长链氧化胺黏弹性清洁压裂液及其流变特性

Viscoelastic Surfactant Fracturing Fluids Based on Long Chain Amine Oxide and Their Rheological Properties

本文获得了由长链氧化胺表面活性剂LAO与反离子盐复配形成的清洁胶束压裂液体系,并进一步研究了该体系流变性能、耐温性能及其相关影响因素。结果表明,LAO清洁压裂液最优组成为2%LAO+3%水杨酸钠(NaSal),该体系的耐温极限为120℃。该体系在110℃、170 s^(-1)下剪切1 h后,体系黏度可保持在30 m Pa·s以上。同时,该体系具有良好的携砂性能和明显的黏弹性、触变性和剪切变稀特性。破胶实验表明,在压裂液与原油体积比不大于40:1时,原油可使该体系顺利破胶,破胶液黏度小于3 m Pa·s。

A clean micelle fracturing fluids based on long chain amine oxide surfactant and counter-ion salts was obtained, and the rheological properties, thermal stability and related factors of the system were studied. The results showed that, the optimal formulation was 2% LAO ＋ 3% Na Sal, and the temperature resistance limit value of the system was of 120℃. The viscosity of the optimal system was kept above 30 m Pa·s after sheared for 1 hour at the shear rate of 170 s^（-1） at the temperature of 110℃. The rheological results showed that the 2%LAO ＋3% Na Sal fracturing fluids was characteristic of significant viscoelastic, thixotropic and shear thinning properties, and possessed excellent proppant-suspension property. Gel breaking experiments proved that when the volume ratio of the fracturing fluidings to the crude oil was lower than 40：1, the fracturing fluids could be broken completely after mixed with the crude oil, and the viscosity of the broken fluids was less than 3 m Pa·s.