f Investigation of the Effect of Additives on Strength Properties of Cement

Cementing is one of the most essential operations for drilling and well completion techniques. Cement is used in drilling operations to support and protect casing, to prevent flow through annular space outside the casing, to stop flow into vugular or fractured formation and to isolate or close an abandoned portion of a well. In addition, it is also a desired property for cement to develop early high compressive strength to reduce drilling cost. Therefore, different cement additives are used to provide desired needs. In this study, 1, 7, and 28-day of compressive strength variation of Class G cement having commercial additives (viscosity controller and water loss reducer) with different concentration at ambient conditions have been investigated experimentally. Amount of used additives was within the limits as specified by producer. It has been observed that cement samples having water loss additive have resulted in lower compressive strengths in short terms than those of samples having viscosity control additive. Otherwise, it has also been determined that the viscosity control additive have yielded a property that tends to increase the compressive strengths in long terms. First time in this study, it has been observed that one-day cement samples prepared with high amount of water loss additive (1% by weight of cement) have been deformed plastically under compressive loads indicating that have no ability to carry loads or to develop compressive strength.