GNGTS 2014 - Atti del 33° Convegno Nazionale

62 GNGTS 2014 S essione 3.1 Source double-mirror migration relies on the local planarity of the water bottom, as ghost sources S’ positioning errors can deteriorate imaging result: however, complex bathymetry can still be correctly taken into account by minor changes to the migration algorithm, freeing the imaged section from all these artifacts due to the over-approximated positions of the sources. It must be emphasized that the quality of the final results mainly depends on the ability to separate multiples from primaries. The proposed approach, thanks to its ability to cope with any acquisition geometry, can be applied to any marine acquisition geometry, while any imaging technique can be exploited after the proposed source geometry transform. Acknowledgements. The authors would like to thank Francesco Miranda (eni) for fruitful discussions and valuable suggestions. References A.J. Berkhout, and D.J. Verschurr, 2006, Imaging of multiple reflections: GEOPHYSICS, VOL. 71, NO. 4 (July- August 2006), P.SI209-SI220, 19FIGS. N. Bienati, P. Mazzucchelli, and M. Codazzi, 2012, 3D-SRME Antialiasing in the Multiple Contribution Gather Domain: 74th EAGE Conference & Exhibition incorporating SPE EUROPEC 2012 Copenhagen, Denmark, 4-7 June 2012 B. Dragoset, E. Verschuur, I. Moore, R. Bisley, 2010, A perspective on 3D surface-related multiple elimination: GEOPHYSICS,VOL. 75, NO. 5 (SEPTEMBER-OCTOBER 2010); P. 75A245–75A261, 19 FIGS., 1TABLE. C. Fortini, V. Lipari, 2013, Imaging of Multiple reflections: 32° Convegno Nazionale GNGTS 2013 Sessione 3.1 K. Hokstad, and R. Sollie, 2005, Surface-Related Multiple Elimination Applied To Walkaway VSP Data: 67th Conference and Exhibition, EAGE, Extended Abstracts, I023. Z. Jiang, J. Sheng, J. Yu, G.T. Schuster, B.E. Hornby, 2007, Migration methods for imaging different-order multiples: Geophysical Prospecting, 2007, 55, 1-19. Fig. 3 – a) receiver mirror migration of the simulated raw data; b) receiver mirror migration of the data after adaptive subtraction of the estimated water-layer multiples with the WVSP acquisition geometry superimposed; c) double mirror migration of the first order water-layer multiples. Arrows and circles highlight cross-talk artifacts that corrupt raw data migration but have been attenuated in either primary reflections migration and first water-layer multiple migration.