Patent US3616855A successfully refreshed from Google Patents.
US3616855A
Expired / Lapsed
US
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Method of bulking or caving a volume of subsurface material
Assignee: New Mexico Tech Research Foundation
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Filing: 1970-07-23
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Granted: 1971-11-02
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Expires: 1990-07-23
Abstract
Abstract A volume of subsurface material is bulked or caved by generating a gas pressure in the base of the volume in a time of from about 1 to about 10 seconds having an energy input sufficient to lift the overburden material to an extent such that material falls or caves and leaves a chamber having a generally hemispherical roof containing the caved material and providing an interconnected void space. The gas pressure to obtain what may be termed a quasi-static lifting of the overburden material may be generated by shock ignition of a volume-burning propellant, by flame front ignition of a volume-burning propellant, by combustion of an oxidizer and fuel delivered separately and mixed in place in the base of the volume, or by rapid delivery to the base of the volume of a previously stored gas under high pressure.
Inventors
- 👤 Stirling A Colgate
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 11:22
CPC Classifications
E; E21; E21B; E21B43/00; E21B43/25; E21B43/26; E21B43/263; E21B43/16; E21B43/24
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
35 words
A method according to claim 1 wherein the fuel-oxidizer mixture constitutes a volume-burning propellant and is gasified by propagating through it a weak detonation front or strong shock to provide shock ignition and secondary burn.
Claim 2
Dependent Claim
36 words
A method according to claim 1 wherein the fuel-oxidizer mixture is a fluid and is gasified by generating a rapidly progressing flame front and establishing Taylor unstable mixing to provide flame front ignition of the mixture.
Claim 3
Dependent Claim
41 words
A method according to claim 3 wherein the gas pressure is generated by introducing separately at the said base of the volume a fuel and an oxidizer for the fuel that oxidizes the fuel upon mixing therewith under the environmental conditions.
Claim 4
Independent Claim
109 words
A method of bulking or caving a volume of subsurface material comprising the steps of creating a generally horizontal fracture at the base of said volume, emplacing in the fracture a layer of a heterogeneous mixture of a fuel and an oxidizer for the fuel capable of relatively slow gasification, and igniting the mixture to generate by burning of the mixture a gas pressure in a time of from about 1 to about 10 seconds with sufficient energy to lift the overburden material above the fracture such that the overburden material falls or caves and leaves a generally hemispherical chamber containing caved material and providing an interconnected void space.
Claim 5
Dependent Claim
22 words
A method according to claim 5 wherein the fracturing and emplacement steps are carried out simultaneously by fracturing with the fuel-oxidizer mixture.
Claim 6
Dependent Claim
17 words
A method according to claim 5 wherein the fracturing is accomplished prior to emplacing the fuel-oxidizer mixture.
Claim 7
Dependent Claim
37 words
A method according to claim 7 wherein the material is first repeatedly fractured with a setting or partially setting and self-propping fracturing fluid to redistribute the stresses in the material and ensure a final substantially horizontal fracture.
Claim 8
Dependent Claim
38 words
A method according to claim 5 wherein the fuel-oxidizer mixture constitutes a volume-burning propellant and is gasified by propagating through it a weak detonatIon front or strong shock to permit shock ignition and secondary burn of the propellant.
Claim 9
Dependent Claim
34 words
A method according to claim 9 wherein the fuel is a fluid hydrocarbon, and the oxidizer is a member selected form the group consisting of ammonium perchlorate (NH4C103), potassium perchlorate (KC103), and combinations thereof.
Claim 10
Dependent Claim
27 words
A method according to claim 5 wherein the fuel-oxidizer mixture is a fluid and is gasified by generating a rapidly progressing flame front igniton of the mixture.
Claim 11
Independent Claim
55 words
A method of obtaining control and redistribution of stresses in a volume of underground material comprising the step of sequentially and repeatedly fracturing the material in said volume along at least two nonparallel fracture zones diverging generally upwardly and outwardly from a zone of a well bore with a setting or partially setting fracturing fluid.
Claim 12
Dependent Claim
14 words
A method according to claim 12 wherein the fracturing fluid is a setting cement.
Claim 13
Dependent Claim
16 words
A method according to claim 12 wherein the fracturing fluid is a self-propping and bridging mud.
Claim 14
Dependent Claim
18 words
A method according to claim 12 wherein the fracturing fluid is permitted to set after each fracture operation.
Claim 15
Independent Claim
110 words
A method of obtaining control and redistribution of stresses in a volume of underground material comprising the steps of repeatedly pumping into the volume from a point in a well bore passing through the volume a setting or partially setting fluid under a pressure sufficient to generate a fracture diverging generally upwardly and outwardly from the said point in the well bore, and allowing the fluid to set between each of the said repeated pumping steps, thereby successively to spread portions of the volume of material generally laterally to compress such portions and generate lateral stresses in the volume of material to render the material in the volume essentially self-supporting.
Claim 16
Dependent Claim
15 words
A method according to claim 16 wherein the fluid is a self-propping and bridging mud.
Claim 17
Dependent Claim
15 words
A method according to claim 16 wherein the fluid is a self-propping and bridging mud.
Claim 18
Dependent Claim
56 words
A method according to claim 16 wherein the total volume of fluid pumped into the volume of material by the repeated pumping steps is approximately equal to the volume of the said volume of material times one-third the ratio of the overburden pressure at said point in the well bore to Young''s Modulls for the material.
Claim 19
Dependent Claim
28 words
A method according to claim 16 and further comprising the step of mining underground strata below said volume of material after completing the repeated pumping and setting steps.
Claim 20
Dependent Claim
35 words
A method according to claim 16 and further comprising the step of pumping a fluid into the ground below said volume of material for storage thereof after completing the said repeated pumping and setting steps.
Claim 21
Dependent Claim
42 words
A method according to claim 16 and further comprising the step of forming a standard fluid fracture in a zone below said volume of material to facilitate recovery of fluid from said zone after completing the said repeated pumping and setting steps.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-11-01 | 1975-05-03 | 1975-11-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-11-01 | 1979-05-03 | 1979-11-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-11-01 | 1983-05-03 | 1983-11-02 | $7700.00 | Window Closed / Lapsed |