an acid solution of a water soluble oxyalkylated acrylamido alkanesulfonic acid polymer wherein the said solution is maintained in contact with the formation for a time sufficient to chemically react with the formation so as to increase substantially the flow capabilities of the formation and to release carbon dioxide concomitantly whereby a beneficial effect due to the mutual miscibility of carbon dioxide in the fluid phase is realized as a reduction in viscosity and retentive capillary forces while another beneficial effect is realized in the form of increased formation energy due to the pressure generated by the released carbon dioxide the average molecular weight of the oxyalkylated acrylamido alkanesulfonic acid polymers and copolymers utilized in the method of this invention generally will be from about 1 000 to about 1 000 000 or more and preferably will be from about 1 000 to about 400 000 highly advantageous results are realized with the method of this invention when the water soluble oxyalkylated acrylamido alkanesulfonic acid polymer employed comprises recurring units of the formula str1 wherein r r a r b and r c are independently selected from the grou 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 3 h 6 o n c 2 h 4 o m m wheerein n is an integer of from 0 to about 5 m is an integer of from 3 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 3 h 6 o r c 2 h.