AAPG ANNUAL CONFERENCE AND EXHIBITION
Making the Next Giant Leap in Geosciences
April 10-13, 2011, Houston, Texas, USA
Tectonic Controls on an Unconventional Sediment Transport Pathway Interpretation Used 3-D Seismic Data Analysis in Non-Marine Rift-Basin Setting: An Example from the Paleogene of Western Slope of Bozhong Sag, Bohai Bay, East China
Bohai Bay basin is a classic non-marine rift-basin and an important hydrocarbon-bearing basin in East China. Due to lack of enough well data, the diversity of sediment transport pathway and their controlling deposits was analyzed using the recent 3-D seismic data in the western slope of Bozhong sag, Bohai Bay basin. The result showed that three types of sediment transport pathway were discovered in Paleogene of the western slope of Bozhong sag, including sediment transport pathway of paleo-channel, fault trough and structural transfer zones. The deposits of study area were controlled mainly by fault trough sediment transport pathway derived from Shaleitian uplift. Five terms of fault through were identified in the study area and their distribution directions are paralleled to fault zones strike in NEE direction. Compared to sediment transport pathway of paleo-channel, structural transfer zones, and longitudinal gravity currents sediment, fault trough was an unconventional sediment transport pathway in non-marine rift-basin setting. The types of fault through could be subdivided single fault trough with wedge shape external geometry form of seismic reflection and double fault trough with sheet shape external geometry form of seismic reflection. The seismic sections along the fault through strike showed the typical progradational seismic reflection. On the basis of the an integrated analysis of seismic multi-attributes, 3-D seismic geomorphology, sedimentary facies and sedimentary facies model, the deposits controlled by fault trough sediment transport pathway were the belted distribution in NEE direction, lying between parallel faults or fault zones, and their sedimentary facies boundary was recognized quantitatively.
The fault trough sediment transport pathway found in the Paleogene strata of western slope of Bozhong sag was believed to be strongly controlled by the tectonic evolution of the rift basin and may have important implications to basins with similar tectonic setting elsewhere.