South Atlantic Basins Virtual Research Symposium: Offshore Basins of Argentina, Brazil and Uruguay: the Next Exploration Frontier

Authors: Christian Heine, Shell South Atlantic Rift Dynamics: Insights from Plate Models, Regional Observations, and Numerical Models. A symposium paper presented by Christian Heine on 3 December 2020 as part of the South Atlantic Basins Virtual Research Symposium.

Authors: Juan Lovecchio (presenter), Sébastien Rohais, Philippe Joseph, Néstor Bolatti, Víctor A. Ramos, YPF The opening of the South Atlantic in the Early Cretaceous was the final stage of the complex Mesozoic rifting history of SW Gondwana. In this contribution we reassess the chronology of Mesozoic basin formation in southern South America (Argentina, Uruguay, southern Brazil) and its African conjugate and integrate it into the long-term breakup history of SW Gondwana. Triassic rifting, triggered by an absolute displacement of Gondwana to the NE and counter-clockwise rotation, is characterized by intracontinental rifting in Africa (Karoo I phase) and retro-arc extension on the SW-margin of Gondwana.In the Early Jurassic, the Karoo plume triggered rifting in Eastern Africa, producing the Karoo II basins and the Colorado and Salado basins on the Argentinean shelf. The East African rifting ultimately lead to breakup of Eastern from Western Gondwana in the Middle Jurassic. In the Patagonian retro-arc, the Austral-Malvinas and other basins formed in association with the synextensional emplacement of the Chon Aike magmatic province. In the Late Jurassic the Rocas Verdes back-arc basin opened in southern Patagonia, while oblique rifting in the core of the Late Paleozoic Gondwanides orogen produced the Outeniqua and Rawson/Valdés basins. The South Atlantic Rift initiated in the mid Valanginian (Early Cretaceous), with diachronous rifting starting in the previously thinned Rawson/Valdés-Outeniqua segment progressing northwards. North of the Colorado-Cape fracture zones, rifting and profuse SDR emplacement throughout the Late Valanginian-Hauterivian moved progressively to the north, along different rift segments separated by fracture zones and producing strongly asymmetric conjugate volcanic margins. Bio: Juan Pablo Lovecchio, YPF Juan Pablo is geologist graduated from the Universidad Nacional de Cordoba. He holds a Master's degree in Petroleum Geoscience from the IFP School, France, and a PhD from the Universidad de Buenos Aires and Sorbonne University, Paris. He has 12 years of experience in the industry. He started his career in Pluspetrol (2008-2010) and Total (2011), he then joined YPF in 2012 where he currently is Senior Exploration Geologist in Buenos Aires, Argentina, responsible for regional geology, and play and project assessment. He is an active member of several professional Associations and currently he is President of the AAGGP (Argentine Association of Petroleum Geologists and Geophysicists), Secretary of AAPG Latin America & Caribbean Region, and AGA YPF Delegate.

Authors: Marco Urdaneta (presenter), Sarah Meyer, Paul Mann, Conjugate Basins, Tectonic, and Hydrocarbons (CBTH) Based on several decades of shelf, slope and deepwater exploration on the South Atlantic rifted-passive margins, volcanic rifted margins exhibit less hydrocarbon potential than non-volcanic ones because the massive volcanic events can bury or over mature source rocks formed during the rift phase. The primary characteristic of volcanic margins are seaward-dipping reflectors, or “SDRs”that are defined as seaward-inclined, packages of igneous crust that underlie the transition from continental to oceanic crust. On the conjugate margins of South America and west Africa, many previous deep-penetration, seismic reflection and refraction studies have shown SDR belts of Barremian-Aptian age range that width from 91 to 117 km and in thickness from 10 to 20 km. The composition of SDRs where known from deep drilling on analogous volcanic margins can vary with mixtures of stratiform, subaerial volcanic flows separated by volcaniclastic units and non-volcanic marine and non-marine sedimentary units. Due to heterogeneity of SDRs, the Bouguer anomaly alone is not revealing for their mapping at regional scales. In this presentation, we describe a new method of using the total horizontal gradient of the Bouguer gravity anomaly to detect the sloping or faulted edges of SDRs. We have applied this method to the conjugate margins of the Pelotas and Punta del Este basins of southern South Atlantic in southern Brazil and Uruguay and the Walvis, Luderitz, and Orange basins of Namibia in West Africa. We compare the results from the gravity method to a compilation of deep-penetration seismic data to resolve the updip, downdip margins of the volcanic and non-volcanic margins. Our gravity results predict well the edges of the volcanic margin with errors of 10-20 km. We also compare the gravity results to magnetic mapping which on its own is not diagnostic - but offers some support of the gravity results. Bio: b>Marco Urdaneta, Conjugate Basins, Tectonic, and Hydrocarbons (CBTH) Marco is a Geology student at the University of Houston, where also works as Student Researcher at the CBTH Consortium, maintaining geological database and presenting research topic on SDR’s.

Authors: Renato Darros de Matos, Independent Researcher and Consultant Geodynamics of Rifting and Plumes During the South Atlantic Opening: a feedback System?. A symposium paper presented by Renato Darros de Matos on 3 December 2020 as part of the South Atlantic Basins Virtual Research Symposium. Bio: Renato Darros de Matos, Guarini Services Renato is geologist graduated from the Universidade de Brasília, Brazil (1979) and holds a PhD from Cornell University (1992). He has 40 years of professional experience, which includes 21 years at Petrobras, 4 years at academia (UFRN) as researcher, founder of Flamoil Services, E&P Director of Potioleo, Aurizonia and Imetame Energia (small independent oil companies); Coordinator and first President of ABPIP (Brazilian Independent Petroleum Producers Association); Exploration Manager of Petrobras International in Libya and Turkey; Management Director of the first board of the government controlled PPSA (Pré-Sal Petróleo S.A.). Currently, he is Director and Senior E&P Consultant at Guarini Services, Natal and Rio de Janeiro, Brazil. Renato is a member of AAPG, ABGP and SBGf.

Authors: Sverre Planke, Volcanic Basin Petroleum Research (VBPR), University of Oslo Structure and Development of Atlantic Volcanic Margins Constrained by Scientific Drilling. A symposium paper presented by Sverre Planke on 3 December 2020 as part of the South Atlantic Basins Virtual Research Symposium. Bio: Sverre Planke, Volcanic Basin Petroleum Research (VBPR) Sverre holds a MSc from the University of Utah and a PhD from the University of Oslo, Norway. With 30 years of experience in the industry, he is CEO at Volcanic Basin Petroleum Research AS (VBPR) and Professor at the University of Oslo, Norway (part time). Sverre is a member of AAPG, SEG, NGF, EGU and EAGE.

Authors: Patricia de Lugão (presenter), Eric Corrêa, Berthold Kriegshäuser, Strataimage Consultoria Ltda; Dallas Sherman, Frontier Geosciences Inc; Steve Constable, Institute of Geophysics and Planetary Physics, Scripps Institution of Oceanography, University of California San Diego The objective of this study was to characterize the background geology and electrical conductivity structure of the Punta Del Este Basin prior to continued exploration using the marine magnetotelluric (MMT) method. Data were collected at 165 sites along five profiles, with one 233 km-long line co-located with a low frequency seismic line and extending onto what should be oceanic crust in deep water (Constable and Sherman, 2014). The continental margin of Uruguay is segmented by the Río de la Plata Transfer System (RPTS) (Soto et al., 2011) with a NW–SE trend that interrupts and sinistrally displaces several geological and geophysical features, such as the seaward-dipping reflectors (SDRs) wedges, which are absent in the central sector of the Uruguayan offshore. The RPTS is limited by the Polonio High at north and was an important crustal structure during the Late Jurassic rifting and opening of the South Atlantic (Morales et al., 2017).The MMT data were inverted to produce two-dimensional (2D) resistivity models at depth that were interpolated into a 3D resistivity model revealing the structure of the RPTS. By analyzing the main features of the 3D model, three geoelectric limits were defined: top of rift at 30 Ohm.m, top of basement at 100 Ohm.m and crustal structures at 300 Ohm.m. At the basement level, the RPTS shows a NW-SE channel, marking two depocenters: at North, a deeper, NW-SE structure showing a sub-structure with NE-SW direction. At South, a channel with a clear NW-SE main trend. The crustal structures present three blocks and show the RPTS segmented at two zones of weakness with a clear relationship with the depocenters. Also, at the north side, block 3 is segmented by a NE-SW structure at the same level of the main weakness zones. Bio: Patricia de Lugão, Strataimage Consultoria Ltda Patricia holds a PhD in Geophysics from the University of Utah. She has 29 years of experience in the industry, and currently is Senior Geophysicist and Managing Partner at Strataimage Consultoria Ltda, Rio de Janeiro, Brazil, where is responsible for managing all aspects of geophysical projects. Previously, she worked in companies as Western Geophysical, Landmark and Schlumberger. Patricia is a member of SEG and EAGE.

Authors: Sebastian Vazquez Lucero (presenter), M.L. Gomez Dacal, F. Ibarra, C. Prezzi, M. Scheck-Wenderoth, J. Bott, H. Vizán, IGeBA – CONICET. The study area is located to the southeast of Buenos Aires Province between 36°- 39° S and 63°- 57° W and encompases the Claromecó Basin, the northernmost part of the Colorado Basin and the Sierras Australes.Several attempts have been made to study and analyse the onshore and offshore features of the Colorado and Claromecó Basins, due to its hydrocarbon potential. In this context, different hypotheses and mechanisms have been proposed for the genesis of these basins, as well as for the deformation of the Sierras Australes. The principal goal of this work is to contribute to a better knowledge of the sedimentary distribution of the Claromecó Basin and its thermal state. Secondarily, we aimed to shed light on the tectonic implications related to the crustal structure of the area. For these purposes, we developed a 3D lithospheric scale gravity forward and thermal model. For the model construction, we integrated: geological information, a global gravity model (EIGEN 6c4), published well data, seismic tomography data, pre-existing 3D density and thermal models of the Colorado basin (Autin et al., 2016) and published thermal properties.Our model allows to gain insight into both the thermal state and the thicknesses distribution of the Claromecó Basin sedimentary infill. We also propose a tentative location of the southernmost limit of the Rio de la Plata Craton, which contribute to the discussion of the geodynamic evolution of Claromecó basin, and the tectonic processes that affected the southwestern margin of Gondwana during Paleozoic times. Bio: Sebastián Emanuel Vazquez Lucero, IGeBA – CONICET Sebastián is a geologist from the University of Buenos Aires, and holds a MSc in Geology from the same university. Currently, he is a PhD student in Buenos Aires, and works as Researcher at CONICET.

Moderators: Hans Morten Bjornseth, Equinor; Juan Pablo Lovecchio, YPF Participants: Christian Heine, Shell; Renato Darros de Matos, Independent Researcher and Consultant; Sverre Planke, Volcanic Basin Petroleum Research (VBPR), University of Oslo; Patricia de Lugão, Strataimage Consultoria Ltda; Sebastian Vazquez Lucero, IGeBA – CONICET Conveners Hans Morten Bjornseth and Juan Pablo Lovecchio moderate a discussion with presenters, who answer questions and share final thoughts to conclude Session I, Volcanic Passive Margin Basins 1 – Tectonic Setting, at the South Atlantic Basins Virtual Research Symposium. Bios: Convener: Juan Pablo Lovecchio, YPF Juan Pablo is geologist graduated from the Universidad Nacional de Cordoba. He holds a Master's degree in Petroleum Geoscience from the IFP School, France, and a PhD from the Universidad de Buenos Aires and Sorbonne University, Paris. He has 12 years of experience in the industry. He started his career in Pluspetrol (2008-2010) and Total (2011), he then joined YPF in 2012 where he currently is Senior Exploration Geologist in Buenos Aires, Argentina, responsible for regional geology, and play and project assessment. Juan Pablo is an active member of several professional Associations and currently he is President of the AAGGP (Argentine Association of Petroleum Geologists and Geophysicists), Secretary of AAPG Latin America & Caribbean Region, and AGA YPF Delegate. Convener: Hans Morten Bjørnseth, Equinor Hans holds a MSc in Geology from the University of Tromsø, Norway. With 34 years of professional experience, he is currently Specialist Geologist at Equinor, Stavanger, Norway, where he works as project leader. His previous experience includes BP and Norwegian Petroleum Directorate. Christian Heine, Shell Renato Darros de Matos, Guarini Services Renato is geologist graduated from the Universidade de Brasília, Brazil (1979) and holds a PhD from Cornell University (1992). He has 40 years of professional experience, which includes 21 years at Petrobras, 4 years at academia (UFRN) as researcher, founder of Flamoil Services, E&P Director of Potioleo, Aurizonia and Imetame Energia (small independent oil companies); Coordinator and first President of ABPIP (Brazilian Independent Petroleum Producers Association); Exploration Manager of Petrobras International in Libya and Turkey; Management Director of the first board of the government controlled PPSA (Pré-Sal Petróleo S.A.). Currently, he is Director and Senior E&P Consultant at Guarini Services, Natal and Rio de Janeiro, Brazil. Renato is a member of AAPG, ABGP and SBGf. Sverre Planke, Volcanic Basin Petroleum Research (VBPR) Sverre holds a MSc from the University of Utah and a PhD from the University of Oslo, Norway. With 30 years of experience in the industry, he is CEO at Volcanic Basin Petroleum Research AS (VBPR) and Professor at the University of Oslo, Norway (part time). Sverre is a member of AAPG, SEG, NGF, EGU and EAGE. Patricia de Lugão, Strataimage Consultoria Ltda Patricia holds a PhD in Geophysics from the University of Utah. She has 29 years of experience in the industry, and currently is Senior Geophysicist and Managing Partner at Strataimage Consultoria Ltda, Rio de Janeiro, Brazil, where is responsible for managing all aspects of geophysical projects. Previously, she worked in companies as Western Geophysical, Landmark and Schlumberger. Patricia is a member of SEG and EAGE. Sebastián Emanuel Vazquez Lucero, IGeBA – CONICET Sebastián is a geologist from the University of Buenos Aires, and holds a MSc in Geology from the same university. Currently, he is a PhD student in Buenos Aires, and works as Researcher at CONICET.

Authors: Vitor Abreu, ACT Geosciences (presenter); Carlos Mikael Arnemann Batista, ANP; Sidnei Rostirolla, Consultant The Pelotas basin is a volcanic continental margin formed as a result of the opening of the South Atlantic Ocean during the Early Cretaceous. It is located offshore SE Brazil and Uruguay, limited by the Florianopolis High (Brazil) to the north and the Polonio Arch (Uruguay) to the south. It is marked by a volcanic basement dominated by Seaward Dipping Reflections (SDR’s) emplaced during the late phases of rifting and early drifting as an Initial Oceanic Crust. Bio: Vitor Abreu, ACT-GEO Vitor is an internationally recognized consultant, considered one of the world leaders in sequence stratigraphy and deep-water reservoirs, proposing deep-water models with strong impact in reservoir characterization. He received his PhD degree at Rice University (Houston). He has 35 years of experience in the oil industry in petroleum exploration, retired from ExxonMobil in 2016 and currently the owner of Abreu Consulting and Training – ACT-GEO. Vitor is Past-President of the Society of Sedimentary Geology (SEPM) and an Adjunct Professor at Rice University. More than 1000 students from around the globe have taken his short course on “Sequence Stratigraphy for Applied to Exploration” in the last 15 years. He is also one of the industry leaders on Sequence Stratigraphy and is the chief editor of SEPM’s book “Sequence Stratigraphy of Siliciclastic Systems”, which has sold almost 4000 copies since publication in 2010. He was the recipient of the AAPG’s Jules Braunstein Memorial Award and was appointed AAPG’s inaugural International Distinguished Instructor in 2006.

Authors: William Dickson, DIGs (Dickson International Geosciences) (presenter); Craig Schiefelbein, Geochemical Solutions International (GSI); Mark E. Odegard, GrizGeo LLC TWe review basins along Brazil's southeast margin, considering past, present and future exploration plays for the Sergipe, Campos and Santos basins with a comment on Pelotas where success yet awaits. Reasonable extrapolation begins by examining success elements (such as source and reservoir depositional environments, structural configuration, burial history, thermal regime) that show continuity. Changes to basin configurations from early- to late-rift to sag to drift are visible from inboard to distal basin regions, affecting both generation and charge stories. This reorders the success elements with some new and some disappearing. A new outboard play risk will be adequate burial for generation and to minimize risks of bio-degradation in the reservoir. Sources will inhabit the oldest sag to drift sections, possibly also interfingering with SDRs. CO2 flushing is a risk for carbonate reservoirs which will be more localized than in the main pre-salt region. Carbonates are likely also as isolated buildups atop volcanic highs associated with crustal spreading and hot spot features. Clastic reservoirs will improve where deepwater delivery systems fed basin floor fans or where deepwater turbidites were winnowed and reoriented into contourite stacks. We will traverse each basin going from same-same to same-but-different, illustrating each Phase with multi-disciplinary examples. We conclude with the admonition, based on our 2020 gravity imagery, that Pelotas holds surprises, beginning with evolution and makeup of its sediment floor. Which region will become the next super-super-giant or must Brazil adjust to just regular exploration success? Bio:d William Dickson, DIGs (Dickson Int'l Geosciences) William earned a bachelor’s degree from the University of Manitoba. He has more than 40 years of experience in the industry, working at majors and independents and, since 1998, at DIGs in Houston. He has worked frontier and producing basins around the Atlantic margins, EAME region, SE Asia & Canadian arctic and coordinated projects with subject matter experts across multiple disciplines. Peer-reviewed publications are primarily on petroleum systems analysis of Atlantic margin basins. Currently, as owner and VP Technology at DIGs, he is in charge of R&D, project coordination and fulfillment. William is member AAPG, EAGE, SEG, SPE and local societies in Houston, England, SE Asia & Australia.

Authors: Randall Etherington (presenter), Eric Newman, TGS Onshore, compressional structures are evident in the pre-rift rocks of the Sierras Australes. Similar compressional structures of the Sierras Australes can be traced with seismic data into the offshore. The individual rift basins along this margin initially formed from intracratonic rifting within the paleo-continent of Gondwana during the middle Mesozoic. The Colorado Basin that formed following north-west to south-east extension prior to the east/west extension that resulted in the opening of the South Atlantic can be clearly seen superimposed on the predominantly compressional pre-rift architecture. As evidenced by the Colorado Basin 2D survey, many structures have been eroded at the break-up unconformity level but the forelimbs and backlimbs of the folds are still present. This truncated stratigraphic relationship as well as the uneroded anticlines may act as hydrocarbon traps sourced by Permian, Carboniferous, and Early Cretaceous syn-rift source rocks. Exploration activities of the offshore Colorado Basin started in the 1970s. Only 26 exploration wells have been drilled on the northern margin (north of 47°S), with none in water depths greater than 100 meters and all located at least 15 km inboard from the continental shelf edge. These wells were drilled, mostly by major oil companies, without any commercial success. However, four wells with hydrocarbon shows confirmed syn-rift and Permian to Jurassic marine and lacustrine source. The pre-rift Structure Play of Paleozoic through Lower Cretaceous rocks is the primary play type of the Colorado Basin. Petroleum Systems include oil-generating source rocks proven in Permian - Jurassic pre-rift and Cretaceous syn-rift sediments. Reservoir rocks include pre-rift Permian-Jurassic, Cretaceous and Cenozoic sandstones. Bio: Randall Etherington, TGS-NOPEC Geophysical Company Randall earned a bachelor’s degree in Engineering from Utah State University, and a MSc in Geology from Brigham Young University. His more than 40 years of experience in the industry include several positions in companies as ExxonMobil, Chevron, Shell, Phillips, Devon, YPF-Regsol, Pennzoil, Cobalt, Murphy; Maersk, among others. Currently, he is Exploration Advisor at TGS-NOPEC Geophysical Company, where is responsible for geophysical interpretation and basin analysis. Randall is a member of AAPG and SEG.

Authors: Pablo Velázquez (presenter), Ethel Morales, Universidad de la República The genesis and evolution of the Uruguayan Continental Margin (UCM) are linked to the geological processes that resulted in the breakup of the Western Gondwana and the later opening of the Atlantic Ocean. The UCM is a typical volcanic passive margin segmented by the Rio de la Plata Transfer System. Three sedimentary basins are recognised in the UCM: the Uruguayan portion of Pelotas Basin, the Punta del Este Basin, and the Oriental del Plata Basin. The Oriental del Plata Basin is located in deep and ultra-deep waters of the Uruguayan offshore, being partly equivalent to the Argentine Basin on the Argentine margin. In this study, the stratigraphy of the Oriental del Plata Basin is characterized for the first time, through the interpretation of 2D seismic sections. The recognition of the main horizons or key surfaces on seismic profiles was attempted, which allowed us to divide the basin fills. Fourteen seismic units were identified in the Cretaceous/Cenozoic sedimentary succession based on reflection termination, sedimentary stacking pattern and seismic facies. The set of Cretaceous units presents a relatively constant thickness throughout the entire longitudinal section of the basin. While the set of Cenozoic units shows an important thickening at the foot-slope, corresponding mainly to the Oligocene-Miocene seismic units. Several interesting seismic features were identified in the Cretaceous/Cenozoic sedimentary succession of the basin, such as channels, contourites, normal faults (synthetic and antithetic), listric faults and related folding, mass transport deposits and olistostromes.

Authors: Eric Newman, NOPEC Geophysical (presenter); Randall Etherington, TGS Located along the South Atlantic Margin, the Argentine Basin has a tremendous potential for significant commercial oil resources as indicated by the strong participation and work commitments of the highly successful First Offshore Argentina Bid Round in April 2019. During this round, only Blocks from the Northern portion of Argentine Basin were available for bid, and seven of the fourteen available Blocks were signed. Yet the intriguing geology and hydrocarbon potential present in Northern Argentine Basin extends to the South, and the potential may even be greater. The elements for a working petroleum system appear to be present across the Argentine Basin with proven Aptian source rock found in the conjugant basins of Namibia and South Africa. In addition, younger rich marine source rocks of Albian and Turonian age could also be present though yet unproven. These strata have been mapped using long-offset, broadband seismic and the burial history is sufficient to be oil mature. Further, reservoir and trap elements appear to be present in syn-rift and post-rift architectures lending to both structural and stratigraphic traps. Possibly most prospective is the turbidite fan and channel plays of the Upper Cretaceous. In Southern Argentina Basin these channels are focused into ponded sub-basins by a protuberant basement high thus concentrating the sand deposits much as the Demerara Plateau has focused turbidite channels into the Guyana Basin. Bio: Eric Newman, TGS-NOPEC Geophysical Company Eric graduated as a Geophysical Engineer from the Colorado School of Mines. With 36 years of experiences, he is Geoscience Director – Latin America at TGS, Houston, where is responsible for basin evaluations and presentations to industry. His previous experience include working in companies as Amoco in Latin America and Far East, Union Texas Petroleum in Pakistan and South Atlantic New Ventures, Apache Corporation in China and Egypt, Burlington Resources in China, Peru and Colombia, Newfield Exploration in China and Indonesia, BHP Billiton in Central Africa and India, Maersk Oil in Brazil and Norway NV, Hess in South Atlantic New Ventures. Eric is a member of AAPG, SEG and HGS.

Authors: Karyna Rodriguez (presenter), Neil Hodgson, Searcher The largely underexplored West Malvinas Basin lies just to the east of the Austral Basin in southern Argentina, where up to 2 billion barrels of oil equivalent have been discovered to date. Source rock presence and quality is still considered to be one of the key risks in the Malvinas basin.Reprocessed 2D seismic data was integrated with conditioned well logs in a full petroleum systems evaluation together with a regional geological review, plate tectonics and magnetics/gravity data, allowing the definition of a synchronised sequence stratigraphic scheme unifying 8 basins.The main source rocks in the Malvinas Basin are considered to be Upper Cretaceous shales of the Lower Inoceramus Fm, with source potential also identified in the Early Cretaceous post-rift Springhill and Margas Verdes Formations and seismic observations, from reprocessed seismic data, strongly point to the syn-rift lacustrine shales in the Jurassic Tobifera Formation. Understanding the lateral distribution of lacustrine shales is key to unlocking the charge story. Data quality of reprocessed 2D seismic data allowed a detailed interpretation below the Base Cretaceous unconformity, enabling interpretation of the Jurassic source rock section. Shallow gas indicators in the Malvinas Basin provide proof of a working petroleum system. Their distribution was mapped within the basin using both traditional methods and a Machine Learning process. Indications of greater density of shallow anomalies can be attributed to a potential Jurassic syn-rift charge origin. By integrating the understanding from South African basins, there is greater confidence in the results from this study on the presence of a potential dual source working petroleum system, further addressing one of the key risks in the Malvinas Basin and increasing the chance of success in future exploration activities. Bio: Karyna Rodriguez, Searcher Karyna earned a BS and a MSc in Geology from the Oxford University and a MSc in Stratigraphy from the University College London. With 31 years of experience in the industry, Karyna is VP Global New Ventures at Searcher, UK, where she is responsible for developing and managing Searcher projects which support energy companies’ ongoing and future energy exploration campaigns. She previously worked in companies as British Gas, PEMEX, Apache, Pioneer. Her professional affiliations include AAPG, EAGE, PESGB, London Geological Society.

Moderator: Bruno Conti, ANCAP; Javier Hernández-Molina, Royal Holloway, University of London Participants: Vitor Abreu, ACT Geosciences; William Dickson, DIGs (Dickson International Geosciences); Randall Etherington, TGS; Eric Newman, NOPEC Geophysical; Karyna Rodriguez, Searcher Conveners Bruno Conti and Javier Hernández-Molina moderate a discussion with presenters, who answer questions and share final thoughts to conclude Session II, Volcanic Passive Margin Basins 2 – Basin Analysis, at the South Atlantic Basins Virtual Research Symposium. Bios: Convener: Bruno Conti, ANCAP Bruno is a geologist from the Universidad de la República, Uruguay, and holds a MSc in Geoscience from Universidade Estadual Paulista, Brazil. With 11 years of professional experience, he currently is Exploration Geologist at ANCAP, Montevideo, Uruguay, where is responsible for seismic interpretation, sequence stratigraphy and petroleum systems analysis of Uruguay sedimentary basins. Before ANCAP, he worked for 4 years in UME (Uruguay Minerals Exploration). Bruno is a member of AAPG. Convener: Javier Hernandez-Molina, Royal Holloway, University of London Javier holds a PhD from the University of Granada (1993). He is Professor in Sedimentary Geology at the Royal Holloway, University of London. Vitor Abreu, ACT-GEO Vitor is an internationally recognized consultant, considered one of the world leaders in sequence stratigraphy and deep-water reservoirs, proposing deep-water models with strong impact in reservoir characterization. He received his PhD degree at Rice University (Houston). He has 35 years of experience in the oil industry in petroleum exploration, retired from ExxonMobil in 2016 and currently the owner of Abreu Consulting and Training – ACT-GEO. Vitor is Past-President of the Society of Sedimentary Geology (SEPM) and an Adjunct Professor at Rice University. More than 1000 students from around the globe have taken his short course on “Sequence Stratigraphy for Applied to Exploration” in the last 15 years. He is also one of the industry leaders on Sequence Stratigraphy and is the chief editor of SEPM’s book “Sequence Stratigraphy of Siliciclastic Systems”, which has sold almost 4000 copies since publication in 2010. He was the recipient of the AAPG’s Jules Braunstein Memorial Award and was appointed AAPG’s inaugural International Distinguished Instructor in 2006. William Dickson, DIGs (Dickson Int'l Geosciences) William earned a bachelor’s degree from the University of Manitoba. He has more than 40 years of experience in the industry, working at majors and independents and, since 1998, at DIGs in Houston. He has worked frontier and producing basins around the Atlantic margins, EAME region, SE Asia & Canadian arctic and coordinated projects with subject matter experts across multiple disciplines. Peer-reviewed publications are primarily on petroleum systems analysis of Atlantic margin basins. Currently, as owner and VP Technology at DIGs, he is in charge of R&D, project coordination and fulfillment. William is member AAPG, EAGE, SEG, SPE and local societies in Houston, England, SE Asia & Australia. Randall Etherington, TGS-NOPEC Geophysical Company Randall earned a bachelor’s degree in Engineering from Utah State University, and a MSc in Geology from Brigham Young University. His more than 40 years of experience in the industry include several positions in companies as ExxonMobil, Chevron, Shell, Phillips, Devon, YPF-Regsol, Pennzoil, Cobalt, Murphy; Maersk, among others. Currently, he is Exploration Advisor at TGS-NOPEC Geophysical Company, where is responsible for geophysical interpretation and basin analysis. Randall is a member of AAPG and SEG. Eric Newman, TGS-NOPEC Geophysical Company Eric graduated as a Geophysical Engineer from the Colorado School of Mines. With 36 years of experiences, he is Geoscience Director – Latin America at TGS, Houston, where is responsible for basin evaluations and presentations to industry. His previous experience include working in companies as Amoco in Latin America and Far East, Union Texas Petroleum in Pakistan and South Atlantic New Ventures, Apache Corporation in China and Egypt, Burlington Resources in China, Peru and Colombia, Newfield Exploration in China and Indonesia, BHP Billiton in Central Africa and India, Maersk Oil in Brazil and Norway NV, Hess in South Atlantic New Ventures. Eric is a member of AAPG, SEG and HGS. Karyna Rodriguez, Searcher Karyna earned a BS and a MSc in Geology from the Oxford University and a MSc in Stratigraphy from the University College London. With 31 years of experience in the industry, Karyna is VP Global New Ventures at Searcher, UK, where she is responsible for developing and managing Searcher projects which support energy companies’ ongoing and future energy exploration campaigns. She previously worked in companies as British Gas, PEMEX, Apache, Pioneer. Her professional affiliations include AAPG, EAGE, PESGB, London Geological Society.

Authors: Pedro Victor Zalán, ZAG Consulting in Petroleum Exploration (presenter); Eric Newman, TGS The acquisition and interpretation of 3 long offset 2D seismic surveys in the southern part of the Campos Basin and in the whole of Santos Basin allowed the recognition of the southward extension of the External High beyond the EEZ. The External High is the most important feature of both basins because, being a >600 km continuous feature, it plays the role of main focusing high for both surrounding Internal and External Kitchens. It controls the location of the majority of the Pre-Salt and Post-Salt producing fields. Upon this newly mapped extension very large structural highs (> 1000 km2 of 4-way closure) were identified at the base of the salt beyond the EEZ. Recently shot 3D surveys confirmed the existence of such huge structures and allowed an unprecedented view of their complex deformation. For the first time, a glimpse into the highly complex deformation history of the last lapses of continental separation can be attained. Very strong strike-slip related positive and negative flower structures of great relief can be observed. A holistic view of the intensively broken, faulted, uplifted and twisted outer continental crust is displayed in accompanying figures. Amidst this intense deformation, very large structural closures occur, completely sealed by salt. Typical Pre-Salt reservoir seismic facies can be observed in the structures. Planar, parallel reflectors indicative of the carbonate ramp model of microbialite deposition and travertine cones/buildups related to hydrodynamically active syn-rift faults can be seen right beneath the base of salt. Another important feature revealed by the 3D surveys is the presence of thick, deep-seated grabens filled by sedimentary strata adjacent to such highs. Their existence is important as they may contain the so-needed source rocks of the External Kitchen. Bio: Pedro Victor Zalán, ZAG Consulting in Petroleum Exploration Pedro holds a MSc and a PhD from the Colorado School of Mines. With 42 years of experience in the industry, he is independent consultant in petroleum exploration at ZAG Consulting in Petroleum Exploration, in Rio de Janeiro. He worked for 34 years in Petrobras. Pedro is a member of AAPG and ABGP.

Authors: Francyne Bochi do Amarante, Universidade Federal do Rio Grande do Sul - Imperial College London (presenter); Christopher Aiden-Lee Jackson, Imperial College London; Leonardo Muniz Pichel, University of Bergen; Claiton Marlon dos Santos Scherer, Juliano Kuchle, Universidade Federal do Rio Grande do Sul Salt-bearing passive margin basins offshore SE Brazil have been and remain attractive for hydrocarbon exploration and production. In the Campos Basin, major reservoir types include post-salt turbidites, which are located in structural traps related to thin-skinned faulting above salt pillows and rollers. Classic models of gravity-driven salt tectonics commonly depict kinematically linked zones of deformation, characterised by updip extension and downdip contraction, separated by a weakly deformed zone associated with downdip translation above a relatively smooth base-salt surface. We use 2D and 3D seismic reflection and borehole data from the south-central Campos Basin to show that this does not adequately capture the styles of salt-detached gravity-driven deformation above relict, rift-related relief. We show that base-salt ramps can create local stress fields and complex structures in the translational zone, with these overprinting the regional, margin-scale patterns of deformation. These structures include c. 20-30 km wide ramp-syncline basins and contractional salt anticlines that were later extended and faulted. This multiphase deformation relates to changes in the volume and velocity of the salt crossing seaward-dipping base-salt ramps, with the most complex structures forming in response to translation of salt and overburden across two ramps. We show that salt-cored anticlines in the translational domain can create large traps that may contain post-salt turbidites. Later extensional faulting of these anticlines can provide conduits for oil migration from the underlying source rocks, as well as define reservoir compartments. Bio: Francyne Bochi do Amarante, Universidade Federal do Rio Grande do Sul, Imperial College London Francyne earned a BSc in Geology at Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Brazil; a MSc in Geosciences with focus on Stratigraphy and Sedimentology at UFRGS; and currently is a PhD Candidate in Geosciences with focus on Basin Analysis at UFRGS; she also is a Visiting Researcher at Imperial College London during her PhD researching salt tectonics. Her professional experience includes research projects funded by Shell and Petrobras at UFRGS.

Authors: Roberto A. Scasso, IGeBA-CONICET-Universidad de Buenos Aires (presenter), Ignacio H. Escapa, Rubén N. Cúneo, CONICET-Museo Paleontológico Egidio Feruglio; Jahandar Ramezani, Massachusetts Institute of Technology The Cañadón Asfalto Basin, in central Patagonia, shows a 3000 m thick succession of Jurassic and Cretaceous terrestrial sediments subdivided into three megasequences superbly exposed along the Chubut River canyon. The lower J1 megasequence (Hettangian to Late Bajocian) represents the incipient to juvenile stages of an extensional rift basin with high volcaniclastic input in fluvial and lacustrine environments. The seasonally wet, temperate/warm climate favored high productivity and biodiversity. During this stage tectonic relief controlled the accumulation of siliciclastic-dominated sediments in relatively small, fault-bounded depocenters, where later accumulated breccias, agglomerates and ignimbrites associated with an andesitic volcanism centered along the transfer zones. Further subsidence led to formation of microbial limestones capping and fringing upon the high-relief volcanic complexes, with thick, lacustrine limestones and black shales with interbedded basalts, in the deeper part of the depocenters. Different units in Megasequence J1 are separated by erosive or angular unconformities of limited extent, typical of high-relief volcanic settings and lacking of regional significance. The size and shape of the depocenters, the geological succession of depositional and volcanic events as well as the geometry of the sedimentary bodies between the Cañadón Asfalto and Pre-Salt are surprinsingly similar. Furthermore, the composition of the sediments (microbial/silicified limestones, volcaniclastics, black shales) of the J1 Megasequence closely resemble those of the sediments of the Pre-Salt basins and make the Cañadón Asfalto basin a remarkable surface example allowing direct observation of the sedimentary bodies, their lateral changes and complex geometric relations. Bio: Roberto A. Scasso, University of Buenos Aires - CONICET Roberto holds a PhD in Geological Sciences from the University of Buenos Aires. He is Professor of Sedimentology and Head Researcher at the University of Buenos Aires – CONICET, focused on Neuquén and Cañadón Asfalto basins. Roberto is a member of AGA (Argentine Geological Association), Argentine Association of Sedimentology, IAS and SEPM.

Authors: Lucas Cazelli Vasconcelos (presenter), Rene Rodrigues, Rio de Janeiro State University (UERJ) This study presents the organic geochemistry data obtained from the Upper Cretaceous interval in a well located on the southern Santos offshore Basin, Paraná, Brazil. The objectives of applying Total Organic Carbon Content, Pyrolysis, Stable Carbon Isotopes and Biomarkers analyses are to show their effectiveness as an alternative for high frequency correlation of the studied interval in the Santos Basin as well as analyze the characteristics of the organic matter present in relation to source-rock parameters, depositional environment and source of organic matter input. As shown by isopach maps (Assine et al., 2008), the well is located within the depocenter of the basin for the interested time-interval preserving a wide thick shale interval that can be mapped through seismic and geochemistry studies. It was possible to suggest the division of this interval in chemostratigraphic unities related to the sedimentary succession preestablished for the basin. The organic content of the shales indicates moderate to very good generation potential (fig. 1), with facies A and B at the beginning of the hydrocarbon generation window. The organic geochemistry data shows T/R cycles patterns as well as anoxic events related to Cenomanian and Turonian OEA 2 - backed up by isotopic data presented - also registered regionally and around the world. Therefore, it is shown the chemostratigraphic parameters as a possibly new regional sequence stratigraphic and correlation tool. Bio: Lucas Cazelli Vasconcelos, Rio de Janeiro State University Lucas is a geologist from Rio de Janeiro State University (UERJ). Currently, he is a Master’s student at UERJ’s post-graduate program with accepted project entitled “Organic Geochemestry and high resolution Chemostratigraphy: Upper Cretaceous of the Southern Santos Basin, Brasil”. He received a research grant for Geology Graduation Student at UERJ’s Stratigraphy and Paleontology Departament (2018/2019). Lucas is a member of SBG (Brazilian Geological Society).

Authors: Gustavo Camelo Acevedo, Ecopetrol Óleo e gas do Brasil (presenter); Diego Fernando Garcia Bautista, Ecopetrol; João Graciano Mendonça Filho, Universidade Federal do Rio de Janeiro The Campos offshore basin covers an area of about 100,000 km2 in the southeastern Brazilian continental margin. It is the second largest Brazilian oil and gas producer basin. Reservoirs are represented by Aptian carbonates and siliciclastic rocks ranging from Upper Cretaceous to Miocene. The main source rocks were deposited in lacustrine, alkaline waters under anoxic conditions with variable salinity, ranging from brackish to saline represented by the Lagoa Feia Formation. Such rocks are characterized by calcareous black shales rich in bacterial and algal-derived type I kerogen, up to 9% TOC (Trindade et al., 1995). Several geochemical, biostratigraphic and palaeoenvironmental studies in the Campos basin (Dias-Brito, 1982; Mello et al., 1989), suggested the presence of anoxic events, favorable for the deposition of organic – rich sediments, in a few mid Cretaceous sections of the South Atlantic margin. The organic matter (OM) content in the Albian – Turonian sediments was studied in two wells in order to describe the organic facies characteristics, depositional paleoenvironments and thermal maturity. Furthermore, the hydrocarbon generation of these kerogens was appraised as a potential source rock for the post-salt petroleum systems in restricted areas of the basin. Upper Cretaceous source rocks sourced most of the hydrocarbon’s accumulations in Trinidad and Tobago, Venezuela, Ecuador, Peru and Colombia (Talukdar et al., 1994). Extensive areas of effective Cretaceous source rocks are widespread in South America (Daswood & Abbots, 1990; Mora, 2000; Maceralli, 1998; Suhas et al., 1994). Bio: Gustavo Andres Camelo Acevedo, Ecopetrol Brasil Gustavo holds a MSc from the Universidade Federal do Rio de Janeiro. With 5 years of experience in the industry, he is Exploration Geologist at Ecopetrol Brasil, in Rio de Janeiro, where he elaborates multi 1D, 2D and 3D basin and petroleum systems models with the aim of evaluate petroleum charge effectiveness through the study of oil generation, migration and accumulation in different basins along the Brazilian continental margin; nowadays he focuses in the Pre-salt of Campos and Santos Basins. He also performs source rock potential evaluation based in geochemical and seismic data; regional analysis and evaluation of exploration opportunities (blocks and prospects) to Ecopetrol Brasil including the analysis of regional tectonics and structural geology. Gustavo is a member of AAPG, ALAGO, EAFE and SPWLA.

Authors: Adriana Henao (presenter), Egberto Pereira, Rio de Janeiro State University (UERJ) Stratigraphic and sedimentological modeling is a valuable tool for testing the parameters of the depositional process of sedimentary rocks. The present study on the tectono-estratigraphic evolution of the southwestern Santos Basin aims to show the geological context recorded in the Cenozoic of that basin regarding the rate of subsidence and the anomalous behavior of the relative sea level curve. The Cenozoic-Paleocene interval in the basin is mainly controlled by tectonic events in the continental region near to the basin, associated with the evolution of Serra do Mar. These events may explain the anomalous sedimentation recorded in this period, producing a sedimentary stack that generates a discrepancy between the coastal onlap curve and the behavior of the global eustatic level curve, in a condition of constant subsidence. The Dionisos modeling software allowed to test the role of the parameters in the sedimentary process in the Santos basin, by calculating possible deposition scenarios for the platform between 66 and 56 million years. A variety of scenarios were simulated, but only six are explored in this project. The main objective was to understand the controlling parameters of the formation and evolution of this system, considering the relative variations in sea level, sedimentary input, subsidence with a methodological approach that includes the seismic stratigraphic analysis of the seismic lines, chronostratigraphic data and lithological samples of 20 exploratory wells available, and the construction of 2D and 3D stratigraphic models. The scenario two reproduces the geometry observed on seismic section and allow to obtain the parameters that controls the sedimentation considering the techno-sedimentary evolution of the study area. The simulations for scenario two were carried out using the forward subsidence modeling method, with an average sedimentary input of 6325 Km3/Ma and river discharge of 3000 m3/s by placing three sources of input. From the final stratigraphic model in scenario 2, it was possible to estimate the temporal and spatial variation of accommodation, subsidence, sediment input, fluvial discharge, see level and migration of sedimentary sources that controlled the tecto-stratigraphic framework to the southwestern Santos Brasil. Bio: Adriana Henao, Rio de Janeiro State University Adriana graduated from Rio de Janeiro State University (UERJ). With 10 years of experience in the industry, she is Research and Associate Professor at America University, in Bogota, Colombia, where she teaches Geology, Petroleum Geology and Environment Sediments. Prior to being a Professor, Adriana worked as Exploration Geologist at GranTierra Energy. Adriana is a member of EAGE and SPE.

Moderators: Sylvia Anjos, Petrobras; Antonio Velásquez, Ecopetrol Brasil Participants: Pedro Victor Zalán, ZAG Consulting in Petroleum Exploration; Francyne Bochi do Amarante, Universidade Federal do Rio Grande do Sul - Imperial College London; Roberto A. Scasso, IGeBA-CONICET-Universidad de Buenos Aires; Lucas Cazelli Vasconcelos, Rio de Janeiro State University (UERJ); Gustavo Camelo Acevedo, Ecopetrol Óleo e gas do Brasil; Adriana Henao, Rio de Janeiro State University (UERJ) Conveners Sylvia Anjos and Antonio Velásquez moderate a discussion with presenters, who answer questions and share final thoughts to conclude Session III, Post-Salt and Pre-Salt Basins, at the South Atlantic Basins Virtual Research Symposium. Bios: Convener: Sylvia Anjos, Petrobras Sylvia holds a bachelor’s degree in geology from the Federal University of Rio de Janeiro and a master’s and a PhD in geology from the University of Illinois in the United States. Anjos has worked in the energy industry since 1979 and has dedicated her years of service to Petrobras in Rio de Janeiro. She served as manager of Stratigraphy, Sedimentology, Petrology and Biostratigraphy and manager of Rock Technologies at the Petrobras Research Center, then moved to Petrobras Exploration in 2005. She started as manager of the Petroleum Systems Modelling before being named general manager of geology for Petrobras Exploration, a position she held for 10 years. From 2016-2019 Anjos served as deputy general manager for the Libra Joint Project Team, representing Petrobras and overseeing applied technologies projects for the Libra field in the Brazilian pre-salt. Currently, she works as Geoscience and Engineering Business Advisor. Sylvia was founding member of the Brazilian Association of Petroleum Geologists (ABGP) and served two terms as president. She has been an active member of AAPG since 2001 and served as Latin America and Caribbean Region president from 2017-2019. Since 2018, she has served as member and co-founder of the Diversity Committee at the Brazilian Petroleum Institute (IBP). Convener: Antonio Velásquez, Ecopetrol Brasil Antonio obtained his Bachelor’s and Master’s degrees in Geology from the National University of Colombia. Also, earned a Master’s degree in Geophysics and Seismology form the Colorado School of Mines. With 15 years of experience in the industry, he started out his career in Ecopetrol and has been working continuously in different roles in exploration and as a Professor at National University of Colombia. Currently, he is Exploration Assets Manager at Ecopetrol Brazil, where he leads exploration efforts of Ecopetrol in offshore Brazil, including Ecuatorial Margin, Santos Presalt blocks and new bidding rounds. He is an active member of AAPG, EAGE and ACGGP. Pedro Victor Zalán, ZAG Consulting in Petroleum Exploration Pedro holds a MSc and a PhD from the Colorado School of Mines. With 42 years of experience in the industry, he is independent consultant in petroleum exploration at ZAG Consulting in Petroleum Exploration, in Rio de Janeiro. He worked for 34 years in Petrobras. Pedro is a member of AAPG and ABGP. Francyne Bochi do Amarante, Universidade Federal do Rio Grande do Sul, Imperial College London Francyne earned a BSc in Geology at Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Brazil; a MSc in Geosciences with focus on Stratigraphy and Sedimentology at UFRGS; and currently is a PhD Candidate in Geosciences with focus on Basin Analysis at UFRGS; she also is a Visiting Researcher at Imperial College London during her PhD researching salt tectonics. Her professional experience includes research projects funded by Shell and Petrobras at UFRGS. Roberto A. Scasso, University of Buenos Aires - CONICET Roberto holds a PhD in Geological Sciences from the University of Buenos Aires. He is Professor of Sedimentology and Head Researcher at the University of Buenos Aires – CONICET, focused on Neuquén and Cañadón Asfalto basins. Roberto is a member of AGA (Argentine Geological Association), Argentine Association of Sedimentology, IAS and SEPM. Lucas Cazelli Vasconcelos, Rio de Janeiro State University Lucas is a geologist from Rio de Janeiro State University (UERJ). Currently, he is a Master’s student at UERJ’s post-graduate program with accepted project entitled “Organic Geochemestry and high resolution Chemostratigraphy: Upper Cretaceous of the Southern Santos Basin, Brasil”. He received a research grant for Geology Graduation Student at UERJ’s Stratigraphy and Paleontology Departament (2018/2019). Lucas is a member of SBG (Brazilian Geological Society). Gustavo Andres Camelo Acevedo, Ecopetrol Brasil Gustavo holds a MSc from the Universidade Federal do Rio de Janeiro. With 5 years of experience in the industry, he is Exploration Geologist at Ecopetrol Brasil, in Rio de Janeiro, where he elaborates multi 1D, 2D and 3D basin and petroleum systems models with the aim of evaluate petroleum charge effectiveness through the study of oil generation, migration and accumulation in different basins along the Brazilian continental margin; nowadays he focuses in the Pre-salt of Campos and Santos Basins. He also performs source rock potential evaluation based in geochemical and seismic data; regional analysis and evaluation of exploration opportunities (blocks and prospects) to Ecopetrol Brasil including the analysis of regional tectonics and structural geology. Gustavo is a member of AAPG, ALAGO, EAFE and SPWLA. Adriana Henao, Rio de Janeiro State University Adriana graduated from Rio de Janeiro State University (UERJ). With 10 years of experience in the industry, she is Research and Associate Professor at America University, in Bogota, Colombia, where she teaches Geology, Petroleum Geology and Environment Sediments. Prior to being a Professor, Adriana worked as Exploration Geologist at GranTierra Energy. Adriana is a member of EAGE and SPE.

Author: Márcio Mello, Brazil Petroleum Studies Márcio Mello from Brazil Petroleum Studies, delivers the presentation “Equatorial Margin of Brazil: A Giant Deep-Water Hydrocarbon Frontier of Exploration in the South Atlantic Realm?” at the South Atlantic Basins Virtual Research Symposium, held on 3-4 December 2020. Bio: Marcio Rocha Mello, Brazilpetrostudies (BPS) Marcio holds a PhD from Bristol University, England. With 43 years of experience in the industry, he is the President of Brazilpetrostudies (BPS), Rio de Janeiro, Brazil. Prior to BPS he worked at Petrobras, HRT Petroleum. Marcio is a member of AAPG, ABGP and ALAGO.

Authors: Sean Romito (presenter), Ana Krueger, Paul Mann, University of Houston The Camamu and Almada passive margin off the northeastern coast of Brazil covers an area of 22,000 km2 and is conjugate to the Gabon basin, offshore western Africa. The margin includes: 1) unrifted Precambrian metamorphic continental crust (40 km-thick); 2) proximal and necked thin (20 km-thick) to ultra-thin (5 km-thick) continental crust; 3) distal undetermined transitional crust (4 to 6 km-thick); and 4) Aptian and younger oceanic crust (6 to 8 km-thick). Fission track studies onshore have shown three periods of post-rift (post-Aptian) uplift during the late Cretaceous, Eocene, and Miocene, but little work has been done in the offshore. We investigate the overall tectonic evolution of both the Camamu and Almada basins by structurally restoring two Kirkchhoff PSDM seismic lines recorded to a depth of 40 km.In both the Camamu and the Almada, a 50 km-wide marginal rift developed throughout the Berrasian to Aptian continental breakup between South America and Africa that localized up to 7 km of pre- and syn-rift sedimentation. Crustal extension on both continental and transitional crust occurred through large-offset, basinward-stepping normal faults. Complex, large salt-withdrawal minibasins, up to 2.5 km-thick, formed immediately following evaporitic deposition, pushing the salt basinward into salt pillows and diapirs. A large, Eocene unconformity eroded down to late-rift Aptian sedimentation and matches the largest uplift event quantified onshore. These results are significant in that they quantify the tectonic history of a triple junction with an atypical rift history of both transtension and transpression throughout the rifting process, and are key in understanding the timing of hydrocarbon migration, trapping mechanisms, and basin modeling. Bio: Sean Romito, University of Houston Sean earned a BSc in Geology from the University of Texas at Dallas, and currently is a PhD candidate and research assistant at the University of Houston, where he develops large-scale tectonic research within the Caribbean plate and the Brazilian passive margin. He has experience as intern on prospect generation within onshore US basins; field work as a wellsite geologist in the Permian; and intern on geologic risk within the Texas panhandle. Sean is a member of AAPG and HGS.

Authors: Hualing Zhang (presenter), Paul Mann, Dale E. Bird, University of Houston The Sergipe-Alagoas Basin is a Cretaceous rifted-passive margin basin located along the northeastern Brazilian margin of the South Atlantic Ocean that is a conjugate of the Gabon basin of west Africa. The structural framework is controlled by normal fault systems striking NE-SW and subsidiary transfer faults trending E-W and NW-SE. We investigate the crustal architecture and the nature of the continental-oceanic boundary (COB) of the Sergipe basin by building two regional gravity models (AA’ and BB’) that are aligned with two ION seismic lines recorded to a sub-crustal depth of 30 km. Wells logs and refraction stations were added to better constrain the gravity models. Onshore gravity and magnetic data were integrated with seismic control in order to extend the models eastward across the Reconcavo–Tucano–Jatoba failed rift system. Gravity model A-A’ is oriented NW-SE through the central Sergipe Basin and crosses the Aptian Bahia Seamounts to the southeast, which exhibits a 22-km-deep root into the upper mantle. The rifted continental crust is thicker compared to that seen on gravity model B-B’ with its large seamount influence. Model B-B’, oriented NW-SE through the southern edge of the Sergipe Basin, shows a 3-25-km thick, ultrathin continental crust with a distinct COB. Modeling results suggest that the crust thins abruptly over a distance of 3.5 km from the shelf to the deepwater region. Both gravity models show seaward-dipping reflectors that fill the area separating the continental-edge, marginal rift, and the oceanic crust. These new observations provide important constraints on the crustal and upper mantle framework of the Sergipe Basin that relates to hydrocarbon accumulation, the amount of crustal thickening influenced by Cretaceous-Eocene volcanism, and a tectonic reconstruction of its conjugate margin in Gabon. Bio: Hualing Zhang, University of Houston Hualing is a PhD student at the University of Houston. She is a member of AAPG and AGU.

Authors: Tom Wilson (presenter), Joseph Whiting, Corneliu Cosovanu, Ann Watkins, Anne McAfee, Core Laboratories UK The emergence of a significant submarine fan play, in the ultra-deep waters of the Sergipe Basin, is exemplified by 6 discoveries since 2010. This paper integrates biostratigraphic and sedimentological data to better understand the evolution of the Late Cretaceous deep-water fan systems. Success in the Calumbi play, for example in the Barra, Moita Bonita and Farfan discoveries, is characterised by accumulations within stratigraphic traps basinwards of the Alagoas Hinge Line. Biostratigraphic analysis of exploration wells shows Upper Cretaceous sediment packages, which are thin or absent on the present-day shelf, thicken outboard of the Hinge Line. These packages can be related to the Drift-Transgressive and Regressive sequences and are associated with channel and fan sands. The marked increase in accommodation space occurred during the transition and drift phases, initiated by a basinward shift in the rift / spreading axis. Hyperextension of the continental crust, emplacement of magmatic crust and SDRs gave way to thermal sag and an increase in accommodation space in the outboard region. Extensive core logging of Upper Cretaceous Calumbi sections allowed the differentiation of interbedded coarse-grained sand and gravel-rich intervals into turbidity current and hyperpycnal surge facies, driven by increased fluvial discharge (figure A.). These sediments were transported across a narrow shelf and preserved within stacked channel systems on the steep and terraced slope. Observed facies include inboard bypass deposits giving way to levee-confined slope systems consisting of amalgamated channel complex sets and associated mass transport deposits, and distal lobes characterised by discrete low-density flows. These rock-based observations are integrated with downhole logs and information on the regional geology to extrapolate the sedimentary succession and create palaeogeographic maps. Bio: Tom Wilson, Core Laboratories Tom is a geologist from Kingston University and holds a MSc in Palynology from Sheffield University. With 24 years of experience in the industry, he is Senior Geological Advisor at Core Laboratories, UK, where, as part of the regional studies group his main technical role is reviewing stratigraphic data, coordinating new analyses and interpreting the results to produce consistent stratigraphic interpretations and well correlations; working with regional and reservoir geologists to place the well data in tectono-stratigraphic context, better understanding basin evolution, reservoir distribution and reservoir quality. He spent 16 years at Robertson, initially as a palynologist working principally on West African basins. Subsequently moved to multi-client studies as a Petroleum Geologist looking at basins in the South Atlantic and then around the globe. A move to the proprietary studies department resulted in a change to working on license rounds and prospect analysis, later becoming a Technical Advisor in this department. Upon leaving Robertson he went to Xodus as a Senior Geologist looking at exploration opportunities in Africa and then spent 3 years in the Central North Sea exploration team at Eon E&P, before joining Core Lab early 2017. Tom is a member of AAPG, PESGP and Micropalaeontological Society,

Authors: Randall Etherington (presenter); Eric Newman, TGS The Potiguar Basin is the largest oil-producing region in equatorial Brazil along the onshore and near offshore areas of the basin. The petroleum system of the basin contains lacustrine to marine prolific source rocks of rift to post-rift spanning in age from Barremian through Turonian. Proven reservoir rocks range in age from Barremian to Eocene times. Seal rocks are observed throughout the entire stratigraphic column and are represented by intra-formational lacustrine shales, fine-grained argillaceous sandstones and shales, and thick deep marine pelitic rocks. The Pitu well, announced in December of 2013 became the first deep water oil discovery of the Potiguar Basin. The Pitu well found a 188 meter hydrocarbon column in Upper Aptian sands of the Pescada Formation in a rift structure at depths of 4,300 meters, thus confirming that the proven petroleum system extends into the deep water. Two main play types have been identified. The confirmed ‘Rift’ play which follows the Potiguar oil basin off the shelf is the same play as Pitu and extends across all of the basin. The well-defined horst blocks at Pescada Formation level show several thickened intervals. The greatly anticipated ‘Drift’ Late Cretaceous-Tertiary play is a turbidite sand play of channel sands and toe of slope fans, many with amplitude anomalies. Broadband, long offset 2D seismic clearly shows the Aptian ‘Rift’ play and evidence of the ‘Drift’ Late Cretaceous-Tertiary turbidite channel complex and basin floor fans. The most recent 3D data takes the seismic image and detail of the Cretaceous turbidite channel/fan complexes and Aptian ‘Rift’ structures to an all-new level. Bio: Randall Etherington, TGS-NOPEC Geophysical Company Randall earned a bachelor’s degree in Engineering from Utah State University, and a MSc in Geology from Brigham Young University. His more than 40 years of experience in the industry include several positions in companies as ExxonMobil, Chevron, Shell, Phillips, Devon, YPF-Regsol, Pennzoil, Cobalt, Murphy; Maersk, among others. Currently, he is Exploration Advisor at TGS-NOPEC Geophysical Company, where is responsible for geophysical interpretation and basin analysis. Randall is a member of AAPG and SEG.

Authors: Pedro Victor Zalan (presenter), ZAG Consulting in Petroleum Exploration; Eric Newman, Mike Saunders, TGS With the fantastic exploratory success obtained by ExxonMobil and Apache in Guyana and Suriname it is logical to follow the trend southeastwards, passing through the Zaedyus discovery in French Guyana, into the Foz do Amazonas and Pará-Maranhão Basins in Brazil (Figure 1). The northern portion of the FOZ, bordering French Guyana, had several blocks adjudicated to majors that had acquired 3D seismic and defined several drilling locations aiming stratigraphic traps similar to the discoveries further north. New long-offset, broadband reprocessed, 2D seismic data acquired in deep/ultra-deep waters in the southern part of the FOZ and in PAMA, have unraveled the exciting geology and the enormous petroleum potential of these basins. Three distinct seismic-stratigraphic sequences were mapped in the Drift Sequence: (1) a basal unit composed of Late Albian-Coniacian source rocks, plus abundant turbidite bodies, followed by (2) an intermediate unit displaying low-energy seismic facies, typical of effective seal strata, plus Santonian-Lower Paleogene turbidite bodies, capped by (3) Upper Paleogene-Neogene shales/claystones and enormous amounts of turbidite bodies (Figure 2). The source rock strata had been downwarped by the load exerted by the Amazon Cone and by huge volcanic edifices to depths spanning the entire thermal maturation range (Figure 2). One regional and one local HC kitchens were mapped. HCs emanating from these kitchens tend to migrate towards the compensation highs created in response to these downwarps in the Pará-Maranhão Basin (Figure 2). On these migration routes innumerous stratigraphic and mixed traps were identified, some with very large dimensions, some with strong DHI response (Figures 3-6). The scenario is ready for the replication of the exploratory success happening in Guyana and Suriname and, across the Ocean, in Ghana and Ivory Coast. Bio: Pedro Victor Zalán, ZAG Consulting in Petroleum Exploration Pedro holds a MSc and a PhD from the Colorado School of Mines. With 42 years of experience in the industry, he is independent consultant in petroleum exploration at ZAG Consulting in Petroleum Exploration, in Rio de Janeiro. He worked for 34 years in Petrobras. Pedro is a member of AAPG and ABGP.

Conveners: Lizbeth Calizaya, Ecopetrol Brasil; Renato Darros de Matos, Independent Researcher and Consultant Participants: Márcio Mello, Brazil Petroleum Studies; Sean Romito, University of Houston; Hualing Zhang, University of Houston; Tom Wilson, Core Laboratories UK; Randall Etherington, TGS; Pedro Victor Zalan, ZAG Consulting in Petroleum Exploration Conveners Lizbeth Calizaya and Renato Darros de Matos moderate a discussion with presenters, who answer questions and share final thoughts to conclude Session IV, Northeast Brazilian Basins, at the South Atlantic Basins Virtual Research Symposium. Bios: Convener: Lizbeth Calizaya, Ecopetrol Brasil Convener: Renato Darros de Matos, Guarini Services Renato is geologist graduated from the Universidade de Brasília, Brazil (1979) and holds a PhD from Cornell University (1992). He has 40 years of professional experience, which includes 21 years at Petrobras, 4 years at academia (UFRN) as researcher, founder of Flamoil Services, E&P Director of Potioleo, Aurizonia and Imetame Energia (small independent oil companies); Coordinator and first President of ABPIP (Brazilian Independent Petroleum Producers Association); Exploration Manager of Petrobras International in Libya and Turkey; Management Director of the first board of the government controlled PPSA (Pré-Sal Petróleo S.A.). Currently, he is Director and Senior E&P Consultant at Guarini Services, Natal and Rio de Janeiro, Brazil. Renato is a member of AAPG, ABGP and SBGf. Marcio Rocha Mello, Brazilpetrostudies (BPS) Marcio holds a PhD from Bristol University, England. With 43 years of experience in the industry, he is the President of Brazilpetrostudies (BPS), Rio de Janeiro, Brazil. Prior to BPS he worked at Petrobras, HRT Petroleum. Marcio is a member of AAPG, ABGP and ALAGO. Sean Romito, University of Houston Sean earned a BSc in Geology from the University of Texas at Dallas, and currently is a PhD candidate and research assistant at the University of Houston, where he develops large-scale tectonic research within the Caribbean plate and the Brazilian passive margin. He has experience as intern on prospect generation within onshore US basins; field work as a wellsite geologist in the Permian; and intern on geologic risk within the Texas panhandle. Sean is a member of AAPG and HGS. Hualing Zhang, University of Houston Hualing is a PhD student at the University of Houston. She is a member of AAPG and AGU. Tom Wilson, Core Laboratories Tom is a geologist from Kingston University and holds a MSc in Palynology from Sheffield University. With 24 years of experience in the industry, he is Senior Geological Advisor at Core Laboratories, UK, where, as part of the regional studies group his main technical role is reviewing stratigraphic data, coordinating new analyses and interpreting the results to produce consistent stratigraphic interpretations and well correlations; working with regional and reservoir geologists to place the well data in tectono-stratigraphic context, better understanding basin evolution, reservoir distribution and reservoir quality. He spent 16 years at Robertson, initially as a palynologist working principally on West African basins. Subsequently moved to multi-client studies as a Petroleum Geologist looking at basins in the South Atlantic and then around the globe. A move to the proprietary studies department resulted in a change to working on license rounds and prospect analysis, later becoming a Technical Advisor in this department. Upon leaving Robertson he went to Xodus as a Senior Geologist looking at exploration opportunities in Africa and then spent 3 years in the Central North Sea exploration team at Eon E&P, before joining Core Lab early 2017. Tom is a member of AAPG, PESGP and Micropalaeontological Society, Randall Etherington, TGS-NOPEC Geophysical Company Randall earned a bachelor’s degree in Engineering from Utah State University, and a MSc in Geology from Brigham Young University. His more than 40 years of experience in the industry include several positions in companies as ExxonMobil, Chevron, Shell, Phillips, Devon, YPF-Regsol, Pennzoil, Cobalt, Murphy; Maersk, among others. Currently, he is Exploration Advisor at TGS-NOPEC Geophysical Company, where is responsible for geophysical interpretation and basin analysis. Randall is a member of AAPG and SEG. Pedro Victor Zalán, ZAG Consulting in Petroleum Exploration Pedro holds a MSc and a PhD from the Colorado School of Mines. With 42 years of experience in the industry, he is independent consultant in petroleum exploration at ZAG Consulting in Petroleum Exploration, in Rio de Janeiro. He worked for 34 years in Petrobras. Pedro is a member of AAPG and ABGP.