Process comprising a reversible forming composition
US6286601A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 20, 1999 |
| Grant date | Sep 11, 2001 |
| Priority date | — |
| Expiry date | Dec 20, 2019 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S507/925
- WIPO fieldBasic materials chemistry
- WIPO sectorChemistry
Abstract
A process for circulating an aqueous foam in a wellbore includes the steps of forming a foam from an aqueous composition having a determined pH value, injecting the foam into a well so that it circulates from the surface to the well bottom and then back from the well bottom to the surface, and then changing the pH value of the foam when it returns to the surface. The aqueous composition from which the foam is made includes at least one ionic surfactant whose charge does not practically depend on the pH value and a polyampholytic polymer whose global charge depends on the pH value. This composition gives the foam the property that when the pH of the foam is varied at the surface of the well, the charge of the polyampholytic polymer is modified and the foam becomes destabilized and breaks more readily.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.