High-resolution sequence architecture and its control over reservoir architecture in Nm I & NmHI oil groups, Gaoqiannan area

Key words:  stratigraphy  sequence architecture  reservoir architecture  fluvial facies  intercalation

Abstract:

The base-level change and the inter-architectures of meandering river sands，especially the relationship among the base-level change and the development degrees of intercalations and the intercalations occurrence were researched by using the high-resolution sequence stratigraphy and the reservoir architecture element analysis. The conclusions are as follows ； Hie Nm II & NmlH oil groups develop three complete mid-term base-level cycles, two incomplete mid-term base-level cycles, twelve short-term base-level cycles and nineteen ultra-short term base-level cycles. The types of the base-level cycles can be divided into upward-deepening and upward-shallowing asymmetry, incomplete symmetry dominated by uprising, and nearly complete symmetry. When the base-level is low, the channels are wide and cut each other seriously t the point bars are developed ,and the inclinations and the drilling frequencies of later-accretion layers are small. When the base-level is high, the single channel is narrow and deep, so the channel sands bindingly insert into the mudstones, the development degrees of point bars are poor，but the embankments are developed，and the inclinations and the drilling frequencies of later-accretion layer are high.