柠檬酸羟基铝防膨剂的制备及其性能评价

Preparation and Evaluation of Citric Acid Hydroxyl Aluminum Anti-Swelling Agent

以柠檬酸、Al Cl36H2O、丙三醇和Na OH为原料,采用先络合后中和的方法制备了柠檬酸羟基铝防膨剂(THL-1),分析了防膨机理。THL-1中含有大量的多核羟桥铝离子,多核羟桥铝离子带有大量正电荷,对钠基膨润土表面的负电荷具有较强的吸附作用。考察了在无Al(OH)3沉淀生成的条件下,柠檬酸与Al Cl36H2O的配比关系,研究了Al Cl36H2O含量及p H对防膨率的影响,考察了THL-1的防膨效果、耐水冲洗性能及其与压裂液的配伍性等。实验结果表明,当Al Cl36H2O含量大于17.5%(w)时,THL-1对钠基膨润土的防膨率大于90%,且趋于平缓。THL-1的防膨率与KCl相当,达93.6%,但耐水洗性能比KCl好,具有长期稳定钠基膨润土的作用;与TDC-15等阳离子聚合物型黏土稳定剂相比,THL-1具有防膨速率快、防膨率高、防后水质清等优点,且与压裂液具有良好的配伍性。

A anti-swelling agent, citric acid hydroxy aluminum （THL-1）, was synthesized from citric acid, aluminum chloride, glycerol and sodium hydroxide through first complexation and then neutralization, and the mechanism of its anti-swelling was analyzed. THL-1 contains a lot of polynuclear olation aluminum ions with a large number of positive charges which have strong adsorption to negative charges on sodium bentonite. The mass ratio of citric acid to AlCl3 · 6H2O without the formation of Al （OH） 3 precipitate, the effects of AlCl3 · 6H2Ocontent and pH on the anti-swelling rate, the anti-swelling effect of THL-1, its scour resistance, and its compatibility with fracture fluids were investigated. The experimental results showed that, when the AlCl3 · 6H2O content was higher than 17.5% （w）, the anti-swelling rate of THL-1 to sodium bentonite was more than 90% and leveled off. The anti-swelling rate of THL-1 is similar to that of KCl but its scour resistance is better and it has a long-term stabilization for sodium bentonite. Compared to TDC-15 and other cation polymer clay stabilizers, the anti-swelling of THL-1 is fast, its anti-swelling rate is high, the water after the anti-swelling is clear and its compatibility with other fracture fluids is good.