Measuring and modeling hydration kinetics of well cements under elevated temperature and pressure using chemical shrinkage test method

Abstract

Well cements hydrate under challenging conditions of elevated temperature and pressure. A standard and readily accessible experimental method to follow the hydration kinetics of well cements under these conditions is lacking. In this study, we present a new method to measure the chemical shrinkage of cements, using an ultrasonic cement analyzer coupled with an external pump — two common equipment in well cements research laboratories. The method measures chemical shrinkage by following the flux of water into the sample to maintain constant pressure. Various experimental parameters such as leakage and sample geometry are carefully examined. Chemical shrinkage results on Class G and Class H cements are in good agreement with various sources, including reported chemical shrinkage, reported activation constants, hydration kinetics measured by alternative methods, and phase assemblage measurements on hardened paste. The method offers a promising new technique to help advance our fundamental knowledge on the hydration of well cements.