Back to results
US 10,481,143 B2Granted
Chemo-thermo-piezoresistive highly sensing smart cement with integrated real-time monitoring system
AssigneeUniversity of Houston System
InventorCumaraswamy Vipulanandan
Life of this patent
Estimating the term…
Abstract
The chemo-thermo-piezoresistive behavior of so-called “smart cement,” or cement modified with conductive fillers, is useful as a bulk sensor for monitoring the changes in the cement due to stresses, cracks, contamination, fluid loss, and temperature change that affect its performance. The smart cement utilizes a special conductive or semi-conductive filler and is useful as a bulk sensor that allows real-time monitoring of its properties.
Claims12
A system for monitoring performance-related properties of cement, comprising:
- a cement structure comprised of chemo-thermo-piezoresistive smart cement, wherein the chemo-thermo-piezoresistive smart cement comprises from about 0.03% to about 0.1% modified conductive or semi-conductive filler by weight of the chemo-thermo-piezoresistive smart cement, and wherein the modified conductive or semi-conductive filler comprises dispersed carbon fibers, dispersed basaltic fibers, or mixtures thereof;
- and
- an integrated real-time monitoring system for monitoring changes in electrical resistivity of the chemo-thermo-piezoresistive smart cement, wherein the changes in the electrical resistivity of the chemo-thermo-piezoresistive smart cement correlate with performance-related properties of the chemo-thermo-piezoresistive smart cement, wherein the integrated real-time monitoring system collects AC resistance measurements at selected frequencies, wherein the integrated real-time monitoring system uses the AC resistance measurements to calculate the changes in the electrical resistivity and changes in electrical impedance of the chemo-thermo-piezoresistive smart cement using an equivalent circuit to represent electrical properties of the chemo-thermo-piezoresistive smart cement, wherein the chemo-thermo-piezoresistive smart cement is represented in the equivalent circuit as a bulk material with contacts as follows:
- Z
- 2
-
- (
- σ
- )
- =
- R
- b
-
- (
- σ
- )
- +
- 2
-
-
- R
- c
-
- (
- σ
- )
- 1
- +
- ω
- 2
-
- R
- c
- 2
-
- C
- c
- 2
- -
- j
-
-
- 2
-
-
- ω
-
-
- R
- c
- 2
-
- C
- c
-
- (
- σ
- )
- 1
- +
- ω
- 2
-
- R
- c
- 2
-
- C
- c
- 2
- ,
- wherein Z2 is total electrical impedance for the equivalent circuit, Rb is resistance of the bulk material, Rc is resistance of the contacts, Cc is capacitance of the contacts, and ω is a selected frequency, and wherein the equivalent circuit assumes a negligible capacitance for the bulk material.
69 more elements
A method for real-time monitoring of performance-related properties of cement, comprising:
- constructing a cement structure, wherein the cement structure comprises chemo-thermo-piezoresistive smart cement and an integrated real-time monitoring system for monitoring changes in electrical resistivity of the chemo-thermo-piezoresistive smart cement, wherein the chemo-thermo-piezoresistive smart cement comprises from about 0.03% to about 0.1% modified conductive or semi-conductive filler by weight of the chemo-thermo-piezoresistive smart cement, and wherein the modified conductive or semi-conductive filler comprises dispersed carbon fibers, dispersed basaltic fibers, or mixtures thereof;
- collecting AC resistance measurements of the chemo-thermo-piezoresistive smart cement at selected frequencies using the integrated real-time monitoring system;
- using the AC resistance measurements to calculate changes in the electrical resistivity of the chemo-thermo-piezoresistive smart cement and changes in electrical impedance of the chemo-thermo-piezoresistive smart cement using an equivalent circuit to represent electrical properties of the chemo-thermo-piezoresistive smart cement, wherein the chemo-thermo-piezoresistive smart cement is represented in the equivalent circuit as a bulk material with contacts as follows:
- Z
- 2
-
- (
- σ
- )
- =
- R
- b
-
- (
- σ
- )
- +
- 2
-
-
- R
- c
-
- (
- σ
- )
- 1
- +
- ω
- 2
-
- R
- c
- 2
-
- C
- c
- 2
- -
- j
-
-
- 2
-
-
- ω
-
-
- R
- c
- 2
-
- C
- c
-
- (
- σ
- )
- 1
- +
- ω
- 2
-
- R
- c
- 2
-
- C
- c
- 2
- ,
- wherein Z2 is total electrical impedance for the equivalent circuit, Rb is resistance of the bulk material, Rc is resistance of the contacts, Cc is capacitance of the contacts, and ω is a selected frequency, and wherein the equivalent circuit assumes a negligible capacitance for the bulk material;
- and
- monitoring the changes in the electrical resistivity and the electrical impedance of the chemo-thermo-piezoresistive smart cement using the integrated real-time monitoring system, wherein the changes in the electrical resistivity of the chemo-thermo-piezoresistive smart cement correlate with performance-related properties of the chemo-thermo-piezoresistive smart cement.
71 more elements
Dependencies are inferred from the claim text.