Triangular blasting into limited voids for vertical free face retorts

Patent · Tue Apr 21 00:00:00 EST 1981

OSTI ID:6300699

Ricketts, T E

Oil shale formation is explosively expanded toward a limited void volume for forming an in situ oil shale retort in a subterranean formation containing oil shale. In one embodiment, the retort is formed by excavating a narrow vertical slot diagonally across a retort site of rectangular horizontal crosssection, leaving separate triangular zones of unfragmented formation within the retort site on opposite sides of the diagonal slot. Explosive is placed in a plurality of vertical blasting holes drilled in each triangular zone of formation, and such explosive is detonated for explosively expanding formation within the triangular zones toward vertical free faces adjacent the slot for forming a fragmented permeable mass of formation particles containing oil shale. Detonation of explosive in the blasting holes expands separate wedge-shaped segments of formation toward the diagonal slot, owing to the natural cratering effect of each blast, causing the wedge-shaped segments being expanded to conform generally to the side boundaries of each triangular zone, and producing reasonably good fragmentation and movement of expanded formation toward the slot from formation throughout the retort site. Several such slots can be employed in forming a retort.

• Assignee: Occidental Oil Shale Inc
• Patent Number(s): US 4262965
• OSTI ID: 6300699
• Resource Relation: Patent File Date: Filed date 24 Sep 1979
• Country of Publication: United States
• Language: English

Related Subjects

04 OIL SHALES AND TAR SANDS
OIL SHALES
EXPLOSIVE FRACTURING
IN-SITU RETORTING
EXCAVATION
FRAGMENTATION
BITUMINOUS MATERIALS
CARBONACEOUS MATERIALS
CHEMICAL REACTIONS
COMMINUTION
DECOMPOSITION
ENERGY SOURCES
FOSSIL FUELS
FRACTURING
FUELS
IN-SITU PROCESSING
MATERIALS
PROCESSING
RETORTING
040401* - Oil Shales & Tar Sands- In Situ Methods
True & Modified