Petroleum System Applied from Basin to Reservoir Scale: An Application for the Charge Timing of the Pre-Salt Cluster Area, Santos Basin, Brazil

Pontet, Matthieu
[email protected]

After several years of intense exploration combined with major discoveries in the Pre-Salt Cluster of the Santos Basin in Brazil, new challenges for basin modeling arise from the reservoir and development side. The development of the Sapinhoa field (formally Guará prospect – 2,100 Mbbl reserves) in the BMS-9 concession required the understanding of the chromatographic composition of heavier (paraffinic) components then the fluid composition origin.

Advanced fluid type characterization has been performed including geochemical analyses from crude oil and fluid inclusion studies. Biodegradation indications from 25-norhopane biomarker and multiple migration pulses recorded from fluid inclusions lead to a complex charging history.

This work presents the integration of these new data to tentatively refine the migration processes and determine more precisely the charge timing of the pre-salt reservoir. Both invasion percolation and Darcy migration were applied to calibrate the fluid quality of the Sapinhoa field on a 3D block using LGR (Local Grid Refinement). At least 2 migration events occurred resulting in the mixture of the first oil reservoired under biodegradation conditions with the latest oil filling the reservoir.

This charging history is compatible with the background from petroleum and basin modeling studies developed over the past years and presented during the 2012 Petroleum System Hedberg session. This work aimed to constrain the source-rock potential and the efficiency of the Pre-Salt Santos petroleum system. The sourcing from 2 lacustrine source-rocks has been established with quantification of the relative contribution from each and determination of the fetch area by source-rock tracking.

This study demonstrate the multi-scale potential of basin modeling as a tool for understanding, data integration and overall coherency check from regional to reservoir scale.

AAPG Search and Discovery Article #90166©2013 AAPG International Conference & Exhibition, Cartagena, Colombia, 8-11 September 2013