Additive for increasing the density of a fluid for casing annulus pressure
US7589049B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Sep 26, 2005 |
| Grant date | Sep 15, 2009 |
| Priority date | — |
| Expiry date | Sep 26, 2025 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC09K2208/18
- WIPO fieldBasic materials chemistry
- WIPO sectorChemistry
Abstract
A method of controlling the pressure of a casing annulus in a subterranean well that includes injecting into the casing annulus a composition including a base fluid and a polymer coated colloidal solid material. The polymer coated colloidal solid material includes: a solid particle having an weight average particle diameter (d50) of less than two microns, and a polymeric dispersing agent coated onto the surface of the solid particle during the cominution (i.e. grinding) process utilized to make the colloidal particles. The polymeric dispersing agent may be a water soluble polymer having a molecular weight of at least 2000 Daltons. The solid particulate material may be selected from materials having of specific gravity of at least 2.68 and preferably the solid particulate material may be selected from barium sulfate (barite), calcium carbonate, dolomite, ilmenite, hematite, olivine, siderite, strontium sulfate, combinations and mixtures of these and other similar solids that should be apparent to one of skill in the art.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.