Explosive expansion to a limited void with uniform scaled depth of burial

摘要

A method is provided for recovering shale oil from a subterranean formation containing oil shale. Unfragmented formation is prepared for explosive expansion to form an oil shale retort by excavating at least one limited void in the subterranean formation and forming an array of spaced apart blastholes in the formation. A substantially horizontal array of explosive charges is formed by placing explosive into each blasthole wherein the scaled point charge depth of burial of the explosive charge in each blasthole is substantially equal to the equivalent scaled point charge depth of burial of the array of the explosive charges. Explosive charges are detonated in a single round for explosively expanding the unfragmented formation to form the in situ oil shale retort.PPRetorting is commenced and liquid and gaseous products of retorting are withdrawn from the retort.