Accounting for sea surface variation in deghosting – a novel approach applied to a 3D dataset offshore west Africa

In this paper, we propose a novel three‐dimensional receiver deghosting algorithm that is capable of deghosting both horizontal and slanted streamer data in a theoretically consistent manner. Our algorithm honours wave propagation phenomena in a true three‐dimensional sense and frames the three‐dimensional receiver deghosting problem as a Lasso problem. The ultimate goal is to minimise the mismatch between the actual measurements and the simulated wavefield with an L1 constraint applied in the extended Radon space to handle the underdetermined nature of this problem. We successfully demonstrate our algorithm on a modified three‐dimensional EAGE/SEG Overthrust model and a Red Sea marine dataset.

Section: Theory and Algorithmmentioning

confidence: 94%

Three‐dimensional receiver deghosting of seismic streamer data using L1 inversion and redundant extended radon dictionary

Sun¹,

Verschuur

2018

“…An alternative is to fix the reflection coefficient but play with the effective receiver depth (Hardwick et al . ). These topics, despite their interest, are approximations to the ghost models that we derived from the Kirchhoff integral and fall beyond the scope of this paper.…”

Section: Numerical Examplesmentioning

confidence: 97%

“…This is based on the fact that the specular energy redirected at a rough sea surface can have more energy loss at higher than at lower frequencies, with the amount of energy loss depending on the wavelength and height of the sea surface and following the Rayleigh model (Klüver and Tabti 2015). An alternative is to fix the reflection coefficient but play with the effective receiver depth (Hardwick et al 2015). These topics, despite their interest, are approximations to the ghost models that we derived from the Kirchhoff integral and fall beyond the scope of this paper.…”

Section: Test Case 2 With Imperfect Surface Sea Conditionsmentioning

confidence: 99%

Joint up/down decomposition and reconstruction using three‐component streamers with or without ghost model: the sampling theory

Tang

Campman

2016

This paper addresses two artefacts inherent to marine towed‐streamer surveys: 1) ghost reflections and 2) too sparse a sampling in the crossline direction. A ghost reflection is generated when an upcoming reflection bounces off the sea surface back into the sensors and can, in principle, be removed by decomposing the measured wavefield into its up‐ and downgoing constituents. This process requires a dense sampling of the wavefield in both directions along and perpendicular to the streamers. A dense sampling in the latter direction is, however, often impossible due to economical and operational constraints. Recent multi‐component streamers have been designed to record the spatial gradients on top of the pressure, which not only benefits the wavefield decomposition but also facilitates a lower‐than‐Nyquist sampling rate of the pressure. In this paper, wavefield reconstruction and deghosting are posed as a joint inverse problem. We present two approaches to establish a system matrix that embeds both a deghosting and an interpolation operator. The first approach is derived with a ghost model, whereas the second approach is derived without a ghost model. The embodiment of a ghost model leads to an even lower sampling rate but relies on a more restrictive assumption on the sea surface.

“…; Hardwick et al . ; King and Poole ) may further improve the quality of single‐component data deghosting in rough sea conditions. The 3D nature of the sea surfaces can also be accounted for.…”

Section: The Influence Of the Rough Sea On The Standard Deghosting Prmentioning

confidence: 99%

How rough sea affects marine seismic data and deghosting procedures

Egorov

Glubokovskikh

Bóna

et al. 2017

A B S T R A C TMost seismic processing algorithms generally consider the sea surface as a flat reflector. However, acquisition of marine seismic data often takes place in weather conditions where this approximation is inaccurate. The distortion in the seismic wavelet introduced by the rough sea may influence (for example) deghosting results, as deghosting operators are typically recursive and sensitive to the changes in the seismic signal. In this paper, we study the effect of sea surface roughness on conventional (5-160 Hz) and ultra-high-resolution (200-3500 Hz) single-component towed-streamer data. To this end, we numerically simulate reflections from a rough sea surface using the Kirchhoff approximation. Our modelling demonstrates that for conventional seismic frequency band sea roughness can distort results of standard one-dimensional and two-dimensional deterministic deghosting. To mitigate this effect, we introduce regularisation and optimisation based on the minimum-energy criterion and show that this improves the processing output significantly. Analysis of ultra-high-resolution field data in conjunction with modelling shows that even relatively calm sea state (i.e., 15 cm wave height) introduces significant changes in the seismic signal for ultra-high-frequency band. These changes in amplitude and arrival time may degrade the results of deghosting. Using the field dataset, we show how the minimum-energy optimisation of deghosting parameters improves the processing result.