bluuebunny/crossref_metadata_2025_split huggingface dataset:
Gravity Modeling of the Song Hong Basin, Offshore Vietnam
Authors: Nguyen V.G. , Rabinowitz P.D. 
Published: October 2008

Abstract
3-D gravity inversion and rift stretching models are used in the Song Hong basin to determine the general configuration of the upper mantle and the mechanism for its formation in the region. The basin approximately 200 km wide by 600 km in length, contains up to 14 km of sediments. The Bouguer gravity field over the basin is relatively flat varying from 0 to -35 mgal, suggesting high density material at the base of the crust. 3-D inversion was implemented converting modified Bouguer gravity anomalies and using Cordell-Henderson gravity inversion method. Several rift stretching models were calculated using basement depths based on seismic studies and drill holes. The results of gravity modeling suggest that the Song Hong basin is a passive rift in which the failure of lithosphere is due to tension stress which introduces asthenospheric materials to the base of the crust. The tension responsible for the rifting is most probably linked to the collision between the India and Euroasia lithospheric plate.

Introduction
The Song Hong basin is located on the continental shelf of Vietnam and covers most of the Gulf of Tonkin (Fig. 1). The basin was formed at the northern edge of the Indochina block and is cut through by the strike slip Red River fault system.
The mechanism and tectonic evolution of the basin are linked to the motion of the Indochina block along the Red River fault. The Red River fault is a Mesozoic fault reactivated by the India-Eurasia collision during the Tertiary1. The amount of displacement and type of motion of the Indochina block during the Tertiary still remains in debate. Models in which the Indochina block moved southwestward from Eurasia along the Red River fault in response to the northern motion of India in the Eocene have been proposed2–4. The displacement was first left lateral in the Tertiary and then reversed to right lateral as India further collided into Eurasia and caused the south China block to move during the quaternary. This model requires the Indochina block to act as a rigid block and displace dextrally as much as 500–700 km along the Red River fault as it moved away from the Eurasia (Fig. 2). In contrast, other models5 propose a lithospheric thickening of Eurasia to accommodate for the India-Eurasia collision. Indochina is thought to undergo internal rotation as the result of the India collision5–7. The amount of dextral displacement of the Indochina block during Tertiary inferred from these studies was small. Deway5 estimated the maximum eastward extrusion of convergence zone which is linked to Indochina block of about 250 km.
The rhombohedral shape elongated along the Song Hong basin axis suggests that the basin had a strike slip origin associated with the Red River fault displacement. However, seismic data8–9 reveals that the strike slip motion along the basin is small and the major opening direction of the basin is NE-SW prior to 30 m.y.
Design and Fabrication of the URSA TLP Deck Modules and TLP Hull Upper Column Frame
Authors: Zimmer R.A. , Figgers R.F. , Geesling J.F. , Kim H. , Yeung D.H. , Banatwala Z. , Sidwell G.A. , Stout J.A. , Harris B.W. , van Vugt M.A. 
Published: October 2008

Abstract
This paper discusses the design and fabrication of the URSATLP deck modules and upper column frame. The URSA TLP is installed at Mississippi Canyon 809 in over 3800 feet of water. The high rate URSA wells are produced through large diameter tubing strings inside dual cased risers. The URSA topside package includes a full drilling facility and production facilities that can process 150,000 barrels of oil and 400 million scf of gas per day. Also, as the URSA TLP has potential to act as a hub for the surrounding fields, it can carry an additional flexibility payload of about 3000 short tons.

Introduction
The large size and weight of the URSA facilities, production risers and drilling riser presented major challenges for the URSA deck structural design team as well as for the deck and hull fabrication teams. Further, these challenges had to be met on a fast track project schedule.
The above deepwater challenges were met by using structurally independent deck modules in conjunction with an upper column frame featuring knee braces built into the TLP hull for support. An integrated project team approach in conjunction with a "design while you fabricate" philosophy was successfully used to complete the design, fabrication and erection of the deck modules and upper column frame within the fast track project schedule. The installation of the large modules onto the hull was achieved with a semi submersible construction vessel.

Structural Design

Deck Configuration and Loads
The URSA TLP Deck Modules, Upper Column Frame (UCF) and Hull are shown in Figure 1. There are 4 structurally independent perimeter modules, which span from column top to column top. They are the process module composed of the process south and process north sub modules, the power module, the quarters module and the drilling module. These modules support the very large URSA production facilities. The process module is approximately 300 feet long, 125 feet wide and 50 feet high. It has 4 deck levels, an upper deck, intermediate deck, mezzanine deck and a lower deck. These large modules were also designed for future production facility expansion and subsea tie-ins in addition to the initial URSA facilities. The wellbay module, located at the center of the platform, has 24 slots. It was designed to provide direct vertical access to as many as 20 wells via top tensioned risers. The upper column frame (UCF) supports the wellbay and ties the four 85 foot diameter upper hull columns together. The URSA deck system carries a total of about 42,000 short tons of payload including its own steel weight. This is almost twice that of the Mars and Ram Powell TLPs and about 5 times that of the Jolliet TLWP.
Design and Optimisation of Taut-Leg Mooring Systems
Authors: Johnsen John Magne , Øritsland Ola 
Published: October 2008

Abstract
A three year research programme focusing on the challenges related to Taut-Leg Mooring Systems (TMSs) has recently been completed. The programme has been funded jointly by the Norwegian Research Council, oil companies and contractors.
This paper describes the work performed on system design utilising synthetic fibre ropes and vertical load capacity anchors. The main objectives have been to perform designs, address technical issues important for the design, and carry out model tests for verification purposes. The cost effectiveness compared to conventional catenary moored systems (CMSs) has also been studied.
As basis for this work a semisubmersible drilling rig, a FPSO and a semisubmersubmersible production vessel were used, and both Vøring (North Sea) and West of Africa environmental conditions were considered. The base case water depth was 1 500 m, but TMS designs down to 350 m water depth has also been included. Polyester has been used as the base case fibre, however, some evaluations has also been made for aramid.
A discussion on parameters important for TMS optimisation is given in the paper. It was found that the safety factor sensitivity to uncertainties in rope stiffness properties is not too severe, especially in the case of semisubmersibles or in calm waters. Compressive fatigue is often flagged as a potential problem for TMSs, but it is shown that the number of minimum tension cycles can be controlled by a careful tuning of pretension and bottom chain segments (in case of polyester ropes). The model tests demonstrated the favourable offsets provided by a TMS. Apart from offset (including slowly varying motions), there were no large differences in motions characteristics between a TMS and a CMS. The comparison to computations did also reveal the difficulty in predicting wave induced slowly varying motions, both for TMSs and CMSs. Based on mooring line cost alone, it was found that a TMS can compete with a CMS down to almost 350 m of water depth. The differences in cost increases in favour of the TMSs with increased water depths when including system costs.

Introduction
As oil exploration and production is moving towards greater water depths there is need for cost effective station keeping systems. The principal function is to restrain the lateral movements of a floating platform, and conventional CMSs have a relatively low lateral stiffness. A TMS may provide much smaller offsets, which implies shorter riser lengths or it may even facilitate for other riser solutions. A tight watch circle will also reduce operational costs and increase drilling availability. At large water depths the use of CMSs causes very long and heavy lines, and the fabrication and installation costs become major cost factors. The lines will also require a large footprint and may become a potential hazard for the subsea equipment on the sea bed.
Reliability of Mooring Systems: Application to Polyester Moorings
Authors: Snell Richard , Ahilan R.V. , Versavel Thomas 
Published: October 2008

Abstract
The trend to deep water oilfields has accelerated the development of mooring systems. Future moorings requirements represent a considerable step out on current practice, Polyester moorings offer considerable economic and operational advantages.
The authors have previously used experience gained orr an FPS in combination with reliability analyses tn predict the failure probability of two harsh enviromnent FPSO Riser/Mooring systems.
Recent work has built on this experience to predict the failure probability of polyester mooring systems and compare it with steel wire mooring performance.
The paper outlines the previous work which provides the common basis for comparative reliability predictions of polyester moorings. The new polyester mooring reliability predictions are presented which make a significant contribution to demonstrating the acceptability of polyester moorings for production systems.

Introduction
The application of polyester to the moorings of production systems brings considerable potential economic advantages. Firstly the lower in water weight compared to steel wire rope systems significantly reduces the buoyancy in the production system required to support the mass of the mooring system with associated wave load reductions. For a 2000m water depth FPSO mooring in the GoM the still water mooring weightload is of the order of 220 tonne compared to a polyester line pre-tension of 130 tonne.
Secondly the reduced offset afforded by taut polyster mooring system can provide considerable benefits in the design of the risers. For very deep water risers steel pipe rather than flexibles is required. For Spars and Semi's the riser bending forces and fatigue are a direct function of offset.
Thirdly, the use of taut polyester lines reduces the mooring system footprint thus providing greater flexibility in subsea achitecture. For instance, the ability to route the flowlines so that these may be brought up to the FFSO in clusters can be economically achieved when the footprint is small.
Steel wire rope and chain mooring systems have become accepted practice largely as a result of decades of experience and development of the materials for shipping and land based purposes and the subsequent development of oil industry specific materials and mooring design standards with appropriate design margins. (Refs. l&2). Polyester does not have the option of decades of development including the trial and error process inherent in early applications.
The development of polyesler as a mooring material was driven primarily by scale aud fill sealc laboratory investigations of competing materials in the UK. The laboratory work, whilst providing a sound understanding of extreme load fatigue capability and the effect of slack or local compression in a rope, was not able to fully characterise long term nonlinear stiffness.
Station Keeping in Deep and Ultradeep Waters
Authors: Del Vecchio C.J.M. , Costa L.C.S. 
Published: October 2008

Abstract
This paper describes a development program being conducted by Petrobras to develop reliable and through life cost effective moorings for depths to 3,000 m. Four alternative solutions are considered: spread catenary, taut leg, taut with submerged buoys and differentiated compliance (DICAS) mooring systems. For each system, four main aspects are being investigated: materials, design procedure and criteria, installation and maintenance. This program has started in 1996. Results already obtained show that: its is economically feasible to moor exploration and exploitation floaters in water depths to 3,000 m. The paper also discusses the most cost effective options for these moorings and key parameters to select, design, install and operate them.

Introduction
Since 1986 Petrobras has foreseen that fiber ropes would play a key role in extending the depth capability of drilling and production vessels. Initial studies concentrated in substitutes for steel wire rope in catenary systems with grounding chain and drag embedment anchors. Kevlar aramid ropes were qualified for this application by developing handling procedures and conducting two sea trials1.
However, the introduction of fiber ropes in spread moorings called for a systems approach to design and materials selection. A pilot study showed that, to meet standard requirements for maximum offset for flexible and/or drilling riser, polyester (PET) fiber ropes would be the most cost-effective option2.
Detailed studies characterized the relevant properties of these ropes, appraised their use in catenary and taut leg moored semisubmersibles in water depths to 1,500 m, and developed basic design procedures and criteria3,4.
From 1992 to 1996 basic installation procedures were developed and tested. Also medium to long term trials in catenary system were set up. Initial Results from field samples were promising.
By this time Petrobras was faced with the challenge of developing Marlim Field, using several floaters. Congested seafloor layout and provision for workover demanded short radius mooring systems for these floaters. An appraisal of the state of the art and internal experience with PET fiber ropes led to the adoption of taut leg systems based on these ropes for three semi-submersibles for this field5.
Also the challenge of installing FPSO-II in 1,420 m of water in Marlim South Field, with the deepest anchor set in more than 1,600 m, led to the choice of a catenary system with long PET fiber rope inserts for the mooring lines.

Ultradeep Water R&D Program
With the ongoing exploration and exploitation projects in mind and foreseeing the need to moor drilling, production, storage and offloading facilities in water depths to 3,000 m, a research and development program was put together by Petrobras.
DeepLook: Toward the Common Goal of Reservoir Characterization Through Collaboration
Authors: Chawathé Adwait 
Published: October 2008

Abstract
In its illustrious 150 years history, the oil industry has conjured up ingenious methods to predict fluid flow behavior around the extended vicinity of the wellbores. In the past decade or so, this effort got a real shot-in-the-arm with the advent of high-speed computers. Despite this monumental development, petroleum engineers and earth scientists still struggle to merge various data sources and technologies to achieve the paramount objective: Reservoir Characterization. The DeepLook collaboration, an idea originated by BP, was contrived to address the same objective; but uniquely, through inter-company partnership.
The DeepLook Fluid Imaging Collaboration-formally initiated in 1997-is currently supported by seven oil and six service companies. The collaboration seeks to define and investigate technologies that could provide a fundamental improvement in the oil industry's ability to measure reservoir fluid and rock properties, and monitor fluid movement, at distances of 10 to 200 meters from existing wells. The goal is to achieve significant reliability in spatial and temporal fluid imaging, thus enabling substantial increases in the recovery efficiency. This challenge is being addressed through identification and sponsorship of promising breakthrough technologies which are being developed for applications outside the oil industry, by what have been termed "farmarket" high-technology organizations. This paper is a progress report of the DeepLook collaboration achievements.
The collaboration was launched with an "Oil Industry Outreach" workshop to inform interested potential far-market technology providers of our current practices in fluid imaging and reservoir management. Three DeepLook technical teams-Detection, Monitoring, and Prediction-were specifically established towards the objective of disseminating the information as well as guiding the needs and challenges of reservoir management and fluid imaging.
The "far-market" technology organizations normally operate outside the realm of the oil and gas industry. At present, the suppliers comprise four United States government Department of Energy laboratories and NASA's Jet Propulsion Laboratory. This paper will briefly discuss the retro-fitting of the following state-of-the-art technologies developed by these labs to the oil industry:Using Artificial Neural Networks and Genetic Algorithms for Optimal Well Design.Adaptive Forward-Inverse Modeling of Reservoir Fluids Away from WellboresSwept Frequency Acoustic Interferometry for Fluid Identification Each of the projects has an agreed-to work-plan, with specified milestones/deliverables.
A multi-company collaboration as complex as DeepLook is expected to encounter growing pains. Along with the technological advances, the paper also addresses some of the challenges encountered and the pro-active measures taken to overcome the management issues.
A New Approach to Derrick Barge Design
Authors: Goren Yoram 
Published: October 2008

Abstract
In most cases derrick barges are forced to suspend operations when wave heights exceed five feet and, in many cases, as low as three feet. This severe limitation called for a new approach to derrick barge design.
Close analysis of the life span of a typical heavy duty barge shows that during about 85 percent of her life, the barge negotiates lighter loads than her maximum capacity. Before and after setting a package weighing as much as 500 to 800 tons, the barge will spend time driving piles, assisting construction and hoisting small weights which, in most cases, will not exceed 100 tons. The objective of this design was to build a column stabilized derrick barge capable of handling up to 800 tons on the crane or 2, 000 tons on the shear leg when hull borne and up to 250 tons when column stabilized in waves exceeding 10 feet. The further objective of this design was to build a vessel which is competitive in cost with existing vessels of similar capacity.
The above objectives were realized by an extensive development program which was conducted in two phases. The first phase was the preliminary design phase in which system operational considerations, such as self-sustaining characteristics, crane load, accommodations, machinery, towing speed, etc., were pitched against engineering considerations, such as CG, weight distribution, natural periods, etc. The result of the preliminary evaluation was a twin hull, variable draft, column stabilized derrick barge having a beam of 106 feet, to enable it to pass through the Panama Canal, and a length of 400 feet.
The next phase in the development was a series of three tank tests. A preliminary one, conducted in General Dynamics Electric Boat Division, and two additional ones conducted at The Netherlands Ship Model Basin in Wageningen, The Netherlands. The purpose of these tests was to analyze the vessel's motions, to evaluate mooring forces, to determine various dimensions and to assess the bending moments imposed on the vessel. Most important, the above tests made it possible to evaluate the operational feasibility of the proposed design.
In conclusion, it may be stated that this paper demonstrates a way to approach and solve a complex engineering and economic problem, one of many encountered daily in the new and expanding field of offshore technology

Introduction
Recent developments in offshore construction have brought about an increase in size and capacity of derrick barges in order to satisfy the demands of the industry and make it possible
ABS Guide for Synthetic Ropes in Offshore Mooring Applications
Authors: Lee Ming-Yao , Flory John , Yam Rod 
Published: October 2008

Abstract
The ABS Guide for Synthetic Ropes in Offshore Mooring Applications [Ref. 1] is developed to assist the industry with standardized criteria covering all aspects of the use of these advanced materials for offshore moorings. Synthetic ropes have many advantages in deepwater moorings, but their unique properties must be accounted for in the mooring system design process. For example, synthetic rope moorings rely primarily on rope elasticity for restoration forces, but the elasticity is nonlinear and changes with time.
Emphasis is given to identifying the primary differences between the conventional steel components and their synthetic counterparts with regard to the influence of rope properties on the mooring system performance. Sufficient details will be provided to determine these properties through rope testing and to account for them in the mooring design process.
This paper describes the ABS classification/certification approach on synthetic ropes, which covers mooring design and analysis; rope design, testing and manufacturing; rope handling and installation; and rope inspection and maintenance. To provide an industry-wide acceptable standard, ABS formed an Ad Hoc committee consisting of operators, designers, rope manufacturers, installation contractors and governmental agencies to provide advisory comments to the Bureau on the development and future enhancement of the Guide.

Introduction
With the advent of deeper water exploration and production, it has become necessary to seek alternative materials for economical and/or suitable mooring solutions. This is reflected in the offshore industry's initiative to adapt synthetic fiber materials such as polyester, aramids and HMPEs for these purposes.
Synthetic ropes may be used as mooring line segments in steel catenary systems, or in taut leg mooring systems. In the taut leg system, the elasticity of the synthetic line provides the restoring force traditionally supplied by the geometry of the catenary system. Other differences from that of the steel wire/ chain mooring systems include the non-linear stiffness, minimum tension requirements, location of synthetic rope segment to be away from fairlead and seafloor, creep phenomenon, and handling of the larger sized rope.
Where synthetic ropes are used, it is possible to reduce the mooring footprint, and hence reduce overall spread of the subsea installation. Other advantages include the reduction of mooring line weight, better corrosion resistance, and in some cases lower vessel offset and simpler installation techniques.
A systematic investigation on the use of synthetic fiber materials for deepwater moorings only began in the early 1990s [Ref. 18]. The publication of the "ABS Guide for Synthetic Ropes in Offshore Mooring Applications" marks an important step the industry is taking to advance this new technology, and reflects the need for a consolidated written design guidance.