Occidental Oil Shale, Inc.

Occidental Petroleum

Richard D Ridley

Chang Y Cha

Robert S Burton, Iii

Gordon B French

Ned M Hutchins

William J Bartel

Robert J Fernandes

An in situ oil shale retort is formed in a subterranean formation containing oil shale and having horizontal cleavage planes extending parallel to the bedding of the formation and approximately orthogonal vertical cleavage plane sets extending perpendicular to the horizontal cleavage planes. The in situ retort is formed by excavating an opening or void in a retort site in the formation and placing explosive in the formation adjacent the void such that the explosive can fracture formation along the vertical cleavage planes and expand remaining formation within the retort site toward the void, forming a fragmented permeable mass of formation particles containing oil shale within the retort site.

In situ recovery of shale oil

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 is determined by monitoring in a well extending through unfragmented formation adjacent the retort, for condition in the retort affected by the advancement of such a processing zone through the retort. Monitoring can be effected by placing means for monitoring such a condition in such a well extending through unfragmented formation adjacent the retort.

Determining the locus of a processing zone in an in situ oil shale

A method for recovering liquid and gaseous products from an in situ oil shale retort in a subterranean formation containing oil shale is disclosed. The method is practiced on an in situ oil shale retort having a plurality of fragmented permeable masses of formation particles with an upper and at least one lower fragmented mass. A zone of unfragmented formation intervenes between such fragmented masses and has a plurality of vertically extending holes for distributing fluid from the fragmented mass above to the fragmented mass below the zone of unfragmented formation. A processing gas is introduced to the upper fragmented mass and an off gas is withdrawn from the lower fragmented mass establishing a retorting zone in the upper fragmented mass and advancing the retorting zone downwardly through the upper fragmented mass, through such holes in the zone of unfragmented formation, and into and through the lower fragmented mass. The oil shale within the fragmented masses is retorted producing liquid and gaseous products. The liquid products are recovered from the fragmented mass from which they are produced and the gaseous products are recovered from the off gas withdrawn from the lower fragmented mass.

In situ oil shale retort with intermediate gas control

An in situ oil shale retort is formed in a subterranean formation containing oil shale. Such an in situ oil shale retort contains a fragmented permeable mass of formation particles containing oil shale including a lower moiety and an upper moiety of said fragmented mass. The fragmented permeable mass of formation particles has top, bottom and side boundaries. A first portion of the formation is excavated from within the boundaries of the fragmented mass being formed to form a void. A second portion of the formation is excavated from within the boundaries of the fragmented mass being formed to form at least one additional void in communication with the first void and leaving a third portion to be expanded toward such an additional void. Fragmented particles from the excavation of such an additional void are deposited in the first void to provide a lower moiety of the fragmented permeable mass of formation particles. The third portion of the formation is explosively expanded toward such an additional void to provide an upper moiety of the fragmented permeable mass of formation particles. A retorting zone is passed through the upper and lower moieties of the fragmented mass for recovering liquid and gaseous products including shale oil.

Situ retort with high grade fragmented oil shale zone adjacent the lower

Oil shale formation is explosively expanded toward a limited void volume for forming an in situ oil shale retort in a subterranean formation containing oil shale. In one embodiment, a void in the form a narrow vertical slot is excavated within a retort site, leaving at least one portion of unfragmented formation within the retort site adjacent a vertical free face of the slot. Explosive is placed in a row of vertical blasting holes in the remaining portion of unfragmented formation adjacent the vertical free face. The blasting holes are mutually spaced apart along the length of the slot, and the row of blasting holes extends generally parallel to the vertical free face. Explosive in the blasting holes is detonated in a time delay sequence starting near one end of the slot and progressing along the length of the slot for explosively expanding formation in the remaining portion of unfragmented formation toward the vertical free face for forming a fragmented permeable mass of formation particles containing oil shale in an in situ oil shale retort.

Method of detonating explosives for fragmenting oil shale formation

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 formation comprises at least one stratum of relatively higher average kerogen content which is included in formation of relatively lower average kerogen content. A void is excavated in a retort site in the formation, leaving a remaining portion of unfragmented formation within the retort site adjacent the void. The portion of unfragmented formation within the retort site is explosively expanded toward the void to form a fragmented permeable mass of formation particles containing oil shale in an in situ retort in which fragmented formation particles from the stratum of higher kerogen content have a larger void fraction than the averge void fraction of the fragmented mass. This can be accomplished by enlarging the void in the vicinity of the stratum having the higher kerogen content prior to explosive expansion. When the fragmented mass is retorted, there is no substantial increase in resistance to flow of gas through the fragmented mass due to the relatively higher thermal expansion of fragmented formation particles having the higher kerogen content.

Method of forming an in situ oil shale retort with void volume as

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 from which to control retorting operations. A plurality of blasting holes used in explosively expanding the formation extend from the base of operation, through the sill pillar, and open into the top of the fragmented mass. Trenches are formed in the base of operation for collecting ground water which enters the base of operation prior to and during retorting operations, and collected ground water is withdrawn from the base of operation. Casings can be placed in the blasting holes and adapted for controlling gas flow through the fragmented mass during retorting operations. The casings extend above the floor of the base of operation to inhibit flow of ground water through the blasting holes into the fragmented mass, and other blasting holes not having such casings are sealed. After retorting is completed, the floor of the base of operation can be covered with a layer of concrete and/or the blasting holes can be sealed with concrete to inhibit leakage of ground water into treated oil shale particles in the fragmented mass.

Ground water control for 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 in the retort between the access drift and an elevation spaced below the bottom of the base of operation, leaving a horizontal sill pillar of intact formation between the top of the retort and the bottom of the base of operation. The sill pillar has a vertical thickness sufficient to maintain a safe base of operation above the retort after the fragmented mass is formed. Prior to retorting, a particulate combustible material is placed in the blasting holes and ignited, and air is introduced to the ignited particulate combustible material to generate heated ignition gas for heating an upper portion the fragmented mass below the sill pillar to a temperature greater than the spontaneous ignition temperature of carbonaceous materials in the oil shale. Heated organic carbonaceous material is then contacted with oxygen supplying gas to establish a combustion zone in the fragmented mass. The combustion zone is advanced downwardly through the fragmented mass to provide retorting of particles containing oil shale. Liquid and gaseous products of retorting are withdrawn from the fragmented mass.

Ignition of fragmented oil shale below a sill pillar in an in situ oil

Sulfur dioxide is removed from a process gas by passing the process gas through a first fragmented permeable mass of particles containing treated oil shale and including alkaline earth metal oxides at a sufficient temperature to remove sulfur dioxide from the process gas. Gas containing sulfur dioxide from the first fragmented mass is passed through a second fragmented permeable mass of particles containing treated oil shale and including alkaline earth metal oxides. Water in the second fragmented mass combines with alkaline earth metal oxides in the second fragmented mass and sulfur dioxide in the gas from the first fragmented mass with resultant removal of sulfur dioxide from gas from the first fragmented mass.

Two-stage removal of sulfur dioxide from process gas using treated oil

Sulfur dioxide is removed from a gas stream by passing the gas through retorted oil shale particles containing alkaline earth metal oxides.

Removing sulfur dioxide from gas streams with retorted oil shale

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.

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 at an elevation above the fragmented mass to be formed, and an access drift is excavated to provide access 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 then detonating explosive in such holes to form the fragmented mass of particles in the retort below the sill pillar. During retorting, gas is introduced into the fragmented mass through such blasting holes for establishing a combustion zone in the fragmented mass and for advancing the combustion zone through the fragmented mass. The blasting holes have separate valves located in the base of operation for use in controlling gas flow through selected regions of the fragmented mass.

Subterranean in situ oil shale retort and method for making and

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.

Method for preconditioning oil shale preliminary to explosive expansion

Sulfur dioxide is removed from a process gas by passing the process gas through a fragmented permeable mass of particles containing treated oil shale and including alkaline earth oxides. Water in the fragmented mass combines with alkaline earth oxides in the fragmented mass and sulfur dioxide in the process gas with resultant removal of sulfur dioxide from the process gas.

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Grand Junction, CO, United States of America

Richard D Ridley