Upside-down Rayleigh-Marchenko; a practical redatuming scheme for seabed seismic acquisitions

Ocean-bottom seismic plays a crucial role in resource exploration and monitoring. However, despite their undoubted potential, the use of coarse receiver geometries poses challenges to accurate wavefield redatuming. This in turn affects the quality of subsequent imaging and reservoir characterization products. We develop a reciprocal version of the Rayleigh-Marchenko (RM) method, called the upside-down RM method, in which all spatial integrals are performed over the (usually much better-sampled) source carpet; this results in a redatuming scheme that naturally accommodates irregular and sparse receiver geometries. Our method requires the availability of multicomponent receivers and either dual sources or a preprocessing step of model-based source deghosting and uses only the down-going component of the receiver-side wavefield; as such, it can be interpreted as a full-wavefield extension of the mirror migration method commonly used in seabed settings. Two synthetic examples are used to showcase the effectiveness of our method, starting from the ideal scenario of finely and regularly sampled source and receiver arrays and subsequently considering different levels of decimation for the receiver geometry. Migrated images as well as common-angle gathers reveal that our method can be used to produce structural and amplitude-friendly imaging outputs with minimal data preprocessing.