HYDROLYZED CO-POLYMERS OF N-VINYLAMIDE AND ACRYLAMIDE FOR USE AS WATERLOSS CONTROL ADDITIVES IN DRILLING MUD

摘要

186PUS03889ABSTRACTAqueous, clay-based drilling mud compositions are improved with respectto waterloss control by the addition of a hydrolyzed copolymer of acrylamideand an N-vinylamide. The copolymer, which is effective over a broad range ofmolecular weights, contains at least 5 mol percent of the N-vinylamide monomermoiety of which at least 5 mol percent is hydrolyzed to vinylamide units.Well drilling is improved by circulating through the bore hole a drilling mudcontaining this waterloss control additive.