3‐D pseudospectral prestack reverse‐time migration with application to reverse‐VSP data

1991 ◽  
Author(s):  
How‐Wei Chen ◽  
George A. McMechan
Keyword(s):  
Reverse Time ◽  
Reverse Time Migration ◽  
Time Migration ◽  
Vsp Data

Imaging reflection-blind areas using transmitted PS-waves

Geophysics ◽  
2006 ◽  
Vol 71 (6) ◽  
pp. S241-S250 ◽  
Author(s):  
Yi Luo ◽  
Qinglin Liu ◽  
Yuchun E. Wang ◽  
Mohammed N. AlFaraj
Keyword(s):  
Mode Conversion ◽  
Imaging Techniques ◽  
Reverse Time ◽  
Reverse Time Migration ◽  
Reflected Waves ◽  
Prestack Migration ◽  
Reflection Data ◽  
Time Migration ◽  
Transmitted Waves ◽  
Vsp Data

We illustrate the use of mode-converted transmitted (e.g., PS- or SP-) waves in vertical seismic profiling (VSP) data for imaging areas above receivers where reflected waves cannot illuminate. Three depth-domain imaging techniques — move-out correction, common-depth-point (CDP) mapping, and prestack migration — are described and used for imag-ing the transmitted waves. Moveout correction converts an offset VSP trace into a zero-offset trace. CDP mapping maps each sample on an input trace to the location where the mode conversion occurs. For complex media, prestack migration (e.g., reverse-time migration) is used. By using both synthetic and field VSP data, we demonstrate that images derived from transmissions complement those from reflections. As an important application, we show that transmitted waves can illuminate zones above highly de-viated or horizontal wells, a region not imaged by reflection data. Because all of these benefits are obtained without extra data acquisition cost, we believe transmission imag-ing techniques will become widely adopted by the oil in-dustry.

Pre-Stack Depth Migration of High Resolution Distributed Acoustic Sensing VSP

2021 ◽  
Author(s):  
Herurisa Rusmanugroho ◽  
Makky Sandra Jaya ◽  
M Hafizal Zahir ◽  
M Faizal Rahim
Keyword(s):  
High Resolution ◽  
Fiber Optic ◽  
Seismic Profile ◽  
Reverse Time ◽  
Reverse Time Migration ◽  
Acoustic Sensing ◽  
Depth Migration ◽  
Time Migration ◽  
Vsp Data ◽  
Distributed Acoustic Sensing

Abstract The performance of pre-stack depth migration (PSDM) on the fiber optic, distributed acoustic sensing (DAS), vertical seismic profile (VSP) data has rarely been reported. We show the results of PSDM for the fiber optic cables, newly developed and tested at a field in Canada. We apply Kirchhoff migration, Fresnel volume migration and reverse time migration (RTM) to the walkway VSP data to obtain high resolution images of the shallow to deeper structures and provide the performance analysis of the migration methods for the DAS VSP data.

Up/down and P/S decompositions of elastic wavefields using complex seismic traces with applications to calculating Poynting vectors and angle-domain common-image gathers from reverse time migrations

Geophysics ◽  
2016 ◽  
Vol 81 (4) ◽  
pp. S181-S194 ◽  
Author(s):  
Wenlong Wang ◽  
George A. McMechan ◽  
Chen Tang ◽  
Fei Xie
Keyword(s):  
Fourier Transforms ◽  
Original Data ◽  
Complex Data ◽  
Reverse Time ◽  
Reverse Time Migration ◽  
S Wave ◽  
Time Migration ◽  
Vsp Data ◽  
Poynting Vectors ◽  
Over Time

Separations of up- and down-going as well as of P- and S-waves are often a part of processing of multicomponent recorded data and propagating wavefields. Most previous methods for separating up/down propagating wavefields are expensive because of the requirement to save time steps to perform Fourier transforms over time. An alternate approach for separation of up-and down-going waves, based on extrapolation of complex data traces is extended from acoustic to elastic, and combined with P- and S-wave decomposition by decoupled propagation. This preserves all the information in the original data and eliminates the need for a Fourier transform over time, thereby significantly reducing the storage cost and improving computational efficiency. Wavefield decomposition is applied to synthetic elastic VSP data and propagating wavefield snapshots. Poynting vectors obtained from the particle velocity and stress fields after P/S and up/down decompositions are much more accurate than those without because interference between the corresponding wavefronts is significantly reduced. Elastic reverse time migration with the P/S and up/down decompositions indicated significant improvement compared with those without decompositions, when applied to elastic data from a portion of the Marmousi2 model.

scholarly journals Reverse time migration of 3D vertical seismic profile data

Geophysics ◽  
2016 ◽  
Vol 81 (1) ◽  
pp. S31-S38 ◽  
Author(s):  
Ying Shi ◽  
Yanghua Wang
Keyword(s):  
Parallel Implementation ◽  
Processing Unit ◽  
Reverse Time ◽  
Reverse Time Migration ◽  
Time Step ◽  
Absorbing Boundary ◽  
Data Set ◽  
Time Migration ◽  
Wavefield Simulation ◽  
Vsp Data

Reverse time migration (RTM) has shown increasing advantages in handling seismic images of complex subsurface media, but it has not been used widely in 3D seismic data due to the large storage and computation requirements. Our prime objective was to develop an RTM strategy that was applicable to 3D vertical seismic profiling (VSP) data. The strategy consists of two aspects: storage saving and calculation acceleration. First, we determined the use of the random boundary condition (RBC) to save the storage in wavefield simulation. An absorbing boundary such as the perfect matching layer boundary is often used in RTM, but it has a high memory demand for storing the source wavefield. RBC is a nonabsorbing boundary and only stores the source wavefield at the two maximum time steps, then repropagates the source wavefield backwards at every time step, and hence, it significantly reduces the memory requirement. Second, we examined the use of the graphic processing unit (GPU) parallelization technique to accelerate the computation. RBC needs to simulate the source wavefield twice and doubles the computation. Thus, it is very necessary to realize the RTM algorithm by GPU, especially for a 3D VSP data set. GPU and central processing unit (CPU) collaborated parallel implementation can greatly reduce the computation time, where the CPU performs serial code, and the GPU performs parallel code. Because RBC does not need the same huge amount of storage as an absorbing boundary, RTM becomes practically applicable for 3D VSP imaging.

Determination of salt proximity by wave‐field imaging of transmitted energy

Geophysics ◽  
1988 ◽  
Vol 53 (8) ◽  
pp. 1109-1112 ◽  
Author(s):  
George A. McMechan ◽  
Liang‐Zie Hu ◽  
Douglas Stauber
Keyword(s):  
Acoustic Waves ◽  
Seismic Profile ◽  
Reverse Time ◽  
Reverse Time Migration ◽  
Vertical Seismic Profile ◽  
Wave Fields ◽  
Time Migration ◽  
Vsp Data ◽  
Field Imaging

Prestack reverse‐time migration for acoustic waves has recently been developed for vertical seismic profile (VSP) data (Chang and McMechan, 1986) and for cross‐hole (CH) data (Hu et al., 1988). Both sets of authors use the same migration software and produce images from the scattered (reflected and diffracted) energy in the recorded wave fields.

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