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Efficient Amplitude Encoded Least Square RTM Using Cosine Basis
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, 76th EAGE Conference and Exhibition 2014, Jun 2014, Volume 2014, p.1 - 5
Abstract
Summary
Least square reverse time migration (LSRTM) provides better imaging result than conventional migration methods but the computational cost of common shot LSRTM is high. The phase encoding technique is usually adopted to enhance the efficiency. In this paper, the orthogonal cosine basis is used as encoding function which is an amplitude encoding function. And it is more convenient to implement and more efficient than phase encoding functions in time domain LSRTM. The reference distance plays an important role in suppressing crosstalk noise. We develop two schemes called fixed-distance scheme and shifting-distance scheme during iterations. In the first scheme, the reference distance is fixed during iterations. In the second scheme, the reference distance is decreasing during iterations to obtain higher efficiency gain. And since the crosstalk noise is moving as the reference distance changes, the stack of gradients during iterations can suppress the crosstalk noise. Numerical examples demonstrate the feasibility of this method.
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