We consider a generic 4C-2D geometry that consists of two parallel ocean bottom cables (OBCs) 2.5 km apart. These cables can be shot in-line and processed as separate 2D lines. If additional source lines are added perpendicular to the OBCs, a 3D survey can be acquired. However, due to the distance between the cables, a substantial zero-fold area will be present between the receivers if depth specific converted wave binning is used. The preferred way to improve this geometry is the addition of a third OBC. If this is not possible, 3D binning results in additional high-fold 2D lines, which may be a desirable addition for interpretation purposes. However, comparison between additional P-P and P-S lines gained in this manner will be difficult, since they will not be spatially coincident.
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