bluuebunny/crossref_metadata_2025 huggingface dataset:
An Autonomic SLA Monitoring Framework Managed by Trusted Third Party in the Cloud Computing
Authors: Maarouf Adil , Mifrah Youssef , Marzouk Abderrahim , Haqiq Abdelkrim
Published: March 2018

This article describes how currently, service level agreements (SLAs) assurance forms one of the major challenges for cloud computing (CC) in order to guarantee quality of service (QoS) in real-time and control SLA violations. However, due to the highly dynamic nature of this open environment, it is important to have a binding agreement between all the service parties for ensuring trust while fulfilling the expected QoS. To properly operate and manage such complex situations, an effective and efficient monitoring is crucial. The participation of a trusted third party (TTP) is necessary in order to resolve conflicts between involved parties. This article proposes an autonomic SLA monitoring framework managed by TTP composed of two modules: the first one SLA establishment module, which aims at providing support for automated SLA generation and management. The second one, a service monitoring module to dynamically monitor QoS metrics by detecting SLA violations at runtime to verify compliances for the respective SLAs, and to propose a mechanism for an adaptive remedy rectification, as a contribution at the third maturity level of the autonomic computing paradigm as defined by IBM. The framework is validated with scenarios on response time and availability, the results obtained are promising. They confirm that this framework manages SLAs in an efficient way as it detects all violations to be communicated to concerned parties, and identifies particular penalty clauses that can be used to modify the reputation of a provider over time. The TTP framework equipped with such reputation module can provide real-time assessment for consumers informed decision making to continue using a service or to migrate to another service provider in the case of service degradation. This creates a fair competitiveness between providers and hence improves service performance and the reliability in the cloud.
Mathematical Model for Information Technology Infusion for Healthcare Sector in Nigeria
Authors: Idowu Peter Adebayo , Balogun Jeremiah Ademola , Akinade Helen Olubunmi Jaiyeola , Egejuru Ngozi Chidozie
Published: March 2018

In this article, an IT infusion model was developed for the Nigerian health sector using teaching hospitals in Nigeria. The different IT technologies used by medical practitioners were identified. Structured questionnaires were used to elicit knowledge from respondents selected from teaching hospitals located in Nigeria. The results showed that the nurses and doctors with less than 5 years working experience were common users of IT. The results for the IT infusion showed that the earliest IT component in the health sector was the personal computer since the year 1994 followed by mobile phone and search engines by the year 1996 with the projector infused by the year 2001. The infusion model for the total number of users for each IT component was formulated using polynomial functions of degree, n with respect to t – the number of years after the base year of infusion of IT device. The IT infusion model developed in this paper can be used to forecast the future growth of IT within the healthcare sectors.
Advanced Mixed Heritage
Authors: Brusaporci Stefano
Published: March 2018

Aim of the article is to reflect on how digital technologies and ICT are changing the way to analyze, visualize, and communicate architectural heritage. In particular, mixed reality apps favor the constant and ubiquitous combination of reality and virtuality. A new kind of advanced heritage grows, characterized by the mix of tangible heritage and digital heritage: Reality enriches with information and virtuality acquires new potentialities with its matching with reality. This process moves from the development of digital informative models made by 3-D and database complex models, characterized by real time manipulability, navigation and interaction. This context renews people's relationship with images, allowing a sort of “visual turn” in built heritage field, where reality reaffirms its centrality, and the digital sphere opens to new opportunities in architectural heritage's studying, computing, experiencing, and valorization. Follows a claim for transparency of information and computer-based visualization.
ArchaeoGRID Science Gateways for Easy Access to Distributed Computing Infrastructure for Large Data Storage and Analysis in Archaeology and History
Authors: Pelfer Giuliano
Published: March 2018

This article describes how archaeological and historical research grew as a multidisciplinary and interdisciplinary activity due to availability of larger amount of data within the reconstruction of global historical and archaeological contexts at a global spatio-temporal scale. The increased information, also integrated with data from the Earth Sciences, has had an effect on the exponential increase of complex sets of data and of refined methods of analysis. For such purposes, this article discusses the ArchaeoGRID Science Gateway paradigm for accessing ArchaeoGRID Cyberinfrastructure (CI), a Distributed Computing Infrastructure (DCI), that can supply storage and computing resources for managing and analyzing large amount of archaeological and historical data. In fact, ArchaeoGRID Science Gateway is emerging as high-level web environment that makes easier the access, in a transparent way, to DCI, as local high-performance computing, Grids and Clouds, from no specialized Virtual Research Communities (VRC) of archaeologists and historians.
A Novel Hybrid Algorithm Based on Firefly Algorithm and Differential Evolution for Job Scheduling in Computational Grid
Authors: Ghosh Tarun Kumar , Das Sanjoy
Published: March 2018

Scheduling jobs in computational Grids is considered as NP-complete problem owing to the heterogeneity of shared resources. The resources belong to many distributed administrative domains that enforce various management policies. Therefore, the use of meta-heuristics are more appropriate option in obtaining optimal results. In this article, a novel hybrid population-based global optimization algorithm, called the Hybrid Firefly Algorithm and the Differential Evolution (HFA-DE), is proposed by combining the merits of both the Firefly Algorithm and Differential Evolution. The Firefly Algorithm and the Differential Evolution are executed in parallel to support information sharing amongst the population and thus enhance searching efficiency. The proposed HFA-DE algorithm reduces the schedule makespan, processing cost, and improves resource utilization. The HFA-DE is compared with the standard Firefly Algorithm, the Differential Evolution and the Particle Swarm Optimization algorithms on all these parameters. The comparison results exhibit that the proposed algorithm outperforms the other three algorithms.
A Highly Efficient Big Data Mining Algorithm Based on Stock Market
Authors: Yang Jinfei , Li Jiajia , Xu Qingzhen
Published: March 2018

This article proposes a new algorithm which includes two stages. First, the Pearson correlation coefficient is used to calculate the similarity data, and the activity of stock money flow was calculated by combined the probability generating function (P.G.F.) of stationary waiting time and stationary queue length. Second, the discrete time Geo/G/1 queue with a Bernoulli gated service is proposed in calculating money flow by data mining of stock. The new algorithm could calculate data in real time, and each investor could see the real-time data mining graphics. Investors could establish their quantitative trading strategies based on the new money flow model. The proposed algorithm exploits the nature behind stock data. The experimental results show that the authors' approach can be automatically implemented by the investment strategy and know the future trend of the stock market, as well as the economic development of the region, according to the results of the stock data mining in a certain region.
An Efficient Geometric Method for 3D Reconstruction Based on Images
Authors: Zhu Ying , Jiang Jingyue , Tang Zhiling , Wang Fang , Wang Rong , Zhong Si , Luo Xiaonan
Published: March 2018

In this article, a new geometric method for 3D reconstruction based on images is presented. The main advantage of this method is low data storage requirement and high computation process efficiency. The key mathematical methods are curve and surface modeling technology. In order to implement geometric method for 3D reconstruction, a new surface is developed named as rational W-spline surface via tensor product, through the important properties of the basis function, the authors get the important properties of the rational surface. By giving the new control matrix and the change of the parameters based on the images, 3D reconstruction effect can be obtained. This surface includes non-rational surface and rational surface, and their tensor product forms are adopted. In order to express this algorithm intuitively, the bilinear W-spline surface is realized by the experiment. The experimental results showed that the geometric method can be used to the 3D reconstruction.
Spam Detection on Social Media Using Semantic Convolutional Neural Network
Authors: Jain Gauri , Sharma Manisha , Agarwal Basant
Published: March 2018

This article describes how spam detection in the social media text is becoming increasing important because of the exponential increase in the spam volume over the network. It is challenging, especially in case of text within the limited number of characters. Effective spam detection requires more number of efficient features to be learned. In the current article, the use of a deep learning technology known as a convolutional neural network (CNN) is proposed for spam detection with an added semantic layer on the top of it. The resultant model is known as a semantic convolutional neural network (SCNN). A semantic layer is composed of training the random word vectors with the help of Word2vec to get the semantically enriched word embedding. WordNet and ConceptNet are used to find the word similar to a given word, in case it is missing in the word2vec. The architecture is evaluated on two corpora: SMS Spam dataset (UCI repository) and Twitter dataset (Tweets scrapped from public live tweets). The authors' approach outperforms the-state-of-the-art results with 98.65% accuracy on SMS spam dataset and 94.40% accuracy on Twitter dataset.
Proficient Normalised Fuzzy K-Means With Initial Centroids Methodology
Authors: Virmani Deepali , Jain Nikita , Parikh Ketan , Upadhyaya Shefali , Srivastav Abhishek
Published: March 2018

This article describes how data is relevant and if it can be organized, linked with other data and grouped into a cluster. Clustering is the process of organizing a given set of objects into a set of disjoint groups called clusters. There are a number of clustering algorithms like k-means, k-medoids, normalized k-means, etc. So, the focus remains on efficiency and accuracy of algorithms. The focus is also on the time it takes for clustering and reducing overlapping between clusters. K-means is one of the simplest unsupervised learning algorithms that solves the well-known clustering problem. The k-means algorithm partitions data into K clusters and the centroids are randomly chosen resulting numeric values prohibits it from being used to cluster real world data containing categorical values. Poor selection of initial centroids can result in poor clustering. This article deals with a proposed algorithm which is a variant of k-means with some modifications resulting in better clustering, reduced overlapping and lesser time required for clustering by selecting initial centres in k-means and normalizing the data.
Stroke Rehabilitation and Parkinson's Disease Tremor Reduction Using BCIs Combined With FES
Authors: Adama Sophie V. , Bogdan Martin
Published: March 2018

This article describes how Stroke and Parkinson's disease are two illnesses that particularly affect motor functions. With the advancements in technology, there is a lot of research focusing on finding solutions: to contribute to neuroplasticity in the first case, and to reduce symptoms in the second case. This manuscript describes the design of a brain-computer interface system (BCI) system paired with an electrical muscle stimulation suit for stroke rehabilitation and the reduction of tremors caused by Parkinson's disease. The idea is to strengthen the sensory-motor feedback loop, which will allow a more stabilized control of the affected extremities by taking into account the patient's motivation. To do so, his brain signals are measured to detect his intention to attempt to execute a movement, in contrast to the classical approach where the movement executions are imposed. A first feasibility study was completed. The author's next step is planning to test the system first with healthy subjects and finally with patients.
Discrete Time Sliding Mode Control Scheme for Nonlinear Systems With Bounded Uncertainties
Authors: Ghabi Jalel , Rhif Ahmed , Vaidyanathan Sundarapandian
Published: March 2018

This article introduces a sliding mode controller to stabilize a discrete-time nonlinear system in the presence of uncertainties and external disturbances. The proposed controller is derived to guarantee the existence of a quasi-sliding mode, taking into account the upper bound of uncertainties. With this method, a recursive switching function is used, which allows for recovering lost invariance and robustness properties of a discrete sliding mode control. As for the system stability, it is found that the system is stabilized and finally restricted to a known region. This control scheme ensures robustness against parametric uncertainties and external disturbances as well as the elimination of chattering. In this article, after a detailed formalization of the proposed control design, a numerical example for an inverted pendulum is considered, proving the effectiveness of the control methodology.
E-Waste Recycling System in Closed Loop Supply Chain
Authors: Nikabadi Mohsen Shafiei , Hajihoseinali Amin
Published: March 2018

This article describes how technology growth and the lifecycle of devices and also other tendencies for buying new devices all cause a huge mass of electronic waste. Due to materials used in production which are dangerous or valuable metals, the environmental aspects and natural resources make electronic waste management and electronic waste recycling a pressing subject. This article studies electronic waste recycling and its importance in research of closed loop supply chain management and the impact of electronic waste recycling. Using structural equation modelling to study the factors, data was collected from 120 expert questionnaires and analyzed by SPSS and SmartPLS. Causal relationships among the studied factors and efficacy coefficients of each factor were identified by the fuzzy DEMATEL technique. Finally, the dynamic model was plotted by VENSIM.
The Bottled Water Market and Consumer Behavior
Authors: Pllana Mustafe , Qosa Arbenita
Published: March 2018

This article describes how packaged water consumption has risen sharply in the world over the past 30 years. It is the most dynamic sector of the food and drink industry. The growth of bottled water sales is the contribution of the marketing activities, promotion, and aggressive sales. Is there a difference between bottled water and tap water? Opinions are divided. Some are for bottled water, some for tap water. World consumption of bottled water in 2013 was 70,371.6 million gallons or more than consumption in 2008 for 6.2%. Kosovo is a small country with a small purchasing power. In recent years, Kosovo has increased the use of packaged water by the population, due to a lack of viable drinking water running to the water network, and also as a result of social changes and the mentality of people. This article will deal with Kosovo's market developments, consumer behavior and factors that affect the behavior of purchases.
Study on the Evolution of the Meat Price Following the Russian Embargo
Authors: Petre Ionut  Laurentiu
Published: March 2018

This article assesses how and the extent to which EU meat prices are influenced by Russia's embargo. The first part assesses the meat market in the European Union, so it will analyse data on livestock, production and average prices. In the second part, the analysis is reflected on the Russian Federation in order to determine the relationship between consumption and production, then between demand and supply. Using trade data between the two regions, the level of Russian meat import reduction is set. At the end of the article, the link between the average price of meat and the value of Russian imports taken from the European Union is analysed.
Persuasive-Pervasive Technology
Authors: Tham Jason
Published: March 2018

This article positions wearables advertising within the realm of rhetoric and presents an analysis of rhetorical strategies employed by commercials that represent four wearable devices, namely Google Glass, Fitbit Charge, Apple Watch, and Microsoft HoloLens. Through a methodological framework built around visual analysis and visual rhetoric, the author presents a set of approaches that elucidate the specific rhetorical strategies of euphoria, empowerment, and enrichment of experience, which leads to a pervasive-persuasive construct of information centrism. The author then discusses the implications of such construct for the ideology of technology, particularly in industrial and pedagogical settings.
Evaluation of Gas Productivity from Layered Heterogeneity Methane Hydrate Reservoirs by Depressurisation
Authors: Yuan Yilong , Xu Tianfu , Xia Yingli , Xin Xin
Published: March 2018

Marine gas hydrate drilling explorations at the Eastern Nankai Trough of Japan revealed the variable distribution of hydrate reservoirs, which are composed of alternating beds of sand, silt, and clay in sediments, with vertically varying porosity, permeability, and hydrate saturation. The main purpose of this work is to evaluate gas productivity from the layered methane hydrate reservoir by depressurization through a conventional vertical well, and to investigate the effects of reservoir heterogeneity on production performance. We first established a history matching model by incorporating the available geological data at the offshore production test site in the Eastern Nankai Trough. The reservoir model was validated by matching the fluid flow rates at production well and temperature changes at monitoring well during field test. The modeling results indicate that the hydrate dissociation zone is strongly affected by the reservoir heterogeneity and shows a unique dissociation front. Gas production rate is expected to increase with time and reaches the considerable value of 3.6 × 104 ST m3/d, owing to the significant expansion of the dissociation zone. The cumulative volume of gas produced at well is 1.18 × 107 ST m3 over one-year period. The homogeneous reservoir with uniform value of permeability and hydrate saturation leads to significant underestimation of gas productivity when compared with the layered hydrate reservoir.
The Operational Benefits of 30-in. Casing While Drilling CwD Conductor Installation
Authors: Roy C. H. , Frederick A. T. , Thibodeaux J. J.
Published: March 2018

The paper reports a best-practices case study regarding the Casing-while-Drilling (CwD) installation of large outer-diameter (OD) tubulars—30-inch casing, specifically—in a troublesome zone in Campeche Bay, Mexico. The 30-in. CwD job was an industry first for this pipe size. The installation was an ambitious attempt to drill a 30-in. conductor in an area historically fraught with extreme wellbore instability and to produce better results than conventional drilling could deliver.

Another objective was to push the 30-in. conductor to a depth that had been unattainable in previous instances of comparable lithology. Hammering was too disruptive for such a precarious formation, and conventional drilling, with its manual equipment and serial tripping, was too time-consuming, making well collapse probable. CwD, therefore, was the best option.

The CwD process entailed a 30-in. Casing Running Tool (CRT) with hydraulic pick-up arms and a remotely operated Single Joint Elevator (SJE) handling the casing, the first joint bearing a 34-in. drillbit. In one run, the 30 × 34-in. conductor section was drilled, cased, and cemented at a total depth of 256m—78m reaching/jetting into seabed, 178m drilling. The job only took 9.52h, with an average Rate of Penetration (ROP) of 18.04m/h, and drill-time was reduced by 1.31d (26.3%) when compared to conventional drilling. And there were no stuck pipe issues, problems while tripping in the hole, or safety incidents.

Successful completion of the well hinged on the CRT's multi-functionality and capacity for running large-OD tubulars. Filling, or pumping, the string while lowering served as a lubricator, evacuating cuttings more effectively and resolving the hole-cleaning inefficiencies experienced in adjacent wells. The improved running efficiencies were also realized due to the hydraulic arms enabling better control of pipe movement; more specifically, the operational benefits of superior handling of large-OD pipe were three-fold.

First, rotation of the string enhanced the plaster/smear effect, strengthening the wellbore, averting lost circulation, and minimizing formation damage. Second, the large casing-to-wellbore diameter ratio created a gauged well, the smoother, more circular profile contributing to better well stability and requiring less cement. Third, a small, mono-bore annulus (between wellbore and casing) and consequent higher annular velocity facilitated cutting transport, prevented wellbore erosion, and resulted in hydraulic optimization while running 256m of conductor.
The Dependence of Methane Foam Transport on Rock Permeabilities and Foam Simulation on Fluid Diversion in Heterogeneous Model Reservoir
Authors: Zeng Y. , Bahrim R. Z. Kamarul , Bonnieu S. Vincent , Groenenboom J. , Shafian S. R. Mohd , Manap A. A. Abdul , Tewari R. D. , Biswal S. L.
Published: March 2018

This paper investigates the effect of rock permeability on foam transport in porous media both at the core-level and at the field level for enhanced oil recovery (EOR) applications. Foam offers promise to simultaneously address the issues that limit the overall oil recovery efficiency of water-alternating-gas (WAG) process such as viscous fingering, gravity override, and reservoir heterogeneity. However, in the literature, limited foam data were reported using actual reservoir cores at harsh conditions. In this paper, a series of methane (CH4) foam flooding experiments were conducted in 3 different actual cores from a proprietary reservoir at elevated temperature. It is found that foam strength is significantly correlated with rock permeability. We calculated the apparent viscosity based on the measured pressure drop along the core samples at steady state. The calculated apparent viscosity was found to be selectively higher in cores of high permeabilities compared to that in cores of low permeabilities. We parameterized our foam system using a texture-implicit-local-equilibrium model to understand the dependence of foam parameters on rock permeability. In addition, we established a 2-layered heterogeneous model reservoir in the Shell in-house simulator called MoReS (Modular Reservoir Simulator) to systematically study and compare the driving forces for fluid diversion during foam flooding at the field level including the gravitational force, the viscous force, and the capillary force. During the WAG process, gravitational force kept the gas from sweeping the lower part of the reservoir. The gravity can be overcome by viscosifying the gas with surfactant solution. In addition, capillary pressure which hinders the gas from entering the low permeability region can actually redistribute the two phases during foam EOR and improves the sweep efficiency. It is concluded that foam can effectively improve the conformance of the WAG EOR in the presence of reservoir heterogeneity.
Impact of Injection Scenario on CO2 Leakage and CO2 Trapping Capacity in Homogeneous Reservoirs
Authors: Al-Khdheeawi Emad A. , Vialle Stephanie , Barifcani Ahmed , Sarmadivaleh Mohammad , Iglauer Stefan
Published: March 2018

The impact of different injection scenarios on the vertical CO2 leakage and on the capacity of CO2 storage in homogeneous reservoirs has been systematically investigated by comparing the total vertical CO2 plume migration distance, the amount of free CO2 and the capacities of capillary and solubility trapping obtained. A 3D homogeneous reservoir simulation model has been developed to simulate a CO2 plume behavior for three different injection scenarios (water alternating CO2 (WACO2) injection, periodic injection and standard continuous CO2 injection). The injection period was 20 years and the total amount of injected CO2 was 20 Mton, for all injection scenarios. Then, after the end of the injection period, a storage period of 200 years was simulated. We then compared the CO2 leakage and the amount of free, dissolved and trapped CO2 between these three injection scenarios. The results show that, after 200 years CO2 storage period, injection scenario significantly affects the vertical CO2 leakage and the CO2 trapping capacities in homogeneous reservoirs. Firstly, our results show that the standard continuous CO2 injection and periodic injection scenarios lead to increase the CO2 mobility and vertical CO2 leakage. In addition, the simulation results show that the amount of CO2 trapped (by both residual and solubility trapping) in the standard continuous CO2 injection scenario is less than that trapped in the other injection scenarios. Thus, we conclude that injection scenario has an important effect on the CO2 sequestration processes.
Rapidly Rig Installable and Re-Usable Suction Bucket Wellhead Platforms
Authors: Deeks Andrew , Gaunt Peter , Torgersrud Øyvind , Boylan Noel , O'Leary Darren , Field David
Published: March 2018

A combined offshore jacket structure and foundation concept is presented, which is installable from a jack-up drilling rig. This novel system integrates the various components with extensive track record in both the offshore oil & gas and windfarm industries. It is founded on suction buckets that use water underpressure to drive installation of the foundation. It is rapid and quiet to install and re-usable; utilising the same jack-up that will be drilling and/ or abandoning the wells to perform the installation/relocation. The scope of the paper is to present the technical aspects of installation, structural and foundation engineering necessary for successful development of such facilities. This includes consideration of interaction between the structure and jack-up during both installation, but also during operation (work-over) and re-use.
Well Design for Methane Hydrate Production: Developing a Low-Cost Production Well for Offshore Japan
Authors: Yamamoto Marcio , Miura Kazuo , Wada Ryota , Takagi Ken
Published: March 2018

The key word for the production development of offshore methane hydrate reserves is "Low-cost". In this article, we propose the design of a subsea production well that could be deployed at the Nankai Trough, offshore Japan. Instead the traditional drillship, we intend to use a combination of three specialized vessels: (i) top-hole drilling vessel, (ii) well intervention vessel equipped with Coiled Tubing Unit and (iii) subsea equipment support vessel. These three specialized vessels have cheaper daily rates than a single last generation drillship. Keeping the limitations of such vessels in mind, we propose a well with a top-hole composed only by the surface casing. Further, we intend to use the "coiled tubing drilling" technology to drill-in, what shall reduce the operational time. Then a liner could be used as interface with the reservoir. In terms of completion, the methane shall be produced by the annular and a tubing shall be installed to remove the water from the well bore using a pump that is installed outside the well. Such arrangement makes the installation and maintenance of the pump easier because the equipment can be replaced without the need of a heavy workover.

Summarizing, the use of specialized vessel in distinct phases of the well construction may reduce the cost in 2 ways: cheaper daily rates than a traditional drilling and reduced operational time due to specialization itself (reduced time for rig up/down of equipment for distinct phases). Further, the use of coiled tubing and a simple completion shall reduce the operational time and equipment costs.
Innovative Noise Analysis Modeling Scheme Produces Results in Half the Time of the Traditional Method
Authors: Zhu Ruiyi , Wooi Theam KoK , Xu Dong , Wu Jer-Fang
Published: March 2018

Because noise issues onboard marine and offshore structures can adversely affect the performance and health of crew members, the subject has gained increasing attention in recent years. Noise analysis is necessary to improve acoustic design and mitigate inappropriate noise.

The innovative modeling scheme for noise analysis presented in this paper focuses on simplifying the noise modeling method. Case studies were conducted for an anchor handling tug supply (AHTS) vessel (Nam Cheong Limited 1st design project NCA80E – 64.8m 80t AHTS DE) and an 80,000 deadweight long-range product tanker to demonstrate the simplified modeling method. Noise analysis results were compared with the measurement data to validate the proposed method.

Two models – including the whole vessel model and the simplified model, comprising only part of the vessel encompassing the accommodation block and engine room area – were analyzed under transit conditions using the statistical energy analysis (SEA) software Designer Noise. The analysis accounted for multiple noise paths from major noise and vibration sources, including airborne path, first structure-borne path, and secondary structure-borne path. The primary structures, compartments of interest, and outfitting were modeled to calculate the sound attenuation from the sources to the receiver rooms.

Differences in the case study analysis results, calculated using the entire vessel model and the simplified model, are 0.03 dB for the AHTS and 0.17 dB for the tanker, which is negligible. Moreover, the analysis results of the simplified model are all higher than those of the entire model, which indicates that the simplified method is slightly on the conservative side. By comparing the analysis results of the simplified model with the actual measured noise levels of the AHTS for a total of 35 sites, it is found that 51.4% of the sites are within 3 dB, and 28.6% of the sites are within 3-5 dB, while only 20 % of the sites are larger than 5 dB. By comparing the analysis results of the simplified model with the actual measured noise levels of the tanker for a total of 48 sites, it is found that 60.4 % of the sites are within 3 dB, and 29.2% of the sites are within 3-5 dB, while only 10.4 % of the sites are larger than 5 dB.

The proposed method can reduce the modeling time of the main hull by approximately 50% while still maintaining comparable accuracy.
CO2 Direct Utilization Technology for Economic Development of High CO2 Gas Field: A Technology Assessment Study
Authors: Lahuri H Mumtaz , Seman Akbar A , Berahim N Hafizah , Onn M Syazwan , Nor M Ghaddaffi M
Published: March 2018

Permanent abatement of CO2 has become a major challenge in many gas field developments especially within this South –East Asia region. Among the challenges are on how to dispose or utilize this huge amount anthropogenic CO2 safely and economically. Therefore, the objective of this study is to identify the best technology for non-catalytic CO2 Direct utilization to manage and support economic development of high CO2 gas field in Malaysia. A Market survey was conducted to a few shortlisted technologies to assess on the technology landscape and the market potential. The feedback was analyzed based on the criteria established on the basis of company requirement. From the study, ‘Mineral Carbonation’ has been identified as one of the potential technology solution for permanent sequestration of CO2 in Malaysia. The future of this technology application is very promising due to the availability of the local feedstock, mineral waste and the potential market of this product especially for carbonate product such as precipitated calcium carbonate (PCC). However, this technology still possesses some technical challenges due to slow kinetic reaction. For a large scale application, this will become more demanding especially in terms of footprint as the current technology is mainly on batch process. Therefore, the current R&D should look into area where this process kinetic can be improved and to look into continuous or semi-continuous process for smaller footprint.
Development of Technologies of Floating LNG Bunkering Terminal and Assessment of Safety and Performance
Authors: Kim Y. , Cho S. , Jung D. , Sung H. , Hong J. , Jung S.
Published: March 2018

The concept of Floating LNG Bunkering Terminal (FLBT) has been developed for offshore bunkering services in Korea. FLBT which has a 220k m3 storage capacity is under developing, which can receive LNG from LNG carriers or transfer LNG to LNG bunkering shuttles at sea. FLBT is consisted of the hull, the mooring system and equipments including the berthing system, the ship-to-ship transfer system. As the safe LNG transfer operation is the most essential point for this facility, a series of experiments was performed in order to verify the operational safety of LNG loading and unloading operations at ocean environment.

The preliminary design includes FLBT hull design, operational site, requirements, side-by-side and turret mooring system, and LNG transfer process. Experiments of ship-to-ship mooring configurations were performed in the ocean engineering basin of Korea Research Institute of Ships and Ocean engineering(KRISO). Experimental results were reviewed with aspect to motion responses of floaters, tensions at the ship-to-ship mooring system, and relative motions between LNG loading arms and corresponding manifolds.

In the experiments, the loads on the ship-to-ship mooring system did not exceed their maximum breaking loads, while motion responses of bunkering shuttles were relatively large. The experimental results will be also analyzed in terms of the reliability of ship-to-ship mooring lines and the applicability of a conventional rigid LNG loading arm. Finally, the design will be updated continuously with the conceptual development of FLBT and the feedback from the stability check.
Applications of Hydrocarbon Prediction in Malaysian Offshore Using a New Attribute in Place of Conventional AVO Fluid Factor
Authors: Changcheng Liu , Ishikura Kazuki , Hermana Maman , Sum Chow Weng , Ghosh Deva Prasad
Published: March 2018

Seismic interpretation is one of key steps in the hydrocarbon predication. However, amplitude interpretation using post-stack data is ambiguous because P-wave, S-wave velocity and density can be given by different rock case. A high-porosity brine-filled rock can produce a response same as a mid-low-porosity and hydrocarbon-filled rock as shown in Figure 1.
Challenges and Opportunities of Gas Hydrate Production in China
Authors: Lau Hon Chung , Zhang Ming , Wang Jinjie , Pan Lin
Published: March 2018

Gas hydrate has been found both in the permafrost and deep ocean in China. However, due to easier access, much lower well cost and proximity to existing gas pipelines, gas hydrate in the permafrost is more attractive for commercial development. In this paper we examine the published data on gas hydrate exploration in various Chinese permafrosts, identify the key technical challenges and suggest directions for future study.

Our study has identified Qilian Mountain Permafrost, Mohe Basin and Qinghai-Tibetan Plateau as the three permafrosts with highest potential for gas hydrate development. Of the three, only Qilian has confirmed occurrence of gas hydrate by coring. From the perspective of field operations, Qilian ranks highest in potential for development due to its proven hydrate occurrence, thickness of hydrate bearing layer and proximity to existing gas pipelines. Mohe ranks second due to its benign operating conditions. However, it lacks existing gas pipelines. Qinghai-Tibetan Plateau ranks third due to its high elevation which limits access and lack of oilfield infrastructure.

We found that the key subsurface uncertainty is the gas hydrate saturation. There is little information on it for all three permafrosts. Other subsurface uncertainties include the thickness of the permafrost, geothermal gradient beneath the permafrost, porosity, gas hydrate composition and permeability of the hydrate-bearing layer. Future research needs to determine these reservoir properties accurately.

Examination of core samples and logs from Qilian shows that gas hydrate distribution is discontinuous both vertically and areally. Therefore, a better way to quantify the uneven hydrate distribution in the reservoir is needed for reservoir engineering calculations.

Current estimates of well production rate by reservoir simulation are sub-commerical and probably due to the assumption of pure methane hydrate which limits the thickness of the gas hydrate stability zone. Also, the assumption of using horizontal wells for hydrate production may be optimistic due to shallow depths and the discontinuous nature of hydrate distribution. Consequently, new recovery methods besides depressurization and thermal stimulation will be needed to increase the well production rate.

Furthermore, we have identified a number of similarities in production engineering aspects of gas production from hydrate and coalbed methane (CBM) wells. Common challenges include reservoir depressurization by water production, solids production, need for artificial lift and difficulty in drilling long horizontal wells in shallow reservoirs. Therefore, some best practices from CBM production, such as pad drilling, artificial lift and water treatment methods, may be usable for gas hydrate production.
Hydrodynamic Interactions of Tank and Barge System for Modular Floating Oil Storage Tank Facility
Authors: Wan Ling , Magee Allan Ross , Zhang Chi , Jin Jingzhe , Han Mengmeng , Ang Kok Keng , Hellan Øyvind
Published: March 2018

A modular floating concept for oil storage is proposed. The concept, which is advantageous for space-constrained locations, is composed of several modular floating tanks and barges. The floating multi-body hydrodynamic interaction of barges are studied in this paper. In the analysis, a single barge and then two-barge system are firstly analyzed to investigate the hydrodynamic interaction effect. More bodies are involved in the subsequent investigation. This study provides physical principles for different basic scenarios, and practical insights into how the hydrodynamic interaction problem affect the multi-body floating system.
Investigation into the Performance and Safety of Alternative Refrigerants to Ammonia for Integrated OTEC Application
Authors: Lee C. J. , Lim F. H. , Lim J. A. , Osman Shariffah Mastura Noor , Hamid Nurul Shakira , MdNor MohdAdzwan
Published: March 2018

Ocean Thermal Energy Conversion (OTEC) has garnered international interest as a clean and sustainable source of secondary power generation, without impacting the environment and regardless of seasonal weather conditions, for offshore Oil & Gas (O&G) processing facilities. This is considering the suitability of waste heat extraction from existing offshore deepwater Oil & Gas platforms as a complementary application for integrated OTEC modules (hereafter abbreviated as i-OTEC). Such an application is possible with the availability of cold seawater drawn from extended seawater lift caissons or deepwater intake risers. This study investigates, in detail, the various refrigerants that are feasible alternatives to Ammonia (NH3) for a 1MWe i-OTEC scheme.

Anhydrous NH3 or R717 was initially selected as the refrigerant for the aforementioned i-OTEC scheme which is modelled based on an Organic Rankine Cycle (ORC). It is widely accepted that R717 is the ideal refrigerant for this application due to R717's high enthalpy change during expansion. Although R717 is classified toxic, R717 emissions generally do not create environmental problems, and is detrimental to health only upon presence of R717 at a Short Term Exposure Limit (STEL) of 35ppm. For comparison purposes, other alternative refrigerants were also studied; focusing particularly the risks associated with the refrigerants including toxicity, flammability, asphyxiation, reactivity and physical hazards. Hence, the selection of the refrigerant was a major factor in the design as it provides the basis for further investigation. Shortlisted alternatives, which include R1234yf, R410a, R134a, R290 and R32, were additionally assessed on multiple factors including expected enthalpy gain from the Rankine cycle, circulation flowrate, equipment sizing, hazard classification of refrigerants, compliance to international/local exposure standards, handling and storage of refrigerants.

It is identified that the aforementioned refrigerants are possible alternatives to R717 - but with some drawbacks from a thermodynamic performance perspective, and the fact that some of these refrigerants would be rendered obsolete in various industries. Consideration of the next generation of refrigerants must balance out factors such as public awareness, manufacturers availability, safety aspects and environmental concerns. The latest refrigerant with minimal environmental impact is R1234yf and it has been slowly accepted in the HVAC and motor industry.

Additionally, the turboexpander-generator shaft sealing was identified as the major source of refrigerant emissions during normal operation. Hence, various shaft sealing solutions were also scrutinized to assess the viability of utilizing R717 as a refrigerant whilst still fulfilling safety and emission requirements.
Enhanced Gas Recovery from Water Saturated Hydrate Bearing Sediments Using Horizontal Wellbore
Authors: Rong Chong Zheng , Yin Zhenyuan , Cheong Khoo Boo , Linga Praveen
Published: March 2018

Natural gas hydrate is regarded as a potential energy resource in the future. Although it is well known that hydrate dissociation produces both gas and water, it is still unclear how gas and water are produced from hydrate bearing sediment in response to different production strategies. While a large body of literature have focused on elucidating the effect of production conditions (e.g. pressure, temperature) on the dissociation behaviour from hydrate reservoirs, limited effort has been paid in investigating how gas and water production can be simultaneously controlled through process design (e.g. the incorporation of wellbore, wellbore design).

In this study, the effect of a single horizontal wellbore on gas and water production from water saturated hydrate bearing sediments of 40% hydrate saturation (SH) was evaluated by a comparison with the base case (without wellbore) in a 980 mL crystallizer at a bottom hole pressure (BHP) of 3.5 MPa. Distinctive production behaviour, in terms of temperature, gas and water production kinetics, was observed in each production configuration. We have demonstrated an improvement of ~ 15% in gas production through the addition of horizontal wellbore in the current system. Even more so, water production was found to be reduced significantly (~ 50%) through the incorporation of horizontal wellbore. This finding revealed opportunities in future research to develop technology that enable simultaneouos enhancement of gas production and mitigation of water production during hydrate recovery.
Effect of Polyethylene Glycol Aqueous Solution on Methane Production from an Artificial Hydrate Reservoir
Authors: Mech Deepjyoti , Nair Vishnu Chandrasekharan , Kumar Ganesh , Sangwai Jitendra S
Published: March 2018

Natural gas hydrates have gained a huge attention as a potential future energy source. Reserches and pilot operations on methane recovery from hydrate reservoirs are going on worldwide. In the present work, an artificial hydrate reservoir has been developed in lab scale using silica sand of 0.16 mm particle size, distilled water and methane gas inside a high-pressure reactor. The effectiveness of polyethylene glycol (PEG) as an inhibitor for the dissociation of natural gas hydrate has been investigated. A porous sand bed of 70% water saturation has been prepared inside a high-pressure reactor and then charged with methane gas at 8 MPa. After the hydrate formation in the porous bed, for dissociation of the hydrate reservoir, PEG aqueous solution has been injected into the hydrate reservoir using a syringe pump. The pressure of the reactor has been maintained in between the equilibrium pressure of pure methane hydrate and methane hydrate in the presence of PEG using a back-pressure regulator. The injection of PEG aqueous solution has been performed at 0.4 mass fraction for methane recovery from the artificial hydrate reservoir. PEG-200 aqueous solution has shown a methane gas production ratio of 47.38%. This work provides a practical approach to use polymer as an effective inhibitor for the production of methane from hydrate reservoir especially for low temperature and permafrost hydrate-bearing zones. This is the first work that uses an environmental friendly polymer as inhibitor for the hydrate dissociation for methane production from a natural gas hydrate. It has been observed that PEG performs well as a thermodynamic and kinetic inhibitor. In addition, PEG is having −65oC freezing point, which is more than a commercial inhibitor, ethylene glycol (-13.4oC), therefore using PEG as an inhibitor is more beneficial for the production of gas from a low-temperature hydrate reservoirs.
Risk-Based Flow Assurance Design for Natural Gas Hydrate Production Systems
Authors: Norris Bruce W. E. , Charlton Thomas B. , Johns Michael L. , May Eric F. , Aman Zachary M.
Published: March 2018

Transport in subsea gas gathering networks of hydrocarbons liberated from natural hydrate deposits poses many of the same risks as faced in more traditional hydrocarbon production. There is an inherent need to ensure that these fluids do not recombine into hydrates within the flow network, a familiar problem in flow assurance. This paper describes a risk based approach to assessing hydrate formation in the transport flowline of a produced hydrate deposit. The bathymetry is typical of those found off the Australian coast, with fluid properties as expected for a methane rich natural hydrate deposit. To fully assess the ‘risk’ of hydrate formation, probabilistic analysis based on Monte-Carlo simulation of the blowdown pressure and nucleation temperature are performed. This is coupled with targeted transient analysis of the severity of hydrate formation using a new plugin for OLGA®, which focuses on the mechanics of hydrate formation in gas dominant systems.