bluuebunny/crossref_metadata_2025_split huggingface dataset:
Safety Systems for Subsea Applications
Authors: Curran Christopher J. 
Published: June 2014

Regulatory agencies have established certain requirements for the design, installation, and operation of offshore production facilities. This paper presents a systematization of proven practices for providing a basic safety system for subsea applications. Proper application of these practices, along with good design, maintenance and operation of the entire production facility, should provide an operationally safe system. This paper presents recommendations for designing, installing, and testing a basic safety system for subsea applications. The basic concepts of subsea safety systems, protection methods, and requirements of the system are discussed and outlined.
For the purposes of this paper, ‘subsea system’ includes all process components from the wellhead (and surface controlled subsurface safety valve [SCSSV]) to the topside boarding valve. This paper illustrates how system analysis methods can be used to determine safety requirements to protect any process component. Actual analyses of the principal components are developed in such a manner that the requirements determined will be applicable whenever the component is used in the process. The safety requirements of the individual process components may then be integrated into a complete subsea safety system. The analysis procedures include a method to document and verify system integrity. After a production subsea safety system is placed in operation, this paper discusses the procedures that should be established to verify continued system integrity.
This paper highlights the operating modes of the safety system:automatic monitoring and automatic protective action if an abnormal condition indicating an undesirable event can be detected by a sensor,automatic protective action if manually actuated by personnel who observe or are alerted to an unsafe condition by an alarm, andcontinuous protection by support systems that minimize the effects of escaping hydrocarbons or other undesirable events.. The cause(s) of the undesirable events are determined from a detailed investigation of the failure modes of the component. The safety analysis of each process components associated with the operating modes highlights undesirable events (effects of equipment failures, process upsets, accidents, etc.) from which protection should be provided, along with detectable abnormal conditions that can be monitored for safety surveillance.
The paper addresses the importance of proper analysis and design of a subsea safety system in order to focus on personnel safety, preventing releases of hydrocarbons, stopping the flow of hydrocarbons resulting from a loss of containment if it occurs as well as preventing and mitigating the ingress of seawater resulting from a loss of containment in an under pressure system scenario.
Qualification of a Subsea Separator with On-line Desanding Capability for Shallow-water Applications
Authors: Olson M.D. , Grave E.J. , Juarez J.C. , Anderson M.R. 
Published: June 2014

Abstract
ExxonMobil Development Company (EMDC) recently completed a qualification program which included a multiphase, subsea separation system for shallow-water applications. This paper summarizes the results from this qualification program.
Developments and advances in subsea processing technologies and the application of such technologies have been fueled by recent economic considerations in the oil and gas industry, as fields are maturing and operating companies strive to maintain oil and gas production. To-date, companies have executed project-specific qualification programs which take years of upfront engineering. The intent of this qualification program was to develop subsea separation technologies for the "global" subsea portfolio, rather than a specific project.
To cover the "global" subsea portfolio, a separator design was chosen that would meet separation performance targets over a wide range of operating conditions. For subsea applications, availability and reliability is critical, as unplanned intervention costs are extremely high; therefore, only certain internals were recommended to avoid plugging and fouling issues. Also, the separator was equipped with sand handling internals, including sand jetting headers and sand removal cyclones, to allow online fluidization and removal of accumulated sand. Qualification activities included the development of a subsea processing template, design validation of a multiphase separator design using Computational Fluid Dynamics (CFD) and performance tests with model fluids and "live" fluids, and performance tests on the sand handling equipment. High-level results from these tests are shared.
Prior to the qualification programs, experience with subsea separation technologies, and subsea processing as a whole, within ExxonMobil was limited to being an active partner with subsea processing projects such as Tordis and Pazflor. Following the execution of the aforementioned qualification programs, technical risks have been mitigated, such that it is now possible to be confident in applying these technologies in the "global" subsea portfolio. This will enable ExxonMobil to reduce the cost and schedule impact of upfront engineering on future subsea processing projects. In the ever-changing business environment of the oil and gas industry, this may become a preferred approach to bring unproven technologies to maturity when the business need is well-established.
Low Motion Semisubmersible Hull for Dry Tree Application
Authors: Kyoung Johyun , O'Sullivan Jim , Kostas Lambrakos , Whan Kim Jang , Ermon James 
Published: June 2014

Abstract
For three different marginal fields with different payloads, two variations of Technip's wet tree HVS semisubmersible are designed for dry tree application and evaluated on the basis of riser tensioner stroke and deck acceleration. These dry tree suitable hulls also have reduced vertical heave motion at the SCR porch and improve quayside integration and commissioning of topsides to the hull.
A key element for the dry tree platform is the riser tensioning system which supports the direct vertical production risers from a subsea wellhead to a topside production tree. These riser tensioners provide additional hull heave stiffness, and effectively reduce the overall natural heave period of the hull. Conventional semisubmersible designs have excessive heave response in harsh environments, resulting in tensioner stroke ranges that are beyond the stroke ranges of field proven conventional riser tensioner equipment.
The HVS class semisubmersible with reduced heave and VIM response was chosen as the basis for the dry tree semisubmersible designs in order to achieve riser tensioner stroke ranges within the capability of field proven riser tensioners. The main characteristic of the HVS class of semisubmersible is the redistribution of displacement from the pontoons to the lower part of the column. This is accomplished with a column step, which has the appearance of a blister, located partially around the lower part of column. This redistribution reduces the vertical hydrodynamic excitation, and the heave response. The column step breaks also the coherence of the vortex shedding along the length of column and consequently suppresses the vortex induced motion. The dry tree adaptations of the HVS class semisubmersible include pontoon plates that increase the heave natural period through added mass, and the outcome is reduced heave motion for seastates with high peak periods. The pontoon plates are simple structures to fabricate and have additional benefit of enhancing structural rigidity. The contribution of the pontoon plates to the hull steel weight is minimal. With optimal design of the pontoon plates, the resulting dry tree hulls support the top tensioned risers without the need of a keel guide.
The dry tree hull forms have been designed using Computational Fluid Dynamic (CFD) analysis. Extensive CFD work was performed in order to finalize the dry tree designs.
Seabed Friction On Carbonate Soils: Physical Modelling of Axial Pipe-Soil Friction
Authors: Boylan N.P. , White D.J. , Brunning P. 
Published: June 2014

Abstract
This paper is concerned with the ‘friction’ and ‘sliding resistance’ that can be mobilised on the unusual carbonate sediments prevalent across many parts of the world, including Offshore Australia. Physical centrifuge model testing was conducted to evaluate the axial pipe-soil resistance on a soil obtained from the North West Shelf, offshore Australia. Tests were performed at a range of speeds, spanning drained/undrained conditions, interspersed with consolidation periods. The resulting axial friction factors are generally higher than is often assumed in conventional design practice for pipeline end expansion or buckling and walking analysis, which is consistent with the high friction angles and dilatancy of these angular carbonate soils. In addition, the results demonstrate the effect that soil drainage response and history of pipeline sliding movements can have on the axial-pipe friction. Overall, the results highlight the importance of making site-specific assessments of seabed sliding resistance, rather than rely on non-site-specific results (particularly from different regions) that may display a very different soil response. Lastly, recommendations are made for design assessments of the sliding resistance of carbonate soils.
Core scale Evaluation Of Geomechanical Property Related To Gas Production From Gas Hydrate Deposits In The Ulleng Basin, East Sea, Korea
Authors: Lee Joo Yong , Lee Jaehyung , Kim Se Joon , Ahn Taewoong 
Published: June 2014

Abstract
The production of natural gas from gas hydrate deposits poses chalenges such as assessing hydrate recovery rates from physical properties and geological structure of the hydrate reservoir, securing the economic viability of produced gas from a particular resource, and keeping process safe from geomechanical impacts from hydrate dissociation. The macro scale behavior of sediments during production operations, such as particle migration, fluid flow, and deformation behavior, is governed by particle characteristics, fabric formation environments, and the resulting fabrics. The geotechnical terms for characterizing the grain size distribution are useful tools for estimating geotechnical parameters in the absence of an extensive set of the geotechnical laboratory experiments. In this manuscript, the grain size distributions of sediments from the Ulleung Basin will be utilized to characterize geomechanical behaviors induced by the production operations at gas hydrate-bearing sites in the Ulleung Basin, where pore-filling GH have been found in the intercalated turbidite sands. According to the analyses on the grain size distributions, the particle migration in coarse grained layers during production necessitates proper measure for sand productions, while fine grained layers are mostly self-filtering. The hydraulic conductivity in pore-filling gas hydrate-bearing layers is relatively low in comparison with those from conventional gas reservoirs, and the conductivities at layers above GH layers are low enough to function as barriers.
API 17G Specification for Subsea Well Intervention Equipment
Authors: Stawaisz Ray , Muff David Anthony , Skeels Brian 
Published: June 2014

This paper overviews the proposed API 17G Specification, assisting the reader in navigating the lengthy document. The results of this paper for the reader will be a simplification of the proposed Specification and an understanding of the safety philosophy and strategy which is the core upon which system analysis, equipment design, equipment qualification and material/manufacturing specifications are based. The document stops short of addressing HPHT until the task group has time to review and incorporate API 17TR8.
This proposed specification is intended to illustrate current technology and design practice along with structuring its format to accommodate future intervention technologies and hardware. It is also intended to provide the necessary safety review and campaign planning tools needed by of the offshore community for subsea well intervention and workovers, similar to those now being incorporated into offshore floating drilling practices.
Managing the Risk of the Unknowns: Åsgard Subsea Compression Qualification Program
Authors: Hedne Pål 
Published: June 2014

Abstract
The Åsgard field was started up in 1999 and comprises the Smørbukk oil and Midgard gas assets. Midgard is developed with three subsea templates located approximately 45 km (31 miles) from the Åsgard field centre. Additionally, the gas field Mikkel located nearly 40 km (25 miles) further away is tied back to Midgard. To extend the life time of the Åsgard Field and achieve Increased Gas Recovery (IGR), boosting of well stream is necessary. Since 2005 Statoil has matured two concepts in parallel, a compressor platform and a subsea compressor facility. In October 2010 it was decided to go forward with the subsea facility. The Åsgard Subsea Compression (ÅSC) project is now building the world's first Subsea Compression Station (SCSt). ÅSC will be ready for operation in 2015 and secure production of 282 MMboes from the Åsgard field up to 2029.
The ÅSC SCSt will include two individual compressor train installed in a shared template with a total weight of 5100 tonnes, a footprint of more than 3300 m2, and height around 26 meters. The project includes novel technology especially related to gas compressors and subsea power distribution.
To mature the concept, a comprehensive Technology Qualification Program (TQP) was initiated in 2007 covering activities related to the following main building blocks:Process modules (coolers, scrubber, pump and compressor)Power system (long step out with topside Variable Speed Drive (VSD), transformers, HV swivel, connection system, umbilical / power cables)Control system (process, AMB and anti-surge)in addition to Hot-tap, remotely installed retrofit tee on the Midgard pipeline
The total qualification program included nearly 50 activities. Attention was given to define the TQ's in terms of gap analysis and failure modes, to ensure that the acceptance criteria reflected the necessary gathering of evidence to proof the equipment fit for service. The qualification has been done in collaboration with a series of vendors and research institutes. A large scale laboratory facility has been built at Statoil's R&D centre K-lab at Kårstø for testing gas compressors and long step-out power systems. The results from this work have been of crucial importance in maturing the subsea compression concept to the necessary level.
Challenges Associated with Electrical and Optical Cable Terminations and Connector Systems for the Drilling Industry
Authors: Brown Gary , Lewis Karen 
Published: June 2014

Abstract
The challenges associated with the design, manufacturing and testing of underwater electrical and optical cable termination and connector systems for the Drilling Industry are vast and far-reaching. No longer are connectors only being supplied, but also complete systems, such as fully terminated umbilicals. For connectors that need to be installed in the field, sometimes in extremely arduous conditions, designs need to overcome the effects of pressure and temperature at ultra-deep sea-depths and to be strong enough to withstand the rough handling topside and rough environmental stress of being within close proximity to drilling systems activity. To meet the challenges and enable continuous improvements, connector companies cannot focus solely on connectors, they must see the future of cable terminations and connectors and their synergetic relationship to the umbilicals and cables.
Olympus TLP- Design and Construction Embedded in a "I Care" Culture
Authors: McGlothlin Terry 
Published: June 2014

Mars B's approach to HSE is embodied in the HSE Vision and Values, adopted early in the project's design phase:
This consistent focus on a caring culture and managing risks to ALARP has manifested itself in a robust design with novel process safety design improvements, notably in the areas of passive hull, riser isolation, temporary refuge integrity, and drilling rig automation. In fabrication, installation, and commissioning, the project has built on the safety successes of the Perdido Project, with nearly a 25% reduction in recordable injury rate.
Specific actions taken during project planning and execution have enabled Mars B's HSE successes in both personal and process safety:Process Safety EnablersPersonal Safety EnablersEarly identification of Safety Critical ElementsClear ownership of Safety Critical Elements within the Design TeamPerformance Standards, including robust verification and assurance processes.Hazard Management Hierarchy inherent in design decisions.Front-End Loading of Technical Safety requirements.Transparent process for ALARP decision making.Early and frequent HSE engagement with contractor managementEmpowered and competent site teams, fostering a culture of initiative and interventionFocus on frontline leadership accountability and commitmentVisible and Felt Leadership: tangible demonstration of care for workforce (leadership site visits, recognition events, PPE, training opportunities)
Mars B's approach to HSE is embodied in the HSE Vision and Values, adopted early in the project's design phase:
This consistent focus on a caring culture and managing risks to ALARP has manifested itself in a robust design with novel process safety design improvements, notably in the areas of passive hull, riser isolation, temporary refuge integrity, and drilling rig automation. In fabrication, installation, and commissioning, the project has built on the safety successes of the Perdido Project, with nearly a 25% reduction in recordable injury rate.
sgard Project - Another Step Versus the Full Subsea Process Plant
Authors: Micali Salvatore 
Published: June 2014

Any new techniques that can improve traditional methods of production and offer increased recovery are eagerly sought after by the oil and gas industry. Among those, subsea gas compression systems are being recognized as the best solutions for both improved recovery and access to stranded reserves.
Indeed, after several years of design, qualification and testing, today the subsea gas compression technology is an economically feasible way to compensate the gas reservoir pressure depletion.
This paper will present the Åsgard project, the first commercial project applying the subsea compression technology. Considering the complexity and at the same time the robustness of the system proposed, with this project the subsea technology will do another important step to reach the full subsea process plant vision.
Iceberg Scouring on the Norwegian Continental Shelf
Authors: Lien Reidar 
Published: June 2014

ABSTRACT
This paper is a condensed version of parts of a Dr. ing. thesis to be presented during 1983 (1). The first part of the paper deals with the regional distribution of iceberg scouring on the Norwegian continental shelf, and some general aspects related to it. The second part deals with iceberg scouring as a 1ocal phenomenon and its relation to the sea floor topography, sediment distribution, and geological and geotechnical properties of the sediments.

INTRODUCTION
Iceberg scouring on the European side of the Atlantic Ocean was first reported in 1973 (2, 3). The investigations reported were carried out north and west of the British Isles (3) and in the vicinity of the Norwegian Trough (2). Belderson and Wilson (2) suggested that the iceberg plough marks also should be found in parts of the Norwegian slope and shelf areas shallower than 500 m. Later these features have been described from several areas of the Norwegian shelf (4,5,6,7,8).
In areas with scars made by grounding icebergs, they highly influence the sea floor conditions both With regard to the topography of the sea floor, and the geological and geotechnical properties of the sea floor sediments. These are all decisive factors, both with respect to technical solutions and economy, when structures or pipelines are to be installed on the shelf. The shapes and sizes of the scars vary considerably. They have been recorded more than 20 m deep, more than 250 m wide and several kilometres long. They are all fossil.

GENERAL DISTRIBUTION OF ICEBERG SCOURING
The map in Fig. 1 gives an overview over the distribution of iceberg scouring on the Norwegian shelf from about 58 N to about 72 N. The map is mainly based on side-scan sonar, boomer, and sparker records obtained during the Continental Shelf Institute's regional map- ping program. This program has a general profile grid (Fig. 2) where the main profiling directions broadly are perpendicular to the coast, and the crossing profiles run parallel to the coast. The distances between the main lines are about 10 km, and the crossing lines are about 25 km apart. Besides the information from this program, data from site surveys and other special investigations are also comprised.
As it can be seen from Fig. 1, large areas of the continental shelf are infested by iceberg scouring. As Belderson and Wilson (2) showed, there are iceberg scars on both sides of the Norwegian Trough (Figs. 1 and 3), but it is especially on the eastern slope of the trough and northward that we find the most intense scouring. Between the 61, parallel and the 71, parallel about 55% of the shelf shallower than 500 m are iceberg scoured. The iceberg scouring is mainly recorded in water depths between 100 m and 500 m. From the distribution map in Fig. 1, we can observe that, in general, the continental slope and the protruding banks on the shelf were most exposed to grounding icebergs.