Professional Assessment of Petroleum Fiscal Regime Design and Its Impact on Investment Climate in Nigerian Marginal Fields Post-PIA 2021

The Petroleum Industry Act 2021 substantially restructured Nigeria's upstream fiscal regime, replacing the Petroleum Profits Tax and legacy royalty schedules with a Hydrocarbon Tax framework applicable to marginal field operators. This study professionally assesses the PIA 2021 fiscal provisions applicable to marginal field developments and evaluates their combined impact on the investment climate for marginal field operators in the onshore Niger Delta. A project economics modelling approach is adopted, constructing full-cycle discounted cash flow models for three representative marginal field development scenarios, differentiated by field size, development cost structure, and oil quality. Government take calculations are performed under both the legacy MIPA and the PIA 2021 fiscal regimes for direct comparison. Results indicate that the PIA 2021 Hydrocarbon Tax regime, combined with the revised royalty schedule and the Midstream and Downstream Infrastructure Fund obligations, increases effective government take by 4.8 to 7.2 percentage points compared to the legacy regime for marginal fields with reserves below 20 million barrels. Sensitivity analysis demonstrates that the revised fiscal terms render high-cost marginal fields economically marginal at oil prices below 55 USD per barrel. The study discusses the implications for farm-in and financing activity in marginal field blocks awarded under the 2020 licensing round and recommends specific tax relief provisions that would improve marginal field investment competitiveness while maintaining government revenue adequacy. Keywords: fiscal regime, PIA 2021, marginal fields, government take, Nigeria upstream.