Study On New Viscoelastic Gemini Micelle-Air Foam System And Its Rheological Properties

In order to develop clean air foam fracturing fluids system,a automatically thickening without salts and high-temperature resistant agent-long chian Gemini surfactant(FL-25)and two compounded foam agents(F1-1and FX),were prepared in this work.The rheological properties of FL-25 fracturing fluids and new viscoelastic Gemini micelle-air foam were further investigated.The rheological properties of non-crosslinking compounded clean fracturing fluids were also investigated.The compounded clean fracturing fluids consists of FL-25 and guar gum,xanthan gum.The main conclusions were listed below:1)The long alkyl chian Gemini cationic surfactant FL-25 was prepared with Erucamidopropyl Dimethylamine using "two steps in one batch".The factors such as solvent species and usoage,reaction temperature,reaction time on the performances of viscoelastic surfactant fracturing fluid were confirmed.The optimum synthetic conditions were found.2)The long alkyl chian Gemini surfactant FL-25 can self-assembly into worm-like viscoelastic fluid in aqueous solution without adding counter-ionic salts.The apparent viscosity of the 3.0%FL-25 worm-like viscosity fluid at 170s-1 can remain approximately 69.64 mPa·s at 110? for 90 minutes.3)The viscoelastic FL-25 fracturing fluids at different concentration were characterized with shear thinning property,viscoelasticity,thixotropy,proppant-carry property.The flow curves can be well described by CROSS Model;the storage modulus G' always prevails over the loss modulus G" in the whole frequicy range.The sedimentation experiments of singe proppant show that 3.0%FL-25 fracturing fluids can carry proppant at 100?.4)New viscoelastic Gemini micelle-air foam system and its foaming condition were achieved.The foam system possesses thixotropy and shear thinning property.5)The non-crosslinking compounded fracturing fluids,such as,2.0%FL-25+0.2%HPG?2.0%FL-25+0.2%XG?2.0%FL-25+0.2%HXG,can endure high temperature at 100?.If the concentration of FL-25 increases to 3.0%,the fracturing fluids can endure temperature at 120?,and its viscosity can remain 30.77 mPa·s.The results in this work are expected to enrich and develop the high-temperature clean fracturing fluids system and its application,and provide rheological basis for clean air foam fracturing fluids.