bluuebunny/crossref_metadata_2025_split huggingface dataset:
Design Considerations of Subsea HIPPS Architectures Evaluating Functional Safety and Reliability for HPHT Application
Authors: Malave Angel , Gronstedt Jens 
Published: April 2016

Objectives/Scope: Subsea high-integrity pressure protection systems (HIPPS) have become a standard feature in numerous subsea fields around the globe. Subsea HIPPS' reduced pipeline costs are proven to shorten delivery times for pipelines by decreasing their pressure rating in green field projects or by including high-pressure wells into brownfield projects without modifying rating in existing pipelines.
New frontiers for HIPPS are created by high-pressure (7.5 to 20 kpi) and high-temperature (100° to 200°C) applications, as current pressure transmitters, valves and actuators reach their limits. Furthermore, each HIPPS challenges engineering to achieve a compromise between functional safety and reliability - especially in demanding HPHT fields. These opposing characteristics within the protection systems cannot be treated separately but have to be evaluated as two closely related aspects of engineering.
This paper covers the balancing of these two engineering areas by using the numerical evaluation of probability of failure on demand (PFD) and failure rate (FR) figures. The evaluation is based on safety integrity level 3 (SIL 3) low-demand HIPPS, for which relevant subcomponents and system failure behaviours were simulated. Different HIPPS architectures were applied based on various process sensors, logic solver and final element quantities and their arrangements. The objective of this paper is to investigate the potential improvement of HIPPS design with low PFD and high mean time to failure (MTTF).
Methods, Procedures, Process: Reliability methodologies are based on reliability block diagrams in accordance to IEC 61508 and ISO 12489. Current state of the art safety equipment generic databases for subsea equipment are used to reflect the sub-system's section of HIPPS loops with regards to their functional safety and reliability capabilities.
Results, Observations, Conclusions: This paper indicates optimal and suboptimal architectural configurations and their tradeoff regarding functional safety and reliability.
Integrated Power Management is the Key to Reliable Renewable Energy in Remote and Off-Grid Applications
Authors: O'Brien Jayne , Tomlinson James 
Published: April 2016

Abstract
Renewable energy sources, such as solar and wind, are attractive energy sources for the Oil & Gas industry, particularly in remote or off-shore applications. The challenge with these energy sources is that they cannot provide a steady, reliable source of energy on their own. To date, most systems rely on large battery banks or oversized generators to supplement the renewable power. The shortcomings include cost, size, weight and maintenance.
Tetra West Technology has conducted a series of technical studies in order to optimize the integration of renewable energy, back-up power generation, and battery storage. These design studies have resulted in development of a system which maximizes the use of the renewable energy source, minimizing the required battery capacity, and further minimizes operating time and size of the back-up generator.
Advanced integrated power management techniques can achieve 35% savings for a given solar application while assuring 99.999% power supply reliability, including remote land or off-shore locations. Integrated power management systems can be sized for a wide range of power requirements, allowing maximum benefit of renewable power – particularly when managing motor start or short term surge power requirements.
These advances in power system integration are scalable and can be applied to a wide range of applications – from small remote pumping stations to large off-shore facilities. Employing components proven for these environments, an optimized integrated power management system provides a high degree of both system and power delivery reliability. With proper system sizing, these integrated systems can assure low cost and high reliability energy in a wide range of applications.
Strength and Fatigue Assessment of Extended Bilge Keels for FPSO/FLNG
Authors: Kim Sungeun Peter , Petricic Martin , Xie Geng , Wu Guangyu , Seah Robert 
Published: April 2016

Abstract
This paper presents advanced analysis procedures for the strength and fatigue assessment of FPSO bilge keels which are developed under the joint development project (JDP) between ABS and Chevron. For enhanced performance of FPSO/FLNG units in harsh environments, large bilge keels with extended depth are often considered in real designs. Damage cases of the bilge keels have been reported, but industry guidelines on the structural design of the bilge keels are very limited due to the nonlinearity of hydrodynamic loads on the bilge keels. In this paper, a first-principles approach is proposed by introducing the Computational Fluid Dynamics (CFD) based hydrodynamic loads into the Dynamic Loading Approach (DLA) based full ship FE structural analysis for the strength and fatigue assessment of bilge keels. The design loads at a 10-8 probability level are considered for strength assessment and the long-term Weibull distributions of stress range are considered for the simplified fatigue assessment at critical locations.
Slamming Load Prediction Using Overset CFD Methods
Authors: Shen Zhirong , Hsieh Yi-Fang , Ge Zhongfu , Korpus Richard , Huan James 
Published: April 2016

Abstract
Slamming pressures provide one of the most important load sets for the design and classification of ships and offshore structures. These loads are highly localized and nonlinear, and therefore difficult to predict. Computational Fluid Dynamics (CFD) is a viable tool for their estimation, but validation must be demonstrated before its use is acceptable in standard practice. This paper addresses validation of slamming pressure predictions for two popular software packages: OpenFOAM and Star-CCM+. Both 2D and 3D tests are undertaken, and the predicted pressures compared to available validation-quality experimental data. The 2D cases involve tests of generic ship sections dropped from different heights. Three-dimensional simulations utilize a scale model 10K TEU container ship at different speeds operating over a range of incident wave conditions. The dynamic overset grid technique is applied to handle large-amplitude motions. Good agreement between CFD and experimental data is achieved in the bow area, along the bottom plating, and in the topsides flare area. A few of the comparisons (e.g. on the flat deck) highlight areas where additional work is justified. Overall, the results demonstrate the accuracy, flexibility and robustness of CFD performed using the overset grid technique.
The Development and Field Introduction of a Subsea Wellhead Connector for Intervention Operations
Authors: Canny Steven A , Foubister Graeme 
Published: April 2016

Abstract
Subsea operations in general, attract significant expense; from the requirement of a multi-disciplinary team, through to the logistics of equipment and service conveyance in a harsh offshore enviroment. Costs are typically recovered through the reservoir production potential value over a number of years – this is not the case in abandonment operations. Upon cessation of production, the cost of abandonment is absorbed as a liability; as such the focus on cost efficiency is stringent and acute. It is however an area where the adoption of new and novel technology, allied to an alternative approach to service vessel selected and campaign structure, can achieve significant cost savings.
This paper describes the development of a subsea wellhead connector intended for use in well abandonment operations, in rigless decommissioning projects conducted in the UK Continental Shelf. It presents one of alternative rigless approaches to field decommissioning, and through collaboration with operators, cost effective equipment is developed reactively to meet their operational requirements. Deviating from a Jack up/MODU based rig campaign to a Monohull based campaign has shown savings can be achieved through a significant reduction in vessel day rates and personnel costs. The requirement of rigless abandonment technologies and equipment is growing as the market adopts rigless abandonment; as such, collaboration is required to align equipment with operators requirements.
The development of the Subsea Wellhead Connector (SWC) was undertaken and delivered in 29 days, with design, application, fabrication, and commissioning expedited to meet an aggressive operations schedule. A dedicated project team allied to robust internal engineering and testing programs, facilitated the delivery and leveraged over twenty years of lessons learned in subsea operations. The SWC is intended for Intervention and well abandonment operations, including: conveyance for mechanical and abrasive cutting, wellbore communication and testing, subsea tree (XT) installation, and well barrier verification, and wellhead retrieval.
The SWC has now undertaken five campaigns in the first six months since its market entry, and displayed that collaboration and the pooling of creative talent, can provide tangible and discernible benefits to the stakeholders involved.
A Coast Guard Perspective: Evaluation of Continued Service Proposals for Floating Offshore Facilities
Authors: Phillips Tracy , Martyn David 
Published: April 2016

The views expressed herein are those of the authors and are not to be construed as official or reflecting the views of the Commandant or of the U. S. Coast Guard.
As floating offshore facilities approach the end of their design service lives, operators are working with the Coast Guard and the Bureau of Safety and Environmental Enforcement (BSEE) to gain approval for continued service. The two agencies work together to review these proposals; the Coast Guard evaluates the hull and associated safety systems, while BSEE evaluates the mooring and production systems. This paper presents a Coast Guard perspective, beginning with a review of Coast Guard structural examination records for the Gulf of Mexico. The results of this review are presented and analyzed for trends. The authors accept that a well maintained facility, with a thoroughly documented service history and inspection record, is a good candidate for life extension. This paper then discusses In Service Inspection Programs (ISIP) and Structural Integrity Management (SIM) programs, both of which provide a method of ensuring that floating offshore facilities are safely operated and maintained. These programs lay the foundation for discussions regarding continued service. This paper also discusses various information that can be used by the Coast Guard to evaluate a proposal for continued service, including, but not limited to, historical data, baseline surveys, cathodic protection, coatings, corrosion, maintenance records, inspection results, fatigue data and weight changes. While the evaluations of continued service proposals are handled on a case-by-case basis, the same basic principles apply to all floating offshore facilities which are being considered for continued service.
Challenges in Material Selection and its Qualification for use in HPHT Environment for Drilling Equipment
Authors: Meruva Satya , Patel Harish N. , Gonzalez Alexander , Cridland Marcus 
Published: April 2016

High-pressure high-temperature (HPHT) well bore conditions present a unique challenge for the equipment and materials exposed to them. The subsea environment further exacerbates the HPHT challenge due to corrosive seawater, weight restrictions, variable external loads, and lack of immediate accessibility. From a materials perspective, a comprehensive understanding of the material physical properties and robust analysis of the potential failure mechanisms active in HPHT and subsea conditions is necessary for satisfactory equipment design validation and verification. This paper will discuss the challenges in HPHT materials selection and qualification, and the process by which acceptable design practices, safety margins, and prototype testing will be established.
Environmentally assisted cracking and fatigue cracks are the dominant failure mechanisms in HPHT designs. Due to the elevated pressure and temperature, elastic-plastic material design models are applied. Dependable physical performance under extreme conditions is the primary objective. Metallic materials are generally subject to tensile tests at elevated temperatures, fracture toughness tests in simulated environments (including the drilling, production, and saltwater with corrosion protection environments). Fatigue crack growth testing is performed in order to determine the relevant material properties in anticipated environments. Elastomeric and metallic seals in HPHT design must be operable for across wide temperature range in corrosive environments and must be tested accordingly. Presently, standards specific to HPHT drilling equipment designs are still under development, and designs are evaluated from first principles due to the lack of field data. Functional production, inspection, and quality standards must also be developed. ABS is currently addressing these challenges at a design level with OEMs and is assisting in contributing to safety by verifying and validating that designs for HPHT equipment will follow the guidelines per all applicable API and ASME codes and standards. This paper will discuss the challenges associated with the material selection.
This paper aims to help to establish a baseline for on-going efforts in standardizing the certification process of HPHT materials and their manufacturing processes for global applications. The knowledge gained by the development projects will be instrumental for the classification society certifying materials for HPHT equipment, to develop certification requirements aimed at improving safety on deep-water drilling units and preventing pollution of the environment.
Lessons Learned From a Comprehensive Review of Integration and Installation Phases of Gulf of Mexico Floating Production Systems
Authors: D'Souza Richard , Basu Shiladitya , Khurana Sandeep 
Published: April 2016

Abstract
Beginning in 1986, with the Placid Oil GC 29 development using a converted drilling semisubmersible in 460 m of water, the Gulf of Mexico (GOM) has been the incubator of deepwater Floating Production System (FPS) innovation. In the following 30 years over fifty FPSs that included Tension Leg Platforms (TLPs), Spar platforms (Spars) and Semisubmersible platforms (Semisubs), were sanctioned . Deepwater frontiers have been extended to over 2,900 m in that span. Many technical and commercial challenges have been managed and overcome in doing so. In the wake of the recent collapse in oil and gas prices and the specter of a prolonged period of low hydrocarbon prices, the industry is confronting perhaps its most formidable challenge in developing new deepwater fields in the GOM that require a host facility.
Historically, all too frequent project execution cost and schedule overruns were masked by rising oil prices. In many instances, the topside to hull integration, platform installation and hook-up to mooring and riser systems and commissioning (Integration and Installation Phase) have been the root cause of overruns as they are high risk, high consequence activities with little float for schedule recovery. In the current low oil price environment there is little margin for error for Integration and Installation (I&I) miscues that rapidly erode project value.
The authors have reviewed the critical I&I phase performance of thirty-three (33) TLP, Spar and Semisub platforms in the GOM and substantiated the review based on either first-hand experience, public domain information or in discussions with project team leaderships. The objective is to provide performance benchmarks, observations and recommendations for future FPS developments in the GOM to help avoid repetition of costly missteps and delays and incorporate lessons from those projects that have been well executed.
Multiple-Point Geostatistical Lithofacies Simulation of Fluvial Sand-Rich De-Positional Environment: A Case Study from Zubair Formation/South Rumaila Oil Field
Authors: Al-Mudhafar Watheq J. 
Published: April 2016

AbstractModelling accurate geological structure is an important step in reservoir simulation. The common pixel-based algorithms are incapable of generation the most realistic geospatial patterns. However, multiple-point Facies Geostatistics (MPFG) procedure is more efficient to capture complex geological structures as it mainly based on utilizing the training images that reflect geological architecture. In this paper, we present a detailed MPFG of fluvial sand-rich depositional environment in South Rumaila Oil Field in Iraq.The fluvial depositional system was created through a 2D user-defined training image that was sampled to create a surface map. Then, neural networks algorithm was adopted to train the surface map in order to create the discrete template for pattern generation of 3D Facies distribution along with the 3D Grid Construction. The resulted training image represents a numerical geological model that contains three-dimensional information about a geological heterogeneity and structure. The facies pattern was then considered for 3D Lithofacies modelling conditioning to upscaled discrete facies distribution for 20 wells in the reservoir.Based on core data analysis, three lithofacies have been modeled and predicted for all 20 wells that were distributed main at the reservoir crest. The lithofacies are Sand, Shaly Sand, and Shale. The training image body and channels were pointed to the three aforementioned facies and it replaced the variogram to create the 3D Facies system. The resulted integrated model through multiple-point statistics has much more reasonable facies architecture than indicator simulation as it is clearly noticeable how sand channels are distributed with continuous direction towards the sea shoreface. To check how validate our model and capture the true depositional environment, many realizations were generated based on leave-one-out cross-validation technique. The sand channels continuity was achieved through spatial posterior probability of Lithofacies distribution that were incorporated in MPGF approach as 3D trend model. However, including the geometrical trend models of thickness or depth has no effect on the channels continuity. The spatial posterior probability trends were modeled from the predicted probability distributions of Lithofacies that have been created by Kernel Support Vector Machine for all 20 wells in the formation.The resulted reasonable MPGF model was considered for core permeability and log porosity distribution given each facies through Gaussian simulation. In reservoir simulation, the MPGF model has led to fast reaching the minimum error of history production matching. That reflects how is efficient considering multiple-point statistics to reconstruct complex geological structures.
Gas Hydrate Formation & Interactions for Water Continuous & Partially Dispersed Systems
Authors: Vijayamohan P. , Majid AAA , Chaudhari P. , Sloan E. D. , Sum A. K. , Dellecase E. , Volk M. , Koh C. A. 
Published: April 2016

Abstract
A major flow assurance concern is to mitigate the safety risks associated with hydrate plug formation and to provide cost effective flow assurance strategies for mature fields by extending subsea tiebacks. One major challenge for the flow assurance community is the fundamental understanding of the hydrate formation and plugging under different multiphase flow conditions. Such understanding will only lead to better hydrate management guidelines to effectively mitigate the safety risks associated with hydrates, but could also potentially reduce the operating costs by providing improved inhibitor injection strategies. The manner in which the hydrates interact/interfere with multiphase flow can be significantly different for water continuous, oil continuous, and partially dispersed systems. The latter is defined as a system containing oil/gas/water, where the water is present both as free water and partially dispersed in the oil phase (e.g., entrained water in the oil). Efforts were made to study the interaction between hydrates and multiphase flow. Controlled amounts of hydrates were formed and their effect on the pump pressure drop was studied systematically. This paper presents the experimental results and analyses of these experiments. Lessons resulting from this work could provide valuable insight with regard to the behavior of hydrates in multiphase flow, and hence could help improve operating company production strategies to mitigate the risks associated with hydrate plugs in complex multiphase systems.
Comparison of Hydraulic Power Sources for Subsea BOP's
Authors: Bedrossian Nazareth , Welker Joseph , Coppedge Charles , Hernandez Jorge 
Published: April 2016

Abstract
This paper compares the performance, nominal and robust, of hydraulic power sources that can be used to operate subsea BOPs. The comparison is made between conventional gas pressure accumulators and a dormant, on-demand power system. A brief introduction is provided to PYRO-Accumulator, developed by Bastion Technologies which uses solid propellant to pressurize hydraulic fluid in a self-contained device which is dormant until it is activated to meet hydraulic pressure demand. Simulation and field test results are used to compare the hydraulic fluid capacity needed to provide usable hydraulic fluid volume and pressure to actuate subsea BOP's.
A New Look at Seafloor Venting: Natural Gas Hydrate Derivatives
Authors: Barnard A. , Sager W. W. , Snow J. E. , Max M. D. 
Published: April 2016

AbstractNatural leaks of multiphase hydrocarbons from the seafloor are widespread. Characterizing the temporal and spatial variability of these emissions provides baselines for comparison to the magnitude of anthropogenic leaks. Determining leakage rates will be important to our understanding the sustainable implementation of subsea infrastructure and the relative contribution of natural sources to global budgets. Multibeam echo soundings from cruise AT21-02 were used to define a region with several ~600 to 900 m tall gas plumes in the water column directly above cratered hummocky regions of the sea floor with high backscatter in water depths of ~1500 m over the Barbados Accretionary Complex. The relationship of seafloor morphologic features such as faults, craters, and mud volcanoes with vent-gas plumes in the water column is indicative of substantial emissions from this region. Disappearance of the acoustic plumes at ~600 m is coincident with the top of CH4 gas hydrate stability in the water column. In the plumes, natural gas hydrate shells that form at the gas-water interface and armor the gas from dissolution during ascent likely encapsulate bubbles. Ascent-driven pressure change in the bubbles causes shattering of shells forming gas hydrate shards that rise with the ascending plume and add to its acoustic reflection strength. The multiphase fluid consisting of gas, shelled bubbles, shards, and water changes character at the top of gas hydrate stability where the hydrate dissociates and dissolves. Differentiating sources and further characterizing emissions will provide baselines and also contribute to understanding the relative importance of the different emissions sources.