Coated and cured proppants
US9290690B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Sep 25, 2012 |
| Grant date | Mar 22, 2016 |
| Priority date | — |
| Expiry date | Oct 6, 2033 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC09K8/536
- WIPO fieldBasic materials chemistry
- WIPO sectorChemistry
Abstract
Solid proppants are coated with a coating that exhibits the handling characteristics of a pre-cured coating while also exhibiting the ability to form particle-to-particle bonds at the elevated temperatures and pressures within a wellbore. The coating includes a substantially homogeneous mixture of (i) at least one isocyanate component having at least 2 isocyanate groups, and (ii) a curing agent comprising a monofunctional alcohol, amine or amide. The coating process can be performed with short cycle times, e.g., less than about 4 minutes, and still produce a dry, free-flowing, coated proppant that exhibits low dust characteristics during pneumatic handling but also proppant consolidation downhole for reduced washout and good conductivity. Such proppants also form good unconfined compressive strength without use of an bond activator, are substantially unaffected in bond formation characteristics under downhole conditions despite prior heat exposure, and are resistant to leaching with hot water.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.