Low fluid loss drilling fluid compositions comprising diblock copolymers
US9394472B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 27, 2014 |
| Grant date | Jul 19, 2016 |
| Priority date | — |
| Expiry date | Aug 20, 2034 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC09K2208/00
- WIPO fieldBasic materials chemistry
- WIPO sectorChemistry
Abstract
The invention relates to a selectively hydrogenated isoprene-styrene diblock copolymer having a polystyrene content of at least 40 wt. %, which when added to an oil-based mud composition, substantially reduces fluid loss. The polystyrene in the diblock has a true molecular weight greater than 60 kg/mole and the total apparent molecular weight of the diblock copolymer is at least 160 kg/mole. The drilling mud that contains about 0.5 pounds per barrel to about 10 pounds per barrel of a selectively hydrogenated isoprene-styrene diblock copolymer and a weighting agent, resulting in a drilling fluid composition exhibiting good suspension of the weighting agent and improved fluid loss performance.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.