Impregnation of novel additives in cement for preventing fluid migration through the cement sheath in oil well

Abstract

At elevated temperature and pressure, oil well cements shrink after setting resulting in reduction of volume. The shrinkage in set cement result into generation of micro annuli in cement sheath, resulting in upward migration of fluid. Thus the present study aims at developing a cost effective cement system which should demonstrate expansion properties at elevated temperature and pressure. To explore this experiments were performed to assess the shrinkage of the cement slurry with impregnation of various expansion additives. Further, the investigations were explored in various downhole conditions of oil well. The experimental study confirms the general theory about shrinkage, when a particle of cement reacts with water, the volume of the hydration product is less than the initial volume of cement plus water. Micro bond demonstrated the percentage shrinkage about 4% under permeable and impermeable conditions. The shrinkage got further reduced by 1.5% under high pressure temperature testing conditions.