Comparative study on the use of three types of clay stabilizers in acidification

From the perspective of clay stability mechanism, inorganic salt clay stabilizers, surfactant clay stabilizers and polymer clay stabilizers were studied, aiming to optimize the clay stabilizer for acidizing. Firstly, PDMDAAC and CPAM were successfully prepared and characterized. Then, the performance of seven clay stabilizers, including NH4Cl, KCl, dodecyl trimethylammonium chloride (DTMA), cetyltrimethylammonium chloride (CTMA), amide Gemini quaternary ammonium salt (GSA), PDMDAAC and CPAM, were compared under different conditions. The results show that the 2% salt clay stabilizer can reach 90% of the anti-swelling rate. While 1% surfactant and polymer can reach 70% and 80% of the anti-swelling rate respectively. In addition, the salt clay stabilizer has great high-temperature resistance and the polymer clay stabilizer has good scour resistance. In contrast, the surfactant clay stabilizer has poor effect in acid environment owing to critical micelle concentration. The mechanism research shows that the electrostatic interaction of the cations ionized by inorganic salt and the negative ions in the clay stabilizes clay. Besides ionizing cations, surfactant clay stabilizer and polymer clay stabilizer prevent the external fluid from entering clay interlayer through the aggregation of hydrophobic groups and the formation of polymer film respectively.