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Summary A subsea blowout preventer (BOP) system is critical in providing safe working conditions for drilling activities in deepwater oil exploration. However, performance evaluation of the shear ram BOP is still a challenge for the industry. In this paper, two aspects of BOP shearing capability are studied: The required shear force to cut the pipe inside BOP successfully and the time it takes to shear the pipe and close the well. A finite element model is used to calculate the maximum shear force of a typical drillpipe, while an analytical hydraulic model is proposed to calculate the BOP closing time. A case study is presented for estimating the emergency disconnect sequence time in a deepwater offshore scenario. It is assumed that the BOP control system is activated from the surface, employing an electrohydraulic multiplexed control device for closing the BOP and rapidly disconnecting the lower marine riser package (LMRP), thus preventing damage to both riser and wellhead.

The latching control represents an attractive alternative to increase the power absorption of wave energy converters (WECs) by tuning the phase of oscillator velocity to the wave excitation phase. However, increasing the amplitude of motion of the floating body is not the only challenge to obtain a good performance of the WEC. It also depends on the efficiency of the power take-off system (PTO). This study aims to address the actual power performance and operation of a heaving point absorber with a direct mechanical drive PTO system controlled by latching. The PTO characteristics, such as the gear ratio, the flywheel inertia, and the electric generator, are analyzed in the WEC performance. Three cylindrical point absorbers are also considered in the present study. A wave-to-wire model is developed to simulate the coupled hydro-electro-mechanical system in regular waves. The wave energy converter (WEC) performance is analyzed using the potential linear theory but considering the viscous damping effect according to the Morison equation to avoid the overestimated responses of the linear theory near resonance when the latching control system is applied. The latching control system increases the mean power. However, the increase is not significant if the parameters that characterize the WEC provide a considerable mean power. The performance of the proposed mechanical power take-off depends on the gear ratio and flywheel. However, the gear ratio shows a more significant influence than the flywheel inertia. The operating range of the generator and the diameter/draft ratio of the buoy also influence the PTO performance.

The modelling of nonlinear viscous effects for a wave energy converter (WEC) under control systems represents a difficult task. The control system aims to maximize the power capture of WECs. Consequently, large velocities of these devices observe. In addition, the linear potential theory is unable to show a realistic prediction of power production by neglecting viscous effects. A common way of modelling the viscous drag force of WECs is based on the viscous term of the Morison equation. In the literature, this approach shows that drag coefficient has a high variability that depends mainly on the relative velocity of the device. In the paper, two models analyze the nonlinear viscous effects on three cylindrical point absorbers. They have different diameter (D) to draft (T) ratios and are controlled by latching control. The first model approaches the viscous force according to the Morison equation. The second model is a heuristic model proposed by the present study. This new approach calculates the viscous force based on two parameters. Computational fluid dynamics (CFD) evaluates the fidelity of both models and the power production of the three-point absorbers. The proposed model shows good concordance with the CFD results at low and high velocities of point absorbers. The power production of the three-point absorbers controlled by latching shows that the power conversion increase is proportional to the D/T ratio.

In recent years, the wind turbine market has gained relevance due to technological advances that make this renewable energy type increasingly efficient and economically competitive. Numerous studies have focused on the rotor blades due to their design process and constant increase in dimensions. During their useful life, the blades are exposed to critical external loads from winds, gravity, and dynamic interactions. In addition to having a high aerodynamic performance, these structures are made of composite materials to achieve a high strength-to-weight ratio. A fluid–structure interaction (FSI) simulation is required to analyze the complex aeroelastic phenomenon of wind pressure on the turbine blades. A more accurate structural response of the FSI behavior can be performed using shell elements in a finite element analysis based on the sectional beams’ mass and stiffness properties. In the present work, the geometric and material properties are determined from the mass and stiffness properties for a blade of the unsteady aerodynamics experiment (UAE) Phase VI wind turbine, tested by the National Renewable Energy Laboratory (NREL) in the NASA Ames wind tunnel. The application of a technique makes it possible to detail the thickness distribution, the number of the composite layers, and mechanical and physical properties of the material, relating it with the most relevant structural properties of the blade sections. This result can contribute to the more accurate calibration of FSI models for predicting structural behavior. The numerical models are correlated with the experimental test’s natural frequencies to ensure the attendance of the dynamic blade requirements.

Lower efficiencies induce higher energy costs and pose a barrier to wave energy devices’ commercial applications. Therefore, the efficiency enhancement of wave energy converters has received much attention in recent decades. The reported research presents the double snap-through mechanism applied to a hemispheric point absorber type wave energy converter (WEC) to improve the energy absorption performance. The double snap-through mechanism comprises four oblique springs mounted in an X-configuration. This provides the WEC with different dynamic stability behaviors depending on the particular geometric and physical parameters employed. The efficiency of these different WEC behaviors (linear, bistable, and tristable) was initially evaluated under the action of regular waves. The results for bistable or tristable responses indicated significant improvements in the WEC’s energy capture efficiency. Furthermore, the WEC frequency bandwidth was shown to be significantly enlarged when the tristable mode was in operation. However, the corresponding tristable trajectory showed intra-well behavior in the middle potential well, which induced a more severe low-energy absorption when a small wave amplitude acted on the WEC compared to when the bistable WEC was employed. Nevertheless, positive effects were observed when appropriate initial conditions were imposed. The results also showed that for bistable or tristable responses, a suitable spring stiffness may cause the buoy to oscillate in high energy modes.

Several latching control strategies have been proposed to improve the power performance of wave energy converters (WECs). However, the benefits and challenges vary for different WECs and PTO systems. This paper addresses the power performance of a specific direct mechanical-drive power take-off (DMDPTO) system considering the application of a non-predictive latching control. The WEC is a heaving point absorber (PA) that consists of a cylindrical buoy and a bottom-mounted support structure. A pulley converts the vertical motion of the buoy into rotational motion, and a freewheel system rectifies the rotation direction for the power generation. A speed multiplier amplifies the velocity delivered by the buoy to drive a flywheel, which is rigidly connected to the electrical generator. A time-domain model is developed to simulate the interaction of the wave-buoy-DMDPTO in each time interval calculating hydrodynamic and electro-mechanical forces. An exhaustive optimization strategy is applied to maximize power production, optimizing the DMDPTO parameters. The sensitivity of power production to the wave height and wave period are presented considering the generator’s operational limit. Additionally, the capture width ratio and peak-to-average power ratio are calculated for the controlled PA, and the results are compared to the control-free WEC and linear PTO systems.

The paper presents the development of a downscaled hardware-in-the-loop (HiL) setup for a wave energy converter heaving point absorber. HiL simulation involves the buoy motion coupled to a gearbox system that converts the buoy’s vertical movement into rotational. The dynamic movement of the heaving buoy is simulated and converted into rotation. A process is employed to determine the resultant torque based on the generator’s rotational speed. The use of an online derivative technique allows the system to implement an inertia emulation. Consequently, without modifying physical components, it is possible to change the system dimension. The demanded torque is then applied using an electric machine torque control loop. The technique is developed for real-time implementation and allows the reproduction of different wave conditions. Froude’s law is used to determine the scale down factor considering the machine limitations and the wave conditions. Experimental results validate the methodology.

Repair by welding is widely used in the shipbuilding industry during ship construction. The effect of the residual stress distribution induced by the welding process on the ship structure is important for the repair effectiveness. This article presents an experimental study of the residual stress distribution induced by repair welding in the plates that are typically used in ships and offshore structures. Different repair techniques are evaluated to identify the best practice associated with residual stress values. Recommendations for repair welding are discussed, and modifications to the present practice are proposed.

Due to the complexity of installations and connections of subsea production equipment and the massive structures involved in a challenging environment, the failure of subsea production equipment could induce enormous loss to the safety and reliability of structures in addition to the cost of the oilfield development. One of the challenges that the subsea production structures face, as it moves to ultra-deep water and polar underwater equipment, is to design subsea shell structures capable of withstanding high external pressures. Hence, a subsea function chamber (SFC) has been lately proposed as a viable solution, which has a high level of safety and reliability, and a technique for the subsea production system. This paper presents a general and efficient buckling and collapse analysis strategy. In this work, the SFC is composed of cylindrical and hemispherical shaped steel material. Initial imperfection-based nonlinear buckling analysis has been carried out to investigate the buckling and risks associated with different thicknesses of the structure. Linear and nonlinear static buckling analyses have been carried out using ABAQUS software. By introducing the nonlinear properties of materials, the nonlinear numerical model of SFC is established. The effects of the thickness of different models and the number of stiffeners on the buckling modes are discussed. The wall thickness is calculated by the Donnell equation and Timoshenko’s classical method. It has been found that the classical solutions given by the Donnell and Timoshenko equations are more accurate for structures with larger lengths and diam. The thickness and number of stiffeners have a great influence on the ultimate buckling external pressure load of SFC structure

The welding numerical simulation involves thermal and mechanical analyses and metallurgical consideration. The thermal analysis determines the transient temperature distribution on the welded part, and its accuracy is relevant for the following analyses on structural integrity, in particular buckling and fatigue failure modes of steel-plated structures. The temperature distribution is strongly influenced by the size and shape of the heat source, which can be represented as a double ellipsoid and defined by Goldak’s parameters. The main difficulty is that the adjustment of these parameters to obtain a suitable temperature distribution is usually determined by trial and error. In this paper, a parametric study is performed to analyze the influence of Goldak’s parameters on the weld bead size for 2D and 3D numerical welding simulations. A method to estimate the parameters of a double ellipsoidal heat source in motion is proposed. An algorithm has been implemented based on the combination of analytical formulation, experimental data, and numerical simulation. As an analytical formulation, the Fachinotti’s solution is used to determine the isotherms. The weld bead dimensions are defined from the melting temperature isotherm of the material. Experimental data, such as the welding process parameters and the weld bead dimensions are input to the algorithm. Numerical simulations of the welding process have been developed to calibrate and validate the method. The numerical simulation results from the obtained Goldak’s parameters by the proposed method are correlated with the experimental results of fillet-welded specimens.

This paper addresses the current status and future research and development perspectives associated with technologies to harness offshore renewable energy, including offshore wind, waves, tides, ocean currents, and thermal and salinity gradient, in South America (SA). It focuses on five countries: Argentina, Brazil, Chile, Colombia and Uruguay. At first, a comprehensive survey presents the number of scientific papers classified based on the resource to show the tendency and importance of such subjects in the academic community. Each country’s electricity matrix and grid connection are shown to understand the region’s renewable source participation situation. The potential of offshore renewable resources is addressed by considering the published technical papers in scientific journals. The main conflicts and synergies associated with ocean space utilization are presented by considering the exclusive economic zone of each country. The status of the regulatory frameworks to promote and development of offshore renewable energies is presented. Two sections are dedicated to presenting the active, decommissioned and planned projects, research groups and laboratory infrastructures to develop the technologies. The last section discusses the future perspectives on the development of this sector in SA. It is observed that SA, with more than 25,000 km of coastline, has a great potential for offshore renewable energy; however, so far, these resources have not been explored commercially. Larger investment in the sector, establishing an adequate legal framework and deploying full-scale demonstration projects at sea are necessary for the commercialization of such technologies in SA.

A study of the migration of the grain boundary misorientation and its relationship with the residual stresses through time immediately after the completion of a thermomechanical simulation has been carried out. After physically simulating an intercritically overheated welding heat affected zone, the variation of the misorientation of grain contours was observed with the electron backscatter diffraction (EBSD) technique and likewise the variation of the residual stresses of welding with RAYSTRESS equipment. It was observed that the misorientation of the grain contours in an ASTM DH36 steel was modified after the thermomechanical simulation, which corresponds to the measured residual stress variation along the first week of monitoring, with compressive residual stresses ranging from 195 MPa to 160 MPa. The changes in misorientation indicate that the stress relaxation phenomenon is associated with the evolution of the misorientation in the microstructure caused by the welding procedure. On the first day, there was a fraction of 4% of the kernel average misorientation (KAM) values at 1° misorientation and on the fourth day, there was a fraction of 7% of the KAM values at 1° misorientation.

Oil-and-gas field development projects are capital-intensive, and optimizing profitability has always been a critical subject for the industry. This paper presents a mixed-integer linear programming (MILP) model to facilitate scenario comparison and selection at the design stage for green offshore oil-field development. The model solves an allocation-scheduling problem with the objective of maximizing the project’s net present value (NPV). Decision variables include the drilling schedule for both production and injection wells, well assignment to FPSO (floating, production, storage and offloading unit), FPSO oil and water production capacity, and water injection capacity. The model represents the waterflood scheme through an injection-production relationship matrix, leading to consistent scheduling of producer-injector pairs. Also, the model allows the assignment of development priorities to blocks or well groups, which corresponds to the “phased-development” concept in real-world application. Methods to estimate production rates are proposed, and a production prediction model is established. Production rates considering scheduling effect are generated by a linear superposition of base production curves from reservoir simulations. Two synthetic reservoirs with properties resembling deepwater offshore Brazil illustrated the performance of the modeling approach. It is observed that in early development years, drilling capacity and oil production capacity are active constraints to the system, while in late development years, active constraints change to water capacity, which propels the “capacity expansion” concept in the late production years, such as subsea water separation. Higher recovery is obtained with expedited production, but NPV does not necessarily increase with increased oil recovery when there is considerable investment on extra FPSOs.

Thermal insulation is widely used in offshore oil production for flow assurance design. Research efforts have concentrated on the thermal and mechanical properties of the insulation material, but few publications have focused on the optimization of the insulation. For certain subsea production systems, several optional insulation materials are available. The distribution of insulation along a subsea system to fulfill thermal requirements is not unique to each insulation material. Manually defined insulation designs often lead to a conservative approach that consumes more material than necessary. To find the most economical design, an optimization method combined with machine learning techniques is presented. A subsea production system using different insulation materials is assessed in the case study and optimization results are discussed. Four different insulation materials are used, and 2000 models are simulated for each material to prepare the training data for the machine learning algorithm. The trained algorithm is able to predict the minimum temperature of the system with an error smaller than 5.5%. Genetic algorithm and particle swarm optimization are used to find the most efficient insulation distribution for each material. The optimized costs related to each insulation material are then compared. The results show that the proposed method is capable of defining material and thickness variations throughout the subsea system with the aim of reducing costs.

The subsea manifold as the hub oil and gas transportation equipment is a critical part for the layout optimization of subsea production system and reducing the number of pipelines. The traditional subsea manifold is fixed on seabed by its foundation, so traditional manifold system is hard to be discarded and recovered although it has many advantages and is applied widely in the deep water development scenario. In this paper, a new subsea suspended manifold concept is proposed to discuss its feasibility by the hydrodynamic performance state in vertical tension and catenary mooring methods. A mathematical model is established to solve the chain tension distribution and displacement of the subsea suspended manifold. Meanwhile, the motion response of the subsea suspended manifold under different influence factors, tension distribution of the mooring chains and the flexible jumpers in two mooring schemes are simulated, respectively, through OrcaFlex software. The research results will provide an important reference for the optimization of the preliminary scenario design of the subsea suspended manifold mooring system.

The growing increase of offshore wind implementations has been made this modality subject to many resource assessment works. However, the variety of available wind datasets and the difficulty of the validation process over the ocean still leave uncertainty about the most relevant data for offshore wind resource assessment and how much they affect the energy estimation. This study investigates the influence of ERA5, CFSv2, MERRA2 atmospheric reanalyses, and the WRF model on the offshore wind resource technical potential and cost estimation of offshore wind projects. The coastline of the Rio de Janeiro state of Brazil is considered as the focus of the study region. Wind results are validated with in-situ measurements from three meteo-oceanographic buoys by the SIMCosta and PNBOIA programs, an anemometer placed on a floating vessel for production storage and offloading (FPSO), and seven weather stations positioned inland near the coastline from the National Meteorological Institute of Brazil (INMET). Then, energy production and cost estimation are calculated employing the IEA-15 MW wind turbine, and the differences between the models are analyzed. The comparative analysis reveals significant differences in the annual energy production, mainly near to the coastline, impacting the cost estimation of the projects in the planning phase.

Sandwich pipes consisting of two concentric metal pipes with insulation material in annulus have been developed to meet challenging mechanical and thermal requirements of deep and ultra-deepwater oil and gas production. Passive thermal insulation is designed to meet flow assurance requirements under steady-state production conditions, but is unlikely to meet more severe conditions during transient events such as warm-up and cool-down. In this chapter, we present a sandwich pipe system with active electrical heating, provided by a number of electrical resistance strips stuck longitudinally over the outer surface of the inner metal pipe. A steady-state heat transfer analysis is carried out to determine the temperature distribution in a cross section of the sandwich pipe, the power requirement of electrical heating, and the overall heat transfer coefficient. It is shown that the sandwich pipe with active heating is a viable solution to meet severe flow assurance requirements of ultra-deepwater oil production.

In this chapter, a fluid-structural model for analyzing the dynamic behavior of riser vibration subjected to simultaneous internal gas–liquid two-phase flow and external marine current is proposed. Slug flow regime is considered as it causes most violent vibrations. An analytical model is adopted for the prediction of important flow characteristics of the vertical gas–liquid slug flow. A wake oscillator is employed to model the vortex shedding behind the riser. The dynamic behavior of risers is analytically and numerically investigated by using the generalized integral transform technique (GITT), by which the transverse vibration equation is transformed into a coupled system of second-order differential equations in time. Parametric studies are performed to analyze the effects of the superficial velocities of liquid and gas on the dynamic behavior of risers.

In this chapter, we first present a global heat balance analysis of typical pipelines for deepwater oil and gas production and show that active heating is necessary for long pipelines due to technical limitations of passive thermal insulation systems. Two methods of combined active heating and passive insulation are then considered. By the first method, active heating is provided by circulating hot water in the annulus between concentric pipes. Under certain simplifying hypotheses, we provide a closed-form analytical solution for the temperature profiles of the produced fluid and the circulating heat medium. By the second method, active heating is provided by electrical resistance on the inner steel pipe. For this case, we present a heating strategy that minimizes the power requirement for a given minimum temperature of produced fluid. Numerical results are shown for the second heating method. Significant reduction in power requirement is achieved.

Pipe–soil interaction has been intensively investigated both theoretically and experimentally due to its importance in the design of seabed pipelines. In recent years, the effects of single phase, steady internal flow on the dynamic response of seabed pipelines have received increasing attention. However, the effects of transient two-phase flow on the vibration behavior of seabed pipelines have been seldom studied. In this chapter, a physical model for analyzing the dynamic behavior of a seabed pipeline conveying gas–liquid two-phase flow is proposed. Slug flow regime is considered as it causes most violent vibrations. An analytical model is adopted for the prediction of important flow characteristics of the gas–liquid slug flow. The dynamic behavior of pipelines is analytically and numerically investigated by using the generalized integral transform technique (GITT), by which the transverse vibration equation is transformed into a coupled system of second-order differential equations in the temporal variable. Good convergence behavior of the proposed eigenfunction expansions is demonstrated for calculating the transverse displacement at various points of pipelines conveying gas–liquid slug flow. Parametric studies are performed to analyze the effect of the internal two-phase flow on the dynamic behavior of pipelines.

In this chapter, we review the generalized integral transform technique (GITT) approach adopted to analyze some typical structural dynamic problems. The Sect. 7.2 general solution methodology to solve the vibration problems is presented. Special topics and applications including the vibration of axially moving Euler beams, axially moving Timoshenko beams, pipes conveying fluid, pipes conveying gas–liquid two-phase flow, and axially moving orthotropic plates are presented.

Dynamic behavior of axially functionally graded (FG) pipes conveying fluid is investigated numerically by using the generalized integral transform technique (GITT). The transverse vibration equation is integral transformed into a coupled system of second-order differential equations in the temporal variable. The Mathematica’s built-in function, NDSolve, is employed to numerically solve the resulting transformed ODE system. Excellent convergence of the proposed eigenfunction expansions is demonstrated for calculating the transverse displacement at various points of axially FG pipes conveying fluid. The proposed approach iss verified by comparing the obtained results with the available solutions reported in the literature. Moreover, parametric studies are performed to analyze the effects of Young’s modulus variation, material distribution, and flow velocity on the dynamic behavior of axially FG pipes conveying fluid.

Sandwich pipes (SP) with steel tubes and a lightweight flexible core are under consideration as a potential solution for ultra-deepwater submarine pipelines, combining high structural resistance with thermal insulation. Besides polymeric materials, strain hardening cementitious composites (SHCC) reinforced with polyvinyl alcohol (PVA) fibers, a micromechanically designed material with high tensile ductility, can be an option for the annular material. The purpose of this chapter is to investigate experimentally and numerically the collapse behavior of SP filled with SHCC under external hydrostatic pressure. The preparation procedure for SHCC and the fabrication process for SP are presented in detail. The full-scale laboratorial tests of SP are performed using a hyperbaric chamber to analyze the collapse pressure subjected to external pressure. The mechanical behavior of SHCC is simulated using a concrete damaged plasticity (CDP) model provided by the commercial finite element package ABAQUS, whose parameters are estimated by tension and compression tests. In addition, a systematic parametric study is performed to analyze the effects of ovality, thickness, and outer/inner radius ratio on the collapse pressure of SP with SHCC core.

In this chapter, the dynamic behavior of pipes conveying gas–liquid two-phase flow is analytically and numerically investigated on the basis of the generalized integral transform technique (GITT). The use of the GITT approach in the analysis of the transverse vibration equation leads to a coupled system of second-order differential equations in dimensionless time. The Mathematica’s built-in function, NDSolve, is employed to numerically solve the resulting transformed ODE system. The characteristics of gas–liquid two-phase flow are represented by a slip-ratio factor model that was devised and used for similar problems. Good convergence behavior of the proposed eigenfunction expansions is demonstrated for calculating the transverse displacement at various points of pipes conveying air–water two-phase flow. Parametric studies are performed to analyze the effects of the volumetric gas fraction and the volumetric flow rate on the dynamic behavior of pipes conveying air–water two-phase flow. Besides, the normalized volumetric-flow-rate stability envelope for the dynamic system is obtained.

Heavy oil production in deepwater is a major challenge to pipeline technology due to high viscosity and associated high pressure drop. In this chapter, we propose to apply active electrical heating in multilayered composite pipelines for heavy oil production in deepwater. A thermal-hydraulic analysis is carried out to evaluate the pressure drop reduction and power input requirement. We concluded by comparative numerical studies that the heated sandwich pipeline provides a significant pressure drop reduction and thus a boost of mass flow rate of the oil production for a given available pressure drop between the wellhead and the separator.

Buckle propagation of local collapse appearing in the damaged pipes is one of the failure modes that are of particular interest for deepwater application. The local collapse can propagate along the pipeline for long distances in both directions when the external pressure magnitude is up to the propagation pressure. In this chapter, the buckle propagation pressure of sandwich pipes (SP) with different material properties and geometric characteristics is investigated by numerical simulation using Python programming language based on general finite element code. The results of the pressure history data obtained are verified by comparing those published previously. The effect of material properties, geometric characteristics, and adhesion conditions on the propagation pressure are analyzed.

In this chapter, improved lumped parameter models are applied for transient thermal analysis of multilayered composite pipeline with active heating, which is essential for flow assurance design and operating strategies of deepwater subsea pipelines. Improved lumped models for transient heat conduction in multilayered composite pipelines are based on two-points Hermite approximations for integrals. The transient energy equation for the bulk temperature of the produced fluid is transformed into a set of ordinary differential equations in time by using a finite difference method. The coupled system of ordinary differential equations for average temperatures in the solids and bulk temperature of the fluid at each longitudinal discretization point along the pipeline is solved by using an ODE solver. With the proposed method, we analyzed the transient heat transfer in stainless steel–polypropylene–stainless steel sandwich pipes (SP) with active electrical heating. Convergence behaviors of the average temperature of each layer and the bulk temperature of the produced fluid calculated by using the improved lumped models (H0,0∕H1,1 and H0,0∕H1,1 approximations) against the number of grid points along the pipelines were presented. Case studies were performed to investigate the effect of the linear rate of power input and the average velocity on the bulk temperature distribution of the produced fluid.

Sandwich pipes (SP) can be an effective solution for the ultra-deepwater submarine pipeline, combining high structural resistance with thermal insulation capability. Besides polymer, steel fiber reinforced concrete (SFRC) can be another choice for the annular material, based on the characteristics of high fracture toughness and good adhesion with metal. The purpose of this chapter is to investigate numerically the ultimate strength of SP filled with SFRC under external pressure and longitudinal bending. The mechanical behavior of SFRC is simulated using a Concrete Damaged Plasticity (CDP) model whose parameters are estimated by uniaxial tension, compression, and four-point bending tests. The applicability of the parameters obtained is verified by simulating the compression and four-point bending tests, where the results show good correlation between measured and predicted numerical values. Pressure–curvature ultimate strength for SP with perfect adhesion and no adhesion interface condition is obtained. Besides, a parametric study is performed to investigate the effect of the thickness of each layer on the pressure–curvature collapse envelope of SP.

Fundamentals of thermal analysis of pipelines are presented in this chapter. Formulations for heat conduction in single-layer and multilayer pipelines are presented. The steady-state distribution of the temperature of produced fluid along the pipeline is determined analytically.

The electricity demand of offshore oil and gas platforms are traditionally supplied by gas turbines operating with natural gas extracted from the field or fossil fuels emitting CO2 and NOx. Offshore wind power is an interesting alternative to supply such a demand as it can be produced close to the oil and gas field and providing clean and renewable electricity. The objective of this research is to investigate, as a preliminary approach, the techno-economic viability of supplying electricity demand of an oil and gas field by a floating offshore wind farm. An oil and gas field locates in the southeast of the State of Rio de Janeiro, Brazil, with a distance of about 130 km from the shoreline, is selected as a case study. The wind resource at the local is obtained using in-situ measured data. Four wind turbines are studied and compared through their capacity factor and energy production. Afterward, four wind farms composing of the selected turbines are proposed based on the available wind energy and the field demand. The cost of energy produced by the wind farm is calculated, and the results are compared to the conventional method of the electricity supply.

Sandwich pipes (SPs) composed of two concentrically steel tubes with a strain hardening cementitious composite (SHCC) filling core is a new concept designed for oil and gas transportation in deep waters. In this concept, the SHCC core is the most critical component that should withstand the combined loading of high hydrostatic pressure and bending moment. This paper proposes a particular concrete damage plasticity (CDP) model for the SHCC core based both on experimental data and on the continuum damage mechanics theory. The basic fundamentals of the CDP model can be divided into three major issues, namely, damage evolution, yield criterion, and plastic flow rule. For the damage evolution, two models of damage variables, under tension and compression, respectively, were built based on uniaxial experimental data available and the fracture energy theory. For the yield criterion, the parameters for the Lubliner model were fitted according to available experimental data from uniaxial and biaxial compressive tests. For the plastic flow rule, the dilation angle was deduced from the results of triaxial compressive tests combined with the Drucker-Prager type plastic flow rule. Finally, four-point bending tests were carried out on SHCC specimens and collapse tests were conducted on SP models to allow a correlation study between experimental data and results obtained from numerical simulations incorporating the proposed CDP model. The correlation between numerical and experimental results showed good agreement, demonstrating that the proposed CDP model can accurately reproduce the mechanical behavior and damage distribution experienced by an SHCC material.

The increasing of deepwater oil field developments brings a growing need for thermal management to prevent hydrate and wax formations in the subsea production system, due to the low environment temperature and long-distance transportation. Pipeline insulation coating is a typical strategy for thermal management. In a subsea production system, pressure, temperature, flowrate, and length of each flowline vary, leading to different thermal performances of the transported fluid. Therefore, the insulation coating should be carefully designed from the overall perspective to minimize the total material volume, thus reducing the cost. In this paper, an optimization model for the insulation material volume of a rigid subsea flowline system is proposed. Then, the best insulation thickness of each subsea flowline can be determined under given flow parameters and temperature requirements. The factor that defines the temperature drop from the riser base to the top termination is introduced and analyzed. There is a proper temperature drop factor associated with the insulation material volume for subsea flowlines, as well as a proper insulation capacity for the risers. This optimization model can define the subsea system insulation and provide reliable results for cost estimation.