Prediction method and distribution characteristics of in situ stress based on borehole deformation—A case study of coal measure stratum in Shizhuang block, Qinshui Basin
A geometric equation of borehole deformation under stress was deduced based on the basic theory of elasticity. Subsequently, we established the quantitative relationship between the in situ stress and geometrical parameters of borehole deformation. Furthermore, we proposed an in situ stress predicti...
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| Format: | Article |
| Language: | English |
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Frontiers Media S.A.
2022-08-01
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| Series: | Frontiers in Earth Science |
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| Online Access: | https://www.frontiersin.org/articles/10.3389/feart.2022.961311/full |
| _version_ | 1828148921569902592 |
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| author | Xinxin Fang Xinxin Fang Hong Feng Yunhong Wang Tao Fan |
| author_facet | Xinxin Fang Xinxin Fang Hong Feng Yunhong Wang Tao Fan |
| author_sort | Xinxin Fang |
| collection | DOAJ |
| description | A geometric equation of borehole deformation under stress was deduced based on the basic theory of elasticity. Subsequently, we established the quantitative relationship between the in situ stress and geometrical parameters of borehole deformation. Furthermore, we proposed an in situ stress prediction model based on borehole deformation. Additionally, numerical simulations of borehole morphology in different lithologies under in situ stress were conducted to analyze the deformation effect. Logging parameters that are sensitive to the shear wave time difference, such as longitudinal wave time difference, density, and natural gamma radiation, were selected for training using an artificial neural network (ANN) to predict the shear wave time difference. The results demonstrated that 1) combining the theoretical derivation and numerical simulation, the borehole geometry under stress was quasi-elliptic, and 2) compared with the existing shear wave time difference curve, the predicted geometry by the ANN was consistent with the actual geometry. Consequently, compared with the tested data from acoustic emission, the overall error of the in situ stress predicted using the new method was less than 9.2%. Moreover, the accuracy of the coal seam was the highest, wherein the average errors of the maximum and minimum horizontal principal stresses were 2.01 and 2.56%, respectively, which confirms the feasibility of the proposed method. |
| first_indexed | 2024-04-11T21:23:26Z |
| format | Article |
| id | doaj.art-d59ce0c04d214a4583082996cb223ab0 |
| institution | Directory Open Access Journal |
| issn | 2296-6463 |
| language | English |
| last_indexed | 2024-04-11T21:23:26Z |
| publishDate | 2022-08-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Earth Science |
| spelling | doaj.art-d59ce0c04d214a4583082996cb223ab02022-12-22T04:02:32ZengFrontiers Media S.A.Frontiers in Earth Science2296-64632022-08-011010.3389/feart.2022.961311961311Prediction method and distribution characteristics of in situ stress based on borehole deformation—A case study of coal measure stratum in Shizhuang block, Qinshui BasinXinxin Fang0Xinxin Fang1Hong Feng2Yunhong Wang3Tao Fan4China Coal Research Institute, Beijing, ChinaChina Coal Technology & Engineering Group Xi’an Institute, Xi’an, ChinaChina Coal Technology & Engineering Group Xi’an Institute, Xi’an, ChinaChina Coal Technology & Engineering Group Xi’an Institute, Xi’an, ChinaChina Coal Technology & Engineering Group Xi’an Institute, Xi’an, ChinaA geometric equation of borehole deformation under stress was deduced based on the basic theory of elasticity. Subsequently, we established the quantitative relationship between the in situ stress and geometrical parameters of borehole deformation. Furthermore, we proposed an in situ stress prediction model based on borehole deformation. Additionally, numerical simulations of borehole morphology in different lithologies under in situ stress were conducted to analyze the deformation effect. Logging parameters that are sensitive to the shear wave time difference, such as longitudinal wave time difference, density, and natural gamma radiation, were selected for training using an artificial neural network (ANN) to predict the shear wave time difference. The results demonstrated that 1) combining the theoretical derivation and numerical simulation, the borehole geometry under stress was quasi-elliptic, and 2) compared with the existing shear wave time difference curve, the predicted geometry by the ANN was consistent with the actual geometry. Consequently, compared with the tested data from acoustic emission, the overall error of the in situ stress predicted using the new method was less than 9.2%. Moreover, the accuracy of the coal seam was the highest, wherein the average errors of the maximum and minimum horizontal principal stresses were 2.01 and 2.56%, respectively, which confirms the feasibility of the proposed method.https://www.frontiersin.org/articles/10.3389/feart.2022.961311/fullin situ stressborehole deformationANNcoal measure stratumQinshui Basin |
| spellingShingle | Xinxin Fang Xinxin Fang Hong Feng Yunhong Wang Tao Fan Prediction method and distribution characteristics of in situ stress based on borehole deformation—A case study of coal measure stratum in Shizhuang block, Qinshui Basin Frontiers in Earth Science in situ stress borehole deformation ANN coal measure stratum Qinshui Basin |
| title | Prediction method and distribution characteristics of in situ stress based on borehole deformation—A case study of coal measure stratum in Shizhuang block, Qinshui Basin |
| title_full | Prediction method and distribution characteristics of in situ stress based on borehole deformation—A case study of coal measure stratum in Shizhuang block, Qinshui Basin |
| title_fullStr | Prediction method and distribution characteristics of in situ stress based on borehole deformation—A case study of coal measure stratum in Shizhuang block, Qinshui Basin |
| title_full_unstemmed | Prediction method and distribution characteristics of in situ stress based on borehole deformation—A case study of coal measure stratum in Shizhuang block, Qinshui Basin |
| title_short | Prediction method and distribution characteristics of in situ stress based on borehole deformation—A case study of coal measure stratum in Shizhuang block, Qinshui Basin |
| title_sort | prediction method and distribution characteristics of in situ stress based on borehole deformation a case study of coal measure stratum in shizhuang block qinshui basin |
| topic | in situ stress borehole deformation ANN coal measure stratum Qinshui Basin |
| url | https://www.frontiersin.org/articles/10.3389/feart.2022.961311/full |
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