Encapsulated oil absorbent polymers as lost circulation additives for oil based drilling fluids
US4704213A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 28, 1985 |
| Grant date | Nov 3, 1987 |
| Priority date | — |
| Expiry date | May 28, 2005 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/2989
- WIPO fieldBasic materials chemistry
- WIPO sectorChemistry
Abstract
The disclosed invention is a novel drilling fluid additive for use in reducing lost circulation in wellbores and a method for employing the invention additive for reducing such lost circulation. The invention additive is a highly oil absorbent polymer encapsulated by a reaction-preventive protective casing to prevent the polymer from expanding by absorbing oil until it is desired to breach the casing. The reaction-preventive protective casing may be a film which will dissolve after a desired time of residence in the borehole or a film or clay which can be ruptured in the formation, releasing the oil absorbent polymer to expand by absorbing oil. The substantially expanded polymer will seal off their zones and fissures, reducing lost circulation.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.