BPS, using the largest geochemical, geophysical and geological data set available for the Sergipe-Alagoas Basin, is currently performing an entirely new 3D PSM study of its deep-water area (Figure 1). The study will include all public data from the recently-discovered Upper-Cretaceous light oil and condensate accumulations and will benefit from the expertise of BPS’s exploration team for general G&G, geochemistry and PSM, as well as the latest developments in software (local grid refinement and seismic facies) and computing power. Thus, the study will provide state-of-the-art modeling, incorporating all available geological, geochemical, PVT, petrophysical, biostratigraphy and geophysical data in order to achieve a maximum-resolution and highly accurate 3D compositional model of this deep-water province. The resulting model will serve as a dynamic decision-making tool for potential M&As, exploration programs and well planning.

The petroliferous offshore portion of Sergipe-Alagoas Basin has attracted exploration efforts for oil and gas for a long time. It started with the first offshore discovery ever made in the Brazilian sedimentary basins with the drilling of the 1-SES-1-SES well (Guaricema Field) in the late 1960s. Recently, new giant discoveries have been made in the deep and ultra-deep-waters of the Sergipe Basin and these exploration successes proved the existence of multiple active petroleum systems in the province, naturally raising renewed interest among oil industry players.

These discoveries, which surpass two billion barrels of oil in place, are in close vicinity to several exploration blocks that will be offered or are planned to be offered in the upcoming bidding rounds to be held by the Brazilian National Petroleum Agency (ANP) (Fig. 1). The oils of these Upper Cretaceous turbidity reservoirs were analyzed through our proprietary Advanced Geochemistry Technology (AGT, e.g., QGC-MS-MS, QDA, CSIA-Bh and QEDA) and indicated that they were all sourced from marine-anoxic, organic-rich source rocks of the Albian-Cenomanian/Turonian age and, most importantly, the majority contained highly-mature, lacustrine-brackish light oil and condensates that were sourced by anoxic black shales of the Aptian-Barremian age. In addition, some oils contained abundant concentrations of plant-related biomarkers typical of Maastrichtian and Tertiary oils (Figure 1)

The study specifically addresses such complex oil-mixing questions by utilizing advanced geochemical methods, as well as PVT data. Special focus will be put on facies distribution of source rocks, carrier beds, reservoirs and seals, as partly determined by paleogeography, paleo-topography and locations and directions of sedimentary input, etc.

Spectrum performed a 16,340 linear kms of high-quality 2D PSTM and PSDM seismic data acquisition program in 2014 that covered key wells in the offshore areas of the Sergipe-Alagoas Basin, including all the recent deep-water discoveries such as the Barra, Poça Verde, Cume, Moita Bonita, Muriu and Farfan oil fields. It also reprocessed pre-existing seismic data in the northeastern part of the basin (Alagoas), where channel-fill sediment plays, rifted basin fill and faulted Paleozoic sediments still present good exploration opportunities (Figures 2-3).