US 4,300,800 A · Method of rubbling a pillar · patentgrep

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Abstract

Shale oil is recovered from a subterranean formation containing oil shale by excavating formation to form at least one void, leaving zones of unfragmented formation above and below each void and leaving at least one support pillar of unfragmented formation in the void. Explosive is placed in at least one of the zones of unfragmented formation for explosively expanding the zone of unfragmented formation toward the void. The pillar is prepared for explosive expansion by drilling substantially horizontal blastholes in the pillar and by loading explosive charges into the blastholes. Thereafter, the explosive charges are detonated in a single round of explosions for explosively expanding the pillar toward the void. At least one of the zones of unfragmented formation is then expanded toward the void to form a fragmented permeable mass of formation particles containing oil shale in an in situ oil shale retort. Gas is introduced into the fragmented permeable mass for establishing a retorting zone in the fragmented mass wherein oil shale is retorted to produce gaseous and liquid products and for advancing a retorting zone through the fragmented mass. Gaseous and liquid products are withdrawn from the retort.

Claims40

Dependent claims

A method of recovering shale oil from a subterranean formation containing oil shale which comprises the steps of:

(a) excavating formation to form at least one void in the subterranean formation leaving zones of unfragmented formation above and below each void, such a zone of unfragmented formation having a substantially horizontal free face adjoining such a void, and leaving at least one support pillar of unfragmented formation in such a void, each such support pillar having free faces on opposite sides of such pillar;
(b) placing explosive in at least one of such zones of unfragmented formation for explosively expanding such a zone of unfragmented formation;
(c) preparing such a support pillar for explosive expansion by a method comprising the steps of:
(i) drilling an array of spaced apart substantially horizontal blastholes in such a support pillar, such blastholes having axes substantially perpendicular to a free face of the pillar;
(ii) placing explosive charges into the blastholes;
(d) detonating explosive in a single round comprising:
(i) detonating explosive in the support pillar by detonating explosive in a blasthole at about the center of the blasthole array of such a support pillar first and thereafter detonating explosive in blastholes progressing towards the outer portion of the blasthole array for explosively expanding the support pillar toward the void;
(ii) detonating explosive in at least one of the zones of unfragmented formation for explosively explanding such a zone of unfragmented formation toward the void to form a fragmented permeable mass of formation particles containing oil shale in an in situ oil shale retort;
(e) introducing gas into the fragmented permeable mass in the in situ oil shale retort for establishing a retorting zone in the fragmented permeable mass wherein oil shale is retorted to produce gaseous and liquid products, and for advancing the retorting zone through the fragmented mass;
and
(f) withdrawing the gaseous and liquid products from the retort.

8 more elements

A method of recovering shale oil from a subterranean formation containing oil shale which comprises the steps of:

(a) excavating formation to form at least one void in the subterranean formation leaving zones of unfragmented formation above and below each void, such a zone of unfragmented formation having a substantially horizontal free face adjoining such a void, and leaving at least one generally rectangular support pillar of unfragmented formation in such a void, each such support pillar having a first and second long free face on opposite sides of such pillar;
(b) placing explosive in at least one of such zones of unfragmented formation for explosively expanding such a zone of unfragmented formation;
(c) preparing such a support pillar for explosive expansion by a method comprising the steps of:
(i) drilling an array of spaced apart substantially horizontal blastholes in such a support pillar, such blastholes having axes substantially perpendicular to a long free face of such support pillar;
(ii) placing explosive charges into the blastholes;
(d) detonating explosive in a single round comprising:
(i) detonating explosive in the support pillar by detonating explosive in a blasthole at about the center of the blasthole array of such a support pillar first and thereafter detonating explosive in blastholes progressing towards the outer portion of the blasthole array for explosively expanding the support pillar toward the void;
(ii) detonating explosive in at least one of the zones of unfragmented formation for explosively expanding such a zone of unfragmented formation toward the void to form a fragmented permeable mass of formation particles containing oil shale in an in situ oil shale retort;
(e) introducing gas into the fragmented permeable mass in the in situ oil shale retort for establishing a retorting zone in the fragmented permeable mass wherein oil shale is retorted to produce gaseous and liquid products, and for advancing the retorting zone through the fragmented mass;
and
(f) withdrawing the gaseous and liquid products from the retort.

8 more elements

A method of recovering shale oil from a subterranean formation containing oil shale which comprises the steps of:

(a) excavating formation to form at least one void in the subterranean formation leaving zones of unfragmented formation above and below each void, such a zone of unfragmented formation having a substantially horizontal free face adjoining such a void, and leaving at least one generally rectangular support pillar of unfragmented formation in such a void, each such support pillar having a first and second long free face on opposite sides of such support pillar;
(b) placing explosive in at least one of such zones of unfragmented formation for explosively expanding such a zone of unfragmented formation;
(c) preparing the support pillar for explosive expansion by a method comprising the steps of:
(i) drilling an array of spaced apart substantially horizontal blastholes in the support pillar, such blastholes having axes substantially perpendicular to a long free face of the support pillar;
(ii) placing explosive charges into the blastholes wherein each explosive charge is located in each blasthole for providing substantially equal burden distance from the center of mass of such an explosive charge to each of the long free faces of the support pillar;
(d) detonating explosive in a single round comprising:
(i) detonating explosive near the center of mass of each explosive charge in the blastholes in the support pillar for fragmenting and explosively expanding the support pillar toward the void, wherein explosive charges are detonated in a blasthole at about the center of the blasthole array first and, thereafter, explosive charges are detonated in blastholes progressing towards the outer portion of the blasthole array;
(ii) detonating explosive in at least one of the zones of unfragmented formation for explosively expanding such a zone of unfragmented formation toward the void to form a fragmented permeable mass of formation particles containing oil shale in an in situ oil shale retort;
(e) introducing gas to the fragmented permeable mass in the in situ oil shale retort for establishing a retorting zone in the fragmented permeable mass wherein oil shale is retorted to produce gaseous and liquid products, and for advancing the retorting zone through the fragmented mass;
and
(f) withdrawing the gaseous and liquid products from the retort.

8 more elements

A method of recovering shale oil from a subterranean formation containing oil shale which comprises the steps of:

(a) excavating formation to form at least one void in the subterranean formation leaving zones of unfragmented formation above and below each void, such a zone of unfragmented formation having a substantially horizontal free face adjoining the void, and leaving at least one generally rectangular support pillar of unfragmented formation in such a void, each such support pillar having a first and second long free face on opposite sides of such support pillar;
(b) placing explosive in at least one of such zones of unfragmented formation for explosively expanding such a zone of unfragmented formation;
(c) preparing the support pillar for explosive expansion by a method comprising the steps of:
(i) drilling a first array of spaced apart substantially horizontal blastholes in a first portion of such a support pillar, such blastholes having axes substantially perpendicular to the first and second long free faces of such support pillar;
(ii) drilling a second array of spaced apart blastholes in a second portion of such a support pillar, such blastholes having substantially horizontal axes wherein such axes are substantially parallel to the first and second long free faces of such support pillar;
(iii) placing explosive charges into the blastholes of the first array of spaced apart blastholes such that there is substantially equal burden distance from the center of mass of such an explosive charge to each of the long free faces of the support pillar;
and
(iv) placing explosive charges into the blastholes in the second array of spaced apart blastholes;
(d) detonating explosive in a single round comprising:
(i) detonating explosive in the blastholes of the support pillar, providing a time delay between at least a portion of such detonations of fragment and explosively expand the support pillar toward the void;
(ii) detonating explosive in at least one of the zones of unfragmented formation for explosively expanding such a zone of unfragmented permeable mass of formation toward the void to form a fragmented permeable mass of formation particles containing oil shale in an in situ oil shale retort;
(e) introducing gas to the fragmented permeable mass in the in situ oil shale retort for establishing a retorting zone in the fragmented permeable mass wherein oil shale is retorted to produce gaseous and liquid products, and for advancing the retorting zone through the fragmented mass;
and
(f) withdrawing the gaseous and liquid products from the retort.

11 more elements

A method of recovering shale oil from a subterranean formation containing oil shale which comprises the steps of:

(a) excavating to form at least one void in the subterranean formation leaving zones of unfragmented formation above and below each void, such zone of unfragmented formation having a substantially horizontal free face adjoining such a void, and leaving at least one support pillar of unfragmented formation in such a void, each such support pillar having free faces on opposite sides of such pillar;
(b) placing explosive in at least one of such zones of unfragmented formation for explosively expanding such a zone of unfragmented formation toward the void;
(c) preparing the support pillar for explosive expansion by a method comprising the steps of:
(i) drilling substantially horizontal blastholes in the support pillar wherein such blastholes have axes substantially perpendicular to a free face of the support pillar;
(ii) placing explosive charges into the blastholes wherein such explosive charges form at least three arrays comprising:
-a- a first substantially vertical array of explosive charges located such that the center of mass of each explosive charge in such first array is in a plane substantially perpendicular to the axes of the substantially horizontal blastholes;
-b- a second substantially vertical array of explosive charges located such that the center of mass of each explosive charge in such second array is in a plane substantially perpendicular to the axes of the substantially horizontal blastholes, such a plane at about the center of mass of the pillar;
-c- a third substantially vertical array of explosive charges located such that the center of mass of each explosive charge in such third array is located in a plane substantially perpendicular to the axes of the substantially horizontal blastholes;
(d) detonating explosive in a single round comprising:
(i) detonating explosive in blastholes of the first and third arrays of explosive charges, thereafter detonating explosive in blastholes of the second array of explosive charges;
(ii) detonating explosive in at least one of the zones of unfragmented formation for explosively expanding such a zone of formation toward the void to form a fragmented permeable mass of formation particles containing oil shale in an in situ oil shale retort;
(e) introducing gas to the fragmented permeable mass in the in situ oil shale retort for establishing a retorting zone in the fragmented permeable mass wherein oil shale is retorted to produce gaseous and liquid products, and for advancing the retorting zone through the fragmented mass;
and
(f) withdrawing the gaseous and liquid products from the retort.

11 more elements

A method of recovering shale oil from a subterranean formation containing oil shale which comprises the steps of:

(a) excavating formation to form at least one void in the subterranean formation leaving zones of unfragmented formation above and below each void, such zone of unfragmented formation having a substantially horizontal free face adjoining such a void, and leaving at least one generally rectangular support pillar of unfragmented formation in such a void, each such support pillar having a first and second long free face on opposite sides of such support pillar;
(b) placing explosive in at least one of such zones of unfragmented formation for explosively expanding such a zone of unfragmented formation toward the void;
(c) preparing the support pillar for explosive expansion by a method comprising the steps of:
(i) drilling substantially horizontal blastholes in the support pillar wherein such blastholes have axes substantially perpendicular to the first and second long free faces of the support pillar;
(ii) placing explosive charges into the blastholes wherein such explosive charges form at least three arrays comprising:
-a- a first substantially vertical array of explosive charges located such that the center of mass of each explosive charge in such first array is in a plane substantially parallel to the long free faces;
-b- a second substantially vertical array of explosive charges located such that the center of mass of each explosive charge in such second array is in a plane substantially parallel to the long free faces, such a plane at about the center of mass of the support pillar;
-c- a third substantially vertical array of explosive charges located such that the center of mass of each explosive charge in such third array is located in a plane substantially parallel to the long free faces;
(d) detonating explosive in a single round comprising:
(i) detonating explosive in blastholes of the first and third arrays of explosive charges, thereafter detonating explosive in blastholes of the second array of explosive charges;
(ii) detonating explosive in at least one of the zones of unfragmented formation for explosively expanding such a zone of formation toward the void to form a fragmented permeable mass of formation particles containing oil shale in an in situ oil shale retort;
(e) introducing gas to the fragmented permeable mass in the in situ oil shale retort for establishing a retorting zone in the fragmented permeable mass wherein oil shale is retorted to produce gaseous and liquid products, and for advancing the retorting zone through the fragmented mass;
and
(f) withdrawing the gaseous and liquid products from the retort.

11 more elements

A method of recovering shale oil from a subterranean formation containing oil shale which comprises the steps of:

(a) excavating formation to form at least one void in such a subterranean formation leaving zones of unfragmented formation above and below each void, each zone of unfragmented formation having a substantially horizontal free face adjoining such a void, and leaving at least one support pillar of unfragmented formation in such a void, each such support pillar having at least one set of parallel free faces on opposite sides of the support pillar;
(b) placing explosive in at least one of such zones of unfragmented formation for explosively expanding such a zone of unfragmented formation toward the void;
(c) preparing the support pillar for explosive expansion by a method comprising the steps of:
(i) drilling an array of spaced apart blastholes in the support pillar, such blastholes being substantially horizontal and having axes substantially parallel to such parallel free faces;
(ii) placing explosive charges into the blastholes;
(d) detonating explosive in a single round comprising:
(i) detonating explosive in blastholes near an outer portion of the blasthole array for explosively expanding formation between such blastholes and each of the parallel free faces for forming new free faces between the original free faces and a central portion of the support pillar;
(ii) thereafter detonating explosive in remaining blastholes of the blasthole array for explosively expanding the central portion of the support pillar towards such new free faces;
(iii) detonating explosive in at least one of the zones of unfragmented formation for explosively expanding such a zone of unfragmented formation toward the void to form a fragmented permeable mass of formation particles containing oil shale in the in situ oil shale retort;
(e) introducing gas into the fragmented permeable mass in the in situ oil shale retort for establishing a retort zone in the fragmented permeable mass wherein oil shale is retored to produce gaseous and liquid products, and for advancing the retorting zone through the fragmented mass;
and
(f) withdrawing the gaseous and liquid products from the retort;

9 more elements

A method of recovering shale oil from a subterranean formation containing oil shale which comprises the steps of:

(a) excavating formation to form at least one void in such a subterranean formation leaving zones of unfragmented formation above and below each void, each zone of unfragmented formation having a substantially horizontal free face adjoining such a void, and leaving at least one generally rectangular support pillar of unfragmented formation in such a void, each such support pillar having two long free faces;
(b) placing explosive in at least one of such zones of unfragmented formation for explosively expanding such a zone of unfragmented formation toward the void;
(c) preparing the support pillar for explosive expansion by a method comprising the steps of:
(i) drilling an array of spaced apart blastholes in the support pillar, such blastholes being substantially horizontal and having axes substantially parallel to the long free faces of the support pillar where the blastholes extend substantially the entire length of such a support pillar;
(ii) placing explosive charges into the blastholes;
(d) detonating explosive in a single round comprising:
(i) detonating explosive in blastholes near an outer portion of the blasthole array for explosively expanding formation between such blastholes and each of the parallel free faces for forming new free faces between the original free faces and a central portion of the support pillar;
(ii) thereafter detonating explosive in remaining blastholes of the blasthole array for explosively expanding the central portion of the support pillar towards such new free faces;
(iii) detonating explosive in at least one of the zones of unfragmented formation for explosively expanding such a zone of unfragmented formation toward the void to form a fragmented permeable mass of formation particles containing oil shale in the in situ oil shale retort;
(e) introducing gas into the fragmented permeable mass in the in situ oil shale retort for establishing a retorting zone in the fragmented permeable mass wherein oil shale is retorted to produce gaseous and liquid products, and for advancing the retorting zone through the fragmented mass;
and
(f) withdrawing the gaseous and liquid products from the retort.

9 more elements

A method of recovering shale oil from a subterranean formation containing oil shale which comprises the steps of:

(a) excavating formation to form at least one void in the subterranean formation leaving zones of unfragmented formation above and below each void, such a zone of unfragmented formation having a substantially horizontal free face adjoining such a void, and leaving at least one support pillar of unfragmented formation in such a void, each such support pillar having free faces on opposite sides of such support pillar;
(b) placing explosive in at least one of such zones of unfragmented formation for explosively expanding such a zone of unfragmented formation;
(c) preparing such a support pillar for explosive expansion by a method comprising the steps of:
(i) drilling an array of spaced apart substantially horizontal blastholes in the support pillar, such blastholes having axes substantially perpendicular to a free face of the support pillar;
and
(ii) placing explosive charges into the blastholes wherein each explosive charge is located in each blasthole for providing substantially equal burden distance from the center of mass of such an explosive charge to each of the free faces perpendicular to the axes of the blastholes, such explosive charges having a charge length of about 1/2 the thickness of the support pillar and a spacing distance less than about 3/8 the thickness of the support pillar;
(d) detonating explosive in a single round comprising:
(i) detonating explosive near the center of mass of each explosive charge in the blastholes in the support pillar wherein explosive charges are detonated substantially simultaneously for fragmenting and explosively expanding the pillar toward the void;
and
(ii) detonating explosive in at least one of the zones of unfragmented formation for explosively expanding such a zone of unfragmented formation toward the void to form a fragmented permeable mass of formation particles containing oil shale in an in situ oil shale retort;
(e) introducing gas to the fragmented permeable mass in the in situ oil shale retort for establishing a retorting zone in the fragmented permeable mass wherein oil shale is retorted to produce gaseous and liquid products, and for advancing the retorting zone through the fragmented mass;
and,
(f) withdrawing the gaseous and liquid products from the retort.

10 more elements

A method of recovering shale oil from a subterranean formation containing oil shale which comprises the steps of:

(a) excavating to form at least one void in the subterranean formation leaving zones of unfragmented formation above and below each void, such a zone of unfragmented formation having a substantially horizontal free face adjoining such a void, and leaving at least one generally rectangular support pillar of unfragmented formation in such a void, each such support pillar having a first and second long free face on opposite sides of such support pillar;
(b) placing explosive in at least one of such zones of unfragmented formation for explosively expanding such a zone of unfragmented formation;
(c) preparing such a support pillar for explosive expansion by a method comprising the steps of:
(i) drilling an array of spaced apart substantially horizontal blastholes in the support pillar, such blastholes having axes substantially perpendicular to a long free face of the support pillar;
and
(ii) placing explosive charges into the blastholes wherein each explosive charge is located in each blasthole for providing substantially equal burden distance from the center of mass of such an explosive charge to each of the long free faces of the support pillar, such explosive charges having a charge length of about 1/2 the thickness of the support pillar and a spacing distance less than about 3/8 the thickness of the support pillar;
(d) detonating explosive in a single round comprising:
(i) detonating explosive near the center of mass of each explosive charge in the blastholes in the support pillar wherein explosive charges are detonated substantially simultaneously for fragmenting and explosively expanding the support pillar toward the void;
and
(ii) detonating explosive in at least one of the zones of unfragmented formation for explosively expanding such a zone of unfragmented formation toward the void to form a fragmented permeable mass of formation particles containing oil shale in an in situ oil shale retort;
(e) introducing gas to the fragmented permeable mass in the in situ oil shale retort for establishing a retorting zone in the fragmented permeable mass wherein oil shale is retorted to produce gaseous and liquid products, and for advancing the retorting zone through the fragmented mass;
and
(f) withdrawing the gaseous and liquid products from the retort.

10 more elements

Dependencies are inferred from the claim text.