Study on in-depth profile modification of nano-biomass water dispersant

To address the issues of limited deep migration capacity, low utilization efficiency, and inadequate environmental sustainability of microspheres, a nano-biomass water dispersant was synthesized using surface-modified nanocellulose (12-25 wt%) as the primary component. The dispersant was systematically evaluated for its temperature and salt tolerance, as well as its pore-throat blocking capabilities, under simulated reservoir conditions. Results indicate exceptional stability and swelling behavior in extreme environments. The particle size increased from <100 nm to 1–10 μm within 7 days at 150 °C in simulated formation water (118,913 mg/L), demonstrating long-term stability under hypersaline conditions. Unlike conventional flooding methods, this nano-biomass system introduces an innovative synchronous displacement mechanism. Rather than adjusting first and then flooding, it combines temporary pore-throat blocking with oil displacement, improving the diversion rate in low-permeability zones by 10%. The dispersant also exhibits superior oil-water interfacial activity, achieving an interfacial tension (IFT) of 10 −2 mN/m at a 0.3 wt% concentration through in situ emulsion formation upon contact with crude oil. Field trials in the Chang Qing Oilfield confirmed its adaptability to high-temperature and high-salinity reservoirs. Owing to its unique thermal stability and salinity resistance, this eco-friendly material represents a promising alternative to synthetic polymers for harsh reservoir conditions.