CN115598699A - Pre-stack time migration method, device, equipment and medium for uplink wave seismic data - Google Patents
Pre-stack time migration method, device, equipment and medium for uplink wave seismic data Download PDFInfo
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Abstract
The disclosure provides a prestack time migration method and device for uplink wave seismic data, and belongs to the technical field of seismic exploration. The method comprises the following steps: calculating the travel time of each upgoing wave seismic data from the shot point to the imaging point according to the root-mean-square speed of the imaging point with the sea level as a reference surface; calculating the travel time of each uplink wave seismic data from the imaging point to the corresponding wave detection point according to the root-mean-square speed of the imaging point with the sea level as a reference surface; and taking the sum of the calculated travel time of each upgoing wave seismic data from the shot point to the imaging point and the calculated travel time from the imaging point to the corresponding demodulator probe as the travel time of each upgoing wave seismic data. In the embodiment of the disclosure, when the travelling time of the upgoing wave seismic data is calculated by uniformly taking the sea level as the reference surface, the calculated travelling time of the upgoing wave seismic data can be more accurate, and the migration precision of the upgoing wave seismic data is improved.
Description
Technical Field
The present disclosure relates to the field of seismic exploration, and in particular, to a method, an apparatus, a device, and a medium for prestack time migration of uplink seismic data.
Background
In the technical field of seismic exploration, prestack time migration is an important method for imaging seismic waves, and the principle of the method is that a plurality of seismic data acquired at the sea bottom are migrated to the position of a real imaging point to form a common imaging point seismic data gather and then are stacked, so that the imaging precision of an underground medium is improved. The travel time of the up-going wave seismic data is used in the migration of the seismic data. The propagation path of the upgoing wave seismic data comprises two sections from a shot point to an imaging point and from the imaging point to a demodulator probe, and the travel time of the upgoing wave seismic data is the time length for the upgoing wave seismic data to propagate from the shot point to the demodulator probe according to the propagation path.
In the related art, the travel time of the up-going seismic data is calculated using the following formula:
In the formula, t is the one-way vertical time with sea level as a reference plane corresponding to the imaging point, x s Horizontal distance, x, from shot to imaging point g Is the horizontal distance from the demodulator probe to the imaging point, d isDepth of sea floor, v, at which the point of detection is located s Is the root mean square velocity, v, of the corresponding sea level as a reference plane at the imaging point w Velocity of sea water, v r The root mean square velocity corresponding to the imaging point with the sea bottom surface as a reference surface is obtained.
In the course of implementing the present disclosure, the inventors found that the prior art has at least the following problems:
v in formula for calculating travel time from imaging point to demodulator point w Is the speed, v, of the sea water based on sea level r Root mean square velocity at the imaging point with the sea bottom surface as the reference surface, t is the one-way vertical time with the sea level as the reference surface at the imaging point, v w 、v r And t use different reference planes. When solving the right triangle formula, (t-d/v) w ) And (x) s /v r ) The calculated travel time from the imaging point to the wave detection point is inaccurate due to different reference surfaces, so that the calculated travel time of the uplink wave seismic data is inaccurate, and the migration precision of the uplink wave seismic data is influenced.
Disclosure of Invention
The embodiment of the disclosure provides a prestack time migration method and a prestack time migration device for up-going wave seismic data, which can improve the accuracy of traveling time of up-going wave seismic data, and further improve the migration precision of up-going wave seismic data. The technical scheme is as follows:
in a first aspect, a method for prestack time migration of upgoing seismic data is provided, the method comprising:
acquiring seismic data acquired by acquisition equipment at a plurality of wave detection points, wherein the plurality of wave detection points are positioned on the sea bottom surface, each wave detection point is provided with one acquisition equipment, the acquisition equipment is used for acquiring seismic waves emitted by emission equipment at a shot point and reflected by a seabed stratum to obtain the seismic data, and the shot point is positioned on the sea level; obtaining multi-channel uplink wave seismic data based on the seismic data; calculating the travel time of each upgoing wave seismic data from the shot point to the imaging point according to the root-mean-square speed of the imaging point with the sea level as a reference surface; calculating the travel time of each uplink wave seismic data from the imaging point to the corresponding wave detection point according to the root-mean-square speed of the imaging point with the sea level as a reference surface; taking the sum of the calculated travel time of each upgoing wave seismic data from the shot point to the imaging point and the calculated travel time of each upgoing wave seismic data from the imaging point to the corresponding demodulator probe as the travel time of each upgoing wave seismic data; and shifting the plurality of channels of upgoing wave seismic data according to the calculated travel time of each channel of upgoing wave seismic data.
Optionally, the calculating, according to the root-mean-square velocity at an imaging point with sea level as a reference plane, a travel time of each of the upgoing seismic data from the shot point to the imaging point includes: calculating the travel time of each said upgoing seismic data from said shot to said imaging point according to the following formula:
wherein, t S For the travel time of each upgoing wave seismic data from the shot point to the imaging point, t is the one-way vertical time with the sea level as the reference plane corresponding to the imaging point, x s And v is the horizontal distance from the shot point to the imaging point, and the root mean square velocity corresponding to the imaging point and taking the sea level as a reference surface.
The calculating the travel time of each uplink wave seismic data from the imaging point to the corresponding wave detection point according to the root-mean-square velocity of the imaging point with the sea level as a reference surface comprises the following steps: calculating the travel time of each upgoing wave seismic data from the imaging point to the corresponding demodulator probe according to the following formula:
wherein, t G For each travel time, x, of the upgoing seismic data from the imaging point to the corresponding geophone point g Corresponding detection is carried out on each up-travelling wave seismic dataThe horizontal distance from the wave point to the imaging point, d is the depth of the sea bottom where the wave detection point is located, v is the root-mean-square speed which takes the sea level as a reference plane and corresponds to the imaging point, and t is the one-way vertical time which takes the sea level as a reference plane and corresponds to the imaging point.
Optionally, the method further comprises: taking a plurality of speed values at intervals within a set speed range; calculating the travel time corresponding to each speed value by adopting the following formula:
wherein x is s Is the horizontal distance, x, from the shot point to the imaging point g The horizontal distance from the wave detection point to the imaging point is obtained, d is the depth of the sea bottom where the wave detection point is located, v is one of the plurality of speed values, and t is the one-way vertical time which takes the sea level as a reference plane and corresponds to the imaging point; determining the amplitude value of the multi-channel uplink wave seismic data participating in imaging of the imaging point according to the calculated travel time corresponding to each speed value; superposing the amplitude values of the multi-channel upgoing wave seismic data corresponding to each determined speed value to obtain a plurality of superposed amplitude values; and taking the speed value corresponding to the maximum value of the superposed amplitude in the plurality of superposed amplitude values as the root-mean-square speed which takes the sea level as the reference surface and corresponds to the imaging point.
Optionally, the migrating the plurality of uplink seismic data according to the calculated travel time of each of the plurality of uplink seismic data includes: determining an amplitude value of the upgoing wave seismic data corresponding to the travel time of each upgoing wave seismic data according to the corresponding relation and the travel time of each upgoing wave seismic data, wherein the corresponding relation is the corresponding relation between the signal waveform of the seismic data acquired by the acquisition equipment and time; calculating the average value of the amplitude values of the multi-channel up-going wave seismic data; the average value is placed at the position of the imaging point.
Optionally, the migrating the plurality of uplink seismic data according to the calculated travel time of each of the plurality of uplink seismic data includes: determining an amplitude value of the upgoing wave seismic data corresponding to the travel time of each upgoing wave seismic data according to the corresponding relation and the travel time of each upgoing wave seismic data, wherein the corresponding relation is the corresponding relation between the signal waveform of the seismic data acquired by the acquisition equipment and the time; and placing the determined amplitude value of each upgoing wave seismic data at the position of the imaging point.
In a second aspect, there is provided an apparatus for prestack time migration of upgoing seismic data, the apparatus comprising:
the acquisition module is used for acquiring seismic data acquired by acquisition equipment at the plurality of demodulation points, the plurality of demodulation points are positioned on the sea floor, each demodulation point is provided with one acquisition equipment, the acquisition equipment is used for acquiring seismic waves which are emitted by emission equipment at the shot point and reflected by a seabed stratum to obtain the seismic data, and the shot point is positioned on the sea level; the processing module is used for obtaining multi-channel uplink wave seismic data based on the seismic data; the calculation module is used for calculating the travel time of each upward wave seismic data from the shot point to the imaging point according to the root-mean-square velocity of the imaging point with the sea level as a reference surface; calculating the travel time of each uplink wave seismic data from the imaging point to the corresponding wave detection point according to the root-mean-square speed of the imaging point with the sea level as a reference surface; taking the sum of the calculated travel time of each upgoing wave seismic data from the shot point to the imaging point and the calculated travel time of each upgoing wave seismic data from the imaging point to the corresponding demodulator probe as the travel time of each upgoing wave seismic data; and the migration module is used for migrating the plurality of channels of upgoing wave seismic data according to the calculated travel time of each channel of upgoing wave seismic data.
Optionally, the calculation module is further configured to calculate a travel time of each of the upgoing wave seismic data from the shot point to the imaging point according to the following formula:
wherein, t S For the travel time of each upgoing wave seismic data from the shot point to the imaging point, t is the one-way vertical time with the sea level as the reference plane corresponding to the imaging point, x s And v is the horizontal distance from the shot point to the imaging point, and the root mean square velocity corresponding to the imaging point and taking the sea level as a reference surface.
Calculating the travel time of each upgoing wave seismic data from the imaging point to the corresponding demodulator probe according to the following formula:
wherein, t G For each travel time, x, of the upgoing seismic data from the imaging point to the corresponding detection point g The horizontal distance from a wave detection point corresponding to each upgoing wave seismic data to the imaging point, d is the seabed depth of the wave detection point, v is the root-mean-square velocity corresponding to the imaging point and taking the sea level as a reference surface, and t is the one-way vertical time corresponding to the imaging point and taking the sea level as a reference surface.
Optionally, the calculation module is further configured to take a plurality of speed values at intervals within a set speed range; calculating the travel time corresponding to each speed value by adopting the following formula:
wherein x is s Is the horizontal distance, x, from the shot point to the imaging point g The horizontal distance from the wave detection point to the imaging point is obtained, d is the depth of the sea bottom where the wave detection point is located, v is one of the plurality of speed values, and t is the one-way vertical time which takes the sea level as a reference plane and corresponds to the imaging point; determining a plurality of channels of upgoing waves which participate in imaging of the imaging points according to the calculated travel time corresponding to each speed valueAmplitude values of the data; superposing the amplitude values of the multi-channel up-going wave seismic data corresponding to each determined speed value to obtain a plurality of superposed amplitude values; and taking the speed value corresponding to the maximum value of the superposed amplitudes in the superposed amplitude values as the root-mean-square speed which corresponds to the imaging point and takes the sea level as a reference surface.
Optionally, the migration module is further configured to determine, according to a corresponding relationship and a travel time of each traveling wave seismic data, an amplitude value of the traveling wave seismic data corresponding to each traveling wave seismic data, where the corresponding relationship is a corresponding relationship between a signal waveform of the seismic data acquired by the acquisition device and time; calculating the average value of the amplitude values of the multi-channel up-going wave seismic data; and placing the average value at the imaging point position.
Optionally, the migration module is further configured to determine, according to a corresponding relationship and a travel time of each upward-traveling wave seismic data, an amplitude value of the upward-traveling wave seismic data corresponding to the travel time of each upward-traveling wave seismic data, where the corresponding relationship is a corresponding relationship between a signal waveform of the seismic data acquired by the acquisition device and time; and placing the determined amplitude value of each upgoing wave seismic data at the position of the imaging point.
In a third aspect, a computer device is provided, comprising: a processor; a memory for storing processor-executable instructions; wherein the processor is configured to perform the method of the first aspect.
In a fourth aspect, a computer-readable storage medium is provided, in which instructions, when executed by a processor of a computer device, enable the computer device to perform the method of the first aspect.
The technical scheme provided by the embodiment of the disclosure has the following beneficial effects:
in the disclosed embodiment, the travel time of the upgoing seismic data is the travel time from the shot point to the imaging point of the seafloor formation and the imaging point to the geophone point. When the upgoing wave seismic data travel from the imaging point to the demodulator probe, the root mean square speed corresponding to the imaging point and taking the sea floor as the datum plane is modified into the root mean square speed taking the sea level as the datum plane, namely when the upgoing wave seismic data travel is uniformly calculated by taking the sea level as the datum plane, the calculated upgoing wave seismic data travel from the imaging point to the demodulator probe can be calculated more accurately, the calculated upgoing wave seismic data travel can be further more accurate, and the migration precision of the upgoing wave seismic data is improved.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present disclosure, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present disclosure, and it is obvious for those skilled in the art to obtain other drawings based on the drawings without creative efforts.
FIG. 1 is a schematic view of a scenario for acquiring seismic data provided by an embodiment of the present disclosure;
FIG. 2 is a flow chart of a method for prestack time migration of upgoing seismic data according to an embodiment of the present disclosure;
FIG. 3 is a schematic diagram of the results of a prestack time migration of upgoing seismic data provided by an embodiment of the present disclosure;
FIG. 4 is a schematic diagram of results of another pre-stack time migration of upgoing seismic data provided by embodiments of the present disclosure;
fig. 5 is a schematic structural diagram of a pre-stack time migration apparatus for upgoing wave seismic data according to an embodiment of the present disclosure;
fig. 6 is a block diagram of a computer device according to an embodiment of the present disclosure.
Detailed Description
To make the objects, technical solutions and advantages of the present disclosure more apparent, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings.
To facilitate an understanding of the disclosed embodiments, a scenario in which seismic data is acquired in the disclosed embodiments is first described.
Fig. 1 is a schematic view of a scene for acquiring seismic data according to an embodiment of the present disclosure. Referring to fig. 1, a shot point S is provided on the sea level, and a plurality of demodulator probes R are provided on the sea floor. Fig. 1 illustrates an example of one shot point S and one demodulator probe R, and in practical application, one shot point S and a plurality of demodulator probes R are provided. The positional arrangement relationship between the shot S and the plurality of demodulator probes R is fixed, and the plurality of demodulator probes R move with the movement of the shot S.
The shot point S is provided with equipment for emitting seismic waves, and the equipment can be used for emitting the seismic waves. Each wave detection point R is provided with acquisition equipment which can be used for acquiring seismic waves reflected by the seabed stratum to obtain seismic data. The shot data transmitted by the transmitting equipment at the shot point S comprises a plurality of seismic waves, and the plurality of seismic waves are reflected at an imaging point M of the seabed stratum after being transmitted to the seabed stratum and then transmitted to the sea bottom surface to be collected by the collecting equipment at a plurality of wave detection points R. And the multi-shot data sent by the transmitting equipment at the shot point S are all collected by the collecting equipment at the plurality of wave detection points R. In some examples, a transmitting device at shot point S transmits one or more shots of data at a certain location to be collected by a plurality of acquisition devices at demodulator probes R, and then the transmitting device at shot point S and the acquisition devices at demodulator probes R move to the next location to transmit and collect data. For shot data sent by the launching equipment at the shot point S, the acquisition equipment at each wave detection point R acquires seismic waves reflected by the seabed stratum in the shot data to obtain the seismic data. And the seismic data corresponding to the same shot data and acquired by the acquisition equipment at the plurality of wave detection points R form a shot seismic data record.
In some embodiments, the collection device is an OBN (Ocean bottom nodes). The OBN is a four component detector arranged at the water bottom, and the four component detector consists of four component detectors. One of the component detectors is a pressure detector for recording the pressure component. The other three component detectors are velocity detectors for recording the three perpendicular velocity components.
Fig. 2 is a flowchart of a method for prestack time migration of upgoing seismic data according to an embodiment of the present disclosure, where the method may be executed by a computer device, such as a computer. Referring to fig. 2, the method includes:
in step 201, seismic data acquired by acquisition devices at a plurality of demodulation points is acquired.
The seismic data are acquired by acquisition equipment arranged at a plurality of detection points R. After the launching equipment at the shot point S sends out shot data, the acquisition equipment at each wave detection point R acquires a seismic wave of the shot data reflected by the seabed stratum to obtain a seismic data. The computer device may acquire seismic data acquired by a plurality of acquisition devices by communicating with the acquisition devices provided at the plurality of detection points R.
When the acquisition device is an OBN, the acquired seismic data includes a pressure component P, a velocity component X, a velocity component Y, and a velocity component Z, wherein the velocity component X and the velocity component Y are parallel to the sea level and the velocity component Z is perpendicular to the sea level.
In step 202, multi-channel up-wave seismic data is obtained based on the seismic data.
In the disclosed embodiment, the acquisition device at each geophone point R acquires multiple channels of seismic data, each channel of seismic data being from a different shot data from shot S. Each channel of seismic data acquired by the acquisition equipment at the wave detection point R comprises up-wave seismic data and down-wave seismic data. The propagation path of the uplink wave seismic data comprises a shot point to imaging point and an imaging point to geophone point, and the propagation path of the downlink wave seismic data comprises a shot point to imaging point, an imaging point to sea level and a sea level to geophone point. Namely, the reflected waves which are collected by the wave detection point and propagated from bottom to top are up-going wave seismic data, and the reflected waves which are collected by the wave detection point and propagated from top to bottom are down-going wave seismic data. In the embodiment of the present disclosure, only the upgoing wave seismic data need to be used, and therefore, the seismic data acquired by the acquisition device needs to be processed to obtain the upgoing wave seismic data.
Illustratively, processing the seismic data includes:
the first step is as follows: and performing denoising, deconvolution and amplitude matching processing on the pressure component P in the seismic data to obtain a processed pressure component P. And denoising, deconvolution and amplitude matching are carried out on the vertical velocity component Z in the three mutually perpendicular velocity components X, Y, Z in the seismic data to obtain the processed vertical velocity component Z.
The second step: and determining the upgoing wave seismic data according to the processed pressure component P and the processed vertical velocity component Z.
Illustratively, the pressure component P processed in the first step and the vertical velocity component Z processed in the first step are separated by using formula (1), so as to obtain the upgoing wave seismic data.
U＝(P+ρcZ)/2 (1)
In the formula (1), U represents the upgoing wave seismic data, P is the processed pressure component, Z is the processed vertical velocity component, ρ is the density of water, and c is the acoustic velocity.
In the embodiment of the present disclosure, the multi-channel up-going wave seismic data is the multi-channel up-going wave seismic data that participates in the same imaging point M and is within the offset aperture range of the imaging point M.
The offset aperture range refers to a range of distances from the imaging point M centered on the imaging point M. The coordinates of the shot point S are known, and the multi-channel upgoing wave seismic data refer to the multi-channel upgoing wave seismic data corresponding to the multi-shot data sent out by the shot point S in the migration aperture range.
The offset aperture range is an empirical value, illustratively set to the coordinates of the image point M as (Px, py), where Px-Dx < Px + Dx, py-Dy < Py + Dy, and Dx and Dy take values between 5000 and 6000 meters.
In step 203, the travel time of each up-going wave seismic data from the shot point to the imaging point is calculated according to the root-mean-square velocity of the imaging point with the sea level as a reference surface.
In some embodiments, the travel time of each up-going wave seismic data from the shot to the imaging point is calculated according to the following formula:
in the formula (2), t S When each path of upgoing wave seismic data travels from a shot point to an imaging point, t is the one-way vertical time corresponding to the imaging point and taking the sea level as a reference surface, and x s And v is the root mean square velocity corresponding to the imaging point and taking the sea level as a reference surface.
In step 204, the travel time of each up-going wave seismic data from the imaging point to the corresponding demodulator probe is calculated according to the root-mean-square velocity of the imaging point with the sea level as a reference surface.
In some embodiments, the travel time of each up-going seismic data from an imaging point to a corresponding demodulator point is calculated according to the following formula:
in the formula (3), t G For each travel time, x, from imaging point to corresponding wave detection point of the up-wave seismic data g The horizontal distance from a wave detection point corresponding to each up-going wave seismic data to an imaging point, d is the depth of the sea floor where the wave detection point is located, v is the root-mean-square velocity which takes the sea level as a reference plane and corresponds to the imaging point, and t is the one-way vertical time which takes the sea level as the reference plane and corresponds to the imaging point.
Since the coordinates of shot S, imaging point M, and geophone R are known, x s Can be obtained from the coordinates of the shot point S and the coordinates of the imaging point M, x g Can be obtained from the coordinates of the imaging point M and the coordinates of the demodulator probe R. d can be measured by a seismic detector.
v is obtained by velocity analysis, which in some embodiments is:
in the first step, for a certain imaging point M, a plurality of velocity values are taken at intervals within a set velocity range.
The speed range is an empirical value, and is illustratively set to 3000km/s to 5000km/s with the speed interval set to 50km/s.
Secondly, calculating the travel time corresponding to each speed value by adopting the following formula:
in the formula (4), x s Is the horizontal distance, x, from the shot point to the imaging point g The horizontal distance from the demodulator probe to the imaging point is defined, d is the depth of the sea bottom where the demodulator probe is located, v is one of the plurality of velocity values, and t is the one-way vertical time corresponding to the imaging point and taking the sea level as a reference surface.
And thirdly, determining the amplitude value of the multi-channel up-going wave seismic data participating in imaging of the imaging point according to the calculated travel time corresponding to each velocity value.
And fourthly, superposing the amplitude values of the multi-channel upgoing wave seismic data corresponding to each determined velocity value to obtain a plurality of superposed amplitude values.
And fifthly, taking the velocity value corresponding to the maximum value of the superposed amplitude in the superposed amplitude values as the root mean square velocity value corresponding to the imaging point and taking the sea level as the reference surface.
It should be noted that, in the embodiment of the present disclosure, each geological layer in the submarine geological profile has a plurality of imaging points, only a part of the imaging points are subjected to velocity analysis to obtain root mean square velocity values corresponding to the part of the imaging points with the sea level as a reference surface, and root mean square velocity values corresponding to other imaging points with the sea level as a reference surface may be obtained by an inverse distance interpolation method. For example, the submarine geological profile includes 100 geological layers, each geological layer is provided with 10 imaging points at intervals, and only the root mean square velocity values with the sea level as the reference surface at the 1 st, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100 st geological layers 1, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100 th imaging points can be calculated according to the velocity analysis method. And calculating root mean square speed difference values of the 1 st imaging point and the 10 th imaging point by taking the sea level as a reference surface according to the root mean square speed difference values and calculating root mean square speed values of the sea level as the reference surface corresponding to the imaging points between the 1 st imaging point and the 10 th imaging point in the first geological layer by adopting an inverse distance interpolation method.
In step 205, the sum of the calculated travel time of each upward wave seismic data from the shot point to the imaging point and the calculated travel time from the imaging point to the corresponding demodulator probe is taken as the travel time of each upward wave seismic data.
In the embodiment of the disclosure, when the upgoing wave seismic data travels from the imaging point to the wave detection point, the root-mean-square velocity corresponding to the imaging point and taking the sea bottom surface as the reference surface is modified into the root-mean-square velocity taking the sea level as the reference surface, so that the upgoing wave seismic data travel from the imaging point to the wave detection point calculated according to the trigonometric row formula can be calculated more accurately.
In step 206, the multi-channel up-going wave seismic data is migrated according to the calculated travel time of each channel up-going wave seismic data.
In some embodiments, migrating the multi-channel up-going seismic data includes:
and step one, determining the amplitude value of the uplink wave seismic data corresponding to the travel time of each uplink wave seismic data according to the corresponding relation and the travel time of each uplink wave seismic data.
The corresponding relation is the corresponding relation between the signal waveform of the seismic data acquired by the acquisition equipment and the time.
Illustratively, the acquisition device at each demodulation point records therein a correspondence of a signal waveform of the acquired seismic data with time. The data acquired by the computer device from each acquisition device comprises seismic data acquired by the acquisition device and the corresponding relation between the signal waveform of the seismic data and time.
According to the travel time of the uplink wave seismic data and the corresponding relation between the signal waveform of the seismic data acquired by the corresponding acquisition equipment and the time, the accurate amplitude value of the uplink wave seismic data can be acquired, and further the result of migration according to the accurate amplitude value of the uplink wave seismic data can be more accurate.
And secondly, calculating the average value of the amplitude values of the multi-channel up-going wave seismic data.
And thirdly, placing the average value at the position of the imaging point M.
And placing the calculated amplitude average value of the multi-channel upgoing wave seismic data to the position of an imaging point M, and finishing the migration of the multi-channel upgoing wave seismic data.
The amplitude values of the seismic data represent the energy of the seismic waves. The physical meaning of migration is to return the collected reflected seismic waves to the location of the reflection point where they originated, causing them to be imaged.
Because the amplitude value of the multi-channel uplink wave seismic data is directly placed at the imaging point M, the amplitude value at the imaging point M is larger, and the imaging quality at the imaging point M is imaged by the larger amplitude value. Therefore, the average amplitude value of the multi-channel up-going wave seismic data is put to an imaging point, the amplitude value of the multi-channel up-going wave seismic data can be balanced, imaging at the imaging point M cannot be influenced due to overlarge sum of the amplitude values of the multi-channel up-going wave seismic data, and imaging quality can be improved.
In other embodiments, migrating the multi-channel up-traveling wave seismic data includes: determining the amplitude value of the uplink wave seismic data corresponding to the travel time of each uplink wave seismic data according to the corresponding relation and the travel time of each uplink wave seismic data, wherein the corresponding relation is the corresponding relation between the signal waveform of the seismic data acquired by the acquisition equipment and the time; and placing the determined amplitude value of the up-going wave seismic data of each channel at the position of the imaging point. Under the premise of not influencing the imaging quality of the imaging point, the amplitude of the multi-channel upgoing wave seismic data can be directly placed at the imaging point M.
Fig. 3 is a geological profile obtained by performing prestack time migration on the uplink seismic data by using a method of the related art, and fig. 4 is a geological profile obtained by performing prestack time migration on the uplink seismic data by using a method provided by an embodiment of the present disclosure. It has been found by comparing fig. 3 and 4 that each stratigraphic line of the geological profile of fig. 4 is smoother than each stratigraphic line of the geological profile of fig. 3, e.g., the stratigraphic lines circled by the black boxes in fig. 4 are smoother than the horizon lines circled by the black boxes in fig. 3. It is demonstrated that the imaging accuracy is better than the related art according to the method of the embodiment of the present disclosure.
In the disclosed embodiment, the travel time of the upgoing seismic data is the travel time from the shot point to the imaging point of the seafloor formation and the imaging point to the geophone point. When the upgoing wave seismic data travel from the imaging point to the demodulator probe, the root-mean-square speed which takes the sea bottom surface as the reference surface and corresponds to the imaging point is modified into the root-mean-square speed which takes the sea level as the reference surface, namely when the upgoing wave seismic data travel is calculated by taking the sea level as the reference surface, the calculated upgoing wave seismic data travel from the imaging point to the demodulator probe can be calculated more accurately, the calculated upgoing wave seismic data travel can be more accurate, and the migration precision of the upgoing wave seismic data is improved.
Fig. 5 is a block diagram of a structure of a pre-stack time migration apparatus 500 for upgoing wave seismic data according to an embodiment of the present disclosure. As shown in fig. 5, the apparatus includes: an acquisition module 501, a processing module 502, a calculation module 503, and an offset module 504.
An obtaining module 501, configured to obtain seismic data collected by collection equipment at multiple geophone points, where the multiple geophone points are located on a sea floor, and each geophone point is provided with one collection equipment, where the collection equipment is configured to collect seismic waves emitted by emission equipment at a shot point and reflected by a seabed stratum, so as to obtain the seismic data, and the shot point is located on the sea floor; a processing module 502, configured to obtain multichannel uplink wave seismic data based on the seismic data; a calculating module 503, configured to calculate a travel time of each of the upgoing wave seismic data from the shot point to the imaging point according to a root-mean-square velocity of the imaging point with sea level as a reference plane; calculating the travel time of each uplink wave seismic data from the imaging point to the corresponding wave detection point according to the root-mean-square speed of the imaging point with the sea level as a reference surface; and taking the sum of the calculated travel time of each upgoing wave seismic data from the shot point to the imaging point and the calculated travel time from the imaging point to the corresponding demodulator probe as the travel time of each upgoing wave seismic data. And the migration module 504 is configured to perform migration on the multiple pieces of upgoing wave seismic data according to the calculated travel time of each piece of upgoing wave seismic data.
Optionally, the calculation module 503 is further configured to calculate a travel time of each of the upgoing seismic data from the shot to the imaging point according to the following formula:
wherein, t S For the travel time of each upgoing wave seismic data from the shot point to the imaging point, t is the one-way vertical time with the sea level as the reference plane corresponding to the imaging point, x s And v is the horizontal distance from the shot point to the imaging point, and the root mean square velocity corresponding to the imaging point and taking the sea level as a reference surface.
Calculating the travel time of each upgoing wave seismic data from the imaging point to the corresponding demodulator probe according to the following formula:
wherein, t G For each travel time, x, of the upgoing seismic data from the imaging point to the corresponding geophone point g The horizontal distance from a wave detection point corresponding to each upgoing wave seismic data to the imaging point, d is the depth of the sea bottom where the wave detection point is located, v is the root-mean-square velocity which takes the sea level as a reference plane and corresponds to the imaging point, and t is the one-way vertical time which takes the sea level as the reference plane and corresponds to the imaging point.
Optionally, the calculating module 503 is further configured to take a plurality of speed values at intervals within a set speed range; calculating the travel time corresponding to each speed value by adopting the following formula:
wherein x is s Is the horizontal distance, x, from the shot point to the imaging point g The horizontal distance from the wave detection point to the imaging point is obtained, d is the depth of the sea bottom where the wave detection point is located, v is one of the plurality of speed values, and t is the one-way vertical time which takes the sea level as a reference plane and corresponds to the imaging point; determining the amplitude value of the multi-channel up-wave seismic data participating in imaging of the imaging point according to the calculated travel time corresponding to each speed value; superposing the amplitude values of the multi-channel up-going wave seismic data corresponding to each determined speed value to obtain a plurality of superposed amplitude values; and taking the speed value corresponding to the maximum value of the superposed amplitude in the superposed amplitude values as the root-mean-square speed which takes the sea level as the reference surface and corresponds to the imaging point.
Optionally, the migration module 504 is further configured to determine an amplitude value of the uplink wave seismic data corresponding to each traveling time of the uplink wave seismic data according to a corresponding relationship and the traveling time of each uplink wave seismic data, where the corresponding relationship is a corresponding relationship between a signal waveform of the seismic data acquired by the acquisition device and time; calculating the average value of the amplitude values of the multi-channel up-going wave seismic data; and placing the average value at the imaging point position.
Optionally, the migration module 504 is further configured to determine an amplitude value of the uplink wave seismic data corresponding to each traveling time of the uplink wave seismic data according to a corresponding relationship and the traveling time of each uplink wave seismic data, where the corresponding relationship is a corresponding relationship between a signal waveform of the seismic data acquired by the acquisition device and time; and placing the determined amplitude value of each upgoing wave seismic data at the position of the imaging point.
It should be noted that: the prestack time migration apparatus 500 for the uplink seismic data provided in the foregoing embodiment is only illustrated by the above-mentioned division of each functional module when performing prestack time migration on the uplink seismic data, and in practical applications, the above-mentioned function allocation may be completed by different functional modules according to needs, that is, the internal structure of the device is divided into different functional modules, so as to complete all or part of the above-described functions. In addition, the prestack time migration apparatus 500 for uplink seismic data provided in the foregoing embodiment and the prestack time migration method for uplink seismic data belong to the same concept, and specific implementation processes thereof are detailed in the method embodiment and are not described herein again.
Fig. 6 is a block diagram of a computer device provided in an embodiment of the present disclosure. As shown in fig. 6, the apparatus includes: a processor 601 and a memory 602.
The processor 601 may include one or more processing cores, such as a 4-core processor, an 8-core processor, and so on. The processor 601 may be implemented in at least one hardware form of a DSP (Digital Signal Processing), an FPGA (Field-Programmable Gate Array), and a PLA (Programmable Logic Array). The processor 601 may also include a main processor and a coprocessor, where the main processor is a processor for Processing data in an awake state, and is also called a Central Processing Unit (CPU); a coprocessor is a low power processor for processing data in a standby state. In some embodiments, the processor 601 may be integrated with a GPU (Graphics Processing Unit), which is responsible for rendering and drawing the content required to be displayed on the display screen. In some embodiments, processor 601 may also include an AI (Artificial Intelligence) processor for processing computational operations related to machine learning.
The memory 602 may include one or more computer-readable storage media, which may be non-transitory. The memory 602 may also include high-speed random access memory, as well as non-volatile memory, such as one or more magnetic disk storage devices, flash memory storage devices. In some embodiments, a non-transitory computer readable storage medium in memory 602 is used to store at least one instruction for execution by processor 601 to implement the method for prestack time migration of upgoing seismic data provided in embodiments of the present application.
Those skilled in the art will appreciate that the architecture shown in FIG. 6 is not intended to be limiting of computer devices, and may include more or fewer components than those shown, or some components may be combined, or a different arrangement of components may be used.
An embodiment of the present invention further provides a non-transitory computer-readable storage medium, where instructions in the storage medium, when executed by a processor of a computer device, enable the computer device to execute the pre-stack time migration method for uplink seismic data provided in an embodiment of the present application.
A computer program product containing instructions which, when run on a computer, cause the computer to perform the method for prestack time migration of upgoing seismic data as provided by embodiments of the present application.
The above description is intended to be exemplary only and not to limit the present disclosure, and any modification, equivalent replacement, or improvement made without departing from the spirit and scope of the present disclosure is to be considered as the same as the present disclosure.
Claims (10)
1. A method of prestack time migration of upgoing seismic data, the method comprising:
acquiring seismic data acquired by acquisition equipment at a plurality of demodulation points, wherein the plurality of demodulation points are positioned on the sea bottom surface, each demodulation point is provided with one acquisition equipment, the acquisition equipment is used for acquiring seismic waves which are emitted by emission equipment at shot points and reflected by a seabed stratum to obtain the seismic data, and the shot points are positioned on the sea level;
obtaining multi-channel uplink wave seismic data based on the seismic data;
calculating the travel time of each upgoing wave seismic data from the shot point to the imaging point according to the root-mean-square speed of the imaging point with the sea level as a reference surface;
calculating the travel time of each uplink wave seismic data from the imaging point to the corresponding wave detection point according to the root-mean-square speed of the imaging point with the sea level as a reference surface;
taking the sum of the calculated travel time of each upgoing wave seismic data from the shot point to the imaging point and the calculated travel time of each upgoing wave seismic data from the imaging point to the corresponding demodulator probe as the travel time of each upgoing wave seismic data;
and shifting the plurality of channels of upgoing wave seismic data according to the calculated travel time of each channel of upgoing wave seismic data.
2. The method of claim 1, wherein calculating the travel time of each of the upgoing seismic data from the shot point to the imaging point according to a root-mean-square velocity at the imaging point with respect to a sea level comprises: calculating travel time of each said upgoing seismic data from said shot to said imaging point according to the following formula:
wherein, t S For the travel time of each upgoing wave seismic data from the shot point to the imaging point, t is the one-way vertical time with the sea level as the reference plane corresponding to the imaging point, x s The horizontal distance from the shot point to the imaging point is defined, and v is the root mean square velocity which takes the sea level as a reference plane and corresponds to the imaging point;
the calculating the travel time of each uplink wave seismic data from the imaging point to the corresponding wave detection point according to the root-mean-square velocity of the imaging point with the sea level as a reference surface comprises the following steps: calculating the travel time of each upgoing wave seismic data from the imaging point to the corresponding demodulator probe according to the following formula:
wherein, t G For each travel time, x, of the upgoing seismic data from the imaging point to the corresponding geophone point g The horizontal distance from a wave detection point corresponding to each up-going wave seismic data to the imaging point, and d is the distanceAnd v is the root-mean-square velocity which takes the sea level as a reference plane and corresponds to the imaging point, and t is the one-way vertical time which takes the sea level as the reference plane and corresponds to the imaging point.
3. The method of claim 2, further comprising:
taking a plurality of speed values at intervals within a set speed range;
calculating the travel time corresponding to each speed value by adopting the following formula:
wherein x is s Is the horizontal distance, x, from the shot point to the imaging point g The horizontal distance from the wave detection point to the imaging point is obtained, d is the depth of the sea bottom where the wave detection point is located, v is one of the plurality of speed values, and t is the one-way vertical time which takes the sea level as a reference plane and corresponds to the imaging point;
determining the amplitude value of the multi-channel uplink wave seismic data participating in imaging of the imaging point according to the calculated travel time corresponding to each speed value;
superposing the amplitude values of the multi-channel up-going wave seismic data corresponding to each determined speed value to obtain a plurality of superposed amplitude values;
and taking the speed value corresponding to the maximum value of the superposed amplitudes in the superposed amplitude values as the root-mean-square speed which corresponds to the imaging point and takes the sea level as a reference surface.
4. The method of claim 1, wherein the migrating the plurality of up-going seismic data based on the calculated travel time of each of the up-going seismic data comprises:
determining an amplitude value of the upgoing wave seismic data corresponding to the travel time of each upgoing wave seismic data according to the corresponding relation and the travel time of each upgoing wave seismic data, wherein the corresponding relation is the corresponding relation between the signal waveform of the seismic data acquired by the acquisition equipment and the time;
calculating the average value of the amplitude values of the multi-channel up-going wave seismic data;
the average value is placed at the position of the imaging point.
5. The method of claim 1, wherein the migrating the plurality of up-going seismic data based on the calculated travel time of each of the up-going seismic data comprises:
determining an amplitude value of the upgoing wave seismic data corresponding to the travel time of each upgoing wave seismic data according to the corresponding relation and the travel time of each upgoing wave seismic data, wherein the corresponding relation is the corresponding relation between the signal waveform of the seismic data acquired by the acquisition equipment and the time;
and placing the determined amplitude value of each upgoing wave seismic data at the position of the imaging point.
6. An apparatus for prestack time migration of up-wave seismic data, the apparatus comprising:
the acquisition module is used for acquiring seismic data acquired by acquisition equipment at the plurality of demodulation points, the plurality of demodulation points are positioned on the sea floor, each demodulation point is provided with one acquisition equipment, the acquisition equipment is used for acquiring seismic waves which are emitted by emission equipment at the shot point and reflected by a seabed stratum to obtain the seismic data, and the shot point is positioned on the sea level;
the processing module is used for obtaining multi-channel uplink wave seismic data based on the seismic data;
the calculation module is used for calculating the travel time of each piece of upgoing wave seismic data from the shot point to the imaging point according to the root-mean-square velocity of the imaging point with the sea level as a reference surface; calculating the travel time of each uplink wave seismic data from the imaging point to the corresponding wave detection point according to the root-mean-square speed of the imaging point on the sea level as a reference surface; taking the sum of the calculated travel time of each upgoing wave seismic data from the shot point to the imaging point and the calculated travel time of each upgoing wave seismic data from the imaging point to the corresponding demodulator probe as the travel time of each upgoing wave seismic data;
and the migration module is used for migrating the plurality of channels of upgoing wave seismic data according to the calculated travel time of each channel of upgoing wave seismic data.
7. The apparatus of claim 6, wherein the calculation module is further configured to calculate a travel time of each of the upgoing seismic data from the shot to the imaging point according to the following formula:
wherein, t S For the travel time of each upgoing wave seismic data from the shot point to the imaging point, t is the one-way vertical time with the sea level as the reference plane corresponding to the imaging point, x s The horizontal distance from the shot point to the imaging point is defined, and v is the root mean square velocity which takes the sea level as a reference plane and corresponds to the imaging point;
calculating travel time of each upgoing wave seismic data from the imaging point to the corresponding wave detection point according to the following formula:
wherein, t G For each travel time, x, of the upgoing seismic data from the imaging point to the corresponding geophone point g The horizontal distance from a wave detection point corresponding to each upgoing wave seismic data to the imaging point, d is the seabed depth of the wave detection point, v is the root-mean-square velocity corresponding to the imaging point and taking the sea level as a reference surface, and t is the one-way vertical velocity corresponding to the imaging point and taking the sea level as a reference surfaceTime.
8. The apparatus of claim 6, wherein the migration module is further configured to determine an amplitude value of the upgoing wave seismic data corresponding to the travel time of each of the upgoing wave seismic data according to a corresponding relationship and the travel time of each of the upgoing wave seismic data, where the corresponding relationship is a corresponding relationship between a signal waveform of the seismic data acquired by the acquisition device and time; calculating the average value of the amplitude values of the multi-channel upgoing wave seismic data; the average value is placed at the position of the imaging point.
9. A computer device, comprising:
a processor;
a memory for storing processor-executable instructions;
wherein the processor is configured to perform the method of any one of claims 1 to 5.
10. A computer-readable storage medium, wherein instructions in the computer-readable storage medium, when executed by a processor of a computer device, enable the computer device to perform the method of any of claims 1 to 5.
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