Secondary recovery process

Claim 1

A process for recovering hydrocarbons from a hydrocarbon-bearing formation containing acid-soluble components having at least one injection well and at least one production well penetrating the said formation and in fluid communication, which comprises displacing through the formation a composition comprising an acidic aqueous polymer solution and recovering hydrocarbons through the production well, the said acidic aqueous polymer solution comprising about 0.1 to about 10 percent by weight based on the total solution weight of an oxyalkylated acrylamido alkanesulfonic acid polymer dissolved in an aqueous solution of a mineral acid selected from the group consisting of hydrochloric acid and sulfuric acid, and wherein the said oxyalkylated acrylamido alkanesulfonic acid polymer comprises recurring units of the formula: ##STR6## wherein R, R a , R b and R c are independently selected from the group consisting of hydrogen and alkyl having from 1 to 5 inclusive carbon atoms, R d is selected from the group consisting of hydrogen and --(C 2 H 4 O) m M, wherein m is an integer of from 1 to about 20 and M is selected from the group consisting of hydrogen, sodium, potassium and ammonium and R e is selected from the group consisting of hydrogen and --(C 2 H 4 O) s M wherein s is an integer of from 1 to about 20 and with the proviso that when R d is hydrogen, then R e is --(C 2 H 4 O) s M and when R e is hydrogen, then R d is --(C 2 H 4 O) m M, and wherein the average molecular weight of the polymer ranges from about 1,000 to about 1,000,000.