Correction for water velocity variations and tidal statics

Lacombe, C.; Schultzen, Jon; Butt, Suhail; Lecerf, D.

doi:10.1190/1.2370124

Cited by 12 publications

(2 citation statements)

References 1 publication

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“…Fortunately, the application of travel-time/velocity analysis of the seismic data itself can be used to provide a good direct estimate of the water velocity (Mackay et al, 2003). In a separate treatment, Lacombe et al (2006) applied the method of Landrø and Stammeijer (2004) to the water layer by using travel-times of waves reflected from the water bottom to estimate the desired time-shift correction. This technique works for deep-to-moderate water depths of a few hundred metres.…”

Section: Tide and Seawater Velocity Variationsmentioning

confidence: 99%

“…In the data, the effect of tides on time‐shifts is visible as obvious striping parallel to the acquisition of sail lines or ‘jitter’ in crossline sections (Barley, 1999; Lacombe et al., 2006). This arises as surveys are shot daily in batches of sail lines, which sample different environmental conditions.…”

Section: Acquisition and Processing‐related Errorsmentioning

confidence: 99%

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A review and analysis of errors in post‐stack time‐shift interpretation

MacBeth

Izadian

2023

Geophysical Prospecting

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This study complements two earlier papers on the interpretation and estimation of post‐stack time‐shifts that detail the most popular measurement methods to date. In this current work, the focus is on describing the magnitude and identifying the origin of the uncertainty present in these time‐shift values. We also consider how the underlying assumptions behind conventional time‐shift estimation methods can contribute to the inadequate resolution of the subsurface time‐lapse changes. The various errors fall into three broad categories: (1) those related to intrinsic data limits that cannot be avoided; (2) those associated with seismic measurement methods that can be corrected with some effort; and finally (3) those that arise due to approximations to the wave physics made during the design or implementation of the methods. In the first category are limitations due to sampling rate and signal‐to‐noise ratio, and wavelet interferences resulting from the narrow band nature of the seismic data and the heterogeneous nature of the geology itself. The effects produce errors of typically a fraction of a millisecond, but exceptionally in 4D data with poor repeatability up to 1 ms. In the second category are acquisition and processing errors. These are usually of the order of a few milliseconds but can reach up to 10s of milliseconds and are, therefore, essential to correct. It is possible to correct the effects of tides and seawater variations in marine acquisition if these changes are monitored and measured. Navigation and timing are identified as issues to consider carefully. For land data, daily and seasonal near‐surface variations are still problematic, and source and sensors must be buried to deliver interpretable time‐shifts. The impact of choices made during processing can be significant but is specific to the workflow and dataset and thus cannot be generically assessed. However, the effects from residual multiples can be identified and treated. Of moderate importance is the third category of errors, which consists of four items. Of these, the effect of lateral image shifts and amplitude effects are judged to play a minor role. Deviation from the assumption of vertical ray‐paths during post‐stack analysis appears to be of concern only for reservoirs with noticeably dipping structures and strong contrasts. The effect of pre‐stack variations on the post‐stack measurements remains a topic to be more thoroughly examined, and the conclusion is unclear. Finally, it is apparent that uncertainties in all categories are strongly dependent on the field setting and geographical location.

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Section: Tide and Seawater Velocity Variationsmentioning

confidence: 99%

Section: Acquisition and Processing‐related Errorsmentioning

confidence: 99%

A review and analysis of errors in post‐stack time‐shift interpretation

MacBeth

Izadian

2023

Geophysical Prospecting

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A simple method of correction for profile-length water-column height variations in high-resolution, shallow-water seismic data

Kim

Lee

et al. 2017

Ocean Sci. J.

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Processing solutions for wide‐azimuth data: Outcome from a WATS field experiment in deepwater Gulf of Mexico

Magesan

Ferran

Kaculini

et al. 2007

SEG Technical Program Expanded Abstracts 2007

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Wide Azimuth Towed Streamer (WATS) acquisition has already proved to be a key technique in improving seismic imaging, especially in complex areas such as sub-salt plays. In 2006, a WATS field experiment was conducted in a deep water area of the Gulf of Mexico. The main purpose was to challenge recently developed 3D processing algorithms and find the most suitable processing strategy for a wide azimuth dataset. The results indicate that a 3D shot based processing sequence is an effective solution that accommodates the effects related to the multi-pass acquisition method and realizes the full benefit of the recorded 3D wide azimuth wave field.

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Correction for water velocity variations and tidal statics

Cited by 12 publications

References 1 publication

A review and analysis of errors in post‐stack time‐shift interpretation

A review and analysis of errors in post‐stack time‐shift interpretation

A simple method of correction for profile-length water-column height variations in high-resolution, shallow-water seismic data

Processing solutions for wide‐azimuth data: Outcome from a WATS field experiment in deepwater Gulf of Mexico

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