Preparation and properties of a new type of temperature-resistant and salt-resistant fluid loss additive ADIM for oil well cement

In order to adapt to the deep high temperature and high salt cementing operation environment, itaconic acid (IA), N,N-dimethylacrylamide (DMAA), 2-acrylamido-2-methylpropanesulfonic acid (AMPS) and heterocyclic alkenes (R) were used as polymerization monomers in this paper. A temperature-resistant and salt-resistant fluid loss additive named ADIM was successfully prepared by free radical aqueous solution polymerization and orthogonal experiment. Thermogravimetric, infrared, nuclear magnetic resonance, and elemental analysis have been utilized for assessing the copolymers' structure and heat resistance. The results showed that the target copolymers with thermal decomposition temperature up to 300 degrees C were successfully prepared. A methodical evaluation was conducted on ADIM's application performance. The results show that when the ADIM content is 5 %, the water loss of fresh water cement slurry is only 44 mL at 220 degrees C, and the water loss of saturated brine cement slurry is only 64 mL at 180 degrees C.In addition to the excellent temperature resistance and salt resistance, the overall performance of ADIM is also good. The mechanism of ADIM was studied by mercury intrusion experiment, scanning electron microscope and TOC test. The results show that ADIM can be adsorbed on the cement particles, effectively reducing the porosity and pore size of the filter cake, thereby reducing the water loss of the cement slurry. ADIM has excellent temperature and salt resistance, which is of great significance for guiding the development of deep oil and gas resources.