三偏磷酸钠交联黄原胶的制备及其溶液流变性

以三偏磷酸钠(STMP)为交联剂,合成了水溶性低交联度黄原胶(XG),依据其溶液粘度优化出了最佳合成条件;考察了电解质质量分数、pH值及温度对STMP交联黄原胶(简记为SP-c-XG)溶液流变性的影响,并与XG溶液进行了对比。 结果表明,在所研究的电解质(NaCl和CaCl₂)质量分数(0~5.0%)、pH值(2~11)和温度(20~70 ℃)范围内,SP-c-XG和XG溶液的流变曲线均为假塑型,符合Herschel-Bulkley模型;其屈服值、表观粘度和动力学模量随电解质质量分数增大均先下降后上升,而随pH值的升高先升高后降低,随温度升高而降低。 SP-c-XG和XG溶液具有相似的流变性,但与XG溶液相比,SP-c-XG溶液具有更高的屈服值和表观粘度,特别是具有更强的弹性和耐温性,在油田强化采油领域具有重要应用前景。

Synthesis of Sodium Trimetaphosphate Crosslinked Xanthan Gum and Rheological Properties of Its Aqueous Solution

A water-soluble weakly crosslinked xanthan gum(XG) was synthesized using sodium trimetaphosphate(STMP) as a crosslinker, and the synthesis conditions were optimized based on the viscosity of the STMP crosslinked XG(denoted as SP-c-XG) solutions. Effects of electrolyte(NaCl and CaCl₂) mass fraction(0~5.0%), pH(2~11), and temperature(20~70 ℃) on the rheological properties of the SP-c-XG solutions were investigated and compared with those of XG solutions. The results show that, under the studied conditions, the rheological curves of both SP-c-XG and XG solutions are pseudoplastic and can be described by Herschel-Bulkley model. The yield stress, apparent viscosity and dynamic moduli of the SP-c-XG and XG solutions initially decrease and then increase with increasing electrolyte concentration, but they initially increase and then decrease with increasing pH. Increasing temperature results in a decrease in these rheological parameter values for both SP-c-XG and XG solutions. The rheological properties of the SP-c-XG solution are similar to those of the XG solution. However, compared with the XG solution, the SP-c-XG solution exhibits higher yield stress and apparent viscosity, especially stronger elasticity and temperature resistance, indicating its use potential in enhanced oil recovery.