Abstract
The development of new drilling technologies and the increase of severe operation conditions related to deep water applications lead to enhance the performance of drilling fluid and cement formulations. Success of cementing operations depends on slurry placement and then on the material properties under temperature and pressure conditions. A novel cement developed for high temperature wells is proposed. This material issued from civil engineering is composed of classical Portland cement and silica particles. The major problem in these formulations was to manage with the compacity of dry powders by a better choice of the particle size distribution of cement and silica grains. At least two types of silica were used, one was a crushed sand and the other a silica fume. The control of the initial homogeneity of the dry mixture allowed to adjust the rheology of the granular media in water. The slurry fluidity is finally adjusted by an optimum in the concentration of the dispersant additive leading to a minimum in viscosity.
Other additives such as retarders and fluid loss reducer were selected according to the temperature range of use. Properties of the setting material were evaluated by compressive tests on crashed core and water permeability measurements. Test results indicated good relation between mechanical properties and initial compacity of the cement systems.
