Imaging through Gas Clouds - a Case History from the Gulf of Mexico

Knapp, Steve; Payne, Nigel; Johns, Tony

doi:10.3997/2214-4609-pdb.5.a009

Cited by 4 publications

(3 citation statements)

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“…For example, in seismic imaging for oil and gas exploration, P-and S-wave reflections can be imaged independently. In the presence of gas clouds and fractures, the P-waves are strongly attenuated, while Swaves are less affected, and S-wave images provide valuable structural information from reservoirs [1], [2]. In computational seismology, most imaging methods for earthquake and microseismic events involve picking the P-and S-wave arrival times.…”

Section: Introductionmentioning

confidence: 99%

CNN-tuned spatial filters for P- and S-wave decomposition and applications in elastic imaging

Wang¹,

Ma²,

McMechan³

2021

Preprint

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P-and S-wave decomposition is essential for imaging multi-component seismic data in elastic media. A data-driven workflow is proposed to obtain a set of spatial filters that are highly accurate and artifact-free in decomposing the P-and Swaves in 2D isotropic elastic wavefields. The filters are formulated initially by inverse Fourier transforms of the wavenumberdomain operators, and then are tuned in a convolutional neural network to improve accuracy using synthetic snapshots. Spatial filters are flexible for decomposing P-and S-waves at any time step without performing Fourier transforms over the entire wavefield snapshots, and thus are suitable for target-oriented imaging. Snapshots from synthetic data show that the network-tuned spatial filters can decompose P-and S-waves with improved decomposition accuracy compared with other space-domain PS decomposition methods. Elastic reverse-time migration using Pand S-waves decomposed from the proposed algorithm shows reduced artifacts in the presence of a high velocity contrast.

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Section: Introductionmentioning

confidence: 99%

CNN-tuned spatial filters for P- and S-wave decomposition and applications in elastic imaging

Wang¹,

Ma²,

McMechan³

2021

Preprint

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“…Vector-wave-based, elastic reverse time migration (ERTM) can avoid polarity reversal in Pressure-Shear (PS) images (Wang et al 2016a, b;Du et al 2017), and has a significant advantage in imaging arbitrarily complex structures without dip limitations or shadow zones (Baysal et al 1983;McMechan 1983), imaging in the presence of gas clouds (Thomsen et al 1997;Knapp et al 2001), detecting fractures (Li 1998), and improving the ability to characterize lithology (Shahraeeni et al 2012). Despite these developments, some artifacts inevitably exist in the migrated images.…”

Section: Introductionmentioning

confidence: 99%

Analytic Acoustic–Elastic Coupled Equations and Their Application in Vector-Wave-Based Imaging of Ocean Bottom 4C Data

Geng

2019

Pure Appl. Geophys.

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In conventional vector-wave-based elastic reversetime migration, there are two types of artifacts: low-frequency artifacts and nonphysical artifacts. Vector-decomposition-based acoustic-elastic coupled equations are effective in suppressing nonphysical artifacts by using ocean bottom four component (4C) seismic data for receiver-side tensorial extrapolation. We introduce up/down-going wave separation into the vector-decompositionbased acoustic-elastic coupled equations, and deduce novel analytic acoustic-elastic coupled equations. With these novel equations, we can obtain the source-side and receiver-side up-going and down-going P/S-wave vectors in wavefield propagation, and effectively suppress both of the artifacts in vector-wave-based elastic reverse-time migration by combining receiver-side tensorial extrapolation and the decomposed vector-wave-based imaging conditions. Examples using synthetic data and field data are presented to illustrate the validity and effectiveness of our method.

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“…Margrave et al [10] reported success interpreting channel sands with 3C data in Blackfoot Field by using V p /V s measurement. Knapp et al [11] presented a case study in Gulf of Mexico to show the significance of converted-wave data in imaging through gas clouds. The importance of 4C data for lithology and fluid estimation has been showed by Engelmark [12].…”

Section: Introductionmentioning

confidence: 99%

Advantages of Shear Wave Seismic in Morrow Sandstone Detection

Singh

2011

International Journal of Geophysics

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The Upper Morrow sandstones in the western Anadarko Basin have been prolific oil producers for more than five decades. Detection of Morrow sandstones is a major problem in the exploration of new fields and the characterization of existing fields because they are often very thin and laterally discontinuous. Until recently compressional wave data have been the primary resource for mapping the lateral extent of Morrow sandstones. The success with compressional wave datasets is limited because the acoustic impedance contrast between the reservoir sandstones and the encasing shales is small. Here, we have performed full waveform modeling study to understand the Morrow sandstone signatures on compressional wave (P-wave), converted-wave (PS-wave) and pure shear wave (S-wave) gathers. The contrast in rigidity between the Morrow sandstone and surrounding shale causes a strong seismic expression on the S-wave data. Morrow sandstone shows a distinct high amplitude event in pure S-wave modeled gathers as compared to the weaker P- and PS-wave events. Modeling also helps in understanding the adverse effect of interbed multiples (due to shallow high velocity anhydrite layers) and side lobe interference effects at the Morrow level. Modeling tied with the field data demonstrates that S-waves are more robust than P-waves in detecting the Morrow sandstone reservoirs.

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Imaging through Gas Clouds - a Case History from the Gulf of Mexico

Cited by 4 publications

References 0 publications

CNN-tuned spatial filters for P- and S-wave decomposition and applications in elastic imaging

CNN-tuned spatial filters for P- and S-wave decomposition and applications in elastic imaging

Analytic Acoustic–Elastic Coupled Equations and Their Application in Vector-Wave-Based Imaging of Ocean Bottom 4C Data

Advantages of Shear Wave Seismic in Morrow Sandstone Detection

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