Process for controlling iron
US5972849A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 6, 1995 |
| Grant date | Oct 26, 1999 |
| Priority date | — |
| Expiry date | Nov 6, 2015 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC09K8/74
- WIPO fieldBasic materials chemistry
- WIPO sectorChemistry
Abstract
In the presence of certain crude oils, when ferric iron exists in very acidic fluid, it practically instantaneously forms precipitates known as sludges which lead to irreversible damage. Iron control compositions and acid fluids containing such iron control compositions are disclosed. For acid fluids containing up to 15% acid, the iron control composition includes a reducing agent selected from a substituted and unsubstituted thiourea compounds, and a reduction catalyst including a copper (cuprous or cupric) compound. When the acid fluid contains more than 15% acid, for example from 15 to 28% acid, the reducing agent is again selected from substituted or unsubstituted thiourea compounds, and the reduction catalyst is a combination of a copper (cuprous or cupric) compound and iodine (iodine or iodide ions). The invention also includes a process for treatment of oil, water, gas, geothermal or analogous wells using an acid fluid containing an iron control composition according to the present invention, and an industrial cleaning process using a cleaning fluid including an acid fluid containing an iron control agent according to the present invention.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.