Council of Petroleum Accountants Societies (COPAS) provides two methods that petroleum companies may use to accounting their business transactions. These method are (i) Successful efforts and full cost methods and (ii) Tax method. Upstream, the accumulated capitalized costs from Exploration & Evaluation (E&E) and development phases are amortized over the expected total production using a Units Of Production (UOP) basis. Downstream, depreciation is allocated on a systematic basis using either the straight-line method or the throughput method. IFRS has a specific requirement for 'component' depreciation, as described in IAS 16 Required: a) Write brief notes, illustrating with examples, on i. Successful efforts and full cost methods ii. Tax method