bluuebunny/crossref_metadata_2025 huggingface dataset:
Long-Term Applications In the New ISO for the Site-Specific Assessment of Mobile Jack-Up Units and the Use of Skirted Spudcans
Authors: Kudsk Gregers , Stadsgaard Henrik
Published: April 2012

The requirements for the use of jack-up units in long term operations have beenincluded in the ISO 19905-1 International Standard for the Site SpecificAssessment of Mobile Jack-Up Units.

The paper will provide an overview of the verification, fatigue evaluation andthe definition of the inspection programs associated with long-term operationsof jack-ups as combined drilling and production units.

The paper will also address the interaction between the various stakeholdersinvolved in defining conditions for acceptance of such operations in additionto the site specific assessment.

Two actual cases will be used to illustrate the level of analysis applied andwhat it took to obtain the necessary approvals. The cases are both pre-date theISO but contain most of the same requirements in their assessment.

The cases will also provide details of the structural modifications and otheroperational requirements including underwater inspections that were deemednecessary to be able to operate the jack-ups for a period exceeding the fiveyear Class inspection requirement.

The paper will further address the use of skirted spudcans on harsh environmentjack-ups to enhance their operational capability and to permit operations withincreased deck loads thereby facilitating the installation of the productionmodules on the jack-up.

The use of jack-ups in combined drilling and production mode is gainingincreased interest in the offshore industry. In particular as they offer costbenefits solutions for development of marginal fields or second phase enhancedrecovery.Agenda• Long-term use of jack-ups: Background and key issuesLong-term operational casesSkirted Spudcans: Justification, design and operational considerations

Long-term use of jack-ups:

Background

The OTC jack-up session 2012 is intended to provide an overview of the aims andresults of the efforts to develop a comprehensive ISO standard for jack-upassessment.

Long before the decision to create an ISO standard the major stakeholders inthe jack-up industry had moved to create a joint industry effort with thepurpose of creating a uniformly accepted basis for jack-up assessment. Theearly phase of the work started in 1989 with a joint industry project thateventually developed into the recommended Practice of Jack-Up Assessment laterto be known as the SNAME 5-5A document.

When it was decided to move into establishing a workgroup on jack-up assessmentunder the ISO TC67/SC7 Committee the group of participants were to a greatextent formed with people from the SNAME 5-5A work group and the starting pointfor the ISO standard was chosen to be with the SNAME 5-5A as the technologicalreference document.
Qualification of Flexible Dynamic Risers for Supercritical CO2
Authors: Rubin Adam , Wang Christian
Published: April 2012

In the oil and gas industry there is a growing demand for riser solutionsdedicated to high partial pressures of CO2. Part of this demand is driven bydeep water high pressure reservoirs with high CO2 content. In addition there isa growing interest in reinjection of CO2. The reinjection can be driven by adesire to reduce CO2 emission as in Carbon Capture and Storage (CCS) projects, but also as a way of Enhanced Oil Recovery (EOR). In all cases it is likelythat CO2 will be present at high pressures and in its supercriticalphase.

NKT Flexibles is about to complete a three-year documentation and qualificationprogram with the aim of qualifying a broad range of flexible pipe solutions foruse with supercritical CO2 (SCCO2). An important part of the program has beenmaterial qualification. For polymeric materials, the main challenge is the highsolubility in some polymers of supercritical CO2. This leads to potential highswelling and a risk of mechanical damage (blistering) in explosivedecompression situations. Furthermore, supercritical CO2 has a strongextraction power which may result in rapid loss of plasticizer in plasticizedpolymers.

The qualification program included a broad variety of tests qualifying againstpotential failure mechanisms. The testing program is executed on polymers incontact with the bore stream. Results show that cross-linked poly-ethylene(XLPE) inner liner has superior resistance to SCCO2 on all tested parameterscompared to other available liner materials.

For steel materials, the main potential risk when exposed to supercritical CO2is corrosion. High CO2 content together with water forms a corrosiveenvironment which could have some impact on the metals used. For flexible pipeapplication, this is primarily relevant for the carcass material and endfitting which is in direct contact with the bore stream. Selection ofappropriate metallic materials will be based on the actual specification of thebore stream.

This paper will present the full scope and results of the qualification workcompleted for qualification of flexible dynamic risers for SCCO2.

Introduction

For the last 35 years, unbonded flexible pipes have been a key component inoffshore oil and gas production. They represent an alternative solution torigid steel pipes where they have the advantages of faster installation timesand better adapting potential for changes in field layout. These advantagesoften make unbonded flexible pipes a more economical solution than rigid steelpipes.
Mooring Lines - Integrity Management
Authors: Ukani Sandip , Maurel Walter , Daran Renaud
Published: April 2012

The Floating Product Systems (FPS) fleet has increased steadily over the last 2decades and is expected to continue to grow with developments in the world'sdeepwater basins. One of the issues with floating installation is that they aremoored to the seabed and therefore subject to the forces exerted during stormyconditions. These exceptional forces can cause deterioration of the mooringlines and in some circumstances result in mooring line breaks. This has obviousimplications for personnel, asset and environmental safety.

Being able to monitor the tension experienced by the mooring lines enables FPSoperational personnel to proactively take the required measures to maintainmooring line integrity. This paper details the design and installation of a newmooring line monitoring system allowing such mooring integrity monitoring on a FloatingProduction Storage Offloading (FPSO) vessel operating offshore Brazil.

Introduction

SBM supplied the FPSO for deployment in Brazilian waters. The vessel is mooredusing 9 mooring lines bundled in 3 sets of 3 lines at 120° from each otheraround the turret chaintable.

A new mooring line monitoring system was specified for this project. Thepurpose of the system was not only to notify the operations team in the eventof a line break but also to record the line tension experienced over time sothe mooring line performance could be evaluated. The project specification also called for thesystem to have the capability to identify progressive degradation such as linecreep and quantify the need for line retensioning.

Technical Challenges

Many of the systems used in the past to monitor anchor leg load have offeredlimited reliability. Load cells need to be mounted in the load path which leadsto difficulties when maintaining them. Shear pins require modifications to thechain which can affect chain integrity. Strain gauges have issues with water leakage. Moreover the cables required to connect these sensors to the data collectionsystem could become trapped and severed during a subsea intervention like riserpull-in.

When developing the system reliability and robustness was foremost in thespecification. Therefore Pulse decided to use inclinometers in the developmentof the system. An inclinometer was attached to the chain hawse of each leg. This meant that the sensor was outside the load path, enabling straightforward maintenance ofthe sensor. Furthermore, each anchor leg chain can be pulled through the chainhawse to re-tension the chain without affecting the operation of theinclinometer.

In order to avoid the problems associated with cables connecting the system, Pulse used acoustic communication to relay the measured data to the controlroom. Figure 1 shows the type of acoustic receiver used.
Ocean Current from 500 to 1000 Meters in the Gulf of Mexico
Authors: Fan Shejun , Harington-Missin Liam , Oey Lie-Yauw , Guan Xiaorui Amy , Eltaher Ayman
Published: April 2012

As part of the Bureau of Ocean Energy Management, Regulation and Enforcement(BOEMRE) sponsored study for ocean current monitoring from 500 - 1,000 metersin the Gulf of Mexico, this paper describes the methodology and results ofassessing the characteristics of the forcing and occurrence of elevated currentevents.

BOEMRE NTL ADCP data, historical mooring current data and three types ofPrinceton Regional Ocean Forecasting System (PROFS) model data were used forthis study. Based on the analysis of current characteristics, ocean currentkinetic energy distribution and observational data availability, fourrepresentative zones are indentified. For each zone, the long term and eventcurrent profile characterizations and subsurface elevated event screening areundertaken, and long- and short-term full water column current profilecharacterizations (representative current profiles and associatedprobabilities) are derived from selected quality controlled NTL ADCP data, historical mooring data and PROFS model data. These current profiles andspecific riser models for each type (Drilling, SCR, TTR, Hybrid Risers, and TLPTendons) are used to assess the VIV damage, which is documented in theaccompanying paper by Ozturk et al. (OTC 23570).

This study will evaluate the significance of ocean currents in water depthsbetween 500 and 1000 meters on riser and mooring systems, as well as toidentify whether any significant events have resulted. The study results willhelp BOEMRE to define whether monitoring below 500 meters is justifiable inregards to fatigue analysis of riser or mooring systems.

1. INTRODUCTION

Safe and efficient exploration and development of deepwater offshore oil andgas fields require the development of a comprehensive knowledge of the localoceanographic current regime. The study of ocean current monitoring from 500 -1,000 meters in the Gulf of Mexico was sponsored by the Bureau of Ocean EnergyManagement, Regulation and Enforcement (BOEMRE) of the U.S. Department of theInterior. The purpose of this study was three-fold:Assess the characteristics of Gulf of Mexico current forcing in the 500 to1,000 meter range and occurrence of elevated events;To evaluate the significance of ocean currents in water depths between 500and 1000 meters on the fatigue and design of risers, moorings and TLPtendons;Based on the findings, to form a recommendation on whether monitoring below500 meters is justifiable in regards to fatigue analysis of riser or mooringsystems.

This paper describes the activities associated with the first purpose of thestudy. The accompanying paper by Ozturk et al. (OTC 23570) addresses theremaining goals.
Dynamic Stresses and Fatigue Evaluation of Wind Turbines
Authors: Jafri Syed M. , Eltaher Ayman , Jukes Paul
Published: April 2012

Wind turbines and renewable energy devices are important components for thefuture of energy sector. This is due to fast depleting sources of oil and gasall around the globe. Offshore wind turbines offer numerous advantages, due totheir remote location from land, thereby reducing noise, higher power output(due to large wind speeds) and utilization of existing offshore platforms fortheir installation and operation.

This paper presents a general analytical solution for calculation of dynamicbending stresses induced in a wind turbine tower as a result of rotatingimbalance in the rotor blades. The formulation is based on elastic beam theory, with inclusion of rotating imbalance forces. The formulation neglects the bladegyroscopic effects and models only the lateral tower vibrations.

The dynamic stresses are highly important for fatigue evaluation of the steelwind turbine towers. The formulation models the linear elastic response of thetower under the effect of rotor imbalance, and proceeds to compute the dynamicbending stresses as a result of lateral vibrations. The model also includes theeffect of linear viscous damping at the rotor-nacelle at the top of tower, andshows the beneficial effect of damping to suppress vibrations and reducebending stresses. The damping may arise from sources such as aerodynamic dragand internal steel structural dissipation. The motivation of this technicalpaper is to provide a simple analytical desktop tool for an engineer toevaluate the dynamic stresses for a given wind turbine size (tower height, diameter, wall thickness, blades and nacelle mass, rotating imbalance androtational speed), for an initial dynamic stress and fatigue screening, beforeproceeding to perform more comprehensive aero-structural finite element modelsof the wind turbines for simulating the dynamics of the wind turbines.
An ROV-Deployed Deepwater Subsea Sampling System
Authors: Kelner Eric
Published: April 2012

The increase in deepwater production in the Gulf of Mexico and other locationsaround the world has brought a corresponding increase in the use of subseamultiphase flow meters. The placement of subsea multiphase flow meters near thewells provide improved reservoir management, well diagnosis, allocation, aswell as oversight for safety. However, to realize their full potential, multiphase flow meters require timely and accurate fluid properties at meterconditions. Subsea architectures with long flow lines and risers have led tothe realization that well tests and topside samples cannot meet the needs ofthis new measurement technology.

A method for ROV-deployed subsea sampling has been developed in conjunctionwith several major operators to provide a means to capture representative fluidsamples at the multiphase meter or other locations, at various times throughoutthe life of the well. The system has been tested in a high-pressure flowlaboratory, as well as in a tank, to simulate ROV deployment in deepwaterconditions. A significant feature of this sampling system is its proposal of astandardized interface. Making such an interface between the sampling systemand the process fluid available to manufacturers will relieve them from thecosts and complications of developing proprietary systems, with varied designsand procedures. Furthermore, users will have more choices of both equipment andROV vendors, since these components should be interchangeable. This paper willpresent an overview of this sampling system development and some of itsperformance characteristics.

Introduction

The increase in deepwater production in the Gulf of Mexico and other locationsaround the world has brought a corresponding increase in the use of subseamultiphase flowmeters. The placement of subsea multiphase flowmeters near thewell provides improved reservoir management, well diagnostics, and allocation. However, multiphase flowmeters require timely, accurate fluid properties, atmeter conditions, to realize their full potential. Subsea architectures withlong flow lines and risers have led to the realization that well tests andtopside samples cannot meet the needs of this new measurement technology.

A method for a remotely operated vehicle (ROV)-operated subsea sampling systemhas been developed to provide a means to capture representative fluid samplesat the multiphase meter and other locations at various times throughout thelife of the well. The system has been tested in a laboratory and a tank tosimulate ROV deployment in subsea conditions.

One attractive feature of the sampling system is the proposed standardizedinterface. A standardized interface between the sampling system and the processfluid will relieve users and manufacturers from the costs and complications ofproprietary systems with varied designs and procedures. The standardizedinterface will be made available to interested parties. This paper presents anoverview of the sampling system development and testing.
The Belly Spar - Design and Verification of an Ultradeepwater Solution
Authors: Loken Rolf , Laukeland Lars , Hannus Henrik
Published: April 2012

The Spar platform has developed into a well functioning solution for Gulf ofMexico environment. Considering use of this solution in the North Atlantic, themetocean conditions differ by long period swell and fatigue induced by normaloperational seas.

In order to meet these challenges, it is desirable to consider a classic Sparthat is more fatigue redundant than a truss, but the swell requires highnatural periods, to avoid parametric heave-pitch resonance.

A new version of the Spar in response to these requirements is the Belly Spar. It can be considered as a classic Spar with a Belly; starting below the wavesurface and extending down to the hard tank depth. A concrete Spar concept withreduced waterline diameter has also been developed by Aker Solutions for arcticapplication. This concept had the dual benefit of increasing the natural periodin heave as well as reducing the ice load from sea ice

The concept has been developed for a field in the Norwegian Sea, in water depthof 1,200m (4,000ft). The hydrodynamic analyses show excellent performance, however contain assumptions on damping. The design has been by model testing ofthe design in wave and current combination representing 10,000yr events, asshown by results and correlations in the paper.

The design opens up new areas for the Spar platform, with good motions that canaccommodate steel catenary and top tensioned risers. As for previous Sparconcepts, the application is in deepwater and ultradeepwater.

Introduction

The use of the Spar structure for oil and gas production was conceived byEdward Horton in the 80ies, ref. 1. As the first project was realized, Aker gotinvolved in the design and delivery, ref. 2. With subsequent projects cameexperiences and new design variants were developed, the truss Spar was the"next generation" and the cell Spar has been another variant.

The use of the Spar has been limited to the Gulf of Mexico (except for one inMalaysia), with certain metocean conditions, mostly mild weather, butoccasionally a loop current or hurricane event. During a hurricane, theplatform is shut down and the personnel are evacuated.

When considering applications in other parts of the world, the local conditionsneeds to be considered, which may yield changes to the design. Previousevaluations in use in regions with swell have observed challenges with motionresponse. The option for reducing the water plane area by a reduced topdiameter was implemented already in 1976 for the Brent Spar loading buoy andthe influence on the motions thoroughly documented by Haslum, ref. 3.

The truss of a truss spar has been seen as a means of reducing the weight ofthe midsection, between the hardtank and the ballast. However, the trussconcentrates the load path into critical components without redundancy that puthigh requirements on the fatigue design. An alternative means for reducing theweight is to reduce the diameter, relative to the hard tank.
Robotic MFL Sensor and Vibration based Deepwater Riser Monitoring System
Authors: Huang C , Nagarajaiah Satish
Published: April 2012

The safety of deepwater risers is essential for successful operation ofoffshore platforms. In this paper, new structural health monitoring (SHM)techniques for deepwater risers is developed to monitor damage due to vibrationand fatigue. The global monitoring is achieved using the proposed blindidentification technique based on vibrations. First, the location of thefatigue damage is determined by the proposed blind identification technique. The global monitoring is used to identify the dominant modes of vibration, fromwhich, the likely location of fatigue damage is estimated. The proposed methodis validated using Gulfstream test data from MIT. Second, extent of damage isdetermined by local monitoring using robotic crawler with magnetic flux leakage(MFL) sensor. The effectiveness of the local monitoring with MFL sensor isverified by experiments.

Combining the proposed global and local monitoring techniques can enhancefatigue damage estimation. Local inspection using MFL sensor is power efficientand yields high resolution results that can estimate the extent of damage. Proposed fatigue damage estimation technique can satisfactorily predictlocation of global damage.

The proposed SHM techniques are for well suited for deepwater risers. RoboticMFL sensor can be used for in-line inspection for pipelines. Proposed fatiguedamage estimation method can be adapted to other offshore floatingsystems.

Introduction

Risers are the most important components of offshore oil platforms. Risers arethe conduits between a subsea wellhead and a drilling or production platformfor development, production, gas lift or water injection. They can be eitherrigid or flexible. Risers can be further classified as top tensioned risers(TTR), steel catenary risers, flexible risers and hybrid risers.

Mistakes in offshore oil production can be costly; in particular riser failurehas more severe consequences. Any failure incident in the riser would not onlybe an economical and environmental disaster, but also have far reachingconsequences affecting communities. The most recent and severe accidenthappened on April 20, 2010. The Deepwater Horizon, a semi-submersible mobileoffshore drilling unit, experienced a blowout. Deepwater Horizon sank on April22, 2010 and its associated riser collapsed with the platform. 11 workers diedin the explosion. An oil leak ensued from the drill site, which leaked 4.9million barrels of oil into the Gulf of Mexico, making it the largest oil spillrecorded in U.S. history [1] (largest of its kind in the world history [2]). Although disasters of this magnitude are the result of multiple failures, advanced monitoring can be of assistance in detecting such a blowout before itoccurs. SHM systems for risers in offshore deepwater platforms are needed todetermine whether there is damage and to activate contingency plans ormechanisms to initiate damage protection measures or repairs to preventcomplete failure.
Emergency Supply of Subsea High Pressure Control Fluid Six Shooter
Authors: Lazar Stephen , Shanks Earl F. , Wacasey Brandon
Published: April 2012

An overview of the design and functionality of the Oceaneering subseaaccumulator or Six Shooter is provided. The Six Shooter was developed as asolution to the historical challenges of BOP emergency intervention. ROVtooling for subsea Blowout Preventer (BOP) intervention has been limited tosmall hydraulic pumps which require substantial amounts of time to operate BOPrams. With faster closing times recommended for emergency intervention, supplementary accumulated volume is required subsea. The Six Shooter can belaunched from a support vessel, IMR vessel or Rig, eliminating the need forcostly Rig or BOP modifications. The unit can be deployed onto a customdesigned mudmat or an existing structure.

When deployed, the Six Shooter would allow a ROV (Remotely Operated Vehicle) ofopportunity to function and provide high flow (100 gpm) and pressure (5000 psi)to the BOP via a flying lead. At these flow rates, the industry standardspecifications of 45 second ram closures can be obtained.

Equipped with dual regulators, the output pressure of the Six Shooter can beselected with the turn of a ROV valve. Depending on the number of BOP functionsthat need to be closed during an emergency situation, additional units can beeasily added with standard high flow flying leads to increase the usablevolume. The subsea accumulators are constructed with materials that allowdependable and repeatable functioning over long exposures to a subseaenvironment.

Introduction

Industry standards continue to become more stringent and require a secondarywell control system that can be accessed by the ROV, (Remotely OperatedVehicle) and is able to close critical rams in less than 45 seconds. ROV pumpsare not capable of producing the combined flow and pressures required, therefore a high pressure, high volume system is required. One option might bea complete secondary set of accumulators mounted to the BOP and controlledsubsea. However, there are restrictions on the weight of the BOP stack, andthis solution is not suitable in many cases.

Therefore, a modular independent accumulator system that can be launched andtemporarily parked on the sea floor during a drilling campaign is ideal. Thisflexibility allows the operator to forgo costly modifications to the BOP stackand drilling rig. Oceaneering has designed and built an independent subseaaccumulator system that can be deployed onto a subsea structure (mudmat, pile, existing structure, etc...) and connected to the BOP via ROV. The Six Shootercan override functions in the event topside communication is lost on the rig. This unit can be launched from a support vessel, IMR vessel, or Rig allowingany ROV of opportunity to function it. Closing times with this equipment canmatch the closing times of the original BOP stack design specifications. TheSix-Shooter module is constructed with materials that allow dependable andrepeatable functioning over long exposures to a subsea environment.
Delivering Projects during a Skills Shortage: Lessons Learned from the UK Nuclear Industry
Authors: Warwick A. , Penney John , Krishna K.
Published: April 2012

A recent Economist Intelligence Unit report on the future of the oil & gassector canvassed the views of nearly 200 board-level executives andpolicymakers on a range crucial industry affairs, from new investmentopportunities to future regulatory challenges and the rise of a new breed of'internationalized' national oil companies over the next decade.

One of the key findings from the subsequent round table discussion (facilitatedby GL Noble Denton) was that more needs to be done to develop the nextgeneration of oil and gas professionals. Faced with a period of investment andexpansion, the sector will come against challenges as a result of its failureto attract, recruit and retain highly talented people. The discussion concludedthat the industry needs to work more closely together to address the skillsproblem, rather than trying to pursue each others' technical staff. Withactivity set to rise in the sector, companies need to focus on introducing anddeveloping technical resource now, ensuring that the right talent is in placefor the future.

Atkins has been helping the UK nuclear industry to overcome similar challengesin recent years.

The UK nuclear supply base had been gradually declining over the last 20 yearssince the completion of the last power station at Sizewell. This has beencompounded by the hold placed on the deep waste repository and the prolongedhiatus between the Vanguard class submarine program and the Astute classSubmarines in the defense sector. This has led to government concerns that theUK capability would not be sustainable, with many of the current UK nuclearsupport needs more design and major project related than the consultancy typework of the last two decades. This requires a greater focus on technicalassurance and process compliance to ensure that project delivery and qualityrisk is managed appropriately.

This paper outlines the processes that Atkins is using to increase staffnumbers and develop its in-house technical expertise in response to the currentand anticipated needs of the UK nuclear industry; whilst at the same timeensuring technical quality is maintained and project delivery risk isminimized

Introduction

The UK supply base had been gradually declining over the last 20 years sincethe completion of the last UK nuclear power station at Sizewell, compounded bythe hold placed on the deep waste repository and the prolonged hiatus betweenthe Vanguard class submarine program and the Astute class Submarines in thedefense sector.

Over this period of time the industry has fragmented with the tier 1 providersoutsourcing much of their capability and reducing their core business torelatively small enterprises. This has led to a growth in small and medium sizeenterprises providing manpower substitution and specialist services to the tier1 providers. The current status of the supply base led to government concernsthat the indigenous UK capability would not be sustainable without significantinvestment.
Acid Gas Dehydration - Is There a Better Way?
Authors: Mckay Wayne , Maddocks Jim
Published: April 2012

Today, when acid gas containing significant amounts of carbon dioxide isprocessed for sequestration or EOR reinjection, it is typically dehydrated witha glycol absorption process. Three dehydration processes are examined by way ofan example case. The examination includes financial, physical, environmental, process, and operational comparisons. Pros and cons of the currently availableoptions are discussed and the paper demonstrates why glycol absorption is thethird best option for most applications - especially offshoreapplications.

To establish a baseline of understanding for acid gas dehydration processes, this paper first outlines why, when, and how much acid gas dehydration isrequired and relates that to current guidelines. The paper introduces adehydration method that is lower in both capital and operating cost, issignificantly smaller, has almost no emissions, and is easier to maintain thanthe alternatives. The first commercial installation of this technology went onstream in February 2011 at a 180 MMscfd natural gas processing facility inWestern Canada.
Marlim 3 Phase Subsea Separation System - Challenges and Solutions for the Subsea Separation Station to Cope with Process Requirements
Authors: Orlowski Rene , Euphemio Mauro Luiz Lopes , Euphemio Mauro Lopes , Andrade Cynthia Azevedo , Guedes Flavia , Tosta da Silva Luis Carlos , Pestana Rafael Guimaraes , de Cerqueira Gustavo , Lourenço Igor , Pivari Alexandre , Witka Anderson , Folhadella Heloisa , Pacheco Leonardo , Kronemberger Steven , Vilela José
Published: April 2012

This paper presents the experience brought from the oil-water subsea separatorproject developed for the Marlim field, known as SSAO Marlim. Here, it will beaddressed the inherent arising challenges from a project of a subsea separationequipment, from the subsea mechanical design perspective, with special focus tothe additional requirements to the normally presented in conventional subseaequipment for oil and gas production.

It will be part of the discussion the architecture selected for the system andthe main challenges imposed by:–Separation process (gas-liquid, liquid-liquid and sand removal system);–Requirements for modularization, installation and retrieval of subseacomponents;–Installation concept.

Introduction

The oil-water subsea separator is installed in a water depth of approximately870m in the Marlim field, located in the Campos basin, Brazil. The subseaseparation station has an envelope of 29m length, 10.8m width, 8.4m height andan overall assembly weight in-air of 392ton, and it will receive productionfrom selected well, separate produced water from oil and sand and re-inject itinto Marlim production reservoir via a centrifugal pump. The water separationhappens into a Pipe SeparatorTM based on a gravitational concept, while waterpolishment to meet quality requirements, i.e. reduce oil content in water toacceptable levels for the re-injection into reservoir, is performed by cyclonicequipment. The equipment also has a sand management system which the main aimis to minimize the operational impact induced by solids production.

Figure 1 illustrates the oil-water subsea separation system of Marlim.
Floating CNG, A Simpler Way to Monetise Offshore Gas
Authors: Stenning David G. , Fitzpatrick John P. , Trebble Mark A.
Published: April 2012

Monetizing offshore gas by compressing and shipping in CNG carriers (FCNG) issimpler and in most cases, less expensive than liquefying and shipping in LNGcarriers (FLNG). Seaborne CNG transport requires essentially the sameinfrastructure as pipeline export, except that the gas is compressed into aship rather than a pipeline.

Significant investments are being made in engineering and implementing FLNGsystems. These FLNG systems are generally aimed at large field developments.FCNG provides a new way to add to the world's natural gas supply by allowingsmaller offshore gas fields to be economically exploited.

The key to making FCNG a robust and general solution for offshore gasexploitation is the availability of internationally approved CNG ships that canoff-take the gas and deliver it economically to markets within 2500 km. Theseapproved CNG ships are now available.

The paper will describe the major components of an FCNG system including thecapital and operating costs. It will also outline the principal advantages ofsuch a system compared to an FLNG system.

Introduction

Many offshore gas fields are too small or too remote to produce by pipeline toshore. The LNG industry has advanced to fill the need in respect of larger gasfields by creating an FLNG production concept where an LNG processing andrefrigeration plant, complete with LNG storage, is integrated into a ship orbarge and moored at a gas field. LNG ships are then used to offtake the LNG anddeliver it to markets, where it is stored and regasified as needed. FLNGprojects have many technical and economic challenges, and the recentannouncement of Shell's final investment decision for the Prelude FLNG projectis a testament to the work and commitment that the industry has invested inFLNG. However, a simpler and less expensive way to produce gas from many fieldsis to avoid liquefaction altogether and instead just compress the gas into CNGships, which then deliver it to regional markets. Marine CNG serves marketsthat fall between subsea pipeline markets and long distance LNG markets.
SS-Offshore Offloading Systems and Operations Bonded Flexible Oil Offloading Lines, A Cost Effective Alternative to Traditional Oil Offloading Lines
Authors: prischi Nicolas , Mazuet Francois , Frichou Adeline , Lagarrigue Vincent
Published: April 2012

In deepwater offshore fields where spread moored FPSOs are involved, theproduced oil is generally offloaded to shuttle tankers via Oil Offloading Lines(OOLs) connected between the FPSO and deepwater buoy. Until recently, two typesof Oil Offloading Lines (OOL) were used for the transfer of stabilized crudeoil between the FPSO and the offloading buoy: steel pipe or unbonded flexiblepipe. Since 2000 Trelleborg and SBM have been working on an alternativeoffloading solution made of bonded flexible hoses called TRELLINE™ (seereference [1]). This product can be adapted to a large range of applicationslike for the offloading of oil from a MOPUstor to a submerged loading system(SLS).

In September 2005, the TRELLINE™ was used for OOL for the first time for SNEPCOwho decided to supplement the existing Bonga OOL system with one 20" IDTRELLINE™ to match with ultra short delivery. In December 2006, the OOL wasinstalled with the SBM vessel Dynamic Installer (see reference [2]).

In July 2008, Total Exploration Production Angola (TEPA) decided to use theTRELLINE™ for the 18" ID OOLs of the Pazflor field. For Pazflor, the producedoil is exported from the FPSO to the buoy located 1,856m away, via twoidentical 18" OOLs of 2,070 m long, made of 175 hoses sections each. The OOLsare connected to the FPSO and the buoy by the means of gimbal tables thatdecouple the tension and bending loading. Specificity of Pazflor Trelline hoseswas their hig desing pressure equal to 50 bars that had required intensivequalification and testing program, and making Pazflor export lines a" world-first".

Based on past installation experiences on Bonga project (OOL) for SNEPCO in2006 and on Yme project (SLS) for Talisman Energy Norge in 2008, see reference[3]), a new installation method has been developed. A specifically designedpatented equipment was developed to ensure a safe and quick offshoreinstallation.

It comprises:An A-Frame designed to upend individual hose from deck to the fireline.An assembly platform designed for vertical assembly of the hoses.A large deployment wheel ensuring the transition from vertical to horizontalof the OOL at the sea surface.

In June 2011, the SBM vessel Normand Installer successfully installed the twoPazflor OOLs. The two OOLs were assembled and hooked up in less than 4 weeks(mobilizations included).

The TRELLINE™ OOL system demonstrated its advantages in term of design, procurement cost, lead time, installation efficiency and operationaladvantages. It will further demonstrate maintenance advantages.
Sand Face Completions Enter the Real Time Age with a One-of-a-Kind Downhole Visualization Tool
Authors: Grigsby Tommy F. , Jannise Ricki C. , Schwendemann Ken , Rubio Raymond , Towers Darrin
Published: April 2012

The operation of downhole sand-face tools has relied upon depth measurements, downhole indicators that use applied tension or compression noted on thesurface weight indicator, as well as hydraulic pressure in order to verifyservice-tool positions in relation to the sand-face assembly. This strategy hasworked well in the past. However, with field developments with increasing welldepths, higher-angled wells with increasingly complex geometry, and increasingintricacy in sand-face tool systems, the need for additional methods to aidtool operators in locating and communicating service-tool positions has becomeapparent. Also, modeling the effects of the pumped treatment on the tool systemand work string in real time will assist in understanding when, and if, thetool system will move out of position.

The introduction of multiple-zone one-trip sand-face completion systemsdeveloped for applications in the ultra-deepwater Lower Tertiary play of theGulf of Mexico has led to the development of a visualization tool that providesthe tool operator with additional information to validate conventionaltool-locating methods as well as providing a communication interface tocommunicate the tool information to others. This innovative visualization toolis a software program known as the " Real Time Visualization Service (RTVS)". The RTVS package provides detailed visualization of the entire sand-faceassembly, including the service string, providing the tool operator andobservers with another tool-location validation method along with anexceptional pre-job planning tool. The visualization software provides thecapability to monitor operations at the rig site or remotely from a real-timemonitoring site or home personal computer.

Introduction: Development Drivers for Real Time DownholeVisualization

There are a number of factors that have converged to drive the development ofthe real time downhole visualization capability. First, well depths and welldeviations are increasing. The Lower Tertiary play in the Gulf of Mexico haspotential well depths to 33,000 feet while other areas in the Deepwater GoldenTriangle (Brazil & Angola) (Gue, 2009) use horizontal sand face completionswith increasing horizontal lengths. Second, sand face completions have becomeincreasingly complex as interval lengths have increased and intervalsegmentation is required to effectively stimulate the reservoir. Third, thehigher rig rates for deepwater have highlighted the need to reduce work stringtrips and time by using tools that are multi-functional, adding furthercomplexity.
Slickline-Retrievable Wellhead Plugs and Downhole Plugging System Provides Wellbore Integrity for Extreme HPHT Environments
Authors: Pickle Brad , Swan Tom
Published: April 2012

Trends in offshore exploration continually push the definition of high pressureand high temperature in regards to oil and gas well completions. Recentdiscoveries in the Gulf of Mexico (GOM) are opening up vast reserves of naturalgas and these discoveries are again challenging that definition. To meet theneed of high-pressure, high-temperature (HPHT) applications in general and foran operator in one such HPHT field, an ultra high-pressure and high-temperaturerated wellhead plug and downhole plugging system has been developed to providewellbore integrity in extreme conditions.

This paper addresses the challenges associated with development ofslickline-retrievable equipment rated to 25,000 psi at temperature extremesfrom 32°F to 450°F and the approaches used to overcome those challenges. Areview of design considerations, sealing technology, design verification, andvalidation testing that exceeds industry standards, is also provided.

Introduction

While the industry is rising to meet global demands for energy, the reservesneeded to fill that demand are increasingly in more challenging geologies suchas deeply buried reservoirs. Drilling to unprecedented depths is opening a newfrontier of pressure and temperature extremes. To appreciate the growth ofactivity in deeply buried reservoirs, according to the Energy InformationAgency, deep gas production in the US in 1999 was 7% of total production and in2010 an expected rise to 14% of US total gas production. In another industrystudy, the number of HPHT wells drilled from 1982 to 2010 was just over 300wells, while the forecast from 2011 to 2019 was to increase that total to over900 wells with a global geomarket distribution.

For many years, HPHT was commonly defined as 10,000 psi pressure and 300°Ftemperature or greater. The move into these new frontiers has moved beyond thetraditional definition of HPHT. One such classification structure is shown herein Table 1 with three levels of HPHT regimes. It is the move into the extremeand ultra HPHT regimes that is driving new methodologies of analysis andvalidation to ensure wellbore integrity in these very challengingenvironments.

As the scope of HPHT has expanded, the challenge facing the industry is how toprovide for wellbore integrity under such extreme conditions. This was thechallenge for one service provider to design and develop a wellbore pluggingsystem from the wellhead down to the bottom of the production tubing. To thisend, a unique landing nipple and slickline deployed plugging system wasdeveloped specifically for HPHT, capable of operating in all three regimes. Thenipple and plug system discussed in this paper was developed for a project inthe GOM and is rated to 25,000 psi and 450°F. The plugs incorporate a pumpthrough capability while also accepting a prong to convert to a positive plug. Key operational issues to minimize risks were also addressed.
Developing Process Safety Capabilities in New Engineering Graduates
Authors: Kim B.K. , Mentzer Ray , Mannan M.S.
Published: April 2012

Various major oil & gas incidents are constant reminders of the importanceand distinction between personnel and process safety. While the North Sea PiperAlpha disaster had a serious impact on both onshore and offshore operations, the more recent US Gulf of Mexico Deepwater Horizon incident has resulted innew regulatory requirements. The new Safety & Environmental ManagementSystem (SEMS) regulatory requirement emphasizes both process and personnelsafety aspects in Outer Continental Shelf (OCS) oil and gas operations. Whileprimarily a voluntary requirement since the mid-90's, effective November 2011, it has become mandatory. Consistent with industry's focus on process safety, training in process safety is now a mandatory requirement in ChemicalEngineering curricula starting in 2012. Academia has a significant role inimproving process safety and personnel safety by proving training and educationfor new engineering graduates, as well as the current workforce. In addition, advanced research programs can help close current gaps in the understanding ofprocess safety and ultimately improving safety performance of the OCS oil andgas operations. Such studies include safety culture, fires & explosions, facility layout optimization, inherently safer design, and pipeline corrosion, to name just a few areas.

1. Introduction

Process safety has become one of the inevitable elements in keeping businessesin various industries sustainable. Various industries have suffered painfullessons from incidents and have taken steps to prevent similar tragedies fromreoccurring. The Bhopal incident in 1984, which caused +2,000 fatalities, andthe more recent Deepwater Horizon incident, are a few examples which show thecatastrophic impact of process safety related incidents. Although eliminatingrisk entirely is not feasible, recent progress in process safety has improvedsafety performance through recognizing the risk and implementing safetymeasures to prevent or mitigate catastrophic consequences. This paper describesthe implementation of process safety in the offshore oil & gas industry, the new regulatory requirements, and discusses the training of engineers andresearch to promote safer operations.

2. Process Safety in Offshore Oil & Gas Industry

2.1 Development of Process Safety

The worst chemical disaster, the Bhopal MIC release in 1984, triggered newcomprehensive regulations in the US chemical industry [1]. Prior to the Bhopalincident, a systematic approach to understand the phenomena regarding processsafety had not been well established, but rather, case studies were conductedfor each incident. Following the Bhopal incident, the Emergency Planning andCommunity Right-to-Know Act (EPCRA) of 1986 was passed by the US Congress. ThisAct promotes emergency planning for potential chemical accidents and providescommunities with proper information on potential hazards imposed by thechemical processes [2].
Invited Organization: Marine Electromagnetic Methods for Gas Hydrate Characterization
Authors: Weitemeyer Karen Andrea , Constable Steven
Published: April 2012

Motivation

Natural gas hydrates are a potential energy resource and a geohazard fordrilling and submarine infrastructure. Estimates of the global volume of gashydrate vary by over many orders of magnitude. Mapping the spatial distributionof gas hydrate deposits can be difficult using only seismic methods. Oneseismic signature is a bottom simulating reflector (BSR) which indicates thelower limit of the stability field, typically marking the gas hydrate to freegas boundary, but provides little information about the occurrence of gashydrate above it. Seismic blanking zones denote hydrate or gas only at shallowdepths below the seafloor. Another physical property of gas hydrate is that itis known to be much more resistive than seafloor host rocks. Recent laboratorymeasurements on unmixed CH4 hydrate (i.e. no sediment) confirms that hydrate isless conductive (10–5 to 10–4 S/m) than seawater (~ 10–1 to 101 S/m), providinga resistive target for marine controlled source electromagnetic methods (CSEM)(DuFrane et al., 2011). We have applied "standard" marine controlled-source EM(CSEM), and have been developing towed EM receivers to increase the density ofcoverage at fixed source-receiver offsets. A pilot study at HydrateRidge, offshore Oregon, illustrated our ability to distinguish between free gasbelow the seismic BSR (the edge of the hydrate stability field) and hydrateabove, and a more comprehensive study of 4 sites in the Gulf of Mexicodemonstrates our ability to image a variety of near-surface geology.