Extenders allow the production of a greater volume of slurry from the powdered cement. This feature can result in reduced cost and, where the extenders are lightweight (or they allow additional
water to be used), lower density. The advantage of reduced cost is obvious. Reduced density is important where weak formations are to be cemented. Such weak formations could part and
allow loss of the slurry during the cementing operation. A variety of extenders are available to provide for different requirements of lower density, lower cost and other performance parameters.