|Title||Nano-chemo-mechanical signature of conventional oil-well cement systems: Effects of elevated temperature and curing time|
|Publication Type||Journal Article|
|Year of Publication||2015|
|Authors||Krakowiak KJ, Thomas JJ, Musso S, James S, Akono A-T, Ulm F-J|
|Journal||Cement and Concrete Research|
|Pagination||103 - 121|
With ever more challenging (T,p) environments for cementing applications in oil and gas wells, there is a need to identify the fundamental mechanisms of fracture resistant oil well cements. We report results from a multi-technique investigation of behavior and properties of API class G cement and silica-enriched cement systems subjected to hydrothermal curing from 30 °C to 200 °C; including electron probe microanalysis, X-ray diffraction, thermogravimetry analysis, electron microscopy, neutron scattering (SANS), and fracture scratch testing. The results provide a new insight into the link between system chemistry, micro-texture and micro-fracture toughness. We suggest that the strong correlation found between chemically modulated specific surface and fracture resistance can explain the drop in fracture properties of neat oil-well cements at elevated temperatures; the fracture property enhancement in silica-rich cement systems, between 110° and 175 °C; and the drop in fracture properties of such systems through prolonged curing over 1 year at 200 °C.
|Short Title||Cement and Concrete Research|