Shale oil extraction Energy estimates that the "ex-situ" processing would be economic at sustained average world oil prices above $54 per barrel and "in-situ" processing would be economic at prices above $35 per barrel. These estimates assume a return rate of 15%. Royal Dutch Shell announced in 2006 that its Shell ICP technology would realize a profit when crude oil prices are higher than $30 per barrel ($190/m), while some technologies at full-scale production assert profitability at oil prices even lower than $20 per barrel ($130/m). To increase the efficiency of oil shale retorting and by this the viability of the shale oil
English wine cask units the traditional English volumes are commonly used in the wine and wine cooperage industries. Examples include a hogshead of , a barrique of (Bordeaux), a barrel of (Australia), a barrel of (Burgundy) and a puncheon of . The tun (, , Middle Latin: "") is an English unit of "liquid volume" (not weight), used for measuring wine, oil or honey. Typically a large vat or vessel, most often holding 252 wine gallons, but occasionally other sizes (e.g. 256, 240 and 208 gallons) were also used. In one example from 1507, a tun is defined as 240 gallons. The butt (from