The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Aug. 06, 1985
Filed:
Mar. 29, 1984
Thomas E Ricketts, Grand Junction, CO (US);
Occidental Oil Shale, Inc., Grand Junction, CO (US);
Abstract
An in situ oil shale retort containing a fragmented permeable mass of formation particles having a generally uniform permeability across horizontal cross-sections of the retort is provided. To form the retort, a void is excavated in a subterranean formation within the boundaries of the retort site, while at least one zone of unfragmented formation is left adjacent the void. A plurality of explosive charges are placed in the zone of unfragmented formation in a selected pattern; an array of central explosive charges and a plurality of perimeter charges arranged in rows surrounding the central charges. The spacing distance between each row of perimeter charges and an adjacent outer row of central charges is about equal. The combination of spacing distance and powder factor of the central charges is selected to produce a center portion of the fragmented permeable mass having a first average particle size (d.sub.1) and a first average void fraction (e.sub.1). The powder factor for each row of perimeter charges and the spacing distance between each outer row of central charges and an adjacent row of perimeter charges is selected to produce a perimeter portion of the fragmented permeable mass having a second particle size (d.sub.2) and a second void fraction (e.sub.2), the second average particle size (d.sub.2) and the second average void fraction (e.sub.2) being related to the first average particle size (d.sub.1) and the first average void fraction (e.sub.1) so that the relation ##EQU1## is in the range of from about 0.1 to 6.0.