Abstract: By means of sequence stratigraphy, seismic sedimentology and modern sedimentology theory, the comprehensive analysis of the logging and well logging data from 128 wells, 25 000 km 2-D seismic profile and a part of 3-D seismic data in Tabei area is conducted, and five 3rd-order sequences (Tsq1-Tsq5) bounded by unconformities are identified in the Triassic. Tsq1 and Tsq2 belong to the Lower Triassic, Tsq3 and Tsq4 belong to the Middle Triassic and Tsq5 belongs to the Upper Triassic. All the five sequences are composed of the low-stand system tract dominated by braided river, meandering river and delta and the transgressive system tract dominated by littoralshallow lake, semi-deep lake and deep lake. The tectonic movement, lake level change and sediment supply are the main controlling factors of the Triassic sequences. According to the analysis of sequence evolution and petroleum geology conditions, the complex channel and delta distributary channel developed in low-stand system tract are favorable explorative targets for lithological trap's reservoirs.

Key words: Tabei, Triassic, sequence stratigraphic character, sedimentary system, low-stand system tract, lithological trap