August OSP for propane is $590 per tonne Price for butane set at $570 a tonne RIYADH: The Saudi Arabian Oil Co., also known as Saudi Aramco, on Wednesday raised the official selling price for propane by $10 per tonne and butane by $5 a tonne from the previous month, according to an official statement. The August OSP for propane is $590 per tonne, while the price for butane has been set at $570 a tonne. Propane and butane are types of liquefied petroleum gas with different boiling points. LPG is mainly used as a fuel for cars, heating and as a feedstock for other petrochemicals. Aramco’s OSPs for LPG are used as a reference for contracts to supply the product from the Middle East to the Asia-Pacific region.