Processing and imaging of towed-streamer electromagnetic data with synthetic aperture method
Michael S. Zhdanov and Xiaolei Tu
Journal name: First Break
Issue: Vol 37, No 12, December 2019 pp. 51 - 54
Special topic: Data Processing
Info: Article, PDF ( 1.37Mb )
Price: € 30
The synthetic aperture (SA) method is one of the key techniques in remote sensing using radio frequency signals. Introduced in the early 1950s, Synthetic Aperture Radar, or SAR revolutionized reconnaissance surveying using radio and microwave signals. The key idea of the SAR is based on considering the entire flight path of airborne or spaceborne platform as a huge synthetic antenna, and on processing simultaneously all signals collected along this path. As a result, the clarity and resolution of the images produced by SAR can be improved dramatically. Over the last few years the SA concept has also been extended to the case of a low-frequency electromagnetic field used in marine geophysical exploration (e.g., Fan et al., 2010, 2012; Knaak et al., 2013; Mattsson and Engelmark, 2013; Yoon and Zhdanov, 2015). Marine controlled-source electromagnetic (CSEM) methods provide a valuable derisking tool complementary to the seismic method (Constable and Srnka, 2007; MacGregor and Tomlinson, 2014). The conductivity model derived from CSEM data, when properly integrated with other geophysical data, helps to determine the hydrocarbon saturation and fluid properties of potential targets with reduced uncertainty (MacGregor et al., 2007; Gao et al., 2012). However, the interpretation of CSEM data is still a challenge, especially with the recent development of the towed-streamer EM survey system, which could produce a large volume of data covering a vast survey area in an efficient way (Du*, 2015; McKay et al., 2015; Constable et al., 2016). It usually takes several days or even weeks on supercomputers to run a full 3D inversion for such a large dataset (Zhdanov et al., 2014a, b). A fast processing technique for reconnaissance purposes is, therefore, required for fast imaging of the observed EM data. The concept of synthetic aperture provides a way of addressing this problem.