Renqiu buried hill oilfield is one of the big oil fields with high productivity in China even in the world.The buried hill trap is 30 km

2

in north-south

7 km

2

in east west with an area of 183 km

2

.The reservoirs are carbonate rocks of Lower Palaeozoic

Middle and Upper Proterozoic

the source rocks are pelite of Es

3+2

the caprocks are mudstone and halite of Es 1+Ed.The major oil pools

resulted from NWW striking Tongkou transformation belt and NNE striking Renqiu uplift

are in Middle Proterozoic carbonate rocks in the northern part of the buried-hill.In Es

3+2

depositional period

the transformation belt displaced northward to Mo-14 ～Mo-2 Wells neighborhood.Then Renqiu uplift subsided under the water and became the buried hill.Lingcheng subsag in Baxian sag and Renxi subsag in Raoyang sag which are situated in two sides of the buried-hill provided rich hydrocarbon source and mingling crude oil for Renqiu Oilfield.In Es

1

～Ed period

the transformation belt moved north to Gaojiapu area

resulted in the recession of the two subsags

and formed regional mudstone caprock.In Ed～N period

source rocks matured and formed Renqiu oilfield of buried-hill trap type.