Effect of Casing Imperfection on the Casing Strength in Steam Injection Wells

International Conference of Applied Science and Technology for Infrastructure Engineering

土木建筑工程;材料科学

Hidayat, M.I.P.^1 ; Irawan, S.^2 ; Abdullah, M.Z.^2

Department of Materials and Metallurgical Engineering, Institut Teknologi Sepuluh Nopember, Kampus ITS Keputih Sukolilo, Surabaya

60111, Indonesia^1

Department of Petroleum Engineering, Universiti Teknologi PETRONAS, Bandar Seri Iskandar, Tronoh, Perak Darul Ridzuan

31750, Malaysia^2

关键词: Circumferential direction;    Collapse pressure;    Collapse strength;    Corrosion attack;    Formation pressure;    Severe Deformation;    Steam injection wells;    Thermal environment;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/267/1/012019/pdf
DOI  :  10.1088/1757-899X/267/1/012019

来源: IOP

【 摘 要 】

In this study, effect of casing imperfection on the casing strength in thermal environment of steam injection wells was investigated. The imperfections were modelled in the form of casing pits which may represent local cavitation, wear or corrosion attacks. Several pits with various depths (C) relative to the casing thickness (t) and different casing diameter to thickness (D/t) ratios were considered in this study. For the purpose of investigation, 3D FE models consisting of defective casing-cement-formation system were developed. N80 casing with the casing length of 3.048 m is analyzed in the numerical study. In the analysis, the combined effects of cyclic thermal stress (from 25 °C to 360 °C), collapse pressure (from formation) and defects on casing were taken into account. From the numerical study, it is found that the casing imperfection greatly affected the casing strength in steam injection wells. The presence of pits markedly reduces the casing collapse strength in comparison to that of non-defective casing. For instance, the collapse strength of casing having 2 pits along its circumferential direction with depth C = 0.5t reduced about 49% and 43% for D/t = 22.09 and D/t = 17.26, respectively. In addition, the combination of high temperature, imperfection factor and formation pressure induces severe deformation on casing, even at lower formation pressure.