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US4109964A Expired / Lapsed US ⏱️ 0.0 years remaining

Method for preconditioning oil shale preliminary to explosive expansion and in situ retorting thereof

Assignee: Occidental Oil Shale Inc
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Filing: 1977-01-03
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Granted: 1978-08-29
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Expires: 1997-01-03
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Abstract

Abstract A technique is provided for forming, in a subterranean deposit containing oil shale, an in situ oil shale retort having boundaries of unfragmented deposit containing a fragmented permeable mass of particles containing oil shale. The technique is particularly useful where at least a portion of the deposition layers of the oil shale deposit within the boundaries of the retort being formed are bonded together as a competent or relatively strong bed resistant to fragmenting. A portion of the deposit within the boundaries of the retort being formed is excavated to form a void with a free face within the boundaries. A second portion of the deposit within the boundaries extending away from the free face includes at least one competent bed. At least one competent bed within the boundaries is fractured substantially parallel to the deposition layers for reducing the effective thickness of the competent bed. The portion of the deposit within the boundaries of the retort being formed is then explosively expanded toward the void with a single round of explosives for fragmenting this portion of the deposit and forming a fragmented permeable mass of particles in an in situ oil shale retort. The fragmented mass is retorted to produce liquid and gaseous products including shale oil.

Inventors

  • 👤 Richard D. Ridley

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-11-08 18:24
CPC Classifications
E; E21; E21C; E21C41/00; E21C41/16; E21C41/24; E21B; E21B43/00; E21B43/16; E21B43/24; E21B43/243; E21B43/247; E21B43/248

Claims Analysis

Total Claims: 37
Claim 1
Independent Claim 224 words
A method of producing liquid and gaseous products including shale oil from an in situ oil shale retort containing a fragmented permeable mass of particles containing oil shale and having boundaries of subterranean deposit containing deposition layers of oil shale, wherein at least a portion of the deposition layers are bonded together as at least one competent bed, which comprises the steps of: excavating a first portion of the deposit from within the boundaries of the in situ oil shale retort being formed to form at least one void within said boundaries, the surface of the deposit defining such a void providing at least one free face extending through the deposit within said boundaries and leaving a second portion of the deposit within said boundaries extending away from such a free face, said second portion including at least one competent bed; fracturing such a competent bed in the second portion substantially parallel to the deposition layers for reducing the effective thickness of such competent bed; explosively expanding the second portion, including such a fractured bed, toward such a free face for forming a fragmented permeable mass of particles containing oil shale in an in situ oil shale retort being formed; and retorting the fragmented permeable mass containing oil shale in the in situ shale retort for producing liquid and gaseous products including shale oil.
Claim 2
Independent Claim 224 words
A method of producing liquid and gaseous products including shale oil from an in situ oil shale retort containing a fragmented permeable mass of particles containing oil shale and having boundaries of subterranean deposit containing deposition layers of oil shale, wherein at least a portion of the deposition layers are bonded together as at least one competent bed, which comprises the steps of: excavating a first portion of the deposit from within the boundaries of the in situ oil shale retort being formed to form at least one void within said boundaries, the surface of the deposit defining such a void providing at least one free face extending through the deposit within said boundaries and leaving a second portion of the deposit within said boundaries extending away from such a free face, said second portion including at least one competent bed; fracturing such a competent bed in the second portion substantially parallel to the deposition layers for reducing the effective thickness of such competent bed; explosively expanding the second portion, including such a fractured bed, toward such a free face for forming a fragmented permeable mass of particles containing oil shale in an in situ oil shale retort being formed; and retorting the fragmented permeable mass containing oil shale in the in situ shale retort for producing liquid and gaseous products including shale oil.
Claim 3
Independent Claim 272 words
A method of producing liquid and gaseous products including shale oil from an in situ oil shale retort containing a fragmented permeable mass of particles containing oil shale and having boundaries of subterranean deposit containing deposition layers of oil shale, wherein at least a portion of the deposition layers are bonded together as at least one competent bed, which comprises the steps of: excavating a first portion of the deposit from within the boundaries of the in situ oil shale retort being formed to form at least one void within said boundaries, the surface of the deposit defining such a void providing at least one free face extending through the deposit within said boundaries and leaving a second portion of the deposit within said boundaries extending away from such a free face, said second portion including at least one competent bed, wherein the first portion of the deposit is excavated adjacent the lower boundary of the in situ oil shale retort leaving the second portion including at least one competent bed above the excavated void for providing a horizontally extending free face defined by the overlying second portion; fracturing such a competent bed in the second portion substantially parallel to the deposition layers for reducing the effective thickness of such competent bed; explosively expanding the second portion, including such a fractured bed, toward such a free face for forming a fragmented permeable mass of particles containing oil shale in an in situ oil shale retort being formed; and retorting the fragmented permeable mass containing oil shale in the in situ oil shale retort for producing liquid and gaseous products including shale oil.
Claim 4
Independent Claim 272 words
A method of producing liquid and gaseous products including shale oil from an in situ oil shale retort containing a fragmented permeable mass of particles containing oil shale and having boundaries of subterranean deposit containing deposition layers of oil shale, wherein at least a portion of the deposition layers are bonded together as at least one competent bed, which comprises the steps of: excavating a first portion of the deposit from within the boundaries of the in situ oil shale retort being formed to form at least one void within said boundaries, the surface of the deposit defining such a void providing at least one free face extending through the deposit within said boundaries and leaving a second portion of the deposit within said boundaries extending away from such a free face, said second portion including at least one competent bed, wherein the first portion of the deposit is excavated adjacent the lower boundary of the in situ oil shale retort leaving the second portion including at least one competent bed above the excavated void for providing a horizontally extending free face defined by the overlying second portion; fracturing such a competent bed in the second portion substantially parallel to the deposition layers for reducing the effective thickness of such competent bed; explosively expanding the second portion, including such a fractured bed, toward such a free face for forming a fragmented permeable mass of particles containing oil shale in an in situ oil shale retort being formed; and retorting the fragmented permeable mass containing oil shale in the in situ oil shale retort for producing liquid and gaseous products including shale oil.
Claim 5
Dependent Claim 58 words
A method of producing liquid and gaseous products as recited in claim 2 wherein the second portion of the deposit above the horizontally extending free face is explosively expanded by: drilling a plurality of blasting holes vertically from the free face into said second portion of the deposit; loading explosive into the blasting holes; and detonating the explosive.
Claim 6
Independent Claim 263 words
A method of producing liquid and gaseous products including shale oil from an in situ oil shale retort containing a fragmented permeable mass of particles containing oil shale and having boundaries of subterranean deposit containing deposition layers of oil shale, wherein at least a portion of the deposition layers are bonded together as at least one competent bed, which comprises the steps of: excavating a first portion of the deposit from within the boundaries of the in situ shale retort being formed to form at least one void within said boundaries, the surface of the deposit defining such a void providing at least one free face extending through the deposit within said boundaries and leaving a second portion of the deposit within said boundaries extending away from such a free face, said second portion including at least one competent bed; fracturing such a competent bed in the second portion substantially parallel to the deposition layers for reducing the effective thickness of such competent bed; explosively expanding the second portion, including such a fractured bed, toward such a free face for forming a fragmented permeable mass of particles containing oil shale in an in situ oil shale retort being formed; and retorting the fragmented permeable mass containing oil shale in the in situ oil shale retort for producing liquid and gaseous products including shale oil and wherein at least one such competent bed is fractured by drilling a plurality of holes into the competent bed and fracturing the competent bed from a plurality of such holes at the same level in the competent bed.
Claim 7
Independent Claim 263 words
A method of producing liquid and gaseous products including shale oil from an in situ oil shale retort containing a fragmented permeable mass of particles containing oil shale and having boundaries of subterranean deposit containing deposition layers of oil shale, wherein at least a portion of the deposition layers are bonded together as at least one competent bed, which comprises the steps of: excavating a first portion of the deposit from within the boundaries of the in situ shale retort being formed to form at least one void within said boundaries, the surface of the deposit defining such a void providing at least one free face extending through the deposit within said boundaries and leaving a second portion of the deposit within said boundaries extending away from such a free face, said second portion including at least one competent bed; fracturing such a competent bed in the second portion substantially parallel to the deposition layers for reducing the effective thickness of such competent bed; explosively expanding the second portion, including such a fractured bed, toward such a free face for forming a fragmented permeable mass of particles containing oil shale in an in situ oil shale retort being formed; and retorting the fragmented permeable mass containing oil shale in the in situ oil shale retort for producing liquid and gaseous products including shale oil and wherein at least one such competent bed is fractured by drilling a plurality of holes into the competent bed and fracturing the competent bed from a plurality of such holes at the same level in the competent bed.
Claim 8
Independent Claim 258 words
A method of producing liquid and gaseous product including shale oil from an in situ oil shale retort containing a fragmented permeable mass of particles containing oil shale and having boundaries of subterranean deposit containing deposition layers of oil shale, wherein at least a portion of the deposition layers are bonded together as at least one competent bed, which comprises the steps of: excavating a first portion of the deposit from within the boundaries of the in situ oil shale retort being formed to form at least one void within said boundaries, the surface of the deposit defining such a void providing at least one free face extending vertically through the deposit within the boundaries and leaving a second portion of the deposit within said boundaries extending away from such a free face, said second portion including at least one competent bed; fracturing such a competent bed in the second portion substantially parallel to the deposition layers for reducing the effective thickness of such competent bed; drilling a plurality of blasting holes in said second portion of the deposit parallel to the free face; loading explosive into the blasting holes; detonating the explosive in a single round for explosively expanding the second portion, including such a fractured bed, toward such a free face for forming a fragmented permeable mass of particles containing oil shale in an in situ oil shale retort being formed; and retorting the fragmented permeable mass containing oil shale in the in situ oil shale retort for producing liquid and gaseous products including shale oil.
Claim 9
Independent Claim 258 words
A method of producing liquid and gaseous product including shale oil from an in situ oil shale retort containing a fragmented permeable mass of particles containing oil shale and having boundaries of subterranean deposit containing deposition layers of oil shale, wherein at least a portion of the deposition layers are bonded together as at least one competent bed, which comprises the steps of: excavating a first portion of the deposit from within the boundaries of the in situ oil shale retort being formed to form at least one void within said boundaries, the surface of the deposit defining such a void providing at least one free face extending vertically through the deposit within the boundaries and leaving a second portion of the deposit within said boundaries extending away from such a free face, said second portion including at least one competent bed; fracturing such a competent bed in the second portion substantially parallel to the deposition layers for reducing the effective thickness of such competent bed; drilling a plurality of blasting holes in said second portion of the deposit parallel to the free face; loading explosive into the blasting holes; detonating the explosive in a single round for explosively expanding the second portion, including such a fractured bed, toward such a free face for forming a fragmented permeable mass of particles containing oil shale in an in situ oil shale retort being formed; and retorting the fragmented permeable mass containing oil shale in the in situ oil shale retort for producing liquid and gaseous products including shale oil.
Claim 10
Independent Claim 268 words
A method of producing liquid and gaseous products including shale oil from an in situ oil shale retort containing a fragmented permeable mass of particles containing oil shale and having boundaries of subterranean deposit containing deposition layers of oil shale, wherein at least a portion of the deposition layers are bonded together as at least one competent bed, which comprises the steps of: excavating a first portion of the deposit from within the boundaries of the in situ oil shale retort being formed to form at least one void within said boundaries, the surface of the deposit defining such a void providing at least one free face extending through the deposit within said boundaries and leaving a second portion of the deposit within said boundaries extending away from such a free face, said second portion including at least one competent bed; fracturing such a competent bed in the second portion substantially parallel to the deposition layers for reducing the effective thickness of such competent bed; explosively expanding the second portion, including such a fractured bed, toward such a free face for forming a fragmented permeable mass of particles containing oil shale in an in situ oil shale retort being formed; and retorting the fragmented permeable mass containing oil shale in the in situ oil shale retort for producing liquid and gaseous products including shale oil; and wherein the volume of the excavated first portion within the boundaries of the in situ retort being formed is in the range of from about 10 to 25% of the total volume within the boundaries of the in situ retort being formed.
Claim 11
Independent Claim 268 words
A method of producing liquid and gaseous products including shale oil from an in situ oil shale retort containing a fragmented permeable mass of particles containing oil shale and having boundaries of subterranean deposit containing deposition layers of oil shale, wherein at least a portion of the deposition layers are bonded together as at least one competent bed, which comprises the steps of: excavating a first portion of the deposit from within the boundaries of the in situ oil shale retort being formed to form at least one void within said boundaries, the surface of the deposit defining such a void providing at least one free face extending through the deposit within said boundaries and leaving a second portion of the deposit within said boundaries extending away from such a free face, said second portion including at least one competent bed; fracturing such a competent bed in the second portion substantially parallel to the deposition layers for reducing the effective thickness of such competent bed; explosively expanding the second portion, including such a fractured bed, toward such a free face for forming a fragmented permeable mass of particles containing oil shale in an in situ oil shale retort being formed; and retorting the fragmented permeable mass containing oil shale in the in situ oil shale retort for producing liquid and gaseous products including shale oil; and wherein the volume of the excavated first portion within the boundaries of the in situ retort being formed is in the range of from about 10 to 25% of the total volume within the boundaries of the in situ retort being formed.
Claim 12
Independent Claim 201 words
A method of forming an in situ oil shale retort in a subterranean deposit containing deposition layers of oil shale, said in situ retort containing a fragmented permeable mass of particles containing oil shale and having boundaries of said deposit, wherein at least a portion of the deposition layers are bonded together as at least one competent bed, which comprises the steps of: excavating a first portion of the deposit from within the boundaries of the in situ oil shale retort being formed to form at least one void within said boundaries, the surface of the deposit defining such a void providing at least one free face extending through the deposit within said boundaries and leaving a second portion of the deposit within said boundaries extending away from such a free face, said second portion including at least one competent bed; fracturing such a competent bed in the second portion substantially parallel to the deposition layers for reducing the effective thickness of such competent bed; and explosively expanding the second portion, including such a fractured bed, toward such a free face for forming a fragmented permeable mass of particles containing oil shale in an in situ oil shale retort being formed.
Claim 13
Independent Claim 201 words
A method of forming an in situ oil shale retort in a subterranean deposit containing deposition layers of oil shale, said in situ retort containing a fragmented permeable mass of particles containing oil shale and having boundaries of said deposit, wherein at least a portion of the deposition layers are bonded together as at least one competent bed, which comprises the steps of: excavating a first portion of the deposit from within the boundaries of the in situ oil shale retort being formed to form at least one void within said boundaries, the surface of the deposit defining such a void providing at least one free face extending through the deposit within said boundaries and leaving a second portion of the deposit within said boundaries extending away from such a free face, said second portion including at least one competent bed; fracturing such a competent bed in the second portion substantially parallel to the deposition layers for reducing the effective thickness of such competent bed; and explosively expanding the second portion, including such a fractured bed, toward such a free face for forming a fragmented permeable mass of particles containing oil shale in an in situ oil shale retort being formed.
Claim 14
Independent Claim 212 words
A method of forming an in situ oil shale retort in a subterranean deposit containing deposition layers of oil shale, said in situ retort containing a fragmented permeable mass of particles containing oil shale and having boundaries of said deposit, wherein at least a portion of the deposition layers are bonded together as at least one competent bed, which comprises the steps of: excavating a first portion of the deposit adjacent the lower boundary and from within the boundaries of the in situ oil shale retort being formed to form at least one void within said boundaries, the surface of the deposit defining such a void providing at least one horizontally extending free face extending through the deposit within said boundaries and leaving a second portion of the deposit within said boundaries extending away from such a free face, said second portion including at least one competent bed, above the excavated void; fracturing such a competent bed in the second portion substantially parallel to the deposition layers for reducing the effective thickness of such competent bed; and explosively expanding the second portion, including such a fractured bed, toward such a free face for forming a fragmented permeable mass of particles containing oil shale in an in situ oil shale retort being formed.
Claim 15
Independent Claim 212 words
A method of forming an in situ oil shale retort in a subterranean deposit containing deposition layers of oil shale, said in situ retort containing a fragmented permeable mass of particles containing oil shale and having boundaries of said deposit, wherein at least a portion of the deposition layers are bonded together as at least one competent bed, which comprises the steps of: excavating a first portion of the deposit adjacent the lower boundary and from within the boundaries of the in situ oil shale retort being formed to form at least one void within said boundaries, the surface of the deposit defining such a void providing at least one horizontally extending free face extending through the deposit within said boundaries and leaving a second portion of the deposit within said boundaries extending away from such a free face, said second portion including at least one competent bed, above the excavated void; fracturing such a competent bed in the second portion substantially parallel to the deposition layers for reducing the effective thickness of such competent bed; and explosively expanding the second portion, including such a fractured bed, toward such a free face for forming a fragmented permeable mass of particles containing oil shale in an in situ oil shale retort being formed.
Claim 16
Dependent Claim 62 words
A method of forming an in situ oil shale retort as recited in claim 8 wherein such a competent bed in the second portion of the deposit is fractured by drilling a plurality of fracturing holes into such a competent bed in the second portion from the void formed by excavating said first portion, and fracturing such competent bed from said void.
Claim 17
Dependent Claim 60 words
A method of forming an in situ oil shale retort as recited in claim 8 wherein the second portion of the deposit above the horizontally extending free face is explosively expanded by; drilling a plurality of blasting holes vertically from the free face into said second portion of the deposit; loading explosive into the blasting holes; and detonating the explosive.
Claim 18
Independent Claim 239 words
A method of forming an in situ oil shale retort in a subterranean deposit containing deposition layers of oil shale, said in situ retort containing a fragmented permeable mass of particles containing oil shale and having boundaries of said deposit, wherein at least a portion of the deposition layers are bonded together as at least one competent bed, which comprises the steps of: excavating a first portion of the deposit from within the boundaries of the in situ oil shale retort being formed to form at least one void within said boundaries, the surface of the deposit defining such a void providing at least one free face extending through the deposit within said boundaries and leaving a second portion of the deposit within said boundaries extending away from such a free face, said second portion including at least one competent bed; fracturing such a competent bed in the second portion substantially parallel to the deposition layers for reducing the effective thickness of such competent bed; and explosively expanding the second portion, including such a fractured bed, toward such a free face for forming a fragmented permeable mass of particles containing oil shale in an in situ oil shale retort being formed; and wherein at least one competent bed is fractured by drilling a plurality of holes into the competent bed and fracturing the competent bed from a plurality of such holes at the same level in the competent bed.
Claim 19
Independent Claim 239 words
A method of forming an in situ oil shale retort in a subterranean deposit containing deposition layers of oil shale, said in situ retort containing a fragmented permeable mass of particles containing oil shale and having boundaries of said deposit, wherein at least a portion of the deposition layers are bonded together as at least one competent bed, which comprises the steps of: excavating a first portion of the deposit from within the boundaries of the in situ oil shale retort being formed to form at least one void within said boundaries, the surface of the deposit defining such a void providing at least one free face extending through the deposit within said boundaries and leaving a second portion of the deposit within said boundaries extending away from such a free face, said second portion including at least one competent bed; fracturing such a competent bed in the second portion substantially parallel to the deposition layers for reducing the effective thickness of such competent bed; and explosively expanding the second portion, including such a fractured bed, toward such a free face for forming a fragmented permeable mass of particles containing oil shale in an in situ oil shale retort being formed; and wherein at least one competent bed is fractured by drilling a plurality of holes into the competent bed and fracturing the competent bed from a plurality of such holes at the same level in the competent bed.
Claim 20
Independent Claim 234 words
A method of forming an in situ oil shale retort in a subterranean deposit containing deposition layers of oil shale, said in situ retort containing a fragmented permeable mass of particles containing oil shale and having boundaries of said deposit, wherein at least a portion of the deposition layers are bonded together as at least one competent bed, which comprises the steps of: excavating a first portion of the deposit from within the boundaries of the in situ oil shale retort being formed to form at least one void within said boundaries, the surface of the deposit defining such a void providing at least one free face extending vertically through the deposit within the boundaries and leaving a second portion of the deposit within said boundaries extending away from such a free face, said second portion including at least one competent bed; fracturing such a competent bed in the second portion substantially parallel to the deposition layers for reducing the effective thickness of such competent bed; drilling a plurality of blasting holes in said second portion of the deposit parallel to the free face; loading explosive into the blasting holes; and detonating the explosive in a single round for explosively expanding the second portion, including such a fractured bed, toward such a free face for forming a fragmented permeable mass of particles containing oil shale in an in situ oil shale retort being formed.
Claim 21
Independent Claim 234 words
A method of forming an in situ oil shale retort in a subterranean deposit containing deposition layers of oil shale, said in situ retort containing a fragmented permeable mass of particles containing oil shale and having boundaries of said deposit, wherein at least a portion of the deposition layers are bonded together as at least one competent bed, which comprises the steps of: excavating a first portion of the deposit from within the boundaries of the in situ oil shale retort being formed to form at least one void within said boundaries, the surface of the deposit defining such a void providing at least one free face extending vertically through the deposit within the boundaries and leaving a second portion of the deposit within said boundaries extending away from such a free face, said second portion including at least one competent bed; fracturing such a competent bed in the second portion substantially parallel to the deposition layers for reducing the effective thickness of such competent bed; drilling a plurality of blasting holes in said second portion of the deposit parallel to the free face; loading explosive into the blasting holes; and detonating the explosive in a single round for explosively expanding the second portion, including such a fractured bed, toward such a free face for forming a fragmented permeable mass of particles containing oil shale in an in situ oil shale retort being formed.
Claim 22
Independent Claim 207 words
A method of forming an in situ oil shale retort in a subterranean deposit containing deposition layers of oil shale, said in situ retort containing a fragmented permeable mass of particles containing oil shale and having boundaries of said deposit, wherein at least a portion of the deposition layers are bonded together as at least one competent bed, which comprises the steps of: excavating a first portion of the deposit from within the boundaries of the in situ oil shale retort being formed to form at least one void within said boundaries, the surface of the deposit defining such a void providing at least one free face extending through the deposit within said boundaries and leaving a second portion of the deposit within said boundaries extending away from such a free face, said second portion including at least one competent bed; fracturing from an underground base of operation such a competent bed in the second portion substantially parallel to the deposition layers for reducing the effective thickness of such competent bed; and explosively expanding the second portion, including such a fractured bed, toward such a free face for forming a fragmented permeable mass of particles containing oil shale in an in situ oil shale retort being formed.
Claim 23
Independent Claim 207 words
A method of forming an in situ oil shale retort in a subterranean deposit containing deposition layers of oil shale, said in situ retort containing a fragmented permeable mass of particles containing oil shale and having boundaries of said deposit, wherein at least a portion of the deposition layers are bonded together as at least one competent bed, which comprises the steps of: excavating a first portion of the deposit from within the boundaries of the in situ oil shale retort being formed to form at least one void within said boundaries, the surface of the deposit defining such a void providing at least one free face extending through the deposit within said boundaries and leaving a second portion of the deposit within said boundaries extending away from such a free face, said second portion including at least one competent bed; fracturing from an underground base of operation such a competent bed in the second portion substantially parallel to the deposition layers for reducing the effective thickness of such competent bed; and explosively expanding the second portion, including such a fractured bed, toward such a free face for forming a fragmented permeable mass of particles containing oil shale in an in situ oil shale retort being formed.
Claim 24
Dependent Claim 39 words
A method of forming an in situ oil shale retort as recited in claim 13 wherein the base of operation is above the second portion to be explosively expanded and fracturing holes are drilled downwardly into said second portion.
Claim 25
Dependent Claim 39 words
A method of forming an in situ oil shale retort as recited in claim 13 wherein the base of operation is below the second portion to be explosively expanded and fracturing holes are drilled upwardly into said second portion.
Claim 26
Independent Claim 201 words
A method of forming an in situ oil shale retort in a subterranean deposit containing deposition layers of oil shale, said in situ oil shale retort containing a fragmented permeable mass of particles containing oil shale and having boundaries of said deposit, wherein at least a portion of the deposition layers are bonded together as at least one competent bed, which comprises the steps of: excavating a first portion of the deposit from within the boundaries of the in situ oil shale retort being formed to form at least one void beneath a second portion of the deposit left within the boundaries, the surface of the second portion adjacent such a void defining a horizontally extending free face, said second portion including at least one competent bed; fracturing a part of the second portion that acts as a competent bed and which is to be expanded in the in situ oil shale retort while leaving at least one competent bed unfractured adjacent such a horizontally extending free face; and explosively expanding the second portion including such a fractured bed toward such a void for forming a fragmented permeable mass of particles containing oil shale in the in situ oil shale retort.
Claim 27
Independent Claim 201 words
A method of forming an in situ oil shale retort in a subterranean deposit containing deposition layers of oil shale, said in situ oil shale retort containing a fragmented permeable mass of particles containing oil shale and having boundaries of said deposit, wherein at least a portion of the deposition layers are bonded together as at least one competent bed, which comprises the steps of: excavating a first portion of the deposit from within the boundaries of the in situ oil shale retort being formed to form at least one void beneath a second portion of the deposit left within the boundaries, the surface of the second portion adjacent such a void defining a horizontally extending free face, said second portion including at least one competent bed; fracturing a part of the second portion that acts as a competent bed and which is to be expanded in the in situ oil shale retort while leaving at least one competent bed unfractured adjacent such a horizontally extending free face; and explosively expanding the second portion including such a fractured bed toward such a void for forming a fragmented permeable mass of particles containing oil shale in the in situ oil shale retort.
Claim 28
Dependent Claim 62 words
A method of forming an in situ oil shale retort as recited in claim 16 wherein such a competent bed in the second portion of the deposit is fractured by drilling a plurality of fracturing holes into such a competent bed in the second portion from the void formed by excavating said first portion, and fracturing such competent bed from said void.
Claim 29
Dependent Claim 38 words
A method of forming an in situ oil shale retort as recited in claim 17 wherein at least one competent bed is fractured from a plurality of such fracturing holes at the same level in the competent bed.
Claim 30
Independent Claim 190 words
A method of forming an in situ oil shale retort in a subterranean deposit containing deposition layers of oil shale, said in situ retort containing a fragmented permeable mass of particles containing oil shale and having boundaries of said deposit, wherein at least a portion of the deposition layers are bonded together as at least one competent bed, which comprises the steps of: fracturing at least one portion of the deposit that acts as a competent bed; excavating a first portion of the deposit from within the boundaries of the in situ oil shale retort being formed to form at least one void within said boundaries, the surface of the deposit defining such a void providing at least one free face extending vertically through the deposit within said boundaries, and leaving a second portion of the deposit within said boundaries extending away from such a free face, said second portion including at least one fractured portion; and explosively expanding the second portion, including such a fractured portion, toward such a free face for forming a fragmented permeable mass of particles containing oil shale in an in situ oil shale retort.
Claim 31
Independent Claim 190 words
A method of forming an in situ oil shale retort in a subterranean deposit containing deposition layers of oil shale, said in situ retort containing a fragmented permeable mass of particles containing oil shale and having boundaries of said deposit, wherein at least a portion of the deposition layers are bonded together as at least one competent bed, which comprises the steps of: fracturing at least one portion of the deposit that acts as a competent bed; excavating a first portion of the deposit from within the boundaries of the in situ oil shale retort being formed to form at least one void within said boundaries, the surface of the deposit defining such a void providing at least one free face extending vertically through the deposit within said boundaries, and leaving a second portion of the deposit within said boundaries extending away from such a free face, said second portion including at least one fractured portion; and explosively expanding the second portion, including such a fractured portion, toward such a free face for forming a fragmented permeable mass of particles containing oil shale in an in situ oil shale retort.
Claim 32
Dependent Claim 47 words
A method of forming an in situ oil shale retort as recited in claim 19 further comprising the step of excavating an underground base of operation above the second portion to be explosively expanded, and wherein the fracturing step is conducted from said underground base of operation.
Claim 33
Independent Claim 143 words
A method of forming an in situ oil shale retort wherein oil shale adjacent to a void excavated in an oil shale deposit is explosively expanded toward a free face on deposit adjacent the void to form the in situ oil shale retort, and further wherein certain deposition layers of oil shale in the deposit within which the in situ oil shale retort is to be formed are bonded together as competent beds which comprise the steps of: fracturing through at least a portion of the competent beds in the portion to become the in situ oil shale retort to reduce the strength of the competent beds and separate the competent beds into thinner beds, and thereafter, explosively expanding the oil shale including a fractured portion of a competent bed toward such a free face to form the in situ oil shale retort.
Claim 34
Independent Claim 143 words
A method of forming an in situ oil shale retort wherein oil shale adjacent to a void excavated in an oil shale deposit is explosively expanded toward a free face on deposit adjacent the void to form the in situ oil shale retort, and further wherein certain deposition layers of oil shale in the deposit within which the in situ oil shale retort is to be formed are bonded together as competent beds which comprise the steps of: fracturing through at least a portion of the competent beds in the portion to become the in situ oil shale retort to reduce the strength of the competent beds and separate the competent beds into thinner beds, and thereafter, explosively expanding the oil shale including a fractured portion of a competent bed toward such a free face to form the in situ oil shale retort.
Claim 35
Dependent Claim 50 words
A method of producing liquid and gaseous products as recited in claim 2 in which a lowermost competent bed above the horizontally extending free face is left sufficiently competent to maintain a ceiling above the excavated void with sufficient strength not to cave in of its own accord after fracturing.
Claim 36
Dependent Claim 50 words
A method of producing liquid and gaseous products as recited in claim 8 in which a lowermost competent bed above the horizontally extending free face is left sufficiently competent to maintain a ceiling above the excavated void with sufficient strength not to cave in of its own accord after fracturing.
Claim 37
Dependent Claim 35 words
A method of forming an in situ oil shale retort as recited in claim 7 wherein the total void volume of the fragmented mass is substantially the same as the volume of the evcavated void.

References Cited (Backward Citations)

US3233668A Cited
US3464490A Cited
US3593788A Cited
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US3677342A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1981-08-28 1982-02-27 1982-08-29 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1985-08-28 1986-02-27 1986-08-29 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1989-08-28 1990-02-27 1990-08-29 $7700.00 Window Closed / Lapsed

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