US5010301A
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Method for determining the swelling clay content of cement mixtures by dielectric measurements
Assignee: ExxonMobil Upstream Research Co
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Filing: 1989-08-22
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Granted: 1991-04-23
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Expires: 2009-08-22
Abstract
Abstract A method for determining at wellsites the swelling-clay content of cement mixtures by high-frequency dielectric measurements including: grinding a cement mix sample to a size suitable for testing; washing the cement mix sample with a fluid having a water activity substantially less than water, which may contain a soluble cation; packing the washed cement mix sample into a sample cell suitable for dielectric measurement; measuring the dielectric constant at a preselected frequency; and comparing the measured dielectric constant of the cement mix sample to calibration curves.
Inventors
- 👤 Peter K. Leung
- 👤 Ronald P. Steiger
- 👤 Kenneth R. Kunze
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 19:08
CPC Classifications
G; G01; G01N; G01N33/00; G01N33/38; G01N33/383; G01N27/00; G01N27/02; G01N27/22; G01N27/221
Claims Analysis
Total Claims: 25
Claim 1
Independent Claim
83 words
A method for measuring the swelling-clay content of wet cement mixtures by dielectric measurements, comprising the steps of: (a) washing a wet cement mix sample with a fluid having a water activity substantially less than that of water; (b) packing the washed cement mix sample into a sample cell suitable for dielectric measurement; (c) measuring the dielectric constant at a preselected frequency; and (d) comparing the measured dielectric constant of the cement mix sample to a calibration curve to determine the swelling-clay content.
Claim 2
Independent Claim
83 words
A method for measuring the swelling-clay content of wet cement mixtures by dielectric measurements, comprising the steps of: (a) washing a wet cement mix sample with a fluid having a water activity substantially less than that of water; (b) packing the washed cement mix sample into a sample cell suitable for dielectric measurement; (c) measuring the dielectric constant at a preselected frequency; and (d) comparing the measured dielectric constant of the cement mix sample to a calibration curve to determine the swelling-clay content.
Claim 3
Independent Claim
93 words
A method for measuring the swelling-clay content of cement mixtures by dielectric measurements, comprising the steps of: (a) grinding a cement mix sample to a size suitable for testing; (b) washing the cement mix sample with a fluid having a water activity substantially less than that of water; (c) packing the washed cement mix sample into a sample cell suitable for dielectric measurement; (d) measuring the dielectric constant at a preselected frequency; and (e) comparing the measured dielectric constant of the cement mix sample to a calibration curve to determine the swelling-clay content.
Claim 4
Independent Claim
93 words
A method for measuring the swelling-clay content of cement mixtures by dielectric measurements, comprising the steps of: (a) grinding a cement mix sample to a size suitable for testing; (b) washing the cement mix sample with a fluid having a water activity substantially less than that of water; (c) packing the washed cement mix sample into a sample cell suitable for dielectric measurement; (d) measuring the dielectric constant at a preselected frequency; and (e) comparing the measured dielectric constant of the cement mix sample to a calibration curve to determine the swelling-clay content.
Claim 5
Dependent Claim
23 words
The method of claim 1 or 2 further including the step of repeating steps a through e for each sample to be compared.
Claim 6
Dependent Claim
17 words
The method of claim 1 or 2 wherein said fluid is a mixture of alcohol and water.
Claim 7
Dependent Claim
22 words
The method of claim 1 or 2 wherein said fluid is a mixture of 70% (volume) isopropyl alcohol and 30% (volume) water.
Claim 8
Dependent Claim
17 words
The method of claim 1 or 2 wherein said packing is accomplished by centrifuging the sample cell.
Claim 9
Dependent Claim
17 words
The method of claim 1 or 2 wherein the preselected frequency of measurement is about 1 megahertz.
Claim 10
Independent Claim
183 words
A method for measuring the swelling-clay content of cement mixtures by high-frequency dielectric measurements, comprising the steps of: (a) grinding a cement mix sample to a predetermined size suitable for testing; (b) washing the cement mix sample with a fluid having a water activity substantially less than that of water; (c) packing the washed cement mix sample into a sample cell suitable for dielectric measurement; (d) measuring the dielectric constant at a preselected frequency to allow uniform comparison of cement mix samples; and (e) repeating steps a through d for a sample of pure swellable clay; (f) repeating steps a through d for a sample of pure cement; (g) obtaining the swelling-clay content of the cement mix in accordance with the following relationship: ##EQU2## where: DCM cement mix is the measured dielectric constant of the cement mix sample; DCM pure cement is the measured dielectric constant of the pure cement sample; DCM pure swellable clay is the measured dielectric constant of te pure swellable clay sample; and a is the amount swelling-clay content in the cement mix in a fraction of total weight.
Claim 11
Independent Claim
183 words
A method for measuring the swelling-clay content of cement mixtures by high-frequency dielectric measurements, comprising the steps of: (a) grinding a cement mix sample to a predetermined size suitable for testing; (b) washing the cement mix sample with a fluid having a water activity substantially less than that of water; (c) packing the washed cement mix sample into a sample cell suitable for dielectric measurement; (d) measuring the dielectric constant at a preselected frequency to allow uniform comparison of cement mix samples; and (e) repeating steps a through d for a sample of pure swellable clay; (f) repeating steps a through d for a sample of pure cement; (g) obtaining the swelling-clay content of the cement mix in accordance with the following relationship: ##EQU2## where: DCM cement mix is the measured dielectric constant of the cement mix sample; DCM pure cement is the measured dielectric constant of the pure cement sample; DCM pure swellable clay is the measured dielectric constant of te pure swellable clay sample; and a is the amount swelling-clay content in the cement mix in a fraction of total weight.
Claim 12
Dependent Claim
21 words
The method of claim 8, further including the step of repeating steps a through g for each sample to be compared.
Claim 13
Dependent Claim
15 words
The method of claim 8 wherein said fluid is a mixture of alcohol and water.
Claim 14
Dependent Claim
17 words
The method of claim 10 wherein said mixture is 70% (volume) isopropyl alcohol and 30% (volume) water.
Claim 15
Dependent Claim
15 words
The method of claim 8 wherein said packing is accomplished by centrifuging the sample cell.
Claim 16
Dependent Claim
15 words
The method of claim 8 wherein the preselected frequency of measurement is about 1 megahertz.
Claim 17
Independent Claim
116 words
A method for measuring the swelling-clay content of cement mixtures by high-frequency dielectric measurements, comprising the steps of: (a) grinding a dried cement mix sample to a predetermined size suitable for testing; (b) washing the cement mix sample with a fluid having a water activity substantially less than that of water to which a cation has been added; (c) packing the washed cement mix sample into a sample cell suitable for dielectric measurement; (d) measuring the dielectric constant at a preselected frequency to allow uniform comparison of cement mix samples; and (e) comparing the measured dielectric constant of the cement mix sample to a calibration curve derived from samples of known dielectric constant and swelling-clay content.
Claim 18
Independent Claim
116 words
A method for measuring the swelling-clay content of cement mixtures by high-frequency dielectric measurements, comprising the steps of: (a) grinding a dried cement mix sample to a predetermined size suitable for testing; (b) washing the cement mix sample with a fluid having a water activity substantially less than that of water to which a cation has been added; (c) packing the washed cement mix sample into a sample cell suitable for dielectric measurement; (d) measuring the dielectric constant at a preselected frequency to allow uniform comparison of cement mix samples; and (e) comparing the measured dielectric constant of the cement mix sample to a calibration curve derived from samples of known dielectric constant and swelling-clay content.
Claim 19
Dependent Claim
66 words
The method of claim 14 wherein said cation comprises Li + , Na + , K + , Rb + , Cs + , (NH 4 ) + , Mg +2 , Ca +2 , Ba +2 , Sr +2 , Co +2 , Ni +2 , Cu +2 , Zn +2 , La +3 , Fe +3 , Cr +3 , or Al +3 .
Claim 20
Dependent Claim
15 words
The method of claim 14 wherein said fluid is a mixture of alcohol and water.
Claim 21
Dependent Claim
17 words
The method of claim 16 wherein said mixture is 70% (volume) isopropyl alcohol and 30% (volume) water.
Claim 22
Dependent Claim
15 words
The method of claim 14 wherein said packing is accomplished by centrifuging the sample cell.
Claim 23
Dependent Claim
15 words
The method of claim 14 wherein the preselected frequency of measurement is about 1 megahertz.
Claim 24
Dependent Claim
21 words
The method of claim 14, further including the step of repeating steps a through e for each sample to be compared.
Claim 25
Dependent Claim
81 words
The method of claim 14, wherein the swelling-clay content of the cement mix is determined in accordance with the following relationship: ##EQU3## where: DCM cement mix is the measured dielectric constant of the cement mix sample; DCM pure cement is the measured dielectric constant of the pure cement sample; DCM pure swellable clay is the measured dielectric constant of te pure swellable clay sample; and a is the amount swelling-clay content in the cement mix in a fraction of total weight.
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