In the Saudi Aramco gas campaign, during the last few years, a high casing-casing annulus phenomenon was observed clearly days or months after rig released. Some of these casing or liner set and cemented across abnormally pressured formations, which contains salt water, gas or combinations of both. These zones were cemented using various cement density ranging from normal to high-density slurries.

The integrity of cement sheath is commonly measured by its ability to provide long term zonal isolation, at the time of completion and for the life of the well. It also has to physically support the casing, withstand pressure cycles, temperature cycles and protect the casing against corrosive fluids. Not all cement applications perform these functions with equal success, and many of those that do, they do not stand up against the forces that exert upon them during time.

This paper is evaluating the expansion and the shrinkage property using class " G" cement in Saudi Arabia, and its effect on the cement matrix. One of the potential problems causing the failure of cement zonal isolation, can be attribute to the over use of chemical expansion additives. The cement bond failure can cause migration of fluid from one zone to another, losses of reservoir fluid, well control issues and poor stimulation operations.

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