The On'nagawa Formation in Akita Sedimentary Basin is composed of siliceous mudstone and volcaniclastics. The volocaniclastic facies have been productive reservoirs of oil and gas fields in the Neogene Akita Basin, North Japan. The mudstone facies have been recognized to be potential source rocks for hydrocarbons pools in the reservoirs. After a long period of oil and gas production in the basin, a potential exploration concept of a new play in the siliceous rocks is required to keep the productivity of the basin.
This study reports a basic description of physical properties of the siliceous mudstone facies in order to provide a basis for the idea of shale play in the On'nagawa Formation. Wireline logs (GR, Δt, ρb) are basic data for our description of the physical rock properties as well as descriptions of cutting lithology.
