Coupled lateral and axial soil-pipe interaction and lateral buckling Part II: Solutions

An Overview of Flow Assurance Heat Management Systems in Subsea Flowlines

“…The buried flowlines have a better heat capacity than a PIP system with an extended cooldown time [49] while the installation cost for buried insulated flowlines is roughly 35-50% higher than that of a PIP technique [49,101,102]. Throughout shutdown time, buried flowlines provide four times higher retention capacity for heat than the PIP systems [50,103,104]. Some other benefits of flowlines burial system include more option on installation vessels and contractors, more options on the vendor for the fabrication of flowline, when compared to PIP system gives a slower cooldown time during shutdown and a likelihood of single flowline repair [49], and also provide a reduced time and enhanced schedule for first oil [49].…”

“…Therefore, a buried insulated flowline has a greater heat capacity than a PIP system with extended cooldown time [49] while the installation cost of a buried insulated flowline is roughly 35-50% higher than that of a PIP technique [49,101,102]. In the course of the shutdown time before the advent of hydrates nucleation or gelling of wax, a buried flowline has four times higher retention capacity for heat than a PIP system [50,103,104]. This can be an important reduction in the overall project for long flowline systems [49].…”

Lateral buckling of submarine pipelines under high temperature and high pressure—A literature review

“…However, the ends of an overall pipeline are free to expand in practice. As seen in Figure 3, the pipe ends can generally expand freely (to some extent) through lowfriction mechanical sliders, named Pipeline End Manifolds (PLEM) (Jayson et al, 2008;Van den Abeele et al, 2015;Chee et al, 2018;Konuk, 2018). Under these circumstances, the effective axial force at pipe ends without constraints is equal to zero.…”

“…Between the anchor zones and the buckled regions (within segments AB and CD in Figure 4), the axial force switches between these two values and the pipe may slip, so that longitudinal boundary conditions (zero axial displacements and strains during buckling) must be consistently applied at the anchor points. (Konuk, 2018) In light of all these factors, the length of a pipeline during lateral buckling analysis can be either simply selected as the length of a given localized buckle between two virtual anchor points, or as the entire pipe length including multiple buckles. In this section, only a short pipe segment is considered with a unique buckle.…”

“…For a pipe resting on the seabed, axial compression is prevalent due to HT/HP. Among other things, the temperature distribution along a pipeline usually takes hours or days to reach a steady state after the products start to run through it (Alves et al, 2012;Konuk, 2018). The structural responses such as lateral buckling, upheaval buckling and pipe walking are induced accordingly (DNV, 2017a).…”