Comparative Anatomy of Continental Margins at the Basin Scale: Variations in Rift Geometry and Continental Margin Architecture in Relation to New Play Identification

Horn, Brian W.¹; Danforth, Al⁴; Dinkelman, Menno G.¹; Emmet, Peter A.⁴; Graham, Rod⁵; Helwig, James⁴; Kusznir, Nick⁶; Nuttall, Peter¹; Pindell, Jim²; Radovich, Barbara¹; Whittaker, Richard^3
1ION Geophysical, Houston, TX.
²Tectonic Analysis, Duncton, United Kingdom.
³Geoarctic International, Calgary, AB, Canada.
⁴Consultant, Houston, TX.
⁵Consultant, Oxford, United Kingdom.
⁶Earth and Ocean Sciences, University of Liverpool, Liverpool, United Kingdom.

In the past 20 years hydrocarbon exploration along continental margins has led to the discovery of giant oil fields and play concepts. Several margins are being reevaluated with new data acquisition and depth-imaging of long offset 2D seismic data. These data are often 400-500 km transects across dip, 1,000-2,000 km along strike and provide a basin-scale perspective that demonstrates a variety of rifting geometries. Previous basin-scale seismic data have not satisfactorily imaged crustal architecture in areas of complex structure, volcanic flows and salt layers; however, these new data image the entire sedimentary and crystalline section down to Moho, creating the framework to compare basins worldwide. Reconstruction of conjugate margins with these data sheds light on the style of breakup, distribution of source / reservoir rocks in poorly known areas, and structural and stratigraphic traps, identifying frontier play concepts and fairways.

Data from areas with little or no well control in the Gulf of Mexico, East Africa, India, South America, West Africa, Northeast Greenland, Beaufort Sea, South Australia and Indonesia highlight examples of various rift styles, volcanic versus non-volcanic margins, tectonic versus thermal subsidence, mechanisms of early transport and structuring of salt, continent-ocean boundaries and exhumed sub-continental mantle. Imaging the entire sedimentary section (with strong inferences for basement composition) demonstrates styles of continental stretching and thinning, deduction of crustal thickness, and definition of structures and crustal types at the continental-oceanic boundary. Interpretations integrating deep structure and depositional systems provide data constrained prediction of heat flow for maturation modeling and identify frontier plays with viable source rocks and reservoirs.

AAPG Search and Discovery Article #90155©2012 AAPG International Conference & Exhibition, Singapore, 16-19 September 2012