Sulfate scale dissolution
US5200117A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 16, 1992 |
| Grant date | Apr 6, 1993 |
| Priority date | — |
| Expiry date | Jan 16, 2012 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC02F2101/006
- WIPO fieldEnvironmental technology
- WIPO sectorChemistry
Abstract
Alkaline earth metal scales, especially barium sulfate scale deposits are removed from oilfield pipe and other tubular goods with a scale-removing composition comprising an aqueous alkaline solution having a pH of about 8 to about 14, preferably about 11 to 13, of a polyaminopolycarboxylic acid, preferably EDTA or DTPA and a catalyst or synergist comprising a monocarboxylic acid, preferably a substituted acetic acid such as mercaptoacetic, hydroxyacetic acid or aminoacetic acid or an aromatic acid such as salicylic acid. When the scale-removing solution is contacted with a surface containing a scale deposit, substantially more scale is dissolved at a faster rate than is possible without the synergist.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.