Modelling of the elastic parameters development of an oilwell cement paste at a very early age under downhole conditions

Abstract

The characterisation and modelling of the mechanical behaviour of an oilwell cement paste at a very early age (≤24h) under high pressure and elevated temperature are studied. A multiscale homogenization approach is adopted. For this purpose, the evolution of the volume fractions of the different phases of the cement was determined by means of a kinetics model for the four main hydration reactions of a class G oilwell cement. Calorimetric experiments were performed in order to be compared with the results of the used kinetics model, on the one hand, and to study pressure and temperature effect on the hydration kinetics, on the other hand. A homogenization model is presented in order to predict the bulk and shear moduli evolutions. The model-based results are in agreement with dynamic moduli measurements data from ultrasonic propagation.