Open Access

ARTICLE

Uncertainty Analysis of the Residual Strength of Non-Uniformly Loaded Casings in Deep Wells

by Jingpeng Wang¹, Wei Zhang¹, Zhiwei Lin¹, Lin Song¹, Shiyuan Xie¹, Qi Liu², Wei Wang², Tao Yang², Kai Xu², Meng Li², Yuqiang Xu^3,*

1 PetroChina Xinjiang Oilfield Company, Karamay, 834000, China
2 School of Petroleum and Natural Gas Engineering, Chongqing University of Science and Technology, Chongqing, 401331, China
3 School of Petroleum Engineering, China University of Petroleum (East China), Qingdao, 266580, China

* Corresponding Author: Yuqiang Xu. Email:

(This article belongs to the Special Issue: Dynamics and Materials Processing in Petroleum Engineering)

Fluid Dynamics & Materials Processing 2023, 19(1), 105-116. https://doi.org/10.32604/fdmp.2023.020049

Received 31 October 2021; Accepted 20 December 2021; Issue published 02 August 2022

Abstract

An uncertainty analysis method is proposed for the assessment of the residual strength of a casing subjected to wear and non-uniform load in a deep well. The influence of casing residual stress, out-of-roundness and non-uniform load is considered. The distribution of multi-source parameters related to the residual anti extrusion strength and residual anti internal pressure strength of the casing after wear are determined using the probability theory. Considering the technical casing of X101 well in Xinjiang Oilfield as an example, it is shown that the randomness of casing wear depth, formation elastic modulus and formation Poisson’s ratio are the main factors that affect the uncertainty of residual strength. The wider the confidence interval is, the greater the uncertainty range is. Compared with the calculations resulting from the proposed uncertainty analysis method, the residual strength obtained by means of traditional single value calculation method is either larger or smaller, which leads to the conclusion that the residual strength should be considered in terms of a range of probabilities rather than a single value.

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Keywords

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