Claims
- 1. A method of treating a subterranean limestone or dolomitic formation or a sandstone formation having a substantial carbonate content associated with a well completed in said limestone or dolomitic formation or said sandstone formation having a substantial carbonate content comprising displacing into said formation through said well an effective amount of an acidic aqueous solution comprising from about 5 to about 36% by weight phosphoric acid, from about 0.6 to about 5 weight % of a highly polar surface active agent which is a citric acid-monoethanolamine elimination reaction product characterized by a visible absorption spectrum which displays an increasing extinction coefficient from the red to the near U.V. with some structure, an absorption maximum at 475 nm, a plateau from 460 nm to 465 nm, an absorption maximum at 450 nm, and extinction coefficients as follows:
- .epsilon..sub.475 =0.325 l/gm.cm
- .epsilon..sub.462 =0.379 l/gm.cm
- .epsilon..sub.450 =0.509 l/gm.cm,
- an effective amount of a ferrous metal corrosion inhibitor, and an amount of a phosphate crystal modifying agent sufficient to control crystal growth, minimize crystal agglomeration and minimize crystal adhesion to the formation, said phosphate crystal modifying agent being selected from the group consisting of polyacrylate polymers and blends of such polymers with a phosphonic acid or a phosphonate.
- 2. A method according to claim 1 wherein the acidic aqueous solution is displaced into said formation under a pressure greater than the formation pressure but less than that causing fracture of the formation.
- 3. A method according to claim 2 wherein in the acidic aqueous solution the phosphoric acid is present in an amount of from about 15 to about 22 weight % and the citric acid-monoethanolamine elimination reaction product is present in an amount of from about 1 to 1.5 weight %.
- 4. A method according to claim 2 wherein in the acidic aqueous solution the phosphoric acid is present in an amount of from about 5 to about 22 weight % and the citric acid-monoethanolamine elimination reaction product is present in an amount of from about 1 to about 2.5 weight %.
- 5. A method according to claim 2 wherein in the acidic aqueous solution the phosphoric acid is present in an amount of from about 10 to about 28 weight % and the citric acid-monoethanolamine elimination reaction product is present in an amount of from about 1 to about 5 weight %.
- 6. A method according to claims 3, 4, or 5 wherein in the acidic aqueous solution there is additionally included an amount of a nonionic or anionic surfactant sufficient to impart improved surface active properties and hydroxyacetic acid.
- 7. A method according to claims 3, 4 or 5 wherein in the acidic aqueous solution the ferrous metal corrosion inhibitor is a dialkyl thiourea, and there is additionally included an amount of a nonionic or anionic surfactant sufficient to impart improved surface active properties and hydroxyacetic acid.
- 8. A method according to claims 3, 4 or 5 wherein in the acidic aqueous solution the ferrous metal corrosion inhibitor is a dialkyl thiourea, and solution there is additionally included an amount of an nonionic or anionic surfactant sufficient to impart improved surface active properties, hydroxyacetic acid and an amount of an acid stable antifoaming agent sufficient to prevent foaming.
- 9. A method according to claim 1 wherein the acidic aqueous solution is displaced into said formation under a pressure sufficient to fracture the formation.
- 10. A method according to claim 9 wherein in the acidic aqueous solution the phosphoric acid is present in an amount of from about 15 to about 22 weight % and the citric acid-monoethanolamine elimination reaction product is present in an amount of from about 1 to about 1.5 weight %.
- 11. A method according to claim 9 wherein in the acidic aqueous solution the phosphoric acid is present in an amount of from about 5 to about 22 weight % and the citric acid-monoethanolamine elimination reaction product is present in an amount of from about 1 to about 2.5 weight %.
- 12. A method according to claim 9 wherein in the acidic aqueous solution the phosphoric acid is present in an amount of from about 10 to about 28 weight % and the citric acid-monoethanolamine elimination reaction product is present in an amount of from about 1 to about 5 weight %.
- 13. A method according to claims 10, 11 or 12 wherein in the acidic aqueous solution there is additionally included an amount of a nonionic or anionic surfactant sufficient to impart improved surface active properties and hydroxyacetic acid.
- 14. A method according to claims 10, 11 or 12 wherein in the acidic aqueous solution the ferrous metal corrosion inhibitor is a dialkyl thiourea, and there is additionally included an amount of a nonionic or anionic surfactant sufficient to impart improved surface active properties and hydroxyacetic acid.
- 15. A method according to claims 10, 11 or 12 wherein in the acidic aqueous solution the ferrous metal corrosion inhibitor is a dialkyl thiourea, and there is additionally included an amount of a nonionic or anionic surfactant sufficient to impart improved surface active properties, hydroxyacetic acid and an amount of an acid stable antifoaming agent sufficient to prevent foaming.
Priority Claims (1)
Number |
Date |
Country |
Kind |
325951 |
Apr 1979 |
CAX |
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Parent Case Info
This application is a division, of application Ser. No. 97,151, filed 11/26/79, now abandoned.
US Referenced Citations (8)
Divisions (1)
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Number |
Date |
Country |
Parent |
97151 |
Nov 1979 |
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