Method for igniting the top surface of oil shale in an in situ retort
US4027917A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 16, 1975 |
| Grant date | Jun 7, 1977 |
| Priority date | — |
| Expiry date | May 16, 1995 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE21B43/247
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
An in situ oil shale retort is ignited by directing a combustible inlet gas mixture into an ignition zone extending across the top of the in situ retort and igniting the combustible mixture to create a combustion zone in the in situ retort. The ignition zone has a sufficient volume of interconnected open spaces for the movement of inlet gas through the ignition zone with minimal pressure loss, and the in situ retort below the ignition zone has sufficient void volume that inlet gas can be introduced into the ignition zone and moved downwardly through the in situ retort to the bottom. After ignition of the combustible mixture, additional quantities of a combustible mixture are directed into the ignition zone to maintain the combustion zone. Flue gases generated in the combustion zone are moved from the combustion zone toward the bottom of the in situ oil shale retort to establish a retorting zone on the advancing side of the combustion zone. When a self-sustaining combustion zone is established, introduction of combustible mixture can be terminated and an oxygen supplying gas introduced.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.