Open Access

ARTICLE

Integrity and Failure Analysis of Cement Sheath Subjected to Coalbed Methane Fracturing

Lingyun Zhao^1,2, Heng Yang^3,4,*, Yuanlong Wei^1,2,*, Yuhuan Bu^3,4, Shaorui Jing^3,4, Peiming Zhou^1,2
1 Key Laboratory of Unconventional Natural Gas Evaluation and Development in Complex Tectonic Areas, Ministry of Natural Resources, Guiyang, 550081, China
2 Guizhou Engineering Research Institute of Oil & Gas Exploration and Development, Guiyang, 550081, China
3 School of Petroleum Engineering, China University of Petroleum (East China), Qingdao, 266580, China
4 Shandong Key Laboratory of Oilfield Chemistry, Key Laboratory of Unconventional Oil & Gas Development, China University of Petroleum (East China), Qingdao, 266580, China
* Corresponding Authors: Heng Yang. Email: ; Yuanlong Wei. Email:
(This article belongs to this Special Issue: Dynamics and Materials Processing in Petroleum Engineering)

Fluid Dynamics & Materials Processing 2023, 19(2), 329-344. https://doi.org/10.32604/fdmp.2022.020216

Received 11 November 2021; Accepted 28 February 2022; Issue published 29 August 2022

Abstract

Perforation and fracturing are typically associated with the development of coalbed methane wells. As the cement sheath is prone to failure during this process, in this work, the effects of the casing pressure, elastic modulus of the cement, elastic modulus of the formation, and casing eccentricity on the resulting stresses are analyzed in the frame of a finite element method. Subsequently, sensitivity response curves of the cement sheath stress are plotted by normalizing all factors. The results show that the maximum circumferential stress and Mises stress of the cement sheath increase with the casing internal pressure, elastic modulus of the cement and casing eccentricity. As the elastic modulus of the formation increases, the maximum circumferential stress of the cement sheath decreases, and its maximum Mises stress increases slightly. The cement sheath undergoes tensile failure during coalbed methane fracturing. The stress sensitivity of the cement sheath to the influential parameters is in the following order: casing internal pressure > elastic modulus of cement sheath > casing eccentricity > elastic modulus of formation.

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Graphical Abstract

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Keywords

Coalbed methane fracturing; finite element method; cement sheath integrity; sensitivity analysis; failure analysis

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