Method for restoring contaminants to base levels in previously leached formations
US4418961A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 27, 1982 |
| Grant date | Dec 6, 1983 |
| Priority date | — |
| Expiry date | May 27, 2002 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE21B43/28
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
The present invention relates to a method for restoring to environmentally acceptable levels the soluble contaminants in a subterranean formation that has been subjected to oxidative leaching. The contaminants are defined as those ionic species that when subjected to calcium ions form precipitates which are insoluble in the formation fluids. In accordance with the present invention, soluble calcium values are introduced into the formation. The level of contaminants is monitored and when such reaches the desired level, the introduction of soluble calcium values is stopped. The introduction of calcium values may be achieved in several ways one of which is to inject into the formation an aqueous solution containing therein solubilized calcium values. Another method of introducing calcium values into a formation, is to inject into the formation an aqueous solution containing carbon dioxide to solubilize calcium values, such as calcium carbonates, found in the formation.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.