Claims
- 1. The method of recovering oil from oil shale in situ comprising: mining a first tunnel substantially horizontally in a subterranean formation containing oil shale, mining a chamber in the formation extending above the tunnel, blasting formation adjacent the chamber to form a cavity in the formation filled with a fragmented permeable mass of formation particles containing oil shale, igniting oil shale at an intermediate level between the top and the bottom of the cavity, introducing an oxygen containing gas at the intermediate level to sustain combustion of the oil shale and for retorting oil shale between the intermediate level and the bottom of the cavity, thereby leaving uncombusted oil shale in the cavity between the intermediate level and the top of the cavity, and withdrawing gases from the bottom of the cavity.
- 2. The method of claim 1 further comprising mining a second tunnel into the side of the cavity at said intermediate level, the oxygen containing gas being introduced through said tunnel.
- 3. A method for recovering values from an in situ oil shale retort in a subterranean formation containing oil shale, the in situ retort containing a fragmented premeable mass of formation particles containing oil shale, the fragmented mass having side boundaries, a first end boundary, and a second end boundary, the method comprising the steps of:
- passing a measuring gas through at least a portion of the fragmented mass between the first end boundary of the fragmented mass and the second end boundary of the fragmented mass;
- measuring the unit pressure drop of said measuring gas in a first portion of the fragmented mass between the first end boundary of the fragmented mass and an intermediate location, the intermediate location being between the first end boundary and the second end boundary of the fragmented mass, and also measuring the unit pressure drop of said measuring gas in a second portion of the fragmented mass between the intermediate location and the second end boundary of the fragmented mass to determine if the unit pressure drop of said measuring gas is substantially greater in the first portion than in the second portion;
- if the unit pressure drop of said measuring gas is substantially greater in the first portion of the fragmented mass than in the second portion of the fragmented mass, introducing a processing gas to the retort at an intermediate location between the first portion of the fragmented mass and the second end boundary of the fragmented mass for processing oil shale in the retort in the second portion of the fragmented mass, thereby leaving unprocessed oil shale in the first portion of the fragmented mass; and
- withdrawing gas from the retort from the second end boundary of the fragmented mass.
- 4. The method of claim 4 comprising the additional step of mining a drift into fluid communication with the fragmented mass in the retort at the intermediate location at which a processing gas is introduced to the retort, and wherein the step of introducing a processing gas comprises introducing an oxygen containing gas to the retort through the drift.
- 5. The method of claim 4 wherein the first end boundary of the fragmented mass is the bottom of the retort and the second end boundary of the fragmented mass is the top of the retort.
- 6. The method of claim 6 wherein processing gas is introduced to the retort at an intermediate location between the top and the bottom of the retort.
- 7. The method of claim 6 wherein the first and second end boundaries are spaced apart from each other a greater distance than opposing side boundaries are spaced apart from each other.
- 8. The method of claim 4 wherein the processing gas contains oxygen.
- 9. The method of claim 4 wherein the first end boundary of the fragmented mass is the top of the retort and the second end boundary of the fragmented mass is the bottom of the retort.
- 10. The method of claim 10 wherein processing gas is introduced to the retort at an intermediate location between the top and the bottom of the retort.
- 11. The method of claim 10 wherein the first and second end boundaries are spaced apart from each other a greater distance than opposing side boundaries are spaced apart from each other.
- 12. A method for recovering liquid and gaseous products from an in situ oil shale retort in a subterranean formation containing oil shale, the in situ retort containing a fragmented permeable mass of formation particles having side boundaries, a top boundary, and a bottom boundary, the method comprising the steps of:
- passing a measuring gas through the fragmented mass between the top boundary of the fragmented mass and the bottom boundary of the fragmented mass;
- measuring the unit pressure drop of said measuring gas in an upper portion of the fragmented mass between the top boundary and an intermediate level between the top boundary and the bottom boundary of the fragmented mass, and also measuring the unit pressure drop of the measuring gas in a lower portion of the fragmented mass between the intermediate level and the bottom end boundary of the fragmented mass to determine if the unit pressure drop of said measuring gas is substantially greater in the upper portion of the fragmented mass than in the lower portion of the fragmented mass;
- if the unit pressure drop of said measuring gas is substantially greater in the upper portion of the fragmented mass than in the lower portion of the fragmented mass, introducing a processing gas to the retort at the intermediate level for processing oil shale in the retort in the lower portion of the fragmented mass, thereby leaving unprocessed oil shale in the upper portion of the fragmented mass; and
- withdrawing liquid products and off gas including gaseous products from the retort from the bottom boundary of the fragmented mass.
- 13. The method of claim 13 comprising the additional step of establishing a combustion zone in the retort at the intermediate level before introducing a processing gas, and wherein the step of introducing a processing gas comprises introducing an oxygen containing gas to the retort at the intermediate level to advance the combustion zone toward the bottom of the retort.
- 14. In a method of recovering gaseous products from an in situ oil shale retort in a subterranean formation containing oil shale, the in situ retort containing a fragmented permeable mass of particles containing oil shale and having a combustion zone and a retorting zone advancing therethrough, the fragmented mass having side boundaries, a first end boundary, and a second end boundary, wherein the method comprises the steps of:
- introducing into the in situ oil shale retort on the trailing side of the combustion zone an oxygen containing gas to advance the combustion zone through the fragmented mass of particles and produce combustion gas in the combustion zone;
- passing combustion gas and any unreacted portion of the oxygen containing gas through a retorting zone in the fragmented mass of particles on the advancing side of the combustion zone, wherein oil shale is retorted and gaseous products are produced;
- withdrawing a retort off gas comprising said gaseous products, combustion gas and any gaseous unreacted portions of the oxygen containing gas from the in situ oil shale retort from the advancing side of the retorting zone;
- the improvement comprising the steps of:
- (i) passing a measuring gas through at least a portion of the fragmented mass between the first end boundary of the fragmented mass and the second end boundary of the fragmented mass before introducing the oxygen containing gas into the retort;
- (ii) measuring the unit pressure drop of said measuring gas in a first portion of the fragmented mass between the first end boundary of the fragmented mass and an intermediate location, the intermediate location being between the first end boundary and the second end boundary of the fragmented mass, and also measuring the unit pressure drop of said measuring gas in a second portion of the fragmented mass between the intermediate location and the second end boundary of the fragmented mass to determine if the unit pressure drop of said measuring gas is substantially greater in the first portion than in the second portion;
- (iii) if the unit pressure drop of said measuring gas is substantially greater in the first portion of the fragmented mass than in the second portion of the fragmented mass, introducing the oxygen containing gas to the retort at an intermediate location between the first portion of the fragmented mass and the second end boundary of the fragmented mass for processing oil shale in the retort in the second portion of the fragmented mass, thereby leaving unprocessed oil shale in the first portion of the fragmented mass; and
- (iv) withdrawing off gas from the retort from the second end boundary of the fragmented mass.
- 15. The method of claim 15 comprising the additional step of mining a drift into the retort at the intermediate location at which the oxygen containing gas is introduced to the retort.
- 16. The method of claim 15 wherein the first end boundary of the fragmented mass is the top of the retort and the second end boundary of the fragmented mass is the bottom of the retort.
CROSS-REFERENCES
This application is a continuation-in-part of copending application Ser. No. 737,154 filed on Oct. 29, 1976, now abandoned, the subject matter of which is incorporated herein by reference and which is a continuation of patent application Ser. No. 683,037 filed on May 4, 1976, now abandoned, which is a continuation of patent application Ser. No. 615,043, filed on Sept. 19, 1975, now abandoned, which is a continuation of application Ser. No. 492,768 filed on July 29, 1974, now abandoned.
US Referenced Citations (12)
Continuations (3)
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Number |
Date |
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683037 |
May 1976 |
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Parent |
615043 |
Sep 1975 |
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Parent |
492768 |
Jul 1974 |
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Continuation in Parts (1)
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Number |
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737154 |
Oct 1976 |
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