Diffracted wave imaging method and device for underground discontinuous geologic body

Abstract

The embodiment of the invention provides a diffracted wave imaging method and device for an underground discontinuous geologic body, electronic equipment, a storage medium and a program product. The method comprises the following steps: carrying out migration on a seismic data set by utilizing a migration velocity field to obtain an angle domain imaging gather; by means of the angle domain imaging gather and a preset illumination angle calculation rule, the illumination angle at the travel time curve endpoint matched with each offset position is obtained through calculation; performing hyperbolic pulling positive and negative transformation on the offset angle gathers matched with the same offset positions by using the illumination angles at the end points of the travel time curve matched with each offset position to obtain diffracted wave signals corresponding to each offset position; and in response to an angle domain diffracted wave imaging gather constructed according to the diffracted wave signal corresponding to each shifted position, superposing the angle domain diffracted wave imaging gather by using the observation dip angle to obtain a diffracted wave image. By using the method of the embodiment of the invention, angle domain diffracted wave imaging can be realized.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the technical field of seismic data processing, and in particular to a method and device for imaging diffraction waves of underground discontinuous geological bodies, an electronic device, a computer readable storage medium, and a computer program product. BACKGROUND

[0002] According to the Huygens principle, when the underground geological body acts as a seismic source to excite seismic waves to the ground surface, continuous geological reflectors form a plane wave front, and discontinuous geological diffraction bodies (such as fault points, collapse columns, and stratigraphic pinch points) form a spherical wave spread. These discontinuous geological bodies are closely related to oil and gas migration and coal mining safety, and accurate identification of them helps to improve oil and gas extraction efficiency, reduce extraction costs, and reduce geological risks in coal mining. The geological discontinuous information is mainly manifested as the characteristics of diffraction waves in the seismic wave field, so diffraction wave imaging is a key technology for obtaining such information. However, the diffraction wave energy is usually weak and is easily disturbed by strong reflected waves, so the core challenge of diffraction wave imaging is how to effectively extract the weak diffraction wave signal in the strong reflection background.

[0003] At present, the angle domain imaging methods of the prior art mainly fall into two categories: one class identifies the stable phase point position of the reflected wave in the angle domain, and then cuts off the reflected energy in this region to highlight the diffraction wave; the other class uses the horizontal linear distribution characteristics of the diffraction wave in the angle domain to extract the diffraction wave energy by using mean filtering or median filtering methods. However, the first method often loses part of the diffraction wave energy when cutting off the reflected energy near the stable phase point, which is not conducive to high-quality diffraction wave imaging. The second method is prone to residual reflected wave energy in the extraction process due to the weak energy of the diffraction wave itself and the limited range of actual observation angles, which in turn leads to artifacts in the diffraction wave migration imaging. SUMMARY

[0004] To solve the above technical problems, the scheme of the present disclosure is proposed. Embodiments of the present disclosure provide a method, device, electronic device, computer readable storage medium, and computer program product for imaging diffraction waves of underground discontinuous geological bodies.

[0005] According to a first aspect of an embodiment of the present disclosure, a method for imaging diffraction waves of underground discontinuous geological bodies is provided, wherein the method comprises:

[0006] In response to obtaining a seismic data set associated with a target region underground and a migration velocity field, the seismic data set is migrated using the migration velocity field to obtain an angle domain imaging gather; wherein the target region underground includes a discontinuous geological body, the migration velocity field includes a plurality of migration velocities, each migration velocity is associated with a parameter including a migrated position and a migrated time, and the angle domain imaging gather is associated with a parameter including the migrated position, the migrated time and an observation dip angle, and the same migrated position and migrated time correspond to a plurality of different observation dip angles;

[0007] Using the angle domain imaging gather and a preset illumination angle calculation rule, an illumination angle at an end point of a travel time curve matching each migration position is calculated; wherein the travel time curve is a travel time curve of a phase axis of a mixed wave in the angle domain imaging gather, and the mixed wave includes a reflected wave and a diffracted wave;

[0008] For a migration angle gather matching each migrated position of the angle domain imaging gather, hyperbolic pull positive and negative transformation is performed on the migration angle gather matching the same migrated position using the illumination angle at the end point of the travel time curve matching each migrated position to obtain a diffracted wave signal corresponding to each migrated position; wherein the diffracted wave signal is associated with a parameter including the migrated time and the observation dip angle;

[0009] In response to constructing an angle domain diffracted wave imaging gather according to the diffracted wave signal corresponding to each migrated position, the angle domain diffracted wave imaging gather is stacked using the observation dip angle to obtain diffracted wave imaging.

[0010] According to a second aspect of the embodiments of the present disclosure, a device for diffracted wave imaging of a discontinuous geological body underground is provided, wherein the device includes:

[0011] A data migration unit is configured to, in response to obtaining a seismic data set associated with a target region underground and a migration velocity field, migrate the seismic data set using the migration velocity field to obtain an angle domain imaging gather; wherein the target region underground includes a discontinuous geological body, the migration velocity field includes a plurality of migration velocities, each migration velocity is associated with a parameter including a migrated position and a migrated time, and the angle domain imaging gather is associated with a parameter including the migrated position, the migrated time and an observation dip angle, and the same migrated position and migrated time correspond to a plurality of different observation dip angles;

[0012] An illumination angle calculation unit is configured to calculate an illumination angle at an end point of a travel time curve matching each migration position using the angle domain imaging gather and a preset illumination angle calculation rule; wherein the travel time curve is a travel time curve of a phase axis of a mixed wave in the angle domain imaging gather, and the mixed wave includes a reflected wave and a diffracted wave.

[0013] The pull-transform unit is configured to: match the offset angle gather for each offset position of the angle domain imaging gather, and perform hyperbolic pull-forward and inverse transformation on the offset angle gathers that match the same offset position using the illumination angle at the endpoint of the travel time curve of each offset position, to obtain the diffraction wave signal corresponding to each offset position; wherein, the diffraction wave signal correlation parameters include the offset time and the observation tilt angle;

[0014] The diffraction wave imaging unit is configured to: in response to construct an angle-domain diffraction wave imaging gather based on the diffraction wave signal corresponding to each of the offset positions, superimpose the angle-domain diffraction wave imaging gather using the observation tilt angle to obtain a diffraction wave image.

[0015] According to a third aspect of the present disclosure, an electronic device is provided, the electronic device comprising: a processor; a memory for storing executable instructions of the processor; the processor being configured to read the executable instructions from the memory and execute the instructions to implement the method of the present disclosure for diffraction imaging of underground discontinuous geological bodies.

[0016] According to a fourth aspect of the present disclosure, a computer-readable storage medium is provided, the storage medium storing a computer program for executing the method for diffraction imaging of underground discontinuous geological bodies as described in the present disclosure.

[0017] According to a fifth aspect of the present disclosure, a computer program product is provided, including a computer program, wherein when executed by a processor, the computer program implements the method for diffraction imaging of underground discontinuous geological bodies as described in the present disclosure.

[0018] As described above, the method for diffraction wave imaging of discontinuous underground geological bodies provided in this disclosure can first increase the difference in the characteristic curves of the phase axes of reflected and diffracted waves by increasing the migration velocity, and then achieve angular domain diffraction wave imaging by using hyperbolic pull transform. The method described in this disclosure does not require the removal of energy near the stable phase point, and can directly utilize the curve regularity of strong reflection phase axes, resulting in less damage to diffracted waves. Furthermore, since strong reflection phase axes are easier to identify than weak diffracted phase axes, reflected and diffracted waves can be separated more effectively, which to some extent facilitates the subsequent application of diffraction wave imaging for the detection of underground geological structures. Attached Figure Description

[0019] The above and other objects, features and advantages of the present disclosure will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings. The drawings provided below are for illustrative purposes and are included to further convey the principles of the present disclosure and are not intended to limit the scope of the present disclosure. The same reference numbers in different drawings represent the same components or steps.

[0020] Figure 1 is a flowchart of a method for imaging a discontinuous subsurface geological body by diffracted waves according to an example embodiment of the present disclosure;

[0021] Figure 2 is a schematic diagram of a time curve of a reflection angle domain imaging gather according to an example embodiment of the present disclosure;

[0022] Figure 3 is a schematic diagram of a time curve of a diffraction angle domain imaging gather according to an example embodiment of the present disclosure;

[0023] Figure 4 is a schematic diagram of a time curve of a diffraction angle domain imaging gather according to an example embodiment of the present disclosure; Figure 1 is a schematic diagram of a time curve of a diffraction angle domain imaging gather according to an example embodiment of the present disclosure;

[0024] Figure 5 is a schematic diagram of a time curve of a diffraction angle domain imaging gather according to an example embodiment of the present disclosure; Figure 1 is a schematic diagram of a time curve of a diffraction angle domain imaging gather according to an example embodiment of the present disclosure;

[0025] Figure 6 is a schematic diagram of a time curve of a diffraction angle domain imaging gather according to an example embodiment of the present disclosure; Figure 1 is a schematic diagram of a time curve of a diffraction angle domain imaging gather according to an example embodiment of the present disclosure;

[0026] Figure 7 is a schematic diagram of a time curve of a diffraction angle domain imaging gather according to an example embodiment of the present disclosure; Figure 1 is a schematic diagram of a time curve of a diffraction angle domain imaging gather according to an example embodiment of the present disclosure;

[0027] Figure 8 is a schematic diagram of a time curve of a diffraction angle domain imaging gather according to an example embodiment of the present disclosure; Figure 1 is a schematic diagram of a time curve of a diffraction angle domain imaging gather according to an example embodiment of the present disclosure;

[0028] Figure 9 is a schematic diagram of a device for imaging a discontinuous subsurface geological body by diffracted waves according to an example embodiment of the present disclosure;

[0029] Figure 10 is a schematic diagram of an electronic device according to an example embodiment of the present disclosure. DETAILED DESCRIPTION

[0030] The present disclosure will be further described below with reference to the embodiments shown in the drawings. Obviously, the described embodiments are only a part of the embodiments of the present disclosure, and are not all the embodiments of the present disclosure. It should be understood that the present disclosure is not limited to the example embodiments described herein.

[0031] It should be noted that, unless otherwise specified, the relative arrangement, numerical expressions and values of the components and steps set forth in these embodiments do not limit the scope of the present disclosure.

[0032] Those skilled in the art can understand that the terms "first", "second" and the like in the embodiments of the present disclosure are only used to distinguish different steps, devices or modules, and do not represent any specific technical meaning, nor indicate their logical order.

[0033] It should also be understood that in the embodiments of the present disclosure, "a plurality of" can mean two or more, and "at least one" can mean one, two or more.

[0034] It should also be understood that for any component, data or structure mentioned in the embodiments of the present disclosure, unless specifically limited or the context gives the opposite indication, it can be understood as one or more in general.

[0035] In addition, the term "and / or" in the present disclosure is only a description of the association relationship between the associated objects, which means that there can be three relationships, for example, A and / or B can represent the existence of A alone, the existence of A and B at the same time, and the existence of B alone. In addition, the character " / " in the present disclosure generally represents an "or" relationship between the associated objects.

[0036] It should also be understood that the description of the embodiments of the present disclosure focuses on the differences between the embodiments, and the same or similar parts can be referred to each other, and will not be repeated here for the sake of brevity.

[0037] At the same time, it should be understood that, for the sake of brevity, the size of each part shown in the drawings is not drawn in accordance with the actual proportional relationship.

[0038] The following description of at least one example embodiment is merely illustrative in nature and does not in any way limit the disclosure and its application or uses.

[0039] Techniques, methods and devices known to those of ordinary skill in the relevant art can not be discussed in detail, but should be considered as part of the specification when appropriate.

[0040] It should be noted that like reference numerals and letters refer to like items throughout the several views, and each new view described herein can not necessarily require further discussion of elements already described.

[0041] Embodiment 1

[0042] Figure 1 is a flowchart of a method for imaging a discontinuous subsurface geological body with diffracted waves according to an example embodiment of the present disclosure. The method can be executed on a server, which can include but is not limited to a server, a cloud computing platform.

[0043] Specifically, referring to Figure 1 , the method for imaging a discontinuous subsurface geological body with diffracted waves comprises:

[0044] S110, in response to obtaining a seismic dataset associated with a subsurface target region and a migration velocity field, migrating the seismic dataset using the migration velocity field to obtain an angle domain imaging gather.

[0045] wherein the subsurface target region comprises a discontinuous geological body.

[0046] wherein the migration velocity field comprises a plurality of migration velocities, each migration velocity being associated with parameters including a post-migration position and a post-migration time. Specifically, the migration velocity field corresponding to a post-migration position x m may be expressed as V(x m , t m ); wherein x m represents the spatial position of post-migration data (i.e., post-migration position), t m represents the time of post-migration data (i.e., post-migration time).

[0047] wherein the angle domain imaging gather is associated with parameters including the post-migration position, the post-migration time and an observation dip angle, and a same post-migration position and post-migration time corresponds to a plurality of different observation dip angles.

[0048] S120, using the angle domain imaging gather and a preset illumination angle calculation rule, calculating an illumination angle at an end point of a traveltime curve matching each post-migration position.

[0049] wherein the traveltime curve is a traveltime curve of a moveout event of the angle domain imaging gather, and the moveout event comprises a reflected wave and a diffracted wave.

[0050] S130, match the offset angle gather of each of the post-offset positions with respect to the angle domain imaging gathers, perform hyperbolic pull-sum forward and inverse transformation on the offset angle gathers matching the same post-offset position with respect to the illumination angle at the end points of the travel time curve matching each of the post-offset positions, to obtain the diffraction wave signal corresponding to each of the post-offset positions.

[0051] Wherein, the diffraction wave signal correlation parameter comprises the post-offset time and the observation dip angle.

[0052] S140, in response to constructing the angle domain diffraction wave imaging gathers according to the diffraction wave signals corresponding to each of the post-offset positions, stack the angle domain diffraction wave imaging gathers with respect to the observation dip angle, to obtain diffraction wave imaging.

[0053] Optionally, the "seismic data set, offset velocity field" can be stored in a corresponding data server. As a server executing the subject of step S110, it can be communicated with the data server to obtain the "seismic data set, offset velocity field".

[0054] The seismic data set comprises a plurality of seismic data, and each of the seismic data correlation parameters comprises a pre-offset position and a pre-offset time. Specifically, the seismic data can be represented as U(x, t), for example; wherein x represents the spatial position of the pre-offset data (i.e., the pre-offset position), and t represents the time of the pre-offset data (i.e., the pre-offset time).

[0055] The specific content of the "preset illumination angle calculation rule" will be described in the following embodiments, which will not be described here. Wherein, the illumination angle at the end points of the travel time curve can be used as the "observation dip angle reference of pull-sum transformation calculation", and the specific implementation details are described below.

[0056] It should be noted that the principle of separating the diffraction wave signal by using "hyperbolic pull-sum transformation" can be summarized as follows:

[0057] The diffraction wave and the reflection have different distribution characteristics in the angle domain common imaging point gather, and when the offset velocity changes, the characteristics of the two are not consistent.

[0058] Specifically, the travel time curve t r can be represented as:

[0059]

[0060] Wherein, θ represents the stratum dip angle; α represents the observation dip angle; t0 is the corresponding vertical two-way time at the reflection point or the diffraction point; γ can be regarded as representing the velocity error, i.e., the ratio of the velocity used for offset imaging to the accurate velocity.

[0061] Diffracted wave in angle domain imaging gather's event traveltime curve t d Can be expressed as:

[0062]

[0063] Wherein, t0(x m ) is t0.

[0064] Corresponding to different γ values, diffracted wave and reflected wave have different performance characteristics, specifically, referring to Figure 1 , in the case of γ value greater than 1, γ value equal to 1 and γ value less than 1, the reflected wave traveltime curve is open upward. Referring to Figure 2 , in the case of γ value greater than 1, that is, the migration velocity is greater than the true velocity, the diffracted wave traveltime curve is open downward; in the case of γ value equal to 1, that is, the migration velocity is equal to the true velocity, the diffracted wave traveltime curve is a horizontal line; in the case of γ value less than 1, that is, the migration velocity is less than the true velocity, the diffracted wave traveltime curve is open upward.

[0065] Based on the above analysis and referring to Figure 2 , Figure 3 , we need to use the characteristics that in the case of γ value greater than 1, the diffracted wave traveltime curve is open downward, and the reflected wave traveltime curve is open upward (i.e. the curve opening of the two is different) to separate the two. Based on this, in the above steps, the migration velocity field is amplified by using it as an amplification coefficient (i.e. a value of γ value greater than 1, for example, γ = 1.1); then, after steps S110, S120, S130 is executed, that is, using hyperbolic pull positive and negative transformation, the reflected wave (i.e. the part open upward) in the event traveltime curve of the migration angle gather is filtered out, so that only the diffracted wave is retained.

[0066] As described above, using the method for diffracted wave imaging of underground discontinuous geological body provided by the embodiments of the present disclosure, first, the difference between the reflected wave and the diffracted wave event curve characteristics can be increased by increasing the migration velocity, then the hyperbolic pull transformation can be used to realize the angle domain diffracted wave imaging. The method described in the embodiments of the present disclosure does not need to cut off the energy near the stable phase point, and can directly use the curve rule of strong reflection event to damage the diffracted wave less; and since the strong reflection event is more easily identified than the weak diffracted event, the reflected wave and the diffracted wave can be more effectively separated, and then to a certain extent, it is conducive to the implementation of the subsequent application link based on the diffracted wave imaging to detect the underground geological structure.

[0067] Embodiment 2

[0068] Based on the above embodiment, referring to Figure 4 , the "using the migration velocity field to migrate the seismic data set to obtain an angle domain imaging gather" in step S110 can include:

[0069] S1110, multiplying the preset amplification coefficient with the migration velocity field to obtain a new migration velocity field; wherein the preset amplification coefficient is greater than 1.

[0070] Wherein, referring to the curve characteristics of the reflected wave and the diffraction wave shown in Figure 2 , Figure 3 , it can be seen that when the migration velocity greater than the true velocity is used for migration, the reflected wave curve opens upward, and the diffraction wave curve opens downward, which has obvious difference.

[0071] The original migration velocity field V(x m ,t m ) (i.e., the migration velocity field) has little difference with the true velocity, which is assumed as the accurate velocity in the embodiment. In order to ensure that the migration velocity is greater than the accurate velocity, the read migration velocity field needs to be increased. Specifically, the amplification can be performed through the following calculation formula:

[0072]

[0073] Wherein, the preset amplification coefficient C may take values including but not limited to 1.1, so as to obtain the new migration velocity field (i.e., the enhanced velocity field) V c (x m ,t m ), which can also be written as v c (x m ,t m ) in the following; of course, when the preset amplification coefficient C is 1.1, it corresponds to the value when the γ value in Figure 3 is greater than 1.

[0074] S1120, constructing a Kirchhoff integral kernel by using the pre-migration position, the pre-migration time, the new migration velocity field, the post-migration position and the post-migration time.

[0075] Wherein, the Kirchhoff integral kernel includes a travel time constraint kernel and an angle constraint kernel.

[0076] Optionally, the step S1120 can be realized by the following way:

[0077] Step I1, constructing a travel time constraint kernel by using the pre-migration position, the pre-migration time, the new migration velocity field, the post-migration position and the post-migration time based on the Dirac function.

[0078] In a specific example, the travel time constraint kernel can be represented by the following calculation formula.

[0079]

[0080] wherein δ(·) denotes a Dirac delta function; x m denotes a post-migration position; t m denotes a post-migration time; v c (x m , t m ) denotes a new migration velocity field; x denotes a pre-migration position; t denotes a pre-migration time.

[0081] Step I2, constructing an angle constraint kernel based on the Dirac function, the pre-migration position, the new migration velocity field, the post-migration position, and the post-migration time.

[0082] In a specific example, the angle constraint kernel can be represented by the following calculation formula.

[0083]

[0084] Δx = x - x m

[0085] wherein δ(·) denotes a Dirac delta function; x m denotes a post-migration position; t m denotes a post-migration time; v c (x m , t m ) denotes a new migration velocity field corresponding to the post-migration position x m ; x denotes a pre-migration position; a denotes an observation dip angle.

[0086] Step I3, multiplying the travel time constraint kernel and the angle constraint kernel to obtain the Kirchhoff integral kernel.

[0087] In a specific example, the Kirchhoff integral kernel can be represented by the following calculation formula.

[0088]

[0089] wherein δ(·) denotes a Dirac delta function; x m denotes a post-migration position; t m denotes a post-migration time; v c (x m , t m ) denotes a new migration velocity field corresponding to the post-migration position x m ; x denotes a pre-migration position; t denotes a pre-migration time; a denotes an observation dip angle.

[0090] S1130, performing double integration with respect to the pre-migration time and the pre-migration position by taking the product of the seismic data set and the Kirchhoff integral kernel as an integrated item to obtain the angle domain imaging gather.

[0091] Optionally, the angle domain imaging gathers can be calculated by using the following calculation formula.

[0092]

[0093] wherein I(x m , t m , a) represents the angle domain imaging gathers corresponding to the post-migrated position x m ; and U(x, t) represents the seismic data set.

[0094] Embodiment 3

[0095] In the above embodiments, with reference to Figure 5 , the step S120 “calculating the illumination angle at the end point of the travel time curve matching each post-migrated position by using the angle domain imaging gathers and a preset illumination angle calculation rule” can comprise:

[0096] S1210, stacking the angle domain imaging gathers by using the observation dip angle to obtain a first post-migration imaging profile.

[0097] Since the angle domain imaging gather associated parameters include the post-migrated position, post-migrated time and observation dip angle, and the same post-migrated position and post-migrated time correspond to multiple different observation dip angles, optionally, the step S1210 can be represented by using the following calculation formula.

[0098]

[0099] wherein S(x m , t m ) represents the first post-migration imaging profile corresponding to the post-migrated position x m ; a represents the observation dip angle; and I(x m , t m , a) represents the angle domain imaging gathers corresponding to the post-migrated position x m .

[0100] S1220, calculating the local dip angle matching each post-migrated position by using the plane wave destruction method based on the first post-migration imaging profile.

[0101] The plane wave destruction (PWD) is a seismic data dip angle estimation method based on the local plane wave model, and the core idea is that the local wave field is approximately equal to the plane wave propagating along a specific direction. The mathematical expression is as follows:

[0102]

[0103] wherein U, i.e. U(x, t), represents the seismic data set; and p represents the local dip angle.

[0104] Based on this, step S1220 can be implemented by the following method.

[0105] 1) Construct a prediction filter as shown in the following formula for each sampling point (x m , t m );

[0106]

[0107] Wherein, A represents the prediction filter matrix, p represents the local dip angle to be solved; S(x m , t m ) represents the first offset imaging profile corresponding to the offset position x m ; Δt represents the time step, i.e. the sampling interval.

[0108] 2) Solve the optimal p by the least square method as follows.

[0109]

[0110] Wherein, S obs represents the matrix on the left side of the equation of formula (1); S pred represents the matrix on the right side of the equation of formula (1).

[0111] The solution of formula (2) can include but not limited to iterative optimization (such as gradient descent method); by solving formula (2), the local dip angle matching each offset position can be obtained.

[0112] S1230, calculate the product of the local dip angle matching each offset position and the corresponding new offset velocity, and divide by two to obtain the illumination angle at the end point of the travel time curve matching each offset position.

[0113] Optionally, taking the offset position x m as an example, the illumination angle at the end point of the travel time curve matching x m can be calculated by the following calculation formula.

[0114]

[0115] Wherein, a0(x m , t m ) represents the illumination angle at the end point of the travel time curve corresponding to the offset position x m ; p(x m , t m ) represents the local dip angle corresponding to the offset position x m ; v c (x m , t m ) represents the new offset velocity corresponding to the offset position x ma new migration velocity field.

[0116] Embodiment 4

[0117] On the basis of the above embodiments, referring to Figure 6 , the step S130 "matching, for each of the post-migration positions, the migration angle gathers with the illumination angle at the end point of the traveltime curve of each of the post-migration positions, performing hyperbolic pullback forward transform on the migration angle gathers matching the same post-migration position to obtain the diffraction wave signal corresponding to each of the post-migration positions" can include:

[0118] S1310, for each of the post-migration positions, stacking the migration angle gathers matching the post-migration position using the observation dip angle to obtain a second migration imaging profile.

[0119] For ease of understanding, in a specific example, taking the first post-migration position x1 as an example, the migration angle gathers matching x1 can be expressed in the following form.

[0120] I1(t m , α) = I(x m = x1, t m , α)

[0121] The second migration imaging profile matching x1 can be expressed as:

[0122]

[0123] It should be noted that the migration angle gathers and the second migration imaging profile corresponding to other post-migration positions can be adaptively determined with reference to the above form.

[0124] S1320, for each of the post-migration positions, performing hyperbolic pullback forward transform on the second migration imaging profile matching the post-migration position based on the illumination angle at the end point of the traveltime curve of the post-migration position to obtain a pullback domain.

[0125] The pullback domain associated parameters include hyperbolic vertex time T and curvature parameter q.

[0126] In an optional example, taking the first post-migration position x1 as an example; the hyperbolic pullback forward transform can be performed using the following calculation formula.

[0127]

[0128] Wherein, m1(τ, q) represents the pullback domain; in this example, α0 corresponds to the illumination angle at the end point of the traveltime curve of the post-migration position x1; T represents the hyperbolic vertex time; and q represents the curvature parameter.

[0129] S1330, filter out the part of the pullback domain corresponding to the curvature parameter less than zero, to obtain a positive pullback domain.

[0130] It should be noted that the reflection wave curve opens upward (q < 0), and the diffraction wave curve opens downward (q > 0). Therefore, based on the S1320 example, the part of the pullback domain m1(τ, q) with q < 0 is deleted in the S1330 example, that is, a positive pullback domain is obtained.

[0131] S1340, for each of the offset positions, based on the illumination angle at the end point of the travel time curve matching the offset position, perform a hyperbolic pullback inverse transform on the positive pullback domain to obtain a primary diffraction wave signal corresponding to each of the offset positions.

[0132] In an optional example, taking the first offset position x1 as an example; the hyperbolic pullback inverse transform can be performed on the pullback domain m1(τ, q) obtained by formula (3) according to the following calculation formula.

[0133]

[0134] wherein D1(t m ,α) represents the primary diffraction wave signal corresponding to the offset position x1.

[0135] S1350, using the first curve, correcting the primary diffraction wave signal of each of the offset positions to obtain a diffraction wave signal corresponding to each of the offset positions.

[0136] wherein the first curve is the travel time curve of the diffraction wave in the angle domain imaging gather.

[0137] Here, the first curve, that is, the travel time curve t d of the diffraction wave in the angle domain imaging gather, can be represented by the following calculation formula.

[0138]

[0139] Optionally, referring to Figure 7 , step S1350 can be implemented in the following way.

[0140] S13510, using a function representing the first curve, calculating a diffraction wave offset time correction amount of the primary diffraction wave signal corresponding to each of the offset positions.

[0141] In a specific example, taking the offset position x1 as an example, the diffraction wave offset time correction amount of the primary diffraction wave signal corresponding to x1 can be obtained based on formula (4) by using the following steps.

[0142] A1, starting from formula (4), substituting γ = c to obtain:

[0143]

[0144] The travel time at the real velocity (c=1) is:

[0145] t 真实 =t0cosα

[0146] The travel time error is:

[0147]

[0148] where t0 represents the real vertical two-way travel time.

[0149] A2, based on the vertical time equivalence principle, the offset time corresponding to the offset position x m is t m (that is, the observed vertical time after offset) and t0 are equivalent, so in this example, t m can be used to replace t0; thus, we get:

[0150]

[0151] A3, the calculation formula in A2 can be expanded and transformed to obtain the following form of calculation formula.

[0152]

[0153] In the above example, first, the steps A1-A3 can be used to determine the diffraction wave offset time correction amount calculation formula corresponding to each of the offset positions, and then in the specific application stage, by matching each of the offset positions, the diffraction wave offset time correction amount corresponding to any point in the primary diffraction wave signal can be calculated by using the calculation formula (5).

[0154] S13520, using the diffraction wave offset time correction amount, the offset time associated with the matched primary diffraction wave signal is corrected to obtain the diffraction wave signal corresponding to each of the offset positions.

[0155] In a specific example, taking the offset position x1 as an example, the offset time associated with the matched primary diffraction wave signal can be corrected by using the following calculation formula.

[0156] E1(t D ,α)=D1(t m -Δt d ,α)

[0157] where E1(t m ,α) represents the diffraction wave signal corresponding to the offset position x1; D1(t m ,α) represents the primary diffraction wave signal corresponding to the offset position x1.

[0158] Embodiment 5

[0159] On the basis of the above embodiments, referring to Figure 8 , the “constructing an angle domain diffraction wave imaging gather according to each of the post-offset positions corresponding diffraction wave signals” in step S140 can include:

[0160] S1410, determining a time sequence according to the post-offset time sequence of each of the post-offset positions corresponding diffraction wave signals.

[0161] S1420, sorting the diffraction wave signals corresponding to each of the post-offset positions according to the time sequence, to obtain a diffraction wave signal sequence based on the time dimension;

[0162] S1430, integrating the diffraction wave signal sequence into a data set to obtain the angle domain diffraction wave imaging gather.

[0163] The correlation parameters of the angle domain diffraction wave imaging gather include post-offset positions, post-offset times and observation dips, and the same post-offset position and post-offset time correspond to multiple different observation dips.

[0164] The angle domain diffraction wave imaging gather can be represented as E(x m ,t D ,α) for example.

[0165] Optionally, the “stacking the angle domain diffraction wave imaging gather according to the observation dip to obtain diffraction wave imaging” in step S140 can include:

[0166] The angle domain diffraction wave imaging gathers matching different observation dips are added to obtain diffraction wave imaging.

[0167] Optionally, the addition is to stack the angle domain diffraction wave imaging gathers matching different observation dips along the observation dip.

[0168] In a specific example, the stacking can be expressed as

[0169] As described above, by using the method for imaging diffracted waves of a discontinuous subsurface geological body provided by the embodiments of the present disclosure, first, the difference between the reflection wave and the diffracted wave can be increased by improving the migration velocity, and then the angle domain diffracted wave imaging can be realized by using the hyperbolic pull transformation. The method described in the embodiments of the present disclosure can directly use the curve rule of the strong reflection event without cutting off the energy near the stable phase point, and the damage to the diffracted wave is small; and since the strong reflection event is more easily identified than the weak diffracted event, the reflection wave and the diffracted wave can be more effectively separated, and then to a certain extent, it is conducive to the subsequent implementation of detecting the subsurface geological structure based on the diffracted wave imaging.

[0170] Embodiment 6

[0171] It should be understood that the foregoing embodiments herein regarding the method for imaging diffracted waves of a discontinuous subsurface geological body can also be similarly applied to the following device for imaging diffracted waves of a discontinuous subsurface geological body for similar expansion. For the sake of simplicity, it is not described in detail.

[0172] Figure 9 is a device structure schematic diagram provided by an exemplary embodiment of the present disclosure for imaging diffracted waves of a discontinuous subsurface geological body. Referring to Figure 9 , the device comprises:

[0173] The data migration unit 910 is configured to, in response to obtaining a seismic data set associated with a subsurface target region and a migration velocity field, migrate the seismic data set by using the migration velocity field to obtain an angle domain imaging gather; wherein the subsurface target region comprises a discontinuous geological body, the migration velocity field comprises a plurality of migration velocities, each migration velocity is associated with parameters including a migrated position and a migrated time, and the angle domain imaging gather is associated with parameters including the migrated position, the migrated time and an observation dip angle, and the same migrated position and migrated time correspond to a plurality of different observation dip angles;

[0174] The illumination angle calculation unit 920 is configured to calculate the illumination angle at the end point of the travel time curve matching each migration position by using the angle domain imaging gather and a preset illumination angle calculation rule; wherein the travel time curve is the travel time curve of the event of the mixed wave on the angle domain imaging gather, and the mixed wave includes reflection wave and diffracted wave;

[0175] The pulling transformation unit 930 is configured to: for the offset angle gathers matched with each of the offset positions, perform a hyperbolic pulling forward and reverse transformation on the offset angle gathers matched with the same offset position by using the illumination angle at the travel time curve end point matched with each of the offset positions, to obtain a diffraction wave signal corresponding to each of the offset positions; wherein the diffraction wave signal associated parameters include the offset time and the observation dip angle.

[0176] The diffraction wave imaging unit 940 is configured to: in response to constructing an angle domain diffraction wave imaging gather according to the diffraction wave signal corresponding to each of the offset positions, perform stacking on the angle domain diffraction wave imaging gather by using the observation dip angle, to obtain diffraction wave imaging.

[0177] As described above, by using the device for diffraction wave imaging of underground discontinuous geological bodies provided by the embodiments of the present disclosure, first, the difference between the reflection wave and the diffraction wave can be increased by improving the offset velocity, and then the hyperbolic pulling transformation can be used to realize the angle domain diffraction wave imaging. The device described in the embodiments of the present disclosure can directly use the curve rule of the strong reflection event without cutting off the energy near the stable phase point, and the damage to the diffraction wave is small; and since the strong reflection event is more easily identified than the weak diffraction event, the reflection wave and the diffraction wave can be more effectively separated, and thus the subsequent application step of detecting the underground geological structure based on the diffraction wave imaging can be facilitated to a certain extent.

[0178] Embodiment 7

[0179] In addition, the embodiments of the present disclosure also provide an electronic device, including: a memory, configured to store a computer program; a processor, configured to execute the computer program stored in the memory, and when the computer program is executed, the method for diffraction wave imaging of underground discontinuous geological bodies described in any one of the embodiments of the present disclosure is implemented.

[0180] Figure 10 is a structural schematic diagram of an application embodiment of the electronic device of the present disclosure. Next, the electronic device according to the embodiments of the present disclosure will be described with reference to Figure 10 The electronic device can be any one or both of the first device and the second device, or a single machine device independent of them, which can communicate with the first device and the second device to receive the collected input signals therefrom.

[0181] As Figure 10As shown, the electronic device includes one or more processors and a memory. The processor can be a central processing unit (CPU) or other form of processing unit having data processing and / or instruction execution capabilities, and can control other components in the electronic device to perform desired functions. The memory can include one or more computer program products that can include various forms of computer-readable storage media, such as volatile memory and / or non-volatile memory. The volatile memory, for example, can include random access memory (RAM), cache memory, and / or the like. The non-volatile memory, for example, can include read-only memory (ROM), hard disk, flash memory, and / or the like. One or more computer program instructions can be stored on the computer-readable storage media, and the processor can execute the program instructions to implement the method for diffracted wave imaging of subsurface discontinuous geological bodies according to various embodiments of the present disclosure described above and / or other desired functions.

[0182] In one example, the electronic device can further include an input device and an output device, which are interconnected through a bus system and / or other forms of connection mechanisms (not shown). In addition, the input device can include, for example, a keyboard, a mouse, and / or the like. The output device can output various information, including determined distance information, direction information, and / or the like, to the outside. The output device can include, for example, a display, a speaker, a printer, a communication network and a remote output device connected thereto, and / or the like.

[0183] Of course, in order to simplify, Figure 10 Only some of the components related to the present disclosure in the electronic device are shown in the figure, and components such as buses, input / output interfaces, and / or the like are omitted. In addition, the electronic device can include any other appropriate components according to specific application cases.

[0184] In addition to the above method and device, an embodiment of the present disclosure can also be a computer program product including computer program instructions, which, when executed by a processor, cause the processor to perform the steps in the method for diffracted wave imaging of subsurface discontinuous geological bodies according to various embodiments of the present disclosure described in the above part of the specification.

[0185] The computer program product can be written in any combination of one or more programming languages, including an object oriented programming language such as Java, C++, or the like, and conventional procedural programming languages, such as the "C" programming language or similar programming languages. The program code can execute entirely on the user's computing device, partly on the user's device, as a stand-alone software package, partly on the user's computing device and partly on a remote computing device or entirely on the remote computing device or server.

[0186] In addition, an embodiment of the present disclosure can also be a computer readable storage medium, which stores computer program instructions, and the computer program instructions, when executed by a processor, cause the processor to perform the steps in the method for diffracted wave imaging of subsurface discontinuous geological bodies according to various embodiments of the present disclosure described in the foregoing parts of the specification.

[0187] The computer readable storage medium can be any combination of one or more computer readable media. The computer readable medium can be a computer readable signal medium or a computer readable storage medium. The computer readable storage medium can include, for example, but not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, device, or apparatus, or any suitable combination of the above. More specific examples (a non-exhaustive list) of the computer readable storage medium include an electrical connection having one or more wires, a portable disc, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above.

[0188] Those of ordinary skill in the art can understand that all or part of the steps of the above-mentioned method embodiments can be completed by program instruction-related hardware, and the aforementioned program can be stored in a computer readable storage medium, and the program, when executed, executes steps including the above-mentioned method embodiments; and the aforementioned storage medium includes ROM, RAM, magnetic disc or optical disc and various storage medium that can store program code.

[0189] The above describes the basic principles of the present disclosure in combination with specific embodiments, but it should be noted that the advantages, advantages, effects and the like mentioned in the present disclosure are only examples and are not limiting, and these advantages, advantages, effects and the like cannot be considered as the various embodiments of the present disclosure must have. In addition, the above specific details are only for the purpose of example and for the purpose of understanding, and are not limited to the above specific details, and the above specific details do not limit the present disclosure to be necessarily implemented with the above specific details.

[0190] The various embodiments described in this specification are intended to be exemplary only. The phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of "including," "comprising," "having" and "containing" and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. The terms "connected," "coupled," and "pathway" are used broadly and encompass both direct and indirect connections, couplings and pathways.

[0191] The block diagrams of devices, apparatuses, equipment, systems referred to in this disclosure are only as illustrative examples and are not intended to require or imply that the connections, arrangements, configurations must be as shown in the block diagrams. These devices, apparatuses, equipment, systems can be connected, arranged, configured in any way as will be appreciated by those skilled in the art. Words such as "including," "containing," "comprising," and the like are to be construed in an inclusive fashion, meaning that "including," "containing," and "comprising," as well as other like terms are intended to be equivalent in meaning to "including, but not limited to." The terms "or," "and," and "and / or" as used herein, have the same meaning, and are to be taken as equivalent in meaning to the words "and / or." The term "such as" as used herein is to be taken as equivalent in meaning to the phrase "such as but not limited to."

[0192] The methods and apparatuses of this disclosure can be implemented in a number of ways. For example, the methods and apparatuses of this disclosure can be implemented using software, hardware, firmware, or any combination of these. The order of any steps described above is merely exemplary and the steps of the methods of this disclosure need not be performed in the order described unless otherwise specified. Furthermore, in some embodiments, the methods of this disclosure can also be implemented as a program for use with a computer system, the program including a machine-readable medium having stored program instructions that, when executed by a machine, cause the machine to perform the methods of this disclosure. Thus, the disclosure also covers a record medium storing the program for performing the methods of this disclosure.

[0193] It is also important to note that the devices, equipment and methods of this disclosure can be embodied in a variety of ways. These are intended to be equivalents in this disclosure.

[0194] The above description of the disclosed aspects is meant to be illustrative only and not limiting. Various modifications of these aspects will become apparent to those skilled in the art, and the generic principles defined herein can be applied to other aspects without departing from the scope of the disclosure. Accordingly, the disclosure is not intended to be limited to the aspects shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

[0195] The foregoing description has been presented for the purposes of illustration and description. Furthermore, the description is not intended to limit the embodiments of the disclosure to the forms disclosed herein. Although the various example aspects and embodiments have been described herein with regard to particular aspects and embodiments, those skilled in the art will recognize that certain modifications, changes, substitutions, additions and sub-combinations can be made without departing from the spirit of the disclosure.

Claims

1. A method for imaging a subsurface discontinuous geologic body with diffracted waves, characterized by, The method comprises: in response to obtaining a seismic data set associated with a target region of the underground and a migration velocity field, using the migration velocity field to migrate the seismic data set to obtain an angle domain imaging gather; wherein the target region of the underground includes a discontinuous geological body, the migration velocity field includes a plurality of migration velocities, each migration velocity is associated with parameters including a migrated position and a migrated time, and the angle domain imaging gather is associated with parameters including the migrated position, the migrated time and an observation dip angle, and the same migrated position and migrated time correspond to a plurality of different observation dip angles; using the angle domain imaging gather and a preset illumination angle calculation rule to calculate an illumination angle at an end point of a travel time curve matching each migration position; wherein the travel time curve is a travel time curve of a phase axis of a mixed wave in the angle domain imaging gather, and the mixed wave includes a reflected wave and a diffracted wave; for a migration angle gather matching each migrated position of the angle domain imaging gather, using the illumination angle at the end point of the travel time curve matching each migrated position to perform a hyperbolic pull and forward-backward transformation on the migration angle gather matching the same migrated position to obtain a diffracted wave signal corresponding to each migrated position; wherein the diffracted wave signal is associated with parameters including the migrated time and the observation dip angle; in response to constructing an angle domain diffracted wave imaging gather from the diffracted wave signal corresponding to each migrated position, using the observation dip angle to stack the angle domain diffracted wave imaging gather to obtain a diffracted wave imaging.

2. The method of claim 1, wherein, The seismic data set includes a plurality of seismic data, and each seismic data is associated with parameters including a pre-migration position and a pre-migration time; The method comprises: multiplying a preset amplification coefficient and the migration velocity field to obtain a new migration velocity field; wherein the preset amplification coefficient is greater than one; constructing a Kirchhoff integral kernel using the pre-migration position, the pre-migration time, the new migration velocity field, the migrated position and the migrated time; wherein the Kirchhoff integral kernel includes a travel time constraint kernel and an angle constraint kernel; performing double integration with respect to the pre-migration time and the pre-migration position to obtain the angle domain imaging gather, taking the product of the seismic data set and the Kirchhoff integral kernel as the integrated item.

3. The method of claim 2, wherein, The method comprises: constructing a travel time constraint kernel based on a Dirac function using the pre-migration position, the pre-migration time, the new migration velocity field, the migrated position and the migrated time; constructing an angle constraint kernel based on a Dirac function using the pre-migration position, the new migration velocity field, the migrated position and the migrated time; multiplying the travel time constraint kernel and the angle constraint kernel to obtain the Kirchhoff integral kernel.

4. The method of claim 2, wherein, The method comprises: stacking the angle domain imaging gathers with the observed dip angle to obtain a first migration profile; calculating a local dip angle matching each of the migration positions by using a plane wave destruction method based on the first migration profile; calculating a product of the local dip angle matching each of the migration positions and a corresponding new migration velocity, and dividing the product by two to obtain an illumination angle at an end point of a travel time curve matching each of the migration positions.

5. The method of claim 2, wherein, performing a hyperbolic pullback forward and inverse transform on the migration angle gathers matching the same migration position by using the illumination angle at the end point of the travel time curve matching each of the migration positions to obtain a diffraction wave signal corresponding to each of the migration positions, including: stacking the migration angle gathers matching each of the migration positions with the observed dip angle to obtain a second migration profile; performing a hyperbolic pullback forward transform on the second migration profile matching each of the migration positions based on the illumination angle at the end point of the travel time curve matching the migration position to obtain a pullback domain; wherein the pullback domain associated parameters include a hyperbolic curve vertex time and a curvature parameter; filtering out a part of the pullback domain corresponding to the curvature parameter less than zero to obtain a positive pullback domain; performing a hyperbolic pullback inverse transform on the positive pullback domain based on the illumination angle at the end point of the travel time curve matching each of the migration positions to obtain a primary diffraction wave signal corresponding to each of the migration positions; correcting the primary diffraction wave signal of each of the migration positions by using a first curve to obtain a diffraction wave signal corresponding to each of the migration positions; wherein the first curve is a diffraction wave in-phase axis travel time curve of the angle domain imaging gathers.

6. The method of claim 5, wherein, The correction of the primary diffraction wave signal of each of the migration positions by using the first curve includes: calculating a diffraction wave migration time correction amount of the primary diffraction wave signal corresponding to each of the migration positions by using a function representing the first curve; correcting a migration time associated with the matched primary diffraction wave signal by using the diffraction wave migration time correction amount to obtain a diffraction wave signal corresponding to each of the migration positions.

7. The method of claim 2, wherein, The construction of the angle domain diffraction wave imaging gathers according to the diffraction wave signals corresponding to each of the migration positions includes: determining a time sequence according to the migration time associated with the diffraction wave signal corresponding to each of the migration positions; sorting the diffraction wave signals corresponding to each of the migration positions according to the time sequence to obtain a diffraction wave signal sequence based on a time dimension; integrating the diffraction wave signal sequence into a data set to obtain the angle domain diffraction wave imaging gathers; wherein the associated parameters of the angle domain diffraction wave imaging gathers include a migration position, a migration time and an observed dip angle, and the same migration position and migration time correspond to multiple different observed dip angles.

8. The method of claim 7, wherein, The stacking of the angle domain diffraction wave imaging gathers with the observed dip angle to obtain a diffraction wave imaging includes: The angle domain diffraction imaging gathers are obtained by accumulating summation of the angle domain diffraction imaging gathers matched with different observation inclinations.

9. An apparatus for diffraction wave imaging of underground discontinuous geological bodies, characterized in that, The device comprises: The data migration unit is configured to, in response to obtaining a seismic data set associated with a target underground region and a migration velocity field, migrate the seismic data set by using the migration velocity field to obtain an angle domain imaging gather; wherein the target underground region comprises a discontinuous geological body, the migration velocity field comprises a plurality of migration velocities, each migration velocity is associated with a parameter comprising a migrated position and a migrated time, and the angle domain imaging gather is associated with a parameter comprising the migrated position, the migrated time and an observation inclination, and a same migrated position and migrated time correspond to a plurality of different observation inclinations. The illumination angle calculation unit is configured to calculate an illumination angle at an end point of a travel time curve matched with each migration position by using the angle domain imaging gather and a preset illumination angle calculation rule; wherein the travel time curve is a travel time curve of a phase axis of a mixed wave on the angle domain imaging gather, and the mixed wave comprises a reflected wave and a diffraction wave. The pull transformation unit is configured to, for a migration angle gather matched with each migrated position of the angle domain imaging gather, perform a hyperbolic pull forward and reverse transformation on the migration angle gather matched with a same migrated position by using the illumination angle at the end point of the travel time curve matched with each migrated position to obtain a diffraction wave signal corresponding to each migrated position; wherein the diffraction wave signal is associated with a parameter comprising the migrated time and an observation inclination. The diffraction wave imaging unit is configured to, in response to constructing an angle domain diffraction wave imaging gather from the diffraction wave signal corresponding to each migrated position, stack the angle domain diffraction wave imaging gather by using the observation inclination to obtain diffraction wave imaging.

10. An electronic device, comprising: The electronic device comprises: a processor; a memory for storing executable instructions of the processor; the processor is configured to read the executable instructions from the memory and execute the instructions to implement the method for diffraction wave imaging of a discontinuous geological body underground according to claims 1-8.

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