TY - EJOU
AU - Sun, Yongquan
AU - Yan, Wenxin
AU - Lv, Guangzhong
AU - Kong, Chuixian
AU - Wu, Zhonghui
AU - Hao, Yongmao
TI - Experimental Investigation of CO2–Gel–Nanowater Multi-Media Flooding for Enhanced Oil Recovery in Tight Reservoir
T2 - Energy Engineering
PY -
VL -
IS -
SN - 1546-0118
AB - Tight oil reservoirs are prone to severe gas channeling during CO2 flooding, resulting in low sweep efficiency and significantly limiting oil recovery. In this study, a multi-medium composite flooding system involving CO2-nanowater-gel-water was proposed and its enhanced oil recovery potential was systematically investigated through series and parallel long-core flooding experiments. The experimental results indicate that the recovery factor of CO2 flooding in homogeneous cores can reach 62.54%, primarily driven by the extraction of light and intermediate hydrocarbon components, as well as the effects of crude oil swelling and viscosity reduction. In fractured cores, by adopting the optimal injection sequence of gel + water + nanowater, the final recovery factor reached 67.66%. The high-strength steric hindrance and plugging effect of the gel effectively suppress gas channeling in fractures and high-permeability layers, forcing CO2 to divert into unswept zones. Simultaneously, the nanowater further enhances microscopic displacement efficiency by reducing oil-water interfacial tension and improving wettability, achieving a synergistic effect of deep profile control and efficient displacement. In multi-layer parallel experiments, the recovery factors of cores with different permeabilities were all improved, with the gel + water + nanowater system yielding a recovery increment of 46.60%. This study provides critical technical support and a strategic reference for the efficient development of tight oil reservoirs.
KW - Multi-media combination; CO2 flooding; gel; long core
DO - 10.32604/ee.2026.077987