West Mediterranean Sea | SLB

West Mediterranean Sea

Reprocessed seismic data from offshore Spain

We have recently completed reprocessing of 6,563 km of 2D data offshore Spain in the West Mediterranean Sea.  Our reprocessing workflow included a modern 2D isotropic prestack time migration (PSTM) and enhanced demultiple technique.

The reprocessed data offers increased resolution and improved imaging over the Valencia Trough, around the Balearic Islands, and into the Provincial basin. It presents a unique opportunity to map the behavior and distribution of the Messinian evaporites on a large regional scale—essential for any processing and imaging data quality.

 

Available now: AVO-ready products and PSTM volumes

A basin modeling study of the reprocessed survey has enabled better interpretation of the subsalt intervals and fault units due to enhanced velocity analyses and multiple algorithms. The updated data has pointed to some hydrocarbon plays. As part of the effort, four levels of hydrocarbon plays were observed:

  • Post-rift postsalt—Ebro group with biogenic gas expected within clastic turbidite deposits in the Plio-Pleistocene
  • Post-rift presalt—San Carlos group with Deltatic/turbidites deposits in the Miocene age
  • Synrift—basal tertiary group with Deltatic/canyon sands in the Lower Oligocene
  • Proven prerift with carbonate buildups in the Mesozoic

The proven hydrocarbon reservoirs on the western Mediterranean are allocated to the Mesozoic age and represented by Upper Jurassic limestones and Lower Cretaceous shallow marine carbonates (limestones and dolostones). Potential leads of Mesozoic age were mapped on the reprocessed data and clastic Tertiary reservoirs have been justified and mapped.

Map of 2012 reprocessed 2D data offshore Spain survey map.

Geophysical challenges include Messinian shallow evaporites, a rugose water bottom, multiple contamination, and complex subsalt imaging

Comparsion of legacy and reprocessed seismic data for offshore Spain survey.
Seismic comparison vintage migration (top) versus reprocessed 2012 migration (bottom). Our reprocessing workflow resulted in enhanced demultiple, improved signal-to-noise ratio, and improved imaging.

Key highlights

  •  6,563 km of 2D isotropic PSTM
  • Enhanced demultiple using 2D surface-related multiple elimination (SRME)
  • Improved signal-to-noise ratio
  • Improved imaging

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