bluuebunny/crossref_metadata_2025 huggingface dataset:
Typhoon Steel Catenary Risers: As-Built Design and Verification
Authors: Thompson H.M. , Grealish F.W. , Young R.D. , Wang H.K.
Published: October 2008

The Typhoon 18" Gas Export Riser has the lowest water depth to diameter ratio of any installed riser to date, resulting in an extremely challenging fatigue design at the seabed touchdown point. Uncertainties related to the analysis and design of SCRs are particularly highlighted for this riser because the fatigue life is so close to design limits. This paper describes the as - built design of the riser by Stress Engineering Services (SES), and the as -built verification performed by MCS International. Even after the two analyses incorporating as-built field data were completed, the design and verification results showeddifferences that put the design either above or below the target fatigue design life. Areas of similarity between SES and MCS analyses are first described, including cross section modeling, TLP motions and offsets, hydrodynamic coefficients, S-N curves, and fatigue damage calculation method. Next, the primary areas of difference between the SES and MCS analyses are described, including touchdown point modeling and 3D drag linearization. Discussion of the state of practice of touchdown point modeling as it relates to SCR fatigue calculation is given. The paper concludes with a summary of lessons learned during the design and verification of the Typhoon SCRs.

1.0 Introduction

The Typhoon Field is located in Green Canyon Block 236 and 237 in approximately 2,100-ft water depth. The TLP is owned y BHP and ChevronTexaco, with ChevronTexaco the designated operator. The discovery well was drilled in April, 1998 and the project sanctioned in January 2000 for the development of 4 subsea wells produced to a centrally located TLP. Flexible risers are used for the production wells. A 10" oil export SCR and 18" gas export SCR are used for product export.

The verification section of this paper will focus on the 18" gas export riser. At the time of installation the 18" gas export riser had the smallest water depth / diameter ratio of any installed SCR, resulting in an extremely critical fatiuge life at the SCR touchdown point.

2.0 As-Built Vs. Design by Stress Engineering

Design

Stress Engineering Services (SES) was part of the Typhoon SCR design team and was responsible for the design analysis including initial sizing and detailed analysis for environmental conditions. The analysis provided design parameters including SCR shapes, extreme and cyclic loads for designing the SCR porches and flex joint receptacles, and extreme and cyclic angles for designing the flex joints. Fatigue analysis not only provided an evaluation of the expected life of the SCR's but it also identified target SN curves to be qualified by testing of the welds and provided histograms of stress ranges for the fracture mechanics analysis used to establish automatic UT (AUT) acceptance criteria for the actual installation welds. The fracture mechanics analysis was performed by Hsu (February, 2001).
Low Cost Anchor System for Flexible Risers in Deep Waters
Authors: Medeiros C.J.
Published: October 2008

In order to avoid that the loads generated by the floating units movements be transferred through flexible risers to subsea equipment, significantly additional flow lines length have been used to absorb those loads by line/soil friction. Due to the high costs of these lines, Petrobras has developed a new anchor system concept to fix the risers on the seabed, in lieu of increasing flow lines length. This anchor system, called "Torpedo", consists of a pipe pile filled with scrap chain and concrete, close ended with a cone tip, installed by free fall from a vessel, and connected to the risers with a special system operated by ROV. Bundle of three risers have been anchored by each pile with holding power of 1400 kN.

Taking advantage of the experience in this pile design and installation to anchor risers, larger free fall piles with holding power up to 7000 kN have been designed and already certified to anchor floating units.

This paper aims to present an overview of the design and installation procedures, cost estimation, field and model tests results and applications of the Topedo Anchor System.

Introduction and Background

Flexible risers are anchored on sea bed by means of drag anchors or plates, gravity structures and piles which may be installed by driving, suction or drilled and cemented in.

Because of the high costs of these anchoring method for deep water, since 1996 Petrobras has developed the technology of free fall piles to be installed in soft clay to anchor flexible risers and floating structures.

To evaluate the costs and performance of this solution, in house softwares have been developed and full scale in situ tests have been performed in Campos Basin (see Fig. 1). Model tests (see Fig 2), with different weights and shapes were made in laboratory, in order to optimise the torpedoes design.

Torpedo Anchor Characteristcs

The torpedoes designed to anchor flexible risers is a 30" OD pipe pile, twelve meters long, filled with scrap chain and concrete (see Fig. 3). It has a dry weight of 240 kN and a holding capacity of 1400 kN. The pile/mooring line connection has an internal padeye underneath a guide that allow the anchor load to be applied in any direction. With these characteristcs, it has been used to anchor a bundle of three risers up to 12" of diameter in 1300m water depth.

Torpedoes Anchors with that same 30" OD tube twelve meters long, ballasted with heavier material and provided with four vertical fins (0.45 m × 9 m), are being fabricated to anchor MODU's (Fig. 4). To anchor Floating Production Systems (FPS) with a required holding capacity of 7500 kN, torpedoes designed with 42" OD tube, fifteen meters long, dry weight of 950 kN, and provided with four vertical fins (0.90 m × 10 m), are being manufacturated.
The Accident of P-36 FPS
Authors: Barusco Pedro
Published: October 2008

The semi submersible platform P-36 was operating in Roncador Field, in Campos Basin, producing 84.000 bopd, with capacity to reach the peak production of 180.000 bopd. On the 15th of March of 2001 an accident took place on board of the unit causing the death of 11 crewmembers and the sinking of the platform five days later.

An inquiry commission was formed just after the accident in order to investigate the causes and set up recommendations in order to prevent similar events.

This paper describes the methodology applied by the commission during the investigation phase, the work developed by them, what happened on board on that day, the conclusions about the main causes which led to the sinking of the unit and the recommendations addressing design, operation and safety of floating offshore units.

The results, conclusions and recommendations relative to this accident were used by Petrobras as bases to create a program inside the company called Operational Excellence Program whose main goal is to implement several actions toward increasing of the safety of offshore operations.

As for Petrobras, the information disclosed in this article can help other oil companies improve their HSE programs.

The detailed description of the events which took place the moment of the accident until the sinking, the main causes, conclusions, observations and recommendations of the inquiry commission and a general picture of the content of the Operational Excellence Program of Petrobras are addressed by this article.

Description of the P-36 platform

The P-36, formerly called "Spirit of Columbus", was a floating production unit (FPU) based on a conversion of a Friede & Goldman L-1020 Trendsetter type semi submersible platform. It was initially designed and built, in Italy, as a FPU to operate at 500m water depth, with a capacity to process 100,000 bopd and 2 million cubic meters per day of gas. The design and construction began in 1984 and ended in 1994.

The field, which it was intended to produce, did not prove to be commercial during the development phase. As a consequence it was offered to Petrobras that analyzed the possibility of converting the unit to produce in Campos Basin. After the evaluation for use in Marlin South and Roncador fields, Petrobras decided to select the unit to be the first FPU of the giant Roncador field.

The main modifications done during the conversion phase were: complete substitution of the process plant, installation of a new power generation plant, removal of the drilling equipment and propulsion system, changing the mooring system and increasing the payload by the addition of stability boxes in the pontoons and blisters in the columns.

After the conversion, which lasted from September 1997 to October 1999, the platform had the capacity to produce 180,000 bopd, to handle 7.2 million cubic meters per day of gas and could be installed at water depths around 1500m.
Roll Minimization by Blige Keels and Moving Weight Systems
Authors: Vassilopoulos Lyssimachos
Published: October 2008

The objective in this paper is to discuss the technical and economic considerations arising in the process of minimizing the roll motion of marine vehicles through the use of bilge keels and moving weight systems .. Given a statement of the mission and owner';s requirements for any vessel, the procedure for selecting the most appropriate anti rolling device is delineated on the basis of a trade-off analysis among candidate systems for such an application. Design methods are developed for moving weight systems and bilge keels on the basis of linear and nonlinear mathematical models of the interacting ship-stabilizer motions. The paper concludes with the description of a computer program developed for stabilizer design, some example applications and a brief review of the economic advantages accrued by the incorporation of roll stabilizers.

INTRODUCTION

During the last decade, the maritime industry has witnessed an impressive trend toward the deployment of "roll stabilizers" onboard different types of marine vehicles. Contrary to what their name might imply, the function of such systems is to minimize or suppress a vessel';s roll motion, rather than enhance its transverse stability. Typical anti rolling devices range from the time-honored bilge keels to sophisticated fin arrangements and activated tanks, each providing a differing roll reduction effectiveness depending on the particular application.

Unlike other ship motions, roll is readily susceptible to containment, mainly because the inherent damping properties of most hulls are low and also because the external couples acting on the vessel are not too excessive. Under such conditions, it becomes relatively easy to conceive of a system that produces, at the expense of a small amount of energy, the appropriate torque counteracting that induced by the environment. The required energy may either be extracted from the rolling vessel itself, as in the case of passive anti rolling systems or may be supplied externally by separate sources, as in the case of activated devices.

The question of whether a given vessel should be equipped with one or more anti rolling devices cannot be answered objectively unless a study is made of her dynamic behavior in the expected environment, given the mission objectives and hull characteristics. The first step in such a study is to attempt to define critical measures of roll (or its time derivatives) which can be used as yardsticks of what constitutes acceptable roll behavior, Ref. (1). The second step is to find how the vessel behaves in a variety of operational conditions and to judge whether her responses are acceptable. If they are, the question of stabilization is by-passed. If they are not, the third step is to examine whether certain changes in geometry and mass distribution might reduce roll.
Girassol: The FPSO Presentation and Challenges
Authors: Bang Pierre
Published: October 2008

While the history of floating production storage and offloading (FPSO) is paved with record cost overruns and delays, through the description of the Girassol FPSO project, this paper presents the ways and means used by the Operator-TotalFinaElf - to manage the successful development of the world's largest deepwater FPSO installed in the Girassol field, offshore Angola.

The Operator, in developing the FPSO, employed parallel engineering, functional specifications and an early involvement of the industry with an original contracting strategy in order to achieve the Girassol field development in less than six years from discovery to first oil setting a new standard for the Industry.

The FPSO described here is now the only visible facility of this pioneering project for the offshore industry (Figure A-1).

Introduction

Discovered in April 1996, the Girassol field development was sanctioned two years later in July 1998 based on a subsea production scenario associated with a large FPSO, having the following main characteristics:Oil storage: 2,000,000b/dOil Production: 200,000b/dLiquids treatment: 300,000b/dProduced water treatment: 180,000b/dWater Injection: 390,000b/d at 150 barSeawater Sulfate Removal : 400,000b/d < 40 mg/lGas injection: 8,000,000Sm3/d at 285 bar

On December 4, 2001 the world's largest FPSO produced first oil from subsea wells through a subsea production system (SPS) and umbilical flowlines and riser towers (UFL) from the 1,400m water depth at the Girassol field.

Sailaway of the FPSO from the construction yard in South Korea occurred at the end of March 2001 at a level of completion and commissioning never achieved before for a production unit of such complexity. The completion, just 33 months after the award of a contract based on functional specifications, constituted a new benchmark for future FPSO's. The hull construction subcontract was performed in 19 months and the construction of the 25,000tonnes topsides subcontract was done in 21 months.

The initial "fast-track" approach of the Girassol development required the FPSO execution to face the following challenges :Parallel reservoir engineering and surface facilities development;Interface data issues due to different schedule in design development between UFL and FPSO;Management of significant design data changes in throughput and treatment capacity during contract execution;

Additional challenges to the FPSO development came from the following adverse events which occured during the course of the project execution:Very buoyant shipyard market;Reallocation of topsides construction and integration site.

From the first months after discovery, the Girassol FPSO development history described here presents how the Operatorand its Contractors, through the contracting strategy, the main architectural choices and project execution, faced these challenges and managed the successful FPSO development, crowned by first oil 41 months after project sanction.
Modelling Risk and Safety Systems of Deep Offshore FPSO/Pipeline System
Authors: Abhulimen K.E. , Susu A.A.
Published: October 2008

This paper presents a model that captures the risk and safety systems of a deep offshore FPSO/Pipeline system. The overall risk and safety function of the FPSO/Pipeline system was hierarchically determined as a universal set of sub risk systems, using a modified fault tree analysis and FMECA (Failure Mode Effect Critical Analysis) to establish the cause of failure and evaluate its potential. The transient state behaviour of the risk and safety systems of the FPSO/Pipeline system was modelled using the markov chain process. The results of simulation of a typical FPSO-Pipeline sub system, shows that a model suitable for analysing the risks and safety behaviour of complex multifunctional FPSO/Pipeline system has been developed. The inclusion of a weighting function in the model to assign a relative importance of a risk or safety event in several interacting risk systems represents an important deviation from other benchmarks. The concept of weighting function relies on the experience of the user to assign different weights to different risks or safety in a given environment. This allows the possibility of evaluating the impact of different risks on the reliability of multifunctional systems

Introduction

There are many methodologies proposed for reliability, risk and safety analysis for most, if not all process industries known today. Among the most popular ones, are quantitative risk analysis, probabilistic safety analysis, and worst-case methodology for risk assessment and optimal risk analysis. The optimal risk analysis (ORA) appears to be the most suitable, as it is fast, less expensive to implement, less time consuming and more precise than alternative analysis (1, 2). ANSI/ISA S84.01-1996 is the consensus standard for process safety in the U.S, deemed to meet the OSHA 1910.119 PSM regulation (3).

Three methodologies are proposed in the TR84.02 report to be published by ISA (4). They are simplified equations, Fault Tree Analysis, and markov modelling to implement the safety performance requirements of the standard, for the SIS. The standard requires that the average probability failure on demand (PFDavg) be used in this analysis (5,6).

Khan, F.I, and S.A Abassi (1) have presented a critical review of these methodologies. While the benefits of these methods have been well demonstrated in many publications, it appears that the development of a model that captures the intrinsic behaviour of the risk and safety systems of typical complex multifunctional system like the FPSO/Pipeline system have not been sufficiently researched. The problems are normally associated with complexity of the interacting components and process hazards that could lead to failure (7).

Our paper therefore, presents a model that incorporates the use of a weighting function to capture the complex risk and safety behaviour of the interacting components of the subsystem of typical FPSO/Pipeline system. A common misconception is to assume that a system prone to fewer risks is safe.
An Overview of the Na Kika Flow Assurance Design
Authors: Hudson J.D. , Dutsch D.B. , Lang P.P. , Lorimer S.L. , Stevens K.A.
Published: October 2008

The Na Kika project is among the most complex subsea developments attempted by our industry and faces a number of unique flow assurance challenges due to the extreme water depth (5800 to 7600 ft), distributed well layout, variability in produced fluids (from six distinct fields), offsets of up to 26 miles and relatively low temperature reserves. Flow assurance provided key drivers to subsea system selection and definition and was an important aspect of assessing project profitability. This paper gives an overview of well and subsea system features and describes the flow assurance strategies and the unique operations that will be required for successful operation at Na Kika.

Project Characteristics

The Na Kika project consists of six oil and gas fields in the Mississippi Canyon area of the Gulf of Mexico. Water depths range from 5800 to 7600 ft. The individual fields in the Na Kika base development are Ariel, Kepler, Fourier, Herschel, and East Anstey, each of which will be developed as subsea fields with produced fluids routed back to a floating host roughly located in the center of the development area. Coulomb is currently being developed as a near-term addition of reserves, which will likely be produced by a single flowline back to the Na Kika processing facility. Offset distances from the host are in the range of 5 (Ariel) to 26 miles (Coulomb). The general arrangements are as according to Figure 1.

The Na Kika subsea layout consists of a single, 10" × 16" pipe-in-pipe flowline loop for those fields north of the host (Ariel and Kepler), as shown in Figure 2. On the south side, there are two flowline loops, an 8"x12" pipe-in-pipe insulated oil loop for the Herschel and Fourier wells, and an 8" uninsulated gas loop for the East Anstey and Fourier wells (see Figure 3). The subsea system at Fourier includes the flexibility to allow the clustered wells to produce back through either the gas or the oil flowlines, via well jumper reconfiguration. This subsea architecture deviates significantly from previous projects through the use of flowline loops, as opposed to dual lines to a manifold, and the use of a single flowline for the relatively rich Coulomb gas wells.

The key input into the flow assurance process is the proper acquisition and analyses of fluid samples. In the case of system selection for Na Kika, fluid samples are available from at least one exploratory well from each of the individual fields and, in the cases of Ariel and Fourier, from subsequent appraisal wells. The analysis of these samples has been used in the flow assurance work described in this paper. There remain, even at this point, some uncertainties about key fluid properties, such as salinity and asphaltene stability. These uncertainties have been considered in the analyses and have been used as a basis for future sampling efforts for the development wells.
Girassol Export Lines
Authors: Tricard Paul , Hattet Denis , Leijnse Rorik , Seng Dominique
Published: October 2008

This paper will describe the development of a new pipeline concept for the export of oil from a large capacity FPSO to an offloading buoy. The installation of the two ‘w’ configuration rigid steel pipelines, carried out successfully by the Saibos ConstruÃ§oes Maritimas Lda's new deepwater installation vessel Saibos FDS was particularly adapted for deep and very deep-water field developments like Girassol in 1,400 meters.

Details of the concept will be covered with a major focus on the innovative installation method.

INSTALLATION of GIRASSOL EXPORT LINES:

In early November 2001, the Saibos FDS (Field Development Ship) successfully installed the two 16in rigid export lines that link the Girassol FPSO with its loading buoy.

This installation was a first for several reasons. It was the initial installation of rigid pipelines by the newbuild state-ofthe-art installation vessel as well as being the first time that a midwater steel catenary riser (SCR) type export line solution has been used in an offshore oil field development.

The challenging water depth of the Girassol field (1,400m) combined with the relatively close proximity of the loading buoy - roughly 1,800m - mitigated against a conventional installation of carbon steel export lines on the seabed. An alternative solution should have favoured the use of flexible pipe, but cost was a factor. After much analysis, Alto Mar Girassol (AMG) proposed this innovative rigid pipeline solution which was found both technically feasible and more cost effective.

The initial concept suggested to TotalFinaElf E&P Angola by the AMG joint venture, in which Bouygues Offshore (BOS) was responsible for the installation of the two export lines, was a conventional subsurface tow and connection to the FPSO of the two strings. This installation method was later abandoned when it became apparent that installation by j-lay resulted in a significant improvement in the fatigue life of the export lines.

The use of this installation method was an option as Saibos, the joint venture between Bouygues Offshore and Saipem, was building a new dynamically positioned (DP) vessel which has among its features a j-lay tower adjustable between 45° and 96°.

This paper will summarize the challenge of this installation together with the main characteristics of the export lines and the features of the new vessel.

EXPORT LINES PRINCIPLE:

The two 16in export lines are configurated like a subsurface "w" between the bow of the FPSO and the loading buoy located under 2km to the northeast (Figure 1). The lines are supported at the FPSO via two receptacles, located on the port and starboard sides, in which flex-joints were pre-installed on the lines and through which the lines were pulled in.

The starboard line is the "upper" one with the branches of the "w" located in a water depth of 440-530m and has an overall curvilinear length of approximately 2,400m. The port side or "lower" line, is suspended in a water depth 630-740m with an overall curvilinear length 2,750m.
Girassol: Design Analysis and Installation of the Suction Anchors
Authors: Dendani H. , Colliat J-L.
Published: October 2008

Suction anchor piles are the main foundation and anchoring system for the Girassol development in 1,400m water depth, including the FPSO, the offloading export buoy, the riser towers and the subsea manifolds.

This paper summarizes the main assumptions in the geotechnical design analysis, together with key features of installation behavior. Based on installation results, a revised method for the penetration analysis is proposed. The Girassol experience will be relevant for future applications of suction anchors at other deepwater locations in West Africa.

Introduction

For the permanent mooring of production floaters in waters over 1,000m, taut leg moorings are used, i.e. at an angle ranging between 35° and 45°at mudline, with steel wire cables or fibre ropes and with anchors having a vertical loading capability. In the soft clays generally found at deepwater sites, suction anchors and vertically loaded plate anchors (VLA) have become the two preferred options.

A significant number of applications for the suction anchor have been found due to the following advantages [1]:fixed location on seabed, which is important in congested subsea field developments;simple installation procedure with no need for proof-load testing; andreliable design methods for ultimate capacity calculation, providing a larger confidence in their long term pull-out capacity.

The Girassol field, the deepest offshore development off West Africa to date, is located in about 1400m of water in Block 17 operated by TotalFinaElf EP offshore Angola. The Girassol FPSO is connected to 40 subsea wells by means of three-riser towers and pipeline bundles [2]. In relation to the suction anchors, the installation operations took place between March and August 2001 and were carried out by Alto Mar Girassol (AMG) and Mar Profundo Girassol (MPG)), two consortia of Stolt Offshore and Bouygues Offshore Serviices, and SBM, from the crane barge Seaway Polaris and the vessel Seaway Eagle.

Girassol Seabed and Soil Conditions

From high-resolution 3-D seismic and shallow geophysical data, the Girassol seabed appears as sloping gently to the southwest, with a gradient of about 1:50 (1.2°). The soil investigation campaign carried out at the Girassol field comprised:four borings taken down to 30m with alternative push sampling and cone penetrometer testing (CPTU), with one boring at the site of each group of four FPSO anchors;three 30m deep borings, with combined sampling and CPTU testing, covering the subsea well locations over an area of about 8km by 7km;one 100m deep central boring for designing the penetration depth of the well conductors;two 30m deep continuous CPTU profiles, performed at a riser tower and FPSO anchor location; anda number of 5m deep CPTU profiles, aiming at improving the knowledge of seabed conditions for the pipelines and manifold foundations.

The soil conditions, consistent and uniform over the whole Girassol field, are composed of soft organic clay of high plasticity.
Expandable Technology: The first ten years
Authors: Metcalfe Paul
Published: October 2008

Expandable technology is capturing the imagination of the oil & gas industry because of its ability to significantly reduce well costs whilst improving well functionality and performance. This paper will describe the fundamentals of pipe expansion, the differing types of expandable tubes and the evolution of the Technology from the first laboratory trials, through the early field tests and into commerciality. Barriers to entry of new technologies are discussed, together with the importance of Operator involvement. Milestone product developments are described and are supported by field trial information. Both expandable drilling liners, expandable sand screens, expandable casing cladding systems and expandable liner hangers are discussed. The final section of this paper will look forward with a reasoned view on the potential state of the technology within the next 5 years.

Introduction-

The development of technology within the oil & gas business has simple drivers and is related almost directly to the maturity of the oil & gas business itself.

As the world's reserves portfolio ages, the effort required to find, develop and produce our reserves is increasing. This would result in increasing costs and without new technology, the costs of producing would make hydrocarbon products uneconomic. Cost reduction is therefore the major driving force behind technology development. Expandable technology is seen as a means of reducing the overall cost of a well and its support infrastructure. The application of the technology within the first ten years has been aimed mainly at those wellbore construction techniques that have remained unchanged for decades.

Telescoping casing designs have existed since the very first wells and reservoir completion practices have remained stagnant, dominated by gravel packing. The basic design of liner hangers, packers and through tubing straddles has not changed either; expandable technology will, and already has revolutionized techniques in these areas.

Whilst the "reforming" of pipe has been commonplace within in the industry for decades, notable activities including the swedging out of collapsed casing and the setting of thin walled casing patches, these do not classify as expandables under the term used today; The increase in circumference of a cylindrical pipe downhole, achieved through a wall thinning process and resulting in a cold working of the material through plastic deformation, was championed in the early 1990's by Shell International research staff. Shell's vision for the technology was also driven by the desire to reduce costs-by reducing the quantities of consumables used to construct the well. They reasoned that reducing the telescopic nature of a conventional casing design would allow a much smaller surface casing to be used and each subsequent casing could be reduced in diameter. Tangible savings are reduced drill cuttings, reduced mud volumes (& waste), with reduced steel, cement and chemical consumption.
Hang Tuah: Self-Installing, Relocatable Compression Platform
Authors: Tuturea D.P. , Jackson G.
Published: October 2008

The West Natuna Sea gas development called for the delivery of 325MMscfd of natural gas from Indonesia to Singapore via a 500km subsea pipeline. To deliver Pertamina - Conoco Indonesia Inc. Ltd.'s part of the contracted gas volumes required production and compression of associated gas from Belida and non-associated gas from new reservoirs over a wide area. As reserves become depleted and new fields are brought on stream, the compression facilities are to be relocatable.

This paper describes the evaluation process that led to the selection of a new-build self-installing steel gravity platform. This is believed to be the first major production platform to be designed from the outset for ease of re-location.

The development of the suction gravity base design, the jacking system employed and the offshore installation of the platform are described.

Background

The South Natuna Sea Block B Production Sharing Contract (PSC) is located in the West Natuna Sea area approximately 1000km North of Jakarta and 360km North East of Singapore. Block B exploration started in 1968, and while the initial focus was on finding oil, in the course of exploring for oil, several gas fields in the range of 70 to 300 BCF were discovered.

Efforts began in 1985 to commercialize this gas and, after extensive studies, it was concluded that the most attractive way to recover the value of these gas reserves was to adopt a phased development approach. The commerciality of this approach was made possible by Pertamina, Indonesia's national oil and gas company with its three West Natuna Sea production sharing contractors joining forces to market gas from Block A and Kakap Block together with Block B. Discussions began in earnest in early 1997 culminating in the April 1999 execution of a Gas Sales Agreement with Singapore.

The first step in meeting the gas sales commitments was the construction of the gas export trunkline from the West Natuna Sea to Jurong Island in Singapore, known as the West Natuna Transportation System (WNTS). The pipelaying for WNTS started in January 2000, and the system was successfully commissioned in January 2001.

For the Conoco operated Block B another important step was the design, construction and installation of a Movable Offshore Gas Production Unit (MOgPU), to provide flexibility in the development of scattered pockets of dry gas located over a 1600kmÂ2 area in water depths ranging from 70 to 100m.

What is a MOgPU?

The MOgPU acronym is simply an extension to the common industry designation "MOPU" meaning Movable Offshore Production Unit. The lower case "g" was added to recognize the specific application of the West Natuna MOPU as a gas processing unit, not to create a new class of production units. The Hang Tuah MOgPU provides all the benefits of a bottom-founded structure with the ability to be relocated to other areas of the Natuna Sea any time during its 25-year design life.
The Global Warming Issue: Current Status
Authors: Westbrook Gerald T.
Published: October 2008

President Bush has once again, and rightfully so, rejected the Kyoto Treaty. In contrast, the international community has indicated a strong desire for this type of diplomacy to continue. For example they voted 179/180 vote at Bonn for a modified but dramatically weakened accord. The results of this July 2001 Bonn meeting surely are hard to hold up as a victory. However the supporters of this treaty will do exactly that. The media support for those who are at least willing to do "something" has been and will continue to be very strong. President Bush is under major pressure to do "something", including pressure from some in the oil industry and some in the Senate.

The global warming debate is still very much alive, albeit pushed off center stage for the present. The other industrial nations seem willing to support, indefinitely, diplomacy dominated by process over substance. The ultimate resolution of this fight is of major import to the energy industries. Some of the forces involved in this debate also advocate zero drilling in the ANWR, zero drilling off or even near Florida and indeed the ultimate phase out of oil.

This paper is the fourth report by this author to the OTC on this issue. See OTC #8689, OTC #10773 and OTC #12115. This latest report will provide an update and overview on the status of the debate.

Introduction

As this report is being prepared, the war against terrorists is still underway, albeit with substantial success already achieved. There are signs today that the Administration is starting to address some domestic issues, such as the economy and education. It was their intention to address global warming late in 2001, and to come up with their alternative plan to the Kyoto Treaty. That did not happen, and it is unclear where this fits on their priority list. I suspect it will remain relatively low for awhile, but it will not go away. The proponents of the Kyoto Treaty have too much time and effort invested for them to walk away from this issue. If one assumes that global terrorism can be put into a manageable box, then the warming issue will reemerge, as cantankerous as ever.

It has been two years since I last reported to the OTC on this subject. In the prior papers most of the inputs covered the status of the global warming sciences. In this paper we will look at the science again, or more precisely, reports about this science, then look at the status of the global warming treaty. Finally we will look at U S. policy efforts in lieu of the Kyoto Protocol.

Situation Review

Status of the Global Warming Sciences.

We asked at the start of the 2000 OTC paper if the science is done? As before we believe that nothing could be further from the truth. Even having met and passed into the Third Millennium the science on this issue is still far from done.
Canada's Wave Climate and Field Measurement Program
Authors: Baird W.F. , Wu H.J. , Holland G.L. , Wilson J.R.
Published: October 2008

The Department of Public Works of Canada initiated in 1968 a joint project with the Department of Energy, Mines and Resources to obtain, mainly by field measurement, information on the wind generated wave climate on the major coastlines and lakes of Canada.

The first major year of field measurement was begun in 1970 using Datawell "Waverider" accelerometer buoys and pressure sensors developed by the National Research Council of Canada.

The recording units for both sensors have been operated for twenty minutes every three hours; the accelerometer buoys were moored inapproximately 25 fathoms and the pressure sensors located in approximately 30 feet of water. During 1970 accelerometer buoys have been installed and operated on the Pacific coast of Vancouver Island and on the Atlantic coast of Nova Scotia; the pressure sensors were installed and operated on the south coast of Newfoundland. The greatest success was obtained from the accelerometer buoys, however, difficulties were encountered with the mooring system.

It is intended that this wave climate study will continue for the next three years, and possibly longer, recording data off the major coastlines and lakes of Canada.

Data obtained during the first year of measurement are presented in summarized form in this paper. It is intended that all the data recorded during the project will be presented in this form.

INTRODUCTION

Canada has a coastline of considerable length and a correspondingly large continental shelf area. Many of its national resources are closely related to the coastal and marine environment. A requirement exists within Canada, and similarly within other maritime countries, for environmental data from the surrounding oceans and internal seas. Wave information forms an integral part of the required data and possibly covers the widest spectrum of requirements. Synoptic information for fishing fleets and ship routing, design wave predictions for coastal protection and harbours, statistical data for oil drilling operations and wave climate forecasts for ferry services form only part of the overall need. It is difficult to imagine any oceanic undertaking that does not require wave data in some aspect of its program.

Realizing the need for an observation and analysis program to support the growing expenditure on marine projects the Canadian government approved a proposal initiated by the Department of Public Works undertaking the measurement of the wave climate of Canadian coastal and inshore waters. The following report is an account of the first full year of this program together with the presentation of resultsfrom one of the East Coast locations.

HISTORY

In 1968 the Department of Public Works initiated a proposal to conduct a wave climate survey of Canadian coastal and inshore waters.
FPSO Offloading Concepts, their Nautical Feasibility and Safety Assessment
Authors: van Doorn J.T.M. , ten Hove D.
Published: October 2008

Introduction

For the development of offshore deepwater oil or gas re-sources more often F(P)SOs, Floating (Production) Storage Offloading units are applied. For the export of oil (or gas) from the FPSO tankers are used. In the design of a FPSO various options are available for offloading: tandem from a turret moored or spread moored FPSO, tandem from a Single-Point-mooring (SPM) or side by side from a turret moored FPSO. The technical design, but also the nautical operations are highly affected by the choice of the offloading system. Aspects that are affected are:Weather downtime, which effects the overall economic performance of the FPSO;Safety of day-to-day operations, which requires clear procedures, trained personnel and the right type of equipment;Controllability and response in case of emergencies;The overall safety of the operations, the probability of a collision and the related collision energy.

All these aspects play a role from day one of the design of an offloading facility until the facility becomes operational. In this paper we will show how various tools, together with experience and common sense can help to take decisions and to prepare people for the offloading job ahead.

The paper can be divided in the following main sections:Nautical considerations in the design of an offloading facilityFast-time manoeuvring simulations: operational limits and procedures;QRA, Quantitative Risk Assessment;Real time simulations and training;Conclusions.

Nautical considerations in the development of an offloading facility

Nautical aspects play a role throughout the development of the F(P)SO. Three phases can be distinguished in this development:Phase 1: Pre-design: selection of concept, selection of location;Phase 2: Design;Phase 3: Implementation and operation.

The tools/methods available for the evaluation of the nautical aspects are:Static computations;Fast-time simulations of normal operations;Fast-time simulations of emergency situations;Quantitative Risk Assessment;Real time simulations.

The applicability of the various tools in the various development phases is shown in Figure 1, below

Figure 1 Tool or methodology to be applied during various development phases (available in full paper)

In this first phase: (Pre-design: selection of concept, se-lection of location), the design will focus on the selection of the offloading facility and the selection of the site. Aspects that play a role are, amongst many others, the environmental conditions, type and size of the offloading tanker and the assistance of tugs.

Reliable statistics regarding the local climate: e.g.: wind, current and waves are essential to make a reliable evaluation of the various options. In this first phase the methodology for the evaluation of the various concepts is kept simple to be able to make a fast comparison. Experience in combination with static computations or fast-time simulations are the most likely tools to be used.
Getting Smart With Competence
Authors: Bexon Mark , McAteer Peter
Published: October 2008

Deploying competent personnel is arguably the most significant factor in managing risk and improving efficiency in safety critical operations. It is generally recognized that the combination of an ageing workforce [the average age of a UK North Sea worker is 47] and a widespread and progressive decline in new entrants into engineering is creating a serious skills shortage in the Upstream Oil & Gas industry.

There is an industry-wide consensus that to avoid a collision between these critical influences we must accelerate personnel development and make best use of the skills and expertise in place, One of the major initiatives being taken is to drive better skills management through applying objective quantification to measuring competency and in deploying IT to understand where skills are required and where they reside in an organization. This paper outlines the basics of such a system and the "Knowledge Management" benefits flowing directly from effective IT functionality when applied to Competency Assurance

As an industry we have been producing competent people for years. However, now we need to do it faster, better, in a dynamic environment and to be able to demonstrate that we have done it, should we be called upon to do so. This new approach has been developed originally with BP, then Mobil and more recently Shell and Kerr McGee. All these Operators, in this period, assisted in the development of the system and have contributed to its success

Background

The oil business has worked with different measures of competence for some years now. In the early days recruitment ranged from graduate intake to whoever could be hired in the bar for an operation that was to commence the following day.

Piper Alpha was a watershed that clearly demonstrated that how we managed our business was just not good enough and we have progressed to a status where all companies believe ‘zero tolerance of loss’ is the only acceptable standard to operate by. Society's attitude to incidents and injury has shifted to one of intolerance, increasing the pressures on companies to have effective safety management systems incorporating safe places of work, a competent work force and a commitment to sustainable development. The progressive encroachment of legislation into our working practices, some aimed directly at bringing to account the most senior officers of a company for HS&E failures is evidence of the importance that Society places on how we execute these responsibilities

Regulations were introduced that required oil related companies to assure themselves that their work force was competent in safety critical areas. The UK legislative premise of self-regulation post Piper Alpha has become the model adopted by a number of International statutory bodies.

Further pressures have been put onto the oil industry by the inability to attract young people into engineering " particularly oil related engineering " perceived as a ‘twilight’ industry..
Deep Draft Floater Motions - Verification Study
Authors: Johannessen Thomas Berge , Wanvik Leiv
Published: October 2008

The paper presents the main findings from an internal verification study on motions of the Aker Kvaerner Deep draft Floater (DDF). The study employed traditional linear analysis techniques as well as coupled and uncoupled time domain analyses. The coupled analysis is carried out utilizing state of the art software belonging to the Norwegian Marine Technology Research Institute (Marintek) program portfolio and developed further in the DEEPER Joint Industry Program organized by Marintek and Det Norske Veritas (DnV) (ref /1/). The analysis case is based on the functional requirements of a DDF with 56 000 Mt displacement and up to 30 rigid risers. The DDF has been analyzed at 1400 m water depth both in a West Africa and a Gulf of Mexico natural environment.

By investigating the effect of including keel plates at large depths below the SWL, the heave response of the DDF can be controlled without significantly increasing the heave excitation on the structure. The 100-year return heave response has been found to be less than 1 m and 2 m for, respectively, the West Africa and the Gulf of Mexico Environment.

By comparing coupled and uncoupled analyses of the DDF motions it is concluded that the effect of coupling is slight at 1400 m water depth. With 30 rigid risers present, the fully coupled model will predict approximately 10 % smaller motions than the uncoupled time domain analysis model.

Introduction

Aker Kvaerner have taken part in the DEEPER JIP development project. As a part of the breaking-in exercise of new deep water time domain analysis software and in order to thoroughly investigate the scope for optimization of the DDF motion behavior, Aker Kvaerner decided to run an advanced verification study on motions of the Aker Kvaerner DDF. The scope of the analysis was as follows:Investigate and optimize first order heave motion of the Deep Draft Floater (DDF) using first order radiationdiffraction analysis. This is carried out employing the WADAM program which is based on WAMIT5 /2/.Investigate the motion of the DDF using the time domain analysis program SIMO developed by Marintek /3/.Investigate the motion of the DDF using SIMO coupled with RIFLEX as described in /1/Verify and optimize mooring line, riser and tensioner design.develop a DDF sizing tool which calculates stability and gives an accurate estimate of first order heave response. The three first points above are addressed in the present paper.

The Aker Kvaerner Deep Draft Floater

General.

The Aker Kvaerner DDF is a general-purpose marine facility for deep water environments. The design is focused on minimal vertical (heave) motions in order to facilitate rigid marine risers with dry trees. This type of design is very little affected by a change in water depth making the DDF ideal for use in deep waters. The DDF as shown in figure 1 can functionally be described as a multi-leg Spar or Truss Spar.