Analysis of borehole stability in gas drilling using a thermal elastoplastic coupling model

Abstract Gas drilling causes lower pressure in the borehole and the Joule‐Thomson effect to occur at the bit nozzle, resulting in a temperature distribution in the borehole different from that in the original formation. The borehole temperature is far lower than the original formation temperature ne...

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Autores principales: Zhongxi Zhu, Chaofei Wang, Yuchen Ye, Wanneng Lei
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Lenguaje:EN
Publicado: Wiley 2021
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spelling oai:doaj.org-article:425748b925b8406899d045732bf5d7322021-12-02T05:24:30ZAnalysis of borehole stability in gas drilling using a thermal elastoplastic coupling model2050-050510.1002/ese3.992https://doaj.org/article/425748b925b8406899d045732bf5d7322021-12-01T00:00:00Zhttps://doi.org/10.1002/ese3.992https://doaj.org/toc/2050-0505Abstract Gas drilling causes lower pressure in the borehole and the Joule‐Thomson effect to occur at the bit nozzle, resulting in a temperature distribution in the borehole different from that in the original formation. The borehole temperature is far lower than the original formation temperature near the bottom of the borehole. This temperature difference leads to thermal stress on the borehole. The borehole temperature is higher than the formation temperature in the upper part of the borehole, causing the surrounding rock to expand because of the resulting thermal stress, which enhances the expansion of the surrounding rock into the borehole. The force supporting the borehole wall is thus weaker, and the borehole inevitably deforms under the original in situ stress. Meanwhile, the complete stress‐strain process of rock can be simplified into three linear stages: elasticity, plasticity, and residual. According to the combination of the Tresca yield criterion and the thermal stress, a thermal elastoplastic coupling model was developed to calculate the radii of the plastic softening and broken zones. An example calculation showed that the shrunken thermal stress at the bottom of the borehole could enhance the stability of the borehole wall, while the expansive thermal stress at the top could increase the instability of the borehole. When thermal stress was considered, the thermal elastoplastic model of rock was more consistent with the field measurements than when it was neglected.Zhongxi ZhuChaofei WangYuchen YeWanneng LeiWileyarticlecomplete stress‐strainelastoplastic couplinggas drillingplastic softeningstrengththermal stressTechnologyTScienceQENEnergy Science & Engineering, Vol 9, Iss 12, Pp 2388-2399 (2021)
institution DOAJ
collection DOAJ
language EN
topic complete stress‐strain
elastoplastic coupling
gas drilling
plastic softening
strength
thermal stress
Technology
T
Science
Q
spellingShingle complete stress‐strain
elastoplastic coupling
gas drilling
plastic softening
strength
thermal stress
Technology
T
Science
Q
Zhongxi Zhu
Chaofei Wang
Yuchen Ye
Wanneng Lei
Analysis of borehole stability in gas drilling using a thermal elastoplastic coupling model
description Abstract Gas drilling causes lower pressure in the borehole and the Joule‐Thomson effect to occur at the bit nozzle, resulting in a temperature distribution in the borehole different from that in the original formation. The borehole temperature is far lower than the original formation temperature near the bottom of the borehole. This temperature difference leads to thermal stress on the borehole. The borehole temperature is higher than the formation temperature in the upper part of the borehole, causing the surrounding rock to expand because of the resulting thermal stress, which enhances the expansion of the surrounding rock into the borehole. The force supporting the borehole wall is thus weaker, and the borehole inevitably deforms under the original in situ stress. Meanwhile, the complete stress‐strain process of rock can be simplified into three linear stages: elasticity, plasticity, and residual. According to the combination of the Tresca yield criterion and the thermal stress, a thermal elastoplastic coupling model was developed to calculate the radii of the plastic softening and broken zones. An example calculation showed that the shrunken thermal stress at the bottom of the borehole could enhance the stability of the borehole wall, while the expansive thermal stress at the top could increase the instability of the borehole. When thermal stress was considered, the thermal elastoplastic model of rock was more consistent with the field measurements than when it was neglected.
format article
author Zhongxi Zhu
Chaofei Wang
Yuchen Ye
Wanneng Lei
author_facet Zhongxi Zhu
Chaofei Wang
Yuchen Ye
Wanneng Lei
author_sort Zhongxi Zhu
title Analysis of borehole stability in gas drilling using a thermal elastoplastic coupling model
title_short Analysis of borehole stability in gas drilling using a thermal elastoplastic coupling model
title_full Analysis of borehole stability in gas drilling using a thermal elastoplastic coupling model
title_fullStr Analysis of borehole stability in gas drilling using a thermal elastoplastic coupling model
title_full_unstemmed Analysis of borehole stability in gas drilling using a thermal elastoplastic coupling model
title_sort analysis of borehole stability in gas drilling using a thermal elastoplastic coupling model
publisher Wiley
publishDate 2021
url https://doaj.org/article/425748b925b8406899d045732bf5d732
work_keys_str_mv AT zhongxizhu analysisofboreholestabilityingasdrillingusingathermalelastoplasticcouplingmodel
AT chaofeiwang analysisofboreholestabilityingasdrillingusingathermalelastoplasticcouplingmodel
AT yuchenye analysisofboreholestabilityingasdrillingusingathermalelastoplasticcouplingmodel
AT wannenglei analysisofboreholestabilityingasdrillingusingathermalelastoplasticcouplingmodel
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