Mechanism of Casing Ovality Deformation in Deep Shale Gas Wells during Hydraulic Fracturing

Pan Fang; Maojun  Li; Haibo Zheng; Yutian Han; Hui Feng; Yongjun Hou

doi:10.62051/ijmee.v8n3.09

Authors

Pan Fang
Maojun Li
Haibo Zheng
Yutian Han
Hui Feng
Yongjun Hou

DOI:

https://doi.org/10.62051/ijmee.v8n3.09

Keywords:

Shale Gas Reservoirs, Casing Deformation, Shale Swelling, Cementing Quality, Compressive Deformation

Abstract

Casing deformation is a major constraint in the efficient development of shale gas horizontal wells during hydraulic fracturing. This study investigates the deformation characteristics and influencing factors in shale gas wells of the Zigong block. A finite element model of the shale–cement sheath–casing system for deep shale gas wells was established based on shale swelling mechanics. Through numerical simulations, the mechanism of casing deformation induced by shale swelling during hydraulic fracturing was determined, and the casing deformation patterns under the combined effects of shale swelling and cementing quality were revealed. Results show that shale swelling significantly increases casing compressive stress and can induce severe deformation. The casing stress distribution along the wellbore axis is strongly affected by the extent of shale hydration. In addition, cement sheath voids and elliptical geometry significantly affect casing stress. Elliptical cement sheaths exacerbate casing elliptical deformation, while cement sheath voids cause localized outward bulging of the casing. The orientation of cementing defects influences the casing's stress and deformation extent. Based on these findings, targeted strategies are proposed to mitigate deformation risks. This study provides new insights into casing failure mechanisms and offers theoretical guidance for fracture design and well integrity management in shale gas reservoirs.

References

[1] Zhao, L., X. Qin, J. Zhang, X. Liu, D. Han, J. Geng, and Y. Xiong. 2018. An Effective Reservoir Parameter for Seismic Characterization of Organic Shale Reservoir. Surveys in Geophysics 39(3): 509–541. doi: 10.1007/s10712-017-9456-9.

[2] Ma, X., and J. Xie. 2018. The Progress and Prospects of Shale Gas Exploration and Development in Southern Sichuan Basin, SW China. Petroleum Exploration and Development 45(1): 172–182. doi: 10.1016/s1876-3804(18) 30018-1.

[3] Yin, A., J. Li, W. Lian, and H. Zhang. 2025. Research progress on the mechanisms and control methods of casing deformation in shale gas horizontal wells. Xinjiang Oil & Gas 21(01):50-60. doi: 10.12388/j.issn.1673-2677.2025. 01. 006.

[4] Dong, K., N. Liu, Z. Chen, R. Huang, J. Ding, and G. Niu. 2019. Geomechanical analysis on casing deformation in Longmaxi shale formation. Journal of Petroleum Science and Engineering, 177: 724–733. doi: 10.1016/j.petrol. 2019. 02.068.

[5] Zhang, P., Y. He, Z. Liu, H. Tong, C. Deng, X. Ren, H. Zhang, et al. 2021. Shear Compression Deformation Test and Deformation Prevention Practice of Casing in Shale Gas Horizontal Wells. Natural Gas Industry B 8(5): 514–522. doi: 10.1016/j.ngib.2021.08.008.

[6] Guo, X., Li, J., Liu, G., Xi, Y., Zeng, Y., He, M., and Yan, H. (2019). Numerical simulation of casing deformation during volume fracturing of horizontal shale gas wells. Journal of Petroleum Science and Engineering, 172, 731–742. doi: 10.1016/j.petrol.2018.08.067.

[7] Yin, F., L. Han, S. Yang, Y. Deng, Y. He, and X. Wu. 2018. Casing deformation from fracture slip in hydraulic fracturing. Journal of Petroleum Science and Engineering 166: 235-241. doi: 10.1016/j.petrol.2018.03.010.

[8] Zhang, F., Z. Jiang, Z. Chen, Z. Yin, and J. Tang. 2020. Hydraulic Fracturing Induced Fault Slip and Casing Shear in Sichuan Basin: A Multi-Scale Numerical Investigation. Journal of Petroleum Science and Engineering 195: 107797. doi: 10.1016/j.petrol.2020.107797.

[9] Yan, W., L. Zou, H. Li, J. Deng, H. Ge, and H. Wang. 2017. Investigation of Casing Deformation during Hydraulic Fracturing in High Geo-Stress Shale Gas Play. Journal of Petroleum Science and Engineering 150: 22–29. doi: 10.1016/j.petrol.2016.11.007.

[10] Xi, Y., J. Li, G. Liu, C. Cha, and Y. Fu. 2018. Numerical Investigation for Different Casing Deformation Reasons in Weiyuan-Changning Shale Gas Field during Multistage Hydraulic Fracturing. Journal of Petroleum Science and Engineering 163: 691–702. doi: 10.1016/j.petrol.2017.11.020.

[11] Lian, Z., Yu, H., Lin, T., & Guo, J. 2015. A study on casing deformation failure during multi-stage hydraulic fracturing for the stimulated reservoir volume of horizontal shale wells. Journal of Natural Gas Science and Engineering, 23, 538-546. doi: 10.1016/j.jngse.2015.02.028

[12] Yu, H., Lian, Z., & Lin, T. 2014. Finite element analysis of failure mechanism of casing during shale gas fracturing. China Petroleum Machinery, 42(8), 84-88.

[13] Zhang, X., J. Liu, W. Cheng, W. Jiang, J. Jin, and L. Shen. 2022. New Type of Casing Deformation Rising in Weiyuan Changning Shale Gas Play. In International Petroleum Technology Conference. Riyadh, Saudi Arabia: IPTC. doi: 10.2523/iptc-22679-ea.

[14] Liu, K., D. Gao, Y. Wang, and Y. Liu. 2016. Effects of local load on shale gas well casing deformation. Nat. Gas Ind 36: 76-82. doi: 10.3787/j.issn.1000-0976.2016.11.010.

[15] Yin, F., B. Shi, G. Huang, and X. Wu. 2023. Integrity Assessment Methodology of Casing Ovality Deformation in Shale Gas Wells. Geoenergy Science and Engineering 224: 211643. doi: 10.1016/j.geoen.2023.211643.

[16] Skomedal, E., J. Park, D.V. Huynh, and J.C. Choi. 2019. Formation Induced Well Deformation. In SPE Europec Featured at 81st EAGE Conference and Exhibition. London, England, UK: SPE. doi: 10.2118/195475-ms.

[17] Liu, X., W. Zeng, L. Liang, and J. Xiong. 2016. Experimental Study on Hydration Damage Mechanism of Shale from the Longmaxi Formation in Southern Sichuan Basin, China. Petroleum 2(1): 54–60. doi: 10.1016/j. petlm. 2016.01.002.

[18] Wang, Y., X. Liu, L. Liang, and J. Xiong. 2020. Experimental Study on the Damage of Organic-Rich Shale during Water-Shale Interaction. Journal of Natural Gas Science and Engineering 74: 103103. doi: 10.1016/j.jngse. 2019. 103103.

[19] LI, G., Z. LI, S. HU, M. LI, and Z. LI. 2024. Shale-liquid interaction and its effect on in-situ stress. Journal of Southwest Petroleum University (Science & Technology Edition), 46(05): 115-123. doi: 10.11885/j.issn.1674-5086.2022.06.29.01.

[20] Gao, S., Z. Hu, W. Guo, L. Zuo, and R. Shen. 2013. Water absorption characteristics of gas shale and the fracturing fluid flowback capacity. Nat. Gas Ind, 33(12): 71-76. doi:10.3787/j.issn.1000-0976.2013.12.010.

[21] Meng, M., H. Ge, Y. Shen, Q. Hu, L. Li, Z. Gao, T. Tian, and J. Chao. 2020. The Effect of Clay-Swelling Induced Cracks on Imbibition Behavior of Marine Shale Reservoirs. Journal of Natural Gas Science and Engineering 83: 103525. doi: 10.1016/j.jngse.2020.103525.

[22] Li, G., Z. Li, and Z. Jiang, H. Yu, L. He. 2021. A study on the effect of shale-liquid reaction on casing deformation. Journal of Southwest Petroleum University (Natural Science Edition) 43(01): 103-10. doi: 10.11885/j.issn.1674-5086.2019.12.23.01.

[23] Zhang, R., B. Zhang, L. Cao, N. Lu, Y. Xu, L. Wu, S. Wang, and R. Jiang. 2024. Evaluation of the Casing Strength Reliability in Deep Gas Well by Taking into Account the Cement Quality and Strength Uncertainty: Method, Analysis and Application. Geoenergy Science and Engineering 234: 212623. doi: 10.1016/j.geoen.2023.212623.

[24] Zhu, M., N. Liu, X. Chen, Y. Zou, G. Li, Z. Zhang, and R. Wang. 2024. Numerical Analysis for Mechanical Integrity of Oval Shape Wellbore in Creep Formation. In 58th U.S. Rock Mechanics/Geomechanics Symposium. Golden, Colorado, USA: ARMA. doi: 10.56952/arma-2024-0335.

[25] Gu, C., X. Li, Y. Feng, J. Deng, and K. Gray. 2022. Numerical Investigation of Cement Interface Debonding in Deviated Shale Gas Wells Considering Casing Eccentricity and Residual Drilling Fluid. International Journal of Rock Mechanics and Mining Sciences 158: 105197. doi: 10.1016/j.ijrmms.2022.105197.

[26] Li, Z., G. Li, H. Li, J. Liu, Z. Jiang, and F. (Bill) Zeng. 2023. Effects of Shale Swelling on Shale Mechanics during Shale–Liquid Interaction. Energy 279: 128098. doi: 10.1016/j.energy.2023.128098.

[27] Li, G., Z. Li, and Z. Jiang, H. Yu, L. He. 2021. Study on the Mechanism of Shale Expansion on Casing Deformation in Weirong Field. Chinese Journal of Underground Space and Engineering 17(6): 2007-2014. doi:10.3969/j. issn. 1673-0836.2021.6. dxkj202106038.

[28] Li, H., Z. Li, G. Li, H. Yu, Z. Jiang, L. He, B. Guo, and M. Dong. 2020. Casing deformation mechanisms of horizontal wells in Weirong shale gas field during multistage hydraulic fracturing. Journal of Natural Gas Science and Engineering 84: 103646. doi: 10.1016/j.jngse.2020.103646.

[29] Teng, X., M. Chen, Y. Jin, Y. Lu, & Y. Xia. 2017. Poroelastic dynamics mechanisms of wellbore instability in tight formations. Petroleum Science Bulletin, 2(4), 478-489.

[30] Mises, R. V. (1913). Mechanik der festen Körper im plastisch-deformablen Zustand. Nachrichten von der Gesellschaft der Wissenschaften zu Göttingen, Mathematisch-Physikalische Klasse, 1913, 582-592.

[31] Liu, H., H. Sun, S. Cui, S. Wang, and S. Du. 2023. Study on the deformation mechanism and mechanical properties of bedding shale. Chinese Journal of Underground Space and Engineering 19: 174-180.