Searcher Seismic has completed the Laurabada Ultracube 3D reprocessing project offshore Papua New Guinea.
The Laurabada Ultracube project entailed the reprocessing of two open-file 3D datasets with a broadband deghosting and pre-stack depth migration sequence over what is highly sought-after acreage.
The Ultracube is split into two cubes: The Eastern cube is near-shore, shallow water whilst the Western cube is deep-water in the Gulf of Papua.
Joshua Thorp , geoscience manager for Searcher Seismic, said: “Source and receiver deghosting was applied in the reprocessing which significantly improves the low frequency content. For Laurabada East, this helps with the imaging below the fold belt as that is quite dispersive and attenuative with the seismic source. Similarly, on Laurabada West, there is multiple large carbonate bodies that are highly absorptive which is only penetrated by the low frequency signal.”
“The legacy processing only applied 2D SRME for the demultiple, whereas the reprocessing has used 3D GSMP/SRME from Western Geco. In the fold belt on Laurabada East this in particular helped with the complex diffracted multiples from the seabed that were contaminating the pre-Tertiary grabens. On Laurabada West there were complex peg leg multiples from the top carbonates which were modelled and subtracted effectively.”
“The legacy processing only used an isotropic PSTM workflow, whereas the reprocessing used an anisotropic TTI pre-stack depth migration. In Laurabada East, the PSDM workflow allowed for high resolution velocity modelling in the fold belt which improved the pre-Tertiary graben imaging and depthing. In Laurabada West, there was detailed carbonate velocity modelling which combined with the deghosting allowed for much improved resolution on the flanks and base of the carbonate pinnacles,” Thorp added.
The Laurabada West Ultracube 3D Reprocessing Survey comprises of approximately 770 km2 whilst the Laurabada East Ultracube 3D Reprocessing Survey covers some 1,020 km2. The Laurabada 3D reprocessing project complements Searcher’s existing 2D seismic coverage which currently stands at over 80,000 km, offshore Papua New Guinea.