Method for explosively expanding a pillar for forming an in situ oil shale retort
US4290649A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Nov 7, 1979 |
| Grant date | Sep 22, 1981 |
| Priority date | — |
| Expiry date | Nov 7, 1999 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE21C41/24
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
An in situ oil shale retort is formed in a subterranean formation containing oil shale, a horizontally extending void is excavated within the boundaries of the retort site leaving a zone of unfragmented formation above and/or below such a void, at least one pillar of unfragmented formation is left within the side boundaries of such a void for providing temporary support for overburden above the void, such a pillar is explosively expanded so that a principal portion of the pillar fragments travel to the side boundaries of the void and such a zone of unfragmented formation is explosively expanded toward the void. Accumulation of sufficient pillar fragments adjacent the side boundaries of the retort can substantially offset a tendency for fragments of the expanded zone of formation to form a mound thereby forming a fragmented permeable mass of formation particles within the retort with a reasonably flat upper surface. Such a fragmented permeable mass is retorted in situ to produce shale oil.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.