Abstract:

According to the data of cores, logging and some seismic data, under the guidance of the theory of highresolution sequence stratigraphy, the Paleogene is divided into two super long-term sequence cycles, 6 long-term sequence cycles, 18 middle-term sequence cycles and some dozens of short-term sequence cycles. Based on interfaces and structure characteristics, by selecting the rising and falling base-level phases of each long-term sequence cycle as the isochronous mapping unit, the sequence-based lithofacies and paleogeography maps are drawn. The evolution rule is deduced: during the phase of LSC2 and LSC3, the primary depositional environments are shallow lake and sublacustrine turbidite fan; sublacustrine turbidite fan and delta are developed during the phase of LSC4; and during the phase of LSC5 and LSC6, delta and shallowlake become prevalent. Frombottomto top, shallowlake, sublacustrine turbidite fan and delta depositional configuration formed, and the sand body extended, which can provide basis for forecasting reservoir sand body.

Key words: paleo fall, activity rate, growth index, fault activity, Qianquan area