scholarly journals Multifocusing imaging over an irregular topography

Geophysics ◽  
2002 ◽  
Vol 67 (2) ◽  
pp. 639-643 ◽  
Author(s):  
Boris Gurevich ◽  
Shemer Keydar ◽  
Evgeny Landa
Keyword(s):  
Seismic Data ◽  
Effective Solution ◽  
Static Corrections ◽  
Irregular Topography

If seismic data are acquired over an irregular topography, standard elevation statics methods may be inaccurate because the assumption of vertical raypaths will no longer be valid. An effective solution to the problem of irregular topography can be found through the use of the multifocusing method, in which large supergathers of seismic traces are stacked, each of which can span many common midpoint (CMP) gathers. This can be done by extending the multifocusing moveout formula to explicitly account for nonzero elevations of the source and receiver, as well as their horizontal coordinates. Implementation of this formula into the multifocusing algorithm is straightforward because estimating the necessary raypath information (i.e., emergence angles) is an integral part of the algorithm. The extended multifocusing moveout correction can be applied directly to the data acquired in areas of irregular topography without the need for prior elevation static corrections. Synthetic tests on such data show that the proposed technique results in a better alignment of reflection events.

scholarly journals Integrated magnetotelluric and seismic investigation of Cenozoic graben structure near Obrzycko, Poland

2021 ◽  
Author(s):  
Adam Cygal ◽  
Michał Stefaniuk ◽  
Anna Kret
Keyword(s):  
Seismic Data ◽  
Geophysical Methods ◽  
Geological Structure ◽  
Data Sets ◽  
Low Velocity ◽  
Shallow Subsurface ◽  
Geophysical Model ◽  
Novel Approach ◽  
Loose Deposits ◽  
Static Corrections

AbstractThis article presents the results of an integrated interpretation of measurements made using Audio-Magnetotellurics and Seismic Reflection geophysical methods. The obtained results were used to build an integrated geophysical model of shallow subsurface cover consisting of Cenozoic deposits, which then formed the basis for a detailed lithological and tectonic interpretation of deeper Mesozoic sediments. Such shallow covers, consisting mainly of glacial Pleistocene deposits, are typical for central and northern Poland. This investigation concentrated on delineating the accurate geometry of Obrzycko Cenozoic graben structure filled with loose deposits, as it was of great importance to the acquisition, processing and interpretation of seismic data that was to reveal the tectonic structure of the Cretaceous and Jurassic sediments which underly the study area. Previously, some problems with estimation of seismic static corrections over similar grabens filled with more recent, low-velocity deposits were encountered. Therefore, a novel approach to estimating the exact thickness of such shallow cover consisting of low-velocity deposits was applied in the presented investigation. The study shows that some alternative geophysical data sets (such as magnetotellurics) can be used to significantly improve the imaging of geological structure in areas where seismic data are very distorted or too noisy to be used alone

scholarly journals Time-lapse difference static correction using prestack crosscorrelations: 4D seismic image enhancement case from Ketzin

Geophysics ◽  
2014 ◽  
Vol 79 (6) ◽  
pp. B243-B252 ◽  
Author(s):  
Peter Bergmann ◽  
Artem Kashubin ◽  
Monika Ivandic ◽  
Stefan Lüth ◽  
Christopher Juhlin
Keyword(s):  
Seismic Data ◽  
Time Lapse ◽  
Data Sets ◽  
Storage Site ◽  
Data Set ◽  
Near Surface ◽  
Static Correction ◽  
Seismic Image ◽  
Static Corrections ◽  
4D Seismic

A method for static correction of time-lapse differences in reflection arrival times of time-lapse prestack seismic data is presented. These arrival-time differences are typically caused by changes in the near-surface velocities between the acquisitions and had a detrimental impact on time-lapse seismic imaging. Trace-to-trace time shifts of the data sets from different vintages are determined by crosscorrelations. The time shifts are decomposed in a surface-consistent manner, which yields static corrections that tie the repeat data to the baseline data. Hence, this approach implies that new refraction static corrections for the repeat data sets are unnecessary. The approach is demonstrated on a 4D seismic data set from the Ketzin [Formula: see text] pilot storage site, Germany, and is compared with the result of an initial processing that was based on separate refraction static corrections. It is shown that the time-lapse difference static correction approach reduces 4D noise more effectively than separate refraction static corrections and is significantly less labor intensive.

Seismogravimetric Methodology: Specifics and Applicability to the Siberian Platform

2021 ◽  
Vol 62 (07) ◽  
pp. 790-797
Author(s):  
V.A. Kochnev
Keyword(s):  
Siberian Platform ◽  
Seismic Data ◽  
Western Slope ◽  
Static Corrections ◽  
Comparison Of The Results ◽  
Experimental Processing

Abstract —The paper presents a new seismogravimetric method for estimating static corrections used in processing of seismic data and in construction of time and depth sections. The method efficiency is demonstrated by comparison of the results of industrial and new experimental processing of data for the western slope of the Nepa–Botuoba anteclise.

Approximating subsurface structure in areas of severe subsea erosion—A nonprocessing technique

Geophysics ◽  
1989 ◽  
Vol 54 (11) ◽  
pp. 1397-1409
Author(s):  
Fred W. Lishman ◽  
Michael N. Christos
Keyword(s):  
Seismic Data ◽  
Seismic Reflection ◽  
Velocity Model ◽  
Subsurface Structure ◽  
Submarine Canyons ◽  
Arrival Times ◽  
Sea Floor ◽  
Static Corrections ◽  
Map Migration ◽  
Made In

Severe subsea erosion distorts seismic reflection times and velocity analyses and makes determining subsurface structure difficult. Although data reprocessing is the logical solution for removing these distortions, reprocessing can be expensive. We present a case history describing a nonprocessing depth‐conversion technique using a geologic erosional model. A grid of common‐midpoint seismic data located in and around several submarine canyons was used for this study. Establishing a geologic erosional model requires an accurate representation of the sea floor, which we obtain by map migration of the sea‐floor reflection. A velocity model was developed using only those analyses not adversely affected by sea‐floor erosion. To remove the effects of erosion from the arrival times of a mapped horizon, static corrections (velocity replacement and compaction) were developed. We replaced the water velocity in the eroded section with depth‐equivalent rock velocities from the velocity model. The compaction correction, which was derived empirically, is based on the assumption that porosity restoration occurred in the sediments beneath the canyons when erosion reduced the overlying pressure. Compaction correction in conjunction with velocity replacement produced structure maps (time and depth) that exhibit only minor effects of erosion. These results were further improved by applying dynamic corrections obtained by ray tracing a subsurface model to determine the traveltime through the water for the reflection from the mapped horizon. Our final structure maps demonstrate that a geologically reasonable structural interpretation in depth can be made in areas of severe subsea erosion without reprocessing the data.

The Application of Seismic Data Processing Technology in Kongdian Area

2013 ◽  
Vol 663 ◽  
pp. 876-881
Author(s):  
Qiang Lan ◽  
Qian Zhang
Keyword(s):  
Seismic Data ◽  
Oil And Gas ◽  
Low Frequency ◽  
Processing Technology ◽  
Bohai Bay ◽  
Well Control ◽  
Oil And Gas Exploration ◽  
Time Migration ◽  
Energy Compensation ◽  
Static Corrections

Kongdian is located in the eastern part of Bohai Bay. This region has good prospects for oil and gas exploration, but the seismic geologic condition is very complex. After several stages of exploration, a number of significant exploration results have been achieved, but the gradually exposed problems restricted the exploration to go further. In a new round of exploration, the high and low frequency energy compensation technology, advantaged band deconvolution processing technology, dividing frequency high-precision residual static corrections, high-resolution well control-target wavelet deconvolution technology, common scattering point imaging technology and prestack time migration processing technology have been used to improve exploration accuracy. Five potential areas were found in this region according to the new processed seismic data and subsequent interpretation work, achieving the pleasant situation of initial success following the exploration in that year.

Modeling the effect of static errors in areal seismic data caused by glacial erosion over carbonate reefs

Geophysics ◽  
1984 ◽  
Vol 49 (1) ◽  
pp. 1-16
Author(s):  
Janet S. Kotcher ◽  
G. H. F. Gardner ◽  
John A. McDonald
Keyword(s):  
Data Collection ◽  
Surface Topography ◽  
Seismic Data ◽  
Structural Features ◽  
Raw Data ◽  
Areal Data ◽  
Instantaneous Phase ◽  
Reasonable Cost ◽  
Static Corrections ◽  
Northern Michigan

An effective way of exploring for structural features is by areal seismic methods. In addition to finding depth and location, the area of a structure may be determined at a reasonable cost. However, the efficacy of the areal method can be rapidly destroyed by static shifts in the seismic traces. In this paper we investigate the effect of statics on the crossed array method of areal data collection. Seismic data were collected in the northern Michigan reef trend, an area containing numerous small pinnacle reefs. The surface topography is flat, but it contains deep erosional valleys filled with glacial drift which produce time shifts in the data. The data were processed without static corrections. To predict the effect of static errors, a model was designed to produce data resembling those taken over a pinnacle reef. Seismic data were collected over this model by a method simulating the crossed array technique. Horizontal displays of the power envelope and the instantaneous phase of the migrated data were generated at a specified one‐way time, when various source and receiver dependent statics had been introduced into the raw data. The statics were designed to simulate the effect of glacial drift. If the diameter of the migration aperture is significantly larger than the distance along the source and receiver lines affected by statics, the effect on the migrated output is minimal. However, if the distance affected by statics approaches the diameter of the migration aperture, the effects are significant.

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