Excess - Cement Slurry
Because of the open hole irregularity or enlargement, the volume of slurry required to affect a successful cementing job is often difficult to estimate. In most cases, an excess allowance is made since a shortage of slurry would result in failure of the operation. The cement slurry excess is applied to the required cement volume calculated using gauge hole ID.
Note that the cement slurry excess may not be the same as the open hole excess, though in many cases they are the same.
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