Distal Fine-grain Shallow-water Delta Sedimentary Characteristics and Evolution: A Case from Badaowan Formation in the Central Junggar Basin

Key words: 
• Junggar Basin /
• Mosuowan area /
• Badaowan Formation /
• shallow-water delta /
• high light volume technology /
• sedimentary characteristics and evolution

Abstract: The climate was relatively wet, terrain was relatively flat, water power was relatively strong, the source of supply was adequate, lakeshore line relatively frequent changes of the Badaowan Formation sedimentary period of the Mosuowan area in the Central depression of Junggar Basin, which can form shallow-water delta. Sedimentary sandbody that is formed many positive cycle sedimentary sequences vertically mainly fine and medium-fine sandstone, which is the relatively fine grain size. The delta front has a wide distribution, long extension, large area and its planar configurations are major foliaceous, which are consist of compound sandbodies by multi-subaqueous distributary channel sandbody cut and superimposition. Thick, substantial and good connectivity subaqueous distributary channel sandbodies which are vertical superimposition and transverse cut each other are well developed, shale interbeds are relative thin and mouth bar sand body is not developed. The sandbody superimposition modes can be divided into different types, which is the major petroleum reservoir. On the whole, it formed the far-source, widespread, fine-grain shallow-water delta sedimentary system. The deposition and range of delta front and subaqueous distributary channel sandbody that are from two different source direction are different in different period, which is formed shallow-water delta that is mainly composed of wide composite channel sandbody finally.