有机盐抑制黏土水化膨胀应用

Application of Inhibiting Clay Hydration and Expansion by Organic Salt

黄秋伟 许江文 王新河 胡广文 陈超峰

HUANG Qiu-Wei XU Jiang-Wen WANG Xin-He HU Guang-Wen CHEN Chao-Feng

考察了氯化钾在黏土、石英砂表面的吸附量以及甲酸钾和甲酸铵在蒙脱土表面的吸附量，对比研究了有机盐OS500A（含甲酸钾75%）溶液、OS500B（含甲酸铵75%）溶液、氯化钾溶液和清水抑制黏土水化分散的情况。结果表明：无论是氯化钾溶液还是有机盐甲酸钾或甲酸铵溶液，随着盐溶液浓度增大，盐吸附量逐渐增加。当氯化钾溶液质量浓度为160 g/L时，氯化钾在蒙脱土、高岭土和石英砂表面的最大饱和吸附量分别为5.6、2.06和1.57 mg；当甲酸盐溶液质量浓度接近100 g/L时，蒙脱土对甲酸钾、甲酸铵的最大吸附量分别为5.51和5.42 mg。蒙脱土对有机盐的吸附较易达到饱和，其饱和最大吸附量与无机盐相当。粒度分析结果表明，抑制黏土水化分散能力的强弱顺序为：甲酸铵（OS500B）>甲酸钾（OS500A）> 5%氯化钾>清水。用煤油改变岩石表面的润湿性，有助于提高有机盐抑制黏土水化膨胀的作用。用氯化钾复配甲酸盐体系在阜东地区现场应用10口井，保护效果明显。

The adsorption capacity of potassium chloride on the surface of clay and quartz sand, and that of potassium formate and ammonium formate on the surface of montmorillonite was studied. The inhibition effect of organic salt solution OS500A (containing 75% potassium formate) and OS500B (containing 75% ammonium formate), potassium chloride solution and clean water on the hydration and dispersion of clay was compared. The results showed that for potassium chloride solution, potassium formate solution and ammonium formate solution, the adsorption capacity of salt increased gradually with increasing concentration of salt solution. When the mass concentration of potassium chloride solution was 160 g/L, the maximum adsorption capacity of potassium chloride on the surface of montmorillonite, kaolinite and quartz sand was 5.6, 2.06 and 1.57 mg, respectively. When the mass concentration of formic acid brines approached 100 g/L, the maximum adsorption capacity of potassium formate and ammonium formate on the surface of montmorillonite was 5.51 and 5.42 mg. The adsorption of organic salt on montmorillonite was easily saturated, and its maximum adsorption capacity was equal to that of inorganic salt. The result of grain size analysis showed that four solution were arranged according to their inhibition ability on the hydration and dispersion of clay in following order: ammonium formate (OS500B)>potassium formate (OS500A)>potassium chloride 5%>clean water. If the wettability of rock surface was changed by kerosene, it would improve the inhibition effect of clay dilating by organic salt. The compounded system of potassium chloride and formic acid brines was applied in 10 wells of Fudong region，the protection effect was obvious.