Rietveld quantitative phase analysis of Oil Well Cement: in situ hydration study at 150 bars and 150ºC

Raw data for: Rietveld Quantitative Phase Analysis of Oil Well Cement: In Situ Hydration Study at 150 Bars and 150 °C;

doi: https://doi.org/10.3390/ma12121897

Oil well cements are multimineral materials that hydrate under high pressure and temperature. Its overall reactivity at early ages is studied by a number of techniques including the consistometer. However, for a proper understanding of the performances of these cements in the field, the reactivity of every component, at the field conditions, must be analysed. So far, in situ high energy synchrotron powder diffraction studies of hydrating oil well cement pastes have been carried out but the quality of the data was not appropriated for Rietveld quantitative phase analyses. Therefore, the phase reactivities were followed by the inspection of the evolution of non-overlapped diffraction peaks. Very recently, we have developed a new cell specially designed to rotate under high pressure and temperature. Here, this spinning capillary cell is used to in situ study the hydration of a commercial oil well cement paste at 150 bars and 150 ºC. The powder diffraction data have been analysed by the Rietveld method to quantitatively determine the reactivities of each component phase. The reaction degree of alite was 90% after 7 hours and that of belite was 42% at 14 hours. These analyses are accurate as the in situ measured crystalline portlandite content at the end of the experiment, 12.9 wt%, compares relatively well with the value determined ex situ by thermal analysis, 14.0 wt%. The crystalline calcium silicates forming at 150 bars and 150 ºC are also discussed.