Analysis Of Composition Interaction And Variation In The Interface Region For Surfactant Flooding

In the process of developing low-permeability oil and gas reservoirs and enhanced oil recovery EOR ,physics and chemical reaction occurred between fluid and fluid, fluid and solid at the interface region with the chemical injection into the oil layer, resulting in the destruction of the medium stable structure and fluid balancing property, and then producing the consequence of the reservoir dynamic systems much more complex than water/oil displacement dynamic systems [1].The visualized studies of water flooding resident oil in non-ionic surfactant combination system have shown that activation and mobilization of resident oil is a continuous evolution nonequilibrium irreversible process that oil transform from the static form to movement. Displacement process involving a variety of changes over time and space of the interface phenomena, which include fluid mass transfer, heat transfer, momentum transfer, phase characteristics and the interaction among capillary force,buoyancy and viscous force. Sometimes with the conduct of displacement, the significant structural changes of porous media is also accompanied. In this paper, the micellar aggregation phenomenon in the surfactant flooding and structural change and the entropy-driven process in the formation of surfactant micelles is analysised combining with chemical and thermodynamic theory. surfactant tail-based conversion free energy is the main factors that the total free energy of micelle formation is negative, providing the theoretical foundation for the selection of surfactant which matched with crude oil.