Post‐MAP migration of crosswell seismic data

1997 ◽  
Author(s):  
Joongmoo Byun ◽  
James W. Rector
Keyword(s):  
Seismic Data ◽  
Map Migration

Leading-order seismic imaging using curvelets

Geophysics ◽  
2007 ◽  
Vol 72 (6) ◽  
pp. S231-S248 ◽  
Author(s):  
Huub Douma ◽  
Maarten V. de Hoop
Keyword(s):  
Seismic Data ◽  
Order Approximation ◽  
Angular Frequency ◽  
Leading Order ◽  
Numerical Examples ◽  
Depth Migration ◽  
Map Migration ◽  
Kirchhoff Depth Migration ◽  
Homogeneous Media ◽  
Spatial Support

Curvelets are plausible candidates for simultaneous compression of seismic data, their images, and the imaging operator itself. We show that with curvelets, the leading-order approximation (in angular frequency, horizontal wavenumber, and migrated location) to common-offset (CO) Kirchhoff depth migration becomes a simple transformation of coordinates of curvelets in the data, combined with amplitude scaling. This transformation is calculated using map migration, which employs the local slopes from the curvelet decomposition of the data. Because the data can be compressed using curvelets, the transformation needs to be calculated for relatively few curvelets only. Numerical examples for homogeneous media show that using the leading-order approximation only provides a good approximation to CO migration for moderate propagation times. As the traveltime increases and rays diverge beyond the spatial support of a curvelet; however, the leading-order approximation is no longer accurate enough. This shows the need for correction beyond leading order, even for homogeneous media.

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.

Adjoint-state reverse time migration of 4C data: Finite-frequency map migration for marine seismic imaging

Geophysics ◽  
2013 ◽  
Vol 78 (2) ◽  
pp. WA159-WA172 ◽  
Author(s):  
Clement Fleury ◽  
Ivan Vasconcelos
Keyword(s):  
Seismic Data ◽  
Finite Frequency ◽  
Reverse Time ◽  
Reverse Time Migration ◽  
Directional Information ◽  
Time Migration ◽  
Adjoint State ◽  
Dual Source ◽  
Map Migration ◽  
Marine Seismic

Recent advances in marine seismic acquisition allow for the recording of vector-acoustic ([VA] pressure and particle velocity) seismic data from dual-source configurations, i.e., using monopole as well as dipole sources. VA reverse time migration (RTM) can be custom designed to accurately handle amplitude and directivity information from 4C seismic data. We present a method for multicomponent RTM that is based on an adjoint-state formulation using the full VA wave equations for pressure and corresponding displacement fields. This method takes advantage of the directional finite-frequency information contained in the 4C acoustic fields by using source and receiver weighting operators in the adjoint-state imaging scheme. With this adjoint-state method, the source and receiver radiation properties are tailored by choosing specific weighting operators. Weighting operators were chosen so that source- and receiver-side ghost arrivals are jointly migrated with primary energy. Because the dipole field components (e.g., components of particle displacement or acceleration) are proportional to the spatial gradient components of the pressure field, our method is in fact a formulation for reverse-time map migration that images pressure fields while jointly using the directional information contained in its full 3C gradients. As a result, our reverse time 4C map migration method yields less aperture- and sampling-related artifacts when compared to imaging of the pressure-only or 2C seismic data. In addition, our method sets a framework for full-waveform inversion using dual-source 4C seismic data. We demonstrated our findings with synthetic data, including a subsalt imaging example.

Formation geological depth image according to refraction and reflection marine seismic data

2017 ◽  
Vol 39 (6) ◽  
pp. 106-121
Author(s):  
A. O. Verpahovskaya ◽  
V. N. Pilipenko ◽  
Е. V. Pylypenko
Keyword(s):  
Seismic Data ◽  
Depth Image ◽  
Marine Seismic

Accurate imaging of surface seismic data without a velocity model

2007 ◽  
Author(s):  
Sverre Brandsberg-Dahl ◽  
Brian E. Hornby ◽  
Xiang Xiao
Keyword(s):  
Seismic Data ◽  
Velocity Model ◽  
Accurate Imaging

Combining Wireline and LWD Borehole Seismic Data for Drilling HPHT Well: A Novel Approach

2009 ◽  
Author(s):  
Teck Kean Lim ◽  
Aqil Ahmed ◽  
Muhammad Antonia Gibrata ◽  
Gunawan Taslim
Keyword(s):  
Seismic Data ◽  
Novel Approach ◽  
Borehole Seismic

Integrated Analysis of Borehole and Surface Seismic Data to Resolve Seismic Uncertainties in the Gulf Of Suez

2014 ◽  
Author(s):  
Mohamed S El-Hateel ◽  
Parvez Ahmad ◽  
Ahmed Hesham A Ismail ◽  
Islam A M Henaish ◽  
Ahmed Ashraf
Keyword(s):  
Seismic Data ◽  
Integrated Analysis ◽  
Gulf Of Suez
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