@Article{ee.2026.081442,
AUTHOR = {Sijin Zhu, Jian Guan, Songyan Li},
TITLE = {Research of Chemical Additive-Assisted CO<sub>2</sub> Huff-n-Puff for Enhanced Heavy Oil Recovery},
JOURNAL = {Energy Engineering},
VOLUME = {},
YEAR = {},
NUMBER = {},
PAGES = {{pages}},
URL = {http://www.techscience.com/energy/online/detail/26650},
ISSN = {1546-0118},
ABSTRACT = {Carbon Capture, Utilization and Storage (CCUS) is a critical decarbonization technology, and CO<sub>2</sub>-enhanced oil recovery (CO<sub>2</sub>-EOR) effectively combines CO<sub>2</sub> geological storage with crude oil production, especially for high-difficulty heavy oil reservoirs. To overcome viscous fingering and early gas channeling in conventional CO<sub>2</sub> huff-n-puff, this study focused on chemical additive-assisted CO<sub>2</sub> huff-n-puff for cold heavy oil production in the Gudong reservoir. Through screening and optimization, 0.5% HY-2 foaming agent and 0.5% SR-1 viscosity reducer were identified as optimal, showing stable performance and strong synergy with CO<sub>2</sub>. High-temperature high-pressure experiments indicated the suitable CO<sub>2</sub> injection volume is 0.15–0.2 PV, the optimal injection sequence is chemical solution followed by CO<sub>2</sub>, and the technology is applicable for crude oil viscosity below 3000 mPa·s. The 0.5% HY-2 + 0.5% SR-1 system enhanced oil recovery to 45.07%, 14.4% higher than pure CO<sub>2</sub> huff-n-puff, while the 0.5% SR-1 single-agent scheme achieved 42.13% recovery with better economics. The main mechanisms include emulsification and viscosity reduction, gas mobility control, and expanded sweep efficiency, supplemented by CO<sub>2</sub> dissolution, oil swelling, and elastic drive. Field tests in four wells showed an average daily oil increase of 2.7 t per well and a total incremental oil of 1748.6 t, with a CO<sub>2</sub> storage rate of 80.4% and an input-output ratio of 8.02:1. This study verifies the technical and economic feasibility of chemical-assisted CO<sub>2</sub> huff-n-puff, providing support for its field application and a practical route for heavy oil EOR and carbon reduction coordination.},
DOI = {10.32604/ee.2026.081442}
}