Abstract
Shibata oilfield is located about 15 miles east of Niigata City. The subsurface Neogene sediments of the oilfield were studied to discover foraminiferal zonules. The Shibata Well No. 2 was investigated as the so-called "control well". The following four zonules are recognized in the oilfield, namely, (1) Rotalia 2-Nonion 5, (2) Cassidulina 1-Eponides 5, (3) Uvigerina 1, and (4) Cyclammina1 Zonules.
The correlation is based on the foraminiferal zonules, since electric Logs are not useful owing to the lapid facies change of rocks.
