Modified And Evaluation Of Nano-cellulose Fluids In Low Permeability Reservoirs

At present,the existing surfactants used in low-permeability reservoirs have environmentally unfriendly problems such as serious pollution of the formation and scaling of oil wells,and the polymer flooding applied in medium-high permeability reservoirs has technical problems of high injection pressure.As a stable and eco-friendly natural high molecular organic compound,nanocellulose(NC)has strong emulsifying ability and is environmentally friendly.It has been proposed for enhanced oil recovery(EOR)applications.In this paper,the "green" polymer flooding agent NC-SM was synthesized by etherification modification of NC with sodium 3-chloro-2-hydroxypropane sulfonate.The reaction conditions were optimized from four factors: temperature,p H,reaction time and sulfonating agent dosage.With the Turbiscan Lab Expert stability analyzer and contact angle tester,the mechanism of salt resistance and the mechanism of changing wettability of NC-SM were elaborated.Finally,Zetasizer Nano ZS laser nanometer particle size analyzer and microscope were used to study the influence of environmental factors on the stability of emulsion.The results showed that when the reaction temperature was 30 °C,the reaction time was 2.0 h,the p H was 7.5,and the ratio of the amount of sulfonating agent to the number of moles of nanocellulose was 0.3:1,the emulsification effect was the best.By changing the oil-water ratio,the NC-SM particle size and distribution can be controlled,and the size of the NC-SM can be adjusted,and both meet the requirements of low-permeability pore throat.It is believed that the addition of a sulfonate can hinder the intermolecular forces of the NC and prevent precipitation.At the same time,the salt ions can compress the diffusion double layer on the oil-water interface to enhance the stability of the emulsion.