noun
extra heavy oil; heavy crude oil
Technical term used in the petroleum industry for crude oil with very high density and viscosity.
超重質油の精製には高度な技術が必要だ。
Refining extra heavy oil requires advanced technology.
重質油 is a broader term for heavy oil, while 超重質油 specifically refers to extra heavy oil with even higher density and viscosity.
Compound of 超 (chō, 'super, ultra'), 重質 (jūshitsu, 'heavy quality'), and 油 (yu, 'oil'). A modern technical term.