Fan delta coarse clastic rocks on steep slopes of faulted lacustrine basins have large variability in spatial distribution due to the joint control of various geological factors.Various data including core

log and seismic data are integra-ted to investigate the spatial distribution characteristics and the main controlling factors on formation of the fan delta coarse clastic rocks in the 2

nd

to the Upper 4

th

Member of the Eocene Shahejie Formation on the periphery of Changdi fault zone in Gubei sub-sag.The study results show that the development of fan delta coarse clastic rocks are controlled by the intensity of fault activity

change of lake level and sediment supply.The contributions of each influential factor are different in different areas

resulting in the differences of distribution of these fan delta coarse clastic rocks.In the northern part of Changdi fault zone

fault activities are strong and sediment supply is sufficient

thus the fan delta deposits are large in scale and are characterized by vertical aggradation of multiple stages on sectional view.In addition

large slump turbidite fans are common in fan front.On the contrary

in the southern part of the fault zone

faulting is relatively weak and sediment supply is insufficient

thus the fans are small in scale and show a superimposition pattern of early retrogradation and late progradation.Owing to the alternative activity of secondary faults

the fan delta coarse clastic rocks are characterized by wedge-shaped superimposition of multiple stages in the direction of perpendicular to provenance.In general

the distribution of oil and gas in the study area are controlled by favorable sedimentary facies zones

lateral pinch out of the fans and sealing of top mudstone.