Compressional wave dispersion due to rock matrix stiffening by clay squirt flow
Abstract The standard Biot‐Gassmann theory of poroelasticity fails to explain strong compressional wave velocity dispersion experimentally observed in 12 tight siltstone with clay‐filled pores. In order to analyze and understand the results, we developed a new double‐porosity model of clay squirt fl...
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| Format: | Article |
| Language: | English |
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Wiley
2016-06-01
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| Series: | Geophysical Research Letters |
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| Online Access: | https://doi.org/10.1002/2016GL069312 |
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| author | Jing Ba Jianguo Zhao José M. Carcione Xingxing Huang |
| author_facet | Jing Ba Jianguo Zhao José M. Carcione Xingxing Huang |
| author_sort | Jing Ba |
| collection | DOAJ |
| description | Abstract The standard Biot‐Gassmann theory of poroelasticity fails to explain strong compressional wave velocity dispersion experimentally observed in 12 tight siltstone with clay‐filled pores. In order to analyze and understand the results, we developed a new double‐porosity model of clay squirt flow where wave‐induced local fluid flow occurs between the micropores in clay aggregates and intergranular macropores. The model is validated based on the combined study of ultrasonic experiments on specimens at different saturation conditions and theoretical predictions. The presence of a sub‐pore‐scale structure of clay micropores contained in intergranular macropores, where the fluid does not have enough time to achieve mechanical equilibrium at ultrasonic frequencies and thus stiffens the rock matrix, provides a suitable explanation of the experimental data. Moreover, the model provides a new bound for estimating the compressional wave velocity of tight rocks saturated with two immiscible liquids. The theoretical predictions indicate that the velocity variation between gas‐ and liquid‐saturated specimens is predominantly induced by the clay squirt stiffening effect on the rock matrix and not by fluid substitution. The effect contributes more than 90% to the variation in the porosity range of 0–5%. Thus, clay squirt flow dominates the relationships between compressional wave velocity and pore fluid in tight rocks. |
| format | Article |
| id | doaj-art-3d19f6bab5774119b50955a3fc0cf142 |
| institution | Kabale University |
| issn | 0094-8276 1944-8007 |
| language | English |
| publishDate | 2016-06-01 |
| publisher | Wiley |
| record_format | Article |
| series | Geophysical Research Letters |
| spelling | doaj-art-3d19f6bab5774119b50955a3fc0cf1422025-08-20T03:49:37ZengWileyGeophysical Research Letters0094-82761944-80072016-06-0143126186619510.1002/2016GL069312Compressional wave dispersion due to rock matrix stiffening by clay squirt flowJing Ba0Jianguo Zhao1José M. Carcione2Xingxing Huang3School of Earth Science and Engineering Hohai University Nanjing ChinaState Key Laboratory of Petroleum Resources and Prospecting China University of Petroleum (Beijing) Beijing ChinaIstituto Nazionale di Oceanografia e di Geofisica Sperimentale Sgonico ItalyState Key Laboratory of Petroleum Resources and Prospecting China University of Petroleum (Beijing) Beijing ChinaAbstract The standard Biot‐Gassmann theory of poroelasticity fails to explain strong compressional wave velocity dispersion experimentally observed in 12 tight siltstone with clay‐filled pores. In order to analyze and understand the results, we developed a new double‐porosity model of clay squirt flow where wave‐induced local fluid flow occurs between the micropores in clay aggregates and intergranular macropores. The model is validated based on the combined study of ultrasonic experiments on specimens at different saturation conditions and theoretical predictions. The presence of a sub‐pore‐scale structure of clay micropores contained in intergranular macropores, where the fluid does not have enough time to achieve mechanical equilibrium at ultrasonic frequencies and thus stiffens the rock matrix, provides a suitable explanation of the experimental data. Moreover, the model provides a new bound for estimating the compressional wave velocity of tight rocks saturated with two immiscible liquids. The theoretical predictions indicate that the velocity variation between gas‐ and liquid‐saturated specimens is predominantly induced by the clay squirt stiffening effect on the rock matrix and not by fluid substitution. The effect contributes more than 90% to the variation in the porosity range of 0–5%. Thus, clay squirt flow dominates the relationships between compressional wave velocity and pore fluid in tight rocks.https://doi.org/10.1002/2016GL069312clay squirt flowsubmicrostructureswave propagationelasticity and anelasticityP wave dispersionacoustic properties |
| spellingShingle | Jing Ba Jianguo Zhao José M. Carcione Xingxing Huang Compressional wave dispersion due to rock matrix stiffening by clay squirt flow Geophysical Research Letters clay squirt flow submicrostructures wave propagation elasticity and anelasticity P wave dispersion acoustic properties |
| title | Compressional wave dispersion due to rock matrix stiffening by clay squirt flow |
| title_full | Compressional wave dispersion due to rock matrix stiffening by clay squirt flow |
| title_fullStr | Compressional wave dispersion due to rock matrix stiffening by clay squirt flow |
| title_full_unstemmed | Compressional wave dispersion due to rock matrix stiffening by clay squirt flow |
| title_short | Compressional wave dispersion due to rock matrix stiffening by clay squirt flow |
| title_sort | compressional wave dispersion due to rock matrix stiffening by clay squirt flow |
| topic | clay squirt flow submicrostructures wave propagation elasticity and anelasticity P wave dispersion acoustic properties |
| url | https://doi.org/10.1002/2016GL069312 |
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