Modified cement composition, preparation and application thereof

The modified cement composition of claim wherein the gas migration controlling agent comprises at least one of (i) a composition including at least about 90% SiO2, from about 0.5% to about 2.0% Al2O3, from about 0.2% to about 1.5% Fe2O3, from about 0.1% to about 0.5% CaO, from about 0.1% to about 1.5% Na2O, from about 0.5% to about 2.0% K2O, from about 0.5% to about 2.0% MgO, from about 0.1% to about 0.4% SO3, and from about 0.5% to about 2.5% C and (ii) a composition including at least latex particles.

A modified cement composition comprising cement, hydrophobic nano-silica, and at least one additive and water to make a cement slurry having a 24-hour compressive strength of about 4450 psi, wherein the at least one additive comprises at least one of light weight additive, an anti-foaming agent, a retardant, an accelerator, a dispersant, a fluid loss controlling agent, a surfactant, and a gas migration controlling agent.

A modified cement composition comprising cement with a particle size of from about 10 μm to about 50 μm, hydrophobic nano-silica with a surface area of from about 110 m2/g to about 260 m2/g, at least one additive with a particle size of from about 51 μm to about 370 μm, and a sufficient amount of water to make a cement slurry, wherein the at least one additive comprises at least one of light weight additive, an anti-foaming agent, a retardant, an accelerator, a dispersant, a fluid loss controlling agent, a surfactant, and a gas migration controlling agent.