Method of producing shale oil from an oil shale formation

Claim 1

A method of producing shale oil from a subterranean oil shale formation comprising the steps of: placing a relatively high energy explosive device within the formation; exploding the relatively high energy explosive device within the oil shale formation thereby forming a cavity within the oil shale formation having a roof beneath the overburden which subsequently collapses to form a chimney of rubble within the oil shale formation and extends fractures from the chimney through the oil shale formation; extending a plurality of spaced wells into said oil shale formation at locations radially outwardly from said chimney and adjacent to at least some of said fractures; forming fluid flow paths from said wells through said interconnecting fractures to said chimney; circulating fluid into and then from said wells and through said interconnecting fractures into said chimney and out of said chimney at rates creating a pressure drop from the wells to said chimney; imparting oil shale-reactive properties to said circulating fluid whereby said fluid reacts with said oil shale thereby moving solid components thereof into void spaced formed within said chimney thereby increasing the permeability of the oil shale formation relative to the permeability of the chimney in regions surrounding said chimney; extending a well into said chimney adjacent substantially the lower portion thereof; circulating said fluid from said plurality of wells through said fractures, into said chimney and out of said well; and producing fluid from said well at progressively higher places within said chimney.

Claim 2

A method of producing shale oil from a subterranean oil shale formation comprising the steps of: placing a relatively high energy explosive device within the formation; exploding the relatively high energy explosive device within the oil shale formation thereby forming a cavity within the oil shale formation having a roof beneath the overburden which subsequently collapses to form a chimney of rubble within the oil shale formation and and extends fractures from the chimney through the oil shale formation. extending a plurality of spaced wells into said oil shale formation at locations radially outwardly from said chimney and adjacent to at least some of said fractures; forming fluid flow paths from said wells through said interconnecting fractures to said chimney by electrically fracturing the portion of the oil shale formation between the chimney and said plurality of spaced wells; circulating fluid into and then from said wells and through said interconnecting fractures into said chimney and out of said chimney at rates creating a pressure drop from the wells to said chimney; and imparting oil shale-reactive properties to said circulating fluid whereby said fluid reacts with said oil shale thereby moving solid components thereof into void spaces formed within said chimney thereby increasing the permeability of the oil shale formation relative to the permeability of the chimney in regions surrounding said chimney.

Claim 3

A method of producing shale oil from a subterranean oil shale formation comprising the steps of: placing a relatively high energy explosive device within the formation; exploding the relatively high energy explosive device within the oil shale formation thereby forming a cavity within the oil shale formation having a roof beneath the overburden which subsequently collapses to form a chimney of rubble within the oil shale formation and extends fractures from the chimney through the oil shale formation; extending a plurality of spaced wells into said oil shale formation at locations radially outwardly from said chimney and adjacent to at least some of said fractures; forming fluid flow paths from said wells through said interconnecting fractures to said chimney; circulating fluid into and then from said wells and through said interconnecting fractures into said chimney and out of said chimney at rates creating a pressure drop from the wells to said chimney; imparting oil shale-reactive properties to said circulating fluid whereby said fluid reacts with said oil shale thereby moving solid components thereof into void spaces formed within said chimney thereby increasing the permeability of the oil shale formation relative to the permeability of the chimney in regions surrounding said chimney; stopping the circulating of fluid from said wells through said fractures and out of said chimney; and circulating fluid from said chimney through said fractures and out of said wells while imparting oil shale-reactive properties to said fluid circulating from said chimney and out of said wells.