Thermal design of multi-layered composite pipelines for deep water oil and gas production

This paper addresses the technological challenges in the thermal design of multi-layer composite pipelines for offshore production of oil and gas in deep waters. An overview is provided for the flow assurance requirements, the thermal insulation systems and active heating of pipelines. A basic framework of thermal design is presented that consists of steady-state and transient heat-transfer analysis of multi-layered composite pipelines. Under some simplifying hypotheses, the thermal profile of the produced fluid along the pipeline is given by an analytical solution. Transient heat-transfer during a cold-down of a typical pipeline for deep water oil and gas production is simulated by numerical solution of conjugate heat-transfer in the solid and energy transport in the fluid.Indisponível

Thick-walled composite tubes for offshore applications : an example of stress and failure analysis for filament-wound multi-layered pipes

Acknowledgements Financial support of the part of this research by The Royal Society, The Royal Academy of Engineering, and The Carnegie Trust for the Universities of Scotland is gratefully acknowledged.Peer reviewedPostprin

Optimal control of the heave motion of marine cable subsea-unit systems

One of the key problems associated with subsea operations involving tethered subsea units is the motions of support vessels on the ocean surface which can be transmitted to the subsea unit through the cable and increase the tension. In this paper, a theoretical approach for heave compensation is developed. After proper modelling of each element of the system, which includes the cable/subsea-unit, the onboard winch, control theory is applied to design an optimal control law. Numerical simulations are carried out, and it is found that the proposed active control scheme appears to be a promising solution to the problem of heave compensation

On the structural mechanics of multi-layered subsea pipelines

During the 1990s the world-wide offshore industry has been increasingly developing oil and gas fields in deep water - classified here as generally above 300 metres (984 feet) water depth - often combined with production from reservoirs at higher temperatures. Subsea pipelines form an essential element of these developments and one of the limitations on deep water development has been the inability to provide large diameter conventional steel pipelines and risers capable of withstanding large external hydrostatic pressures. The work presented in this thesis investigates the performance of multi-layered pipe cross-sections for the required increase in hydrostatic pressure capacity and thermal insulation for such subsea pipelines. A fundamental investigation into the structural mechanics of such multi-layered pipes is presented with an emphasis on three principal issues - The mechanics of multi-layered pipe loading due to internal pressure, its collapse due to external pressure, and the behaviour of such pipe geometry when in a free submerged catenary configuration. Initially, the stresses induced by internal pressure have been investigated based on the Lame's equations. The results were compared with a finite element analysis and demonstrated good agreement. The stress distribution due to internal pressure was then investigated for a wide range of multi-layered pipe geometries and Young's Moduli of the core material. Comparisons are also presented with the stresses within equivalent single walled pipes. The much more complex external pressure problem was then addressed. The stability of a cylindrical multi-layered shell is a complex problem and in response to this, the investigation presented in this thesis followed a staged approach. Based on the previous work of Raville (1955), an elastic classic model was developed. Following this, using the concept of an elastic foundation, a new formulation was developed to derive critical external pressure loads. This work has been compared to that of Montague (1975) for critical external pressure based on two dimensional elastic plastic deformations up to maximum shear stress or Tresca failure theory. In addition, another approach for the elastic plastic model has been developed based on three dimensional Mises failure theory. A finite element analysis was then used to compare results from these different approaches for obtaining the critical external pressure. These four methods are used for a comparative investigation of collapse pressure predictions for a wide range of pipe geometries and Young's Moduli of the annular material. These comparisons give an indication of the applications of these methods and also give some insight into possible collapse mechanisms for multilayered pipes. This thesis also examines the performance of a multi-layered pipeline in an underwater catenary configuration and compares this to the performance of a single walled equivalent pipe. This was done by the development of an analytical catenary model aimed at optimising the catenary geometry around the two critical stress points of the catenary (the top connection at far position and touch down point at near position). The results demonstrated the significant improvement that multi-layered pipes could deliver for reductions in top tension and steel wall thickness when used in a catenary configuration. In overall terms, this work demonstrated that multi-layered subsea pipelines can provide a wide range of structural performance benefits both locally and globally. Locally, appropriate design and material selection can yield combinations of reduced steel volume and greater internal and external pressure capacity. In global terms, the buoyancy contribution from the thicker walls of multi-layered pipe will yield significant reductions in top tension when in a catenary configuration. This investigation has only examined a relatively narrow range of structural benefits of multi-layered pipes. Much further work needs to be done on local structural behaviour, internal layer bonds, on the internal damping of such pipes, and on the mechanics of the pipe segment connections

An overview of burst, buckling, durability and corrosion analysis of lightweight FRP composite pipes and their applicability

© 2019 Elsevier Ltd. All rights reserved.The main aim of this review article was to address the performance of filament wound fibre reinforced polymer (FRP) composite pipes and their critical properties, such as burst, buckling, durability and corrosion. The importance of process parameters concerning merits and demerits of the manufacturing methods was discussed for the better-quality performance. Burst analysis revealed that the winding angle of ±55° was observed to be optimum with minimum failure mechanisms, such as matrix cracking, whitening, leakage and fracture. The reduction of buckling effect was reported in case of lower hoop stress value in the hoop to axial stress ratio against axial, compression and torsion. A significant improvement in energy absorption was observed in the hybrid composite pipes with the effect of thermal treatment. However, the varying winding angle in FRP pipe fabrication was reported as an influencing factor affecting all the aforementioned properties. Almost 90% of the reviewed studies was done using E-glass/epoxy materials for the composite pipe production. By overcoming associated limitations, such as replacing synthetic materials, designing new material combinations and cost-benefit analysis, the production cost of the lightweight FRP composite pipes can be decreased for the real-time applications.Peer reviewe

Thick-walled composite tubes for offshore applications: an example of stress and failure analysis for filament-wound multi-layered pipes

The paper reviews practical applications of composite materials in oil and gas industry. A special consideration has been paid to possible future opportunities in offshore and onshore usage; in particular, to long fibre-reinforced composite pipes. The problem of thick-walled filament-wound multi-layered composite pipes subjected to outer pressure is considered as an example. An analytical method is used for failure analysis for different lay-ups and loading conditions. The stress distributions through the pipe thickness for various lay-ups are computed for fibre-reinforced pipes under different outer pressure magnitudes

Composites as enabling technology in flow assurance

In oil and gas production, flow assurance guarantees a successful and economical flow of the fluids from the reservoir to a designated processing facility. Flow assurance is one of the biggest challenges that a pipeline designer faces, especially under deep water where the temperature is low, and the pressure is high. These deep-water conditions favor the formation of solid deposits, which leads to blocking the flow line, reducing oil production, and potentially shutting down the well. To avoid this problem, the flow line temperature must always be kept above the solid deposit formation temperature. This necessitates accurate analysis of the thermal properties of pipelines in order to choose the best material suitable under these harsh conditions. This thesis provides a quantitative comparison based on thermal characteristics for flow assurance purposes. It also provides a realistic comparison based on strength requirement imposed on risers in general. First, we present a comparison between two different solutions (analytical and approximate) to predict the temperature profile in the steady state flow case. This comparison is carried on a steel pipeline under different cases, which are obtained by varying the length of the pipeline and the flow rate. Based on the results of the comparison, the solution that meets the objectives of this thesis is identified. Then, the thesis focuses on the effect of using different materials in the pipeline. The thesis presents another comparison between traditional steel catenary risers (SCR) and Composite Catenary Risers (CCR) based on their thermal characteristics for flow assurance purposes. The comparison is based on predicting the fluid flow temperature along the pipeline to show which material will keep the temperature above the solid deposit formation temperature, which is set in this thesis to be 20℃. Nominal homogenized mechanical and heat transfer properties are used for composite and steel pipelines of the same thickness and diameter. The obtained results show that composite risers have enhanced thermal characteristics over its counterpart steel pipelines. To establish rational comparisons between SCR and CCR, other aspects of their performance must be considered. Performance aspects regarding material strength, expected life and minimal weight design constitute the most essential minimal set for these comparisons. Comprehensive investigations are conducted, and conclusions are extracted to quantify overall performance aspects of SCR and CCR. All the code used to run the experiments was implemented in MATLAB

A Review Assessment of Fiber-Reinforced Polymers for Maritime Applications

Composite materials, comprised of fiber-reinforced polymer, offer a high strength-to-weight ratio, making them excellent for the building of complex, lightweight structures in a variety of industries, including the marine sector. There is an improvement in fuel efficiency and cost-effectiveness in general marine component developments as a result of the lightweight and flexible design characteristics. Fiber-reinforced polymer (FRP) composites are often used to construct boats, ships, and other marine compounds, such as the hull, column beams, piling structures, and other internal ship components, since they meet the aforementioned characteristics. In terms of durability, rigidity, and corrosion resistance, these FRPs may readily replace conventional metal counterparts.So,this review gives an overview of FRP Composites usage in marine industries for various potential application.Fiber-reinforced polymer composites offer a significant advantage in strength and weight when compared to conventional materials. Costs are declining and production times are slowly decreasing for maritime components because of their less weight and greater adaptability. &nbsp

Novel computational model for the failure analysis of composite pipes under bending

Tianyu Wang: Writing – review & editing, Writing – original draft, Visualization, Validation, Software, Investigation, Formal analysis, Data curation, Conceptualization. Oleksandr Menshykov: Writing – review & editing, Supervision, Project administration, Methodology, Conceptualization. Marina Menshykova: Writing – review & editing, Supervision, Project administration, Methodology, Conceptualization.Peer reviewe

Finite element modelling on the mechanical behaviour of Marine Bonded Composite Hose (MBCH) under burst and collapse

Currently, the properties of composites have been harnessed on pipelines in the marine offshore industry. In this study, Marine Bonded Composite Hose (MBCH) has been presented. It is aimed at understanding the stress/strain distribution on marine bonded hoses using local design pressure under burst and collapse cases. This study also investigates on composite material modelling, hose modelling, liner wrinkling, helical spring deformation and two MBCH models- with and without ovalisation. The ovalized model is considered the simplified model in this research. Mesh study was carried out on meshing the hose layers. In this study, local design pressure was considered and not operational pressure. This finite element model was adopted to predict the deformation and mechanical response behaviour of MBCH. From this study, composites could be considered to improve conventional marine hoses. The study findings include identification of buckled sections on the hose, and stressed zones on the helix reinforcement. Highly reinforced hose ends are recommended in ends of the MBCH as they had maximum stress and strain values