Sequence stratigraphic responses to shoreline-perpendicular growth faulting in shallow marine reservoirs of the Champion field, offshore Brunei Darussalam, South China Sea



Hodgetts, D.1, Imber, J., Childs, C., Flint, S.1, Howell, J.1, Nell, P.A.R.2 & Walsh, J.J.
1 - Strat. Group, Department of Earth Sciences, University of Liverpool, Brownlow Street, Liverpool L69 3BX, UK
2 - Badley Earth Sciences Ltd, North Beck Lane, Hundleby, Spilsby, Lincolnshire PE23 5NB, UK

Abstract - The Champion field, offshore Brunei Darussalam, comprises a thick Middle-Upper Miocene succession of shallow marine sediments associated with major growth fault systems and deposited as part of the paleo-Baram delta. The structural evolution of the Champion field has resulted in an unusual situation where growth faults strike perpendicular to the paleo-shoreline orientation. Shoreface parasequences and tidal-estuarine complexes are mapped directly from 3-D seismic data calibrated from wells. The seismic interpretations provide chronostratigraphic correlations that are more robust than some well-based markers as the seismic interpretations have better spatial coverage. Depositional responses to growth faulting are defined by two end-member models (a) layer thickening and (b) addition of layers in the hanging wall, with layer addition making correlation across faults problematical. Growth may be accommodated by either or a combination of these processes, with areas of layer addition being related to transgressive events in the hanging wall. Topographic changes thought to be associated with fault movements may fundamentally change shoreline type, sand body orientations and petrophysical properties for discrete periods of time. These stratigraphic complexities are linked spatio-temporally to accommodation history but cannot be adequately predicted from well data alone.


Bulletin of the American Association of Petroleum Geologists 85, 433-457, 2001.