Branched viscoelastic surfactant for high-temperature acidizing
A treatment fluid for use in a subterranean formation penetrated by the wellbore of a well includes: (i) water; (ii) a strong acid; and (iii) a branched viscoelastic surfactant having a hydrophobic portion with a total of 16 to 20 carbons; wherein the pH of the treatment fluid is less than 0.5; and wherein the viscosity of the treatment fluid is less than 5 cP at 40 sec−1. A method of treating a zone of a subterranean formation penetrated by a wellbore includes the steps of; (A) forming the treatment; (B) introducing the treatment fluid through the wellbore into the zone; and (C) allowing time for the strong acid in the treatment fluid to spend in the formation.
1. A method of treating a zone of a subterranean formation penetrated by a wellbore, the method comprising the steps of:
(A) forming a treatment fluid comprising:
(i) water;
(ii) strong acid; and
(iii) a branched viscoelastic surfactant having a hydrophobic portion with a total of 16 to 20 carbons;
wherein the treatment fluid has an initial pH of less than 0.5; and
wherein the treatment fluid has a viscosity of less than 5 cP at 40 sec −1 at the initial pH;
(B) introducing the treatment fluid through the wellbore into the zone; and
(C) allowing time for the strong acid in the treatment fluid to spend in the formation.
2. The method according to claim 1 , wherein the strong acid comprises hydrochloric acid.
3. The method according to claim 1 , wherein the treatment fluid does not include hydrogen fluoride.
4. The method according to claim 1 , wherein the branched viscoelastic surfactant comprises a viscoelastic surfactant having a nitrogen atom with short chain alkyl groups.
5. The method according to claim 1 , wherein the branched viscoelastic surfactant comprises a quaternary of a branched fatty acid substituted amidoamine.
6. The method according to claim 5 , wherein the branched viscoelastic surfactant comprises N-Ethyl-N ,N-Dimethyl- [(3-Oxoisooctadecyl)Amino]-1-Propanaminium Ethyl Sulfate.
7. The method according to claim 6 , wherein the zone has a design temperature of higher than 93° C. (200° F.).
8. The method according to claim 1 , wherein the zone has a design temperature of higher than 93° C. (200° F.).
9. The method according to claim 1 , wherein the treatment fluid additionally comprises: a corrosion inhibitor.
10. The method according to claim 9 , wherein the corrosion inhibitor is selected from the group consisting of: an aldehyde, quaternary quinolinium, and any combination thereof.
11. The method according to claim 9 , wherein the treatment fluid additionally comprises: a corrosion inhibitor intensifier.
12. The method according to claim 11 , wherein the corrosion inhibitor intensifier comprises formic acid.
13. The method according to claim 11 , wherein the zone has a design temperature of up to 107° C. (225° F.).
14. The method according to claim 1 , further comprising the step of: flowing back fluid from the zone.