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Characterization and architecture of fluvial sand bodies in a intracratonic alluvial fan

Conference · · AAPG Bulletin (American Association of Petroleum Geologists); (United States)
OSTI ID:6850199
;  [1]
  1. Delft Univ. of Technology, Delft (Netherlands)
The fluvial deposits of the Tortola alluvial fan of late Oligocene to early Miocene were deposited in the intracratonic Loranca Basin (Spain). the fluvial facies comprise individual and amalgamated sand bodies embedded in flood-plain fines. The succession is a labyrinth-type reservoir analog. A distal and proximal fan locality have been compared. The sand bodies were characterized and quantified by means of three-dimensional (3-D) morphology and facies analysis, sandbody size statistics, permeability and gamma-ray log profiles, and geometry of permeability baffles. A classification of the sand bodies in six genetic types was established: meander-loop, low-sinuosity channel-fill, braided channel-fill, deltaic, interchannel bar, and crevasse-splay deposits. This classification is conditioned by a set og geological rules. The external geometry, internal organization, and spatial arrangement of the genetic types is determined by variation in hydrodynamic conditions, sediment supply, fan morphology, and basin subsidence. Significant differences in reservoir quality exist between the genetic types, and between the two fan localities. Analysis of the sequential development of the two localities shows that the 3-D architecture is the result of coalescing fan depositional systems: a minor fluvial fan systems from the eastern basin margin, and local minor fluvial systems. Shifting of the channels on the fan surface due to avulsion processes, differential basin subsidence, and tectonic movements influenced fan formation and hence reservoir quality.
OSTI ID:
6850199
Report Number(s):
CONF-9310237--
Conference Information:
Journal Name: AAPG Bulletin (American Association of Petroleum Geologists); (United States) Journal Volume: 77:9
Country of Publication:
United States
Language:
English