Development And Performance Evaluation Of A New Type Of Acid Thickener

Acidification is one of the most important stimulation in gas and oil,reservoirs, and viscosifier is a more important additive, which is used to inhibit acidification rate. A kind of more effective viscosifier can improve the viscosity of acid solution, reducing the mass transfer velocity of hydronium H~+ towards the rocks surface, thereby decrease the filtrate loss of acid solution and the reaction rate between acid and salt, lengthen the distance of acid penetration.This paper first reviews the development and the existing problems of polymeric viscosifier. On this basis, we take into account to use PAM as the molecular backbone, introducing DMDAAC as cation group, DMAM as the hydrophobic group to synthesis hydrophobic modified cationic polyacrymide with good viscosity performance viscosifier. Terpolymers of P(AM-DMDAAC-DMAM) were synthesized by free radical copolymerization in opposite phase emulsion. The effect of total concentration of monomers, initiator concentration, initiator ratio, reaction temperature and reaction time which affect intrinsic viscosity of polymers of tripolymers and the reaction conversion was discussed.The final results indicate that under the following conditions that kerosene is used as oil phase ; the ratio of oil to water in volume is 1:5 ; emulsifier is complex of Tween-60, Span85 ; the proportion of usage is 10% ; monomers ratio of AM: DMAM: DMDAAC is 0.80:0.05:0.15 ;the total concentration of monomers is 30wt%; the reaction temperature is 45 ℃ ; reaction time is 8 hours; the pH is 7 the cationic polymeric viscosifier of higher intrinsic viscosity can be produced. The results of the IR analysis under the above conditions show that this kind of Terpolymers contains antitemperature and resisting salts designed in this study. In this study, the thermal stability of this viscosifier in the acid is 80.23%. its shear stability is 86.4%, which shows that this kind of the viscosifier own better thermal stability and shear stability. The test of compatibility shows that this kind of viscosifier can be compatible with the often-used agents in the acid in a better way. The results of contrastive experiment indicates that the functions of this viscosifier composed in this study are closer to those of the similar products in China. It can solve the problems, namely, the problems of antitemperature and resisting salts occurring in using viscosifier in the acid. It also broaden the field of applying the this viscosifier in the acid to the process of enhance product in oil .therefore it has a brighter development future.