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Fracture mechanics: Difference between revisions
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''ν'' = Poisson | ''ν'' = Poisson | ||
<nowiki>’</nowiki> | <nowiki>’</nowiki> | ||
s ratio, ''σ''<sub>1</sub> = overburden stress, | s ratio, ''σ''<sub>1</sub> = overburden stress, ''α'' = Biot<nowiki>’</nowiki> | ||
''α'' = Biot | s constant, ''p''<sub>''p''</sub> = reservoir fluid pressure or pore pressure, and ''σ''<sub>ext</sub> = tectonic stress. | ||
<nowiki>’</nowiki> | |||
s constant, ''p''<sub>''p''</sub> = reservoir fluid pressure or pore pressure, and | |||
''σ''<sub>ext</sub> = tectonic stress. | |||
Poisson | Poisson | ||
<nowiki>’</nowiki> | <nowiki>’</nowiki> | ||
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s constant is usually 1.0, but can be less than 1.0 on occasion. <gallery widths="300px" heights="200px"> | s constant is usually 1.0, but can be less than 1.0 on occasion. <gallery widths="300px" heights="200px"> | ||
File:Vol4prt Page 329 Image 0001.png|'''Table 1- Table Range Of Values For Young Modulus''' | File:Vol4prt Page 329 Image 0001.png|'''Table 1- Table Range Of Values For Young Modulus''' | ||
</gallery> | </gallery> Poroelastic theory is often used to estimate the minimum horizontal stress.<ref name="r4">Whitehead, W.S., Hunt, E.R., and Holditch, S.A. 1987. The Effects of Lithology and Reservoir Pressure on the In-Situ Stresses in the Waskom (Travis Peak) Field. Presented at the Low Permeability Reservoirs Symposium, Denver, Colorado, USA, 18–19 May. SPE-16403-MS. http://dx.doi.org/10.2118/16403-MS.</ref><ref name="r5">Salz, L.B. 1977. Relationship Between Fracture Propagation Pressure and Pore Pressure. Presented at the SPE Annual Fall Technical Conference and Exhibition, Denver, Colorado, USA, 9–12 October. SPE-6870-MS. http://dx.doi.org/10.2118/6870-MS._</ref><ref name="r6">Veatch Jr., R.W. and Moschovidis, Z.A. 1986. An Overview of Recent Advances in Hydraulic Fracturing Technology. Presented at the International Meeting on Petroleum Engineering, Beijing, China, 17-20 March. SPE-14085-MS. http://dx.doi.org/10.2118/14085-MS.</ref> '''Eq. 1''' combines poroelastic theory with a term that accounts for any tectonic forces that are acting on a formation. The first term on the right side of '''Eq. 1''' is a linear elastic term that converts the effective vertical stress on the rock grains into an effective horizontal stress on the rock grains. The second term in Eq. 1 represents the stress generated by the fluid pressure in the pore space. The third term is the tectonic stress, which could be zero in tectonically relaxed areas, but can be important in tectonically active areas. | ||
Poroelastic theory is often used to estimate the minimum horizontal stress.<ref name="r4">Whitehead, W.S., Hunt, E.R., and Holditch, S.A. 1987. The Effects of Lithology and Reservoir Pressure on the In-Situ Stresses in the Waskom (Travis Peak) Field. Presented at the Low Permeability Reservoirs Symposium, Denver, Colorado, USA, 18–19 May. SPE-16403-MS. http://dx.doi.org/10.2118/16403-MS.</ref><ref name="r5">Salz, L.B. 1977. Relationship Between Fracture Propagation Pressure and Pore Pressure. Presented at the SPE Annual Fall Technical Conference and Exhibition, Denver, Colorado, USA, 9–12 October. SPE-6870-MS. http://dx.doi.org/10.2118/6870-MS._</ref><ref name="r6">Veatch Jr., R.W. and Moschovidis, Z.A. 1986. An Overview of Recent Advances in Hydraulic Fracturing Technology. Presented at the International Meeting on Petroleum Engineering, Beijing, China, 17-20 March. SPE-14085-MS. http://dx.doi.org/10.2118/14085-MS.</ref> '''Eq. 1''' combines poroelastic theory with a term that accounts for any tectonic forces that are acting on a formation. The first term on the right side of '''Eq. 1''' is a linear elastic term that converts the effective vertical stress on the rock grains into an effective horizontal stress on the rock grains. The second term in Eq. 1 represents the stress generated by the fluid pressure in the pore space. The third term is the tectonic stress, which could be zero in tectonically relaxed areas, but can be important in tectonically active areas. | |||
In tectonically active areas, the effects of tectonic activity must be included in the analyses of the total stresses. To measure the tectonic stresses, injection tests are conducted to measure the minimum horizontal stress. The measured stress is then compared with the stress calculated by the poroelastic equation to determine the value of the tectonic stress. | In tectonically active areas, the effects of tectonic activity must be included in the analyses of the total stresses. To measure the tectonic stresses, injection tests are conducted to measure the minimum horizontal stress. The measured stress is then compared with the stress calculated by the poroelastic equation to determine the value of the tectonic stress. | ||
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== External links == | == External links == | ||
Xiong, Hongjie. 2017. "Optimizing Cluster or Fracture Spacing: An Overview." The Way Ahead. Society of Petroleum Engineers. https://www.spe.org/en/twa/twa-article-detail/?art=3007 | |||
[http://store.spe.org/Recent-Advances-In-Hydraulic-Fracturing--P66.aspx Recent Advances In Hydraulic Fracturing] | [http://store.spe.org/Recent-Advances-In-Hydraulic-Fracturing--P66.aspx Recent Advances In Hydraulic Fracturing] | ||
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== Page champions == | == Page champions == | ||
[www.linkedin.com/in/renealcalde Rene Alcalde] | [https://www.linkedin.com/in/renealcalde Rene Alcalde] | ||
== Category == | == Category == | ||
[[Category:2.5 Hydraulic fracturing]] [[Category:YR]] | [[Category:2.5 Hydraulic fracturing]] [[Category:YR]] | ||