Encapsulated lime as a lost circulation additive for aqueous drilling fluids
US4614599A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Apr 1, 1985 |
| Grant date | Sep 30, 1986 |
| Priority date | — |
| Expiry date | Apr 1, 2005 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S507/902
- 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 lime encapsulated by a reaction-preventive protective casing to prevent the lime from reacting with clays in the borehole 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 waxy substance which will dissolve or melt at a desired temperature in the borehole, releasing the lime to react with clays in the formation or in the borehole to form a cement-like mass.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.