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Diatom Biostratigraphy of the Upper Miocene to Pliocene in the Yufutsu oil and gas field, Hokkaido, Japan

2004; Japanese Association for Petroleum Engineers; Volume: 69; Issue: 3 Linguagem: Inglês

10.3720/japt.69.291

1881-4131

平松 力,

Diatoms and Algae Research

Diatom biostratigraphy was examined for the upper Miocene to Pliocene sequence distributed in the Yufutsu oil and gas field located in southern central Hokkaido, Japan.The Denticulopsis praedimorpha and Denticulopsis dimorpha Zones were recognized in thin volcanic reworked sediment with glauconite, which overlies just above the Takinoue volcanics oil reservoir. The result indicates that the condensed glauconite bed had been formed for a long time, from the end of Takinoue volcanic activity through the D. dimorpha Zone.Siliceous sediments overlaying the glauconite bed are correlated to the upper part of the Thalassionema schraderi and Rouxia californica Zones. The siliceous sediment is unconformably covered by sandy sediment. Its basal part is correlated to the Neodenticula koizumii-Neodenticula kamtschatica Zone. The N. kamtschatica Zone is completely missing in the field whereas it is thickly developed at the Yufutsu-oki wells located about 20km offshore.Based on the diatom biostratigraphy and interpretation of seismic profiles, the condensed glauconite bed is correlated to the middle to upper Miocene Fureoi and Karumai Formations. The interval of "the Biratori and Karumai Formations" by several authors in the field is correlative to the upper Miocene Nina Formation typically distributed along the Sarugawa river near the Biratori city. "The Nina Formation and Quaternary System" in the field is correlated to upper Pliocene and Quaternary.