CN117930360B - Method for correcting fault shadows in post-stack seismic data - Google Patents
Method for correcting fault shadows in post-stack seismic data Download PDFInfo
- Publication number
- CN117930360B CN117930360B CN202410329354.4A CN202410329354A CN117930360B CN 117930360 B CN117930360 B CN 117930360B CN 202410329354 A CN202410329354 A CN 202410329354A CN 117930360 B CN117930360 B CN 117930360B
- Authority
- CN
- China
- Prior art keywords
- time domain
- horizon
- interpretation
- fault
- seismic
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
- 238000000034 method Methods 0.000 title claims abstract description 22
- 238000010276 construction Methods 0.000 claims abstract description 13
- 238000011160 research Methods 0.000 claims abstract description 11
- 238000004364 calculation method Methods 0.000 claims abstract description 9
- 238000006243 chemical reaction Methods 0.000 claims abstract description 5
- 230000002159 abnormal effect Effects 0.000 claims description 15
- 230000015572 biosynthetic process Effects 0.000 claims description 7
- 238000005553 drilling Methods 0.000 claims description 5
- 238000004519 manufacturing process Methods 0.000 claims description 2
- 238000013517 stratification Methods 0.000 claims description 2
- 238000012937 correction Methods 0.000 description 12
- 241000256602 Isoptera Species 0.000 description 2
- 238000011161 development Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 239000007789 gas Substances 0.000 description 2
- 238000003384 imaging method Methods 0.000 description 2
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 2
- 239000011324 bead Substances 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000001427 coherent effect Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 238000011156 evaluation Methods 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 238000013508 migration Methods 0.000 description 1
- 230000005012 migration Effects 0.000 description 1
- 239000003345 natural gas Substances 0.000 description 1
- 239000003209 petroleum derivative Substances 0.000 description 1
- 230000002265 prevention Effects 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 239000011435 rock Substances 0.000 description 1
- 238000003860 storage Methods 0.000 description 1
Landscapes
- Geophysics And Detection Of Objects (AREA)
Abstract
The invention relates to a method for correcting fault shadows in post-stack seismic data, comprising: making and calibrating synthetic seismic records of all wells in a research area, and performing horizon interpretation; determining the influence range of a fault shadow zone; establishing a time domain construction distortion amount calculation formula, and solving the time domain construction distortion amount; adjusting the interpretation horizon of the fault shadow zone according to the time domain construction distortion to obtain a corrected time domain interpretation horizon; modifying the synthetic record calibration position of the fault shadow zone well according to the corrected time domain interpretation horizon, and establishing a reasonable space velocity field; and performing time-depth conversion on the corrected time domain interpretation horizon by using the space velocity field to obtain a real depth domain horizon. The invention establishes a distortion amount solving formula, directly corrects the time domain interpretation result, and has simple operation and high accuracy.
Description
Technical Field
The invention relates to the field of geophysical prospecting of petroleum and natural gas, in particular to a method for correcting fault shadows in post-stack seismic data, which is applied to guiding marine prospecting and development.
Background
The seismic data is a data body formed by the fact that seismic waves excited by the earth surface propagate downwards, are reflected to the earth surface after encountering an underground geologic body interface and are recorded by a receiver, and the measurement unit is double-pass reflection time. In general, the stratum speed is relatively uniform, the time domain of the geologic body is approximately equivalent to the structural form of the depth domain, and the interpretation result of the time domain seismic data can reflect the structural form of the depth domain. The seismic data can be used for revealing the spread information of geologic bodies such as underground stratum, faults and the like through interpretation work. If a velocity anomaly layer (such as thick mudstone, magma rock and the like) exists in the stratum and a large break fault is generated by breaking the stratum, the thickness of the velocity anomaly layer is suddenly changed, and the average velocity of the stratum is suddenly changed. Due to the variation of the average velocity, the time for the surface-excited seismic waves to reach a certain depth of formation will also vary during seismic data acquisition. At this time, the geologic body morphology (time domain morphology) revealed by the seismic data will not be identical to the true morphology (depth domain morphology). This phenomenon is caused by the fault fracture velocity anomaly layer, and is characterized in the seismic data by the occurrence of "pull-up and pull-down" of the same phase axis of the seismic in the triangular area below the fault, and the phenomenon is called "fault shadow".
Sun Weizhao et al in forward modeling, recognition and correction of tomosynthesis: the formation principle of 'fault shadow' is researched by taking Nile Termit basin as an example, and the 'fault shadow' phenomenon is indicated to be commonly existed in various oil-gas-containing basins, and is easily interpreted as a minor fault associated with a main fault in the seismic interpretation process or as a anticline structure to deploy drilling, so that the accuracy of trap evaluation and well position deployment is seriously influenced. In recent years, a large amount of oil and gas resources are found in the ocean field in China, but because of high ocean exploration and development risks, the accuracy requirement on interpretation results of seismic data is higher, and accurate identification is particularly important to correct the fault shadow phenomenon.
The former has also proposed various methods of prevention and correction for the "tomosynthesis" phenomenon. The invention patent CN202110745589.8 discloses a method, a device, equipment and a storage medium for acquiring CRP gather in a fault shadow area, which are used for establishing a fine pre-stack migration velocity model for seismic data with relatively stable transverse consistency of signal to noise ratio and obtaining a data body with improved consistency. "bead-depression fault shadow zone imaging technology and practice" of the Zhujiang oral basin of white navy et al is disclosed in 2022, which indicates that the fault control and horizon constraint-based chromatographic speed modeling can improve the fault shadow zone structure imaging quality. "forward modeling, recognition and correction of fault shadows" by Sun Weizhao et al, published in geophysical progress 2022: taking Nile Termit basin as an example ", the time domain structure abnormal variable scattered point data obtained through fitting is pointed out, and further the travel time quantitative compensation correction technology for obtaining the grid correction value through interpolation can correct the time domain earthquake cophase axes.
The processing effect on pre-stack seismic data may be undesirable due to the constraints of the actual regional acquisition conditions. Resulting in "fault shadowing" phenomena in post-stack seismic data in many areas. The correction method of the fault shadow phenomenon in post-stack seismic data by the former is relatively complicated, and a theoretical formula capable of accurately calculating the correction amount is not provided. A method for correcting fault shadows in post-stack seismic data, which is high in accuracy and operability, needs to be proposed.
Disclosure of Invention
The invention aims to provide a method for correcting fault shadows in post-stack seismic data, which is used for solving the problems that the correction method for the fault shadows in post-stack seismic data in the prior art is relatively complicated and has insufficient accuracy.
The technical scheme adopted for solving the technical problems is as follows: the method for correcting fault shadows in post-stack seismic data comprises the steps of:
Step one, performing synthetic seismic record manufacturing and calibration on all wells in a research area, and performing horizon interpretation;
Step two, determining the influence range of a fault shadow area;
Step three, a time domain construction distortion calculation formula is established, and the time domain construction distortion is calculated;
a time domain construction distortion calculation formula:
Wherein: Δt is the time domain distortion, which is the double-pass time, ms; d is the thickness of the speed anomaly layer, m; v 1 is the speed of the abnormal speed layer, m/s; v 2 is the velocity of the normal formation adjacent to the abnormal layer, m/s; d is obtained from seismic interpretation in combination with well data: if the abnormal layer is completely broken, the thickness of the broken layer is the thickness of the stratum; if the abnormal layer is partially broken, the breaking thickness is a vertical breaking distance; v 1 and v 2 are obtained from the borehole acoustic time difference curve;
step four, adjusting the interpretation horizon of the fault shadow zone according to the time domain construction distortion, and obtaining a corrected time domain interpretation horizon;
Step five, modifying the synthetic record calibration position of the fault shadow zone well according to the corrected time domain interpretation horizon, and establishing a reasonable space velocity field;
And step six, performing time depth conversion on the corrected time domain interpretation horizon by using the space velocity field to obtain a real depth domain horizon.
The first step in the scheme is specifically as follows:
Making synthetic seismic records of all wells in a research area by using an acoustic time difference curve and a density curve, matching and calibrating according to the similarity of the synthetic seismic records and the actual seismic records beside the wells, establishing a time-depth relationship of each well, and determining the corresponding positions of geological layers on a time domain seismic section; and performing seismic data horizon interpretation on the whole area according to the calibrated position of the well stratification on the seismic section.
The step four in the scheme is specifically as follows:
If the fault shadow area earthquake event is pulled up, the interpretation horizon is moved downwards according to the magnitude of the distortion; if the fault shadow area earthquake event is pulled down on the same phase axis, the interpretation horizon is moved upwards according to the magnitude of the distortion, so that the horizon trend of the fault shadow area is consistent with that of the normal stratum, the interpretation of the full research area is conducted, and the corrected time domain interpretation horizon is obtained.
The fifth step in the scheme is as follows:
And modifying the calibrated position of the drilling synthetic record in the shadow region according to the corrected time domain interpretation horizon, so that the well layering of the synthetic seismic record is matched with the corrected interpretation horizon, the average stratum speed consistent with the normal stratum is obtained, and a space velocity field is established by taking the interpretation horizon as a constraint.
Advantageous effects
1. The invention provides a distortion amount calculation formula, directly corrects the time domain interpretation result, has simple operation and high accuracy, and can be applied to various complex geological conditions of sea and land basin.
2. The method for correcting the fault shadow phenomenon in the post-stack seismic data is simple, and a calculation formula capable of accurately calculating the correction amount is provided, so that the method is high in accuracy and high in operability, is used for correcting the fault shadow phenomenon in the post-stack seismic data, and is beneficial to obtaining the real structural form of the stratum under the fault.
Drawings
FIG. 1 is a well A synthetic record calibration chart;
FIG. 2 is a top and bottom interpretation horizon cross-section of the destination layer prior to correction;
FIG. 3 is a graph of example zone "tomosynthesis" coverage;
FIG. 4 is a top and bottom interpretation horizon profile of the corrected destination layer;
FIG. 5 is a plot of synthetic seismic recordings of wells in the shadow zone at a modified calibration position;
FIG. 6 is a diagram of establishing a reasonable velocity field;
FIG. 7 is a depth domain horizon profile obtained from time-depth conversion.
Detailed Description
The invention is further described below with reference to the accompanying drawings:
the method for correcting fault shadows in post-stack seismic data comprises the steps of:
Step one, as shown in fig. 1, making and calibrating synthetic seismic records of all wells in an example research area, wherein the making of the synthetic seismic records uses a sound wave time difference curve and a density curve, and matching operation is carried out through the synthetic seismic records and the real seismic records beside the wells to obtain the time-depth relation of each well, and the positions of well layering on a time domain seismic section are clarified, so that the paraxial horizon interpretation of the seismic data is carried out (fig. 2).
And step two, extracting coherence attribute from the seismic data to obtain a coherence bedding slice. And determining the influence range of the fault shadow zone according to the position of the pseudo fault on the plane coherent slice, the 'pull-up and pull-down' range of the seismic event below the fault on the section and the position of the dislocation or distortion of the seismic event. As shown in fig. 3, the left graph is a slice along the layer, the distribution of faults is visible on the slice, the right graph is a seismic reflection section, the triangle below the fault has the characteristic of "pull-up", and the right boundary of the triangle has the characteristic of dislocation of the same phase axis, so that the range of "fault shadows" is identified.
Step three, calculating the time domain construction distortion; according to the formation mechanism of 'fault shadows', the in-phase axis distortion is mainly caused by the fact that an overlying abnormal speed layer is broken or even completely lost, so that the speed of a seismic wave is suddenly changed in the propagation process, and the time required for reaching a target layer is also suddenly changed. And constructing an abnormal quantity calculation formula in the time domain:
Wherein: Δt is the time domain distortion, which is the double-pass time, ms; d is the thickness of the speed anomaly layer, m; v 1 is the speed of the abnormal speed layer, m/s; v 2 is the velocity of the normal formation adjacent to the abnormal layer, m/s.
Wherein the loss thickness (d) of the velocity anomaly layer can be obtained from seismic interpretation in combination with well data: if the abnormal layer is completely broken, the broken thickness is the stratum thickness; if the abnormal layer is partially broken, the broken thickness is the vertical break distance. Formation velocities (v 1 and v 2) are determined from the borehole sonic moveout curve.
And calculating the time domain distortion by using the formula according to the actual research area condition. The speed v 1 of the low-speed layer in the example research area is 2700m/s, the speed v 2 of the low-speed layer adjacent to the normal stratum is 3030m/s, and the low-speed layer is not completely broken, so that the breaking thickness d is the fault breaking distance, 50m is taken, and the data are substituted into a formula to obtain the deformation amount of 4.03ms.
Step four, adjusting the interpretation horizon of the fault shadow zone according to the time domain construction distortion, and obtaining a corrected time domain interpretation horizon: if the fault shadow area earthquake event is pulled up, the interpretation horizon is moved downwards according to the magnitude of the distortion; if the fault shadow area earthquake event is pulled down on the same phase axis, the interpretation horizon is moved upwards according to the magnitude of the distortion, so that the horizon trend of the fault shadow area is consistent with that of the normal stratum, the interpretation of the full research area is conducted, and the corrected time domain interpretation horizon is obtained.
Comparing FIG. 2 to the pre-correction horizon interpretation, it can be seen that the shadow zone seismic event has a "pull-up" feature. On this basis, the interpretation horizon of the shadow zone is shifted down by 4.03ms, so that the horizon trend of the fault shadow zone is consistent with that of the normal stratum, as shown in fig. 4. And carrying out full-area interpretation so as to obtain corrected time domain interpretation horizon.
Step five, modifying the synthetic record calibration position of the fault shadow zone well according to the corrected time domain interpretation horizon, and establishing a reasonable space velocity field, wherein the method specifically comprises the following steps: and modifying the calibrated position of the drilling synthetic record in the shadow region according to the corrected time domain interpretation horizon, so that the well layering of the synthetic seismic record is matched with the corrected interpretation horizon, the average stratum speed consistent with the normal stratum is obtained, and a space velocity field is established by taking the interpretation horizon as a constraint.
As shown in fig. 5, according to the correction amount obtained by calculation, the calibrated position of the well drilling synthetic seismic record in the shadow area is modified, so that the well layering of the synthetic seismic record is matched with the corrected interpretation horizon, the average stratum speed consistent with the normal stratum is obtained, the interpretation horizon is taken as a constraint, and a space velocity field is established by using a well velocity interpolation method. FIG. 6 is an adjusted velocity profile, showing that the velocities of the A-well within the shadow zone and the B-well outside the shadow zone are substantially the same.
And step six, performing time depth conversion on the corrected time domain interpretation horizon by using the velocity field to obtain a real depth domain horizon. Fig. 7 is a cross-sectional view of the depth domain finally obtained, from which it can be seen that the horizon of the depth domain in the "tomogram" region is smooth, and its structural trend is consistent with that of the normal region, conforming to the true structural morphology.
Claims (1)
1. A method for correcting fault shadows in post-stack seismic data, comprising the steps of:
Step one, performing synthetic seismic record manufacturing and calibration on all wells in a research area, and performing horizon interpretation; the method comprises the following steps:
making synthetic seismic records of all wells in a research area by using an acoustic time difference curve and a density curve, matching and calibrating according to the similarity of the synthetic seismic records and the actual seismic records beside the wells, establishing a time-depth relationship of each well, and determining the corresponding positions of geological layers on a time domain seismic section; performing seismic data horizon interpretation on the whole area according to the calibrated position of the well stratification on the seismic section;
Step two, determining the influence range of a fault shadow area;
Step three, a time domain construction distortion calculation formula is established, and the time domain construction distortion is calculated;
a time domain construction distortion calculation formula:
Formula (1)
In formula (1): Δt is the time domain distortion, which is the double-pass time, ms; d is the thickness of the speed anomaly layer, m; v 1 is the speed of the abnormal speed layer, m/s; v 2 is the velocity of the normal formation adjacent to the abnormal layer, m/s; d is obtained from seismic interpretation in combination with well data: if the abnormal layer is completely broken, the thickness of the broken layer is the thickness of the stratum; if the abnormal layer is partially broken, the breaking thickness is a vertical breaking distance; v 1 and v 2 are obtained from the borehole acoustic time difference curve;
Step four, adjusting the interpretation horizon of the fault shadow zone according to the time domain construction distortion, and obtaining a corrected time domain interpretation horizon; the method comprises the following steps:
if the fault shadow area earthquake event is pulled up, the interpretation horizon is moved downwards according to the magnitude of the distortion; if the fault shadow area earthquake event is pulled down on the same phase axis, the interpretation horizon is moved upwards according to the magnitude of the distortion, so that the horizon trend of the fault shadow area is consistent with that of the normal stratum, and the interpretation of the full research area is conducted, so that a corrected time domain interpretation horizon is obtained;
step five, modifying the synthetic record calibration position of the fault shadow zone well according to the corrected time domain interpretation horizon, and establishing a reasonable space velocity field; the method comprises the following steps:
modifying the calibrated position of the well drilling synthetic record in the shadow zone according to the corrected time domain interpretation horizon, so that the well layering of the synthetic seismic record is matched with the corrected interpretation horizon to obtain the average stratum speed consistent with the normal stratum, and establishing a space velocity field by taking the interpretation horizon as a constraint;
And step six, performing time depth conversion on the corrected time domain interpretation horizon by using the space velocity field to obtain a real depth domain horizon.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202410329354.4A CN117930360B (en) | 2024-03-21 | 2024-03-21 | Method for correcting fault shadows in post-stack seismic data |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202410329354.4A CN117930360B (en) | 2024-03-21 | 2024-03-21 | Method for correcting fault shadows in post-stack seismic data |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN117930360A CN117930360A (en) | 2024-04-26 |
| CN117930360B true CN117930360B (en) | 2024-06-04 |
Family
ID=90755995
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202410329354.4A Active CN117930360B (en) | 2024-03-21 | 2024-03-21 | Method for correcting fault shadows in post-stack seismic data |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN117930360B (en) |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5638338A (en) * | 1995-10-16 | 1997-06-10 | Peterson; Fred M. | Seismic processing apparatus and method |
| CN108107473A (en) * | 2017-12-12 | 2018-06-01 | 中国石油天然气集团有限公司 | Seismic migration time section constructs the bearing calibration of distortion phenomenon |
| CN113945978A (en) * | 2020-07-15 | 2022-01-18 | 中国石油天然气股份有限公司 | Depth domain seismic data optimization method and device |
-
2024
- 2024-03-21 CN CN202410329354.4A patent/CN117930360B/en active Active
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5638338A (en) * | 1995-10-16 | 1997-06-10 | Peterson; Fred M. | Seismic processing apparatus and method |
| CN108107473A (en) * | 2017-12-12 | 2018-06-01 | 中国石油天然气集团有限公司 | Seismic migration time section constructs the bearing calibration of distortion phenomenon |
| CN113945978A (en) * | 2020-07-15 | 2022-01-18 | 中国石油天然气股份有限公司 | Depth domain seismic data optimization method and device |
Non-Patent Citations (1)
| Title |
|---|
| 基于WSN 的煤矿井下监控网络平台 关键技术研究;刘晓文;CNKI博士学位论文全文库;20100215;全文 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN117930360A (en) | 2024-04-26 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Yang et al. | Integrated application of 3D seismic and microseismic data in the development of tight gas reservoirs | |
| CN103576200A (en) | Low signal-to-noise ratio zone shallow wave impedance interface static correction method | |
| Niyazi et al. | Post-rift magmatism and hydrothermal activity in the central offshore Otway Basin and implications for igneous plumbing systems | |
| WONHAM et al. | Tectonic control on sedimentation, erosion and redeposition of Upper Jurassic sandstones, Central Graben, North Sea | |
| Karim et al. | Seismic reservoir characterization using model based post-stack seismic inversion: in case of Fenchuganj gas field, Bangladesh | |
| Fujimoto et al. | DAS 3DVSP survey at Stratigraphic Test Well (Hydrate-01) | |
| CN117930360B (en) | Method for correcting fault shadows in post-stack seismic data | |
| CN106990433B (en) | Identification method for micro erosion groove in bump area | |
| CN115857047A (en) | Comprehensive prediction method for seismic reservoir | |
| De Matteis et al. | 1-D P-velocity models of Mt. Vesuvius volcano from the inversion of TomoVes96 first arrival time data | |
| Su et al. | Low relief structure interpretation and mapping of the Donghe Sandstone thin reservoir based on seismic data | |
| CN117930359B (en) | Method for correcting fault shadows in post-stack seismic data by establishing high-precision velocity fields | |
| Tilbury et al. | Pluto 4D—Australia’s first 4D over a gas field is an outstanding success | |
| Esmaeilpour et al. | Pore Pressure Prediction Using Model Based Seismic Inversion and Downhole Measurements | |
| CN117950053B (en) | Method for identifying fault shadows in seismic data by using average speed | |
| Giustiniani et al. | 3D seismic data for shallow aquifers characterisation | |
| CN110780345A (en) | Three-dimensional velocity analysis method for tunnel advanced seismic exploration seismic data | |
| Roth et al. | Challenges related to oyster floatstones in Vaca Muerta development: Visualization on PSTM, PSDM and diffraction imaging | |
| Birt et al. | Delivering a step-change in imaging from Indonesia’s first ocean bottom node 3D seismic survey at Tangguh | |
| Zhang | Analysis of factors affecting residual moveout picking and solutions | |
| US20240142648A1 (en) | Method and system for estimating converted-wave statics | |
| Jun et al. | Integrated reservoir characterization of low resistivity thin beds using three-dimensional modeling for natural gas exploration | |
| CN113589367B (en) | Method for correcting nearby structure trend based on area conservation and large fracture | |
| Miller et al. | High resolution seismic reflection images of New Jersey coastal aquifers | |
| Hakim et al. | Subsurface velocity measurement |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |