A new lightweight concrete is under development which exhibits superior mechanical, thermal and acoustic properties and weighs less than water. It is planned to use this innovative material to construct precast concrete panels for building envelopes. The material derives its special properties from a combination of novel admixtures and mix design formulations that produce a unique pore structure which is quite different from that achieved by traditional foaming agents. The matrix of isolated voids will drastically increase the thermal resistivity and sound absorptive properties of the concrete and increase its ductility. The inclusion of large quantities of air also reduces the amounts of natural resources required for building construction. These factors constitute a major step towards green building construction.
OIL WELL CEMENTING
Cross Section of an Oil Well
In oil wells, a cement sheath serves to isolate different geologic formations and prevent the migration of hydrocarbons or water from one layer to another. Oil well cements with depths up to 30,000 ft and more are subject to wide ranges of pressure and temperature. These pose considerable challenges to the industry. We have cooperated with Halliburton Energy Services for over 10 years in an attempt to solve some of the pressing problems.
Pressure Test Cell Development
One of the most difficult tasks is the determination of material properties of cement slurries hydrated under in situ conditions, i.e. high pressure and high temperature. We are currently developing a unique pressure test cell which permits the hydration of a cement slurry under in situ conditions down hole and allows us to determine various mechanical properties without exposing the specimen to ambient conditions.
Mathematical Modeling of Cement Hydration and Shrinkage
Shrinkage is an important property that affects the effectiveness of the cement sheath’s zonal isolation. In order to predict shrinkage of cement under down-hold conditions, a multi-scale, micromechanics-based constitutive model has been developed. However, its final calibration and validation is dependent on experimental data to be obtained with the pressure test cell under development. The model is derived on the basis of thermodynamics and cement hydration kinetics, combined with continuum mechanics and poroelasticity.
For further information contact Christian Meyer at +1.212.854.3428.