bluuebunny/crossref_metadata_2025_split huggingface dataset:
Wet Deck Slamming Analysis of Twin-Hulled Offshore Ship in Irregular Sea Waves
Authors: Lubeena R. , Gupta Vinay Kumar , Agrawal Madhusuden 
Published: June 2014

In ship hull design, it is important to predict the seakeeping parameters like ship motions, vertical accelerations, wave impact loads, deck wetness, etc. when the ship is subjected to waves. According to the ABS Guide for Building and Classing High Speed Naval Craft (HSNC 2007) slamming impact load is one of the most critical factors for the scantling design of hull structures[7]. Accurate prediction of wave impact loads requires solution of three problems. First one is the prediction of wave kinematics, second one is the prediction of the pressure and viscous forces and the third one is the prediction of ship motion during the wave impact.This paper focuses on the wet deck slamming analysis of twin-hulled offshore ship in irregular sea waves and proposes a Computational Fluid Dynamics (CFD) solution using Volume of Fluid (VOF) method and Six Degrees of Freedom Model (6DOF). Irregular waves were modeled using JONSWAP wave spectrum. The wave profile obtained from the numerical simulation was validated with analytical results. The wave impact load and the hull motions depend on many factors, such as sea state, ship speed, draft, wave heading angle, hull structure, ship loading condition etc. In this paper, we have analyzed the wet deck slamming for a survival condition with sea state of significant wave height of 9m with two different ship loadings and two different ship speeds. CFD analyses were also carried out for calm sea conditions with different ship loadings. The heave and pitch motion of the ship in wave conditions are compared with calm sea conditions. The ship motions, vertical accelerations, pitch velocities and the wet deck slamming pressures are compared for the two ship loadings and two ship speeds. This paper describes these results in detail.
Offshore Tandem Loading of LNG – from Idea to System Approval
Authors: Eide Joergen , Haakonsen Rune , Oya Tor Vidar , Frohne Christian 
Published: June 2014

The paper describes the background and design approach used to develop and qualify a LNG transfer system to be used for tandem loading between a LNG producer (FLNG) and an LNG carrier (LNGC), specifically in harsh environments. Although tandem loading of crude oil is being performed worldwide every day, such operations are always challenging in harsh environment. Transfer of LNG between two large vessels is even more challenging, as the standard rubber hoses used in Crude Oil transfer operations no longer can be used due to the product's low temperature. The core issues in LNG tandem loading are;The suitability and qualification of the hose/flexible pipeThe marine operations and vessel motions in relation to Dynamic Positioning systemsThe mechanical design of the loading system
The development of the Offshore Cryogenic Transfer system (OCT) has been based on proven technology wherever possible, not only for components but also for procedures. The OCT System can be an enabler for the development of large offshore gas fields or stranded gas using FLNGs in combination with LNGC's, specifically for harsh environment applications. Several LNG transfer system solutions have been put forward over the past decades, either based on specific transfer ideas or individual product proposals. Of these, the OCT System is the only Tandem LNG Transfer System that has been awarded a system approval by DnV according to RP A 203 / EN 1474–3, as far as is known. The system approval depends on the approval of the main sub-systems according to EN 1474–2; the pull-in and connection, the connectors and the transfer hose/pipe itself.
There are significant challenges involved in offshore LNG transfer between floating units. The following five critical technology areas all need to be successfully addressed and solved in the development and qualification of an LNG loading system:Safe operation of two large vessels during the final approach, connect, loading and disconnection phasesThe performance / operating life / safety features of the flexible cryogenic pipes for LNG transferThe design of the flexible pipe manipulating arm / A-frame storage system on the FLNGDesign of the pull-in and connect system in the bow of the LNG carrierQualification of the sub-systems and overall solutions according to EN 1474–2 and EN 1474–3
An LNG transfer system is inherently more complex than crude oil loading due to the requirement of a return gas path. That means that minimum 2, possibly 3 hoses/pipes needs to be connected to the bow of the LNGC instead of the single rubber hose as used in crude oil transfer systems. These subjects are elaborated in more detail in the following sections.
Developing a mechanical earth model using tectonic deformation coefficients in Ceuta VLG-3676 field, Maracaibo basin, Venezuela
Authors: Vásquez Vladimir , Lobo Carlos , Bois Axel-Pierre , Boutin Hugo 
Published: June 2014

Abstract
Reservoir Eocene C/VLG-3676 of Ceuta field, one of the major reservoirs in Maracaibo lake basin, is characterized by operational challenges that prevent its optimal production. Drilling is challenging and requires large mud-weights to reach target. In order to optimize drilling and completion operations, a geomechanical study was launched to develop a Mechanical Earth Model (MEM) and use it to improve well trajectory, mud-weight programs, and perforation strategies. The methodology followed when developing this MEM was:data audit and well selection;tectonics and structural-setting analysis;drilling-event analysis;mechanical-stratigraphy definition;rock-property evaluation;pore-pressure estimation;in-situ stress determination;wellbore-stability evaluation;mud-weight window determination; and
optimal well trajectory computation. The three most interesting features of this paper are:the analysis of more than 200 tests performed in laboratory on Eocene "C" cores that shows a very high degree of damage of the cored material;a new in-situ stress field determination method based on tectonic deformation theory; anda stress regime that changes from normal in the Miocene at shallow depths (200–5000'), to strike-slip and reverse in the Eocene at depths greater than 10,000'. This last result is of great importance for producing reservoirs in this area, as it not only impacts the evaluation of optimum mud-weight windows, but also well trajectories and perforation strategies.
Squall Wind Elevation/Gust Factors and Squall Coherence
Authors: Santala Markku J. , Calverley Mark , Taws Sarah , Grant Hazel , Watson Andrew , Jeans Gus 
Published: June 2014

AbstractA squall is a strong transient wind event generated by a convective storm. Though squalls are an operational concern over a wide range of latitudes, they are typically only design events in tropical areas. At this time, there are no widely accepted elevation and gust factors for squalls that are appropriate for engineering purposes. No specific guidance is given on squall gusts in the present API or ISO standards. The nature of wind squall events is fundamentally different than that of high latitude non-cyclonic storms and tropical cyclones which are presently the only types of wind events specifically addressed by API and ISO standards. Such factors are needed for squall events so that measurements made in different ways may be converted into homogeneous databases at specified elevations and gust intervals such that they can be analyzed in an unbiased way. Such factors are also needed to convert squall criteria values at a specified elevation or gust interval to a relevant elevation and interval required for the engineering of a specific structure or appurtenance.The West Africa Gust (WAG) joint industry project JIP was formed to better understand the nature of wind squall extremes offshore West Africa. The WAG JIP has concluded its third and final planned phase. The first phase of WAG focused on developing regional return period extreme value estimates of squall winds. The second and third phases of WAG focused on understanding the temporal and spatial nature of squall gusts in the context of the requirements needed for offshore engineering. Results were based on an offshore multi-anemometer array set up by the third phase of the JIP (WAG3) offshore West Africa.In this paper, expressions for wind gust elevation profile and gust factors are presented for squall winds over water. Coherence of longitudinal variations in squall winds is compared to the expressions for non-squall winds presently in API and ISO standards. The results presented herein will lead to an improved treatment of squall events for offshore engineering applications.
Remote Hydrocarbon Sampling Skid
Authors: Fowkes Mick , Bryson Kenneth , Ferguson Hugh 
Published: June 2014

Abstract
As the need to exploit offshore oil and gas deposits in increasingly challenging environments increases, the economic development and safe operation of technologies has become more critical.
The requirement to sample and establish the characteristics of produced well fluids has been long established in order to provide:Fluid composition and flow data for each wellReservoir management philosophyFiscal allocation
Traditional methods for sampling and testing of wells employed the use of a dedicated subsea test header, pipeline, or riser connected to test separators and individual single phase flow meters located on a surface production facility. But as production has moved to deeper water, Multi-Phase Flow Meters (MPFM) have been introduced to monitor or meter individual well production, prior to a production manifold combining the production from several wells for onwards transport in a single riser or flowline. Since reservoir and well fluid characteristics alter over their life cycle, it is essential that MPFM be recalibrated to account for this to ensure their continued accuracy.
Subsea 7 has developed and operated an ROV deployed Remote Hydrocarbon Sampling Skid capable of taking separate samples from up to eight individual wells in a single dive. During operation and recovery the temperature and pressure of the samples is maintained to prevent the sample coming out of phase and prevent hydrates forming in the sample or skid pipework. On recovery the sample bottles are removed from the skid and transported ashore for analysis to allow calibration of MPFMs and for fiscal allocations to be determined.
High Pressure Flexibles Pipes – Knowledge and Qualifications at 15 kpsi, 17.5kpsi and 20 kpsi Design Pressure
Authors: Deheeger Antoine , Bernard Gary , Secher Philippe , Estrier Pascal , Félix-Henry Antoine 
Published: June 2014

Abstract
Recently and particularly in the Gulf of Mexico, High Pressure reservoirs discoveries in ultra-deep water and deep formations were made. While the drilling rigs and well intervention vessels were traditionally fitted with 15 kpsi equipments, a growing number of rigs are now being upgraded to operate beyond 15 kpsi.
For more than 30 years now, Technip has been providing under Coflexip® trademark 15 kpsi rated flexible pipes qualified to API 16C and API 7K and is now moving toward 20 kpsi ratings.
At the same time, progress is continuously made in flexible riser technologies to enable service of production, water injection & gas injection in ultra deep water with maximum pressures up to 20 kpsi.
In this paper, Technip track record for 15 kpsi jumpers and production risers will be shown and the challenges to reach higher pressures will be explained. Along with the information provided, the reader will be guided through technological innovation in High Pressure domain. The document will cover flexible pipe armor layers design, end-fittings, dynamic behavior and High Pressure / High Temperature interactions.
Full scale testing performed to qualify 15 kpsi production risers designed to API 17J for operation in Gulf of Mexico will be detailed. To take further the understanding of High Pressure products, a focus will be made on the design and qualification performed on 4? internal diameter 20 kpsi rated well intervention lines already in-service in the Gulf of Mexico.
In the end, technical solutions and associated ongoing qualification testing to achieve 6? ID production risers for 130°C/17.5 kpsi and 150°C / 20 kpsi design temperature and pressure will be presented.
Field Development using Semisubmersible Floating Production System with Steel Catenary Risers in Western Australia Harsh Environment
Authors: Mansour Alaa M. , Bhat Shankar , Pasala Dharma , Kumar Dhiraj 
Published: June 2014

AbstractSemisubmersible Floating Production System (Semi-FPS) with Steel Catenary Risers (SCRs) is an attractive field development solution worldwide, and especially so in deeper water of Western Australia. However, SCR design is challenging in the offshore Western Australia environment due to severe cyclonic environments and persistent swells.This paper presents a comparison of three different field development alternatives that use Semi-FPS with SCRs in deepwater Western Australia. These alternative solutions are conventional semisubmersible hull design with Steel Lazy Wave Riser (SLWR), deep draft semisubmersible hull design with conventional SCRs and a novel semisubmersible hull design with conventional SCRs.The study considers a typical wet tree development for a gas field with a new build Semi-FPS host facility in 4,000 ft (1,220 m) water depth. 10-inch production and 16-inch export SCRs are considered in this study. Feasible riser designs are developed for each alternative solution.Numerical results are presented to compare the performance of the three hull designs. Project Execution Plan (PEP) and the identified risks and risk mitigations associated with the novel hull design have been addressed in this paper.Finally, differences in the hull, mooring and SCR total installed cost (TIC) as well as project execution schedule for the three alternative solutions are summarized and presented. The paper concludes with a comparison of the three Semi-FPS hull- riser choices along with a summary of the relative benefits and risks.
Safe Blind Flange Removal in Live and Congested Areas
Authors: Low Mitchel , Cameron John , Farstad Roger , Ferreira André Braz 
Published: June 2014

Abstract
The first campaign of an EPCIC (Engineering, Procurement, Construction, Installation and Commisioning) contract was a diver-less intervention to remove a blind flange under a live operational FPSO (Floating Production Storage, and Offloading vessel) turret located in a harsh North Sea environment. This was achieved by the design and build of a bespoke tool: The BFRT (Blind Flange Removal Tool).
Interfaced directly with the Remotely Operated Vehicle (ROV), the ROV docks the tool onto the flange and then controls its rotation around the flange, cutting the twelve bolts using a saw blade attached to a feeding arm. Completion of the next operation, to install a Bend Stiffener Connector (to be connected to the blind flange, enabling a riser pull-in), was very much dependent on the success and offshore feedback from the first campaign.
The initial concept was based on previous offshore experience and in-house design of rotational cutting tools. This paper will outline some of the technical challenges in creating the tool and how the use of advanced modeling software, practical onshore testing, operator feedback, and previous project experience contribute to the final delivery.
Hybrid Split VFD Poses to Significantly Extend Subsea Processing Tieback Distance
Authors: Voight Richard 
Published: June 2014

Abstract
Oil and gas operators are developing subsea production systems at greater and greater distances from their respective hosts in deepwater basins worldwide. Many of these subsea systems have the potential to include subsea boosting systems (pumping and/or compression) in these installations, which presents the need for significant amounts of AC power to be delivered over these increasing distances. Recent experience and subsequent investigation has shown that the required AC power can be delivered efficiently and cost effectively to these installations via an innovative system approach involving a split of the major components of a typical Variable Frequency Drive (VFD) system, locating the AC/DC conversion equipment at the host facility where power is generated, locating the DC/AC conversion equipment on the seabed, in proximity to the subsea boosting equipment, and connecting the two via a DC transmission cable.
Through utilization of DC power transmission, we expect to eliminate the reactive power issues and line harmonics issues associated with AC transmission. Innovational approaches such as this one will make these installations more practical and cost effective, and open the door to even further capability.
Technological Issues Related to the Identification of Submerged Prehistoric Sites
Authors: Keith Matthew , Evans Amanda M. 
Published: June 2014

AbstractLate Pleistocene and early Holocene landscapes exposed during the last glaciation have since been inundated by rising sea levels, resulting in their submergence and often subsequent burial by sediment accretion. On the outer continental shelf (OCS) in the northwestern Gulf of Mexico (GOM) the formerly exposed landscape coincides with the presence of Paleoindian and Early Archaic human populations in the region. Unlike submerged prehistoric sites in other parts of the world the emphasis in the northwestern GOM is not on artifacts or even sites, but rather on the identification of the landscapes in which archaeological sites would have been located prior to sea-level rise. The first step in identifying and verifying these features, and any subsequent sites, consists of geophysical remote sensing, especially acoustic profiling, to identify subseafloor horizons and depositional events considered conducive for human habitation. This paper will look at current methods for identifying prehistoric sites on the GOM OCS, challenges faced in identifying prehistoric sites using the most prevalent technologies, and will briefly explore alternate technologies that are available or in development that could improve our current capabilities.
Managed Pressure Drilling Probabilistic Risk Analysis: An Illustration
Authors: Zan Kun , Bickel J. Eric 
Published: June 2014

AbstractIn this paper, we present a quantitative risk analysis tool designed to enable operators to quantify and communicate the potential safety benefits of managed pressure drilling (MPD). Building on the 2008 DOI MMS report "A Probabilistic Approach to Risk Assessment of Managed Pressure Drilling in Offshore Applications" (MMS 08), we construct a probabilistic risk analysis model. This model is based on specifying deviations and their cause-consequence relationships. Particular attention is given to deviations that may be mitigated by managed pressure drilling (MPD) operations.Specifically, we illustrate the use of influence diagrams (IDs) or Bayesian networks (BNs) to assess the risk benefit of MPD. One important benefit of our work is the presentation of MMS08 using IDs, which are a much easier method of communicating complex probabilistic models. MMS08, while quite detailed, lacked many important assessments that would be required to calculate the probability of a well control incident (WCI), which was define as a kick. We supplement this missing information by making several assumptions. These assumptions limit the applicability of the analysis we present here, but not the underlying models and methods.In the case we analyze, causes vary widely in terms of how much they contribute to the risk of a WCI. This suggests that using our tool to focus on the most important risk drivers could pay large dividends. In terms of the risk characteristics of MPD, three of our top ten risks could be addressed by MPD. Eliminating all of the risks that could be addressed by MPD reduced the probability of a WCI by 22% in our illustrative example.
Installability of Umbilicals
Authors: Pereira Miguel , Ramar Pandia Raj , Dixon Mark 
Published: June 2014

Abstract
Offshore umbilical systems are essential for transmitting power and signals required to operate subsea facilities. In particular, umbilicals are made of a large number of elements with different engineering materials to accommodate constantly increasing requirements from oil and gas industry for production in deep waters and subsea processing. Often offshore umbilicals are installed using a reel lay or a carousel method and hence they are subject to large bending, axial and crush loadings during the installation process.
In order to guarantee the structural integrity and installability of umbilicals during the installation process, umbilical manufacturers have to carry out a detailed structural analysis of the umbilicals. Such an analysis requires a deeper understanding in the structural mechanics of complicated cross sections subjected to various loadings. This increases the cost and manufacturing time of the umbilicals. This paper will present a simple method to carry out a detailed three dimensional finite element analysis of the umbilicals which will help to define safe installation limits such as the minimum reel/carousel/sheave(s) radiuses, maximum installation tension and tensioner crush operating loads.
A 3 Dimensional Umbilical Simulation Tool, known as 3DUST has originally been developed by DeepSea (Dixon and Zhao, 2008), now a McDermott subsidiary. 3DUST is capable of three dimensional modelling of umbilicals and consists of pre-processing and post-processing features. Using the pre-processing feature, a modelling input deck with different materials, geometries, boundary conditions of any umbilical can be generated. This input deck is compatible with Abaqus finite element analysis software. Once the input deck is analysed, the post-processing feature can generate results with the installation capacity such as bending, axial load, crush load and ovality of the umbilical analysed, which can in turn be used to determine the adequacy of the reel lay or carousel system of the installation vessel.
The paper will demonstrate the use of 3DUST for the installability analysis of an example umbilical with original analysis carried out for providing solution to an installation challenge of the umbilical. The paper will also present the results of the example umbilical obtained from 3DUST.
A particular significance of the paper is not to demonstrate the computational mechanics involved in the analysis of umbilicals, but to address key challenges in the structural mechanics of the umbilicals and to simplify the umbilicals' analysis method by using 3DUST, a knowledge based system with capabilities including suitable finite element meshing of geometries, material assignments, defining boundary conditions and presenting relevant results. It is noted that this method has been applied to many deepwater umbilicals in West Africa, Golf of Mexico and Brazil.