ABSTRACT
Tight oil has become an important strategic replacement resource.Aiming at the problem of “water can not be injected, oil can not be extracted” for tight oil reservoir development, a in-situ nano permeability-increasing agent(in-situ NPIA, < 300 nm) with core-shell structure was prepared. The in-situ NPIA has a “small size effect”, can significantly reduce the injection start-up pressure gradient, and it can release of the hydrophobic “core” when exposed to crude oil, inverting the “large oil” into “small oil”, greatly improving the oil liquidity, and eventually increasing the EOR. It also showed excellent interfacial tension and lower injection pressure compared with water. The low-field nuclear magnetic resonance (NMR) flooding (0.02 mD core) experiments show that, compared with water flooding, in-situ NPIA can increase the oil displacement efficiency by 19.7 %. So, It may be used to help develop the unconventional resources such as tight oil/gas, shell gas and oil etc.
