Research paper Analysis of SRTM data as an aid to hydrocarbon exploration in a frontier area of the Amazonas Sedimentary Basin, northern Brazil Delano M. Ibanez a, * , Raimundo Almeida-Filho b , Fernando P. Miranda a a Petrobras Research and Development Center (CENPES), Av. Hor acio Macedo, 950, Cidade Universit aria, Ilha do Fund~ ao, Rio de Janeiro, Brazil b National Institute for Space Research-INPE, C. P. 515, S~ ao Jos e dos Campos, Brazil article info Article history: Received 9 September 2014 Received in revised form 11 December 2015 Accepted 23 March 2016 Available online 28 March 2016 Keywords: Morphostructural analysis Petroleum exploration SRTM DEM Amazonas basin abstract The Shuttle Radar Topography Mission (SRTM) provided an unprecedented source of space-borne topographic information that has shown to be of particular interest for studies in densely vegetated tropical areas, such as Central Amazonia. The digital elevation models produced in that region show subtle details of the terrain that usually appear blurred in conventional remote sensing images. Inter- pretation of an SRTM-derived drainage network and geomorphometric features revealed several drainage anomalies, which are possibly the surface expression of buried morphostructural features. Integration with geological and geophysical ancillary data strongly suggested that interpreted features constitute potential structural sites for hydrocarbon exploration. However, due to their inferred nature, the structures herein identified are not by themselves a justification for drilling. However, they do provide information for planning seismic surveys, thus reducing costs of the exploration campaigns, as well as minimizing potential environmental impacts of such an enterprise in areas of tropical rain forests. Despite the relatively small size of the study area, it is expected that procedures presented in this paper can be successfully applied throughout the approximately 1,000,000 km 2 of sedimentary basins in the Brazilian Amazonian region. © 2016 Elsevier Ltd. All rights reserved. 1. Introduction Remote sensing technology is nowadays a well-accepted auxil- iary tool for hydrocarbon exploration in frontier areas, since it may provide relevant information for planning seismic surveys, thus reducing costs of the exploration campaigns (e.g. Mello et al., 1996; Mitra, 2011), and minimizing potential environmental impacts of such an enterprise. The use of this technology in low-relief sedi- mentary basins aims at identifying subtle surface expressions of buried structural features that may constitute possible prospecting sites. The term low-relief basin refers here to a sedimentary area, whose stratigraphic and structural features are completely buried by mostly undeformed younger sedimentary units and soils, in addition to the vegetation cover. Under such physiographical conditions, surface expressions of buried structures may be denoted by the local organization of drainage network. The expected arrangement in low relief basins filled with a flat-lying sedimentary section is the dendritic pattern, characterized by irregular drainage branching, with tributaries joining main streams at different angles (Howard, 1967). However, as recognized by many authors in diverse climatic and surface conditions (e.g. Howard, 1965; Miranda and Boa Hora, 1986; Deffontaines and Chorowicz, 1991; Berger, 1994; Raymond et al., 1994; Chauvaud and Delfaud, 2002; Araújo et al., 2005; Ollarves et al., 2006; Almeida-Filho et al., 2010; Burrato et al., 2012; Terri- zzano et al., 2014), drainage analysis may indicate the presence of buried geological features, which are suggested by specific anom- alous patterns relative to the regional network. Therefore, stream alignment, or rectilinear stream segments, may be interpreted as the surface expression of buried faults and fractures. Furthermore, radial and annular drainage patterns, or a combination of them, are of special interest, since they may be associated with subtle surface expressions of buried domal structures that constitute potential hydrocarbon structural traps. The studied area is situated in Central Amazonia, which is unique in terms of general lack of outcrops, extensive rain forest and cloud cover, as well as a generally flat topography. Thus, the application of traditional geomorphological mapping is time * Corresponding author. E-mail addresses: dibanez@usp.br (D.M. Ibanez), rai@dsr.inpe.br (R. Almeida-Filho), fmiranda@petrobras.com.br (F.P. Miranda). Contents lists available at ScienceDirect Marine and Petroleum Geology journal homepage: www.elsevier.com/locate/marpetgeo http://dx.doi.org/10.1016/j.marpetgeo.2016.03.024 0264-8172/© 2016 Elsevier Ltd. All rights reserved. Marine and Petroleum Geology 73 (2016) 528e538