Geology

PGS basin study work confirms that presalt exploration in the Santos basin could yield further significant discoveries. Many independent oil companies also recognize this potential and the need for high-quality seismic data for upcoming licensing rounds to mitigate exploration risk. 

Derisking is made possible with this rejuvenated Santos Vision product which delivers broadband data with superior bandwidth in the presalt reservoir.

The Santos Basin has seen oil and gas production since the 1970s, and remains active as new technology and play concepts reveal far more potential than was originally envisioned. The Brazil presalt play fairway is a focus for many companies. Proven reservoir potential is present within the micro-biolite and coquinas formations/structures, which contain large hydrocarbon accumulations. This play fairway continues to develop through unitization and bid rounds.

The reservoir targets are localized in presalt carbonate build-ups underneath the basal anhydrite of heterogeneously layered evaporate sequences and interbedded with volcanic rocks. This challenging geological setting requires innovative seismic solutions.  PGS has provided these solutions with a excellent process for velocity model building and our unique implementation of Full Waveform Inversion (FWI) utilizing the full wavefield. This FWI pushed deeper than ever before, obtaining robust velocity updates in the presalt section and throughout the entire 34 000 sq. km area.

Santos Vision top salt3D relief of the top salt in the Santos Basin, Brazil.

The figure above shows 3D relief of the top of the Layered Evaporite Sequence (LES or “salt”) illustrating the major tectono-stratigraphic domains along the San Paulo Plateau (Santos Basin, Brazil). The Plateau is bound to the west by a prominent half-graben that downthrows the LES by up to 3 500 m and reveals shallow active salt diapirs (Merluza Graben). At the Albian Cap in the northwestern (inboard) sector of the plateau the Aptian LES is largely absent and restricted to remaining salt roller structures under counter-regional rollover faults. The outboard mini basin domain comprises predominantly grounded (welded) mini basins separated by up to 4 000 m thick salt walls and diapirs, which reveal complex internal structural geometries due to the seismic reflectivity of the component evaporite layers. Towards the distal sector of the plateau (southeast) the mini basins are gradually transient into the fold and thrust belt defined by well imaged layering of the LES reduced to its original thickness.