Abstract:

Taking advantage of the extensive seismic data, the structure palaeogeomorphology characteristics and sand bodies distribution regularities of Paleogene Wenchang Formation in Enping Sag are discussed by correlated theories on the characteristics of palaeogeomorphology, identification of ancient valley and joint phase tracking. The causes and plane distribution of the sand bodies of Wenchang Formation are closely associated with the deposition of ancient geographical background and the ancient valley. The northern steep slope of Enping Sag is controlled with the fault and the ancient valley. It develops a series of north offlap fan-delta glutenite bodies which interactively touches with the mid-deep lake facies mudstones, and its development period and scale is closely related to the boundary fault activity. The EP18-1 inherited palaeohigh has controlled the ancient valley development and ancient landform pattern of the southern slope, and the southern slope zone is divided into two ancient valley source supply systems. They control the distribution direction of the braided river delta in the south slope of EP17 and EP18, while the EP18-1 inherited palaeohigh develops largescale beach bar sand body.

Key words: Enping Sag, Wenchang Formation, palaeogeomorphology, ancient valley, glutenite bodies, braided river delta, beach bar