This paper determined the lower limits of physical properties for the effective coarse-grained clastic reservoir rocks in different intervals of the Shahejie Formation on northern steep slope of Bonan subsag

the Bohai Bay Basin by integrating the distribution function curve and production test methods combined with logging and production testing data.The relational expressions between the lower limits of physical properties and depths were also defined through matching.On this basis

this paper analyzed the effects of lithology

sedimentary facies

diagenetic stage and formation pressure on the formation of effective reservoir rocks.The lower limits of physical properties of effective reservoirs decrease with the increasing depth.Favorable sedimentary facies is the key factor controlling the development of effective coarse-grained clastic reservoirs

and determine reservoir quality.The effective reservoirs area are mainly distributed in the western slump turbidite fans and the midfan of the central and eastern nearshore subaqueous fans in the study

the latter is better.Diagenesis also affect reservoir quality to a certain extent.The coarse-grained clastic reservoirs developed mostly at A

1

and A

2

substage of middle diagenetic stage

which correspond to the major hydrocarbon generation stage during organic thermal evolution

which is favorable for the formation of secondary porosity

with dissolution improving the quality of deep reservoir rocks.

Formation pressure has little effect on effective reservoir rocks.