This paper has investigated the impact of petroleum contracts on Iranian oil production trend. At first, effect of these contracts on a sample reservoir has evaluated and then by using the obtained results, Iranian oil production trend has estimated. Forecasting oil production trend from sample reservoir is obtained by applying a Mixed Integer Non-Linear Programing (MINLP) which maximizes Net Present Value of the producer and considering physical, economical and contractual aspects. Then, by applying Multiple Lambda Hubbert Model and using obtained results, effect of petroleum contracts on Iranian oil production trend has investigated for two different periods.

Based on obtained results for optimized production of the sample reservoir, in the case of existing long-term contracts with International Oil Company (IOC) production rate is more than the case which National Iranian Oil Company (NIOC) controls oil production. Obtained results show that in the period which IOCs have had control of oil production, due to their incentive for maximizing profit, production rate is higher than potential production. While in the period of developing oilfields by signing Pure Service Contracts which production management would be conducted by NIOC, due to lack of technology and insufficient investment, actual production is lower than potential production.