SEDIMENTARY CHARACTERISTICS OF THE FLUVIAL FACIES AND PALAEOCHANNEL RECONSTRUCTION OF THE QUANTOU FORMATION IN THE SONGLIAO BASIN

The sandstones from the Quantou Formation consist of the most important oil-bearing horizons, and the channel sandbodies represent the main hydrocarbon reservoirs in the Songliao Basin. Therefore, the morphology and distribution of these sandbodies should be examined so as to facilitate oil and gas exploration. This paper deals in detail with sedimentary characteristics of the fluvial facies in the Quantou Formation on the basis of petrographic compositions, facies sequences, Well logs, seismic reflection, elementary geochemistry and spatial distribution of the channel sandbodies, and discusses the theoretical basis of palaeochannel reconstruction, the parameters involved and their calculations. The palaeochannel reconstruction has been made by the authors according to the measured sites of the fluvial sediments from the Quantouzhen section in Changtu and Weizigou section in Jiutai. The calculations obtained indicate that the former is thought to be characterized by the braided rivers, while the latter by the meandering rivers.