技术经济学英文版演示文稿C41.ppt

4. CASH FLOW ANALYSIS 4.1 Basic Tax Structure 4.2 Domestic Agreements 4.3 International Contracts 4.4 Summary Similar to depreciation, once the current reserves are exhausted, an oil company will have to find a new reserve to maintain its existence. Therefore, as in the case of depreciation, the leasehold（租赁） costs are allowed to be recovered over a period till the reservoir is productive - its useful life. The method by which these costs are allowed to be recovered is called a depletion. The two most commonly used methods to recover the leasehold costs are a cost depletion and a percentage depletion. A cost depletion method is strictly a recovery of leasehold costs over a useful life of the reservoir. In contrast, a percentage depletion is a tax incentive(税收鼓励), where part of the gross income is waived from taxes irrespective of the leasehold costs. Both methods are discussed below. Cost Depletion Cost depletion is based on the number of units produced in a given year. It can be written as, (4.27) where (L) is the leasehold cost (including bonus, geophysical/ geological costs and other related costs required for finding reserves),(Dc) is the cumulative depletion up to a given year, (u) is the number of units produced in a given year and (R) is the remaining reserves at the end of a given year. Considering the uncertainties involved in estimating the remaining reserves, the value of the remaining reserves, (R) , can change reflecting any new knowledge gained over the period of production. Example 4.13 Leasehold costs associated with finding a new field are $l million. It is estimated that the field contains 200,000 bbls of recoverable oil. Assuming that the field has produced 30,000 bbls in the first year, 27,000 bbls in the second year and 20,000 bbls in the third year, calculate the amount of depletion this period using the cost depletion met