Occidental Oil Shale, Inc.

Occidental Petroleum

Robert S Burton, Iii

Chang Y Cha

Richard D Ridley

William J Bartel

Carlon C Chambers

Thomas E Ricketts

Gordon B French

Sten I Rundberg

James V Vaughn

Carl C Chambers

Gregory C Benson

Robert F Hughes

Thomas P Williams

An in situ oil shale retort is formed in a subterranean formation containing oil shale by excavating one or more horizontally extending voids across a retort site, leaving a zone of unfragmented formation having a horizontal free face adjacent such a horizontal void. In one embodiment, such a horizontal void is excavated across less than the entire width of the retort site, leaving 'side pillars' of unfragmented formation spaced inwardly from adjacent side boundaries of the retort site at opposite sides of such a horizontal void. This reduces the maximum span of the horizontal void, when compared with supporting overburden above the void with one or more interior isolated pillars spaced inwardly from the side boundaries of the retort. The side pillars are explosively expanded. Then such a zone of unfragmented formation is explosively expanded toward such a horizontal void for forming a fragmented permeable mass of formation particles containing oil shale in the retort. The resulting fragmented mass can have a slightly narrowed region along the sides where the side pillars were present.

In situ oil shale retort having horizontal voids with side pillars

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.

Gas seal for an in situ oil shale retort and method of forming thermal

A technique is provided for igniting an in situ oil shale retort having an open void space over the top of a fragmented mass of particles in the retort. A conduit is extended into the void space through a hole in overlying unfragmented formation and has an open end above the top surface of the fragmented mass. A primary air pipe having an open end above the open end of the conduit and a liquid atomizing fuel nozzle in the primary air pipe above the open end of the primary air pipe are centered in the conduit. Fuel is introduced through the nozzle, primary air through the pipe, and secondary air is introduced through the conduit for vortical flow past the open end of the primary air pipe. The resultant fuel and air mixture is ignited for combustion within the conduit and the resultant heated ignition gas impinges on the fragmented mass for heating oil shale to an ignition temperature.

Method and apparatus for igniting an in situ oil shale retort

The locus of a processing zone advancing through a fragmented permeable mass of formation particles in an in situ oil shale retort in a subterranean formation containing oil shale and which generates an effluent fluid is determined by placing a halogen source in the permeable mass for providing an identifiable halogen and monitoring effluent fluid from the processing zone for presence of such halocarbon. The halogen source provides halogen at a predetermined temperature.

Method of doping retort with a halogen source to determine the locus of

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. During retorting, oxygen-supplying gas is introduced into an upper level of the fragmented mass for establishing a combustion zone and for advancing the combustion zone downwardly through the fragmented mass. Liquid and gaseous products, including shale oil and off gas, are withdrawn from a generally U-shaped production level drift at a lower level of the fragmented mass. Liquid in a lower portion of the U seals against the roof of the drift to provide a gas seal which inhibits passage of off gas from a first leg of the drift in communication with the retort to a second leg of the drift remote from the retort. A retaining wall in the second leg of the drift can provide lateral support for the liquid forming the gas seal, and help minimize the depth of excavation of the U-shaped drift. Shale oil and off gas can be separately withdrawn from the first leg of the drift.

Means for providing gas seal in production level drift for in situ oil

An in situ oil shale retort in which a cavity filled with broken particles of oil shale is formed within the subsurface oil shale formation and air is forced down through the cavity to sustain combustion of the top layer of oil shale particles, the products of combustion being withdrawn at the bottom of the cavity. A plurality of exhaust pipes traverse the bottom of the cavity and extend out through the sealed entrance to the retort cavity. The pipes are supported above the floor of the cavity and have holes opening on the bottom side of the pipes through which the product gases are withdrawn from the cavity. Valves in each pipe control the flow so as to balance the flow distribution of air and exhaust gases through the retorting cavity.

Gas collection system for oil shale retort

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. During retorting, oxygen-supplying gas is introduced into an upper level of the fragmented mass for establishing a combustion zone and for advancing the combustion zone through the fragmented mass. Liquid and gaseous products, including shale oil and off gas, are withdrawn from a sealed portion of a production level drift which extends laterally away from the lower level of the fragmented mass. A bulkhead sealed across the drift inhibits passage of off gas from behind the bulkhead to the portion of the drift on the side of the bulkhead opposite the fragmented mass. Off gas, shale oil and water are separately withdrawn from behind the bulkhead. A liquid level is maintained against the surface of the bulkhead facing the fragmented mass to seal the lower edge of the bulkhead and the drift floor adjacent the bulkhead against the passage of off gas through any rock fissures which can be present in the floor of the drift.

Liquid seal for production level bulkhead for in situ oil shale retort

An in situ fragmented permeable mass of particles containing treated oil shale is formed by excavating a void in a subterranean formation containing oil shale, explosively expanding formation toward such a void to form a fragmented permeable mass of formation particles containing oil shale, and retorting the particles containing oil shale in the fragmented mass. Water containing impurities is introduced into such an in situ fragmented permeable mass of particles containing treated oil shale, i.e., retorted or combusted oil shale or both, for disposal, purification, or generation of steam. The water introduced can be water containing hydrocarbons such as process water from retorting oil shale or water containing suspended solids such as blowdown from a steam generator. When the fragmented permeable mass is still hot from retorting, steam is generated which can be withdrawn for use in oil shale recovery operations. When the fragmented permeable mass does not contain particles at a high enough temperature for steam generation, water containing impurities can be purified by percolating it through the mass. A hot fragmented permeable mass can be used in turn for steam generation until it has cooled, then for removing impurities from water until it becomes too heavily contaminated, and finally for disposal of water containing impurities.

Water treatment and heating in spent shale oil retort

An apparatus is provided for determining the locus of a processing zone which advances through a fragmented permeable mass of particles in an in situ oil shale retort in a subterranean formation containing oil shale. The apparatus, which functions by releasing means for providing an indicator at a preselected temperature, comprises container means, means for providing an indicator in the container, and means for releasing the indicator providing means at a selected temperature greater than ambient.

Containers for indicators

An in situ oil shale retort containing a fragmented permeable mass of formation particles containing oil shale is formed in a subterranean formation. The void fraction of the fragmented mass is from about 10 to about 25 percent, and the weight average diameter of particles in the fragmented mass is from about 0.02 to about 0.3 foot. Combustion zone feed containing oxygen is introduced to a combustion zone established in the fragmented mass. The rate at which the combustion zone feed is introduced to the combustion zone is controlled for maintaining the modified Reynolds number of gas passing through the combustion zone in the range of from about 0.1 to about 20.

Operation of an in situ oil shale retort

The locus of a processing zone advancing through a fragmented permeable mass of particles in an in situ oil shale retort in a subterranean formation containing oil shale and which generates an effluent fluid is determined by placing an indicator source for providing an indicator, and monitoring effluent fluid from the processing zone for presence of indicator. The indicator source provides indicator at a predetermind temperature.

Doping a retort to determine the locus of a processing zone

Oil shale is pyrolyzed by introducing an oil shale feed to a retorting zone fluidized bed to yield, as products of retorting, retorted oil shale containing residual carbonaceous material and volatilized hydrocarbons. The retorted oil shale particles are passed to the top of a combustion zone fluidized bed into which a gaseous source of oxygen is introduced for fluidizing the combustion zone fluidized bed and oxidizing residual carbonaceous material contained in the retorted oil shale particles to yield combustion gases for fluidizing the retorting zone fluidized bed and for maintaining the retorting zone fluidized bed at a temperature sufficient to retort oil shale.

Fluidized bed process for retorting oil shale

A method for retorting oil shale in an in situ oil shale retort includes the steps of excavating a void in a subterranean formation containing oil shale and placing combustible material in the void adjacent an ignition situs. Formation is then explosively expanded toward the void to form a retort containing a fragmented permeable mass of formation particles containing oil shale, the top layer of the fragmented mass adjacent an ignition situs containing such combustible material. The combustible material is then ignited for establishing a combustion zone in the retort.

Method for establishing a combustion zone in an in situ oil shale retort

An in situ oil shale retort is formed in a subterranean formation containing oil shale. The retort contains a fragmented permeable mass of particles containing oil shale. An open base of operation is excavated in the formation above the retort site, and an access drift is excavated to the bottom of the retort site. Formation is explosively expanded to form the fragmented mass between the access drift and an elevation spaced below the bottom of the base of operation, leaving a horizontal sill pillar of unfragmented formation between the top of the fragmented mass and the bottom of the base of operation. The sill pillar provides a safe base of operation above the fragmented mass after it is formed. The fragmented mass is formed by, among other steps, drilling blasting holes from the base of operation down through the sill pillar and detonating explosive in the holes to form the fragmented mass of particles in the retort below the sill pillar. The fragmented mass is ignited through at least a first one of such blasting holes to establish a combustion zone in the top of the fragmented mass. The combustion zone is then advanced across the top of the fragmented mass by generating a gas pressure differential between the first blasting hole and at least a second blasting hole to draw gas down through the first blasting hole, across a top portion of the fragmented mass, and up through a second blasting hole so that gas flow across an upper portion of the fragmented mass spreads the combustion zone across the fragmented mass.

Establishing a combustion zone below a sill pillar in an in situ oil

The locus of a processing zone advancing through a fragmented permeable mass of particles in an in situ oil shale retort in a subterranean formation containing oil shale is determined by monitoring pressure in the retort. Monitoring can be effected by placing a pressure transducer in a well extending through the formation adjacent the retort and/or in the fragmented mass such as in a well extending into the fragmented mass.

Growing community of inventors

Grand Junction, CO, United States of America

Robert S Burton, Iii