Mechanistic Study of Microbial Altered Properties in Dolostones.
Saved in:
| Title: | Mechanistic Study of Microbial Altered Properties in Dolostones. |
|---|---|
| Authors: | Kolawole, Oladoyin1 (AUTHOR) oladoyin.kolawole@njit.edu |
| Source: | Rock Mechanics & Rock Engineering. Feb2023, Vol. 56 Issue 2, p1099-1111. 13p. |
| Subjects: | Dolomite, Sedimentary rocks, Young's modulus, Elasticity, Drill core analysis, Rock properties, Bacterial leaching |
| Abstract: | In this study, a suite of tests was conducted to investigate the microscale mechanical, elastic, and microstructural alterations due to rock–microbial interactions in dolomitic rocks (dolostones) at elevated treatment (temperature and pressure) conditions. Dolostone samples were treated with a microbial media, and the microscale mechanical and elastic responses and the unit weight changes due to the rock–microbial interaction in dolotstones were quantified. Subsequently, a new relationship for estimating dynamic Young's modulus (E) of rocks from scratch test was proposed. The microstructural alteration during the process was reported using scanning electron microscopy (SEM). The results of rock–microbial interactions in dolostone indicate potential: (i) mechanical alterations with distinct low and peak values in investigated core samples; (ii) enhancement in mechanical and elastic properties and the mechanical integrity (−37% Poisson's ratio, ν; +320% scratch-derived Young's modulus, Escr; +80% unconfined compressive strength, UCS; +223% scratch toughness, Ks); (iii) increase in pore throat clogging and unit weight (+ 33%) due to mineral precipitations, which can occlude and cement the pore spaces in dolostones and increase the intergranular-bonding integrity. The results also suggest a greater rock–microbial impact in dolostones relative to shales, due to higher inherent pores and permeable fractures in dolostones which might have accelerated microbial actions at farther reach. Further, this study provides new insights into understanding the coupled rock–microbial interaction in dolostones, and proposes Escr as an alternate method for estimating the Young's modulus of sedimentary rocks from scratch tests. Highlights: Microbial-induced changes in rock strength, stiffness, and microstructural properties of dolomite-rich rocks are investigated. Subsurface dolostone samples are microbially treated at near in-situ conditions. In-situ microbial-induced changes significantly improved the strength and stiffness of dolostones. Microbial–rock interactions increased the mineral filling and cementation of inter-grain pores, and improved the unit weight in dolostones. A novel relationship is proposed for estimating Young's modulus of sedimentary rocks from scratch tests. [ABSTRACT FROM AUTHOR] |
| Copyright of Rock Mechanics & Rock Engineering is the property of Springer Nature and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.) | |
| Database: | Engineering Source |
|
Full text is not displayed to guests.
Login for full access.
|
|
| Abstract: | In this study, a suite of tests was conducted to investigate the microscale mechanical, elastic, and microstructural alterations due to rock–microbial interactions in dolomitic rocks (dolostones) at elevated treatment (temperature and pressure) conditions. Dolostone samples were treated with a microbial media, and the microscale mechanical and elastic responses and the unit weight changes due to the rock–microbial interaction in dolotstones were quantified. Subsequently, a new relationship for estimating dynamic Young's modulus (E) of rocks from scratch test was proposed. The microstructural alteration during the process was reported using scanning electron microscopy (SEM). The results of rock–microbial interactions in dolostone indicate potential: (i) mechanical alterations with distinct low and peak values in investigated core samples; (ii) enhancement in mechanical and elastic properties and the mechanical integrity (−37% Poisson's ratio, ν; +320% scratch-derived Young's modulus, Escr; +80% unconfined compressive strength, UCS; +223% scratch toughness, Ks); (iii) increase in pore throat clogging and unit weight (+ 33%) due to mineral precipitations, which can occlude and cement the pore spaces in dolostones and increase the intergranular-bonding integrity. The results also suggest a greater rock–microbial impact in dolostones relative to shales, due to higher inherent pores and permeable fractures in dolostones which might have accelerated microbial actions at farther reach. Further, this study provides new insights into understanding the coupled rock–microbial interaction in dolostones, and proposes Escr as an alternate method for estimating the Young's modulus of sedimentary rocks from scratch tests. Highlights: Microbial-induced changes in rock strength, stiffness, and microstructural properties of dolomite-rich rocks are investigated. Subsurface dolostone samples are microbially treated at near in-situ conditions. In-situ microbial-induced changes significantly improved the strength and stiffness of dolostones. Microbial–rock interactions increased the mineral filling and cementation of inter-grain pores, and improved the unit weight in dolostones. A novel relationship is proposed for estimating Young's modulus of sedimentary rocks from scratch tests. [ABSTRACT FROM AUTHOR] |
|---|---|
| ISSN: | 07232632 |
| DOI: | 10.1007/s00603-022-03116-y |
