Fluid having recyclable viscosity
US7290615B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Sep 17, 2004 |
| Grant date | Nov 6, 2007 |
| Priority date | — |
| Expiry date | Feb 3, 2026 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC09K2208/30
- WIPO fieldBasic materials chemistry
- WIPO sectorChemistry
Abstract
Compositions are given that have high viscosities at one pH range and low viscosities at another pH range. Methods are given for using such compositions in oilfield treatments. In particular CT wellbore cleanout compositions and methods are given in which a viscous fluid is injected into a wellbore; the fluid entrains particles and carries them to the surface; the viscosity of the fluid is reduced by reducing or increasing the pH; the particles settle from the fluid; the viscosity of the fluid is increased by increasing or reducing the pH; and the fluid is re-injected into the wellbore. Suitable surfactants are anionic surfactants, or mixtures of surfactants containing anionic surfactants, that aggregate into three-dimensional structures that substantially increase the viscosity at high pH but not at low pH. Other suitable surfactants are cationic surfactants with co-surfactants that aggregate below a certain pH but not above.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.