阳离子羟丙基黄原胶的制备及性能评价

Preparation and Performance Evaluation of Cationic Hydroxypropyl Xanthan Gum

为改善黄原胶(XG)的各项性能,以3-氯-2-羟丙基三甲基氯化铵、环氧丙烷为改性剂与XG发生醚化反应,分别获得阳离子黄原胶(CXG)和阳离子羟丙基黄原胶(HCXG)。采用红外光谱、核磁共振和X射线衍射(XRD)等方法表征了产物的结构,研究了XG、CXG和HCXG溶液的流变性能及其作为压裂液的性能指标。红外、核磁以及XRD测试结果表明,阳离子醚化剂和羟丙基已成功接入XG。制备的HCXG的阳离子取代度平均值为0.3175%,羟丙基化程度为0.500%。HCXG溶液的流变性能和压裂液基液性能优于CXG和XG溶液。XG改性后的溶液黏度增加,0.4%HCXG溶液的表观黏度分别是XG、CXG溶液的6.27倍和2.27倍。XG改性后,溶液强度、屈服应力、黏弹性、耐温耐剪切性、携砂性和破胶性均明显提高。HCXG溶液流变性能和压裂液基液性能较好,可用于压裂液增稠剂。

In order to improve the properties of xanthan gum(XG),3-chloro-2-hydroxypropyltrimethylammonium chloride and propylene oxide were used as modifiers to etherify XG to obtain cationic xanthan gum(CXG)and cationic hydroxypropyl xanthan gum(HCXG). The structure of the product was characterized by infrared spectroscopy,nuclear magnetic resonance and X-ray diffraction(XRD). The rheological properties of XG,CXG and HCXG solutions and their performances as fracturing fluids were studied. The results of infrared,nuclear magnetic and XRD test showed that the cationic etherifying agent and hydroxypropyl group were successfully connected to XG. The prepared HCXG had an average degree of cationic substitution of 0.3175% and a degree of hydroxypropylation of 0.500%. The rheological properties of HCXG solution and the performance as fracturing fluid base fluid were superior to those of CXG and XG solutions. The viscosity of solution after XG modification increased. The apparent viscosity of 0.4% HCXG solution was 6.27 times and 2.27 times larger than that of XG and CXG solutions,respectively. After the modification,the solution strength,yield stress,viscoelasticity,temperature and shear resistance,sand carrying capacity and gel breaking property of XG were all significantly improved. The rheological property of HCXG solution and the performance as fracturing fluid base fluid were good. HCXG solution could be used for fracturing fluid thickener.