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
Barrel of oil equivalent 10 BTU equals 6.1178632 × 10 J, about 6.1 GJ (HHV), or .) The value is necessarily approximate as various grades of oil and gas have slightly different heating values. If one considers the lower heating value instead of the higher heating value, the value for one BOE would be approximately 5.4 GJ (see ton of oil equivalent). Typically or 58 CCF are equivalent to one BOE. The USGS gives a figure of 6,000 cubic feet (170 cubic meters) of typical natural gas. A commonly used multiple of the BOE is the kilo barrel of oil equivalent (kboe or kBOE),