bluuebunny/crossref_metadata_2025_split huggingface dataset:
Solving the Operational Challenges of Sulfate Removal Units Using High-Flux, Fouling-Resistant Nanofiltration Membranes
Authors: Krebs Thomas , Ganguli Rahul , Lage Gustavo , Verbeek Paul , Mehrotra Vivek , Florido Priscilla , Akdim Mohamed Reda 
Published: April 2019

Desulfation of seawater before injection is required to control reservoir souring and scale formation. For this task, operators use nanofiltration (NF) membranes in sulfate removal units (SRUs). The tendency of the membranes to foul is a key operational challenge. To overcome fouling, frequent chemical cleaning is required. An additional constraint for SRUs is that the amount of treated water cannot be increased easily as a higher water output results in an even faster fouling of membranes.
In this paper, we describe a method to enhance permeate flux and fouling resistance of desulfation membranes. The enhancements are achieved by modifying the active layer of commercially available NF membranes using a permanent coating that increases hydrophilicity while retaining the high surface charge characteristic of NF membranes.
We report the results of a six-month field trial with the coated membranes. The test was executed at the Seawater Desalination Test Facility in Port Hueneme, California using 2.5" dia. membrane modules. The test skid contained two different parallel flow lines with a stack of six coated 2.5" dia. membranes in series, and an uncoated 2.5" membrane for reference.
The results show a 25% higher permeate flux for the coated membranes compared to the uncoated membrane at the same transmembrane pressure. Sulfate rejection was unchanged for both coated and uncoated membranes during the entire duration of the test. The coated membrane also showed a lower fouling rate than the uncoated membrane. The time between cleaning events increased by ∼ 38 % for the coated membranes as compared to the uncoated membrane, and the coated membrane processed ∼ 63 % more permeate before cleaning was required. Preliminary results also indicate an enhanced chlorine tolerance of the coated membranes of at least 3000 ppm-h under continuous chlorination at ∼ 1 ppm.
The impact of the coating on the economics of SRU operations will be discussed in the paper. The results presented in this paper demonstrate that performance and operability of SRUs can be significantly enhanced by a newly-developed coating, and that a significant reduction in the lifecycle cost of SRUs can be achieved.
Comparison of Coupled and Decoupled Seismic Analysis of TLP Piles
Authors: Suroor Hadi , Arablouei Amir 
Published: April 2019

Abstract
Tension-leg-platforms (TLPs) are increasingly being used in offshore regions of high seismicity. The TLP foundation typically consists of very long driven piles supporting the TLP tendon loads. These piles experience significant uplift loads generated by the inherent system buoyancy. API RP 2T is considered the industry standard for TLP design which provides guidance on foundation design; however; available guidance on seismic design of TLP foundations is limited. The focus of this paper is to present and compare two types of seismic design methods for TLP piles and discuss associated outcomes, which should provide greater insight into the complexities involved in seismic design analysis.
The seismic analysis of TLP piles can be performed in two ways; coupled and decoupled analysis. In a conventional decoupled analysis, as practiced in the industry, the foundation pile is analyzed independent of the TLP structure considering various design loading conditions, including seismic loads. In the coupled analysis, the entire system including TLP structure, tendons, and piles are modeled and analyzed as one integrated system. This is done to investigate both system and component responses due to the impact of seismic ground motions. In the coupled approach, the system can be analyzed by the response spectra method for an extreme level earthquake (ELE) and the dynamic non-linear analysis for an abnormal level earthquake (ALE). The effects of seismic kinematics and inertia, soil degradation due to cyclic loading, soil damping, etc. are considered in both types of analyses.
Two case studies are presented where these methods have been applied for two TLP projects located in seismically active regions. The outcome of the study is to present a comparison between the conventional decoupled approach and the proposed coupled seismic analyses of TLP piles. This comprehensive seismic study aims to provide detailed insight into the seismic design methods of a TLP foundation to supplement the design guidance presented in API RP 2T. Although complex and time consuming, the proposed coupled approach provides greater insight into the system response.
Lean Duplex Grating Solutions to Mitigate Corrosion Problems and Weight Reduction Challenges in Offshore Platforms
Authors: Pathirana Sanj C , Claesson Peder , Kirchhartz Thomas 
Published: April 2019

Abstract
With the growing demand in cost reduction on maintenance activities as well as weight reduction solutions, it is necessary to invest in new technology and design solutions in the offshore industry.
The use of lean duplex materials has been on-going for over a decade but the application in offshore industry, specifically in new platform design and modification activities, has been quite recent. This paper gives an outlook on lean duplex material and the results of a pilot project developing a grating design which was supported by Oil & Gas Company in Norway with the aim of using lean duplex gratings in the next available modification project.
The most commonly used solution in the Norwegian offshore industry is HDG gratings. These gratings are available as ready-use cut-to-length solutions to cover the required surface area from various manufacturers.
With the mind-set of developing alternative solutions to existing grating options, selection of a superior material type with favourable characteristics such as higher corrosion resistance, mechanical properties and weldability are some of the key focus points.
At the development stage two different Lean duplex grating prototypes have been designed. The primary goal of the design was to meet all the current offshore requirements while reducing the weight on the final product. Having the option of lean duplex as the material choice for gratings provides key advantages in weight reductions and superior corrosion resistance in saline atmosphere resulting in longer lifecycle times.
The design focus on lean duplex gratings has been presently limited to the platforms, staircases and walkways, but there are a more possibilities for optimization of the design when balancing the cost / benefits of the following factors: ▪Design/Weight▪Lifetime/ Maintenance – Low Carbon Footprint▪Cost
This product development can be viewed as an incremental innovation showing the potential where a small piloting scope can have larger implications if applied in larger scale modification projects.
Integrity Management of Mooring Systems
Authors: Hageman Remco , Aalberts Pieter , Leeuwenburgh Richard , Grasso Nicola 
Published: April 2019

Abstract
Mooring systems remain an important component of an overall field development. There are numerous sources in literature describing challenges with mooring systems as well as potential solutions.
The goal of this paper is to present a number of new technologies which can be applied jointly in an integrated framework to monitor integrity of subsea mooring components. The paper will cover (1) direct tension measurements using Vibrating Wire Gauges, (2) warning systems based on anomaly detections from GPS measurements and (3) mooring line force estimation method and fatigue using time-domain simulation methods.
Vibrating Wire Gauges are a potential alternative to the use of in-line load cells or inclinometers for measuring mooring line tensions. These sensors have a proven track record in the Geotechnical Industry. A sensor dedicated for the offshore industry has been developed. The main benefit of this type of sensor is the ease of retrofitting in an offshore environment. Long-term stability tests and dynamic tests were executed and will be presented. Procedures for installation and maintenance were developed.
GPS measurements have widely been used in the industry to identify mooring failures. Post-processing methods of these measurements range from application of watch circles to Artificial Neural Networks. However, there remain important challenges with performance of these warning systems under the influence of environmental loads. The authors will show a basic concept which can overcome these limitations.
High accuracy floater position and motion measurements can be used in combination with a numerical model to determine mooring line forces in the field. This approach combines the numerical models used in the design with onboard integrity and maintenance procedures. The technical and organisational challenges of such approach are discussed. An onboard system able to capture system drift is used to update the numerical model and correct for deterioration of the mooring system over time. In-service measurements have been used to demonstrate and validate the concept. The methodology has been implemented and installed on an offshore asset which will become active in Q1 2019.
A number of industry solutions for mooring line integrity methods have been compared. All presented solutions have a role in the total mooring subsea integrity management program. Integration of these components together or supplemented with numerical analysis can be used to develop an overall mooring subsea integrity management plan and philosophy.
Erosion and Structural Integrity of Mud Pulse Telemetry Tools: Numerical Simulation and Field Studies
Authors: Mohammad Elyyan , Yuan Peng , Muhammad Sami , Zhang Hao , Huang Xu 
Published: April 2019

Abstract
Deepwater exploration and production presents some of the industry's most complex challenges, requiring huge capital investment and long-term commitment. Subsea fields face exceptional challenges during drilling, cementing, and operations. Any downtime means project delay and lost production. Consequently, it is important to have real-time data from high-fidelity measurement-while-drilling (MWD) and logging-while-drilling (LWD) tools during drilling operations.
Mud pulse telemetry is a widely used method to transmit MWD and LWD data to the surface. Availability of this real-time data is important for the economic success of the drilling operation. Consequently, it is important to maintain operational telemetry systems that provide fast and reliable data rates for downhole drilling. However, telemetry system failure due to sand erosion can be costly and cause downtime and maintenance costs to the operators. Hence, there is a constant need for accurate prediction of the location and erosion rate of these downhole systems.
In this study, we build on our earlier work, where we presented a comprehensive investigation on erosion of mud pulse telemetry tools consisting of numerical simulations and field data. In the current work, we take the numerical analysis further: we predict the location of the high erosion rates and model equipment topological changes due to sand erosion and its impact to fluid flow. The importance of this step is to capture the effect of changing geometry on the erosion rate, enabling us to estimate the reliability of the tool accurately. In addition, we investigate the structural integrity of the tool and the effect that sand erosion has on it. Structural integrity analysis of the eroded tool geometry is performed using finite element analysis (FEA). For model validation, simulation results will be compared with erosion patterns from field tests.
Assessment of Wave Energy Resources and Factors Affecting Conversion
Authors: Jones Craig , Chang Grace , Dallman Ann , Roberts Jesse , Raghukumar Kaustubha , McWilliams Sam 
Published: April 2019

Abstract
The wave energy resource for U.S. coastal regions has been estimated at approximately 1,200 TWh/yr (EPRI 2011). The magnitude is comparable to the natural gas and coal energy generation. Although the wave energy industry is relatively new from a commercial perspective, wave energy conversion (WEC) technology is developing at an increasing pace. Ramping up to commercial scale deployment of WEC arrays requires demonstration of performance that is economically competitive with other energy generation methods. The International Electrotechnical Commission has provided technical specifications for developing wave energy resource assessments and characterizations, but it is ultimately up to developers to create pathways for making a specific site competitive.
The present study uses example sites to evaluate the annual energy production using different wave energy conversion strategies and examines pathways available to make WEC deployments competitive. The wave energy resource is evaluated for sites along the U.S. coast and combinations of wave modeling and basic resource assessments determine factors affecting the cost of energy at these sites. The results of this study advance the understanding of wave resource and WEC device assessment required to evaluate commercial-scale deployments.
Structural Reinforcement and Leak Sealing with Composite Materials
Authors: Di Cesar Silva George , Georg Fink Thomas , Almeida Bordieri Pedro , Missao Watanabe Mauro , Jhoni de Oliveira Maicon 
Published: April 2019

Abstract

Objectives/Scope
This document presents the application steps of the repair and structural reinforcement system with high-performance polymer and composite material. Without the need to shut-down the offshore platform, this technology is based on ASME and ISO international standards with high safety and applicable in classified areas where hot-work permit is not obtainable.

Methods, Procedures, Process
The methods and procedures are applied and carried out exclusively for each application, after a judicious risk assessment. Recently, a 14" super duplex pipe carrying seawater line, operating at 8 bar pressure, on an oil platform located in Ghana showed active leak. In order to carry a conventional repair, (replacement of the problematic section or conventional hot welding) the shut-down of production would be necessary. Furthermore, the conventional method was not applicable due to the potentially explosive atmospheric conditions. Based on Part 4 of the ASME PCC-2 standard, the repair system was engineered to a 10-year lifespan and carried out with absolute safety. The procedure consists of a surface preparation, leak containment and structural reinforcement on the defective area of the pipe. All the steps in the aforementioned procedure were cold-work type and without the need to shut-down, therefore without loss of production. The equations used to calculate the thickness and length of the repair system with composite material, as well as the risk assessment, were in accordance to the referenced standards.

Results, Observations, Conclusions
The repair system was applied with success without the need to shut-down the production and was considered permanent by ABS. The hardness of the composite, measured after 24 hours, indicates full cure of the repair as predicted by the procedure and quality standards. Therefore, the leak was 100% sealed and the area was structurally reinforced in line with the engineering plan and without any loss of production.

Novel/Additive Information
The integrity of aging offshore assets is a common global problem due to the constraint of concurrent activities in a production environment. This methodology using composite materials in association with asset integrity management without shutdown production has gained recognition to be a long-term solution. The implementation of the repair and structural reinforcement system with high-performance polymer and composite material provides cost reduction, significant health, safety and environmental advantages as it enables immediate attention for the defect, on top of the benefit to avoid the loss of production.
Beneficial Wave Motion Response for Wind Turbine Support TLPs with Synthetic Rope Tendons
Authors: Hsu Wei-Ting , Litton Richard , Vasala Haritha , Anderson David , Sheppard Robert 
Published: April 2019

Abstract
As the offshore wind industry matures and projects begin to expand to deeper water regions, various floating systems are being considered to support wind turbines. This paper explores the feasibility of a Tension Leg Platform (TLP) support system anchored with synthetic rope tendons attached to a gravity base template to provide a platform for a wide range of water depths with acceptable operating nacelle accelerations.
In this paper, the NREL 5MW wind turbine is selected in order to provide a comparison to previous studies of steel tendon TLPs. A fully-coupled numerical modeling tool is used to assess the effects of extreme irregular sea loads on the TLP. A series of numerical simulations are carried out to compare the response of a Single Column (SC) TLP for three different water depths and three different environments. The responses are compared with the steel tendon model.
The use of synthetic rope tendons potentially offers more efficient installation options and enlarges the range of acceptable water depths. The use of a gravity base/suction pile foundation may improve the installation cost and schedule. The fully coupled nonlinear, time domain analysis tool used provides a unique look into the fully operating wind turbine under stable motion characteristics of the TLP.
Offshore Project Standardization: Harmonized Set of Standards and Specifications for Cost Reduction in Offshore Projects
Authors: Lee Hoseong Daniel , Chakala Mathew 
Published: April 2019

Abstract
Many oil majors have their own in-house safety standards, engineering and design practices. At the same time, industry groups and various local authorities have developed their own codes, standards and recommended practices. On top of this, each classification society has its own set of rules for building offshore structures and machinery.
As a result of the various requirements, highly complex specifications unique to each project are developed. The offshore project standardization effort seeks to find acceptable common ground between the numerous individual standards and requirements to reduce costs and increase efficiency in offshore engineering, procurement and construction (EPC) projects. As part of the standardization project, the specifications for the major topside equipment were developed to simplify procurement of machinery packages. In addition, bulk materials, outfitting design and the best practices for welding and inspection were standardized for construction efficiency.
A gap analysis was performed, comparing executed project specifications, industrial standards, and international and local regulations. The specifications were then harmonized focusing on construction efficiency, compatibility and operational maintenance, and with the safety requirements. A major driver in this activity was to adopt marine practices for offshore application without compromising safety and quality. Feedback on the process was obtained from an advisory group made up of owners, operators, engineering companies, vendors and shipbuilders.
Two standardization cases are presented as examples. The first is the standardization of topside piping material which resulted in the enhanced compatibility of materials and provision of greater construction flexibility, addressing material chemical composition, sour service application, wall thickness, test procedures and acceptance criteria. Secondly, a harmonized specification was developed for an air compressor package which meets the requirements for the design, inspection, testing, installation and commissioning for offshore application. The proposed standard project specifications help to reduce the potential for a manufacturer to misunderstand an owner's unique standards and requirements, and provide an opportunity to bring about cost reduction especially in unnecessary engineering and documentation.
Effect of Thermo-Physical Properties on Multiphase Flow Modeling
Authors: Erickson Dale D , Pusard Matthew Michael Farrell 
Published: April 2019

Abstract
An important, but relatively unexplored topic in multiphase flow modelling is the effect of thermos-physical properties on multiphase models. This is relevant in the context of 1-D modelling of large multiphase systems such as pipelines from subsea wellheads to the onshore processing facility. Millions are spent on multiphase flow simulation models, but not enough attention is given to the thermophysical models which can affect the results just as much as multiphase flow correlations.
A wide variety of field data have been compared to various multiphase models. More often, the multiphase flow model needs custom "Tuning" of the thermophysical properties to closely match the production data from the field. In this presentation, we discuss the impact of water content, composition of hydrocarbons, gas to oil ratio (GOR), surface tension, liquid density, and fluid enthalpy.
Typically, improving accuracy of these properties will increase the prediction of multiphase models significantly. For example, error in the temperature prediction can be reduced from 10 C to 1 C, pressure uncertainties from 25% to 5%, and liquid holdup from 30% to 10%.This presentation will present examples of each using field data, before and after this improvement. This paper will also discuss using four different equations of state (EOS) for the calculations of different properties: phase equilibrium, gas density, liquid density, and enthalpy departures. This approach is used instead of the traditional approach of using 1 cubic EOD for all properties. This talk will also present error uncertainty bands for some commercial thermodynamic simulators and their corresponding impact on the multiphase flow predictions.
Among all the properties mentioned above, surface tension needs particular attention since most of the multiphase models use it as a parameters. However, it is seldom measured for most of the hydrocarbon systems. Off-the-shelf thermodynamic simulators are not able to predict the surface tension accurately because of the variable content of naturally-existing surfactants in the hydrocarbon fluids. Hence, through this presentation, we raise the question if this is the limitation of the multiphase models for design, especially since most multiphase flow correlations have not been compared over a wide range of surface tensions.
Gas Hydrate Prospecting and Characterization
Authors: McConnell Daniel Russell 
Published: April 2019

Abstract
Data acquired from major gas hydrate field programs over the past 20 years has led to much better understanding of the distribution of gas hydrate on the continental margins and how to detect them. Gas hydrate systems are extensions of the conventional hydrocarbon system but are much more closely related to biogenic gas systems. The temperatures at which most biogenic gas is generated is mostly below the base of gas hydrate stability which means that most biogenic gas has to migrate into the gas hydrate stability zone and has to be at levels in excess of solubility for gas hydrates to form. Gas hydrates had been considered ‘self-sealing’ but evidence from pressure cores and laboratory experiments indicate that gas hydrate deposits may need local seals. Detection of gas hydrates though seismic and other remote sensing methods has been demonstrated through drilling and coring programs. The GC955 site in the Gulf of Mexico is used as an example to demonstrate exploration concepts, through basin models, seismic detection, and drilling and coring results. Data from other locations are also discussed. A review of remote sensing data that could be used to delineate and quantify gas hydrate deposits is presented with an emphasis on low frequency exploration 3D seismic for imaging gas hydrate deposits at the base of gas hydrate stability.