US4283089A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Pretreatment for fracturing coal seams
Assignee: C0NSOLIDATION COAL Co
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Filing: 1980-06-12
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Granted: 1981-08-11
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Expires: 2000-06-12
Abstract
Abstract A pretreatment for use in fracturing coal seams to increase gas permeability of the seams. The pretreatment involves injecting a material capable of swelling coal into a coal seam prior to fracturing the coal seam. The pretreatment material swells the coal and closes the natural cleats therein, enhancing the effectiveness of the subsequent fracturing step.
Inventors
- 👤 Raymond L. Mazza
- 👤 H. Douglas Dahl
- 👤 Ronald W. Umphrey
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 10:45
CPC Classifications
E; E21; E21B; E21B43/00; E21B43/25; E21B43/26; E21B43/2605; C; C09; C09K; C09K8/00; C09K8/60; C09K8/62; C09K8/72; C09K8/74; E21B43/30; E21F; E21F7/00
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
79 words
A method of pretreating and hyraulically fracturing a coal seam comprising: (a) injecting a pretreatment material capable of swelling coal into a coal seam to be fractured, said material being injected at less than fracturing pressure; (b) allowing the coal seam to swell as a result of contact with said material, thereby reducing the permeability of cleats in the pretreated portion of said coal seam; and (c) subsequently subjecting said pretreated portion of said coal seam to hydraulic fracturing.
Claim 2
Independent Claim
79 words
A method of pretreating and hyraulically fracturing a coal seam comprising: (a) injecting a pretreatment material capable of swelling coal into a coal seam to be fractured, said material being injected at less than fracturing pressure; (b) allowing the coal seam to swell as a result of contact with said material, thereby reducing the permeability of cleats in the pretreated portion of said coal seam; and (c) subsequently subjecting said pretreated portion of said coal seam to hydraulic fracturing.
Claim 3
Dependent Claim
20 words
The method of claim 1 wherein said pretreatment material is selected from the group consisting of ammonia and hydrogen chloride.
Claim 4
Dependent Claim
12 words
The method of claim 1 wherein said pretreatment material is liquid ammonia.
Claim 5
Dependent Claim
39 words
The method of claim 1 wherein methane gas is to be produced from said coal seam and said pretreatment and fracturing steps are applied to said coal seam in a pattern utilizing spacing of from 40 to 80 acres.
Claim 6
Dependent Claim
53 words
The method of claim 1 wherein said coal seam is to be mined and said pretreatment and fracturing steps are applied to said coal seam in a pattern outlining a portion of said coal seam to be mined utilizing a lineal spacing of from 2 to 3 times the length of fracture obtained.
Claim 7
Dependent Claim
25 words
The method of claim 5 wherein the pretreatment and fracturing steps are carried out near face cleats in the treated portion of the coal seam.
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) | 1984-08-10 | 1985-02-09 | 1985-08-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-08-10 | 1989-02-09 | 1989-08-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-08-10 | 1993-02-09 | 1993-08-11 | $7700.00 | Window Closed / Lapsed |