Sep. 11, 2014  17  US 2014/0256604 Al  wherein the cationic viscoelastic surfactant is in at least a  sufficient critical concentration in the treatment fluid to  impart viscoelastic behavior to the treatment fluid after  at least some of the strong acid spends in the formation.  2.  (  canceled)  3.  The method according to claim  1,  wherein the strong  acid comprises hydrochloric acid.  4.  The method according to claim  1,  wherein the cationic  viscoelastic surfactant is or comprises a viscoelastic surfac› tant having a nitrogen atom with short chain alkyl groups.  5.  The method according to claim  1,  wherein the cationic  viscoelastic surfactant is or comprises a quaternary ammo› nium fatty amine.  6.  The method according to claim  5,  wherein the quater› nary ammonium fatty amine is or comprises bis(hydroxyeth› yl)methyloleylammonium chloride.  7.  The method according to claim  5,  wherein the design  temperature of the zone is higher than 93°  C. (200°  F.).  8.  The method according to claim  1,  wherein the design  temperature of the zone is higher than 93°  C. (200°  F.).  9.  The method according to claim  1,  wherein the non› cationic corrosion inhibitor is or comprises the anionic  organic component.  10.  The method according to claim  1,  wherein the non› cationic corrosion inhibitor is or comprises methyl ester sul› fonate.  11.  The method according to claim  9,  wherein the treat› ment fluid additionally comprises: a corrosion inhibitor inten› sifier.  12.  The method according to claim  1,  wherein the treat› ment fluid additionally comprises: a corrosion inhibitor inten› sifier.  13.  The method according to claim  12,  wherein the corro› sion inhibitor intensifier is or comprises the anionic organic  component.  14.  The method according to claim  12,  wherein the corro› sion inhibitor intensifier is or comprises triphenylphosphine.  15.  The method according to claim  1,  wherein the design  temperature of the zone is up to 121 °  C. (250°  F.).  16.  The method according to claim  1,  further comprising  the step of: flowing back fluid from the zone.  17.-27.  (canceled)  *  *  *  *  * 