By comprehensive use of drilling data, analysis assay, core data, etc., the sedimentary characteristics of sublacustrine fan in the second member of Liushagang formation in the western area of Fushan Sag, Beibuwan Basin are studied. Through drilling calibration and with the seismic attributes analysis, the spatial distribution of sublacustrine fan is described in detail. The research shows that the sublacustrine fan formed along the side of slope belt, and was controlled by the faulted slope break background formed by synsedimentary faults. The slumps of the northern braided delta front were transported via multi-fault-terrace to the lake bottom and the sublacustrine fan was formed. The fan was with the characteristics proximal to source area, and of multi-superimposed development. They were formed during the late of the lowstand period, including the turbidite and slump types. The trigger mechanism of the fan is the intensive volcanic activities within the sag. There are thick dark mudstones in the upper and the lower parts of the fan, which constitute the main source rocks in the sag and are significant for petroleum exploration.

sublacustrine fan  /  sedimentary characteristic  /  seismic attributes  /  Fushan Sag