Category Nuances for heavy_oil:

• difficult,
• raw,
• heavier,
• special,
• binding,
• organic,
• complex,
• viscous,
• industrial,
• heavy,
• carbonaceous,
• fluid,
• dirty,
• supplemental,
• rich,
• gaseous,
• ignitable,
• primary,
• extraneous,
• auxiliary,
• liquid,
• residual,
• base,
• inexpensive,
• gross,
• traditional,
• costly,
• inorganic,
• alternative,
• secondary,
• original,
• expensive,
• working,

Simple Categories for heavy_oil:

• substance,
• agent,
• hydrocarbon,
• fraction,
• fuel,
• mixture,
• fluid,
• oil,
• contamination,
• deposit,
• material,