Royal Dutch Shell plc (2010)
NOTES TO THE CONSOLIDATED FINANCIAL STATEMENTS [extract]
2 ACCOUNTING POLICIES [extract]
PROPERTY, PLANT AND EQUIPMENT AND INTANGIBLE ASSETS [extract]
[B] Depreciation, depletion and amortisation
Property, plant and equipment related to hydrocarbon production activities are depreciated on a unit-of-production basis over the proved developed reserves of the field concerned, except in the case of assets whose useful life differs from the lifetime of the field, in which case the straight-line method is applied. Rights and concessions are depleted on the unit-of-production basis over the total proved reserves of the relevant area. Where individually insignificant, unproved properties may be grouped and amortised based on factors such as the average concession term and past experience of recognising proved reserves.
Other property, plant and equipment are depreciated on a straight-line basis over their estimated useful lives, which is generally 30 years for upgraders, 20 years for refineries and chemical plants and 15 years for retail service station facilities. Major inspection costs are amortised over the estimated period before the next planned major inspection (three to five years). Property, plant and equipment held under finance leases are depreciated over the lease term.
Goodwill is not amortised. Other intangible assets are amortised on a straight-line basis over their estimated useful lives which is generally five years for software and up to 40 years for other assets. Estimates of the useful lives and residual values of property, plant and equipment and intangible assets are reviewed annually and adjusted if appropriate.