New Perspective of Hydrocarbon Accumulation Pattern in the Middle South of Lixian Slope, Central Hebei Depression

Abstract

The traditional understanding of hydrocarbon accumulation patterns in the middle south of Lixian Slope was based on the assumption that oil and gas migrated through connected sandbodies in lower first Member of Shahejie Formation (Es1x) and third Member of Shahejie Formation (Es3) to the boundary faults, and then vertically along the faults. It is suggested that no hydrocarbon would be found beyond source rock layers of the middle south of Lixian Slope. But this pattern is contradicted with newly discovered reservoirs. Through comprehensive study of faults activity periods and sedimentary system, the results show that the late period development and late period attenuation faults act as the vertical migration path, while connected sandbodies provide lateral migration path for oil and gas. Based on oil-source correlation and the distribution of discovered reservoirs, the hydrocarbon accumulation pattern in the south of Lixian Slope is characterized by 2 source rocks; faults and connected sandbodies meshwork migration; accumulated in fault nose traps of shallow layers. This pattern reveals that the shallower formation in the middle south of Lixian Slope would be the next exploration area through finding subtle structure traps by seismic interpretation and accurate sedimentary microfacies characterization.

AAPG Datapages/Search and Discovery Article #90189 © 2014 AAPG Annual Convention and Exhibition, Houston, Texas, USA, April 6–9, 2014