Paper: Cement Topics Spacers And Filtration Control Additives

A test was developed to evaluate cement spacers under conditions simulating mixing in the field. The results have shown that some products did not support barite acceptably well. Dynamic circulation tests demonstrated that spacers did not have the ability to remove mud filter cake as they are widely claimed to do. A test was developed to determine the effect of cement filtration control additives on the filtration from cement slurries through wellformed mud cake. It was found that the additives had little or no effect. Therefore their use in the field for primary cementing has been curtailed in some areas and is under review in others.