Abstract
As income from petroleum sales is typically lower in smaller fields compared to that in larger oilfields, this will lead to constrained budgets and cash flows for new investments. The planning and scheduling of field development for a small mature oil reservoir are crucial, as the feasibility of the extended field development project will determine whether to continue or terminate the oil production. Thus, this study aims to assess the performance and feasibility of tertiary phase recovery through HPAM polymer flooding in a small mature waxy oil, selecting the Maesoon oilfield in the Fang basin as the case study. The analysis involves calculating capital and operating costs associated with polymer injection, while considering revenue from oil sales to evaluate key economic indicators for each development project. This study also examined the impact of key planning and scheduling parameters, such as polymer concentration, injection rate, and timing, on tertiary polymer injection to observe their effect on oil recovery mechanisms during polymer flooding. The findings highlight that the optimized value of operating parameters is highly dependent on injection fluid properties and formation sequence characteristics, as these affected the oil recovery mechanism, injectivity, and sweep efficiency during polymer flooding. HPAM polymer flooding proved to be a suitable enhanced oil recovery (EOR) strategy for the Maesoon oilfield in the final 10-year of production, resulting in significantly higher incremental oil recovery and the highest project net present value (NPV) of around 11.65 million USD compared to natural recovery (0.95 million USD) and pure waterflooding (9.51 million USD) at a base crude oil price of 70 USD/bbl. The break-even crude oil sale price for the EOR project was approximately 20.2 USD/bbl, suggesting its viability for implementation in this oilfield if the present crude oil price remains significantly above this threshold. Although further laboratory and pilot studies are required for oil recovery verification, this research can serve as a guideline for small oilfields to choose suitable development methodologies and operating parameters to maximize project returns.