Fast Least-Squares Reverse Time Migration of OBN Down-Going Multiples

Nowadays the ocean bottom node (OBN) acquisition is widely used in oil and gas resource exploration seismic monitoring. Conventional imaging algorithms of OBN data mainly focus on processing up-going primaries down-going first-order multiples. Up-going multiples higher-order are generally regarded as noise should be eliminated or ignored conventional migration methods. However, carry abundant information about subsurface structures where cannot achieve. To take full advantage multiples, we propose a method using all-order And then least-squares optimization algorithm to suppress crosstalks. Finally, phase-encoding-based developed cut down computational cost by blending several common receiver gathers together random time delays polarity reversals. Numerical experiments complex Marmousi model illustrate that approach can enlarge area evidently, reduce effectively, enhance image quality suppressing crosstalks improving resolution.