Blasting to a horizontal free face with mixing of fragments
US4326751A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Oct 24, 1980 |
| Grant date | Apr 27, 1982 |
| Priority date | — |
| Expiry date | Oct 24, 2000 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE21B43/248
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
An in situ oil shale retort is formed in a subterranean formation wherein the oil shale retort contains a fragmented permeable mass of formation particles containing oil shale. A limited void is formed in the subterranean formation and zones of unfragmented formation are left above and below the void and are loaded with explosive for explosively expanding unfragmented formation toward the void. The explosive is placed into the zones of unfragmented formation for forming a substantially horizontal array of main explosive charges and at least one substantially horizontal array of satellite explosive charges. Each of the satellite explosive charges has a scaled point charge depth of burial substantially equal to the scaled point charge depth of burial of each of the main explosive charges and the actual depth of burial of each of the satellite explosive charges is less than the actual depth of burial of each of the main explosive charges. Explosive is detonated in the blastholes in a single round of explosions for explosively expanding at least one of the zones of unfragmented formation toward the void to form a fragmented permeable mass of formation particles containing oil shale in …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.