bluuebunny/crossref_metadata_2025 huggingface dataset:
Molecular Gas Dominated 50 kpc Ram Pressure Stripped Tail of the Coma Galaxy D100*
Authors: Jáchym Pavel , Sun Ming , Kenney Jeffrey D. P. , Cortese Luca , Combes Françoise , Yagi Masafumi , Yoshida Michitoshi , Palouš Jan , Roediger Elke
Published: April 2017

We have discovered large amounts of molecular gas, as traced by CO emission, in the ram pressure stripped gas tail of the Coma cluster galaxy D100 (GMP 2910), out to large distances of about 50 kpc. D100 has a 60 kpc long, strikingly narrow tail, which is bright in X-rays and Hα. Our observations with the IRAM 30 m telescope reveal in total

H2 (assuming the standard CO-to-H2 conversion) in several regions along the tail, thus indicating that molecular gas may dominate its mass. Along the tail, we measure a smooth gradient in the radial velocity of the CO emission that is offset to lower values from the more diffuse Hα gas velocities. Such a dynamic separation of phases may be due to their differential acceleration by ram pressure. D100 is likely being stripped at a high orbital velocity

km s−1 by (nearly) peak ram pressure. Combined effects of intra-cluster medium (ICM) viscosity and magnetic fields may be important for the evolution of the stripped interstellar matter. We propose that D100 has reached a continuous mode of stripping of dense gas remaining in its nuclear region. D100 is the second known case of an abundant molecular stripped gas tail, suggesting that conditions in the ICM at the centers of galaxy clusters may be favorable for molecularization. From comparison with other galaxies, we find that there is a good correlation between the CO flux and the Hα surface brightness in ram pressure stripped gas tails, over ∼2 dex.
Stratégies de publication des dépenses environnementales dans un cadre réglementaire
Authors: Depoers Florence , Jérôme Tiphaine
Published: April 2017

Les dépenses environnementales (DE) d’une société constituent un outil d’évaluation et de suivi de sa performance environnementale. Le potentiel informatif de cet indicateur n’a pas échappé au législateur qui oblige les sociétés cotées à publier leurs DE. Notre recherche mobilise le courant de la légitimité pour identifier et expliquer les stratégies de réponse à cet item sur un échantillon de sociétés cotées françaises. Une analyse de contenu permet d’identifier trois stratégies : la non-réponse, la réponse de façade et la réponse substantielle. Les tests montrent plusieurs facteurs explicatifs associés à ces stratégies : la critique environnementale, l’actionnariat ISR et la sensibilité du secteur d’activité. Notre recherche contribue aux débats académiques et réglementaires sur la normalisation de l’information environnementale en révélant et expliquant les comportements des acteurs face à la loi.
Repenser les liens entre Bruxelles et son port : un enjeu d’aménagement pour la zone du Canal
Authors: Mazy Kristel
Published: April 2017

Le projet urbain, par la démarche souple et transversale qu’il produit, est emblématique des concepts urbanistiques contemporains. Cette approche peut-elle opérer une reconnexion entre villes, ports et fleuves ? A contrario, pourrait-elle renforcer la déconnexion en cours, dans un contexte où les logiques de marché sont plus favorables aux sphères d’économie résidentielle qu’aux sphères productives ? Cette question se pose particulièrement à Bruxelles, dans la zone du Canal, intersection d’enjeux majeurs : densification urbaine dans un contexte de croissance démographique, redéploiement du fret fluvial comme alternative durable au réseau routier et amélioration de la gestion de l’eau. L’objectif de cet article est de cerner l’évolution de la relation ville-port par les interactions entre les projets des différents acteurs concernés. À travers une approche spatio-temporelle, les résultats montrent que via leurs matérialisations, les projets participent à reproduire les coupures fonctionnalistes de l’ère industrielle, causées par l’environnement économique dans lequel ils s’inscrivent. Par contre, à travers leur processus, de nouveaux cadres de dialogue ville-port apparaissent. Ces constats fondent quelques pistes pour une reconnexion de la ville et de son port.
De relatie tussen Brussel en de haven herzien: een uitdaging in de inrichting van de Kanaalzone
Authors: Mazy Kristel
Published: April 2017

Wat het stadsproject zo kenmerkend maakt voor de moderne stedenbouwkundige concepten, is de soepele, transversale aanpak. Kan zo'n aanpak een herkoppeling van steden, havens en rivieren teweegbrengen? Of zal die de huidige ontkoppeling net versterken in een context waar de marktlogica gunstiger is voor de wooneconomie dan voor de productieve economie? Deze vraag is vooral prangend in de Brusselse Kanaalzone, op de kruising van grote uitdagingen: stedelijke verdichting in een context van bevolkingsgroei, herontwikkeling van het riviertransport als duurzaam alternatief voor het wegtransport en verbetering van het waterbeheer. Dit artikel zal meer inzicht geven in de evolutie van de relatie stad-haven door de interacties tussen de projecten van de verschillende betrokken actoren. Op basis van een ruimtelijke en temporele benadering tonen de resultaten aan dat de projecten, door hun concrete invulling, bijdragen tot het overnemen van de functionalistische breuklijnen uit het industriële tijdperk, die teweeggebracht werden door het heersende economische klimaat. Uit het projectproces ontstaan echter nieuwe kaders voor dialoog tussen stad en haven. Die vaststellingen vormen de basis voor enkele denkpistes met het oog op de herkoppeling stad-haven.
The Determinant of the Employment-Social Protection Relation in Turkey
Authors: Günaydın Davuthan
Published: April 2017

Social protection can be recognized as one of the most significant social achievements of the last century. In this study one of the most important issues of labour market in Turkey - employment-social protection relationship - will be evaluated. It can hardly be argued that Turkey has a comprehensive social protection system. An important part of people who are at the age of working are not covered by the social security system with reasons such as: low labour force participation rate, prevalence of informal employment, child labour, high share of employment in the agricultural sector, the weakness of the social security system and problems of labour market regulation. This situation increases the need of social protection systems. On the other hand, weakness in coordination between the institutions those operate in the field of social assistance and lack of appropriate criteria in determining the real people in need cause inefficient and inadequate supplying of services and inefficiency in using sources.
How Does IT Capability Impact Organizational Agility in the Supply Chain Context?
Authors: Bi Rui , Davison Robert M. , Kam Booi H. , Smyrnios Kosmas X.
Published: April 2017

Organizational agility is regarded as a strategic capability, helping firms to compete, survive, and succeed in fast changing environments. Companies with greater IT investments are expected to be more agile. However, the issue of whether IT is an enabler or impeder of agility still remains unresolved. Drawing upon resource-based view theory, the authors test a theoretical model that integrates IT capability, supply chain capability and organizational agility. The authors propose that IT capability enables the development of a higher level of supply chain capability which is embedded within inter-firm processes and in turn enhances agility. Structural equation modeling is employed to test their theoretical conceptualization of 310 Australian fast-growth small-to-medium enterprises across different industrial sectors. The results show that IT capability does contribute to firm agility through enhancing inter-firm supply chain processes. This research highlights the role of IT-enabled intermediated processes and the ways in which IT is used by firms to enhance core business processes.
Applying the User Experience Study of a Virtual Multi-Cultural Community in a Service Re-Design
Authors: Blažič Borka Jerman , Jerman-Blažič Andrej , Arh Tanja
Published: April 2017

The aim of the research work presented in this paper is to explore a virtual-user community's influence on the design of a new, multimedia-based Internet service. The virtual communities considered here are the researchers and associated administrative staff, who are working on, or managing, collaboration projects or common tasks in distant laboratories all over the world. The paper reflects the attitudes and the cultural background influence on the technology adoption by the studied community. The user experience were analysed and then applied in the re-design of a new service developed within the Virtual Conference Centre Portal (VCCP) – Global Plaza. The studies were carried out with communities coming from three continents: Africa, South America and Europe. The paper gives a brief presentation of the VCCP's service facilities and an analysis of the results of the performed studies.
Proposition and Test of an Integrative Model for Media Use
Authors: Chimenti Paula , Nogueira Roberto , Mazzon Jose Afonso , Rodrigues Marco , Hupsel Luiz Felipe
Published: April 2017

Digital technologies are changing media consumption in many markets. This study offers and tests a model to analyze the factors that influence electronic media usage in an emerging market; Brazil. Through a survey, a sample of 1.000 cases was collected, capturing consumers' perceptions about five media (Broadcast TV, Pay-TV, Internet, Mobile Phones, and Game Consoles). Using SEM, the study found that Attitude is influenced by Image, Entertainment and Content, followed by Communication and Habit. Also, Attitude is a strong predictor of Satisfaction, while Attention is explained by Entertainment and Satisfaction. The model explained 80% of Attitude and 90% of Satisfaction.
Intervention-Less Multi-Zone Stimulation System - A Case Study
Authors: Murdoch Euan , Robertson Bruce , Munro Christopher , Edwards Andrew
Published: April 2017

Driven by ever increasing associated costs, the industry has long sought an enabling technology to expedite hydraulic fracture cycle times in high cost environments such as offshore. Remotely operated completion tools have been proven to provide these efficiencies and can positively influence the viability of these multi-zone stimulation projects.

This paper will focus on the planning and execution of an offshore North Sea lower completion to present a methodology to remotely access and isolate the reservoir during multi-zone stimulation operations. Innovative technologies utilized in this case study are presented which effectively minimize the cycle time of the stimulation process while providing a high level of contingencies to account for a panoply of scenarios which could occur through-out the operation.

There are several techniques and methodologies which have been deployed to efficiently stimulate multi-zone, horizontal wells in offshore locations such as those found in the North Sea; technical papers such as (Langford 2014) discuss these in detail. This paper will describe the successful deployment of a novel lower completion system into a Southern North Sea extended reach well in June 2015 which targeted the a sandstone formation of the Lower Permian (Rotliegend) strata.

The selected remotely operated lower completion system incorporates multiple communication methods on-board to permit remote functioning of flapper isolation valves, to compartmentalize the reservoir internally, and remote operated stimulation sleeves to access the reservoir, which effectively eliminates the need for intervention between treatments, ultimately improving fracture cycle time and reducing risk while providing operators with realistic contingencies in the event of screen-out.
Marine Seismic Acquisition using Autonomous Marine Vehicles Towing 3D Sensor Arrays
Authors: Pai S. , Yandon E. , Moldoveanu N.
Published: April 2017

Marine seismic data is typically acquired by using towed-streamers due to their high efficiency, easy implementation, and narrow-azimuth (NAZ) acquisition geometry. This method usually results in good-quality seismic data for noncomplex geological environments and is a well-established methodology. However, this method is limited in obstructed areas or in areas with very shallow water where streamer vessels cannot be used. We present two field tests of autonomous marine vehicles (AMVs) equipped with 3D seismic sensor arrays to record marine seismic data concurrently with OBC seismic acquisition missions ongoing in the same area.

The field tests evaluated the operational aspects of the AMVs and demonstrated that the vehicles equipped with 3D arrays can be used to acquire seismic data that is usable and comparable with seismic data obtained from the associated ocean-bottom cable (OBC) surveys. The vehicles proved their ability to hold station and record and transmit QC data back to the survey vessel. The ability to use the vehicles to acquire data in areas previously hard to reach opens the door to potentially deploy the vehicles during streamer surveys to acquire data with offset in excess of 20 km. Shots can be recorded by the vehicle placed at predetermined locations to record ultra-long offset data, which can assist in building velocity models with full waveform inversion.

The AMV is capable of carrying out a number of functions over a longer time frame and at lower cost than when using traditional methods. Its ability to maintain position in a holding area or travel to a new location, when needed, through GPS coordinates optimizes seismic surveys without compromising results. As offshore exploration and production move into deeper and more remote areas, the seismic industry can increasingly rely on autonomous vehicles for support.
The Benefits and Limits of FPSO Standardisation
Authors: Wyllie Michael , Newport Andrew , Mastrangelo Carlos
Published: April 2017

There is renewed interest in the oil and gas industry in standardisation as a mechanism for cost reduction, driven by the present low oil price and a search for efficiencies in project execution. However, the implementation of any approach to standardisation requires clarity about the objectives, benefits, and compromises that are required.

This paper reviews the different approaches to standardisation that can be considered for FPSOs, examines historical examples of standardisation, and the degree to which these examples have been successful. In particular, the paper addresses the extent to which design replication is possible, and the impacts of field conditions, regional regulatory framework, and client specifications on standardisation. Based on lessons learnt from the industry, together with in-house experience of FPSO design and operation, the paper will provide guidance on the extent to which standardisation can be achieved, the areas in which it can be applied, and the potential obstacles to its successful implementation.
Selective Perforation and Design of Multi-Pattern Infill Wells in Field Development Planning and Optimization Under Geological Uncertainty
Authors: Bello O. , Awofodu D. D. , Oppelt J. , Ganzer L. , Holzmann J.
Published: April 2017

About 70% of the world's oil and gas fields are brownfields with production history of 25 years or older. These makes additional recovery from brownfields a focus of interest for the industry. A handful of known technologies exists which have been applied to brownfield redevelopments in a timely and efficient manner to maximize oil recovery. In this paper, we present an innovative approach to rejuvenate brownfields which relies on the application of direct search methods to place, design and selectively perforate multi-pattern infill wells in unexploited hydrocarbon regions while considering multiple history-matched models and geological uncertainties.

The field development optimization (FDO) approach requires the definition of design parameters for efficient well placement and selective perforation in untapped sweet spots using I-J-K coordinates. Fluid saturation distribution from a finite difference reservoir simulator at the end of production history is utilized to identify unexploited regions. Sampling techniques are applied to design parameters to screen the solution space for the best candidates that satisfies the FDO problem. Optimization of selected best candidates are performed using the genetic algorithm (GA), level-set optimizer (LSO) and the covariance matrix adaptation evolution strategy (CMA-ES). In addition, we take into consideration the influence of geological uncertainties on multi-pattern well placement and oil recovery maximization. A partially real field model is used to test proposed FDO approach.

Oil recovery maximization and overall optimization time is compared for all three optimization methods evaluated. Using fluid saturation distribution realized after model validation, favourable unexploited regions are identified for multi-pattern well placement by computing and inspecting the product of permeability-by-thickness-by-fluid-saturation per grid block. Optimization algorithms applied to the FDO problem show the tendency for multi-pattern infill wells to seek untapped regions of the reservoir. Furthermore, we parameterize infill well perforations to control the drainage strategy in our test model. Results show that the optimization of perforations delivered better final solutions. Optimization under uncertainty has an effect on the maximization of oil recovery with lesser effect observed on optimum well placement.
Impact of Ultrafiltration on Sulfate Removal Unit Recovery, Availability and Cleaning Frequency
Authors: Alam Zamir , Boczkowski Maciej , Khoo Su Ann , UdhayaRagavan Perumal , Chaudhuri Bhishma
Published: April 2017

In order to demonstrate the impact of ultrafiltration (UF) on the fouling rate and cleaning intervals of nanofiltration (NF) membranes in seawater sulfate removal application, GE conducted a two-year long demonstration in Singapore. GE's ZW700B UF and SWSR NF membranes were used for this study.

The evaluation was conducted in two phases. During Phase 1, pretreated seawater with SDI between 2.5 and 4.5 was used as feed. During Phase 2, water was pre-treated with the ZW700B UF membrane to yield an SDI of less than 2, before being fed to the NF sulfate removal unit.

In Phase 1, the SWSR-440-ft2 NF membrane showed >99.8% sulfate removal. The membrane also showed very good resistance to fouling; validating the low-fouling properties of the SWSR membrane due to its unique three-layer construction and low surface roughness (typically 10 nm or lower). When the feed water SDI increased to 4, the feed pressure and pressure drop increased but the fouling rate remained low. The unit only needed one chemical cleaning after six months of operation. As expected, chemical cleaning at high pH temporarily reduced the sulfate rejection to 99.7%; but sulfate rejection recovered to 99.8% within two weeks of operation. The temporary increase can be explained by opening of the NF membrane pores due to high pH.

In Phase 2, UF pre-treatment reduced the average SDI to 1.7 and the feed particle count by more than 96%. The NF sulfate removal unit operated more than three months without any noticeable fouling; fouling rate remained low even when the recovery was increased to 80%. Sulfate rejection remained at 99.7% to 99.8%. These results confirm that ZW700B UF pretreatment will reduce NF cleaning frequency and increase the life time of NF membranes. Lower cleaning frequency will lead to lower chemical consumption, lower chemical cost and increased system availability. UF pretreatment will also allow for higher NF Flux and recovery which will reduce the footprint and weight of SRU systems.

GE's ZW700B UF system did not show any decrease in membrane permeability during the duration of the pilot. Membranes were cleaned and recovered by conducting regular backwashes as well as two chemically enhanced backwash cycles at different time intervals.
Wellhead Fatigue Monitoring During Subsea Well Plug and Abandonment Activities
Authors: McNeill Scot , Agarwal Puneet , Bhalla Kenneth , Ge Michael , Leonard Jay
Published: April 2017

Wellhead fatigue monitoring was performed during Plug and Abandonment (P&A) activities of a well in the Gulf of Mexico (GOM). Fatigue monitoring was deemed necessary for several reasons: an older vintage of wellhead system with uncertain fatigue life consumption from previous drilling activities, excessive wellhead stick-up, potentially large rig motions from a moored drilling rig for P&A. Fatigue monitoring was performed to ensure the integrity of the wellhead during P&A operations.

The wellhead fatigue monitoring methods previously developed by several of the coauthors was applied in the wave-dominated GOM environment. Motions of the Blow Out Preventer(BOP) stack were measured and combined with a model of the riser/BOP/wellhead/casing system to reconstruct fatigue damage in the wellhead, conductor and surface casing. To measure wellhead motions, Subsea Vibration Data Loggers (SVDLs) were run with the riser and retrieved via Remotely Operated Vehicle (ROV). Fatigue damage reconstruction in the wellhead, conductor and surface casing was performed directly using the measured motion data and an analytical transfer functions obtained from the calibrated Finite Element (FE) model. Results were provided with fast turnaround time to support operations.

Results demonstrated that fatigue damage rates compared well with pre-deployment predictions, though measured fatigue demand was slightly higher. It was also demonstrated that the primary cause of fatigue damage was due to wave activity at the site. Analysis of low frequency response at the riser natural frequencies indicated that the first few riser modes may have been excited by currents. It was also demonstrated that the low frequency response did not contribute significantly to fatigue life.

The wellhead monitoring methods discussed result in rapid turn-around of valuable fatigue life consumption information, enabling informed decisions to be made in challenging conditions. The monitoring instrumentation and fatigue analysis methods increase the safety and efficiency of drilling, workover and P&A activities. In a larger sense, measured data also serves as a benchmark for analytical model calibration activities, reducing the known conservatism in stress and fatigue in future deployments.
Design Verification and Validation Testing of the Stones Jumper Breakaway Joint
Authors: San Pedro Ramón I , Boubenider Rafik , Neelam Mohan K , Walden Nathan L , Epperson David R
Published: April 2017

The design verification analysis and validation testing of an 8 inch jumper and integrated breakaway joint for the Stones subsea development is described. To control the jumper's failure mode in the event of an accidental pipeline displacement, the assembly was designed such that the maximum bending moment occurred at the location of the breakaway joint. The design and analysis investigated a series of U and M shaped jumper configurations and notched failure point geometries to achieve the desired objective.

Linearly-elastic finite element analysis was performed for a series of code check cases to ensure stresses in the jumper and breakaway joint due to normal in-service loads were below allowable values. Nonlinear elastic-plastic finite element analysis was performed to determine the capacity of the jumper and breakaway joint due to pipeline snag loads. The material properties for the nonlinear elastic-plastic analysis were based on tensile tests on specimens taken from prolongations on the actual breakaway joint forgings. The results of the analysis indicate the breakaway joint notch is the weak point in the final jumper configuration, with a moment capacity well below the rated capacity of the manifold connectors. The fatigue analysis concludes the design life of the breakaway joint is greater than that of the jumper assembly welds.

Validation tests were conducted to confirm the design of the jumper and breakaway joint. A pure bending test was performed on the breakaway joint and a full-scale test was performed on a portion of the jumper (quarter jumper). A test fixture for the full size quarter-jumper pull test was modified to ensure enough stroke was available to fail the jumper sample in a single, continuous pull. Strain gauges, a data acquisition system, and video system were used to monitor and record the strains and displacements along the quarter-jumper test sample. Both tests demonstrated excellent agreement (96%) with the predicted analytical results obtained during the jumper assembly design phase.
Introducing Reactive Flex-Joint: 10–15 Times Prolonged Wellhead Life
Authors: Rørgård Ove , Sønåsen Knut Olav , Ellefsen Øystein
Published: April 2017

Awareness of the challenge with lower available Wellhead fatigue life has increased as the Oil and gas industry has gained more knowledge through advanced analysis and tests. Loads on Wellhead are influenced by movements from drilling rig transferred through Marine Riser and BOP. These loads cause cyclical bending moments and Wellhead fatigue degradation. The intention of Reactive Flex-Joint (RFJ) is to lower the fatigue damage by reducing cyclical bending moment, which is a main contributor for Wellhead fatigue.

It's was built a technology demonstrator (scale 1:25) in 2006 and patent of the system was approved. Later a full-scale workshop test model was constructed including a Flex-Joint (FJ) for simulation of environmental conditions. In addition there were preformed thousands of transient dynamic simulations with irregular sea conditions. An independent company duplicated these analyses and all results are verified by 3rd party. The 3rd party company also approved product qualification and use before offshore deployment. An environmental test through a complete drilling campaign of a new well was preformed spring 2016, verified the technology and efficiency covering a wide variety of environmental conditions. The BOP was instrumented to monitor live bending moments and inclination with and without the RFJ. More than 50 subsea tests proved 55 - 65% reduction of cyclical bending moment meaning 10 - 15 times extension of the remaining Wellhead fatigue life. The conclusion is that a modified FJ can reduce dynamic bending moments transferred from Riser to Wellhead during drilling and Work-Over operations. Reduced fatigue exposure gives increased Well access, improved Well Integrity and significant extended Wellhead fatigue life. The reduction of cyclical bending moments on Wellhead give extension of available days for connection, enabling additional Workover and/or side track drilling resulting in Increased Oil Recovery.
Breakthrough Technology Overcomes Long Standing Challenges and Limitations in Cement Integrity Evaluation at Downhole Conditions
Authors: Kamgang Sebastien , Hanif Amer , Das Rajdeep
Published: April 2017

Typical industry standard for evaluation of cement integrity at downhole conditions is through the use of acoustic measurements. These systems generate compressional acoustic waves which travel through wellbore fluid to impact the casing. Attenuation of these waves is used to derive cement compressive strength or acoustic impedance bonded to the casing.

Some of the long lasting fundamental limitations faced by the current technology are: The wellbore must be filled with liquid for the compressional wave to be able to travel to the casing wall. Heavy muds and solids particles in the mud can cause further complications.The in-situ compressive strength may not fully characterize cement mechanical properties.Micro-annulus condition can be difficult to differentiate from poor bond condition without a separate pressure pass.

A new technology, which uses electro-magnetic acoustic transducers (EMAT), has set a new industry standard for cement evaluation. This new sensor technology is incorporated into an established and highly successful sectored pad-type tool design. This tool design provides multiple measurements azimuthally, making fully compensated measurements, allows good tool centralization in high wellbore deviations, and enables evaluation of multiples casing sizes in a single pass.

The primary mechanical forces responsible for the failure of the cement sheath are shear forces differences between the wellbore and surrounding formation. The new technology measures the horizontal shear wave which responds to the cement in-situ shear modulus coupled to the casing.

EMAT technology is wellbore fluid neutral and as such, eliminates the need of filling wellbore with fluid prior to logging. This presents a very important advantage as the cement condition can now be evaluated in downhole conditions similar to conditions when the well is on production. Additionally, fluid-filled micro-annulus can be better recognized without the need to pressurize the casing.

The wider dynamic range of the new measurement also yields a higher resolution evaluation, provides us with the ability to evaluate cement bond in a wide range of heavy cement slurry density down to ultra-light cements and in contaminated cements, as well as other slurries types such as resins.

This paper will discuss theoretical background, numerical modeling and actual recorded data demonstrating the above breakthrough advancements in cement sheath evaluation at in-situ conditions.

While preserving the advantages of current technology, the EMAT measurement now provides operators with much needed flexibility to analyze, with consistent high resolution, cement bond quality over a wide range of slurry densities. Operators are no longer required to isolate existing opened perforations and load wellbores with fluid in preparation for logging, resulting in significant time and cost savings.
Seamlessly Integrated Subsea All-Electric Systems: Laggan-Tormore as a Case Study
Authors: Pimentel Juliano , Mackenzie Rory , Thibaut Edouard , Garnaud Frederic
Published: April 2017

TOTAL is strongly committed to the strategy to have, in the coming years, seamlessly integrated all-electric systems as part of the available technologies for future subsea and deepwater developments. It is part of the company's road map to accomplish flexible and configurable systems to meet the assets requirements in terms of functionality, safety and availability, but also that can reduce CAPEX and OPEX.

This paper will evaluate the impact of technology change from electro-hydraulic to all-electric system in the recently started Laggan-Tormore field in the UK shelf.

It will be shown that by proposing new all-electric technologies, currently or shortly available, it is possible to reach functional specifications and potentially reduce CAPEX and OPEX keeping system overall availability.

All-electric systems were investigated for Laggan-Tormore, an already delivered project, originally with electro-hydraulic technology, in order to evaluate the pros and cons of their implementation in future fields. Currently available all-electric building blocks were considered in the analysis, such as DC/FO distribution system, electric Xmas trees (or those driven by electric actuators) and electric downhole safety valve. Additionally, a future subsea compression expansion in the field was also considered and subsea power equipment maturity was assessed, as well as the interface with LV distribution and control systems.

This paper will present a proposed all-electric architecture to meet the project's functional specifications. This architecture will be assessed in terms of system optimization and facilities CAPEX.

New ways to safely design subsea power and communication will be presented, with the introduction of recently qualified technology. The benefits in terms of functionality, system availability, CAPEX and OPEX will be discussed.
Pragmatic Solution to Continued Failures of Critical Subsea Connector Bolts
Authors: Chaudhury Gautam
Published: April 2017

A pragmatic robust solution has been developed to combat recurring failures of tension loaded bolts used in subsea wellhead connectors. This is a paradigm shift in tension loaded bolt design that will be inherently reliable; "Maximum possible preload to Minimum allowable mean stress".

Failures of safety critical bolts are continuing for more than a decade in spite of replacing over 10,000 bolts and following QC recommendations from industry subject matter experts. The work has demonstrated that existing practice of extremely high preload has compounding adverse effects on integrity of high strength bolts leading to premature failures.

The proposed robust solution employs a fracture mechanics based fit for service design procedure using engineering critical assessment, fatigue life verification, selection of robust material, and attainable manufacture and installation Q/A and Q/C that can withstand minor unintended deviations to strict specifications.
Johan Sverdrup. Creating a Unique Environment for Successful Drilling Operations in an Accelerating Spotlight Project
Authors: Øregaard Jákup , Carlsen Jørn Andre , Rafoss Svein Inge , Tønnessen Tor , Jones Barry , Henriksen Knut , Gloppen Trond
Published: April 2017

Johan Sverdrup is one of the five largest oil fields on the Norwegian Continental Shelf (NCS), and will be one of the most prominent industrial projects in Norway during the next 50 years. The field will come on stream at the end of 2019 and create enormous value. The resource estimate is between 1.9-3.0 billion barrels of oil equivalents. Drilling operations started with predrilling of eight producers in March 2016. Due to challenging market conditions it was recognized early in the project planning phase that a step change in efficiency was needed.

This paper presents the aggressive goals that were set, the overall strategy brought to play to reach the ambitious goals and key new innovative work practices. The Eight Wells Drilling Campaign has been recognized as very successful in all aspects, and was completed eight months ahead of schedule. The paper describes how a trilateral partnership, consisting of the Operator, the Drilling Contractor and the Main Provider of Drilling & Well Services, together reached aggressive targets for tangible efficiency gains.

Important success-factors and new work practices are described, which include key elements such as long-term and comprehensive contracts, integrated operations, integrated services and a new incentive system. Equally important is the development and implementation of a shared vision and shared priorities. Furthermore, the paper describes how demands from a challenging customer were operationalized, and created engagement and motivation across companies. The development of a joint operating model clarified roles, responsibilities, expectations, understandings and ensured that the same message was given to all. An aligned leadership cooperation both offshore and onshore was identified as important. Technically well-equipped operation rooms offshore and onshore allowing real-time collaboration, video-conferencing and real-time sharing of information across geographical and company boundaries were seen as key enablers. Furthermore, important for the radical efficiency improvements was fast and efficient decision processes made possible by the delegation of operational decision making power to a joint operations team lead by the Operating Company.
Extrapolation of Subsurface Current Observations to the Sea Surface: Applicability and Limitations of Basic Algorithms
Authors: Magnell B. A. , Ivanov L. I. , Morrison A. T. , Ramos R. J.
Published: April 2017

Information about near-surface currents provided in near-real-time is required in a variety of applications. However, direct measurements of near-surface currents are scarce. In the Gulf of Mexico, the oil industry has been collecting current profiles from deepwater rigs, platforms, and moorings in accordance with BSEE Notices to Lessees (NTLs) since 2005. On the rigs and some platforms, these profiles are usually collected with long-range ADCPs positioned beneath the rig/platform keel, so the measured current profiles typically extend from 70-80m below the surface to as deep as 1000m. Unfortunately, only a few stations are equipped to provide good-quality near surface current data. This study assesses the validity and limitations of some simplistic current profile extrapolation algorithms, including approximation of the near surface current by "slab" flow and profile extrapolation algorithms derived from the shape of the measured subsurface profile or from a generic current profile shape.

The analysis is based on data collected by a long-term mooring anchored in approximately 1400m of water in the north central Gulf of Mexico (Green Canyon 782, NDBC ID 42369) and on a year-long data set from a mooring deployed in Keathly Canyon in approximately 1900m of water. The available data include periods of Loop Current Eddies (LCEs), weak cold-core eddies, relatively strong flows characterized by a subsurface current intensification, and high-amplitude inertial oscillations.

Velocity profiles were mapped onto fixed depth levels. The subsurface section of the profiles was used to extrapolate mappings from 80-100m to the near-surface. Our analysis shows that, in the winter and in the absence of an LCE, currents in the upper 80m of the water column were quasi-homogeneous. Although current speed near the surface is likely to be higher than current speed at 80m, there is a 90% probability that this difference does not exceed 10cm/s and a slab flow extrapolation is reasonable. When an LCE is present, the accuracy of extrapolation is better if the shape of the near-surface current profile is based on deeper observations. This is also true for the stratified summer water column. The uncertainties of profile extrapolation are quantified for each data set and for each flow regime.
Kinetics of Fluid Phase Behavior Changes: A Critical Uncertainty for Offshore Field Development
Authors: Lavenson David M. , Kelkar Aniruddha V. , Joshi Nikhil , Portman Lance
Published: April 2017

With increasing pressure on project costs, accepting uncertainty is increasingly less viable for offshore field developments. An urgent issue that affects conventional and novel technologies across the production landscape is that of the kinetics of fluid phase behavior changes. Be it pressure boosting using electrical submersible pumps (ESPs) or separation with novel compact separators, the rates of gas dissolution and evolution are a critical uncertainty. PVT laboratories today report fluid properties at equilibrium points, with a prevailing unwritten assumption that the system can achieve the new phase equilibrium either instantaneously or at a time scale that is negligible when compared with production system residence time scales. However, even anecdotally, many in the industry understand this assumption to be optimistic and recognize there is a kinetic process that must occur to achieve the new equilibrium state. Fluid property measurements – kinetics included – are highly valuable to a variety of disciplines: research engineers, process engineers, flow assurance engineers, and more. To effectively apply fluid property measurements to field development activities, each engineer must have a quantitative understanding of the data uncertainties. The kinetics of fluid phase behavior changes are, however, often overlooked; nearly all industrial process simulators apply equilibrium models, regardless of whether the system has achieved the equilibrium state. As the industry drives towards more challenging offshore fields and focuses on simplifying designs, reducing size, and reducing costs, the result is an increasing risk of consequences due to incomplete evolution or dissolution of gas. Engineers currently have no tools available to predict or estimate the rate at which the gas will evolve from or dissolve into solution. This unknown propagates to potential issues in a variety of applications, including design and optimization of artificial lift systems, design and operation of electrical submersible pumps, subsea or topsides pumping, compact separations, and more generally gas-liquid separations. In this paper the authors share insight and information about challenges in design, development, operation and troubleshooting with regards to the uncertainty in the kinetics of fluid phase behavior. Discussion also covers the value in developing an alternative fluid property measurement for quantifying and predicting the rates of gas evolution and dissolution.
Development of Sour Service Corrosion Resistant High Strength Steel Pipe Grades at TMK
Authors: Panda D. , Lolla T. , Mokirala R. , Metelsky D.
Published: April 2017

API Specification 5CT [1] and NACE MR0175 [2] and TM0177 [3] provide guidelines for the use of carbon steels with desired characteristics in oxygen-free environment containing H2S and CO2. TMK IPSCO has developed a range of suitable grades to meet such service requirements; this paper describes in detail the necessary processing tools that have been developed and implemented to achieve the desired pipe properties and consequently ensure their performance in the well.

It is well known that low alloy carbon steels of higher strengths are susceptible to SSC (Sulphide Stress Cracking) in such sour service conditions. As the strength (and hardness) of steel increases, controlling impurities within the steel matrix becomes critical in the development of pipes for such applications. Development of technologies to reduce the inclusion content and ensure "clean" steel for the production of these grades at our steel production facility in Koppel is presented. Additionally, the use of rigorous heat treatment practices aimed at controlling the micro-structure and mechanical properties of the steel, which are achieved by monitoring and controlling critical parameters such as the furnace temperatures, are discussed. To meet the stringent quality requirements for these grades, improve process efficiency and reduce operational error, the use of automatic hardness testing machines have been implemented to batch process the hardness tests on such grades. Furthermore, a novel use of automated microhardness machine to predict the disposition of test samples to failure during SSC testing is presented.

Investigations of steel specimens have shown that application of "clean" steel practices, like the implementation of TruStir® technology has resulted in a marked and consistent enhancement in the cleanliness of such sour service steel grades. Heat treatment studies point to enhancements in hardness control and distribution resulting from heat treatment practices involving double quench and tempering. Such heat treatment routes are believed to result in a better control of prior austenite grain size and prevent formation of localized "hard" spots in the material, which could become sites susceptible to SSC. Recent developments of the control of furnace operating parameters at our Baytown Heat Treating facility and resulting improvements in the performance of our sour service grades are discussed.

Production of these sour service grades require stringent quality checks as mandated by API specification 5CT and ISO specification 15156. Apart from extensive hardness testing, these grades require prolonged corrosion testing. Aside from standardized testing methods for these grade, our internal microhardness testing of these grades have revealed a relation between the frequency of microhardness distribution and the corrosion performance of these grades. Based on these results, a quick methodology of predicting the corrosion performance of a material is being explored.
Nanotechnology-Based Solution for Offshore Zinc Removal Water Treatment Technology
Authors: Ventura Darryl , Murugesan Sankaran , Kuznetsov Oleksandr , Mazyar Oleg , Khabashesku Valery , Darugar Qusai
Published: April 2017

This paper discusses the synthesis of hybrid carbon nanotube (CNT) and carbon nitride (CNx) membranes for applications in flowback water filtration processes. Due to their intriguing properties, these nanocomposites may be a suitable replacement for conventional membranes found in spiral-wound filter cartridges. The membranes presented here offer a dual-filtration mechanism because nano-sized particulates are filtered out by the porous, high-surface area CNT membrane while charged ions are removed via the CNx particles. This membrane has also demonstrated a unique ability to bind to, and subsequently filter out, divalent ions such as zinc—a common component of completion fluid. In addition, the inherent physical properties of CNTs, such nanocomposites, offer enhanced chemical corrosion resistance and anti-fouling properties.
Shallow Gas and Shallow Water Flow Induced by Natural Gas Hydrate Dissociation in Deep Water Sediments
Authors: Gong Zhiwu , Ren Shaoran , Zhang Liang , Cui Guodong , Liu Yanmin , Wang Yanyong
Published: April 2017

A heat transfer model in NGH sediments during drilling fluid deep-circulation and a dynamics model of NGH decomposition, in which the temperature-difference driving process is mainly considered, are established to evaluate NGH dissociation and gas and water production during deep-sediment penetration. A local overpressure generation model from NGH dissociation is constructed to calculate the induced overpressure and shallow gas (SG) and shallow water flow (SWF) formation under various conditions. Investigated are the effects of drilling fluid circulating temperature and NGH saturation on NGH dissociation and overpressure (SG and SWF) formation processes. The results indicate that the heat conduction from circulating drilling mud to NGH formation is so slow that local overpressure will only be developed within about 1.5m around the wellbore for 9 days of drilling fluids deep-circulation under typical operation conditions. For the typical NGH bearing sediment, an overpressure as high as 2.4MPa will be induced within the formation about 1.5m around the wellbore after about 9 days of drilling fluid deep-sediment circulation. This will exert great threat on the safety of cement sheaths and NGH sediment caps. During deep-sediment penetration and drilling mud circulation, the NGH saturation has more significant effects on NGH decomposition and local overpressure development than mud circulating temperature. 100% increase of drilling mud circulating temperature will result in only 10% increment of the local overpressure around the wellbore, while 100% increase of NGH saturation will result in 130% augment of in-situ overpressure.