Residual strength of corroded subsea pipelines subject to combined internal pressure and bending moment

Abstract

Subsea pipelines used for oil and gas production in deepwater are exposed to harsh environment involving corrosion, high internal pressure, high temperature, and bending moment. Failure of subsea pipelines can cause serious problems, including oil/gas spill, hydrocarbon explosion and fires, production downtime, and maintenance and repair. Hence, it is of paramount importance to prevent failure of subsea pipelines. The aim of the present study is to investigate the residual strength characteristics of corroded subsea pipelines under combined internal pressure and bending moment. ANSYS nonlinear finite element method was applied to examine the residual strength characteristics of subsea pipelines by varying the corrosion damage and the loading ratio of internal pressure and bending moment, where the size of the corrosion damage was also varied. The ultimate strength interaction relationships of subsea pipelines between the internal pressure and bending moment with various corrosion damages were also developed. Finally, the insights and conclusions of the present study were summarised.

Experimental and numerical study on ultimate strength of steel tubular members with pitting corrosion damage

“…Experimental and numerical studies were performed to understand the behaviour of tubular members with artificially introduced localized pitting or patch-type corrosion, which are applied in steel lined pipes [10,11] and tubular members for offshore structures [12,13]. Recent experimental research into the effect of pitting corrosion artificially drilled on the local region of tubular members for offshore platforms [14] showed that aside from the compressive strength, pitting corrosion affects the structural failure mode in the pattern of local buckling.…”

Residual ultimate strength of offshore metallic pipelines with structural damage – a literature review

“…Considerable research such as Yeh and Kyriakides (1986), Yeh and Kyriakides (1988), Park and Kyriakides (1996), Vitali et al (2005) and Mohd et al (2015) has been conducted on the residual ultimate strength of offshore metallic pipelines. Critical parameters that would affect the pipeline strength include the diameter-to-thickness ratios (D/t), length-to-diameter ratios (L/D), material properties, load conditions, manufacturing processes, initial imperfections and residual stress.…”

A numerical study on water wetting associated with the internal corrosion of oil pipelines

“…Whereas, an incorrect prediction of water distribution leads to significant mistakes in predicting the corrosion rate. Moreover, selecting an appropriate type of inhibitor and estimating the required amount of inhibitor and corrosion resistant materials require a prior knowledge of water distribution inside the pipe (Niborg, 2005;Nesic, 2007;Cai et al, 2012;IIman and Kusmono, 2014;Mohd et al, 2015;Papavinasam et al, 2010).…”