羧甲基瓜尔胶压裂液的研究与应用

STUDY AND APPLICATION OF CARBOXYMETHYL GUAR FRACTURING FLUID

针对低渗透储层压裂增产改造的需要，开发应用了一种新型羧甲基瓜尔胶压裂液。利用红外光谱、滴定和黏度等实验法表征了羧甲基瓜尔胶的结构、羧甲基的取代度和相对分子质量，研究了羧甲基瓜尔胶的水溶性以及羧甲基瓜尔胶压裂液的性能，并和羟丙基瓜尔胶压裂液进行了对比分析。实验结果表明：羧甲基基团的引入导致瓜尔胶高分子链构象更加伸展，因此羧甲基瓜尔胶的水溶性更好，与羟丙基瓜尔胶相比较，水不溶物含量降低了一个数量级；羧甲基瓜尔胶的增稠效率更高，相同温度条件下羧甲基瓜尔胶压裂液增稠剂的含量比传统的羟丙基瓜尔胶压裂液增稠剂含量降低一半以上，破胶后残渣含量降低了70％以上。在海拉尔油田低渗透储层现场应用44口井111层，施工成功率98．9％，平均单井初期Et产液5．61t，13产油2．72t，取得了良好的增产效果。

Aiming at the demands of the fracturing stimulation in low-permeability reservoirs, a new type of carboxymethyl guar fracturing fluid is developed and applied. Through the application of infrared spectroscopy, titration, measurement of viscosity and other experimental methods, the structure, the substituted ratio, the molecular weight of carboxymethyl guar are characterized. The water solubility of carboxymethyl guar and the performance of the carboxymethyl guar fracturing fluid are investigated, and moreover the comparative analysis of carboxymethyl guar fracturing fluid and hydroxypropyl guar fracturing fluid is conducted. The experimental result shows that the introduction of carboxymethyl radical makes the conformation of the guar molecular chain more extended, therefore the water solubility of carboxymethyl guar is better. Compared with the hydroxypropyl guar, the content of water insoluble matter in carboxymethyl guar solution is decreased by one magnitude order. The thickening efficiency of the carboxymethyl guar is higher, and the content of the carboxymethyl guar fracturing fluid thickener has been decreased by half when it is compared with the content of hydroxymethyl guar fracturing fluid at the same temperature.After the gelout, the residue content is decreased by more than 70%. This carboxymethyl guar fracturing fluid has been applied in 44 wells in 111 layers of the low-permeability reservoirs in Hailar Basin, and the success rate of operation is 98.9%. The initial liquid production per well and the daily oil production rate are 5.61 t and 2.72 t respectively, and a relatively good stimulation effect is obtained.