Abstract:

Daqing Placanticline is the most important oil-gas structure in the Songliao basin, and the Fuyu oil layer is one of the main oil-bearing formations. On the basis of well drilling, well logging and high reflection seismic data and so on, Fuyu oil layer can be divided into two third-order sequences and seven fourthorder sequences. Its reservoir sand body is anastomosing river channel and meandering river channel deposit under fluvial-river environment, sand body thickness varies fast horizontally. The channel sand body is hard to predict and identify. As for sedimentary evolution, the evolutionary process of the river channel is meandering channel-anastomosing channel-distributary channel; Crevasse-splays expand from F2.2 to F1.3, and contract even to vanish along with the transgressive development; The color of floodplains changes gradually from red to sage green and gray and the distribution area contracts during the base level ascending and lakes developing. Lacustrine develops from the early isolated lake among rivers to the later stable lake all over the whole study area. Sequence architecture and sedimentary response are controlled by the tectonic background of thermal subsidence in the Songliao basin, in addition, influenced by climate and provenance.

Key words: Daqing Placanticline, Fuyu oil layer, sequence architecture, filling response, petroleum gas