Preparing these Consolidated Financial Statements in accordance with IFRS requires Management to make judgements on the basis of estimates and assumptions. These judgements affect the reported amounts of assets and liabilities and the disclosure of contingent assets and liabilities at the reporting date, and the reported amounts of revenues and expenses during the reporting period.

Management reviews the estimates and assumptions on a continuous basis, by reference to past experiences and other factors that can reasonably be used to assess the book values of assets and liabilities. Adjustments to accounting estimates are recognised in the period in which the estimate is revised if the change affects only that period or in the period of the revision and subsequent periods, if both periods are affected.

Actual results may differ the judgements, estimates made by the management if different assumptions or circumstances apply.

Judgments and estimates that have the most significant effect on the amounts reported in these Consolidated Financial Statements and have a risk of causing a material adjustment to the carrying amount of assets and liabilities are described below.


Engineering estimates of oil and gas reserves are inherently uncertain and are subject to future revisions. The Group estimates its oil and gas reserves in accordance with rules promulgated by the US Securities and Exchange Commission (SEC) for proved reserves. Oil and gas reserves are determined with use of certain assumptions made by the Group, for future capital and operational expenditure, estimates of oil in place, recovery factors, number of wells and cost of drilling. Accounting measures such as depreciation, depletion and amortisation charges and impairment assessments that are based on the estimates of proved reserves are subject to change based on future changes to estimates of oil and gas reserves.

Proved reserves are defined as the estimated quantities of oil and gas which geological and engineering data demonstrate with reasonable certainty to be recoverable in future years from known reservoirs under existing economic conditions. In some cases, substantial new investment in additional wells and related support facilities and equipment will be required to recover such proved reserves. Due to the inherent uncertainties and the limited nature of reservoir data, estimates of underground reserves are subject to change over time as additional information becomes available.

Oil and gas reserves have a direct impact on certain amounts reported in the Consolidated Financial Statements, most notably depreciation, depletion and amortization as well as impairment expenses. Depreciation rates on oil and gas assets using the units-of-production method for each field are based on proved developed reserves for development costs, and total proved reserves for costs associated with the acquisition of proved properties. Moreover, estimated proved reserves are used to calculate future cash flows from oil and gas properties, which serve as an indicator in determining whether or not property impairment is present.


Management assesses the useful life of an asset by considering the expected usage, estimated technical obsolescence, residual value, physical wear and tear and the operating environment in which the asset is located. Differences between such estimates and actual results may have a material impact on the amount of the carrying values of the property, plant and equipment and may result in adjustments to future depreciation rates and expenses for the period.

Goodwill is tested for impairment annually.

The recoverable amount of an asset or CGU 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 the risks specific to the asset or CGU. The estimated future cash flows include estimation of future costs to produce reserves, future commodity prices, foreign exchange rates, discount rates etc.


Certain conditions may exist as of the date of these Consolidated Financial Statements are issued that may result in a loss to the Group, but one that will only be realised when one or more future events occur or fail to occur. Management makes an assessment of such contingent liabilities that is based on assumptions and is a matter of judgement. In assessing loss contingencies relating to legal or tax proceedings that involve the Group or unasserted claims that may result in such proceedings, the Group, after consultation with legal and tax advisors, evaluates the perceived merits of any legal or tax proceedings or unasserted claims as well as the perceived merits of the amount of relief sought or expected to be sought therein.

If the assessment of a contingency indicates that it is probable that a loss will be incurred and the amount of the liability can be estimated, then the estimated liability is accrued in the Group’s Consolidated Financial Statements. If the assessment indicates that a potentially material loss contingency is not probable, but is reasonably possible, or is probable but cannot be estimated, then the nature of the contingent liability, together with an estimate of the range of possible loss if determinable and material, is disclosed. If loss contingencies can not be reasonably estimated, Management recognises the loss when information becomes available that allows a reasonable estimation to be made. Loss contingencies considered remote are generally not disclosed unless they involve guarantees, in which case the nature of the guarantee is disclosed. However, in some instances in which disclosure is not otherwise required, the Group may disclose contingent liabilities of an unusual nature which, in the judgment of Management and its legal counsel, may be of interest to shareholders or others.


Upon adopting of IFRS 11 the Group applied judgement when assessing whether its joint arrangements represent a joint operation or a joint venture. The Group determined the type of joint arrangement in which it is involved by considering it’s rights and obligations arising from the arrangement including the assessment of the structure and legal form of the arrangement, the terms agreed by the parties in the contractual arrangement and, when relevant, other facts and circumstances.