Abstract:

Yi-Shu graben had undergone two major development processes of early faulted-depression and late died-out.These processes could correspond to the stage of major tectonic evolution,forming 4 overlapping sequences and 20 sequences.A comprehensive analysis of the distribution of source rocks and the characteristics of palaeocurrent etc.indicates that there are 3 resource areas in the upright fault depression.From Xinancun Formation to Dalianhe Formation,sediments from the deep lake facies might have migrated gradually to the sediment center,causing gradually change of layer position of hydrocarbon rocks which existed in the stage of strong faulted-depression and early stage of faulted-depression.Oil and gas accumulations in Yi-Shu graben are mainly distributed in lowstand system tracts while only small amount of the accumulations distributed in highstand system tracts.

Key words: sequence stratigraphy, deposition model, hydrocarbon rock, oil and gas accumulation, Yi-Shu Graben