Using Mirror Migration of OBS Data to Image the Deepwater Area of South China Sea

Abstract

Ocean bottom seismograph (OBS) is widely used in investigating deep crustal structure, which is characterized by a large amount of data information and abundant frequency components because of its multi-component acquisition. OBS is seldom used in deepwater oil and gas exploration and basin research due to the high cost. The complicated seismic wave field is caused by the complex seabed topography, basin and oil and gas structure in deepwater area, which increases the difficulty of image processing. In addition to reflection imaging, we utilize the multiple of OBS data to make accurate imaging and have achieved desirable results in a deep sea area in South China Sea in this paper. Firstly, the original P and Z components of OBS data are processed by wave field separation to obtain the upgoing wave filed and downgoing wave filed. Secondly, its image velocity filed is constructed. Finally, downgoing wave data is used to image (called mirror migration). Compared with conventional migration, the mirror migration can clearly image the seabed and provide better illumination for shallow layer below the seafloor in the case of sparse nodes, which is proved by the migration results of theoretical and real data in this paper.

Keywords

deepwater OBS data / mirroring migration / wave field separation

References

[1] Asakawa E., Mizohata S., Tsujimoto S., . Depth Imaging of OBS Reflection Data With Wave Field Separation, 2008, 9-12.

[2] Barr F. J. Dual-Sensor OBC Technology. The Leading Edge, 1997, 16(1): 45-52.

[3] Barr F. J., Sanders J. I. Attenuation of Water-Column Reverberations Using Pressure and Velocity Detectors in a Water-Bottom Cable, 1989

[4] Berkhout A. J., Verschuur D. J. Multiple Technology: Part 2, Migration of Multiple Reflections, 1994, 23-28.

[5] Chen F., Zhuang C., Zhou Y., . Calcareous Nannofossils and Foraminifera Biostratigraphy on the Northeastern Slope of the South China Sea and Variation in Sedimentation Rates. Earth Science, 2016, 41(3): 416-424.

[6] Dash R., Spence G., Hyndman R., . Wide-Area Imaging from OBS Multiples. Geophysics, 2009, 74(6): Q41-Q47.

[7] Grion S., Exley R., Manin M., . Mirror Imaging of OBS Data. First Break, 2007, 25(11): 37-42.

[8] Hoffe B. H., Lines L. R., Cary P. W. Applications of OBC Recording. The Leading Edge, 2000, 19(4): 382-391.

[9] Lecerf D., Boelle J. L., Lafram A., . WAZ Mirror Imaging with Nodes for Reservoir Monitoring—Dalia Pilot Test, 2010, 14-17.

[10] Lei C., Ren J. Y., Zhang J. Tectonic Province Divisions in the South China Sea: Implications for Basin Geodynamics. Earth Science, 2015, 40(4): 744-762.

[11] Pacal E. Seismic Imaging with Ocean-Bottom Nodes (OBN): New Acquisition Designs and the ATLANTIS 4C OBN Survey: [Dissertation], 2012.

[12] Reiter E. C., Toksöz M. N., Keho T. H., . Imaging with Deep-Water Multiples. Geophysics, 1991, 56(7): 1081-1086.

[13] Ronen S., Comeaux L., Miao X. G. Imaging Downgoing Waves from Ocean Bottom Stations, 2005, 6-11.

[14] Ronen S., Ratcliffe A., Nichols P., . Combined Ocean Bottom Stations and Surface Towed Seismic Streamers, 2003, 2-5.

[15] Verschuur D. J., Prein R. J. Multiple Removal Results from Delft University. The Leading Edge, 1999, 18(1): 86-91.

[16] Wang D. K., Liu H. S., Tong S. Y., . Ocean-Bottom Cable Data Multiple Suppression Based on Equipoise Pseudo-Multichannel Matching Filter. Applied Geophysics, 2015, 12(2): 179-186.

[17] Wang Y., Bale R., Grion S., . The Ups and Downs of Ocean-Bottom Seismic Processing: Applications of Wavefield Separation and up-down Deconvolution. The Leading Edge, 2010, 29(10): 1258-1265.

[18] Wang Y., Grion S., Bale R. Up-down Deconvolution in the Presence of Subsurface Structure, 2010, 14-17.

[19] Wang Y., Grion S., Bale R. What Comes up must have Gone down: The Principle and Application of up-down Deconvolution for Multiple Attenuation of Ocean Bottom Data. CSEG Recorder, 2009, 34: 16-20.

[20] Yan Y., Brown R. J. The Suppression of Water-Column Multiples by Wavefield Separation and Cross-Correlation, 2001, 9-14.

[21] Youn O. K., Zhou H. W. Depth Imaging with Multiples. Geophysics, 2001, 66(1): 246-255.

[22] Zhong G. J., Liu D. M., Feng C. M., . Mirroring Pre-stack Time Migration Processing for OBS P-Wave Data. Journal of Tropical Oceanography., 2014, 33(3): 46-51.