Sandbodies-Conduit Architecture and Oil Migration of JX1-1 Oilfield in Liaodong Bay Sub-Basin, Bohai Bay Basin

Abstract

An integration of geophysics and geochemistry analysis was employed to investigate the sandy carrier-bed architecture and oil migration and accumulation of JX1-1 oilfield. The results show that fan delta and braid delta sandstones are dominant carrier-bed for oil migration and accumulation in the study area. In the 3D seismic profiles, the fan delta is characterized by a downlap seismic reflection, and the braid delta is characterized by an obvious progradation seismic reflection. In the Liaodong Bay sub-basin, the E3d3 source rocks are characterized by relatively low gammacerane/aßC30hopane and low 4-methyl steranes/?C29 steranes; the E2s1 source rocks are characterized by relatively high gammacerane/aßC30hopane and low 4-methyl steranes/?C29 steranes; and the E2s3 source rocks are characterized by relatively low gammacerane/aßC30hopane and high 4-methyl steranes/?C29 steranes. Depending on these oil-source parameters, we concluded that the hydrocarbon in JX1-1 oilfield was mainly originated from E2s3 and E2s1 source rocks. The stratigraphic contacts between the source rocks and the delta depositional systems are very beneficial to the oil migration of JX1-1 oilfield. Therefore, two migration pathways had been established: the migration pathway 1 is the major conduit for the crude oil from E2s3 source rocks, and the migration pathway 2 is the major conduit for the crude oil from E2s1 source rocks. Finally, the pathway 1 merged into the pathway 2 in three-dimensional space.

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