Comparative Review of Surface and In-Situ Heavy Oil Upgrading Technologies: Performance, Economics, and Environmental Impacts

Considering that about ۷۰% of the world’s oil reserves are classified as unconventional hydrocarbons, a major part of which is heavy and ultra-heavy oil, upgrading these resources to produce refinery feedstocks has become a technical and economic necessity. Despite numerous studies on heavy oil upgrading technologies, most have been limited to qualitative analyses or have focused on specific process categories and lack an integrated quantitative comparison based on performance, economic, and industrial indicators. Aiming to fill this gap, this study presents a quantitative comparative framework that evaluates heavy oil upgrading technologies in three categories of surface, in-situ, and emerging processes based on four key indicators, including conversion efficiency, sulfur removal percentage, operating cost, and industrialization capability. The results show that the hydroprocessing process, with a conversion efficiency of ۹۰–۹۸% and a sulfur removal of ۹۵–۹۹%, provides the highest product quality but is associated with an operating cost of ۱۰–۲۵ /bbl and high hydrogen consumption. In contrast, coking with an efficiency of ۶۵–۷۵% and a sulfur removal of ۷۰–۸۵% has a cost of about ۸–۱۲ /bbl, while visbreaking with a cost of ۰.۲–۰.۵ /bbl provides only limited conversion (۵۰–۶۰%) and negligible sulfur removal. The CAPRI process, with an efficiency of ۱۵–۳۰%, further plays a complementary role in in situ improvement. Among the emerging technologies, HCAT (۹۰–۹۵%, ۲–۴ /bbl), HRH (۹۲–۹۷%, ۴–۶ /bbl) and EST (~۹۵%, ۲.۹–۷.۱ /bbl) show the best performance-to-cost ratio, while PetroSonic provides ۹۹% viscosity reduction and ۶–۱۰° API increase, and NexGen is in the industrial development stage with a cost of ۱–۳ /bbl and sulfur removal of ۶۰–۹۰%. In general, quantitative comparisons show that increasing conversion and sulfur removal are directly associated with increasing process rates and operating costs, such that hydroprocesses offer the highest product quality, while thermal processes fall into the lower cost range but with more limited upgrades. Emerging technologies are closing this techno-economic gap by reducing hydrogen intensity and improving performance-to-cost ratios, although their industrial maturity is not yet complete. The results show that no single technology simultaneously guarantees maximum quality, minimum cost, and minimal environmental impact, and the choice of technology depends on reservoir conditions, feed composition, and the project's economic-environmental objectives. This study provides a quantitative decision-making framework for selecting upgrading technologies under techno-economic and environmental constraints and can serve as a basis for designing hybrid strategies for the sustainable development of heavy oil resources.

کلیدواژه ها:

Heavy Oil Upgrading ، Techno-economic comparison ، Hydroprocessing ، Desulfurization ، Emerging upgrading technologies ، In-situ upgrading