Sedimentary microfacies of the fluvial sandstones: an example from the sandstones in the Guantao Formation on the northern slope of the Chengdong oilfield in the Jiyang depression, eastern China

Exemplied by the sandstones in the Guantao Formation on the northern slope of the Chengdong oilfield in the Jiyang depression, eastern China, the sedimentary microfacies of the fluvial sandstones are described in detail in the present paper. These sandstones in the fluvial facies may be group into three sedimentary facies including the meandering, anastomosed and braided stream facies, and seven sedimentary microfacies. The approaches of the vertical and horizontal changes of the sedimentary microfacies are mostly based on the data on the individual well sections and inter well sections in combination with relevant seismic data, resulting in the construction of the plans showing the distribution of the sedimentary microfacies during the deposition of different sandstone groups in the study area.