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Mathematical Problems in Engineering
Volume 2016 (2016), Article ID 4052483, 12 pages
http://dx.doi.org/10.1155/2016/4052483
Research Article

Finite Element Optimised Back Analysis of In Situ Stress Field and Stability Analysis of Shaft Wall in the Underground Gas Storage

1College of Mechanical and Electronic Engineering, China University of Petroleum, Qingdao 266580, China
2College of Storage and Transportation and Architectural Engineering, China University of Petroleum, Qingdao 266580, China

Received 14 August 2015; Revised 11 January 2016; Accepted 13 January 2016

Academic Editor: Masoud Hajarian

Copyright © 2016 Yifei Yan et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

A novel optimised back analysis method is proposed in this paper. The in situ stress field of an underground gas storage (UGS) reservoir in a Turkey salt cavern is analysed by the basic theory of elastic mechanics. A finite element method is implemented to optimise and approximate the objective function by systematically adjusting boundary loads. Optimising calculation is performed based on a novel method to reduce the error between measurement and calculation as much as possible. Compared with common back analysis methods such as regression method, the method proposed can further improve the calculation precision. By constructing a large circular geometric model, the effect of stress concentration is eliminated and a minimum difference between computed and measured stress can be guaranteed in the rectangular objective region. The efficiency of the proposed method is investigated and confirmed by its capability on restoring in situ stress field, which agrees well with experimental results. The characteristics of stress distribution of chosen UGS wells are obtained based on the back analysis results and by applying the corresponding fracture criterion, the shaft walls are proven safe.