Use of recycled combustion gas during termination of an in-situ combustion oil recovery method
US4415031A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Mar 12, 1982 |
| Grant date | Nov 15, 1983 |
| Priority date | — |
| Expiry date | Mar 12, 2002 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE21B43/40
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
A method for recovering viscous oil from a subterranean, viscous oil-containing formation by initiating an in-situ combustion operation in the formation using a mixture of oxygen and an inert gas having a low oxygen concentration, preferably about 21 vol. %. After a predetermined period of time, the oxygen concentration is increased to a predetermined higher level, preferably within the range of 95 to 99.5 vol. %. Once the oxygen concentration has reached the desired value, water may be simultaneously injected continuously or intermittently. After a predetermined period of time, produced combustion gas enriched in carbon dioxide separated from the produced oil is compressed and recycled as a diluent for the injected oxygen in place of the inert gas. Thereafter, wet in-situ combustion operation is continued and the oxygen concentration of the injected mixture of oxygen and combustion gas diluent is maintained at a predetermined value so that the concentration of oxygen in the produced combustion gas is maintained at a predetermined value low enough to avoid the danger of an explosion or burning of the production well. After a predetermined period of time, injection of oxygen is term…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.