Low fluid loss salt saturated cement slurries, additives and methods

摘要

Low fluid loss salt-saturated cement slurries for oil and gas well cementing operations, comprise hydraulic cement; salt-saturated water present in an amount sufficient to form a pumpable slurry; and a fluid loss-reducing complex comprised of the reaction product of polyethyleneimine having a molecular weight above about 50,000 and one or more sulfonated organic compounds selected from lignosulfonic acid salts having Na, Ca or NH4 as the associated cation and naphthalene sulfonic acid condensed with formaldehyde, having a molecular weight above about 5,000.