Automatic horizon tracking method and device and readable storage medium

Abstract

The invention provides an automatic horizon tracking method and device and a readable storage medium, and belongs to the technical field of geophysical exploration for petroleum. The method comprises the following steps: acquiring seismic data and the depth of the same layer in different input wells; based on the seismic data, determining a stratigraphic profile dip angle of each seismic trace; determining the initial horizon depth of each seismic channel based on the depths of the same horizon in different input wells; based on the stratigraphic section dip angle of each seismic channel and the initial horizon depth of each seismic channel, constructing an objective function by taking the depth of the same horizon in different input wells as a constraint condition; and performing iterative calculation on the target function, and iteratively updating the horizon depth of each seismic channel until the target function converges, and outputting the updated horizon depth of each seismic channel. The operation steps are simple, the continuity of the seismic horizon in the whole work area range and the consistency of well calibration horizon information can be considered, the tracking result is stable, the real horizon trend is fit, and the precision is high.

Description

Technical Field

[0001] The invention relates to the technical field of petroleum geophysical exploration, and in particular to an automatic layer tracking method, an automatic layer tracking device and a readable storage medium. Background Art

[0002] Identification and tracking of layers in seismic data is an important part of seismic exploration. Structural interpretation is the basic work of seismic interpretation. At the same time, structural interpretation is also a very important data basis in the process of seismic data processing. Take the depth domain modeling processing of seismic data as an example. Depth modeling often uses layer peeling method to model layer by layer from shallow to deep. Layer interpretation is the first important step of depth domain modeling. High-precision layer interpretation will greatly improve the accuracy and efficiency of velocity modeling.

[0003] At present, there are two commonly used methods for interpretation of horizons: manual picking and automatic tracking. Manual picking is to manually analyze the continuity of the event axis of the seismic profile, and then manually pick the horizon along the crest (or trough, zero amplitude line) of the seismic wavelet. Its advantage is that the interpretation results meet the user's expectations and are relatively intuitive. The disadvantage is that if you want to get high-precision picking results, the user's picking must be relatively dense, the workload of manual interpretation and horizon adjustment is very large, and the interpretation results are heavily dependent on the geological experience of the interpreter. As the area of ​​seismic exploration works becomes larger and larger, the volume of seismic data is also increasing. Relying solely on manual picking is not only a huge workload, but also still cannot efficiently obtain high-precision interpretation results. Automatic tracking interpretation is to track the horizon based on the similarity of adjacent seismic traces after a seed point is given. The specific process is to manually give a seed point, extract the horizon waveform according to a certain time window at the sampling position of the seed point, and search from the seed point to the adjacent seismic traces for a waveform segment similar to the seed point horizon waveform. The middle point corresponding to this waveform segment is the horizon depth tracked by the adjacent trace. This point can be used as a new seed point to search for the waveform of the next adjacent channel. This method is convenient and easy to operate, but the tracking result is easily affected by the seed point and the signal-to-noise ratio of the data. The tracking results of the same position using different seed points will be biased. There will be cross-axis and false faults far away from the initial artificial seed point, resulting in an incomplete layer plane in the automatic tracking result. The tracking range is not controlled, and manual intervention and correction cannot be made during the tracking process.

[0004] Although, a grid-based layer tracking method has been proposed. After the seismic data is gridded, it is automatically tracked within the grid, and then the grid tracking results are quality controlled and modified, and the grid correction tracking is reversed and continued forward. However, the above tracking method is not only complicated in operation steps, but also cannot take into account the continuity of the seismic layer in the entire work area and the consistency with the well calibration layer information, and the tracking results are often not stable enough, and there are often overall accuracy problems that are not consistent with the actual layer trend. Summary of the invention

[0005] The purpose of the embodiments of the present invention is to provide a method, device and readable storage medium for automatic layer tracking, so as to at least solve the problem that the above-mentioned existing layer tracking methods are not only complicated in operation steps, but also cannot take into account the continuity of the seismic layer in the entire work area and the consistency with the well calibration layer information, and the tracking results are often not stable enough, and the overall accuracy problem of not fitting the actual layer trend often occurs.

[0006] In order to achieve the above object, the present invention provides a first aspect of a layer automatic tracking method, the method comprising: Obtain seismic data and the depth of the same layer in different input wells; Based on the seismic data, determining the inclination angle of the stratigraphic section of each seismic trace; Determine the initial depth of each seismic trace based on the depth of the same layer in different input wells; Based on the dip angle of the stratigraphic profile of each seismic trace and the initial layer depth of each seismic trace, the objective function is constructed with the depth of the same layer in different input wells as the constraint condition; The objective function is iteratively calculated, and the layer depth of each seismic trace is iteratively updated until the objective function converges, and the updated layer depth of each seismic trace is output.

[0007] Optionally, determining the formation dip based on the seismic data includes: Based on the seismic data, obtaining seismic profile data; The seismic profile data is scanned for seismic dip angles to determine the dip angle of the stratum profile of each seismic trace in the seismic profile.

[0008] Optionally, the method further includes: The seismic profile data is subjected to noise removal and amplitude equalization processing.

[0009] Optionally, the input well includes a first input well and a second input well; Based on the depth of the same layer of the input well, determine the initial layer depth of each seismic trace, including:

[0010] in, For the i The initial horizon depth of the seismic trace; is the depth of the layer at the well location of the first input well; is the depth of the layer at the well location of the second input well; N is the number of seismic traces between the first input well and the second input well.

[0011] Optionally, the objective function is expressed as:

[0012]

[0013]

[0014] in, is the objective function; is the formation dip information matching function; N is the number of seismic traces between the first input well and the second input well; is the weight factor of the formation dip information matching function; For the i The initial horizon depth of the seismic trace; For the i - Initial horizon depth of 1 seismic trace; For the i The seismic trace i - lateral distance between 1 seismic trace; The first i The dip angle of the stratigraphic section of the seismic trace; is the damping function; is the weight factor of the damping function; For the i +1 Initial horizon depth of seismic trace.

[0015] Optionally, the constraint condition of the objective function is:

[0016] in, is the depth of the layer at the well location of the first input well; is the depth of the layer at the well location of the second input well.

[0017] Optionally, the objective function is iteratively calculated, and the layer depth of each seismic trace is iteratively updated until the objective function converges, and the updated layer depth of each seismic trace is output, including: The objective function is solved by using the least square method, and the layer depth of each seismic trace is updated in each iteration; When the objective function converges, the layer depth of each seismic trace updated in this iteration is output.

[0018] Optionally, the layer depth of each seismic trace is updated using the following formula:

[0019] in, For the m After +1 iteration i The depth of the horizon of the seismic trace; For the m After the iteration i The depth of the horizon of the seismic trace; For the m The depth correction amount of the layer after the iteration; is the depth of the layer at the well location of the first input well; is the depth of the layer at the well location of the second input well.

[0020] A second aspect of the present invention provides a layer automatic tracking device, the device comprising: Data acquisition module, used to obtain seismic data and the depth of the same layer in different input wells; A stratigraphic section dip angle determination module, used to determine the stratigraphic section dip angle of each seismic trace based on the seismic data; An initial layer depth determination module is used to determine the initial layer depth of each seismic trace based on the depth of the same layer in different input wells; An objective function construction module is used to construct an objective function based on the stratigraphic profile dip angle of each seismic trace and the initial layer depth of each seismic trace, taking the depth of the same layer in different input wells as a constraint condition; The layer depth output module is used to iteratively calculate the objective function and iteratively update the layer depth of each seismic trace until the objective function converges, and then output the updated layer depth of each seismic trace.

[0021] On the other hand, the present invention also provides a readable storage medium, on which instructions are stored, and the instructions are used to enable a machine to execute the above-mentioned automatic layer tracking method.

[0022] The operation steps of this technical solution are simple, and it can take into account the continuity of the seismic layer in the entire work area and the consistency with the well calibration layer information. The tracking results are stable and fit the actual layer trend, realizing efficient and high-precision automatic layer tracking.

[0023] Other features and advantages of the embodiments of the present invention will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The accompanying drawings are used to provide a further understanding of the embodiments of the present invention and constitute a part of the specification. Together with the following specific embodiments, they are used to explain the embodiments of the present invention, but do not constitute a limitation on the embodiments of the present invention. In the accompanying drawings: Figure 1 It is a flow chart of the layer automatic tracking method provided by the present invention; Figure 2 is a schematic diagram of a seismic profile provided by the present invention; Figure 3 It is a schematic diagram of the dip angle of the stratum section provided by the present invention; Figure 4 It is a schematic diagram of the initial layer depth provided by the present invention; Figure 5 is a schematic diagram of updated horizon depth provided by the present invention; Figure 6 It is a schematic diagram of the convergence of the objective function provided by the present invention; Figure 7 It is a structural schematic diagram of the layer automatic tracking device provided by the present invention.

[0025] Description of Reference Numerals 10-data acquisition module; 20-stratum profile dip determination module; 30-initial layer depth determination module; 40-objective function construction module; 50-layer bit depth output module. DETAILED DESCRIPTION

[0026] The specific implementation of the present invention is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described here is only used to illustrate and explain the present invention, and is not used to limit the present invention.

[0027] Figure 1 It is a flow chart of the layer automatic tracking method provided by the present invention; Figure 2 is a schematic diagram of a seismic profile provided by the present invention; Figure 3 It is a schematic diagram of the dip angle of the stratum section provided by the present invention; Figure 4 It is a schematic diagram of the initial layer depth provided by the present invention; Figure 5 is a schematic diagram of updated horizon depth provided by the present invention; Figure 6 It is a schematic diagram of the convergence of the objective function provided by the present invention; Figure 7 It is a structural schematic diagram of the layer automatic tracking device provided by the present invention.

[0028] like Figure 1 As shown, an embodiment of the present invention provides a layer automatic tracking method, the method comprising: Step 1: Obtain seismic data and the depth of the same layer in different input wells; In this example, seismic waves are excited to the surface and recorded, and seismic data collected in the field are processed according to a conventional seismic data processing procedure to obtain seismic data.

[0029] Step 2: determining the inclination angle of the stratigraphic profile of each seismic trace based on the seismic data; Specifically, in this embodiment, determining the formation dip based on the seismic data includes: Step 201, obtaining seismic profile data based on the seismic data; Step 202: Scan the seismic profile data for seismic dip angles to determine the dip angle of the stratum profile of each seismic trace in the seismic profile and record it as .

[0030] In another embodiment, after obtaining the seismic profile data in step 201, the method further includes: The seismic profile data is subjected to noise removal and amplitude equalization processing.

[0031] By adopting the above method, the interference of noise signals can be eliminated, the accuracy of data can be ensured, and the stratigraphic profile dip of each seismic channel obtained after seismic dip scanning can be more accurate, thereby improving the accuracy of layer tracking.

[0032] Step 3: Determine the initial layer depth of each seismic trace based on the depth of the same layer in different input wells; In this embodiment, according to the calibrated layer information of the input well, the depth information of the same layer at different input well positions is obtained. Taking two wells (the first input well and the second input well) as an example, assuming that the depth of a certain layer at the first input well position is , the depths at the first input well are ,based on and The initial value of the seismic layer depth is constructed by linear interpolation. Specifically, the initial layer depth of each seismic trace is calculated using the following calculation formula:

[0033]

[0034] in, For the i The initial horizon depth of the seismic trace; is the depth of the layer at the well location of the first input well; is the depth of the layer at the well location of the second input well;N is the number of seismic traces between the first input well and the second input well; i is the index of the seismic trace.

[0035] Step 4: Based on the inclination angle of the stratigraphic profile of each seismic trace and the initial layer depth of each seismic trace, the objective function is constructed with the depth of the same layer in different input wells as a constraint condition; In this embodiment, the depth of the same layer in different input wells is the well information matching information, and then an objective function based on the well information matching information and least squares optimization can be constructed. The expression of the objective function is:

[0036]

[0037]

[0038] in, is the objective function; is the formation dip information matching function; N is the number of seismic traces between the first input well and the second input well; is the weight factor of the formation dip information matching function; For the i The initial horizon depth of the seismic trace; For the i - Initial horizon depth of 1 seismic trace; For the i The seismic trace i - lateral distance between 1 seismic trace; The first i The dip angle of the stratigraphic section of the seismic trace; is the damping function; is the weight factor of the damping function; For the i +1 Initial horizon depth of seismic trace.

[0039] More specifically, It can be expressed as , which means that according to i The depth of the seismic trace and i -1 layer depth of seismic trace The calculated i The calculated dip angle of the trace is consistent with the i The dip angles of the stratigraphic sections of the seismic traces are compared iteratively; similarly, It can be expressed as , which means that according to i+1 seismic trace depth and i The depth of the seismic trace The calculated i The calculated dip angle of the +1 channel is consistent with the dip angle of the first channel in the seismic profile. i The dip angles of the stratigraphic sections of the seismic traces are compared iteratively.

[0040] The constraints of the objective function are:

[0041] in, is the depth of the layer at the well location of the first input well; is the depth of the layer at the well location of the second input well.

[0042] In this embodiment, the set constraint conditions can ensure that after the update, the depth of the same layer at the well position of the first input well and the depth at the well position of the second input well remain unchanged.

[0043] Step 5: Iteratively calculate the objective function and iteratively update the layer depth of each seismic trace until the objective function converges, and then output the updated layer depth of each seismic trace.

[0044] Specifically, the method comprises: solving the objective function by using the least square method, and updating the layer depth of each seismic trace in each iteration; When the objective function converges, the layer depth of each seismic trace updated in this iteration is output, and the updated layer depth of each seismic trace is obtained. Then, based on the layer depth of each seismic trace, the layer in the entire stratum can be obtained.

[0045] In this embodiment, the least squares iterative optimization is performed on the constructed initial layer depth using the objective function F. The first-order derivative of the objective function F with respect to the layer depth is calculated to construct the equation:

[0046] in, For the i The initial horizon depth of the seismic trace; i is 0,1,..., N -1;

[0047] The equation constructed by the first-order derivative is a nonlinear equation and can be solved by Newton's iteration method. First, use the initial value of the layer depth obtained above as Then, in each iteration m, the layer depth correction amount Accumulated to the current layer depth Get the updated layer depth:

[0048]

[0049] in, For the m After +1 iteration i The depth of the horizon of the seismic trace; For the m After the iteration i The depth of the horizon of the seismic trace; For the m The depth correction amount of the layer after the iteration; is the depth of the layer at the well location of the first input well; is the depth of the layer at the well location of the second input well.

[0050] Specifically, It can be obtained by solving the following five diagonal equations:

[0051]

[0052] in, is the objective function F The second derivative with respect to the layer depth, j is the index of the seismic trace. And, j The value of is: , therefore, through Be able to get The value of .

[0053] More specifically, in this embodiment, in order to reflect the technical advantages of the present invention, complex seismic data was used to perform effect testing. Figure 2 The seismic profile is shown after noise removal and amplitude equalization. The horizontal axis is the number of the seismic trace, and the vertical axis is the imaging depth. It can be seen that the data has a complex structure and has high and steep dip layers, which is very challenging. Figure 3 Yes Figure 2 The stratigraphic dip information obtained by scanning the seismic profile shown is the stratigraphic dip of each seismic trace, where the horizontal and vertical coordinate axes have the same meanings as Figure 2 , the figure shows the tangent value of the dip angle of the seismic section. Figure 4 It is the initial value of the seismic horizon depth constructed after the horizon depths of the two wells are given. It is obtained by linear interpolation based on the horizon depths of the two wells. The horizontal and vertical coordinate axes have the same meanings. Figure 2 The layer depth obtained by using the automatic tracking algorithm of the present invention is as follows: Figure 5As shown by the black solid line, it can be seen that the layer tracking accuracy is very high. The black solid line almost completely coincides with the crest of the seismic phase axis. Even in high and steep structures, the tracked layer is still highly consistent with the phase axis, which verifies the effectiveness and high accuracy of the algorithm. Figure 6 The figure shows the convergence of the least squares iteration objective function. The horizontal axis is the number of iterations, and the vertical axis is the objective function value. It can be seen that after 7 iterations, the objective function value meets the requirements. The running time is about 0.5 seconds, which meets the requirements of real-time interactive picking of layers. It realizes efficient and high-precision automatic layer tracking, overcoming the problems of poor stability and low precision of traditional methods.

[0054] like Figure 7 As shown, an embodiment of the present invention further provides a layer automatic tracking device, the device comprising: The data acquisition module 10 is used to obtain seismic data and the depth of the same layer in different input wells; A stratigraphic section dip angle determination module 20, configured to determine the stratigraphic section dip angle of each seismic trace based on the seismic data; An initial layer depth determination module 30 is used to determine the initial layer depth of each seismic trace based on the depth of the same layer in different input wells; An objective function construction module 40 is used to construct an objective function based on the stratigraphic profile dip angle of each seismic trace and the initial layer depth of each seismic trace, taking the depth of the same layer in different input wells as a constraint condition; The layer depth output module 50 is used to iteratively calculate the objective function and iteratively update the layer depth of each seismic trace until the objective function converges, and then output the updated layer depth of each seismic trace.

[0055] The embodiment of the present invention further provides a readable storage medium, on which instructions are stored, and the instructions are used to enable a machine to execute the above-mentioned layer automatic tracking method.

[0056] Those skilled in the art will understand that all or part of the steps in the method for implementing the above-mentioned embodiments can be completed by instructing the relevant hardware through a program, and the program is stored in a storage medium, including several instructions for making a single-chip microcomputer, a chip or a processor execute all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk and other media that can store program codes.

[0057] Those skilled in the art can clearly understand that for the convenience and simplicity of description, only the division of the above-mentioned functional units and modules is used as an example. In actual applications, the above-mentioned functions can be assigned to different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiments can be integrated into a processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The above-mentioned integrated unit can be implemented in the form of hardware or in the form of software functional units. In addition, the specific names of the functional units and modules are only for the convenience of distinguishing each other, and are not used to limit the scope of protection of this application.

[0058] The optional embodiments of the present invention are described in detail above in conjunction with the accompanying drawings. However, the embodiments of the present invention are not limited to the specific details in the above embodiments. Within the technical concept of the embodiments of the present invention, the technical scheme of the embodiments of the present invention can be subjected to a variety of simple modifications, and these simple modifications all belong to the protection scope of the embodiments of the present invention. It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the embodiments of the present invention will not further describe various possible combinations.

[0059] In addition, various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the embodiments of the present invention, they should also be regarded as the contents disclosed in the embodiments of the present invention.

Claims

1. A layer automatic tracking method, characterized in that: The method comprises: Obtain seismic data and the depth of the same layer in different input wells; Based on the seismic data, determining the inclination angle of the stratigraphic section of each seismic trace; Determine the initial depth of each seismic trace based on the depth of the same layer in different input wells; Based on the dip angle of the stratigraphic profile of each seismic trace and the initial layer depth of each seismic trace, the objective function is constructed with the depth of the same layer in different input wells as the constraint condition; The objective function is iteratively calculated, and the layer depth of each seismic trace is iteratively updated until the objective function converges, and the updated layer depth of each seismic trace is output.

2. The automatic layer tracking method according to claim 1, characterized in that: Determining the formation dip based on the seismic data includes: Based on the seismic data, obtaining seismic profile data; The seismic profile data is scanned for seismic dip angles to determine the dip angle of the stratum profile of each seismic trace in the seismic profile.

3. The automatic layer tracking method according to claim 2, characterized in that: The method further comprises: The seismic profile data is subjected to noise removal and amplitude equalization processing.

4. The automatic layer tracking method according to claim 1, characterized in that: The input wells include a first input well and a second input well; Based on the depth of the same layer of the input well, determine the initial layer depth of each seismic trace, including: in, For the i The initial horizon depth of the seismic trace; is the depth of the layer at the well location of the first input well; is the depth of the layer at the well location of the second input well; N is the number of seismic traces between the first input well and the second input well.

5. The automatic layer tracking method according to claim 4, characterized in that: The expression of the objective function is: in, is the objective function; is the formation dip information matching function; N is the number of seismic traces between the first input well and the second input well; is the weight factor of the formation dip information matching function; For the i The initial horizon depth of the seismic trace; For the i - Initial horizon depth of 1 seismic trace; For the i The seismic trace i - lateral distance between 1 seismic trace; The first i The dip angle of the stratigraphic section of the seismic trace; is the damping function; is the weight factor of the damping function; For the i +1 Initial horizon depth of seismic trace.

6. The automatic layer tracking method according to claim 4, characterized in that: The constraints of the objective function are: in, is the depth of the layer at the well location of the first input well; is the depth of the layer at the well location of the second input well.

7. The automatic layer tracking method according to claim 1, characterized in that: Iteratively calculating the objective function and iteratively updating the layer depth of each seismic trace until the objective function converges, and outputting the updated layer depth of each seismic trace, including: The objective function is solved by using the least square method, and the layer depth of each seismic trace is updated in each iteration; When the objective function converges, the layer depth of each seismic trace updated in this iteration is output.

8. The automatic layer tracking method according to claim 1, characterized in that: The layer depth of each seismic trace is updated using the following formula: in, For the m After +1 iteration i The depth of the horizon of the seismic trace; For the m After the iteration i The depth of the horizon of the seismic trace; For the m The depth correction amount of the layer after the iteration; is the depth of the layer at the well location of the first input well; is the depth of the layer at the well location of the second input well.

9. A layer automatic tracking device, characterized in that: The device comprises: Data acquisition module, used to obtain seismic data and the depth of the same layer in different input wells; A stratigraphic section dip angle determination module, used to determine the stratigraphic section dip angle of each seismic trace based on the seismic data; An initial layer depth determination module is used to determine the initial layer depth of each seismic trace based on the depth of the same layer in different input wells; An objective function construction module is used to construct an objective function based on the stratigraphic profile dip angle of each seismic trace and the initial layer depth of each seismic trace, taking the depth of the same layer in different input wells as a constraint condition; The layer depth output module is used to iteratively calculate the objective function and iteratively update the layer depth of each seismic trace until the objective function converges, and then output the updated layer depth of each seismic trace.

10. A readable storage medium having instructions stored thereon, wherein the instructions are used to enable a machine to execute the automatic layer tracking method described in any one of claims 1 to 8.

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