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:
May. 06, 1980
Filed:
Aug. 21, 1978
Ned M Hutchins, Grand Junction, CO (US);
Occidental Oil Shale, Inc., Grand Junction, CO (US);
Abstract
An in situ oil shale retort is formed in a subterranean formation containing oil shale. Underground workings excavated within the formation provide a means for access to a retort site in the formation. At least one void is excavated in the retort site via access provided by the underground workings, leaving a remaining portion of the unfragmented formation within the retort site adjacent the void. Explosive placed in the remaining unfragmented formation adjacent such a void is detonated in a single round for explosively expanding the unfragmented formation toward such a void for forming a fragmented permeable mass of formation particles containing oil shale. Prior to such explosive expansion, a barrier of unfragmented formation is left between such a void and underground workings providing means for access to such a void. At least one gas flow passage extends through the barrier of unfragmented formation between the means for access and the retort site. Such a gas flow passage has a substantially smaller cross-section for gas flow than the transverse cross-section of the means for access to the retort site. The smaller cross-section of such a gas flow passage temporarily confines the high gas pressure generated by the explosion and limits the flow of gas to the means for access for attenuating airblast in the means for access and other underground workings in gas communication with the means for access.