Fault
Propagation Folds and Relay
Zones and Their Influence on the Distribution of Syn-Rift Sandbodies: Examples
from the West Flank of the Oseberg Field, Norwegian North Sea and the Hammam
Faraun
Fault
Block, Sinai, Egypt
By
Stephen Martin Corfield1, Tom Dreyer2, Rob Gawthorpe1
(1) University of Manchester, Manchester, United Kingdom (2) Norsk Hydro Research Centre, Bergen, Norway
Fault
propagation folds and relay zones and their influence on the
distribution of syn-rift sandbodies. Examples from the west flank of the Oseberg
Field, Norwegian North Sea and the Hammam Faraun
fault
block, Sinai, Egypt.
Stephen Corfield1, Tom Dreyer2 and Rob Gawthorpe1 1 University of Manchester UK, 2 Norsk Hydro Research Centre, Norway.
Recent research in the subsurface of the Norwegian sector of the North Sea
has revealed that relay zones and related hangingwall deformation in the form of
fault
propagation folds have had a major impact on the distribution of synrift
sandbodies. These results complement over ten years of fieldwork by the
University of Manchester in Sinai. In both areas, the growth and linkage of
extensional faults bounding tilted
fault
blocks during the evolution of the rift
basin has resulted in a focussed sand supply to the hangingwall depocentres. The
main sediment supply route has been via relay zones. Lateral and vertical growth
of faults has also resulted in the development of
fault
propagation folds and
emergent
fault
block crests.Sands are considered unlikely to be laterally
extensive in such a complex setting and the outcrop examples indicate rapid
lateral thickness variations in relation to the hangingwall folds. These
conclusions are supported by 3D seismic data on the west flank of the Oseberg
field in the Norwegian North Sea where Upper Jurassic syn-rfit sand bodies occur
in canyons eroded through relay zones. Extensive use of 3D visualisation
techniques (formation sculpting, voxel rendering, virtual reality) coupled with
seismic modelling has been used to map the geometry and distribution of the syn-rift
sandbodies.
The combination of these technologies coupled with the integration of
structural and stratigraphic examples from outcrop has lead to an increased
understanding of the interaction between fault
growth and linkage with the
eventual aim of delineating subtle syn-rift plays.