Cementing oil and gas wells using converted drilling fluid
US4883125A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 11, 1987 |
| Grant date | Nov 28, 1989 |
| Priority date | — |
| Expiry date | Dec 11, 2007 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC09K8/467
- WIPO fieldBasic materials chemistry
- WIPO sectorChemistry
Abstract
Wellbores are cemented with a cement composition formed from drilling fluid occupying the wellbore by circulating a quantity of drilling fluid mixed with a cement material and a dispersant such as a sulfonated styrene copolymer with or without an organic acid into the wellbore to displace the drilling fluid and to continuously convert the drilling fluid into the cement composition. The cement composition may be recirculated through the space in the wellbore to completely evacuate any drilling fluid not converted to cement so as to minimize any faults in the cement composition occupying the wellbore. A preflush composition containing the dispersant and being rheologoically compatible with both the drilling fluid and the drilling fluid converted to cement slurry may be used as a displacement fluid.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.