Compositions and methods for controlling wellsite fluid and gas flow

Abstract

Magnesium oxysulfate cement compositions and methods for controlling and preventing fluid and gas flow through a wellbore are described. The compositions and methods may be implemented to provide a barrier to fluid and gas flow between casings or in other operations such as squeeze operations. Magnesium oxysulfate cement compositions may include an admixture of magnesium oxide, magnesium sulfate trihydrate and water. When admixed with water, the compositions rapidly transition from a flowable state to a solid state with formation of little or no gel strength before the transition and further have a near-linear relationship between the time required for the transition to occur and the composition temperature at which the transition occurs enabling the user to determine the time within which the transition will occur. Additives, such as accelerators and inhibitors can be added to modify the time in which the compositions make the transition from flowable state to solid state. Other agents can be added to modify the specific gravity and viscosity of the compositions.