Acrylamide/Acrylic Acid Copolymers for Cement Fluid Loss Control

Abstract

Acrylamide/acrylic acid copolymers are effective fluid loss control additives in a wide range of oil well cements. Unlike HEC based fluid loss additives, these copolymers can be used with calcium chloride accelerator without significantly influencing fluid loss control. Another advantage of the copolymers is that the amount of fluid loss for a given concentration of polymer remains relatively constant over a wide range of temperatures. The use of acrylamide/acrylic acid copolymers has generally been restricted to wells below 60°C BHCT. Above that temperature chemical changes in the copolymer often lead to retardation of the cement. This paper presents data related to the use of acrylamide/acrylic acid copolymers as fluid loss control agents in oil well cementing. A comparison of these polymers with HEC based fluid loss control additives is made. In addition, data related to the cause of acrylamide/acrylic acid copolymer retarding effects is presented.

Experimental Investigation on The Effect of PolyVinyl Alcohol on Cement Fluid Loss in Oil Wells

“…Today this type of dispersant most commonly used to reduce viscosity of cement slurry and it makes effect on cement fluid loss. Another fluid loss control additive used in oil/gas wells is called acrylamide/acrylic acid copolymers [8]. In their study a relationship between temperature and fluid loss is concluded.…”

New Fluid-Loss Additives for Oilfield Cementing

“…Fluid loss additives based upon copolymers of acrylamide and acrylic acid have been developed, however, for use in the completion of very hot wells (4). At the extreme temperatures encountered in these wells, cement slurries require a fairly high loading of retarder.…”

“…A number of synthetic copolymers have been developed for use as fluid loss additives in recent years (4). Most appear to have some limitations in their application as their use often results in cement slurries which are difficult to mix over-retarded or excessively dispersed.…”