and is expected to go as high as about 10 mole percent with 0 01 to 5 being preferred the molecular weight of the polymers described above may vary over a wide range e g 10 000 30 000 000 the invention however finds its greatest usefulness when the acrylamide copolymers have molecular weights in excess of 1 000 000 the copolymers are prepared by a water in oil emulsion technique such processes have been disclosed in u s pat no 3 284 393 u s pat no re 28 474 and u s pat re no 28 576 herein incorporated by reference the technique comprises preparation of an aqueous phase ranging from about 50 to about 90 by weight of the total emulsion which aqueous phase is comprised of water monomers as described above chelating agents and initiator s if the particular initiator s chosen are water soluble ethylenediamine tetraacetic acid or diethylenetriamine pentaacetic acid and their salts are suitable but not limiting chelating agents the water soluble initiator may be selected from peroxides persulfates bromates and azo type initiators such as 2 2 39 azobis 2 amidinopropane dihydrochloride etc sulfites bisulfites sulfur dioxide and other reducing agents used with oxidizing initiators to form an initiating redox pair may also be used if a reducing agent is used it is added as described below the total amount of monomers will range from about 30 to about 80 by weight based on the total weight of the aqueous phase preparation of an oil phase ranging from about 10 to about 50 by weight of the total emulsion which.