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Title: Downhole delay assembly for blasting with series delay

Abstract

A downhole delay assembly is provided which can be placed into a blasthole for initiation of explosive in the blasthole. The downhole delay assembly includes at least two detonating time delay devices in series in order to effect a time delay of longer than about 200 milliseconds in a round of explosions. The downhole delay assembly provides a protective housing to prevent detonation of explosive in the blasthole in response to the detonation of the first detonating time delay device. There is further provided a connection between the first and second time delay devices. The connection is responsive to the detonation of the first detonating time delay device and initiates the second detonating time delay device. A plurality of such downhole delay assemblies are placed downhole in unfragmented formation and are initiated simultaneously for providing a round of explosive expansions. The explosive expansions can be used to form an in situ oil shale retort containing a fragmented permeable mass of formation particles.

Inventors:
 [1]
  1. Grand Junction, CO
Issue Date:
OSTI Identifier:
864325
Patent Number(s):
4347789
Assignee:
Occidental Oil Shale, Inc. (Grand Junction, CO)
Patent Classifications (CPCs):
F - MECHANICAL ENGINEERING F42 - AMMUNITION F42D - BLASTING
DOE Contract Number:  
ET-77-A-03-1848
Resource Type:
Patent
Country of Publication:
United States
Language:
English
Subject:
downhole; delay; assembly; blasting; series; provided; placed; blasthole; initiation; explosive; detonating; time; devices; effect; 200; milliseconds; explosions; provides; protective; housing; prevent; detonation; response; device; connection; responsive; initiates; plurality; assemblies; unfragmented; formation; initiated; simultaneously; providing; expansions; form; situ; oil; shale; retort; containing; fragmented; permeable; mass; particles; permeable mass; formation particles; fragmented permeable; assembly provides; time delay; situ oil; shale retort; oil shale; unfragmented formation; downhole delay; delay device; delay assembly; /102/

Citation Formats

Ricketts, Thomas E. Downhole delay assembly for blasting with series delay. United States: N. p., 1982. Web.
Ricketts, Thomas E. Downhole delay assembly for blasting with series delay. United States.
Ricketts, Thomas E. Fri . "Downhole delay assembly for blasting with series delay". United States. https://www.osti.gov/servlets/purl/864325.
@article{osti_864325,
title = {Downhole delay assembly for blasting with series delay},
author = {Ricketts, Thomas E},
abstractNote = {A downhole delay assembly is provided which can be placed into a blasthole for initiation of explosive in the blasthole. The downhole delay assembly includes at least two detonating time delay devices in series in order to effect a time delay of longer than about 200 milliseconds in a round of explosions. The downhole delay assembly provides a protective housing to prevent detonation of explosive in the blasthole in response to the detonation of the first detonating time delay device. There is further provided a connection between the first and second time delay devices. The connection is responsive to the detonation of the first detonating time delay device and initiates the second detonating time delay device. A plurality of such downhole delay assemblies are placed downhole in unfragmented formation and are initiated simultaneously for providing a round of explosive expansions. The explosive expansions can be used to form an in situ oil shale retort containing a fragmented permeable mass of formation particles.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {1982},
month = {1}
}