Application of Sequence Stratigraphy to Exploration and Development in Eastern Pearl River Mouth Basin, South China Sea
Shaokun Yang, Huang Lifen, and Xu Shice
Some appropriate conditions for applying sequence stratigraphy in PRMB exist: 1. the PRMB is a Cenozoic extension basin with weak tectogenesis after rifting; 2. the late Tertiary successive sediments deposited over the area from coast to deep marine basin are well developed and their seismic reflection is good in quality; and 3. high resolution quantitative biostratigraphy has provided more precise data of eustasy.
Twenty-two third order sequences since 30Ma were identified and are
correlative to global cycle chart, but TB2.1 can be further divided into two
third-order sequences. The 22 sequences from a "retrograding stacking pattern"
which resulted in no large constructive delta or delta-related rollover
anticlines. However, widely deposited seal rock possibly sealed the
incised-valley, basin floor fan (BFF), and transgressive sandstone to form valid
stratigraphic traps. Stratigraphic traps are particularly important in future
exploration because of poor anticline trap
types
in the basin. Some
stratigraphic traps can be predicted after studying the distribution of
systems
tracts
in each sequence as a basic exploration unit. The BFF of TB2.1 which is
closed to the source kitchen area could form large subtle
trap
.
Using the parasequence as a basic unit in reservoir scale will provide a new
method to discover new reservoirs. For example, new oil reserves within the
predicted stratigraphic trap
related to K22, which can be divided into several
parasequences in C.A. 16/08, were obtained after drilling.
Sequence stratigraphy has become a valid high resolution tool for chronostratigraphic correlation and fine-division and exploration of stratigraphic traps.
AAPG Search and Discover Article #91019©1996 AAPG Convention and Exhibition 19-22 May 1996, San Diego, California