Impairment provisions for receivables from related parties and loans to related parties are recognised based on a forward looking expected credit loss model. The methodology used to determine the amount of the provision is based on whether there has been a significant increase in credit risk since initial recognition of the financial asset. For those for which credit risk has increased significantly, lifetime expected credit losses are recognised, unless further information becomes available contrary to the increased credit risk. For those that are determined to be permanently credit impaired, lifetime expected credit losses are recognised.

(b)           Non-financial assets

The carrying amounts of the Group's non-financial assets, other than deferred tax assets, are reviewed at each reporting date to determine whether there is any indication of impairment. If any such indication exists, then the asset's recoverable amount is estimated. For assets that have indefinite lives, the recoverable amount is estimated at each reporting date.

The recoverable amount of an asset or cash-generating unit is the greater of its value in use and its fair value less costs to sell. In assessing value in use, the estimated future cash flows are discounted to their present value using a pre-tax discount rate that reflects current market assessments of the time value of money and risk specific to the asset. For the purpose of impairment testing, assets are grouped together into the smallest group of assets that generates cash inflows from continuing use that are largely independent of the cash inflows of other assets or groups of assets (the "cash generating unit").

An impairment loss is recognised if the carrying amount of an asset or its cash generating unit exceeds its estimated recoverable amount. Impairment losses are recognised in the profit or loss.

3.9          Oil and gas production assets

Expenditures related to the construction, installation or completion of infrastructure facilities, such as platforms and pipelines, and the drilling of development wells, including delineation wells, is capitalised within oil and gas production assets. The initial cost of an asset comprises its purchase price or construction cost, any costs directly attributable to bringing the asset into operation, the initial estimate of the well asset retirement obligation, for qualifying assets, and borrowing costs.

Oil and gas production assets are depreciated using a unit of production method. The cost of producing wells is amortised over total proved and undeveloped oil and gas reserves of the field concerned, except in the case of assets whose useful life is shorter than 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 developed and undeveloped reserves of the relevant area. The unit-of-production rate calculation for the depreciation of field development costs takes into account expenditures incurred to date, together with sanctioned future development expenditure.

In accounting for a farm-out arrangement outside the exploration and evaluation phase, the Group:

·      Derecognises the proportion of the asset that it has sold to the farmee

·      Recognises the consideration received or receivable from the farmee, which represents the cash received and/or the farmee's obligation to fund the capital expenditure in relation to the interest retained by the farmor

·      Recognises a gain or loss on the transaction for the difference between the net disposal proceeds and the carrying amount of the asset disposed of. A gain is recognised only when the value of the consideration can be determined reliably. If not, then the Group accounts for the consideration received as a reduction in the carrying amount of the underlying assets

·      Tests the retained interests for impairment if the terms of the arrangement indicate that the retained interest may be impaired

The consideration receivable on disposal of an item of property, plant and equipment or an intangible asset is recognised initially at its fair value by the Group. However, if payment for the item is deferred, the consideration received is recognised initially at the cash price equivalent. The difference between the nominal amount of the consideration and the cash price equivalent is recognised as interest revenue. Any part of the consideration that is receivable in the form of cash is treated as a financial asset and is accounted for at amortised cost.