HGS International Explorationists Group Dinner Meeting
Monday January 19, 2004
Westchase Hilton Hotel
9999 Westheimer
Social Hour 5:30, Dinner 6:30, Talk 7:30
"Brazilian Deepwater Fold Belts:Tectonic Drivers and Structural Styles of Potential Traps"
Scott E Thornton, Shell International E&P, Inc., Peter Mullin, Amerada Hess, and David D. J. Stewart, Shell International E&P, Inc.
ABSTRACT:
Deepwater fold belts in the emerging and frontier basins in Brazil are structurally quite different than the more explored Santos, Campos and Espirito Santo Basins (the Southern Salt Basin). One key difference is the nature of the mobile substrate. In the deep water fold belts of the Equatorial Margin and extreme northeast Brazil, little salt exists in the deep water continental margin, although shallow water salt is penetrated in the Potiguar and Sergipe-Alagoas basins. As a result, mobile shales, sometimes overpressured, provide the base of the decollement(s). Continental margin structural imprints from breakup of the North Atlantic and South Atlantic provided strong contrasts in structural fabric of the continental margin as well, separating these underexplored fold belts into 2 generic sectors: 1) southern sector from Cumuruxitiba to Parnaiba-Pernambuco basins where roughly east-west rifting occurred and 2) northern sector along the Equatorial Margin from the Ceara to the Foz do Amazonas basin, where North Atlantic oblique rifting initiated Berriasian rifts and later drifting. Some limited parts of the Equatorial Margin also have Triassic rifts, akin to eastern North America. Fold belts and their contiguous listric-faulted nearshore structural zones will be dissected from the south to the north, from the Cumuruxitiba to the Foz do Amazonas basins.
The major tectonic drivers and structural controls for formation of these fold belts will be discussed relative to the general stratigraphic section known in shallow and deep water. In addition to the Campanian uplift, Middle Eocene and Late Middle Miocene Andean orogenies have triggered fold belt formation. The lack of significant exploration in these deepwater fold belts points to upside potential in high-risk and potentially high-reward structural segments.
BIOGRAPHIES:
Scott E Thornton (speaker) has worked for Shell, Unocal and independents, generating exploration evaluations and regional studies of the South Atlantic continental margins. He has worked on Brazil since 1992, including 4 bid rounds. In addition, he has conducted block/prospect evaluations, regional studies and well operations in offshore North Alaska, offshore Southern California, South Asia, SE Asia, China, Australia and the Subandean Zone in South America. He currently works as a contract consultant in Shell International E&P, Inc. working on Brazil exploration. Scott's prior fold belt experience has been in onshore Pakistan, onshore and offshore western Burma, Ecuador, Peru, and offshore north Alaska.
Peter Mullin is currently Exploration Director for Amerada Hess’s Brazil group, a part of Hess’s South Atlantic Margin Team. Prior to joining Hess this year, Peter worked for some 24 years with Shell, primarily on exploration new ventures in South America and West Africa. He was Shell’s exploration manager first for Angola and then Brazil (working all the Brazil bid rounds), and most recently was Shell’s Head of Evaluation for Trinidad. In addition to South Atlantic margin basins, he has worked the Subandean fold belts in Bolivia, Peru, Columbia, Venezuela and Trinidad, and the Barbados accretionary prism in the Caribbean.
Dave Stewart is Team Leader, Brazil Team, Subsurface Evaluation, Shell International E&P, Inc. in Houston. Dave has worked on Brazil since Bid Round 0 and, in addition to coordinating Bid Round Evaluation, has performed both regional and prospect analysis throughout the Brazilian marginal basins. Dave came to Shell from Robertson Research to join The Group’s seismic stratigraphy effort in the Research Centre in Rijswijk, Holland. Dave has also had assignments at Shell on the Norwegian and British North Sea, and the Gulf of Mexico.
POSTER SESSIONS:
“Global Analogs and Prediction of Lacustrine Source Rocks: SE Asian and <?xml:namespace prefix = st1 ns = "urn:schemas-microsoft-com:office:smarttags" />Brazilian Basins”
By Scott E. Thornton and David D. J. Stewart, Shell International E&P, Inc.; Gilbert R. Stern, IGC; Joe Curial, Unocal Corporation; George E. Moore, Consultant; Robert K Merrill, Samson Resources Company; Rex Cole, Mesa State College; Gregg Blake, Unocal Corporation.
<?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" />
“Syn-rift and Transpressional Plays along the Equatorial Margin: Brazil and Africa.”
By Ian Davison, EARTHMOVES