Hydrogen-bond-modulated flowable weak gel for EOR in ultra-high temperature and ultra-high salinity fracture-cavity ordinary heavy oil reservoirs
Xue M. Chen L. Chen H. Fu L. Bai Y. Lv W. Hou B. Riazi M.
20 November 2025Elsevier B.V.
Colloids and Surfaces A: Physicochemical and Engineering Aspects
2025#725
This paper presents a novel weak-gel oil flooding agent for ultra-high temperature and ultra-high salinity fracture-cavity ordinary heavy oil reservoirs and evaluates its performance. The agent has changed the characteristic that the traditional gel material can hardly flow. At 130 °C and 22 × 104mg/L, the viscosity is 750mPa·s and almost not affected by shear. After aging at 130 ℃ for 50d, the viscosity retention rate reached 83.1 % and the dehydration rate was only 4 %. Rheological tests showed that the addition of guanidine Hydrochloride (GuHCl) greatly improved the flow performance of the system. Through cryo-scanning electron microscope (Cryo-SEM) and X-ray photoelectron spectroscopy (XPS) analysis, it was inferred that the -CONH2 on the polymer backbone was protected by forming hydrogen bonds with GuHCl to prevent dehydration condensation with hydroxymethylated hydroquinone, which reduced the crosslinking density and enhanced the flow performance of the system. In the fracture model, when crude oil has a viscosity of 400mPa·s and the fracture scale is 8 mm, the weak-gel flooding agents recovery rate reaches 68.54 %, 49.32 % higher than water flooding and 28.37 % higher than polymer flooding. In the fracture-cavity model, with a cave volume of 25 mL and crude oil viscosity at 400mPa·s, its recovery rate is 65.51 %, 54.51 % and 48.38 % higher than water and polymer flooding respectively. This shows the agents good performance in such models, offering guidance for enhanced oil recovery in ultra-high temperature and ultra-high salinity fractured-cavity heavy oil reservoirs.
Enhance oil recovery , Fractured-cavity reservoir , GuHCl , Oil-flooding agent , Ordinary heavy oil , Weakly gel
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School of Petroleum Engineering, Yangtze University, Wuhan, 430100, China
Hubei Key Laboratory of Drilling and Production Engineering for Oil and Gas, Wuhan, 430100, China
School of Petrochemical Engineering, Changzhou University, Changzhou, 213000, China
School of Petroleum and natural Gas Engineering, Changzhou University, Changzhou, 213000, China
School of Mining and Geosciences, Nazarbayev University, Astana, Kazakhstan
School of Petroleum Engineering
Hubei Key Laboratory of Drilling and Production Engineering for Oil and Gas
School of Petrochemical Engineering
School of Petroleum and natural Gas Engineering
School of Mining and Geosciences
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