Submarine pipeline

About: Submarine pipeline is a research topic. Over the lifetime, 2635 publications have been published within this topic receiving 21300 citations.

Numerical Model for Local Scour under Offshore Pipelines

Abstract: A numerical model, based on potential-flow theory is proposed for simulating the equilibrium scour hole formed by unidirectional flow underneath offshore pipelines. The model employs a finite-difference method to solve the Laplace equation in terms of velocity potential in a curvilinear coordinate system. A boundary adjustment technique based on the Newton-Raphson method is used to calculate the free boundary formed by the eroded seabed by means of the equilibrium of all forces acting on a sediment particle on a sloping bed. Because the solution of flow field and adjustment of the seabed topography are carried out in an iterative manner, the model takes into account the interactions between the flow, pipe, and the seabed. The comparison of the present model with empirical formulas on the prediction of the maximum scour depth indicates that the present model is useful for approximate estimation of scour depth at a pipeline on the seabed for the case of clear-water scour.

Pipelines and risers

Abstract: Marine pipelines have become a safe and reliable part of the expanding infrastructure put in place for the transportation of oil and gas. Recent developments in research and engineering and new design codes have created the need for a book to educate pipeline engineers and provide materials for on-job training. This book has been written for engineers who work on pipelines, risers and piping, and is also intended as a textbook for graduate students and a reference for researchers. The book can also be used for design of offshore structures since it mainly addresses applied mechanics and design/engineering. Individual chapters address: wall-thickness and material grade selection; buckling collapse of deepwater metallic pipes; limit-state based strength design; soil and pipe interaction; hydrodynamics around pipes; finite element analysis of in-situ behavior; on-bottom stability; vortex-induced vibrations and fatigue; force model and wave fatigue; trawl impact, pullover and hooking loads; installation design; reliability-based strength design of pipelines; remaining strength of corroded pipes; residual strength of dented pipes with cracks; risk analysis applied to subsea pipeline engineering; route optimization, tie-in and protection; pipeline inspection, maintenance and repair; use of high strength steel; design of deepwater risers; design codes and criteria for risers; fatigue of risers; piping systems; pipe-in-pipe and bundle systems; life cycle cost modeling as a decision making tool in pipeline design; and design examples.

Submarine Paleoseismology Based on Turbidite Records

Abstract: Many of the largest earthquakes are generated at subduction zones or other plate boundary fault systems near enough to the coast that marine environments may record evidence of them. During and shortly after large earthquakes in the coastal and marine environments, a spectrum of evidence may be left behind, mirroring onshore paleoseismic evidence. Shaking or displacement of the seafloor can trigger processes such as turbidity currents, submarine landslides, tsunami (which may be recorded both onshore and offshore), and soft-sediment deformation. Marine sites may also share evidence of fault scarps, colluvial wedges, offset features, and liquefaction or fluid expulsion with their onshore counterparts. This article reviews the use of submarine turbidite deposits for paleoseismology, focuses on the dating and correlation techniques used to establish stratigraphic continuity of marine deposits, and outlines criteria for distinguishing earthquake deposits and the strategies used to acquire suitable samples and data for marine paleoseismology.

Chapter 25 The Significance of Contourites for Submarine Slope Stability

Abstract: Publisher Summary This chapter discusses the significance of contourites for submarine slope stability. It also provides an overview of environments where the stability of the slope is affected by the distribution and properties of contouritic sediments. Slope instabilities in areas of contouritic deposits are identified on continental slopes, on rises, and in ocean gateways, including some of the largest submarine landslides known. Thermohaline and geostrophic circulation affect surface-water masses, so that the continental shelf and the upper continental slope may also be influenced by the action of bottom currents, such as offshore Norway and eastern Canada. The changes in geostrophic and thermohaline currents may also induce the necessary conditions for gas–hydrate dissociation and slope instability. Contourites are deposited on the continental slope during both times of low-stand (glacials) and of high-stand (interglacials) of the sea level. The chapter also discusses the affect of contouritic sediments on the stability of submarine slopes. The submarine slope instability in muddy contourite drifts on northern, high-latitude slopes, of elongated drift mounds on southern high-latitude continental slopes and rises and in sediment drifts in areas of ocean gateways are also addressed.