Investigation on rheological properties and thickening mechanism of a novel thickener based on hydrophobically associating water-soluble polymer during the acid rock reaction

摘要

A novel betaine-type hydmphobically associating polyacrylamides (CPAM) consisting of acrylamide (AM), 1-carboxy-N, N'-dimethyl N (3-methyl-acrylamidopropyl) ethanaminium (CBMAA-1), Methacrylatoethyl trimethyl ammonium chloride (DMC) and N, N'-dimethyl octadecyl allyl ammonium chloride (DOAC) was synthesized, which was characterized by FT-IR and 1 H NMR spectra. Rheological properties of CPAM acid solutions were studied via six-speed rotational viscometer and HAAK MARSIII Rheometer. Moreover, the thickening mechanism of CPAM acid solutions during the acid rock reaction was investigated by simulating the acid rock reaction process. Results showed that CPAM acid solutions demonstrated good thickening ability from low apparent viscosity to high apparent viscosity during the acid rock reaction. Meanwhile, CPAM spent acid solutions showed good shear resistance, viscoelasticity and high temperature resistance, showing great potential as a self-diverting acid solution for carbonate formation. Besides, it was found that the main factor of affecting the thickening of the CPAM acid solutions was the concentration of CaCl2.