The Bozhong Sag is not only the depocenter of the Bohai Bay Basin

but also an important oil/gas-bearing sag in the Bohai Bay Basin.The reservoirs surrounding the Bozhong Sag are mostly fault-controlled structural or structural-lithological reservoirs.The patterns and degrees that these faults control on petroleum reservoirs directly determine the evaluation of structural traps and exploration strategy.By detailed structural characterization of 237 petroleum reservoirs with shallow to medium depth in the Bozhong Sag

this paper statistically analyzed multiple parameters

e.g.

faulting classification

faulting mechanism

fault throw

faulting activity

fault strike/dip

combination styles

plain view geometry

screening types

SGR

etc.Our study suggested that

with proper assemblage of primary faults and minor faults

faulting characteristics contributing to petroleum accumulation includes:striking NNE or EW/NE

dip angle of 66°-80°

fault throw of 20-150 m

faulting rate of 10-30 m/Ma

SGR

>

0.3

R

m

>

0.35

multiple assemblage styles (e.g.

oblique crossing

en echelon

Y-shape

semi-flower and stepwise faults) and antithetic screening.In plain view

it is more favorable for hydrocarbon accumulation in positions where faults are intersecting and convex section.In general

fault sealing property is the key factor controlling hydrocarbon accumulation in structural traps.The fault sealing property is determined by faulting rate

scale and fault types.