Abstract

In areas where 3-D is required to bring out subsurface features extending from shallow basin margins (100-400 m) to deep basinal part (1000 to 3000 m), finalizing the 3-D seismic data acquisition geometries remains a problem for the field Geophysicists. If the geometry is focused on shallow prospects in basin margin side, the offsets are inadequate to illuminate the deeper prospects towards basinal part. If the geometry is focused at deeper parts, then majority of larger offsets are not required in basin margin and these unwanted larger offsets are muted at the time of processing and again few smaller offsets are left with the processor which are inadequate to properly resolve the thin pinching sand layers in basin margin. The problem is further complicated if limited field resources are required to be optimized. In India, tackling this problem assumes greater importance under New Exploration Licensing Policy (NELP) regime where operator has limited allotted time to acquire data in both shallow and deeper prospects in single project.