Relative permeability characteristic of nano-oil displacement agent and its effect on the development of shale oil
Nanotechnology has a wide application prospect in unconventional oil and gas development and is expected to become a new generation of disruptive development technology.The relative permeability needs to be studied as a vital flow characteristic of displacement and imbibition.The relative permeability experiments with shale core were conducted for different flooding media,including nano-agent,surfactant,etc.The results show that:1)The characteristic n value of nano-oil displacement agent decreased significantly,which is beneficial to improve oil-water fluidity and reduce injection pressure;2)The relative permeability of the endpoint of water phase with low concentration nano-agent is significantly higher than that of formation water,the flowability of aqueous solution with low concentration nano-agent is stronger;3)The two-phase area of the nano-oil displacement agent is 8.8%more than that of oil-water,and the range is small,so it is important to improve the development mode to improve the displacement efficiency further;4)The displacement efficiency can be significantly increased from 36.67%to 74.67%by the combination of displacement and imbibition;5)The development effect can be further improved by cycle displacement,and the displacement efficiency is 14.1%higher than continuous displacement(injection volume multiple 0.478 PV).The research result is important for development mode optimization to supplement energy,oil production stability,and enhanced oil recovery of shale oil reservoirs.