US3917345A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Well stimulation for solution mining
Assignee: Kennecott Utah Copper LLC
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Filing: 1973-12-06
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Granted: 1975-11-04
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Expires: 1993-12-06
Abstract
Abstract Methods for increasing the permeability of a subterranean igneous rock formation penetrated by at least one well where a hydraulic fluid is injected into the formation at a pressure sufficient to cause diffusion into the natural fractures thereof and thus increase the cross-sectional area thereof, maintaining the pressure and injecting a second fluid which results, by the use thereof, in substantially maintaining the increased crosssectional area after the pressure is reduced.
Inventors
- 👤 Donald H Davidson
- 👤 Ray V Huff
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 16:45
CPC Classifications
E; E21; E21B; E21B43/00; E21B43/28; E21B43/283; C; C09; C09K; C09K8/00; C09K8/60; C09K8/80
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
158 words
IN A HYDROMETALLURGICAL OPERATION FOR THE IN-SITU UNDERGROUND MINING OF A LOW GRADE COPPER-CONTAINING IGNEOUS ROCK FORMATION BY THE USE OF A COPPER LEACHING SOLUTION FOR EXTRACING COPPER VALUES FROM SAID FORMATION WHEREIN AT LEAST ONE WELL EXTENDS FROM THE SURFACE OF THE EARTH INTO THE FORMATION THE IMPROVEMENT WHICH COMPRISES THE STEPS OF, PRIOR TO CONTACTING SAID COPPER-CONTAINING FORMATION WITH SAID LEACHING SOLUTION, INJECTING, AT A PRESSURE BELOW THE PRESSURE PRODUCING NEW FRACTURES IN THE FORMATION, A HYDRAULIC FLUID THROUGH SAID WELL INTO THE FORMATION AT A PRESSURE SUFFICIENT WHEREBY SAID FLUID DIFFUSES INTO THE NATURAL FRACTURES OF THE FORMATION SURROUNDING SAID WELL AND CAUSES SAID NATURAL FRACTURES TO INCREASE IN AT LEAST THE CROSS-SECTIONAL AREA THEREOF AND WHILE MAINTAINING SAID PRESSURE, INJECTING A SECOND FLUID INTO SAID NATURAL FRACTURES THROUGH SAID WELL WHEREBY THE USE OF SAID SECOND FLUID SUBSTANTIALLY RESULTS IN MAINTAINING THE INCREASED CROSS-SECTIONAL AREA OF SAID NATURAL FRACTURES AFTER THE PRESSURE IS REDUCED.
Claim 2
Dependent Claim
158 words
IN A HYDROMETALLURGICAL OPERATION FOR THE IN-SITU UNDERGROUND MINING OF A LOW GRADE COPPER-CONTAINING IGNEOUS ROCK FORMATION BY THE USE OF A COPPER LEACHING SOLUTION FOR EXTRACING COPPER VALUES FROM SAID FORMATION WHEREIN AT LEAST ONE WELL EXTENDS FROM THE SURFACE OF THE EARTH INTO THE FORMATION THE IMPROVEMENT WHICH COMPRISES THE STEPS OF, PRIOR TO CONTACTING SAID COPPER-CONTAINING FORMATION WITH SAID LEACHING SOLUTION, INJECTING, AT A PRESSURE BELOW THE PRESSURE PRODUCING NEW FRACTURES IN THE FORMATION, A HYDRAULIC FLUID THROUGH SAID WELL INTO THE FORMATION AT A PRESSURE SUFFICIENT WHEREBY SAID FLUID DIFFUSES INTO THE NATURAL FRACTURES OF THE FORMATION SURROUNDING SAID WELL AND CAUSES SAID NATURAL FRACTURES TO INCREASE IN AT LEAST THE CROSS-SECTIONAL AREA THEREOF AND WHILE MAINTAINING SAID PRESSURE, INJECTING A SECOND FLUID INTO SAID NATURAL FRACTURES THROUGH SAID WELL WHEREBY THE USE OF SAID SECOND FLUID SUBSTANTIALLY RESULTS IN MAINTAINING THE INCREASED CROSS-SECTIONAL AREA OF SAID NATURAL FRACTURES AFTER THE PRESSURE IS REDUCED.
Claim 3
Dependent Claim
64 words
The method as set forth in claim 1 wherein the hydraulic fluid is water which is injected into said well of from 1,000 feet to 10,000 feet deep at a pressure of from about 1,000 psig to about 10,000 psig, wherein said pressure is less than about 1.0 psig per foot of well depth, and below the pressure producing new fractures in the formation.
Claim 4
Dependent Claim
15 words
The method as set forth in claim 1 wherein the formation contains chalcopyrite and pyrite.
Claim 5
Dependent Claim
36 words
The method as set forth in claim 1 wherein said second fluid is an acidic solution which is capable of reacting with said igneous rock to increase at least the cross-sectional area of said natural fractures.
Claim 6
Dependent Claim
19 words
The method as set forth in claim 4 wherein said acidic solution comprises a mixture of HF and HCl.
Claim 7
Dependent Claim
19 words
The method as set forth in claim 4 wherein said acidic solution comprises a mixture of H2SO4 and HCl.
Claim 8
Dependent Claim
27 words
The process of claim 1 wherein said second fluid is selected from the group consisting of propping agents, acidic solutions, alkaline solutions, oxidizing agents and mixtures thereof.
Claim 9
Dependent Claim
11 words
The process of claim 1 wherein said second fluid is ammoniacal.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-11-03 | 1979-05-05 | 1979-11-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-11-03 | 1983-05-05 | 1983-11-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-11-03 | 1987-05-05 | 1987-11-04 | $7700.00 | Window Closed / Lapsed |