Establishment of Isochronous Stratigraphic Framework and Reservoir Prediction of Fluvial Strata

Hongwen Deng, Hongliang Wang, and Li Gu
School of Energy Resource, China University of Geosciences, Beijing, China

Fluvial facies strata are one of important reservoirs in Meso-Cenozoic continental basins in China. Conventional sequence stratigraphy interpretation techniques based on seismic stratigraphy in passive continental margin is generally considered difficult to be applied to fluvial facies

Taking Yabus-Samma Member, Lower Tertiary, Palogue Oilfield in Melut Basin, Sudan as an example, the paper discusses how to establish isochronous high-resolution stratigraphic framework of fluvial strata based on cores, well logs and 3-D seismic data by using base-level cycle recognition methods. It is essential to recognize the genetic types of fluvial system and the types of facies tracts, and also the autocyclicity caused by fluvial avulsion and the allocyclicity caused by base level change. Study on the sedimentologic and strtigraphic responses of different facies to base-level change, especial to the turnround position of base-level. Chronostratigraphic framework of studied fluvial sediments has been established by correlating the base level fall to base level rise or rise to fall turnround points.

The studying interval is dominated by braided delta plain in the early stage and fluvial plain in dry climate in the later stage, consisting of braided channel facies, interchannel facies, overbank facies and flood plain facies. As reservoirs of Palogue oilfield, channel sandstones distribution have been predicted in high-resolution isochronous framework by using integrated multiple-information combining geologic interpretation, well controlled seismic inversion and extraction of seismic attribution.

AAPG Search and Discovery Article #90078©2008 AAPG Annual Convention, San Antonio, Texas