Study On Rheological Properties Of Modified Cellulose Solutions And Rheokinetics Of Crosslinking Gelation Process

In order to develop new fracturing fluid thickeners, carboxymethyl hydroxyethyl cellulose (CMHEC), epichlorohydrin (EPIC) and trimetaphosphate (STMP) were used as the materials in this study to investigate the preparation processes of two kinds of crosslinking modified cellulose. N, N-dimethyl dodecyl amine was used in the preparation process of hydrophobically modified cellulose. The rheological properties, shear crosslinking rheokinetics and drag reduction properties of the modified cellulose solutions were further studied, and rheokinetics equations were established. The main conclusions are as follows:1) Water soluble epichlorohydrin crosslinked carboxymethyl hydroxyethyl cellulose (EPIC-CMHEC) and trimetaphosphate crosslinked carboxymethyl hydroxyethyl cellulose (STMP-CMHEC) were obtained, and suitable reaction conditions were determined. Hydrophobic intermediate DE was obtained from the reaction of epichlorohydrin and N,N-dimethyl dodecyl amine to further synthesize hydrophobically modified cellulose DE-CMHEC. Suitable reaction conditions were determined.2) The investigation of rheological properties of cellulose solutions shows that the viscosity, elasticity, thixotropy and temperature resistance of the modified cellulose solutions are better than those of CMHEC solution. The flow curves can be described by the Cross equation of generalized Newtonian fluid.3) The investigation of shear crosslinking processes of modified cellulose solutions shows that crosslinking agent and pH regulator dosage, shear rate and temperature can influence isothermal and temperature increasing crosslinking processes. The 4-parameter shear crosslinking rheokinetics equation was proved to describe the viscosity-time curves.4) The study of drag reduction properties of cellulose solutions shows that the three modified cellulose solutions possess good drag reduction performances with the largest drag reduction rate of more than 70% when the concentrations are from 0.08% to 0.15%(wt%), which can be expected to be applied as drag reducing agent for fracturing slick-water.This paper studied new thickeners for fracturing fluids, and provided rheological basis for further application.