Method for imaging of targeted reflectors

Techniques are disclosed for performing time-lapse seismic monitor surveys with sparsely sampled monitor data sets. A more accurate 3D representation (e.g., image) of a target area (e.g., a hydrocarbon bearing subsurface reservoir) is constructed using the sparsely sampled monitor data set (11). The sparsely sampled monitor data set may be so limited that it alone is insufficient to generate an accurate 3D representation of the target area, but accuracy is achieved through use of certain external information (14). The external information may include information accurately identifying a shape of the seismic reflector(s) present in the target area. The shape may be predetermined from a fully sampled base survey, and used to enable an accurate 3D representation (12) of the target area to be later generated for a monitor survey using a sparsely sampled monitor data set.