Preparation, characterization, and retarding mechanism of high temperature resistant amphoteric ion polymer oil well cement retarderPoly‐AAMDforHTHPapplication

Abstract

The amphoteric ion polymer cement retarder Poly‐AAMD was synthesized by aqueous solution polymerization, the chemical structure, molecular weight, and thermal stability was studied. As a result, the Mn and Mw are 1.3 × 104 and 4.7 × 104 g/mol, respectively, and the initial decomposition temperature is 260°C. Then, the effects of retarder Poly‐AAMD on the application performance of cement slurry, such as settlement stability, thickening time, compressive strength, and rheological properties, were investigated. Especially, the thickening time of cement slurry with 1.2 and 1.5 wt% retarder Poly‐AAMD is 312 and 316 min at 220°C, the compressive strength is larger than 14 MPa at 24 h. Compared to conventional retarders, the temperature resistance has been improved to 220°C. Simultaneously, the initial hydration process of cement slurry was studied by low field NMR based on the T2 value. Moreover, the hydration products of cement slurry with retarder Poly‐AAMD were analyzed depends on the qualitative and quantitative analysis methods, the type and content of hydration products were confirmed by the methods of X‐ray diffraction analysis (XRD), scanning electron microscope (SEM), thermogravimetric analysis (TG), and differential thermal analysis (DTG). Finally, the retarding mechanism of retarder Poly‐AAMD was further studied depends on the results of adsorption amount and Zeta potential.