BigPatents India

The present invention relates to a non-foamed high performance lightweight cement slurry compositions having low fluid loss, low rheology, nil free water, high stability, gas tight property and enhanced compressive strengths and lower permeability upon setting which makes it especially suitable for application in cementing against oi/gas bearing producing zones in varieties of well bore conditions comprising of a coarse hydralic cement, fume silica, lighweight aggregate, dispersant, set cement retarder, optionally fluid loss control additive and defoaming agent, water in a quantity sufficient to provide a slurry of density ranging from 1.00 to 1.50g/cm cube and the invention also relates to a proces for the preparation of said cement slurry composition by adding dispersant, cement set retarder, optionally fluid loss additive and defoaming agent to sufficient quantity of water, mixing, adding to ita a blend of fume silica and coarse hydraulic cement followed by lightweight aggregate and finally mixing in a Warring blender.