Abstract: Formation is excavated from an in situ oil shale retort site for forming at least one void within the retort site, leaving at least one remaining zone of unfragmented formation within the retort site adjacent such a void. The remaining zone is explosively expanded toward such a void for forming a fragmented permeable mass of formation particles containing oil shale in an in situ oil shale retort. Oil shale in the in situ retort is retorted to produce liquid and gaseous products, leaving a mass of spent oil shale particles in the in situ retort. Oil shale particles excavated from the in situ retort site are separately retorted, such as in a surface retorting operation, producing liquid and gaseous products and spent surface retorted oil shale particles. The spent surface retorted particles are disposed of by forming an aqueous slurry of the particles, and pumping the slurry into a spent in situ retort.

Abstract: A ventilation and process air distribution system is provided for an in situ oil shale retort system which includes a production region having a cluster of retorts producing gaseous and liquid products and a retort preparation region where in situ retorts are being prepared for production. An underground air delivery drift system distributes process air to the production region and ventilation air to underground workings in the retort preparation region. A liquid collection drift system extends at or below the bottoms of the retorts in the production region and in the retort preparation region. The liquid collection drifts connect to an exhaust airway leading above ground and having an induction fan for inducing ventilation air to flow through the retort preparation region at a pressure lower than ambient air pressure above ground.

Abstract: A method of mining an oil-bearing bed with bottom water, wherein a plurality of underground workings and at least one working gallery are arranged. Inlet and recovery wells are drilled from the gallery. A heat carrier is force-fed into the oil-bearing bed for heating the latter through the inlet wells. Oil is extracted from the recovery wells to the working gallery and delivered via the workings to the ground surface. While so doing, additional wells are drilled from the working gallery in the water-bearing portion of the bed in the zone of oil contact with bottom water and, simultaneously with the injection of the heat carrier into the inlet wells and extraction of oil from the recovery wells, water is extracted through the additional wells.

Abstract: A method for the in situ processing of oil shale ore includes the establishment of underground stopes by removing from each a portion of the oil shale ore therein, rubblizing the remaining ore in each stope, extracting the rubblized ore and crushing it to obtain a desired particle size for subsequent processing, and restoring the sized oil shale particles to the stope by backfilling the stope as the rubble is extracted. The stope is maintained substantially filled with ore to provide lateral support to the side walls and reduce the likelihood of caving in the stope. The oil shale is retorted by injection of hot gas into the stope, and residual carbon is recovered from the retorted ore as producer fuel gas. The sensible heat in the ore may thereafter be recovered for use in retorting oil shale ore in an adjacent stope.

Abstract: A generally flat combustion zone is formed across the entire horizontal cross-section of a fragmented permeable mass of formation particles formed in an in situ oil shale retort. The flat combustion zone is formed by either sequentially igniting regions of the surface of the fragmented permeable mass at successively lower elevations or by igniting the entire surface of the fragmented permeable mass and controlling the rate of advance of various portions of the combustion zone.

Abstract: A modified in-situ retort for the retorting of oil shale is constructed by mining an open space having a volume of twenty-five to thirty-five percent of the volume of the retort in the bottom of the retort and thereafter blasting the oil shale that is to remain in the retort as rubble in a manner to cause random free fall of the shale particles onto the rubblized bed. Blasting occurs sequentially from the bottom of the unfragmented shale immediately above the open space to the top of the retort. At each blast, there is an open space below the shale to be broken in the blast having a volume at least one-third the volume of that shale, and the timing of the blasts is such that movement of the broken shale is not interfered with by shale broken in the preceding blast. There is no withdrawal of oil shale that would cause downward movement of the rubble that is to be retorted in-situ. The resultant in-situ retort is characterized by a high and uniform permeability.

Abstract: This invention relates to a method of recovering shale oil from a subterranean formation containing oil shale. Unfragmented formation is explosively expanded in a single round of explosions for moving formation located at about the center of a zone of unfragmented formation a greater distance in a given time interval after the beginning of the round than formation located in the unfragmented formation outward from about the center of the unfragmented formation.The explosive expansion forms a fragmented mass of formation particles containing oil shale in the subterranean formation forming an in situ oil shale retort.Gas is introduced 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. Gaseous and liquid products are withdrawn from the bottom of the retort.

Abstract: A temporary gas seal is provided in a gas level drift of an in situ oil shale retort system which includes a production region having a panel of retorts producing gaseous and liquid products and an adjacent retort preparation region where a panel of in situ retorts is being prepared for production. A portion of the gas level drift is connected to the active retorts for withdrawing off gas while adjacent portions of the gas level drift are being developed. Portions of the gas level connected to the active retorts are temporarily sealed by a gas isolation barrier to isolate workers from toxic off gas. The gas isolation barrier can be a bulkhead with one or more openings each sealed by a remotely removable seal, such as a flexible membrane, or a plate that can be remotely removed or opened to unseal such a bulkhead opening.

Abstract: A non-subsidence method for developing an in situ oil shale retort tract in a subterranean formation containing oil shale includes forming a number of spaced apart rows of in situ oil shale retorts, leaving intervening zones of unfragmented formation between adjacent rows of retorts for supporting the overburden loads without substantial subsidence. Each retort contains a fragmented permeable mass of formation particles containing oil shale. The retorts in each row are separated by gas barriers that provide support for the overburden load above each row of retorts. After retorting, a stabilizing material is introduced into the void spaces in the spent in situ oil shale retorts for increasing the compressive strength of the fragmented masses of spent oil shale particles in the spent in situ retorts. Thereafter, separate rows of in situ oil shale retorts are formed in corresponding intervening zones of unfragmented formation.

Abstract: The method of thermal-mine working of an oil reservoir includes providing at least one injection gallery and a recovery gallery and drilling therefrom, respectively, injection and recovery wells. The formation is heated up by feeding a heat carrier into the injection wells, and oil with associated water thus evolved is withdrawn through the recovery wells. The associated water is separated from the oil and pumped into the oil-bearing formation, to assist in driving-out the oil. The recovered oil is conveyed to the ground surface through the mine workings. At least one auxiliary well is also drilled, to connect directly the recovery gallery and the injection gallery; and, a pipe line is mounted in this auxiliary well and spaced from the walls of the bore of the auxiliary well. Oil and associated water are separated directly within the recovery gallery.

Abstract: An in situ oil shale retort is formed in a subterranean formation containing oil shale, a horizontally extending void is excavated within the boundaries of the retort site leaving a zone of unfragmented formation above and/or below such a void. A crack is propagated in at least one of the zones of unfragmented formation along the side boundaries of the retort site and thereafter the zone of unfragmented formation is explosively expanded towards such a void for forming a fragmented permeable mass of formation particles in the retort. Such a fragmented permeable mass is retorted in situ to produce shale oil.

Abstract: In-situ retorting methods include forming an in-situ mass of rubblized, hydrocarbon-containing minerals covering at least part of that mass with a nonflammable liquid such as water, uncovering part of the mass and retorting to produce hydrocarbon values from that part, and then progressively or sequentially uncovering other parts of the mass and retorting hydrocarbons from those parts. Methods for forming highly permeable rubblized masses include forming a retorting zone in a kerogen-bearing formation wherein two walls of the retorting zone form a low angle to one another, and cleaving oil shale from the upper wall beginning near the intersection of the two walls and proceeding upwardly.

Abstract: A method for forming a fragmented permeable mass of formation particles in an in situ oil shale retort is provided. A horizontally extending void is excavated in unfragmented formation containing oil shale and a zone of unfragmented formation is left adjacent the void. An array of explosive charges is formed in the zone of unfragmented formation. The array of explosive charges comprises rows of central explosive charges surrounded by a band of outer explosive charges which are adjacent side boundaries of the retort being formed. The powder factor of each outer explosive charge is made about equal to the powder factor of each central explosive charge. The explosive charges are detonated for explosively expanding the zone of unfragmented formation toward the void for forming the fragmented permeable mass of formation particles having a reasonably uniformly distributed void fraction in the in situ oil shale retort.

Abstract: A method for forming an in situ oil shale retort in a subterranean formation containing oil shale is provided. The in situ oil shale retort has a top boundary, generally vertically extending side boundaries, and a bottom boundary of unfragmented formation. A first portion of formation is excavated for forming at least one void within the boundaries, leaving a remaining portion of formation within the boundaries adjacent the void or voids. A remaining portion of unfragmented formation within the retort boundaries is explosively expanded toward such a void for forming a fragmented permeable mass of formation particles containing oil shale in the retort. A void space remains between the upper surface of the fragmented mass and overlying unfragmented formation. A lower portion of the overlying formation is explosively expanded downwardly toward the void space for substantially filling the retort with formation particles.

Abstract: A method is provided for flattening a non-planar combustion zone which is advancing through a fragmented permeable mass of formation particles in an in situ oil shale retort. To effect flattening of the non-planar combustion zone, a fragmented permeable mass of formation particles having generally horizontally extending layers of various void fraction is provided in the in situ retort. At least one layer has a substantially higher effective average void fraction than adjacent layers above and below this layer. When the advancing non-planar combustion zone enters the high void fraction layer, it spreads laterally across the layer. The resulting combustion zone is approximately flat in a plane transverse to its direction of advance when it exits the high void fraction layer.

Abstract: An in situ oil shale retort is formed within a subterranean formation containing oil shale. The retort contains a fragmented permeable mass of formation particles containing oil shale. A production level drift extends below the fragmented mass, leaving a lower sill pillar of unfragmented formation between the production level drift and the fragmented mass. During retorting operations, liquid and gaseous products are recovered from a lower portion of the fragmented mass. A liquid outlet line extends from a lower portion of the fragmented mass through the lower sill pillar for conducting liquid products to a sump in the production level drift. Gaseous products are withdrawn from the fragmented mass through a plurality of gas outlet lines distributed across a horizontal cross-section of a lower portion of the fragmented mass. The gas outlet lines extend from the fragmented mass through the lower sill pillar and into the production level drift.

Abstract: A fragmented permeable mass of formation particles is formed in an in situ oil shale retort in a subterranean formation containing oil shale. Formation is excavated to form a horizontally extending void in the subterranean formation and a support pillar of unfragmented formation is left in the void for supporting overlying unfragmented formation. The support pillar is prepared for explosive expansion by forming an array of explosive charges along the centerline of the pillar between its opposed free faces. The amount of explosive on each side of the centerline is about equal. Explosive is then detonated in the support pillar for expanding the pillar about equally toward both opposed free faces. Thereafter, explosive is detonated in unfragmented formation above and/or below the void for explosively expanding the formation toward the void to form the fragmented permeable mass of formation particles.

Abstract: A subterranean formation containing oil shale is prepared for in situ retorting by initially excavating a lower level drift adjacent a lower portion of an in situ oil shale retort site and excavating an air level void above the retort site. An undercut is excavated below a zone of unfragmented formation remaining within the retort site above the lower drift. The undercut tapers downwardly and inwardly to an opening in the lower drift for forming a draw point for withdrawing fragmented formation particles from the retort site. Formation within the remaining zone of unfragmented formation is explosively expanded downwardly in lifts for forming a fragmented permeable mass of formation particles containing oil shale within the retort site. A plurality of vertical blasting holes drilled in the remaining zone of unfragmented formation are loaded with explosive from the air level void prior to blasting each lift.

Abstract: A subterranean formation containing oil shale is prepared for in situ retorting by initially excavating a void in a lower portion of a retort site. A primary sub-round of explosive is placed in a portion of formation within the retort site above the void, and a secondary sub-round of explosive is also placed in unfragmented formation above the void. In one embodiment, the primary sub-round comprises explosive placed in separate pairs of longitudinally spaced apart upwardly converging blasting holes. Explosive in the primary sub-round is detonated for fracturing unfragmented formation along a boundary defined by the upwardly converging blasting holes to separate a portion of formation from adjacent unfragmented formation for forming at least one new face above the separated portion of formation.

Abstract: A subterranean formation containing oil shale is prepared for in situ retorting by initially excavating a plurality of vertically spaced apart voids within a retort site, leaving an intervening zone of unfragmented formation between an adjacent pair of such voids. The intervening zone has substantially parallel upper and lower horizontal free faces adjoining the voids. At least one pancake-shaped load of explosive is placed in the intervening zone. The pancake-shaped explosive load has faces which are substantially parallel to the upper and lower free faces, and the length of the axis of the explosive load is less than the radius of the load. The explosive load is detonated for explosively expanding formation toward the upper and lower free faces for forming an in situ retort containing a fragmented permeable mass of formation particles.

Abstract: An in situ oil shale retort in a subterranean formation contains a fragmented permeable mass of formation particles. Such a fragmented mass is formed by excavating a horizontally extending void within the boundaries of the retort, leaving a zone of unfragmented formation above and/or below such a void. A plurality of vertical blasting holes are drilled in such a zone and loaded with explosive charges for forming an array of explosive charges sufficiently close together to interact and fragment formation substantially to a plane at the ends of the charges remote from the void. The scaled depth of burial of such an array is in the range of from about 6 to 12 mm/cal.sup.1/3. The explosive charges are detonated in a single round for expanding such a zone towards the void for forming the fragmented mass of particles in the retort.

Abstract: There is provided a method of forming an in situ oil shale retort in a retort site within a subterranean formation containing oil shale. The in situ oil shale retort contains a fragmented permeable mass of formation particles. A first portion of formation is excavated from within the boundaries of the retort being formed to form at least one void. The surface of the formation defining such a void provides at least one free face extending through the formation. The second portion of formation is left within the boundaries of the retort being formed to be explosively expanded toward the void.At least two arrays of explosive charges are formed in the second portion of formation wherein the first array of explosive charges has a first burden distance and the second array of explosive charges has a second burden distance wherein the second burden distance is less than the first burden distance.

Abstract: An in situ oil shale retort is formed in a subterranean formation wherein the oil shale retort contains a fragmented permeable mass of formation particles containing oil shale. A limited void is formed in the subterranean formation and zones of unfragmented formation are left above and below the void and are loaded with explosive for explosively expanding unfragmented formation toward the void. The explosive is placed into the zones of unfragmented formation for forming a substantially horizontal array of main explosive charges and at least one substantially horizontal array of satellite explosive charges. Each of the satellite explosive charges has a scaled point charge depth of burial substantially equal to the scaled point charge depth of burial of each of the main explosive charges and the actual depth of burial of each of the satellite explosive charges is less than the actual depth of burial of each of the main explosive charges.

Abstract: An in situ oil shale retort is formed in a subterranean formation by excavating voids adjacent the top and bottom boundaries of the retort, leaving an intermediate zone of unfragmented formation between the voids. The lower level void is substantially larger than the upper level void. A lower portion of the intermediate zone is explosively expanded downwardly towards the lower level void for forming a first moiety of a fragmented mass of formation particles in the retort and leaving a void spaace over the top of the first moiety having about the same volume as the upper level void. Thereafter an upper portion of the intermediate zone is explosively expanded upwardly towards the upper level void and downwardly towards the void space for forming a second moiety of the fragmented mass in the retort. The fragmented mass has an average void fraction up to about 25% and no substantial part has a void fraction less than about 20%.

Abstract: A process for the preparation of grout from burned shale by treating the burned shale in steam at approximately 700.degree. C. to maximize the production of the materials alite and larnite. Oil shale removed to the surface during the preparation of an in-situ retort is first retorted on the surface and then the carbon is burned off, leaving burned shale. The burned shale is treated in steam at approximately 700.degree. C. for about 70 minutes. The treated shale is then ground and mixed with water to produce a grout which is pumped into an abandoned, processed in-situ retort, flowing into the void spaces and then bonding up to form a rigid, solidified mass which prevents surface subsidence and leaching of the spent shale by ground water.

Abstract: A gas seal is provided in an access drift excavated in a subterranean formation containing oil shale. The access drift is adjacent an in situ oil shale retort and is in gas communication with the fragmented permeable mass of formation particles containing oil shale formed in the in situ oil shale retort. The mass of formation particles extends into the access drift, forming a rubble pile of formation particles having a face approximately at the angle of repose of fragmented formation.The gas seal includes a temperature barrier which includes a layer of heat insulating material disposed on the face of the rubble pile of formation particles and additionally includes a gas barrier. The gas barrier is a gas-tight bulkhead installed across the access drift at a location in the access drift spaced apart from the temperature barrier.

Abstract: Disclosed is a method for reducing the porosity of a zone within mass of unretorted rubblized oil shale comprising locating the zone; providing fluid communication to the zone; introducing grout slurry by fluid communication to the zone so as to deposit slurry and reduce porosity. Also disclosed is an improved method for the subterranean in situ retorting of oil shale comprising establishing a retorting zone containing a rubblized mass comprising oil shale; establishing an essentially planar flame front within the retorting zone; introducing oxygen containing gas into the retorting zone to support combustion at the flame front thereby forming hot combustion gases which effect retorting of the oil shale; locating an area of the flame front which advanced ahead of the essentially planar flame front; and introducing grout slurry to the advanced area to reduce gas permeability and retard further advancement of that area of the flame front.

Abstract: Mineable coal seams which are in proximity to an overlying or underlying coal seam are degasified in advance of and during mining by drilling a generally horizontal borehole in the overlying or underlying coal seam and producing gas therefrom.

Abstract: An in situ oil shale retort is formed in a subterranean formation containing oil shale. The retort contains a fragmented permeable mass of formation particles containing oil shale and has a production level drift in communication with a lower portion of the fragmented mass for withdrawing liquid and gaseous products of retorting during retorting of oil shale in the fragmented mass. The principal portion of the fragmented mass is spaced vertically above a lower production level portion having a generally T-shaped vertical cross section. The lower portion of the fragmented mass has a horizontal cross sectional area smaller than the horizontal cross sectional area of the upper principal portion of the fragmented mass above the production level.

Abstract: A method for the in situ separation of viscous crude oil from a reservoir such as, oil sand, or tar sand is disclosed. Hot water is introduced to the top surface of the reservoir while steam is injected into the reservoir through drill holes. The hot water and steam may contain a surfactant. The bouyancy of the crude oil creates an artificial water drive which causes the water and oil to "flip-flop" so that the oil rises to the top of the reservoir and separates from the remainder of the reservoir material. If the overburden is deep, underground mining techniques may be used to reach the reservoir prior to applying the present method.

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.

Abstract: Normally immobile mineral values are recovered from a subterranean formation by penetrating the formation with an access shaft and drilling two radial arrays of substantially horizontal wells out into the formation from the shaft, one array of wells being substantially shorter than the other array. A mobilizing fluid is injected into the formation via alternate longer wells so that an outer zone of high fluid mobility is created in the formation. Then the mobilizing fluid is injected into all of the longer wells to sweep the mineral values to the shorter wells where such values are recovered. Improved sweep efficiency of the mineral values is achieved thereby.

Abstract: An in situ oil shale retort is formed in a subterranean formation containing oil shale. Formation is excavated from within a retort site for forming a plurality of vertically spaced apart voids extending horizontally across different levels of the retort site, leaving a separate zone of unfragmented formation between each pair of adjacent voids, and leaving one or more pillars within each void for providing temporary roof support for unfragmented formation above each void. A plurality of horizontally spaced apart vertical blast holes are drilled in each zone of unfragmented formation below the voids. A pillar within a first void is offset horizontally from at least a portion of a pillar in a second void excavated directly below the first void. This provides an access region in the first void above at least a portion of the pillar in the second void so that vertical blast holes can be drilled into a zone of unfragmented formation below the pillar in the second void from the access region in the first void.

Abstract: An insulated bulkhead seals an access drift adjacent a hot portion of a fragmented permeable mass of formation particles containing oil shale in an in situ oil shale retort. The bulkhead includes a steel plate for closing the cross-sectional area of the drift. The periphery of the bulkhead is anchored in concrete in a slot cut into the walls, roof and floor of the drift. A first layer of heat insulating material is applied to a face of the bulkhead plate adjacent the hot portion of the fragmented mass for reducing heat transfer to the bulkhead from the fragmented mass. A second layer of heat insulating material covers the walls, roof and floor of the drift adjacent the insulated face of the bulkhead plate to minimize thermal degradation of formation surrounding the periphery of the bulkhead.

Abstract: An in situ oil shale retort is formed in a subterranean formation containing oil shale, a horizontally extending void is excavated within the boundaries of the retort site leaving a zone of unfragmented formation above and/or below such a void, at least one pillar of unfragmented formation is left within the side boundaries of such a void for providing temporary support for overburden above the void, such a pillar is explosively expanded so that a principal portion of the pillar fragments travel to the side boundaries of the void and such a zone of unfragmented formation is explosively expanded toward the void. Accumulation of sufficient pillar fragments adjacent the side boundaries of the retort can substantially offset a tendency for fragments of the expanded zone of formation to form a mound thereby forming a fragmented permeable mass of formation particles within the retort with a reasonably flat upper surface. Such a fragmented permeable mass is retorted in situ to produce shale oil.

Abstract: The present invention comprises a method of mining a solid substance, such as coal, minerals, or the like, from an underground deposit in one of a plurality of earth strata. Void areas are created in the deposit so as to generally define an area within the deposit which is to be enclosed. Plugging material is injected into the void areas to form a relatively impervious barrier enclosing the aforementioned area of the deposit and isolating it from the remainder of the earth strata in which it is located. Conversion media, such as solvents or oxidation supporting media, are then injected into the enclosed area to convert the substance therein into flowable form. Finally, the substance as so converted is withdrawn from the enclosed area.

Abstract: A method for the in situ processing of mineral-bearing oil shale ore includes the establishment of a plurality of underground stopes by removing from each a portion of the oil shale ore therein, rubblizing the remaining ore in each stope, extracting the rubblized ore and crushing it to obtain a nahcolite fraction and an oil shale fraction having a desired particle size for subsequent processing, and restoring sized oil shale particles to the stope by back filling the stope as the rubble is extracted so as to maintain the stope substantially filled with particles to provide lateral support to the side walls and reduce the likelihood of caving in the stope. The nahcolite fraction is recovered from the crushed ore prior to backfilling of the stopes for retorting to recover shale oil, while soda ash and alumina may be recovered from the spent shale by leaching the stopes after retorting.

Abstract: An underground method for in situ leaching of mineral resource bodies is used to recover the mineral. The method comprises running a drift close to the resource body in such a manner as to minimize any effect on subsurface water; drilling long holes from the drift into the resource body at intervals which are determined by the character of the resource body; perforating the long holes and capping the long holes at the drift end with valves; injecting a recovery solution into a portion of the long holes and recovering the recovery solution from another portion of the long holes. The entire development of the drifts and long holes and the conduction of the recovery solution are done in such a manner as to minimize any effect on the subsurface water table or hydrostatic pressure. The spacing of the long holes is selected so as to maximize the exposure of the resource body to the recovery solution.

Abstract: A thermal-mining method of oil production is effected by digging a combination of underground workings and at least one working tunnel and by drilling injection and producing wells from said working tunnel. Then a heat carrier is forced into the oil-bearing bed for heating it to a temperature sufficient for the oil to acquire the necessary fluidity. The heat carrier is forced into the oil-bearing bed through injection wells at time intervals t.sub.1 found from an appropriate relation. The oil is withdrawn from the oil-bearing bed through the producing wells at time intervals t.sub.3 in which the time interval t.sub.1 of heat carrier injection into the injection wells is divisible by the time interval t.sub.3 of oil withdrawal from the producing wells, the multiplicity factor being equal to n=(t.sub.1 /t.sub.3).gtoreq.60.

Abstract: There is provided a method for forming an in situ oil shale retort in a subterranean formation containing oil shale. At least one void is excavated in the formation, leaving zones of unfragmented formation adjacent the void. An array of main blastholes is formed in the zone of unfragmented formation and at least one explosive charge which is shaped for forming a high velocity gas jet is placed into a main blasthole with the axis of the gas jet extending transverse to the blasthole. The shaped charge is detonated for forming an auxiliary blasthole in the unfragmented formation adjacent a side wall of the main blasthole. The auxiliary blasthole extends laterally away from the main blasthole. Explosive is placed into the main blasthole and into the auxiliary blasthole and is detonated for explosively expanding formation towards the free face for forming a fragmented permeable mass of formation particles in the in situ oil shale retort.

Abstract: A subterranean formation containing oil shale is prepared for in situ retorting by forming a fragmented permeable mass of formation particles containing oil shale in an in situ oil shale retort site. Formation is initially excavated from the retort site for forming one or more voids extending horizontally across the retort site, leaving a zone of unfragmented formation adjacent such a void. In one ambodiment, an array of rocks bolts are anchored in at least a portion of the roof adjacent such a void for providing reinforcement of unfragmented formation above the void. Vertical blasting holes are drilled in the zone of unfragmented formation adjacent the void. Explosive is placed in the blasting holes and detonated for explosively expanding the zone of unfragmented formation toward the void, including the rock bolted portion of the roof, for forming at least a portion of a fragmented permeable mass of formation particles containing oil shale in an in situ oil shale retort.

Abstract: An in situ oil shale retort is formed in a subterranean formation containing oil shale. A void can be formed in formation within the retort site by directing fluid under pressure against a zone of relatively weakened formation, such as tuffs, gravel beds, or fractured oil shale, to erode such weakened formation into particle form, leaving a void space adjacent a remaining zone of unfragmented formation within the retort site. The void space can be formed by drilling a bore hole into the zone of weakened formation, placing a jet nozzle in the bore hole, and forcing a fluid such as water through the nozzle against the weakened formation for eroding it to form the void space. Eroded formation particles are passed to the bottom of the bore hole. Such water jetting techniques can be used to form voids in zones of weakened formation interspersed throughout the retort site.

Abstract: A processing zone advances through a fragmented permeable mass of particles containing oil shale in an in situ oil shale retort in a subterranean formation containing oil shale. The retort has an effluent gas passing therefrom. The effluent gas has a heating value which is dependent on the kerogen content of the oil shale then in contact with the processing zone. To determine the locus of the processing zone, the formation is assayed at selected locations in the retort for kerogen content before processing the selected locations, and effluent gas from the retort is monitored for its heating value.

Abstract: An array of in situ oil shale retorts is formed in a development region in a subterranean formation containing oil shale. At least one void is excavated in each retort site, and remaining formation within each retort site is explosively expanded toward the void for forming a fragmented permeable mass of formation particles containing oil shale in each in situ retort. Overburden loads over an area of the development region are carried largely by the fragmented masses and partly by unfragmented partitions between retorts. Subsidence of overburden following explosive expansion is controlled at the boundary of the development region to avoid an abrupt change in the overburden load supported largely by the fragmented masses inside the boundary and the overburden load supported by unfragmented formation outside the boundary.

Abstract: A method for preparing a shale oil deposit for in situ retorting includes providing a drilling and process control level above the deposit with a substantial thickness of personnel isolating and protecting formation between the deposit and the level, providing a collecting and pumping level below the deposit with a substantial thickness of personel isolating and protecting formation between that level and the deposit, and excavation providing voids affording fragmentation of shale in the retorting zones reached from the collecting level. The shale excavated to provide the voids is transported through access risers to the collecting level; closures serving as sumps and protective gratings for the sumps are installed in the upper ends of the risers. Introduction of combustion gases from the control level is accomplished through drill holes provided for this purpose, some of the drill holes also being provided with control or detecting devices.

Abstract: A fragmented recovery zone in a subterranean ore seam has a polygonal cross section with a low void volume and a conical funnel-shaped bottom with a high void volume. Recovered constituents are removed from the recovery zone at the point of convergence of the funnel.

Abstract: An in situ oil shale retort is formed in a subterranean oil shale deposit by excavating a columnar void having a vertically extending free face, drilling blasting holes adjacent to the columnar void, loading the blasting holes with explosive, and detonating the explosive in a single round to expand the shale adjacent to the columnar void toward the free face to fill with fragmented oil shale the columnar void and the space in the in situ retort originally occupied by the expanded shale prior to the expansion. A room having a horizontal floor plan that coincides approximately with the horizontal cross section of the retort to be formed is excavated so as to intersect the columnar void. The room can lie above the columnar void, below the columnar void, or intermediate the ends of the columnar void. The expanded or fragmented shale has a low average void volume. The void volume of the fragmented shale increases at the bottom of the in situ retort.

Abstract: In situ shale oil recovery from oil shale deposits using radio frequency energy as a heat generator is facilitated by rubblizing the shale oil deposits before application of radio frequency energy.

Abstract: The method of thermal-mine oil production includes provision of a system of mine workings and at least one operation gallery, drilling production wells from the gallery into the upper and lower portions of the oil-bearing bed, drilling from the gallery injection wells into the central portion of the oil-bearing bed, positively injecting a heat carrier through said injection and production wells into the oil bearing bed to heat the latter to a temperature at which the oil attains the required fluidity within the oil bearing bed, positively feeding a heat carrier via the injection wells into the central portion of the oil-bearing bed for uniform distribution of the heat carrier throughout the body of the oil-bearing bed and forcing oil therefrom into the said production wells.

Abstract: Apparatus for the in-situ retorting of carbonaceous deposits includes a plurality of retorts connected to a common exhaust tunnel effectively free of broken shale into which products of the retorting are discharged. To allow simultaneous mining, rubblization and retorting of the in-situ retorts, the exhaust tunnel is provided with doorways between the retorts. Doors movable in the exhaust tunnel are adapted to seal against the doorways to prevent flow from retorts in which retorting is in progress to retorts under construction. A trench in the exhaust tunnel is provided for flow of liquid products produced in the retorting. A liquid seal under the doorways communicates with the trench to provide a passage for liquid flow past the doorways and to prevent upstream flow of gaseous products through the passage for the liquid flow.