Direct Measurement of Water Velocity and Tidal Variations in Marine Seismic Acquisition

Wang, Kanglin; Hatchell, Paul; Udengaard, C.; Craft, Kenneth L.; Nodal, Fairfield; Dunn, Shaun

doi:10.1190/segam2012-0806.1

Cited by 8 publications

(2 citation statements)

References 4 publications

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“…Some recent PRM case studies report NRMSD values in the 3-5% range (e.g., Thedy et al, 2015;Buizard et al, 2013), which is considered excellent and allows for quantitative interpretation and faster survey repeat cycles, even in complex reservoirs. These results were achieved through elimination, or correction, of the most obvious sources of 4D noise, such as receiver location inaccuracy, coupling variation, time drift, and variations in the water column (e.g., Wang et al, 2015). Having eliminated these first order effects, the focus shifts increasingly to seemingly lower order effects such as, e.g., the variability of the seismic source.…”

Section: Introductionmentioning

confidence: 99%

The Impact of Wave-induced Source Variations On 4D Repeatability

Goertz¹,

Blachet²,

Wisløff³

2017

Proceedings

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Small waveform and directivity variations of marine airgun signatures due to waves interacting with the source float are a source of 4D noise. We are assessing the magnitude of this noise by first measuring the amount of variability from near-source auxiliary data and then modeling synthetic time-lapse ocean bottom seismic data with realistic source variations based on the measured statistics and standard ocean wave models. We quantify the contribution of source variations to 4D noise as a function of sea state by calculating the NRMSD attribute in the image domain. We find that up to 4% NRMSD can be attributed to source variations under realistic scenarios, with two main contributing effects: variations of individual gun signatures due to pressure changes, and array directivity variations due to the wave-induced pitch and roll of the source floats. The latter effect has a larger impact on the 4D noise in our simulations and depends more on the wave steepness rather than the wave height. While waveform variations can be addressed by a nearfield-based shot-by-shot designature, directivity variations are difficult to correct without knowledge of the sea surface shape.

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Section: Introductionmentioning

confidence: 99%

The Impact of Wave-induced Source Variations On 4D Repeatability

Goertz¹,

Blachet²,

Wisløff³

2017

Proceedings

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“…Correction of water column statics on seismic data requires a priori knowledge of the actual water velocity during surveys. Recently, an instrument called pressure inverted echo sounder (PIES) (Wang et al, 2012) was developed and used to estimate the average water velocity by measuring the depth-dependent pressure and the two-way flight time. However, the measurements from PIES are restricted to the specific location and depth at which they are planted and inaccuracies can exist in the measured velocity due to the uncertainty in the pressure-to-depth conversion.…”

Section: Introductionmentioning

confidence: 99%

Joint inversion of water velocity and node position for ocean-bottom node data

Amini

Peng

Zhao

et al. 2016

SEG Technical Program Expanded Abstracts 2016

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Variation of sound wave velocity in water (water velocity) and node positioning errors can cause strong 4D noise in ocean bottom node (OBN) time-lapse processing if they are not addressed correctly. Here we proposed a method to jointly invert the water velocity and the node position from the recorded direct arrival time in the data. We validated this method using synthetic and real OBN data examples from deep-water Gulf of Mexico.

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