Submarine fan sediments in the middle submember of the third member of the Shahejie Formation in the Pucheng Oil Field, Henan

The middle submember of the third member of the Shahejie Formation in the Pucheng Oil Field, Henan is interpreted to be the submarine fan sediments, which are characteristic of both the tractional current and gravity flow-deposits. These sediments are dominantly fine-grained, and composed significantly of fine-grained sandstones and siltstones with normally-graded vertical sequences. Twenty lithofacies have been identified, on the basis of rock types, sediment grain sizes and sedimentary structures and textures, and vertically may be arranged into the following microfacies such as channel, interchannel, sheet sandstone, abyssal lake and bathyal lake, debris flow and slump deposits. A sedimentary model is presented in this study, showing the planar distribution of the vertical facies sequences and sedimentary microfacies in the study area.