Cement having stress-indicating properties
A system and method measures subterranean stress. The system and method includes a cement mixture that is mixed with water to set as a solid and a stress measuring-medium having piezospectroscopic properties that directly reveals stress in situ within the cement mixture in response to a photo stimulation. The stress measuring-medium combines with the cement mixture as a dry blend before being combined with water.
1. A stress sensor system that measures subterranean stress in situ comprising:
a cement mixture that is mixed with water to set as a solid material; and
a stress measuring-medium having piezospectroscopic properties that directly reveals stress in situ within the cement mixture in response to a photo stimulation by measuring an absorption of an incident light non-radiatively de-excited to about 14400 cm −1 ;
where the stress measuring-medium is combined with the cement mixture and water.
2. The system of claim 1 further comprising an expansive mineral additive combined with the stress measuring-medium.
3. The system of claim 2 further comprising a water-reducing admixture combined with the stress measuring-medium.
4. The system of claim 1 where the stress measuring-medium comprises an alpha-alumina material.
5. The system of claim 1 where the stress measuring-medium comprises an alpha-alumina material and a chromia material.
6. The system of claim 1 where the cement mixture comprises a Portland cement that forms a hydraulic seal with an alpha-alumina material.
7. The system of claim 1 where the cement mixture comprises a calcium sulfoaluminate cement added to a class H cement that forms a hydraulic seal with a alpha-alumina material.
8. A stress sensor that measures subterranean stress in situ comprising:
a cement mixture that is mixed with water to set as a solid material; and
a stress measuring-medium having piezospectroscopic properties that directly reveals stress in situ within the cement mixture in response to a photo stimulation;
where the stress measuring-medium is combined with the cement mixture and water; and
where the stress sensor renders a spectral resolution of 0.01 cm −1 at about 1443 cm −1 .
9. A method for measuring subterranean stress in situ comprising:
mixing a water reducing admixture with water to render a mixture;
dry blending a cement mixture, an expansive mineral additive, and a stress measuring-medium in a dry blend; and
mixing progressively the dry blend to obtain a homogeneous cement slurry; and
where the stress measuring medium comprises about a fifty-five percent dry blend by weight of a total weight of the cement mixture;
where the stress measuring medium renders a spectral resolution of about 0.01 cm −1 at about 1443 cm −1 .
10. The method of claim 9 where the stress measuring-medium comprises an alpha-alumina material.
11. The method of claim 9 where the stress measuring-medium comprises an alpha-alumina material and a chromia material.
12. The method of claim 9 where the cement mixture comprises a Portland cement that forms a hydraulic seal with an alpha-alumina material.
13. The method of claim 9 where the cement mixture comprises a calcium sulfoaluminate cement added to a class H cement that forms a hydraulic seal with an alpha-alumina material.
14. The method of claim 9 where the stress measuring medium comprises a processed alumina heated up and until 950° C.
15. A stress sensor system that measures subterranean stress in situ comprising:
a cement mixture that is mixed with water to set as a solid material; and
an alpha-alumina compound having piezospectroscopic properties that directly reveals stress in situ within the cement mixture in response to a photo stimulation;
where the alpha-alumina compound is combined with the cement mixture; and
where the stress sensor renders a spectral resolution between 0.0095 cm −1 and 0.01 cm −1 at between 14400 cm −1 and 1443 cm −1 .
16. The system of claim 15 further comprising an expansive mineral additive combined with the alpha-alumina compound.
17. The system of claim 16 further comprising a water-reducing admixture combined with the alpha-alumina compound.
18. The system of claim 15 where the alpha-alumina compound comprises an alpha-alumina material and a chromia material.