Depreciation is recognized in profit or loss on a straight-line basis over the estimated
useful lives of each part of an item of property, plant and equipment. Leased assets are
depreciated over the shorter of the lease term and their useful lives unless it is
reasonably certain that the Company will obtain ownership by the end of the lease term.
Drilling, exploration and other assets under construction are not depreciated.
The estimated useful lives for the current and comparative year, in accordance with the
instructions of the Parent Company, as approved by the Supreme Petroleum Council,
are as follows:
Asset category