Inhibition of scale formation from oil well brines utilizing a slow release composition
US5399270A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Aug 6, 1992 |
| Grant date | Mar 21, 1995 |
| Priority date | — |
| Expiry date | Aug 6, 2012 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S507/927
- WIPO fieldBasic materials chemistry
- WIPO sectorChemistry
Abstract
A method for the inhibition of scale deposition on the surfaces of a well coproducing oil and scale forming brines comprising injecting into the well reservoir an acidic aqueous solution at a first pH containing dissolved therein a scale inhibitor, multivalent metal ions, and a heat-sensitive pH-increasing substance containing no more than 10 carbon atoms, which decomposes at elevated temperatures liberating an alkaline compound such that the solution is inherently heated by the higher ambient reservoir temperature to a temperature at which the alkaline compound is liberated from the heat-sensitive substance thus raising the pH of the solution to a point at which a sparingly soluble multivalent metal salt of the scale inhibitor is phase separated from the solution on the porous surfaces of the reservoir rock formation, providing for a slow release of inhibitor into the produced brines when the well is in its production phase.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.