Gas leakage through a cemented wellbore annuli is a major problem in many oil wells in the world, and specifically in the United States. Enormous amounts of money are spent on squeeze cementing these affected wells often without effecting a permanent solution. This problem is not only expensive to control, but also a menace to the environment. Gas leakage occurs as a result of bad cement-formation bonding caused by incompatible contraction-expansion mechanism during cement setting.

This work proposes the use of new cementing additives which can reduce the effect of the expansion-contraction mechanism during the cement slurry setting. These additives fill contraction induced voids within the cement structure and between the pipe and cement, which leads to an impermeable cement, thus eliminating the existence of micro-fractures and micro-annulus. These materials are economic to use and are readily available. It is proposed that the cement bond index should be estimated in the laboratory using Ultra-Sonic test prior to the cement job.

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