Study on Sedimentary Facies of Carboniferous Kalashayi Formation in the South of Tahe Oilfield

Key words: 
• Tahe oilfield /
• Kalashayi Formation /
• tidalflat facies /
• sedimentary facies /
• sedimentary model

Abstract: Based on the sedimentology, palaeontology and geochemistry, the sedimentary system of tidal flatlagoon were developed in the Carboniferous Kalashayi Formation in the south of Tahe oilfield from the studies of cores, well logs, palaeontology and geochemistry. The upper sandshale section of the Kalashayi Formation developed feathering crossbedding, wave bedding, lensing bedding, thin sand and mudstone interaction layers, low ration of sand to strata ,brackish water or vastsalinity creatures, all of them reflect an environment of tidal flat. In plane, the sand of the north of region of interest is coarser and contains gravels, that reflects there are rivers filling in. So this is a sedimentary system of tidal flat which has a nature of estuary. The Kalashayi Formation sandshale section was in intertidal zone, including tidal channel, sand flat, sandmud mixed flat, mouth bar microfacies. Upmudstone section includes darkgrey, greybrown and brown mudstone which occasionally contains thin pelitic siltstone，calcareous mudstone belt, developed parallel bedding, it is lagoonal facies. Finally, the sedimentary model of tidal flat with estuary has been established.