bluuebunny/crossref_metadata_2025_split huggingface dataset:
Modeling and Simulation; Subsea Stepout and Tieback
Authors: Korn Milton , Mesineni Shilpa , Hu Weiguang 
Published: April 2015

Abstract
Recovery of subsea resources located at great distances from shore at great depth often envision some processing of the recovered product on the sea floor prior to transportation to a floating or onshore facility. Processing and transportation efforts require that energy be transported at the required rate and controlled to facilitate stable operation. In sea floor processing facilities, energy consumers can be expected to be deployed down hole at primary pumping/compression and booster pumping/compression stations on the sea floor as well as being located along the length of the tie-back (pipeline) to the onshore receiving facility.
Electrical supply is likely to consist of a subsea transmission line running (step-out) alongside the tie-back and being periodically tapped along the length as required to deliver power to booster pumping/compression stations. The length of the transmission line, various global loading scenarios, and varying loading at specific receiving points is a challenge for maintaining power quality and stability at each receiving point, where energy/power is drawn to supply loads.
ABS has built preliminary models of subsea pipeline tiebacks and electrical step outs. Engineers have performed simulations of energization of the step out, and have studied step-out electrical transients. Future work will focus on the study of steady state and slow dynamic pipeline flow, power system characteristics and the interaction between the hydraulic and electrical systems refining the models to include more of the hydraulic characteristics and electrical characteristics of the coupled systems to increase the fidelity of the simulation.
Bonga Northwest Subsurface Development – Planning, Execution and Uncertainty Management
Authors: Pokima Sophie , Afolabi Raphael , Fakunle Oludayo , Njoku Chukwueke , Okonkwo Paulinus 
Published: April 2015

The Bonga North West (BNW) field is located in Shell operated Oil Mining Lease (OML) 118, a deepwater development in Nigeria. This paper presents the BNW subsurface development strategy and the associated uncertainty management both at planning (Field Development Plan -FDP) and execute phase.
The first development in the OML 118 acreage is the Bonga Main field which came on stream in November 2005 via a Floating, production, storage and offloading (FPSO) vessel. The development strategy of the block is to maximize value from the asset, ensuring that the hub is kept full by developing reservoirs in the nearby fields while optimizing production from the block. In pursuant of this strategy, detailed subsurface evaluations were carried out to estimate expected recovery of the nearby fields as potential tie-backs to the Bonga Main FPSO. The size of nearby discoveries and proximity to the FPSO were two key parameters used to develop the OML 118 development strategy.
BNW was discovered in 2003 following the detailed interpretation of 3D seismic acquired in 1995 on the acreage. Integrated evaluation across key disciplines established commercial viability of the project. This, coupled with a detailed geo-hazard study, formed the basis for the 2011 BNW FDP. The FDP proposed the field being developed with nine wells in two phases of drilling. The development phasing was driven by the requirement to manage the field uncertainties by gathering additional data. The first phase development involves six wells (four oil producers and two water injectors).
BNW leveraged on its close proximity to the existing Bonga Main infrastructure and was approved as a subsea tie back development to existing Bonga Main FPSO. The FDP enabled a robust management of challenges such as shallow gas occurrence, structural/depth uncertainty, stratigraphic/reservoir development, reservoir connectivity, fluid prediction in the shallow horizons, bore hole stability and overburden shale issues encountered in the execution phase. Also a new technology that targeted managing of impairments in water injection wells experienced in the operation of Bonga Main field was also successfully deployed in the BNW field development. All Phase 1 development wells have been successfully drilled and several learnings from this project have been documented and will be used on projects going forward.
Safety Case in GoM: Method and Benefits for Old and New Facilities
Authors: Carval Julia , Das Bibek 
Published: April 2015

Abstract
The purpose of Bureau of Safety and Environmental Enforcement (BSEE)'s Safety and Environmental Management Systems (SEMS) is to enhance safety of operations in the Gulf of Mexico (GoM) region. One of the four principal SEMS objectives is to encourage the use of performance-based operating practices. However, the current U.S. Regulatory framework for offshore operations in GoM does not provide the adequate tools to focus on the specific risks associated with a facility. The adoption of a Safety Case regime would steer the operations in the GoM towards this goal. Operators could take over the Safety Case as a significant input for the development of their Risk Management and Asset Integrity Management (AIM) programs for existing operating facilities as well as new facilities being planned.
The paper discusses the application of a Safety Case and how the Operator can demonstrate that the major safety and environmental hazards have been identified, the associated risks are estimated and how these risks are managed by achieving a target level of safety. Throughout the Safety Case road map, the identification of the Safety Critical Elements (SCEs) and the associated Performance Standards represents one of the corner stone of the AIM Strategy. Introduction of the Safety Case would not imply a complete overhaul of the current Regulation, but would lead to a continuous and adequate enhancement of the Regulatory requirements towards a performance-based approach. It would include a prescriptive-based policy, combined with a performance/goal-oriented process, considering the specific risks inherent to the installations and the demonstration of how these risks are managed.
With help of an example the paper discusses how application of Safety Case for existing facilities would highlight particular risks that may have been misjudged, taking into account the current state of its installations and the actual operational procedures in place. Further, this paper shows how existing Risk Management and AIM systems could be revised based on identification of SCEs and definition of the associated Performance Standards. This would also give the Regulator a quantified picture of current operations in the GoM and assist in re-defining the distribution of its resources and efforts in order to have an efficient review and verification impact.
For the new facilities, the introduction of the Safety Case at the early stages of design would ease the integration of the overall risk management plan at each level of organization. The Regulator would have the ability to cross-analyze the risk results arising from the Formal Safety Assessment studies with the risk management plan drafted by the Operator. This paper investigates the possible integration of a performance/goal-oriented regime into existing Risk Management and AIM systems.
Integration and Flawless Start-Up of Different Systems in Bonga North West Project
Authors: Ilesanmi Olaniyi , Katimi Theo Ekiyor , Erhabor Kingsley , Ikhenebome Thomas , Kanu Chika , Mbonu Obinna , Mehta Tejus , Ofoni Sylvester 
Published: April 2015

The Bonga North West Project (BNW) is the first subsea extension to the existing Bonga Main subsea facility, as well as the first major subsea tie-back to be executed in the Nigerian sector of the Gulf of Guinea deepwater. This paper provides a detailed discussion of the process of integrating the new systems comprising subsea producers, injectors and all the ancillary facilities, to an existing, but different, Original Equipment Manufacturer (OEM) system. It will also give a detailed explanation of the intermediate systems engineered to achieve this integration, and the process used for successful integration of the two different systems. The planning and deployment of a new Completions Management System for the commissioning of the new facilities, and the strategy adopted to achieve a flawless start up will also be presented in this paper.
To ensure a flawless start-up, Shell Project standards were employed. A Simultaneous Operation (SIMOPS) emergency shutdown was carried out to check the integration of the new subsea infrastructure as part of final checks performed prior to start up.
To enable seamless integration between the two different subsea systems, staged system integration and verification tests were planned and executed to ensure that each component performs as per intended design. A series of assurance activities were carried out to demonstrate alignment between design intent and healthy operations of the new subsea system, for the following:
Correlation of field data with design analysis for both the existing and new systems
Benchmarking the performance of the new integrated system against the old system
Topside and Subsea controls integration between two distinct systems
Environmental barrier and isolation assurance
The success of this endeavor is evidenced on a Flawless Start-Up and operation of the new system as an integral part of the nine-year onstream Bonga Main system. Disruption to production and impact to the existing asset were successfully minimized.
Significant insights and learning were gained in the areas of subsea communication and control interfaces, defining multiple interfaces, integrated system testing, flawless startup and sharing of information across multiple vendors.
Enhancing Air Gap Design and Assessment in Deepwater Floating System Performance
Authors: Wu Wan , Zeng Jack 
Published: April 2015

Abstract
This paper discusses how to enhance air gap design and assessment for the deepwater floating systems. The authors first establish an analytical method to predict air gap considering global upwelling due to wave diffraction, as well as random wave effects. Then the authors apply the analytical method to simulate the air gap of typical deepwater floating systems through uncoupled analysis combining frequency domain and time domain global motion analysis. For comparison, a coupled analysis with hull structure, mooring and riser system is also carried out. The authors then look into model test verification and correlation analysis of air gap prediction, especially how to deal with random motion effects on deriving the extreme values of air gap. Furthermore, the authors illustrate how to improve deepwater floating system performance and cost-effectiveness by utilizing a practical and reliable air gap design approach.
The air gap simulation results derived from the proposed analytical procedure correlate well with the wave basin model test results. This analytical procedure has also been applied to deepwater floating system design for field development projects, which can be considered as a practical and reliable air gap design solution for optimizing global configuration to improve deepwater floating system performance and cost effectiveness.
Key words: Air Gap; Floating Structure; Model Test Correlation; Random Motion
Thermal Failures in Batteries Used in Subsea Power Applications
Authors: Marr K. C. , Somandepalli V. 
Published: April 2015

Abstract
Battery packs and modules have been used extensively in industries such as consumer products, transportation and grid energy storage. Recently, interest in using large battery packs in the oil and gas industry has significantly increased. In particular, there has been an interest in developing subsea power systems, using, rechargeable batteries, for autonomous underwater vehicles (AUVs) and measurement while drilling (MWD) applications. Operating a battery with high energy density in a subsea application has several challenges–one of which is how to safely manage potential thermal failures in a harsh high pressure, high temperature environment. In this work, we outline a testing methodology for quantifying thermal hazards and overpressures associated with battery thermal failures. This work provides a framework for analyzing and quantifying thermal failure hazards for battery packs and modules that may be used in subsea power applications. Detailed characterization of the thermal failure and quantifying metrics such as maximum overpressure, rate of pressure rise, and amount of gas generated are necessary to design and implement safety features in subsea power systems to operate these batteries safely and efficiently. Properly addressing these hazards can help reduce the loss of productivity of subsea machinery and instruments, and prevent the development of life threatening conditions when large batteries are used.
Investigation and Optimization of the Effects of Geologic Parameters on the Performance of Gravity-Stable Surfactant Floods
Authors: Tavassoli Shayan , Pope Gary A. , Sepehrnoori Kamy 
Published: April 2015

AbstractA systematic simulation study of gravity-stable surfactant floods has been done to understand the conditions under which it is practical and to optimize its performance. Different optimization schemes have been introduced to minimize the effects of geologic parameters and improve the performance and the economics of surfactant floods. The simulations were carried out using horizontal wells in heterogeneous reservoirs. The results show that gravity-stable surfactant floods can be done at a reasonable velocity and with very high sweep efficiencies for reservoirs with high vertical permeability. These simulations were carried out using a three-dimensional fine grid and a third-order finite-difference method to accurately model fingering. A sensitivity study was conducted to investigate the effects of heterogeneity and well spacing. The simulations were performed using realistic surfactant properties based on laboratory experiments. The critical velocity for a stable surfactant flood is a function of the microemulsion viscosity and it turns out there is an optimum value that can be used to significantly increase the velocity and still be stable. The salinity gradient can be optimized to gradually change the microemulsion viscosity. Another alternative is to inject a low concentration polymer drive following the surfactant slug (without polymer). Polymer complicates the process and adds to its cost without a significant benefit in most gravity-stable surfactant floods, but an exception is when the reservoir is highly layered. The effect of an aquifer on gravity-stable surfactant floods was also investigated and strategies were developed for minimizing its effect on the process.
Effect of Hold Up on the Hydrate Stability Zone
Authors: Chalkidis Anastasios , Tohidi Bahman 
Published: April 2015

Abstract
Currently, reservoir fluid compositions (based on PVT reports) are used in predicting the hydrate stability zone. However, in multiphase flow there are variations in the local composition that may affect the hydrate stability zone. The main objective of this work was to investigate the effect of hold-up and the resulting variation in the local composition on the hydrate stability zone of various hydrocarbon systems.
A thermodynamic software was used to predict the composition of various phases at different locations along a pipeline. A range of liquid hold-ups were assumed and the local composition was recalculated. The hydrate option of the software was used to predict the hydrate stability zone of the resulting local fluid composition. The calculations were repeated for a number of fluid systems and the results are presented in this work.
The calculated hydrate stability zones for various hold-ups were compared with that of original reservoir fluid. The results show that hold-up plays an important role on the hydrate stability zone. High gas hold-up shifts the hydrate stability zone to the right. However, as high gas hold-ups occurs at high point and away from aqueous phase, in case of changes in the system conditions the amount of hydrates are limited to the amount of water available.
This paper demonstrates that the hydrate stability zone of a multiphase fluid in a pipeline is a function of hold-up and the resulting changes in the local composition. This could have important consequences on the hydrate prevention strategies.
Lucius Project: Export Oil and Gas Pipeline Development and Execution
Authors: Schronk L. , Biggerstaff G. , Langmaid P. , Aalders A. , Stark M. 
Published: April 2015

Abstract
This paper provides an overview of the unique challenges faced by the oil and gas export pipelines during the development and execution phases of the Lucius project. The oil pipeline will focus on the repurposing of 47 miles of the Phoenix gas pipeline for oil service which reduces infrastructure and environmental footprint in the Gulf of Mexico. The gas pipeline will focus on the re-engineering of the pipeline end terminations (PLETs) and installation procedures after the engineering and fabrication phases of the project were complete due to a change in installation vessel so that Lucius first production was not impeded.
The oil export pipeline, with a nominal capacity of 115 KBPD, is an 18-inch, 147 mile pipeline consisting of 3 segments: (1) 74 miles of 18-inch new build pipeline from the Lucius spar to the existing Phoenix pipeline, (2) test and re-use of an existing 47 mile section of Phoenix gas pipeline converted to oil service, and (3) 26 miles of 18-inch new build pipeline to the existing platform South Marsh Island 205 (SMI-205). First oil was delivered in 1Q2015.
The gas export pipeline, with a max capacity of 400+ MMCFD, is a new build 20-inch, 209 mile pipeline anchored by the Lucius and Hadrian South developments. The pipeline starts in Keathley Canyon 831 and terminates into a new build transportation platform located in South Timbalier 283 (ST-283). First gas was delivered in 1Q2015.
Top of Line Corrosion: An Evaluation of Critical Parameters that Drive Mitigation Methods and System Design in Deepwater Gas Systems
Authors: Osorio N. F. , Bukkaraju S. , Garduño J. L. , Jordan L. C. 
Published: April 2015

Abstract
Top of Line Corrosion (TOLC) occurs in deepwater wet gas systems when water vapor condenses on the upper internal walls of the flowline due to the heat exchange occurring between the hot fluid and the colder environment. The condensed liquid becomes enriched by the corrosive species naturally present in the gas stream and assumes a low pH because it does not contain any buffering species such as bicarbonate or iron. The predominant concern is carbon dioxide (CO2), which reacts with water to form carbonic acid (H2CO3), although hydrogen sulfide (H2S) and organic acids can also present significant challenges and drive the corrosion process.
Multiple factors influence the TOLC process. These include fluid characteristics and composition, flow regimes, pH, flowline material properties, fluid and ambient temperatures, protective and insulation layers properties, bathymetry and burial depth. These factors among others drive the heat transfer and consequentially impact the water condensation and the resulting TOLC rates. Adequate evaluation of the independent factors driving the TOLC risk is necessary in order to obtain an accurate assessment and mitigation option selection.
This paper aims to categorize and evaluate the impact of every key factor influencing TOLC risk and describes two methodologies available for TOLC assessment; Heuristic method, based on indirect determination of the TOLC rates, and the holistic method based on a system wide risk assessment, implemented through a System Component Analysis (SCA) approach supported by proven dynamic thermal-hydraulic and corrosion models and coupled with field experience. In addition, this paper presents the procedure to undertake effectively the TOLC risk assessment and mitigation option selection strategy based on the SCA methodology.
Numerical Simulation of Wave Loading on FPSO in Various Wave Conditions
Authors: Lubeena R , Gupta Vinay Kumar , Srinivasan Vedanth , Mohan L Srinivasa 
Published: April 2015

AbstractIn the design of Floating Production Storage and Offloading facilities (FPSO), it is important to predict the seakeeping parameters like FPSO motions. This paper focusses on the prediction of FPSO motions and wave impact loads in various irregular sea waves and proposes a Computational Fluid Dynamics (CFD) model. Accurate prediction of FPSO motions and wave impact loads requires the accurate prediction of wave kinematics. Waves generated by winds blowing over the water surface in real oceans are short-crested, so the dynamic responses of the moving structure will be very different in long crested and short-crested waves. In this paper, we have verified the pure propagation of oblique short-crested random waves in numerical wave tank with the analytical results, which serves as the basis of more complex analysis including ship hull interaction with waves.The proposed CFD model uses Multiphase Volume of Fluid Model (VOF) along with Six Degrees of Freedom Model (6DOF) to predict the hydrodynamic forces and the ship responses. Long crested and short-crested random waves are simulated in a numerical wave tank, where boundary conditions for free surface profiles and velocities are imposed at the velocity inlet boundary using Jonswap frequency spectrum and cosine-2s directional spreading function.Wave slamming loads and the structural responses depend on many factors, like sea state, FPSO speed, draft, wave heading angle, local structure etc. In this paper, we have analyzed the wave slamming on a moving FPSO for different sea states (unidirectional, multi directional with 45 deg and 90deg angular spread) and studied the resulting hydrodynamic forces and related structural interactions. Ship motions (heave, pitch and roll), vertical accelerations, pitch velocities, roll velocities and the wave impact pressures are compared among different sea states.
Process Support and Marine Systems in the Hull - Innovation Meets Regulation
Authors: Kitchen Peter 
Published: April 2015

Abstract
Historically, the marine systems on a Spar (ballasting, de-watering, ventilation, access, etc.) are relatively simple. However, attracted to the operational value of having large volumes of storage, particularly for flow assurance of the subsea wells and flowlines during shut-down conditions, the Gulfstar hull design criteria included the capabilities to store, inside the hull, 10,000 bbl of dead oil, 1,000 bbl each of diesel and methanol, all in integral carbon steel tanks, plus 2,400 bbl of subsea chemical in 18 individual stainless steel, vertical pressure vessels in both 100 and 200 bbl sizes. This took the Spar hull from being a relatively ‘unsophisticated’ hull to something much more complex.
The paper traces all the key process support and marine systems from their humble beginnings to their final form with all the Regulatory inputs and requirements which, in hindsight, turned out to be almost ‘a bridge too far.’ After a short description of the systems with unique features and the regulations and design challenges behind them, the paper focuses on recommended changes for future projects, in addition to the obvious idea of radically simplifying those systems.
As marine systems get more complex and projects try to introduce lower weight/lower cost/safer solutions ideas to optimize them, the existing Rules and Regulations can impede attempts to innovate in this area. As part of the lessons learned discussion, the paper speaks to the efficacy of risk-based design as compared to the traditional proscriptive/rules-based design approach as a way to accelerate innovation without compromising safety and operability.
The information and results presented in this paper are applicable to engineers, class societies and regulators when trying to introduce more efficient process support and marine systems.