Iterated foam process and composition for well treatment
US5591701A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Sep 23, 1994 |
| Grant date | Jan 7, 1997 |
| Priority date | — |
| Expiry date | Sep 23, 2014 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S516/05
- WIPO fieldBasic materials chemistry
- WIPO sectorChemistry
Abstract
In the removal of particulates from a wellbore, such as in air drilling for hydrocarbon recovery, a mixture of an amphoteric foaming agent and, typically, an anionic surfactant is employed. An aqueous solution thereof having a pH of at least 9.5 is used to generate a foam for removing the particulates; then the foam is collapsed by the introduction of acid to reduce the pH below about 4, the particles are removed mechanically, the pH is restored to greater than 9.5, and the foaming solution is returned to the wellbore. The solution may be used several times; partial losses of foaming agent in the process may be easily replenished with each cycle. Cationic surfactants may be used instead of anionic, with foaming and foam collapse being controlled at opposite pH's. Savings are realized in water, drilling chemicals, and settling pits and the like for removing particulates from the foam.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.