PGS’ extensive dataset over Campos deepwater reveals new geological insights, resolving complex structures and key petroleum system elements in presalt and post-salt plays.

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Discoveries in the ultra-deep water have bolstered the prospectivity of this area, extending the proven working petroleum system. Seismic interpretation combined with QI analysis has led to the identification of numerous leads and prospects, outlining several presalt trends primed for exploration.

Campos Exploration Development

The Campos basin has been an exploration success in the post-salt for several decades. Inboard, on the presalt plateau, fields such as Marlim (1.7bnbbl) have produced vast quantities of oil from post-salt turbidite sand reservoirs, sealed by intraformational mudstones and shales. In the Campos deepwater area, exploration of the post-salt has encountered good reservoir-quality turbidite sands but finding hydrocarbons has proved challenging. Despite this, the attraction of a potential stacked target play combination with the presalt is substantial, resulting in an exploration focus extension to deepwater presalt plays.

Presalt exploration results in Campos deepwater are encouraging. Nearby discoveries prove a working petroleum system in the presalt, most notably Pão de Açúcar, which discovered 700 mmbbl of light oil and 3 Tcf of gas. In addition, wells 230 and 554 encountered oil along the inboard edge of the survey. Further east towards the outboard edge of the survey in the ultra-deep water, Urissane and Mairare discoveries confirm that this presalt petroleum system extends laterally through the entire Campos deepwater dataset.

The Campos Presalt Play

The main source rocks in the Campos Basin are Lower Cretaceous lacustrine calcareous black shales of the Lagoa Feia Group, with the main source kitchen situated within the exterior rift zone and additional smaller source kitchens extending to the north and north-east, separated by structural highs.

The target reservoirs of the presalt succession are lacustrine carbonate or siliceous microbialites and coquinas deposited during the rift/sag phase at the late Barremian to Aptian. Focused on structural highs and sealed by Aptian layered evaporites, these formations are easily recognized and mapped by their external geometries and internal seismic facies characteristics.

Complex salt geometries are characteristic of the Campos Basin, influenced by basin structure and morphology which can be divided into three main structural domains; presalt plateau, exterior rift zone, and outer basement step (see seismic image below), marking the transition from continental to oceanic crust.

Vertical KPSDM seismic section highlighting the different salt and tectonic domains: (1) presalt plateau, (2) exterior rift zone low and (3) outer basement step. Click to enlarge and use the zoom buttons on the bottom right. 

During the Late Cretaceous and Tertiary thermal subsidence of the basin and oceanward tilting caused gravity gliding of the post-salt carapace resulting in the development of salt rollers, Albian fold belt, and mini basins (see image below). The Campos deepwater dataset resolves imaging challenges typically incurred by such salt geometries.

Top of salt map illustrating the major salt tectonic domains (outlined by white dashed lines) and their displacement along a regional sinistral strike-slip fault (black dashed line). Cold colors represent deep, partially welded mini basins.

Exploration Shift Towards Outboard: Assessing an Emerging Play

The recent presalt discoveries present a new challenge: to determine how far outboard hydrocarbon prospectivity extends. Several models of the structural framework of the distal portion of the basin have been established, and its implications for the petroleum system remain unsettled. For example, the transition from continental to oceanic crust, the presence of hyper-extended continental crust, wedging of the syn-rift sequence, or even exhumed mantle has generated many interpretations.

Revealing Prospectivity with PGS Data

Overall, the Campos Basin holds significant potential for exploration and production, and continued investment will likely unveil new discoveries in the years to come. The exploration success within the Campos deepwater region provides confidence in the group of undrilled prospects mapped on the seismic. These carbonate build-ups and microbial platforms display strong AVO responses, and are used to plot and nominate license blocks through the ANP for future Permanent Offer Rounds. 


Contact a PGS expert

Please contact a member of our Brazil team for more information.