Stratigraphic Prediction in Tectonically Active Basins

By

Stephen S. Flint¹, John A. Howell², David Hodgetts¹, Matthew Brettle³

(1) University of Liverpool, Liverpool, United Kingdom (2) Strat Group, University of Liverpool, Liverpool, United Kingdom (3) Stratigraphy Group, University of Liverpool, Liverpool, United Kingdom

 Sequence stratigraphy can be applied successfully to tectonically active basins in terms of the 4-D evolution of accommodation and sediment supply. In extensional basins and growth-faulted margins, fault linkage and growth history are critical parameters in understanding spatial accommodation distribution and, when convolved with transfer zone/relay sediment entry points allow prediction of facies. In foreland basins, the interaction of basement discontinuities with the flexural load result in differential accommodation generation, which affects shoreline orientations and character of lowstand deposits. In both extensional and foreland basins, salt withdrawal results in aggradational stacking patterns and suppressed sequence boundaries. Structural topography may amplify tidal conditions at multiple regional sea level positions, without the presence of incised valleys. In complex strike-slip settings local areas can evolve from excess accommodation, through filled accommodation to negative accommodation as blocks subside, rotate, lock and invert. Although stratal geometries vary in tectonically active basins, the fundamental cornerstones of accommodation and sediment supply remain the key parameters in understanding and predicting facies and therefore reservoir/seal distribution. Examples will be used from the North Sea, the U.S. Western Interior Basin and the Russian Far East.