Method of selection of asphaltene precipitant additives and process for subsurface upgrading therewith
US10975291B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Feb 7, 2018 |
| Grant date | Apr 13, 2021 |
| Priority date | — |
| Expiry date | Jun 16, 2038 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE21B43/38
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
In-situ upgrading of heavy hydrocarbons includes injecting into a reservoir solvent, an asphaltene precipitant additive and optionally steam, at a ratio of solvent to heavy hydrocarbon between 0.1:1 and 20:1 under reservoir conditions. The additive has C—H, C—C and/or C—O bonds that thermally crack to generate free radicals in the vapor phase after injection. Formed downhole are a blend containing an upgraded hydrocarbon, and precipitated asphaltenes. The upgraded hydrocarbon is produced such that the precipitated asphaltenes remain in the reservoir. The upgraded hydrocarbon has a greater API gravity, lower asphaltene content, and lower viscosity than the heavy hydrocarbon. The precipitated asphaltenes are present in a higher amount than a similar blend not containing the additive. A method for selecting the additive includes identifying candidate additives having bonds that crack to generate free radicals in the vapor phase at the operating temperature, and calculating percent increase of asphaltenes precipitated for each.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.