A method and apparatus for converting a time domain seismic profile into a depth domain seismic profile

Abstract

The application provides a method and device for converting a time domain seismic profile into a depth domain seismic profile, which comprises the following steps: reading time domain seismic profile data, interpreting a geological horizon of the time domain seismic profile, and dividing strata in the time domain into a plurality of strata segments; obtaining a seismic-logging time-depth relationship calibration list according to geological layering data of a logging curve and geological horizon interpretation data, calculating average velocities of each stratum and average velocity errors of stratum velocities at each well; updating a time domain stratum velocity field matrix according to the average velocity errors of the strata and the average velocity field, and drawing a depth domain seismic profile. The application more directly interprets seismic data in the depth domain, realizes a programmed processing mode of the average velocity field of the strata and correction, greatly reduces the workload of time-depth relationship correction and depth domain structure mapping, is convenient for directly mapping, and also provides support for carrying out other related geological researches.

Description

Technical Field

[0001] This invention belongs to the field of petroleum exploration and development, and specifically relates to a method and apparatus for converting time-domain seismic profiles into depth-domain seismic profiles. Background Technology

[0002] Seismic profiles are an effective way to understand underground strata structure and geological information. Generally, seismic waves are obtained by artificially generating seismic sources near the Earth's surface and transmitting them into the underground space. During their propagation, when these waves encounter interfaces formed by heterogeneous variations in strata or lithology (i.e., impedance differences exist on both sides of the interface), reflection, scattering, diffraction, and transmission occur. When these anomalous fluctuations are ultimately reflected back to the surface, they are received by an array of seismic sensors deployed on the ground, forming a seismic reception record. These raw seismic reception records, through specific processing procedures and imaging techniques, can be transformed into seismic profiles containing underground reflection information. By conducting geological interpretation of these seismic profiles, we can understand the structural morphology changes of underground strata, and even the patterns of changes in underground lithology and porosity.

[0003] However, these seismic profiles typically reflect time-domain information vertically, not true subsurface depth information, leading to a certain degree of error between the two. Therefore, the geological structural information obtained from time-domain seismic profiles ultimately needs to be converted to the depth domain for interpretation. Conventional seismic interpretation methods require stratigraphic interpretation on time-domain seismic profiles, followed by artificial seismic composite record calibration using drilling and logging data to determine the depth of each stratigraphic interface at the wellhead and its corresponding temporal relationship with the seismic profile's phase axis. Then, for a specific stratum, the formation average velocity at the logging points is calculated based on the time-depth relationship calibrated from each well, and interpolation is performed across the entire area to obtain a region-wide average velocity distribution map. Finally, the two-way reflection time of the interpreted stratum is extracted from the average velocity distribution map, and the corresponding depth structural map of the geological stratum is calculated. This method can only calculate the depth structural map of one set of strata at a time; for multiple sets of strata, the mapping process needs to be repeated multiple times, and the mapping process is quite cumbersome. In addition, the obtained structural maps do not contain detailed features of wave group relationships on the seismic profiles, but only reflect the depth variation information of stratigraphic interfaces, which is not conducive to fully exploring other geological information hidden in the seismic profiles. Summary of the Invention

[0004] To address the issue that conventional time-domain seismic tectonic interpretation is not conducive to directly obtaining stratigraphic depth information, and that the process of creating multiple stratigraphic maps is cumbersome and inconvenient, this application provides a method and apparatus for converting time-domain seismic profiles into depth-domain seismic profiles, so as to facilitate direct structural mapping and also provide support for carrying out other related geological studies.

[0005] In a first aspect, embodiments of this application provide a method for converting a time-domain seismic profile into a depth-domain seismic profile, comprising: reading time-domain seismic profile data; interpreting the geological stratigraphy of the time-domain seismic profile; dividing the strata into several stratigraphic segments in the time domain; obtaining a seismic-well logging time-depth relationship calibration list based on the geological stratigraphic data and geological stratigraphic interpretation data from well logging curves; calculating the average velocity of each stratum and the error between the stratum velocity at each well and the average velocity of the stratum; updating the time-domain stratum velocity field matrix based on the average velocity error and the average velocity field; and drawing the depth-domain seismic profile.

[0006] In some embodiments, reading time-domain seismic profile data and interpreting the geological stratigraphy of the time-domain seismic profile, dividing the strata into several stratigraphic segments in the time domain, includes: creating an empty matrix of the same size as the time-domain seismic profile, which is represented as an initial stratigraphic segment matrix and an initial velocity field matrix.

[0007] In some embodiments, reading time-domain seismic profile data, interpreting the geological stratigraphy of the time-domain seismic profile, and dividing the strata into several stratigraphic segments in the time domain further includes: obtaining time-domain information of underground geological interfaces through the interpretation of the stratigraphy of the time-domain seismic profile, dividing the strata into several stratigraphic segments in the time domain according to the geological interface information, forming a stratigraphic segmentation matrix, and assigning values ​​to the stratigraphic segment matrix.

[0008] In some embodiments, obtaining a seismic-well logging time-depth relationship calibration list based on the geological stratification data and geological stratum interpretation data of the well logging curves, and calculating the average velocity of each stratum and the formation velocity error at each well, includes: calibrating the geological stratification data of each well logging curve based on the well logging stratification information and the artificial seismic synthetic record.

[0009] In some embodiments, obtaining a seismic-well logging time-depth relationship calibration list based on geological stratification data and geological stratigraphic interpretation data from well logging curves, and calculating the average velocity of each stratum and the formation velocity error at each well, further includes: obtaining a seismic-well logging time-depth relationship calibration list based on geological stratification data and geological stratigraphic interpretation data from well logging curves, and calculating the average velocity of each stratum, using the following formula:

[0010]

[0011] Where w is the well number, W is the total number of wells, dtop(w, i) represents the depth of the i-th formation in well w, dtop(w, i+1) represents the depth of the (i+1)-th formation in well w, ttop(w, i) represents the two-way reflection time of the i-th formation in well w, ttop(w, i+1) represents the two-way reflection time of the (i+1)-th formation in well w, and Vavg(i+1) represents the average velocity of the (i+1)-th formation group.

[0012] The formula for calculating the error between the formation velocity at each well and the formation average velocity is:

[0013]

[0014] Wherein, dtop(w,i) represents the depth of the i-th formation in well w, dtop(w,i+1) represents the depth of the (i+1)-th formation in well w, ttop(w,i) represents the two-way reflection time of the i-th formation in well w, ttop(w,i+1) represents the two-way reflection time of the (i+1)-th formation in well w, Vavg(i+1) represents the average velocity of the (i+1)-th formation group, and Vσ(nw,i+1) represents the error between the location (track number nw) of well w and the (i+1)-th formation and the average velocity.

[0015] In some embodiments, updating the time-domain formation velocity field matrix and drawing a depth-domain seismic profile based on the formation mean velocity error and mean velocity field includes: correcting the velocity error of each formation in each well based on the mean velocity field and the influence radius of each well, and updating the time-domain formation velocity field matrix, as shown in the formula:

[0016]

[0017] radius represents the influence radius of each well, and V(m,n) is the updated velocity matrix.

[0018] In some embodiments, updating the time-domain formation velocity field matrix based on the formation average velocity error and the average velocity field, and drawing the depth-domain seismic profile further includes: converting the time interval sampling interval of the seismic profile into a cumulative depth value based on the formation velocity field matrix, moving the value of that point on the seismic profile to the corresponding depth position, and drawing the depth profile.

[0019] Secondly, embodiments of this application provide an apparatus for converting a time-domain seismic profile into a depth-domain seismic profile, comprising: an interpretation unit for reading time-domain seismic profile data, performing geological stratigraphic interpretation on the time-domain seismic profile, and dividing the strata into several stratigraphic segments in the time domain; a calculation unit for obtaining a seismic-well logging time-depth relationship calibration list based on the geological stratigraphic data and geological stratigraphic interpretation data from well logging curves, calculating the average velocity of each stratum and the error between the formation velocity at each well and the average velocity of the formation; and a plotting unit for updating the time-domain formation velocity field matrix based on the formation average velocity error and the average velocity field, and plotting the depth domain for the seismic profile.

[0020] Thirdly, embodiments of this application provide a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of any of the methods described above.

[0021] Fourthly, embodiments of this application 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 program to implement the steps of any of the methods described above.

[0022] The method and apparatus for converting time-domain seismic profiles into depth-domain seismic profiles according to the embodiments of this application have the following beneficial effects:

[0023] This application utilizes stratigraphic interpretation and well logging stratification information to transform time-domain seismic profiles into depth-domain seismic profiles, facilitating more intuitive interpretation of seismic data in the depth domain. It also realizes a procedural processing method for stratigraphic mean velocity field and correction, greatly reducing the workload of time-depth relationship correction and depth-domain construction mapping, and making it easier to directly construct maps. Attached Figure Description

[0024] Figure 1 This is a schematic flowchart illustrating the method for converting time-domain seismic profiles into depth-domain seismic profiles according to an embodiment of this application.

[0025] Figure 2 This is another flowchart illustrating the method for converting time-domain seismic profiles into depth-domain seismic profiles according to an embodiment of this application.

[0026] Figure 3 This is a time-domain seismic profile of an embodiment of this application;

[0027] Figure 4 For the embodiments of this application Figure 3 Seismic interpretation layers and well logging stratification;

[0028] Figure 5 This is the basis for the embodiments of this application. Figure 4 The obtained time-domain formation velocity model V(m, n);

[0029] Figure 6 This is the basis for the embodiments of this application. Figure 5 Velocity information is converted into a depth-domain seismic profile (displaying well logging and depth-domain layered data);

[0030] Figure 7 This is the basis for the embodiments of this application. Figure 5 Velocity information is converted into a depth-domain seismic profile (well logging and depth-domain layered data are not displayed);

[0031] Figure 8 This is a diagram of a device for converting a time-domain seismic profile into a depth-domain seismic profile according to an embodiment of this application. Detailed Implementation

[0032] The present application will be further described below with reference to the accompanying drawings and embodiments.

[0033] In the following description, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. The following description provides multiple embodiments of the invention, which can be substituted or combined with each other. Therefore, this application can also be considered to include all possible combinations of the same and / or different embodiments described. Thus, if one embodiment includes features A, B, and C, and another embodiment includes features B and D, then this application should also be considered to include embodiments containing one or more other possible combinations of features A, B, C, and D, even if such embodiments are not explicitly described in the following text.

[0034] Example 1

[0035] like Figure 1 As shown, the method for converting a time-domain seismic profile into a depth-domain seismic profile in this application includes: S101, reading the time-domain seismic profile data, interpreting the geological stratigraphy of the time-domain seismic profile, and dividing the strata into several stratigraphic segments in the time domain; S103, obtaining a time-depth relationship calibration list of seismic-well logging based on the geological stratigraphic data and geological stratigraphic interpretation data of the well logging curves, and calculating the average velocity of each stratum and the error between the formation velocity at each well and the average velocity of the formation; S105, updating the time-domain formation velocity field matrix based on the formation average velocity error and the average velocity field, and drawing the depth-domain seismic profile.

[0036] This application utilizes stratigraphic interpretation and well logging layering information to transform time-domain seismic profiles into depth-domain seismic profiles, enabling more intuitive interpretation of seismic data in the depth domain. It also realizes a procedural processing method for stratigraphic mean velocity field and correction, greatly reducing the workload of time-depth relationship correction and depth-domain structural mapping, saving time and improving efficiency.

[0037] Example 2

[0038] like Figure 2-7 As shown, the method for converting time-domain seismic profiles into depth-domain seismic profiles in this application includes:

[0039] Step 1: Read the time-domain seismic profile data, which is usually an m×n matrix array, denoted by ST(u, v), where u and v are the coordinate indices of the matrix array ST, u∈[1, m], v∈[1, n];

[0040] Step 2: Based on the size of the time-domain seismic profile, create empty matrices Z(m,n) and V(m,n) with the same size as the time-domain seismic profile, representing the stratigraphic group matrix and the initial velocity field matrix, respectively, with initial values ​​set to 0; the created initial velocity field matrix and stratigraphic group matrix are used to store the stratigraphic velocity and stratigraphic group information at the corresponding locations of the time-domain seismic profile.

[0041] Step 3: Perform geological stratigraphic interpretation on the time-domain seismic profile to obtain a list of geological stratigraphic information T(horizon, n, ttop), where horizon represents the stratigraphic name, n represents the seismic trace number, and ttop represents the two-way reflection time of the horizon stratum at the nth trace location; through time-domain seismic interpretation (stratigraphic tracing), obtain the time-domain information of subsurface geological interfaces, and based on the geological interface information, divide the strata into several stratigraphic segments in the time domain, that is, the vertically adjacent geological interfaces are the same strata, and it is assumed that they have the same stratigraphic velocity.

[0042] Step 4: Using artificial seismic synthetic records, the geological stratification data of each logging curve is calibrated to obtain the geological stratification information table D(well, nw, horizon, dtop) for each logging, where well represents the well name, nw represents the seismic trace number corresponding to the wellhead location, horizon represents the stratum name, and dtop represents the absolute elevation depth of the horizon stratum corresponding to the well.

[0043] Step 5: Through the joint analysis of Step 3 and Step 4, obtain the time-depth relationship calibration list TD (well, horizon, ttop, dtop) of seismic-well logging;

[0044] Step 6: Assign values ​​to the stratigraphic group matrix Z(m,n). Assume there are k stratigraphic interpretation boundaries (horizons), numbered sequentially from top to bottom as 1, 2, ..., k. The corresponding stratigraphic group numbers are 1, 2, ..., k, k+1. The stratigraphic group numbered above the first horizontal boundary is 1; the stratigraphic group numbered between horizontal boundaries i and i+1 is i+1; and the stratigraphic group numbered below the last horizontal boundary k is k+1. For each seismic trace n, determine the location of the stratigraphic boundary m according to the above numbering rules, and assign values ​​to Z(m,n).

[0045] Step 7: Using the time-depth TD relationship table for each well obtained in Step 5, calculate the average velocity of each formation. The calculation method is as follows:

[0046]

[0047] Where w is the well number, W is the total number of wells, dtop(w, i) represents the depth of the i-th formation in well w, dtop(w, i+1) represents the depth of the (i+1)-th formation in well w, ttop(w, i) represents the two-way reflection time of the i-th formation in well w, ttop(w, i+1) represents the two-way reflection time of the (i+1)-th formation in well w, and Vavg(i+1) represents the average velocity of the (i+1)-th formation group.

[0048] Step 8: Calculate the error between the formation velocity at each well and the average formation velocity obtained in Step 7. The calculation method is as follows:

[0049]

[0050] Where dtop(w,i), dtop(w,i+1), ttop(w,i), ttop(w,i+1), and Vavg(i+1) are the same as the formula annotation in step 7, and Vσ(nw,i+1) represents the error between the i+1 formation at the w-th well location (nw) and the average velocity.

[0051] Step 9: Update the formation average velocity field matrix V(m,n). Based on the average velocity field, and according to the influence radius of each well, correct the velocity error of each well and each formation. The calculation formula is as follows:

[0052]

[0053] radius represents the influence radius of each well, and V(m,n) is the updated velocity matrix.

[0054] Step 10: Depth Domain Seismic Profile Relocation Calculation. For each seismic trace n in the time domain ST(m,n), calculate the cumulative depth of each sampling point m in seismic trace n using the velocity value at the corresponding location of V(m,n), then move the ST(m,n) values ​​to the corresponding depth, and redraw the depth profile.

[0055] In this application, based on well logging stratification information and artificial seismic synthetic record calibration information, the layer velocity at each wellhead location is calculated for that geological stratum. The layer velocities calculated from all wells in that stratum are summed and divided by the number of wellheads to obtain the formation average velocity for that stratum. Then, the formation average velocity is subtracted from the formation velocity calculated at each wellhead location for that stratum to obtain the velocity residual at each wellhead location in that stratum. The formation average velocity is updated using the velocity residual and the wellhead influence radius to obtain the time-domain formation velocity field matrix. Finally, based on the formation velocity field matrix, for each seismic trace data (vertical direction), the sampling interval of the seismic profile at equal time intervals is converted into a cumulative depth value, and the value at that point on the seismic profile is moved to the corresponding depth location.

[0056] The method proposed in this application for converting time-domain seismic profiles into depth-domain seismic profiles allows for a more intuitive interpretation of seismic data in the depth domain. It also enables a procedural processing method for formation mean velocity fields and corrections, significantly reducing the workload of time-depth relationship correction and depth-domain structural mapping, and improving work efficiency.

[0057] Example 3

[0058] like Figure 8As shown, this application provides an apparatus for converting a time-domain seismic profile into a depth-domain seismic profile, comprising: an interpretation unit 10, used to read time-domain seismic profile data, perform geological stratigraphic interpretation on the time-domain seismic profile, and divide the strata into several stratigraphic segments in the time domain; a calculation unit 20, used to obtain a time-depth relationship calibration list of seismic-well logging based on the geological stratigraphic data and geological stratigraphic interpretation data of the well logging curves, and calculate the average velocity of each stratum and the error between the formation velocity at each well and the average velocity of the formation; and a plotting unit 30, used to update the time-domain formation velocity field matrix based on the formation average velocity error and the average velocity field, and plot the depth-domain seismic profile.

[0059] In this application, the embodiment of the device for converting time-domain seismic profiles into depth-domain seismic profiles is basically similar to the embodiment of the method for converting time-domain seismic profiles into depth-domain seismic profiles. For relevant details, please refer to the description of the embodiment of the method for converting time-domain seismic profiles into depth-domain seismic profiles.

[0060] This application also provides a computer device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the program, it implements the above-described method steps for converting a time-domain seismic profile into a depth-domain seismic profile.

[0061] This invention also provides a computer-readable storage medium storing a computer program thereon, which, when executed by a processor, implements the method steps described above for converting a time-domain seismic profile into a depth-domain seismic profile. The computer-readable storage medium may include, but is not limited to, any type of disk, including floppy disks, optical disks, DVDs, CD-ROMs, microdrives, as well as magneto-optical disks, ROMs, RAMs, EPROMs, EEPROMs, DRAMs, VRAMs, flash memory devices, magnetic cards or optical cards, nanosystems (including molecular memory ICs), or any type of medium or device suitable for storing instructions and / or data.

[0062] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for converting a time-domain seismic profile into a depth-domain seismic profile, characterized in that, include: Read time-domain seismic profile data, interpret the geological stratigraphy of the time-domain seismic profile, and divide the strata into several stratigraphic segments in the time domain; Based on the geological stratification data and geological stratigraphic interpretation data of the well logging curves, a time-depth relationship calibration list of seismic-well logging is obtained, and the average velocity of each stratum and the error between the formation velocity at each well and the average velocity of the formation are calculated. Based on the average velocity error and average velocity field of the formation, update the time-domain formation velocity field matrix and draw the depth-domain seismic profile. Based on the geological stratification data and geological stratigraphic interpretation data from the well logging curves, a time-depth relationship calibration list for seismic-well logging is obtained. The average velocity of each stratum and the error between the formation velocity at each well and the average formation velocity also include: obtaining the time-depth relationship calibration list for seismic-well logging based on the geological stratification data and geological stratigraphic interpretation data from the well logging curves, and calculating the average velocity of each stratum, using the following formula: Where w is the well number, W is the total number of wells, dtop(w, i) represents the depth of the i-th formation in well w, dtop(w, i+1) represents the depth of the (i+1)-th formation in well w, ttop(w, i) represents the two-way reflection time of the i-th formation in well w, ttop(w, i+1) represents the two-way reflection time of the (i+1)-th formation in well w, and Vavg(i+1) represents the average velocity of the (i+1)-th formation group. The formula for calculating the error between the formation velocity at each well and the formation average velocity is: Where Vσ(nw, i+1) represents the location of the w-th well, the tunnel number nw, and the error between the i+1-th formation and the average velocity; Based on the formation mean velocity error and mean velocity field, the time-domain formation velocity field matrix is ​​updated, and the depth-domain seismic profile is drawn. This includes: based on the mean velocity field, correcting the velocity error of each formation in each well according to the influence radius of each well, and updating the time-domain formation velocity field matrix. The formula is as follows: Where Vavg(i) is the average velocity field, n is the seismic trace number, radius is the influence radius of each well, and V(m,n) is the updated velocity matrix.

2. The method for converting a time-domain seismic profile into a depth-domain seismic profile according to claim 1, characterized in that, Read time-domain seismic profile data, interpret the geological stratigraphy of the time-domain seismic profile, and divide the strata into several stratigraphic segments in the time domain. This includes creating an empty matrix of the same size as the time-domain seismic profile, which is represented as the initial stratigraphic segment matrix and the initial velocity field matrix.

3. The method for converting a time-domain seismic profile into a depth-domain seismic profile according to claim 2, characterized in that, Reading time-domain seismic profile data, interpreting the geological stratigraphy of the time-domain seismic profile, and dividing the strata into several stratigraphic segments in the time domain also includes: obtaining time-domain information of underground geological interfaces through the interpretation of the stratigraphy of the time-domain seismic profile, dividing the strata into several stratigraphic segments in the time domain based on the geological interface information, constructing a stratigraphic segment division matrix, and assigning values ​​to the stratigraphic segment division matrix.

4. The method for converting a time-domain seismic profile into a depth-domain seismic profile according to any one of claims 1-3, characterized in that, Based on the geological stratification data and geological stratigraphic interpretation data of the well logging curves, a time-depth relationship calibration list of seismic-well logging is obtained. The average velocity of each stratum and the error between the formation velocity at each well and the average velocity of the formation are calculated. This includes: calibrating the geological stratification data of each well logging curve based on well logging stratification information and artificial seismic synthetic records.

5. The method for converting a time-domain seismic profile into a depth-domain seismic profile according to any one of claims 1-3, characterized in that, The process of updating the time-domain stratum velocity field matrix based on the stratum average velocity error and average velocity field, and drawing the depth-domain seismic profile, also includes: converting the time interval sampling interval of the seismic profile into cumulative depth values ​​based on the stratum velocity field matrix, moving the values ​​of points on the seismic profile to the corresponding depth positions, and drawing the depth profile.

6. A device for converting time-domain seismic profiles into depth-domain seismic profiles, characterized in that, An apparatus for performing a method for converting a time-domain seismic profile into a depth-domain seismic profile as described in any one of claims 1-5, the apparatus comprising: The interpretation unit is used to read time-domain seismic profile data, interpret the geological stratigraphy of the time-domain seismic profile, and divide the strata into several stratigraphic segments in the time domain. The calculation unit is used to obtain a time-depth relationship calibration list of seismic-well logging based on the geological stratification data and geological stratum interpretation data of the well logging curves, and to calculate the average velocity of each stratum and the error between the formation velocity at each well and the average velocity of the formation. The plotting unit updates the time-domain stratum velocity field matrix based on the stratum mean velocity error and mean velocity field, and plots the depth domain for seismic profiles.

7. A computer-readable storage medium having a computer program stored thereon, characterized in that, When executed by a processor, the program implements the steps of the method described in any one of claims 1-5.

8. 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 program, it implements the steps of the method according to any one of claims 1-5.

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