bluuebunny/crossref_metadata_2025_split huggingface dataset:
Subsea Compression - Designing and Building a Subsea Compressor Station
Authors: Storstenvik Anders 
Published: April 2016

The Åsgard Subsea Compression is a high capacity system, designed for large flow rates and pressure ratios. The project has worked towards high ambitions of reliable, efficient and flexible operation. The Åsgard Subsea Compression is a platform: To a large degree, the subsea compressor station extends towards the capacity and flexibility of a conventional topside compressor platform. More importantly, it provides a technology and experience platform for both more advanced and broader applications, yet also simpler and leaner solutions.
This paper dives into the trial and tribulations from concept to detailed design, fabrication and testing. All were executed within the framework of one contract in an EPC execution framework. Examples will highlight critical activities, both anticipated challenges and issues not foreseen at the outset of the project.
Lack of flexibility in future modification is a general objection to the subsea factory. The Åsgard compressor station has a long operational life and the production profile varies significantly throughout the whole life cycle. The paper will discuss how future functionality can be included in initial design or, if best suited, provisioned for future stages.
Technology qualifications have been handled with the rigor and timing required in established industry practises. However, in an EPC execution framework, even smaller "first of" engineering or -designs will disturb the project's pace; eventually demanding "out of sequence work" to recover quality and progress. The paper presents some "first-of's" and discusses the dependency towards the EPC execution framework. This also includes external interfaces and main procurement activities.
The compressor station is inherently more multidiscipline than a conventional subsea delivery. One could say that it represents a "platform on the seabed" in terms of process functionality. Therefore engineering tools, methodology and expertise from topside projects has been utilised in the work. The experience harvested by use of integrated systems for schematics, 3D modelling and engineering registers will be summarized and concluded.
Finally, the organisation set-up and development for the various project phases will be discussed, in particular with respect to follow-up towards main procurement activities, fabrication, manufacturing, completion/testing and commissioning support.
An Analytical Approach to Predict the Fatigue Life of Flexible Pipes Inside End Fittings
Authors: Campello G. C. , de Sousa J. R. M. , Vardaro E. 
Published: April 2016

The offshore operational experience has shown that the flexible pipe end fitting (EF) may be the weakest point in terms of fatigue resistance of the tensile armor layers. The findings observed in dissections from risers which were in operation or subjected to qualification tests reveal that there is a key point with respect to fatigue inside the end fittings. This point corresponds to the section in which the wires of the tensile armors are subjected to significant plastic strains caused by the end fitting assembly process. Thus, this study aims to propose an analytical approach to predict the fatigue resistance of flexible pipes focusing on their terminations.
A local analytical model is employed to predict the stresses induced in tensile armor of the pipe due to the end fitting assembly and also during operation. These stresses are used in conjunction with a previously detailed approach that is employed to compute the fatigue resistance of flexible pipes. The methodology is validated by comparing its results to several real scale prototype tests.
The results obtained during validation showed that the application of this methodology in calculating the fatigue life has low variability and therefore the failures observed in the qualification tests are well predicted. This methodology has been successfully used by Petrobras in flexible risers life extension.
Fatigue Assessment for Pressure Armor Layers Subjected to Cyclic Pipe Cross-Section Ovalization
Authors: Chen Y. G. , Liu J. , Zhu L. F. , Tan Z. M. 
Published: April 2016

Abstract
A flexible riser is typically protected from over-bending at the hang off region by a bending limiter, i.e. a bend stiffener or a bellmouth. The pipe will be forced into contact against the bending limiter at one side during bending. As a result, the side contact load may deflect the pipe cross-section and induce some additional stress on the pressure armor layer. Such additional stress is dynamic in nature and is anticipated to induce fatigue damage in combination with other dynamic stresses caused by tension variation and pressure for example.
This paper highlights the mechanism governing potential pipe cross-section ovalization, and subsequent stress alternating and fatigue damage of pressure armor under dynamic loadings. Also presented in this paper is a procedure and technique for capturing such induced pressure armor damage in the pipe design process. It is noted that the pressure armor typically consists of strips with a profiled cross-section wound almost circumferentially. A theoretical approach is presented to evaluate the pipe cross-section ovality by considering the resistance from governing strength components such as carcass and pressure armor, and to calculate such induced stress variation and subsequent fatigue. This theoretical approach taken has been validated by FEA models and calibrated against a number of full-scale dynamic tests with pipe samples ranging from 4.75 to 16-inch ID. The methodology was third party reviewed and approved and deployed for riser system design and analysis.
The Future State of Completions for the Lower Tertiary in the Gulf of Mexico
Authors: Techentien Bruce , Ingram Stephen , Grossmann Andreas 
Published: April 2016

The Wilcox formation in the Lower Tertiary is an interesting and challenging development. The industry is currently seeking ways to increase efficiencies, increase production, and optimize performance of this reservoir. This paper discusses the current status in generation V single-trip multizone completions as well as future prospects to predict industry options for the formation.
This paper seeks to spur the industry into thinking about the future cost benefits and management of change necessary to design solutions for this unique development. Regarding Lower Tertiary wells, operators sometimes assume the wells are similar to the Wilcox formation in South Texas. However, studies indicate these wells should be treated like other Gulf of Mexico (GOM) wells, and they do require sand control. Is the industry willing to take these technical development risks? If unique solutions are proposed, what preparations are necessary, and how should planning proceed?
There are unique solutions that operators can apply to the deepwater GOM as well as alternative solutions, processes, and procedures developed for land applications that can be adapted to the deepwater GOM. Land production has adopted the horizontal approach for efficiencies, but is this the correct approach for deep water? The multilateral approach is an interesting option that has been applied in other offshore environments, but is this a concept adaptable for the Lower Tertiary? How can monitoring and control be applied to these two concepts from land applications? How do operators take industry knowledge and apply it to the unique offshore environment of deepwater and subsea completions?
The ultimate goal of this paper is to examine these questions and initiate the thought process of how the industry can optimize the returns from the Lower Tertiary by increasing production and recoverable reserves through technology and reservoir management.
The Successful Development and Installation of a New Single-Trip Multizone Completion System Developed for the Deepwater Gulf of Mexico Lower Tertiary Formation
Authors: Grigsby Tommy , Jannise Ricki , Goodman Archie , Techentien Bruce , Schexnailder Michael , Navaira Guy 
Published: April 2016

Abstract
Development of the Wilcox stacked oil sands in the Lower Tertiary fields in the Gulf of Mexico (GOM) requires zonal stimulation; however, when the decision was made to produce this formation, the stacked sand-control systems currently available would have been cost prohibitive. Thus, a special team was commissioned to develop a single-trip multizone completion system to address the challenges of producing this ultradeepwater GOM field.
This paper chronicles the development, qualification, and installation of a new one-trip high-rate fracture system that meets the needs of cased-hole installations in the Lower Tertiary formations with well depths reaching 28,000 ft TVD, as well as in cased-hole shallow-depth wells in the Asia Pacific area.
A dedicated development team began tool-system development in January 2007. The first systems integration test (SIT) was conducted in December 2007 after only 11 months. The successful SIT led to the assignment of three land wells by a major international oil company to prove out the multizone system. After two successful installations, the third installation was eliminated, because the multizone system was classified as operationally ready.
Drilling issues lead to the plugging and abandonment of the planned inaugural ultradeepwater installation. The operational moratorium in the GOM in 2010 also changed the original target wells. The first commercial cased-hole installation was run in the Asia Pacific area in a shallow-depth well environment using water-pack treatments. Subsequently, multiple ultradeepwater installations have been performed to date.
Lessons learned from the SIT process and from the initial installations that included the ultradeepwater Lower Tertiary fields are presented.
CFD Predictions of FLNG BOG Including the Influence of Filling, Offloading, and Vessel Motion
Authors: Yu Kai , Ge Zhongfu , Korpus Richard 
Published: April 2016

Abstract
The accurate assessment of boil-off gas rate is essential for the design of FLNGs and LNG carriers. Unfortunately, existing engineering methods used to estimate these rates are fairly primitive. Current methods can account for conductive heat transfer but the details of convective mixing are not included. Since convective mixing can be the larger of the two, better methods are needed to account for the impact of LNG movement due to filling, vessel motions, and off-loading. Modern CFD methods are able to account for all these effects, and this paper describes the development of one such technique using the commercial software package StarCCM+. The approach builds a 3D CFD model for one entire tank, including insulation, filling and discharge pipes, gas vents, and (if necessary) cofferdam areas and internal tank structure. Hydrodynamics, thermodynamics, heat transfer through the insulation and phase change are all computed simultaneously. Results are included for two distinct cases: one depicting a filling operation and one simulating the effect of vessel motions. In each case, 3D, time-dependent distributions of temperature, fluid velocity, pressure, and LNG volume fraction are presented. In cases where gas pressure increases beyond a preset limit, time histories of vented gas property and flow rate are given at the vent. Videos are available that demonstrate the complexities of spatial and temporal variations. Accuracy is demonstrated by comparing to known model problems for which validation data exists, and best practices are provided to assist other practitioners start their own applications.
Comparative Study of Different Erosion Model Predictions for Single-Phase and Multiphase Flow Conditions
Authors: Parsi Mazdak , Kara Mustafa , Sharma Partha , McLaury Brenton S. , Shirazi Siamack A. 
Published: April 2016

Abstract
There are various equations and models for assessing erosion for both single phase and multiphase flow scenarios. Consequently, this study was performed to shed light on the issue of which models provide better predictions. For the single phase situation (air-sand flow), Computational Fluid Dynamics (CFD) erosion modeling in a direct impact geometry was conducted, and the performance of four different erosion equations was scrutinized. On the other hand, for the multiphase flow scenario, churn/annular multiphase flow regimes, that can be highly erosive when sand is present within the piping system, were selected to examine the accuracy of six different widely-used multiphase flow erosion models. For both cases, the modeling results were compared to available experimental data.
For the first part of the study, ANSYS FLUENT 16.1 was used to perform CFD-based erosion modeling including flow modeling, particle tracking, and erosion calculation. For the other part, several codes were employed to investigate six empirical/mechanistic erosion models including: 1D churn model, 2D mixture model, multiphase model, annular model, DNV GL model, and Salama model. The University of Tulsa SPPS software and the DNV GL Erosion Tool were used for this part. Furthermore, the Salama model was coded.
It was revealed that under air-sand flow conditions, Arabnejad et al. (2015a) mechanistic model provided the best results (15% error compared to experimental data). For the multiphase flow part of the study, it was found that regardless of particle size, the multiphase erosion model underpredicts all erosion data, and the 1D churn, Salama and 2D mixture erosion models significantly overpredicted the experimental data. Moreover, the annular and DNV GL models provided the best predictions among all six models.
A literature survey reveals that there is a limited number of comparative studies for erosion prediction models. This study, therefore, should be of interest to a broad readership including but not limited to erosion, corrosion, multiphase flow, and flow assurance.
The World's First Deepwater Multiphase Pumping Application above 100bar ?P, Technological Risks and Mitigations
Authors: Bibet Pierre-Jean , Huet Nicolas , Âsmul Vidar 
Published: April 2016

The Girassol Resources Initiatives (GirRI) is a major brownfield deepwater project, which seeks to optimize the Girassol FPSO production. It is also the third subsea boosting project being developed offshore Angola by Total, the operator, and OneSubsea, the contractor. High boost multiphase pumps (MPPs), with an operating ?P of 110 bar at 53% GVF are deployed subsea on two existing deepwater oil production loops to enhance the Rosa field reserves and production, a world's first for the oil and gas industry.
Before using a new pump at the leading edge of technology, an extensive qualification program and a series of stringent acceptance tests were waranted to demonstrate the soundness of the design.
Developing the first high boost MPP application also required revisiting the subsea pumping station architecture to mitigate as many of the risks as possible associated with pumping a multiphase fluid at high pressure.
This paper details how the Project Team addressed the risks associated with multiphase pumping above 100 bar ?P, and how the contractor met all the requirements specified by the operator to build a robust one design-fits-all pumping solution.
Mitigating Gas in Riser Rapid Unloading for Deepwater Dual Gradient Well Control
Authors: Yuan Zhaoguang , Morrell Dan , Sonnemann Paul , Leach Colin 
Published: April 2016

In deepwater dual gradient wells, if gas comes into the riser, a rapid unloading event may occur if removal of the gas is not carried out properly. Oil based muds present an even greater challenge when compared to water based muds to avoid gas in riser events, because the gas dissolves in the mud and may not be detected until it breaks out inside riser near the surface.
A study using a dynamic multiphase flow software simulated a rapid unloading event and determined the gas fraction in the riser annulus and the effect on riser fluid levels. New procedures, such as shut-in the riser or proactively applying surface pressure were simulated to evaluate effectiveness of riser-top equipment to mitigate risks of rapid riser unloading. The effects of gas volume, and mud type (water vs. oil based mud), on water hammer and riser top pressure during the shut-in were analyzed using a simulated case with a riser in 8,000 ft of sea water.
The analysis shows there is no significant pressure increase at the moment of rapid unloading in a shut-in well. The simulation results reliability is verified using a field test conducted in 1,200 ft sea water. The simulation results show it is possible to safely manage gas-in-riser events for large gas fractions using available managed pressure drilling and riser gas-handling equipment.
It should be possible to safely and efficiently manage events involving even relatively large gas influxes in risers by use of new proposed procedures, which mitigate the rapid unloading and can help industry develop new guidelines for deepwater drilling operations.
Subsea All Electric Technology: Enabling Next Generation Field Developments
Authors: Winther-Larssen E. , Massie D. , Eriksson K. G. 
Published: April 2016

This paper will show that utilizing all-electric standardized and configurable hardware, together with appropriate software building blocks, an all-electric Subsea Production System will be a cost competitive alternative to electro-hydraulic systems.
By integrating automotive and telecom competence with subsea expertise, it has been possible to implement a rigorous design-to-cost mindset in the development of the various all-electric system building blocks.
All-electric hardware and software will give large benefits both in terms of reduced CAPEX and OPEX (in addition to improved health and safety as well as increased functionality) derived also from applying subsea and downhole all-electric technology solutions on a wider scale.
For all electric systems, the following general cost benefits have been estimated:
CAPEX
OPEX
HSE, (Safety and Environment in particular)
Increased functionality
Reliability
Flexibility
Electric actuation, sensing, integrated power management and control offer the promise of smaller, lighter and more cost effective subsea production systems. They also offer the potential for more precise measurement, control and maintenance monitoring over time over their hydraulic counterparts, which enables planned maintenance of equipment, with significant benefits in terms of reduced OPEX.
Introducing Holistic Approach for the Design and Operation of FLNG Development
Authors: Kheireddine Houssein , Chen Derek , Timms Jennifer 
Published: April 2016

As is the case with any new technology, floating LNG includes uncertainties and unforeseen risks. With the methodology proposed in this paper, some of these risks may be identified and mitigated in design and operations. Specifically, the methodology will quantitatively and holistically assess the entire system's performance over the design life. The results of such a study improve stakeholder confidence in the proposed design, ensure that the limited space on the vessel is used effectively for production, prepare the system for operations by identifying and addressing potential resourcing and operational issues, and project the effects of gas well depletion on the system performance.
DNV GL will use TARO software to execute the proposed methodology. With this software, it is possible to evaluate equipment in terms of its contribution to planned and unplanned downtime. Repair delays, maintenance crew size and availability, spare parts availability, flaring limitations, weather conditions, and limited LNG/LPG/condensate working volumes which impact production can also be captured in the model. On an entire-system level, TARO can model the dynamic relationship between the processing facility, storage/loading system and shipping schedule. The results of TARO would be used to minimize inventory level and optimize LNG carrier sizes and numbers. Depending on the type of negotiated LNG sales demand contract, demurrage cost can also be quantified.
The results generated serve as a feed to cost-benefit analyses used to determine whether or not the additional cost associated with the proposed design/operations modification is justified against the incremental increase in production. This will provide managers with decision support, not only from an efficiency standpoint, but also from an economic standpoint.
Geophysical Reservoir Characterization and Monitoring at Brazilian Pre-Salt Oil Fields
Authors: Johann Paulo Roberto Schroeder , Monteiro Rubens Caldeira 
Published: April 2016

Abstract
In 2006, the Brazilian pre-salt oil field province was discovered from a pioneer well at Lula oil field. The province is characterized by carbonate reservoirs, microbial and coquina rocks, buried at a depth that surpasses 5,000 m, distributed in the Santos and Campos sedimentary basins, located at the east Brazilian coast. During the past ten years, upon the discovery of several oil fields and their respective productions, which now exceeds 1,000,000 boepd, there has been major progress in the application of new geophysical technologies with greater impact on the reservoir characterization and monitoring, in both exploratory and development production phases.
This paper will present such progress made by the application of geophysical technologies in the acquisition, processing and interpretation stages oriented to the reservoir characterization and monitoring.
More specifically, in regards to the reservoir characterization area this paper will address the new technologies that influenced the definition of the external and internal geometries of carbonate reservoirs, both from stratigraphic and structural point of view.
New methods of seismic characterization of reservoirs, from the elastic inversion, the extraction of geometric attributes and the use of new technologies to reveal geological fractures corridors will be therefore detailed. Another major challenge described will be the implementation of 4D seismic technology for monitoring the behavior of fluid motion and pressure variation in the Brazilian pre-salt carbonate reservoirs.
As for the reservoir monitoring, this paper will show the progress of the pioneer project of 4D seismic monitoring of microbial carbonates through NODES technology in an ultra deepwater area where the development of production applies the alternating injection of water and gas (WAG).
Finally, we will present remaining geosciences challenges and the opportunities for the use of new technologies that can help us in the reservoir characterization and monitoring of these Brazilian pre-salt carbonate reservoirs.