azimuth amplitude data (i.e., data other than the fracture direction) and the amplitude data parallel to the fracture direction in the seismic data to update d in formula (3), thus obtaining the updated formula (3). Based on the updated formula (3), the target P-wave reflection formula is inverted to obtain the azimuth anisotropy gradient and relative fracture density.

[0141] After determining five target reservoir parameters (acoustic impedance, anisotropic shear modulus, P-wave phase velocity along fracture strike, azimuth anisotropy gradient, and relative fracture density), reservoir characterization information can be determined based on this information. For example, the parameter combination AC (acoustic impedance - P-wave phase velocity along fracture strike) can be used to distinguish brittle-related shale from surrounding strata, while the parameter combination AB (acoustic impedance - anisotropic shear modulus) can successfully identify TOC-rich shale. High-TOC shale gas reservoirs exhibit low A and low B values, while brittle shale exhibits low A and low C values. Parameter D quantifies the azimuth anisotropy at small to medium offsets and, because it is positively correlated with fracture density, is often used to represent relative fracture density or horizontal stress anisotropy. Parameter E (relative fracture density) characterizes the difference in P-wave velocity along the x1-x2 direction, which depends not only on fracture density but also on the fluid filling the fractures.

[0142] For example, the collected data are as follows: Figure 5A The seismic wavelets corresponding to the seismic data at different azimuth angles shown are as follows: Figure 5B The well logging data shown. Denoising was performed on the seismic data from different azimuths to obtain the following results: Figure 5C The noise-free synthetic seismic azimuth gather is shown. Furthermore, based on... Figure 5B Given the data, a minimum objective function is determined. Using the minimum objective function and seismic data, an inversion solution is performed on the target P-wave reflection formula to obtain the first target reservoir parameters (acoustic impedance, anisotropic shear modulus, and P-wave phase velocity along the fracture strike) and the second target reservoir parameters (azimuth anisotropy gradient and relative fracture density). The specific first target reservoir parameters are as follows: Figure 5D As shown, the solid line represents the actual well logging data from the noise-free synthetic data, the dashed line represents the initial model, and the dotted line represents the parameters of the first target reservoir. The parameters of the second target reservoir are as follows... Figure 5E As shown, the solid line represents the actual well logging data of the noise-free synthetic data, the dashed line represents the initial model, and the dotted line represents the parameters of the second target reservoir.

[0143] Analyzing the determined parameters of the first and second target reservoirs, we constructed parameter diagrams 501 (AC), 502 (AB), 503 (D), and 504 (E) to identify brittle-related shale, TOC-rich shale, and to quantify the azimuth anisotropy of small-scale shifts and the difference in P-wave velocity along the x1-x2 direction. It should be noted that the coordinates of the lithofacies portion in AC and AB parameter diagrams 501 and 502 represent ductile shale, brittle shale, and limestone, respectively.

[0144] Figure 6 The diagram shown is a structural schematic of a reservoir parameter determination device according to an embodiment of this specification. Figure 6 As shown, including,

[0145] The first determining unit 610 is used to determine the anisotropy parameters of the orthogonal medium, the low-frequency initial model, and the mixed phase wavelet based on well logging data and seismic data.

[0146] The update unit 620 is used to perform a combined update on the preset orthogonal medium longitudinal wave reflection formula to obtain the target longitudinal wave reflection formula.

[0147] Building element 630 is used to construct a minimum objective function based on orthogonal medium anisotropy parameters, a low-frequency initial model, and a mixed phase wavelet; and

[0148] Solver 640 is used to solve the target P-wave reflection formula based on the minimum objective function and seismic data to obtain the target reservoir parameters.

[0149] Since the principle of the above-mentioned device in solving the problem is similar to that of the above-mentioned method, the implementation of the above-mentioned device can refer to the implementation of the above-mentioned method, and the repeated parts will not be described again.

[0150] like Figure 7 The diagram illustrates the structure of a computer device according to an embodiment of this specification. The apparatus described in this specification can be the computer device in this embodiment, performing the methods described above. The computer device 702 may include one or more processing devices 704, such as one or more central processing units (CPUs), each of which can implement one or more hardware threads. The computer device 702 may also include any storage resource 706 for storing information of any kind, such as code, settings, data, etc. Without limitation, for example, the storage resource 706 may include any one or more combinations of the following: any type of RAM, any type of ROM, flash memory, hard disk, optical disk, etc. More generally, any storage resource can use any technology to store information. Furthermore, any storage resource can provide volatile or non-volatile retention of information. Further, any storage resource may represent a fixed or removable component of the computer device 702. In one case, when the processing device 704 executes associated instructions stored in any storage resource or combination of storage resources, the computer device 702 can perform any operation of the associated instructions. The computer device 702 also includes one or more drive mechanisms 708 for interacting with any storage resource, such as a hard disk drive mechanism, an optical disk drive mechanism, etc.

[0151] Computer device 702 may also include an input / output module 710 (I / O) for receiving various inputs (via input device 712) and providing various outputs (via output device 714). A specific output mechanism may include a presentation device 716 and an associated graphical user interface (GUI) 718. In other embodiments, the input / output module 710 (I / O), input device 712, and output device 714 may be omitted, and the device may function solely as a computer device within a network. Computer device 702 may also include one or more network interfaces 720 for exchanging data with other devices via one or more communication links 722. One or more communication buses 724 couple the components described above together.

[0152] Communication link 722 can be implemented in any way, such as via a local area network, a wide area network (e.g., the Internet), a point-to-point connection, or any combination thereof. Communication link 722 may include any combination of hardwired links, wireless links, routers, gateway functions, name servers, etc., governed by any protocol or combination of protocols.

[0153] This specification also provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the above-described method.

[0154] This specification also provides a computer program product, which includes a computer program that, when executed by a processor, implements the above-described method.

[0155] Those skilled in the art will understand that embodiments of this specification can be provided as methods, systems, or computer program products. Therefore, this specification may take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this specification may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0156] This specification is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this specification. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create a machine for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0157] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0158] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0159] The above specific embodiments further illustrate the purpose, technical solutions, and beneficial effects of this specification. It should be understood that the above are merely specific embodiments of this specification and are not intended to limit the scope of protection of this specification. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this specification should be included within the scope of protection of this specification.

Claims

1. A method for determining reservoir parameters, characterized in that, include: Based on well logging data and seismic data, the anisotropy parameters of the orthogonal medium, the low-frequency initial model, and the mixed phase wavelet are determined. Specifically, this includes determining the fracture orientation based on the well logging data; determining the target seismic data corresponding to the fracture orientation from the seismic data; and determining the mixed phase wavelet based on the target seismic data. The target P-wave reflection formula is obtained by combining and updating the preset orthogonal medium P-wave reflection formula. Specifically, this includes: simplifying the preset orthogonal medium crack disturbance reflection coefficient formula in the preset orthogonal medium P-wave reflection formula to obtain the target orthogonal medium crack disturbance reflection coefficient formula; and determining the target P-wave reflection formula based on the target orthogonal medium crack disturbance reflection coefficient formula and the preset transverse isotropic P-wave reflection coefficient formula in the preset orthogonal medium P-wave reflection formula. Based on the orthogonal medium anisotropy parameters, the low-frequency initial model, and the mixed phase wavelet, a minimum objective function is constructed; and Based on the minimum objective function and the seismic data, the target P-wave reflection formula is solved to obtain the target reservoir parameters. These parameters include acoustic impedance, anisotropic shear modulus, P-wave phase velocity along the fracture strike direction, azimuth anisotropy gradient, and relative fracture density. The process of solving the target P-wave reflection formula based on the minimum objective function and the seismic data to obtain the target reservoir parameters includes: solving the target P-wave reflection formula based on the minimum objective function to obtain the acoustic impedance, the anisotropic shear modulus, and the P-wave phase velocity along the fracture strike direction; determining the seismic amplitude difference between the first residual sub-seismic data (excluding the fracture strike direction) and the second residual sub-seismic data (parallel to the fracture strike direction) in the seismic data; and determining the azimuth anisotropy gradient and the relative fracture density based on the minimum objective function and the seismic amplitude difference.

2. The method according to claim 1, characterized in that, The formula for the reflection coefficient of the target orthogonal medium crack disturbance includes: Among them, the θ Characterizing the angle of incidence, the The azimuth angle relative to the crack normal plane, the The The The The parameters characterizing the anisotropy of longitudinal waves, the The second derivative characterizing the phase velocity function of the longitudinal wave at perpendicular incidence, the The squared term characterizing the ratio of transverse to longitudinal wave velocities, and the aforementioned Characterizing parameters of transverse wave anisotropy.

3. The method according to claim 1, characterized in that, The target longitudinal wave reflection formula includes: Among them, the The formula characterizing the preset transversely isotropic longitudinal wave reflection coefficient, the The formula characterizing the reflection coefficient of the crack disturbance in the target orthogonal medium is as follows: θ Characterizing the angle of incidence, the The azimuth angle relative to the crack normal plane, the The The The ρ Characterizing density, the The parameters characterizing the anisotropy of longitudinal waves, the The second derivative characterizing the phase velocity function of the longitudinal wave at perpendicular incidence, the The squared term characterizing the ratio of transverse to longitudinal wave velocities, the The parameters characterizing transverse wave anisotropy, the Characterizing the longitudinal wave velocity, and the aforementioned The square term representing the ratio of transverse to longitudinal wave velocities to four times.

4. The method according to claim 1, characterized in that, The minimum objective function includes: Among them, the Characterizing seismic data, the G Characterizing the linear forward modeling operator determined based on the hybrid phase wavelet, the Characterizes the prior information of the model parameter vector determined based on the low-frequency initial model, and the Characterize the parameters of the target reservoir.

5. A reservoir parameter determination device, characterized in that, include: The first determining unit is used to determine the orthogonal medium anisotropy parameters, low-frequency initial model, and mixed phase wavelet based on well logging data and seismic data. Specifically, it includes determining the fracture orientation based on the well logging data; determining the target seismic data corresponding to the fracture orientation from the seismic data; and determining the mixed phase wavelet based on the target seismic data. The updating unit is used to perform a combined update on the preset orthogonal medium longitudinal wave reflection formula to obtain the target longitudinal wave reflection formula. Specifically, it includes: simplifying the preset orthogonal medium crack disturbance reflection coefficient formula in the preset orthogonal medium longitudinal wave reflection formula to obtain the target orthogonal medium crack disturbance reflection coefficient formula; and determining the target longitudinal wave reflection formula based on the target orthogonal medium crack disturbance reflection coefficient formula and the preset transverse isotropic longitudinal wave reflection coefficient formula in the preset orthogonal medium longitudinal wave reflection formula. The construction unit is used to construct a minimum objective function based on the orthogonal medium anisotropy parameters, the low-frequency initial model, and the mixed phase wavelet; and The solution unit is used to solve the target P-wave reflection formula based on the minimum objective function and the seismic data to obtain target reservoir parameters. The target reservoir parameters include acoustic impedance, anisotropic shear modulus, P-wave phase velocity along the fracture strike direction, azimuth anisotropy gradient, and relative fracture density. The process of solving the target P-wave reflection formula based on the minimum objective function and the seismic data to obtain the target reservoir parameters includes: solving the target P-wave reflection formula based on the minimum objective function to obtain the acoustic impedance, the anisotropic shear modulus, and the P-wave phase velocity along the fracture strike direction; determining the seismic amplitude difference between the first residual sub-seismic data (excluding the fracture strike direction) and the second residual sub-seismic data (parallel to the fracture strike direction) in the seismic data; and determining the azimuth anisotropy gradient and the relative fracture density based on the minimum objective function and the seismic amplitude difference.

6. A computer device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the method of any one of claims 1-4.

7. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program that, when executed by a processor, performs the method of any one of claims 1-4.

Images