Abstract: Non-Marine Sequence Stratigraphy of the Enping Sub-Basin, the South China Sea
HUANG, LIFEN, and LIANG WEI, China Offshore Oil Nanhai East Corporation, Guangzhou, China
A sequence stratigraphic framework of the Paleogene fluvial-lacustrine succession in the Enping Sag, the South China Sea can be constructed through the recognition and correlation of regional tectonic unconformities. It consists of four second order sequences respectively named as SI, SII, SIII, and SIV which correspond to Vail's super sequences. Each of the sequences bounded by the unconformities reflects a distinctive stage of the basin evolution and represents a long-term base level transit cycle. Each of the long-term cycles usually has several stacked medium- and short-term transit cycles. All of the unconformities can be correlated and traced regionally. This study suggests that the second-order sequences are the basic units in terms of petroleum systems and basin fill.
The sedimentary facies of the sequences were mapped by seismic
facies analyses and drilling data. The depocenter
moved eastwards
in the sequences from the lower to the upper. Deep lake mudstones
were deposited mainly in the sequences SI and SII. Shallow lake and
swamp mudstones with coal beds were well developed in the sequences
of SII and SIV. They are important source rocks in the Enping Sag.
Sandstone packages of the sequences prograded also eastwards and
become gradually widespread and thicker from the lower to the
upper.
This study indicates that the sequence stratigraphic methodology can be employed in the lacustrine rift basins. The sequence stratigraphic framework can help predicting the habitats of petroleum systems in the basin.
AAPG Search and Discovery Article #90937©1998 AAPG Annual Convention and Exhibition, Salt Lake City, Utah