bluuebunny/crossref_metadata_2025_split huggingface dataset:
SS: Subsea Well Intervention: Development of a Deepwater Subsea Well Intervention Package Control System
Authors: Nellessen Peter 
Published: July 2010

Abstract
The paper describes the ongoing work, overall approach and process used to develop a deepwater subsea well intervention control system using structured risk and reliability principles and hardware based upon remotely operated vehicle (ROV) control technology. It discusses the selection of IEC61508 and IEC61511 as the governing standards for development of the controls architecture and certification of this deepwater well control system. It also presents the challenges that have to be addressed when using ROV hardware for well control and describes the methods implemented to overcome system deficiencies. The methods used are currently being vigorously applied throughout the control system's development stage to insure the entire control system and not just its components, will be highly reliable, manufactured, tested and certified in accordance with the principles of IEC60508/61511 to a Safety Integrity Level of 2 (SIL 2).

Introduction
ROV system elements include mechanical, electronic, electrical and hydraulic components. These components have continually matured and improved in operations over more than 30 years. Today ROVs perform subsea tasks which were previously completed by surface operations from a support vessel. ROVs have now been imbedded with, and integrated into, many subsea installations because they have shown to be valuable and reliable tools. However reliable we all may perceive ROVs to be, component and assembly reliability, based on operational use and factory testing, has largely not been fully demonstrated or documented. One reason for the lack of usable reliability data has been due to the ROV operators who generally have not provided the necessary information to the ROV industry. Even if data was available, many ROV components have evolved over the years so operational history is not long enough to predict component life for many components used in those systems.
Material Innovation for Ultra-Deepwater Performance of Long Term Mooring Cables.
Authors: Fletcher Sara Louise , Calverley Stephen , Cawthorne Stephen , Mohanraj Jagan , Verwaayen Johannes 
Published: July 2010

Abstract
Traditional materials abound in station keeping equipment and materials handling in the offshore oil & gas sector; High grade steels being widely utilised throughout all applications, including mooring systems; Synthetic fibres becoming more familiar for tethering and deployment applications. However, true innovation achieving technological step change is rare, driven by an awareness of inherent risk if there is movement away from traditional solutions.
Mooring cables solutions have gradually evolved over the last 30 years, optimising performance characteristics such as weight, strength, elasticity, fatigue performance, to suit the demands of floating production facilities which are being utilised in ever deeper locations & more extreme environments. The conventional materials of steel wire ropes and synthetic fibre have been developed within their property range to match the current requirements but limitations are being reached:Strength to weight ratio of steel moorings is becoming prohibitive in ultra deep locations;Elongation of polyester tethers becomes excessive in ultra deep locations;Creep in HMPE tethers can be an issue in long life systems;High load cases require large diameter products which create complex and high risk installation requirements;Synthetic fibres are sensitive to mechanical damage.
This paper outlines the developments in mooring cable technology since its inception and reviews two key development programmes:
The first is development methodology of a new metallurgical chemistry that achieves the highest strength to weight ratio steel mooring cables. This collaborative project between Corus and Bridon resulted in an UHCSi-Cr grade final hot dip galvanised wire utilized in a spiral strand with 25% weight saving over historical performance.
The second being the step change innovation in materials and material processing developed by Bridon that introduces a synthetic wire product which can be directly substituted into a wire rope construction. This offers a solution for reliable, predictable deepwater permanent moorings with the light weight and elasticity of synthetic fibre tethers, but of robust constructional characteristics and reliable mechanical terminations of traditional steel wire rope solutions. The research, development and test programme will be presented with relevant performance properties for a mooring solution.
Failure Mechanisms of 8630M/625 Subsea Dissimilar Joints and Testing to Assess Performance
Authors: Bahrami Amir , Gittos Mike , Pisarski Henryk , Woollin Paul 
Published: July 2010

1. Abstract
Fusion welded buttered connections are an integral part of subsea oil and gas production systems and typically comprise a nickel alloy buttering weld deposit on an alloy steel forged hub, tee or elbow, which is postweld heat treated, and a nickel alloy closure weld, which is between the buttering and a pipeline steel (hence the term ‘dissimilar joint’). In service, piping systems are protected by cathodic protection (CP). The CP provides a potential source of hydrogen which can be absorbed by the steel and, in the presence of sufficient amount of stress, can result in failure at the interface between the buttering deposit and the forging. In order to avoid future failures, it is important that the fracture mechanisms are understood and that there is a means of establishing fitness-for-service. The present paper describes the zones sensitive to hydrogen embrittlement (HE) in the buttering layer's partially mixed zone (PMZ) and summarises results of fracture mechanics tests carried out to assess HE of these interfaces, in seawater under seabed conditions. The paper further highlights the remaining issues that need to be addressed to ensure safe operation of these components.

2. Introduction
Subsea buttered connections are subject to CP, primarily using sacrificial aluminium anodes, which give an applied potential of approximately -1100mVSCE., which may result in HE, if the necessary conditions are met. The HE resistance of subsea buttered interfaces depends on three primary factors: material combination, buttering welding procedure and postweld heat treatment (PWHT) [1]. Each of these influences the microstructure and chemistry across the interface and unless specifically selected for resistance to HE, the joint is susceptible to failure. Whilst the vast majority of subsea joints have given successful service, a small number has failed. These failures have mainly involved installed components which have not been in service[2].
FDPSOs: The New Reality, and a Game-Changing Approach to Field Development and Early Production Systems
Authors: Harris W.D. , Howard Harry J. , Hampshire Kenneth Christopher , Moore Jeffrey Allen , Bayne Kenneth J. , Pepin-LeHalleur Jean 
Published: July 2010

Abstract
The Azurite field development, installed in the Republic of Congo in 2009, employed the industry's first Floating, Drilling, Production, Storage and Offloading (FDPSO) vessel to develop the field. While the FDPSO concept has been a subject of interest within the industry for some time, the Azurite project team took the FDPSO from concept to reality.
The concept has tremendous potential as a " game changer?? for field developments, whether it is employed to unlock the value of marginal fields in deepwater - even in a low oil price environment - or as an early production system. Because the concept employs a drilling rig onboard the vessel, traditional challenges regarding deepwater drilling rig day rates and availability are eliminated.
This paper summarizes development of the Azurite field as a way of providing context for evolution of the FDPSO concept. This paper also highlights other application for FDPSOs, and discusses some of the key variables that determine the suitability of the FDPSO concept for use in field developments.

Introduction
History was made in August 2009 when the Azurite field began producing offshore Republic of Congo [1]. Azurite employed the industry's first Floating, Drilling, Production, Storage and Offloading (FDPSO) vessel to develop the field. While the FDPSO concept has been a subject of interest within the industry for some time, The Azurite team made the FDPSO concept a reality. It is a robust concept that has potential for much broader application, as the number of large discoveries in deepwater shrink and the industry seeks new ways to monetize stranded pockets of oil and gas.
This paper will reflect on the project technical and economic drivers that led the Azurite project team to select the FDPSO concept. This paper will also discuss other applications for the FDPSO, and identify key variables that determine suitability of the FDPSO concept for use in field developments.

Azurite: Inspiration for the Concept

Discovery and Appraisal
The Azurite Marine Field lies within the Mer Profonde Sud (MPS) block offshore Republic of Congo, just north across the border from Cabinda Block 14. Water depths across MPS range from 1100 - 2000 meters.
Azurite field was discovered in January 2005 with the Azurite Marine-1 (AZRM-1) well. The field was subsequently appraised in late 2005 and early 2006 with the drilling of AZRM-2 and AZRM-3 wells. Each of the latter two wells was sidetracked (ST). AZRM-2ST was also cored and tested. Aquifer support was found to be essentially non-existent along the producing trend, necessitating the requirement for water injection to support reservoir pressure.

Field Size Description
The AZRM-2 and AZRM-3 wells were ST to appraise the four fault blocks of the field as shown in Figure 1 below.
Subsea Hardware Installation from a FDPSO
Authors: Stensgaard Thomas , White Charles , Schiffer Kevin 
Published: July 2010

Abstract
Subsea installation campaigns in support of deepwater field developments are expensive and require specialized vessels to carry-out the work scope. The traditional method entails deploying a costly subsea construction vessel, complete with remote operated vehicle (ROV) capabilities, survey and heave-compensating cranes. However, with a Floating, Drilling, Production, Storage and Offloading (FDPSO) postioned directly over the drill center, a new alternative to the traditional subsea installation campaign came into view. This paper presents the unique challenges related to subsea hardware installation from an FDPSO, and the methods developed to overcome those challenges.

Introduction
The Floating, Drilling, Production, Storage and Offloading (FDPSO) concept requires that it is located over the wells for direct access, and so the ability to perform subsea construction and intervention activities directly from the host becomes a real possibility. The FDPSO provides a large stable platform from which these activities can be accomplished, but it has limited access and maneuverability, and so these challenges must be addressed.
These challenges were met and overcome in the pioneering Azurite field development in Mer Profonde Sud (MPS) block offshore Republic of Congo. The FDPSO was fitted with a working class remote operated vehicle (ROV) spread, along with a 100 tonne heave-compensating crane mounted to the deck. The 100 tonne crane was sized to install hardware as heavy as subsea trees.
Some of the equipment deployed from the Azurite FDPSO included: subsea trees, flexible well jumpers, steel tube flying leads and electrical flying leads.
OTEC Power Efficiency Challenges
Authors: Hurtt James , Pellen Alain , Nagurny Nicholas John 
Published: July 2010

Abstract
The maximum possible Carnot thermal efficiency of an Ocean Thermal Energy Conversion (OTEC) power system is about 7% as it exploits the water temperature gradient between the surface and the deep ocean, which is only slightly over 20 degree C in tropical waters. The overall efficiency of a multi-megawatt-sized OTEC electrical power plant, all inclusive from seawater to net electric power, is typically around 2%. Only about half of the water temperature gradient can be directly harnessed across the power cycle, as the rest is needed for heat transfer and mass flow to maintain economical heat exchanger and seawater pump sizing. About a third of the gross power generated is consumed pumping seawater, powering auxiliary systems, and in power transmission losses. This paper reviews efficiency as it relates to the OTEC power cycle. OTEC has enormous potential as a source of clean, renewable, and base-load electricity for many nations, territories and states near tropical waters. As OTEC technology matures, large floating OTEC plants are expected to produce energy carriers or synthetic fuels that can be shipped to energy consumers. This paper will provide a current review of the various components used by one OTEC power cycle, their respective efficiencies and their contribution to the overall OTEC power plant economics. A thorough understanding of the efficiency losses, power burden, and potential areas for optimization is critical for OTEC to become an economically viable resource. This paper provides recommendations for the design of the OTEC plant main components and gives guidelines to optimize efficiency such that high quality power can be sold to the utility at competitive rates. Finally, the results of a parametric study of OTEC size in terms of Megawatts produced shows the efficiency gains that can be achieved with large scale OTEC power generation plants.

I. Introduction
Global energy demand is increasing rapidly. Growing populations and higher standards of living worldwide are pushing the limits of existing energy resources. At the same time hydrocarbon reserves are becoming harder to find. There is growing global concern for energy security and environmental sustainability. Global development and commercialization of renewable technologies is required before existing resources become scarce. For instance: wind energy has been used through the centuries but was surpassed during the Industrial Revolution by coal and oil. However, over the past decade, wind power has seen exponential growth as an energy resource (2009 US DOE). Solar and wind energy have the economic advantage of free " fuel?? but come with the intermittent and variable nature of that " fuel?? source. Ocean thermal energy enjoys the benefit of the large thermal storage of ocean waters and can therefore provide a base-load source of electricity to coastal areas in tropical waters and energy carriers to energy consumers.
Figure 1 is a map showing the vast worldwide OTEC resource.
SS: Metocean: Comprehensive Hindcast of Hurricane Ike (2008) in the Gulf of Mexico
Authors: Cardone Vincent J. , Cox Andrew T. 
Published: July 2010

ABSTRACT
The immense impact of Hurricane Ike (2008) on Gulf of Mexico (GOM) offshore infrastructure and production is unexpected for a Saffir-Simpson Scale (SSS) Category 2 hurricane. This paper describes a comprehensive hindcast of the surface wind and sea state fields generated by Ike that shows that the extreme ocean response is mainly caused by a marked expansion of the wind circulation after the eye of the storm crossed the western tip of Cuba, leading to storm with a large radius of maximum wind speed and a shelf-like radial wind speed profile. The modeling of these attributes required the description of the radial pressure distribution in the boundary layer in terms of a double exponential analytical formulation. The fitting of that functional form utilized all conventional meteorological data, high-temporal density flight level measurements made by reconnaissance aircraft and remotely sensed satellite meteorological data within an analyst-assisted workstation that allows the fitting of either the classical single exponential form or, if appropriate, the more complex form. The surface wind field is specified by solutions of a newly recalibrated primitive equation mesoscale boundary layer model augmented by available kinematic analyses of the inner-core wind structure derived directly from measured wind data. The wave response is hindcast by a proven third generation (3-G) spectral wave model adapted to GOM at high resolution that includes shallow water effects and incorporates a saturation surface wind drag formulation consistent with recent hurricane inner core measurements of same. The hindcast and available measurements support that Ike generated peak significant wave heights of about 45 feet (~14 m) in the north central GOM. The hindcast is compared to public-domain wave measurements currently available and good skill is evident. In the near term these results aid post-mortem engineering studies conducted to ascertain causes and modes of failure of damaged platforms and other infrastructure and to assess the suitability of related designs. Of longer term significance, the hindcast methodology applied to Ike has been used to incorporate the impact of lower ranked SSS hurricanes and of all hurricanes that exhibit the non-classical radial pressure and wind structure on the specification of extreme metocean criteria derived either by the direct historical or deductive approaches.
Parque das Conchas (BC-10) - An Ultra-Deepwater Heavy Oil Development Offshore Brazil
Authors: Stingl Kent H. , Paardekam Albert H.M. 
Published: July 2010

Abstract
Parque das Conchas is an ultra-deepwater heavy oil development located in the northern Campos basin offshore Brazil. The project is a joint venture between Shell, Petrobras, and ONGC. The first phase of the project is the development of 3 independent subsea fields tied back to the centrally located turret moored floating, production, storage and offloading (FPSO) host facility entitled the FPSO Espirito Santo. The phase 1 Abalone, Ostra, and Argonauta B west fields are small to medium in size, with low-pressured reservoirs, and range in oil gravities from 17O to 42O API. A fourth 16O API gravity heavy oil field requiring water flood, Argonauta O north, will be tied back as part of phase 2 and is planned to be ready for production in 2013. The phase 1 subsea infrastructure consists of 10 producing wells and 1 gas injection well connected via 140 kilometers of pipelines and flowlines ranging in size from 6?? to 12??, 15 flowline sleds, 2 production manifolds, 2 artificial lift manifolds housing a total of 6 vertical subsea separation caissons with 1500 hp ESP's, 25 jumpers, all of which are serviced by 30 kilometers of high voltage multi-circuit electro/hydraulic umbilicals and 20 kilometers of static electro-hydraulic umbilicals. The FPSO Espirito Santo is a converted 1975 VLCC moored in 1,780 meters of water and equipped to process 100,000 bopd, 50 MMscfpd, with 1.4 million barrels of oil storage capacity. The Parque das Conchas development is the result of a 9-year effort to understand the complex geology, identify sufficient reserves to support a development, identify an economic development concept, and to design, mature and apply the significant new technologies required to safely execute the project during an extremely volatile market period. This paper provides an overview of the development and execution of the project, highlights new technologies that have been developed and implemented and introduces the key challenges, achievements, and learning's in various parts of the project and the tight integration between all disciplines required to successfully deliver the Parque das Conchas project. Additional details can be found in the dedicated support papers have been generated and listed in the Reference section of this paper.

History
The Parque das Conchas development grew out of a substantial exploration and appraisal program commencing in 2000 in which 13 wells were drilled and 6 discoveries were made. The Declaration of Commerciality was signed with the ANP (the Brazilian National Petroleum Agency) in December 2005 and the project was sanctioned in November 2006. The four main reservoirs; Ostra, Abalone, Argonauta B west, and Argonauta O north were named after aquatic shellfish indigenous to the area. Together they form " Parque das Conchas?? or " Shell Park?? in Portuguese. This is the first project taken by Shell from exploration discovery to production. First oil from Phase 1 was achieved on the 12th of July 2009, just 9 years after discovery.
Measurements of the Capillary Pressure-Saturation Relationship of Methane Hydrate Bearing Sediments
Authors: Ghezzehei Teamrat Afewerki , Kneafsey Timothy J. 
Published: July 2010

Abstract
Methane hydrate present in permafrost and sub oceanic sediments has been identified as a potentially large energy source. Producing natural gas from hydrate results in the hydrate dissociating into gas and water, which then become distributed in the pore space according to gravitational, viscous, and capillary forces.
Capillary pressure is a function of the medium (wettability, geometry) and the saturations of all phases (e.g. gas, hydrate, water) in the pore space. The presence of hydrate alters the geometry of the pore space, changing the capillary pressure-saturation relationship from the hydrate-free condition. Understanding the capillary pressure-saturation relationship of hydrate-bearing media is important for modeling the flow of gas and water through that medium, and predicting natural gas production from hydrate-bearing reservoirs. We have developed a method for measuring the capillary pressure-saturation relationship in methane hydrate-bearing sand, and our measurements and modeling aid in understanding the behavior of the gas and water in hydrate-bearing sediment. Our experiments involve hydrate formation in unsaturated sand, saturating the sample, followed by step-wise drainage from full water saturation to residual water saturation while measuring the pressure difference between the water and gas phases. During drainage, a number of intermediate static equilibrium conditions were established during which flow was discontinued. The static equilibrium observations provide water saturation vs. capillary pressure relations. For selected samples, drainage was followed by step-wise imbibition to full saturation.

Introduction
Natural gas hydrates are solid compounds in which a network of water molecules form clathrate structures around small gas molecules such as methane, ethane, and carbon dioxide. These compounds generally form and are stable at elevated pressures and low temperatures where water and the hydrate-forming compounds are available in sufficient quantities. Natural gas-hydrate-bearing deposits in sub oceanic sediments and permafrost regions are estimated to hold an enormous quantity of hydrocarbons, with the primary constituent being methane. Estimates of the volume of hydrocarbons contained in gas hydrates span a large range (from 1 to 5 × 1015 m3 (Milkov, 2004) to 1.2 × 1017 m3 at standard temperature and pressure (Klauda and Sandler, 2005)), and dozens of natural deposits have been encountered. It may be possible to develop some of these deposits to produce natural gas, providing a potential energy resource given that a sufficient amount of hydrate is present, permeability is adequate, the deposit is confined, and needed infrastructure is located nearby.