Patent US4493875A successfully refreshed from Google Patents.
US4493875A
Expired / Lapsed
US
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Proppant for well fractures and method of making same
Assignee: 3M Co
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Filing: 1983-12-09
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Granted: 1985-01-15
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Expires: 2003-12-09
Abstract
Abstract The novel proppant consists of composite particles, the core of which is a conventional proppant particle such as silica sand. The core has a thin, void-containing coating which provides an overall density approaching that of the fracturing fluid. The coating preferably comprises hollow glass microspheres embedded in an adhesive which bonds the microspheres to the core.
Inventors
- 👤 Warren R. Beck
- 👤 Richard B. Castle
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 22:39
CPC Classifications
C; C09; C09K; C09K8/00; C09K8/60; C09K8/80; C09K8/805; C09K8/62; E; E21; E21B; E21B43/00; E21B43/25; E21B43/26; E21B43/267; Y; Y10; Y10T; Y10T428/00; Y10T428/29; Y10T428/2982; Y10T428/2991; Y10T428/2993
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
49 words
A composite particle which is useful as a proppant and comprises (a) a high-strength core having a density of at least 2.2 g/cc, and (b) a thin void-containing coating of a density less than 0.8 g/cc, which composite particle has an overall average diameter from 0.2 to 3 mm.
Claim 2
Dependent Claim
49 words
A composite particle which is useful as a proppant and comprises (a) a high-strength core having a density of at least 2.2 g/cc, and (b) a thin void-containing coating of a density less than 0.8 g/cc, which composite particle has an overall average diameter from 0.2 to 3 mm.
Claim 3
Dependent Claim
20 words
A composite particle as defined in claim 1 wherein the coating comprises hollow ceramic microparticles adhesively bonded to the core.
Claim 4
Dependent Claim
15 words
A composite particle as defined in claim 2 wherein the ceramic microparticles are glass microspheres.
Claim 5
Dependent Claim
15 words
A composite particle as defined in claim 1 wherein the coating comprises a foamed ceramic.
Claim 6
Dependent Claim
13 words
A composite particle as defined in claim 4 wherein the ceramic is glass.
Claim 7
Dependent Claim
13 words
A composite particle as defined in claim 1 wherein the core is sand.
Claim 8
Dependent Claim
14 words
A composite particle as defined in claim 1 wherein the core is aluminum oxide.
Claim 9
Dependent Claim
14 words
A composite particle as defined in claim 1 wherein the core is a ceramic.
Claim 10
Dependent Claim
13 words
A composite particle as defined in claim 8 wherein the ceramic is glass.
Claim 11
Dependent Claim
20 words
A composite particle as defined in claim 1 wherein the core has a compressive strength of at least 1 GPa.
Claim 12
Dependent Claim
25 words
A proppant consisting of a great number of composite particles as defined in claim 1 having an average overall diameter from 0.3 to 1.0 mm.
Claim 13
Dependent Claim
26 words
A proppant as defined in claim 11 wherein the average thickness of the coatings is from 5 to 20% of the average diameter of the cores.
Claim 14
Dependent Claim
18 words
A proppant as defined in claim 12 wherein the coatings have a density from 0.15 to 0.6 g/cc.
Claim 15
Dependent Claim
21 words
A proppant as defined in claim 13 wherein the individual composite particles have a density from of 1.3 to 2.5 g/cc.
Claim 16
Dependent Claim
28 words
A proppant as defined in claim 13 wherein the void-containing coating of each composite particle comprises hollow ceramic microparticles having an average diameter from 20 to 50 micrometers.
Claim 17
Dependent Claim
14 words
Proppant as defined in claim 15 wherein the ceramic microparticles are hollow glass microspheres.
Claim 18
Dependent Claim
74 words
Method of making composite particles useful as proppants comprising the steps of: (1) mixing dense, high-strength core particles with adhesive to provide adhesive-coated particles, (2) while the adhesive is tacky, mixing the coated core particles with hollow ceramic microparticles to adhere a plurality of the microparticles to each coated core, and (3) curing the adhesive to a nontacky state while keeping the individual coated core particles substantially out of adherent contact with each other.
Claim 19
Dependent Claim
74 words
Method of making composite particles useful as proppants comprising the steps of: (1) mixing dense, high-strength core particles with adhesive to provide adhesive-coated particles, (2) while the adhesive is tacky, mixing the coated core particles with hollow ceramic microparticles to adhere a plurality of the microparticles to each coated core, and (3) curing the adhesive to a nontacky state while keeping the individual coated core particles substantially out of adherent contact with each other.
Claim 20
Dependent Claim
18 words
Method as defined in claim 17 wherein steps 1 and 2 are sequentially repeated prior to step 3.
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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) | 1988-01-15 | 1988-07-16 | 1989-01-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-01-15 | 1992-07-16 | 1993-01-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-01-15 | 1996-07-16 | 1997-01-15 | $7700.00 | Window Closed / Lapsed |