Lacustrine Sequence Stratigraphy and Computer Modeling of the Erlian Fault Basin, North China: ABSTRACT

Erlian fault basin, a major oil prospecting and producing area in North China, comprises about 40 grabens and half grabens. The basin was formed by extension from Jurassic to Early Cretaceous and filled with more than 3000m thick of clastic lacustrine deposits. Based on the integrated analysis of seismic profiles, logging and cores, 5 sequence sets and 12 sequences, bounded by discontinuous, have been identified. Three types of lacustrine sequences have been identified: (1) deep lacustrine basin sequences, mainly consisting of sublacustrine fan and fan delta systems; (2) shallow lacustrine basin sequences, predominately composed of fan delta and braided delta systems and (3) shallow lacustrine and fluvial basin sequences. The sequence architecture and the basin filling evolution were controlled by the basin structural framework and lacustrine level changes. The computer modeling study by using the backstripping and forward modeling technique has shown that the major unconformities confining the sequences may be generated by the variation in tectonic subsidence rate caused by episodic lithospheric stretching. The model have also be used to predict the sequence architecture and the facies distribution in the basin.