bluuebunny/crossref_metadata_2025 huggingface dataset:
Subspace Clustering for High-Dimensional Data Using Cluster Structure Similarity
Authors: Fatehi Kavan , Rezvani Mohsen , Fateh Mansoor , Pajoohan Mohammad-Reza
Published: April 2018

This article describes how recently, because of the curse of dimensionality in high dimensional data, a significant amount of research has been conducted on subspace clustering aiming at discovering clusters embedded in any possible attributes combination. The main goal of subspace clustering algorithms is to find all clusters in all subspaces. Previous studies have mostly been generating redundant subspace clusters, leading to clustering accuracy loss and also increasing the running time of the algorithms. A bottom-up density-based approach is suggested in this article, in which the cluster structure serves as a similarity measure to generate the optimal subspaces which result in raising the accuracy of the subspace clustering. Based on this idea, the algorithm discovers similar subspaces by considering similarity in their cluster structure, then combines them and the data in the new subspaces would be clustered again. Finally, the algorithm determines all the subspaces and also finds all clusters within them. Experiments on various synthetic and real datasets show that the results of the proposed approach are significantly better in quality and runtime than the state-of-the-art on clustering high-dimensional data.
Building Textual OLAP Cubes Using Real-Time Intelligent Heterogeneous Approach
Authors: Alzeini Haytham , Hameed Shihab A. , Habaebi Mohamed Hadi
Published: April 2018

This article describes how the ever-growing amount of data entails introducing innovative solutions in or-der to capture, process, and store the information. OLAP has been considered a powerful analytical technology that enables analysts to gain insight into data and project information from diversified points of view. Thereupon, OLAP has been utilized in a broad spectrum of sensitive applications in the industry. The technology has occupied its place at the forefront of the vibrant information technology landscape of research in order to meet the evolving needs. One of these needs that has enticed the researchers' attention is providing real-time answers which suggests, in particular cases, processing billions of records in few seconds or less. The limited processing capacities have arisen as a major hurdle in the way of achieving such an aim. Although numerous improvements have been suggested, few have considered the heterogeneous computing approach, whereby quantum leap in terms of the response time has been achieved, albeit in most cases, only numerical data have been utilized. In this article, the authors introduce a novel heterogeneous OLAP approach targets textual OLAP cubes aggregation and can be utilized efficiently in OLAP-based pattern recognition problems. In this context, the approach (a) exploits the GPU along with the CPU in order to process textual data. (b) Stores the queries aggregations' hash table in the global memory such that the higher aggregations levels are being answered in a shorter time (c) Introduces an intelligent self-evaluating mechanism (ISEM), that evaluates the resource efficiency on query-basis by deciding which resource (CPU or GPU+CPU) is more reliable to process each query. The authors' empirical results have shown the achieved gain is up to thirty-two folds over the parallel CPU-based counterpart solution. Furthermore, their approach has demonstrated that adopting aggregation-memory optimization significantly improves the performance of high-level textual aggregations.
Are Timing-Based Side-Channel Attacks Feasible in Shared, Modern Computing Hardware?
Authors: Montasari Reza , Hosseinian-Far Amin , Hill Richard , Montaseri Farshad , Sharma Mak , Shabbir Shahid
Published: April 2018

This article describes how there exist various vulnerabilities in computing hardware that adversaries can exploit to mount attacks against the users of such hardware. Microarchitectural attacks, the result of these vulnerabilities, take advantage of microarchitectural performance of processor implementations, revealing hidden computing process. Leveraging microarchitectural resources, adversaries can potentially launch timing-based side-channel attacks in order to leak information via timing. In view of these security threats against computing hardware, the authors analyse current attacks that take advantage of microarchitectural elements in shared computing hardware. This analysis focuses only on timing-based side-channel attacks against the components of modern PC platforms - with references being made also to other platforms when relevant - as opposed to any other variations of side-channel attacks which have a broad application range. To this end, the authors analyse timing attacks performed against processor and cache components, again with references to other components when appropriate.
Towards Big GeoData Mining and Processing
Authors: Boulaaba Aroua , Faiz Sami
Published: April 2018

The proliferation of advanced technologies and the rapid adoption of connected devices and mobiles were behind the tremendous growth of geographic data introducing the concept of Big GeoData. The extraction of useful patterns is an interesting process, but the specific features and the complexity of relationships among spatial objects outpace the capacities of current systems. The unique way to tackle challenges raised by Big GeoData is to develop new platforms and systems. To discuss this topic, this article starts with an introduction of Big GeoData and spatial data mining tasks, followed by a reviewing of works made on Big GeoData analytics as well as their issues. Finally, authors propose their approach to develop a tool allowing the analysis of Big GeoData. This tool will encompass a wide range of algorithms and techniques to carry out most of the data mining tasks.
Peer Interactions
Authors: Chadha Anita
Published: April 2018

The focus of this article was to evaluate a specifically designed digital learning peer-interactive strategy through an e-collaborative web project for reflective engagement with each other and associated academic materials. Data was taken from one semester of participation in an e-collaboration assessing student peer discussions in politics from two introductory American politics classes across two geographic regions of the country. Significant findings reveal that the interactive discussion forums in this e-collaboration engaged students in an academically reflective peer-student and peer-content interactions over the entire semester. The implications of this study are immense, in that a carefully designed digital learning strategy, an e-collaboration, does extend peer deliberative discussions into the virtual hallway, enhancing student deliberative performance. This is one that can be used to complement a variety of disciplines and is a concern to researchers, educators, and universities.
A Proposed Cohesive Use of Online Discussion Board from the Aspects of Instructional and Social Interactions in Engineering Education
Authors: Tai Yaming , Ting Yu-Liang , Tseng Teng-Hui
Published: April 2018

This article uses instructional and social interactions in the current era of networked learning as a conceptual metaphor to guide the design of engineering learning practice. Because of students' digital literacy and their customary means of acquiring information and peer-to-peer interaction, researchers have also explored the potentials of implementing social networks for student learning. This article values these two trends and explores how both mechanisms can be implemented in an engineering course. The topics delivered to students should be based on the needs of daily life. In addition, students in online discussion board-related learning are introduced to discussing their works. A learning activity design is proposed with the aim of providing a richer understanding of the interactional relationship between instructional and social interactions regarding the use of online discussion boards. The main findings reveal the importance of re-designing the online discussion board to bridge students' study between in-class and out-of-class discussion.
Internet Political Participation and Public Agenda-Setting
Authors: Weng Shihong
Published: April 2018

There are growing calls for social network analysis methods to be more extensively deployed in governance practice and research. This article develops a formal framework for whether and how netizens change the model of public agenda setting through internet political participation. Drawing on the case of “PX Event in Zhangzhou,” this article aims to explore the social network structure in the process of micro-blog public opinion diffusion in public agendas based on SNA. By introducing the relevant theories into the research of public agenda setting, and focusing on the practice by which local governments do urban governance under the environment of internet political participation, the analysis reveals that the new whole network structure based on new media changes the action of social actors, in which consistently the mode of public agenda-setting is transformed from the traditional one-way to the interactive-way. This article extends the existing research discourse domain of public agenda setting and government response, further generalize the “Queen Bee mode” of government response.
First Report on the Validated Classification-Based Chemometric Modeling of Human Rhinovirus 3C Protease (HRV 3Cpro) Inhibitors
Authors: Amin Sk. Abdul , Adhikari Nilanjan , Gayen Shovanlal , Jha Tarun
Published: April 2018

Human rhinoviruses (HRVs), a major cause of common cold and upper respiratory infections, may trigger severe respiratory complications like asthma and COPD. To date, no drugs are available in the market which are designed as novel HRV inhibitors despite the involvement of some pharmaceutical companies' due to economical and clinical constraints. HRV 3C protease may be a potential target for drug design as it plays crucial role in viral RNA replication and virion assembly process. Therefore, designing novel HRV 3Cpro inhibitors is necessary and demanding in the field of antiviral drug design. In this article, statistically significant and validated classification-based QSARs of a series of HRV 3Cpro inhibitors were performed for the first time as per the authors' knowledge. Results suggest that oxopyrrolidine and piperidinone rings are favored whereas carboxybenzyl and unsubstituted benzyl functions may be unfavorable. Moreover, this group, along with cyclic alkyl or aryl ring structures may favor HRV 3Cpro inhibition. These observations may be utilized for the design of a higher active anti-HRV agent in future.
QSAR Modeling Using Quantum Chemical Descriptors of Benzimidazole Analogues With Antiparasitic Properties
Authors: Jardinez Christiaan , Medina-Franco José L
Published: April 2018

This article describes how benzimidazole is a privileged scaffold that has been used as a basis to develop antiparasitic compounds. Herein, the relationship between the chemical structure and biological activity against Trichomonas vaginalis of sixty nine benzimidazole analogues was studied using Density Functional Theory and multiple linear regression analysis. The best QSAR model obtained highlights the correlation between the pIC50 with frontier orbital energy gap, Van der Waals volume, number of hydrophobic atoms, Harmonic Oscillator Model of Aromaticity Index, partition coefficient, and number of total second C(sp3). The model has values of R2 = 0.784, Q2 = 0.720 with the validation parameters: F-test = 37.51, SPRESS = 0.274, and SDEP = 0.262. The average values of R2adj (Obs) and (Calc) are very close (0.763 and 0.760 respectively), which suggests a relatively stable predictively of the model for these data. The QSAR model developed can be employed to estimate the biological activity of new compounds based on a benzimidazole core scaffold.
Computational and Metabolic Studies on a Set of N-Myristoyltransferase Inhibitors Against Trypanosoma Brucei
Authors: Scotti Luciana , Ishiki Hamilton , Junior Francisco Jaime Bezerra Mendonça , Ribeiro Frederico Fávaro , Yarla Nagendra Sastry , Sobral da Silva Marcelo , Filho José Maria Barbosa , Scotti Marcus Tullius
Published: April 2018

This article describes how the Human African trypanosomiasis (HAT) is a neglected disease caused by Trypanosoma brucei. Only four drugs are available for treating HAT. Despite years of effort, little progress has been made in identifying orally available chemotypes active against the parasite. In this study, chemometric tools, such as, Principal Component Analysis (PCA) and Partial Least Squares Regression (PLS), were applied to a set of active trypanocidal N-Myristoyltransferase inhibitors. These tools were generated using the Pentacle software. The algorithm (AMANDA), the descriptors are calculated through the molecular interaction fields with the blocks: N1, O, TIP and N1, which allow extracting from them the most interesting regions. The PCA selected 507 descriptors and the scores plot clearly separated more active compounds from others. The first two PCs account for over 70% of data variance. The best PLS model, exhibits q2 = 0.762 and r2 = 0.867 and rext2 = 0.69. The results highlight the importance of acceptor hydrogen bonds regions. The importance of the metabolic cleavage of the methyl group attached to the nitrogen of pyrrole ring by N-dealkylation was observed.
Predictive Value of CD3, CD8, CD45RO Expression in Stage II/III Colorectal Cancer
Authors: Argyropoulos Theodoros , Foukas Periklis G. , Karakitsou Effrosyni , Konstantoudakis Stefanos , Kefala Maria , Koufopoulos Nektarios , Machairas Nikolaos , Panayiotides Ioannis , Triantafyllou Konstantinos
Published: April 2018

This article describes how colorectal carcinomas (CRC) are the fourth most frequently diagnosed cancer. However, despite advances in specific treatment, approximately 40% to 50% of patients have disease recurrence following potentially curative surgery, highlighting the demand for improvement of staging, treatment and prognosis. Inflammatory infiltration composed of lymphocytes is a common feature found in neoplasms and studies have indicated an association between tumor immune infiltrates and favorable disease outcomes. The aim of this article is to assess the association of tumor infiltrating lymphocytes and DNA damage response expression levels with disease outcome and survival in stage II and III CRC. The authors examined the prognostic value of immunological biomarkers using 5-year follow-up data to train an Artificial Neural Network (ANN) designed for the prediction of personalized risk. Data for three biomarkers which were found significant were subsequently used to train the ANN which predicted 5-year survival with 72.9% sensitivity and 68.8% specificity.
Cognitive Biases, Risk Perception, and Individual's Decision to Start a New Venture
Authors: Zaiane Salma , Ben Moussa Fatma
Published: April 2018

The purpose of this article is to investigate the relationship of overconfidence and illusion of control towards the start of new venture, taking in consideration the mediating role of risk perception in the context of Tunisia. This article examines students' responses to surveys based on a teaching case titled “Optical Distortion, Inc.” The authors tested hypotheses by correlation and regression analysis. The results show that the perception towards risk associated with new venture plays an important role in decision-making. Moreover, they find that overconfidence and illusion of control reduce risk perception associated to the decision to start a venture. While overconfidence directly affects the decision to start a venture and indirectly through its effect on reducing the risk perception, illusion of control has neither a direct nor an indirect impact on that. These results partially confirm those of Simon show that the mediation exists but partially.
Filling Gaps in SIS Standards for Reliable, Cost Effective Safety Solutions
Authors: Statham Shawn
Published: April 2018

Automated Safety Instrumented Systems (SIS) have evolved dramatically over the last 20 years becoming critical for mitigating risk and ensuring plant safety in the offshore and process industries. Data from HSE studies (see Figure 1) reveal that 44 percent of failures in safety shutdown control systems are due to insufficient specification. Studies such as this resulted in the development of new safety instrumented system standards ISA84.01/IEC61511 and IEC61508. However, these standards have left end users with little guidance on how to integrate and test these systems. Compliance has grown complex and costly for systems that are often the last line of defense in protecting personnel, the environment and nearby communities.
Successful Operation of Fluid-Loss Isolation Barrier Valves in Debris
Authors: Craik Steven J. , Jannise Ricki , Barrios Oscar , Tocchetto Andre , Soares Robson
Published: April 2018

This paper demonstrates the importance of wellbore cleanliness during lower, intermediate, and upper completion installations that lead to both successful installation and operation of an isolation barrier valve. This should result in bringing the well into production or injection in a timely and efficient manner. Excessive debris remaining in the wellbore can complicate and delay production or injection and also compromise well productivity by causing damage and preventing installed equipment from operating properly. Post-production/injection debris in the well can also impact and affect production and injection rates.

Downhole tools in deepwater environments not operating remotely as designed because of debris can result in a complex and costly intervention. Typically, when this occurs, a drift or bailer run is conducted to establish holdup depth. In some cases, these have tagged up to 50, 80, and 100 ft (in extreme cases, 150 ft) above the valve expected to operate. Sometimes, slickline, electric line (e-line) bailers, coiled tubing (CT), or a work string with a Venturi junk basket are used, and then the valve is either functioned open or the debris is milled out and the valves remotely functioned cycled open once all the debris is removed. Additionally, cases have occurred where the debris is cleaned out, enabling the tool to function and open, depending on tool design. The tools can be designed and qualified to industry standards and tested at downhole conditions, pressure, and temperature with applied tubing and simulated hydrostatic pressure; however, this does not mean functionality cannot be impaired. The importance of wellbore and surface equipment cleanup should not be undervalued.

Wellbore cleanout, circulation, displacement, and correct conditioning of fluid are important during the final stages of the operation. If executed properly, these can result in the well entering production or injection on time and without issue. The criticality of robust procedures cannot be overlooked. Not only is it important to condition and displace drilling fluid with clean completion fluid, it is also important to ensure that all debris is removed, including jetting the blowout preventer (BOP) and wellhead cavities before running the completion. Additionally, particular attention should be given to the landing string, tubulars, and drillstrings used to land and lock the completion. All surface lines and pump cavities should also be cleaned before pressure testing. Due diligence during initial cleanout can enable successfully bringing the well on-stream and help prevent costly interventions.
4D-Close-the-Loop Workflow to Calibrate the Geomechanical Simulation Model and Identify Drilling Geohazards: Field Application
Authors: Nasser Yesser Haj
Published: April 2018

Anomalous time shift observations from 4D seismic data shot in an HPHT field in the North Sea are being investigated. We are using these time shift signatures to understand the dynamic geomechanical behaviors of two major shales units (Shale Ι and Shale ΙΙ) between the main producing sands.

To capture the geomechanical and pressure diffusion behavior in these shale units, we have performed a coupled fluid flow and geomechanical simulation. Next, we use a 4D-Close-the-Loop workflow to integrate reservoir simulation results, the rock physics model, and seismic signature into a comprehensive and iterative process to update the simulation model. In this process, geomechanical modeling and the conversion of model results to synthetic 4D seismic time shifts allow for a quantitative comparison of synthetic response with the observed 4D seismic anomaly.

The application of this hands-on approach has prompted the calibration of the fluid flow and the geomechanical properties of different reservoir units. Consequently, a better match between the modeled 4D seismic time shifts and those observed from the field data has been achieved. Furthermore, this calibration provides a model that more reliably predicts the pore pressure and stress tensor changes, allowing more confidence in selecting safe well paths. The calibrated geomechanical model suggests that Shale Ι, which is a silty marine shale, undergoes pressure diffusion, and therefore, the trapping mechanism of Shale Ι is highly uncertain. The clay-rich Shale ΙΙ, however, acts as an effective pressure barrier, and hence it is overpressured relative to the surrounding formations and could be a high-risk formation for future drilling programs.

In this case study, the application of the 4D-close-the-loop workflow allows the calibration of the geomechanical model, and hence a close examination of stress distribution at the level of Shale Ι and Shale ΙΙ. These findings have provided additional information that could identify potential geohazards and prevent the risk of well deformation and failure.
Experimental Investigation of the Ionic Strength Effects on Drag Reduction Characteristics of Polymer Solutions – Part I: Straight Tubing
Authors: Kamel Ahmed H.
Published: April 2018

It is well established that polymers are successful drag reducers due to their viscoelastic properties that can suppress the turbulence eddies and fluctuations and hence, reduce friction pressure losses. Various factors can affect the polymers’ drag reduction characteristics such as polymer type, concentration, shear degradation, and flow geometry. However, few studies have shown the effects of salt type and concentration on drag reduction characteristics with almost no studies discussing their effects in the light of the ionic strength. The ionic strength is considered a more widespread scale to quantify the effects of salt contents on a specific characteristic. This study is undertaken to better understand the relation between ionic strength and drag reduction performance of polymers in straight tubing.

For this purpose, two widely used anionic AMPS copolymers; Nalco ASP-700 and ASP-820, are investigated. The salt matrix includes 2% KCl, 4% KCl, and synthetic seawater. For synthetic seawater, different recipes exist. The recipe adopted includes 1.0 lb/bbl Na2SO4, 10.5 lb/bbl NaCl, and 0.4 lb/bbl CaCl2. A ½-in. OD flow loop with a 15-ft. straight tubing section is used.

The results show that drag reduction behavior is better correlated with the solution ionic strength, and not the salt concentration. Higher ionic strength yields lower drag reduction despite the lower salt concentration. However, the adverse effects of salt and its ionic strength diminishes as higher Reynolds numbers. Both ASP-700 and ASP-820 exhibit a very effective drag reduction behavior and their performance is significantly affected by the polymer type, shear rate, and salt content. Correlations between ionic strength and drag reduction ratio for both polymers are proposed. The correlations exhibit a reasonable agreement with the gathered experimental data. They can be used to quantify the adverse effects of different salt types and concentrations on drag reduction characteristics of polymers in straight tubing
Remediation of Subsea Flowline Restriction Using Seawater and Additives
Authors: Garan Ron , Esley John , Arciero Bryan , Mazzeo Claudia , Alapati Rama , Yousef Ali
Published: April 2018

Prior to a planned transition in producing zones, an 18,000′ single well subsea tieback flowline to a deepwater Gulf of Mexico production facility experienced a restricted flowline ID and partial blockages due to paraffin deposition. Efforts were coordinated to provide support in the design, product selection, and determination of success for the flowline remediation. Transient multiphase flow simulations were created and tuned/validated with historical slugging data to estimate initial effective ID of the subsea flowline. The models were then applied to the planned clean-out procedure to develop performance indicators during and after flushing operations. A two-step remediation consisting of a 24 hour hydrocarbon solvent/dispersant mixture soak, followed by a 4,000 bbl seawater and waterbased paraffin dispersant flush at increasing rates utilizing solvency, dispersancy, and shear was used to remove deposition and increase cross-sectional flow area of the pipeline by 85% (initial effective ID ~2.5 in., final effective ID ~3.4 in.). The procedures were created to minimize risk of packing solids following initial disaggregation, while maximizing effectiveness of the flowline clean-out within the economic constraints of a depressed oil market.
Development of a Casing-Integrated Well Control Tool
Authors: Owens Zach , Smyth Brian , Ames Nicoli , Pye John , Hilbert Lawrence , Brooks Bob
Published: April 2018

This paper documents an initiative to develop a surface-activated, casing-integrated, flow-restriction tool capable of arresting flow during an uncontrolled blowout. The tool is similar in function to a subsurface safety valve (SSSV) but is designed to fit directly into a 9-5/8-inch casing string. Unlike a SSSV, the well restriction tool (WRT) described here is intended for use during drilling operations and can be installed deep in the well near the end of the casing string. The WRT is intended to supplement the blowout preventer (BOP) by arresting the influx of hydrocarbons into the well thereby increasing the chances that the BOP can successfully close, and by serving as a backup in cases where BOP closure is unsuccessful. Actuation of the device is accomplished by remotely triggering the combustion of a propellant charge which drives a sleeve forward and releases six, spring-loaded, triangular fingers which come together to seal the wellbore. This work describes the conceptual operation of the WRT and the design basis for the tool; including, computational fluid dynamics (CFD) analysis and finite element analysis (FEA). Lastly, initial prototype testing will be presented culminating in a successful closure and leak proof hydrostatic test to 10,000 psi.
Marinization of Mass Transfer Columns for FLNG Applications
Authors: Schultes M. , Brauer J. , Chen P. , Doong S.
Published: April 2018

Marinization of mass transfer columns has been studied for decades, starting in 1947 by Weedmann and Dodge. Numerous papers have since been published for trayed and packed columns under motional conditions. Still today, there is limited information available about the predictive impact of column motion on the fluid dynamics and mass transfer efficiency of industrial-sized marinized columns. Raschig and UOP started a new approach in 2010 to evaluate the performance of random and structured packings during column motion. In a moving pilot plant, columns containing different random and structured packings have been investigated for a wide range of liquid loads with varied constant column tilt and different column motion frequencies. This paper compares the performance of random and structured packings used with different column tilts and motions and will provide information on when to apply one of these product lines.
Modular Compact Pump: A Game Changer in Subsea Multi-Phase Boosting
Authors: Melbø Aslaug , Glomsaker Terje , Sundt Hans Kristian
Published: April 2018

Oil companies are looking for ways to increase oil recovery rates. Subsea boosting can be a powerful tool, but investment costs are often too high, driven by expensive topside modifications and overall system cost. Operators also see other challenges for future boosting systems which are not currently solved by conventional systems, in particular being able to provide sufficiently high boost for deep, long tie-back fields, as well as avoiding a barrier fluid system.

The Modular Compact Pump (MCP) is a barrier fluid-less pump, based on an entirely new subsea pump architecture which enables flexible high boost solutions at low life cycle cost. Due to the novelty of the concept, with each impeller spinning independently, an early phase prototype approach was chosen to prove the feasibility, both electrically, hydraulically, and mechanically. A small-scale 3-stage prototype was successfully tested during the second half of 2017, and key results from the test are presented.
CVA for the Continued Service Process - A Proposal
Authors: Gallagher Dan , Spong Robert , Abadin Jose , Rose Christopher
Published: April 2018

For Continued Service (Life Extension) approval in the GOM, both BSEE and USCG require a review of the process and submittals by an independent third party. This has been referred to as a CVA review for lack of a better term, which is a Certified Verification Agent. However, the scope of a CVA review during a Continued Service Assessment does not typically warrant the extensive scope of the full CFR definition of a CVA as required for the design and installation of a new offshore facility, but guidance has not yet been provided by USCG or BSEE. As a result, there is currently uncertainty within the industry as to what the CVA role is for Continued Service and it is being applied using widely varying approaches, ranging from a simple review of the overall assessment documents and references to active participation in the entire process influencing decisions on analysis and mitigation requirements. Drawing upon the authors experience conducting Continued Service Assessments in the different roles of operator, assessment contractor and CVA, this paper describes the important role of the CVA as part of the Continued Service Assessment team, the CVA activities and interfaces, as well as the varying degree of required independent oversight for different proposed continued service circumstances. This paper focuses on structure, marine systems, moorings and, to some degree, risers. Topside process or process safety are not discussed although there is an analogue process that is conducted as part of an overall Continued Service Assessment.
20ksi 350F High Pressure High Temperature Enhanced Vertical Deepwater Tree Development: Simplify, Eliminate, Integrate
Authors: Kirk Allison Weber , Mook Erik Van , Lusquinos Thiago , Keller Matthew
Published: April 2018

This paper presents the development of the first Enhanced Vertical Deepwater Tree (EVDT) system rated for 20 ksi pressure and 35° F to 350° F temperature applications. This project was a joint venture with five major operators. This system was designed and qualified to API 17TR8 and internal requirements.

The 20 ksi system design was a progression of 15 ksi and 400° F development, therefore many components are common between the 15 ksi and 400° F system and the 20 ksi and 350° F system. The 20 ksi design reduces cost as compared to a traditional EVDT by utilizing methods of simplification, elimination, and integration without compromising functionality. The scope of this development included materials testing and qualification, elastomeric seals, metallic seals, gaskets, bolted flanges, a new family of gate valves and actuators, tubing hanger, tree components, and a series of connectors.

This was a four-year development project which included component design, Failure Mode Effect and Criticality Assessment (FMECA), prototype testing, validation testing, meetings with BSEE, and independent third party reviews of technical documentation.
Umbilical Cost Reduction and System Availability Improvement with Use of Chemical Injection Valves
Authors: Campos Murilo , Silva Simao , Smith Matthew
Published: April 2018

Including chemical injection valves (CIVs), also known as chemical-injection throttle valves (CTVs), in subsea architectures can provide significant cost savings during the field development phase, while improving overall system availability over the design life.

CTVs can create economic and operational benefits for multi-well developments by reducing the number of chemical injection tubes required in the umbilical. Subsea wells often require chemical injection into the production fluid to inhibit scale, corrosion, asphaltene, or hydrate formation that can compromise the flowline integrity and impact or impede production. Chemicals are conveyed from the host facility through small-diameter stainless steel tubes that are bundled in the umbilical, which can also include hydraulic, electric power, and communication lines. Traditional oil and gas fielddesigns call for a dedicated tube for each treatment injection point, which typically ranges from two to four per subsea tree, depending on the flow assurance requirements. CTVs precisely control chemical flow rate at the point of injection, thereby allowing a single chemical tube to serve multiple injection points. This reduces capital expense and enables longer tiebacks.

The tubes in an umbilical make up to 80% of the cost of that unit. The reduction in the quantity of chemical injection tubes can allow the operator to adopt a more robust spares philosophy for the remaining tubes, and, since CTVs can be easily replaced by the use of a remotely operated vehicle (ROV)support vessel, the resulting system can have significantly greater overall availability over the service life.

CTVs can also be applied in brownfield applications to restore chemical injection to the wells after tube blockage and enable field expansion without installing new umbilicals.
Vortex-Induced Vibration Effects of Production Risers in Proximity with Drilling Risers or Tendons
Authors: Allen Don W. , Liu Nicole
Published: April 2018

This paper examines the effects of ocean currents on the vortex-induced vibration response of deepwater tubulars, such as umbilicals, production risers, tendons, and drilling risers, in proximity. This issue has received very little attention by the industry yet potentially has substantial importance to the design of deepwater tubulars and platforms.

Experiments have been conducted in a current flume on tandem flexible tubulars with diameter ratios of 2:1 and 4:1. The smaller diameter tubular was placed in both the upstream and downstream positions, with the top and bottom locations spaced apart at three different distances. The tension was kept constant, but the current speed was varied. While both uniform flow and sheared flow tests were conducted, only the uniform flow tests are reported herein.

The response modes varied from about 1-6, so that they were sufficiently high to easily allow both single mode and multiple mode responses, of which both were prevalent throughout the testing program. While all of the tests were conducted at low Reynolds numbers, the results can be thoughtfully translated to most field applications.

The results describe the vibration and response characteristics of both the upstream and downstream tubulars for various configurations that were tested. Since a myriad of diameter ratios, separation distances, and flow velocities are possible with tubulars in the field, these tests have attempted to provide general insights into the responses of tandem tubulars with unequal diameters and, in some cases, offer guidance on limitations to the responses that can be used for offshore field designs.
Baldpate Integrity Management Plan: A Continued Service Case Study
Authors: Kitson M. , Ramsay D. , Kemp D. , Moslehy Y. , Sheppard R.
Published: April 2018

An effective Structural Integrity Management (SIM) program allows operators to manage structural risks and reduce the need for hazardous and costly underwater interventions. Inspection and operating decisions and costs are significantly affected by the SIM program definition and execution. This is particularly true for unique, deepwater assets like the Baldpate compliant tower, which features an innovative structural system and is among the tallest structures ever built. This valuable deepwater asset requires a well-executed SIM program to provide confidence that continued service and potentially expanded operations can be safely achieved.

Earlier studies had shown that fatigue sensitivities at critical locations could potentially limit Baldpate's useful life beyond the original 20 year target. In order to better understand the characteristics of this unique structure, a series of reassessment analyses were performed. These showed that fatigue sensitivities are not limiting factors for continued service of Baldpate, and the areas of fatigue sensitivity were incorporated into a long term SIM plan to focus future inspections and monitoring efforts. This paper provides details on the challenges facing the execution of the SIM plan, including benchmarking and verification performed for the Baldpate structure using field measurements, implementation of a real-time monitoring system, and targeted underwater inspections.

The dynamic behavior of axial tube guides, modeled using gap elements and surface friction, was identified as one of the more critical objectives to be addressed in the SIM plan. This posed a challenge since previous design and assessment efforts did not consider these components critical for global response. SIM options for these components were included in the plan, such as underwater inspections and on-site dynamic motion recording to examine the potentially undesirable behavior of these components. Undertaking these tasks led to affirmation of the structural reassessment results and facilitated development of new SIM resources. In particular, benchmarking the monitoring system provided Baldpate with constant surveillance of its condition. This real-time monitoring plan measures the dynamic characteristics of the tower under different load conditions to indicate when certain unique structural characteristics (e.g., axial tube motion within the guides) would affect the fatigue life of critical joints in the Baldpate tower.
Hebron's Labor Empowerment Strategy – A Legacy of Success
Authors: Haddock J.
Published: April 2018

The majority of the Hebron Platform construction and fabrication was performed in the Province of Newfoundland and Labrador (NL). The NL construction labor workforce is robust, capable and unencumbered by the diverse harsh environment throughout Atlantic Canada. The local labor technical skills have generally kept in step with technology. However the construction safety statistics available at the beginning of the project raised concerns. Special focus was placed on labor force engagement and safety culture to achieve a strong project safety performance.

This paper will outline the strategy implemented by Hebron to ultimately execute one of the safest construction projects in NL's history. In so doing, the Hebron Project created a lasting legacy of perspective, inclusiveness and accountability.
An Evaluation of Shear Testing Guidance and the Effects of External and Operational Loading on Pipe Shearability Using the Finite Element Analysis FEA Method
Authors: Hoefler John A.
Published: April 2018

Objective/Scope

The paper will evaluate all current and future shearing requirements such as API TR1, API 16A, and 30 CFR 250 and utilize a Finite Element Analysis (FEA) approach to virtually shear pipe and examine the effects of individual parameters on shear pressure.

Methods, Procedures, Process

Standards, Regulations and test protocols will be reviewed and compared to create recommendations for planning a shear test. FEA will be used to analyze how individual and/or combination of variables effect shear pressure. A baseline analysis will be performed using actual material properties of a pipe sheared in a laboratory. Once a baseline analysis is performed, separate analyses will be performed to study the effects of external loads and environmental conditions. The variables studied will be: TensionCompressionBendingInternal pressure of drill pipeWellbore pressureOffset pipe

Analysis of variables using the finite element method will facilitate review of variables by eliminating variations if this experiment were conducted in a laboratory such as pipe dimensions and tolerances, pipe material properties, and wear of testing equipment. FEA comparison can be performed at a fraction of the cost of full scale laboratory testing. Understanding the variables may highlight potential operational or procedural limitations, and improve the shear verification process defined in §30CFR250.732(b).

Results, Observations and Conclusions

Understanding all the variables may help to drive future shear testing requirements and analyze whether current testing protocols are adequate and potentially avoid unsafe operating conditions. The report will clearly demonstrate the effects that external loading and environmental conditions have on pipe shearing. The report will summarize all the guidance contained in industry specifications and regulatory requirements and provide recommendations for testing for both current and future requirements.

Novel/ Additive Information

The FEA program to be used is Abaqus Explicit with damage model. Shear damage can be simulated by "turning elements off" once the stress/ strain value has reached a critical point. Using the same geometry and mesh will allow for a true comparison of what effect each loading condition has on the shear force.
Effectively Harnessing Data to Navigate the New Normal: Overcoming the Barriers of Digital Adoption
Authors: Bailie Bruce , Chinn Matthew
Published: April 2018

In recent years, there has been a great deal of discussion surrounding the benefits and opportunities presented by digitalization in the oil and gas industry. However, little has been written on the slow adoption of digital solutions in O&G and some of the challenges facing operators. This paper aims to address these topics by outlining some of the primary barriers the industry faces as it forges ahead with Industry 4.0. Particular challenges that will be discussed include cybersecurity, the human resources / talent shortage, and a need for operators industry-wide to adapt their culture and business models to create an environment that fosters innovation, collaboration, and readily adopts news ways of working.

The paper will also look forward at potential future applications of digitalization in oil and gas, including how artificial intelligence (AI) and other ‘next frontier’ technologies have the potential to help operators unlock hidden value in untapped assets through acquisition and analysis of more data.
HSE Enhancements in Campos Basin
Authors: Harres D. A. , Mariano I. A. , Sant Ana T. D. , Deodoro B. A. , Junior D. L. Fonseca , Ferreira J. P. , Faria A. A.
Published: April 2018

Several actions have been implemented to strengthen process safety and improve safety culture involving Petrobras’ E&P activities in the Campos Basin - Brazil, such as Process Safety Program, Strategic Project Excellence in HSE, Evaluation of HSE Management, improvement of standards and procedures, creation of HSE Management Manual and E&P Safety Manual, among others.

Additionally, at regulatory sphere, new operational safety regulations were established by the Brazilian National Petroleum, Gas and Biofuels Agency (ANP; most acronyms derived from respective Portuguese expressions, throughout this paper), such as the Operational Safety Management System, Technical Regulation of the Subsea Systems Operational Safety Management System and Well Integrity Management System.

More than 400 million men-hour exposed to risk were employed on Petrobras offshore production facilities operations (owned and contractors, except drilling and logistics) in Campos Basin between 2010 and 2017. This number represents an increase of 43% when compared to previous decade, but the rate of time-lost injuries and recordable incidents decreased about 20% in the same period. All actions allowed a significant reduction in number of casualties in Petrobras offshore facilities operations – 01 casualty in the period.

Many other actions were deployed at drilling and logistics operations, also helping to achieve the reduction of accidents goals. Aviation's Safety Case, for instance, involves several actions, from helicopters’ companies, passing by airports, up to helidecks and offshore crew.

This work presents the main implemented programs and actions, as well as the challenges to comply with the various applicable laws, and the search for the zero accident objective in oil and gas production activities in the Campos Basin.
Single Trip, Multistage System Delivers Fast, Efficient Solutions in Deepwater
Authors: Johnson Michael , Stone Matthew , Falgout Matthew , Womble Allen , Andrew Colin , McGuire Adam , Treadway Travis
Published: April 2018

The Lower Tertiary Wilcox formations are hard rock, low permeability formations that contain billions of barrels of oil. Fracture stimulation is required to allow access to these reserves. Multi-zone, single trip (MZST) frac pack systems have been the lower completion method of choice to allow operators to reduce costs when completing these lucrative reservoirs. The use of MZST systems reduces the time required to complete these wells versus the conventional cased hole frac pack system methods. However, these systems are relatively expensive, complex, and have similar space out limitations as the conventional systems that restricts reservoir contact. Despite the large quantity of reserves and production potential of Lower Tertiary wells, the operating environment and costs required to access these reservoirs makes this a marginal play. In order to reduce the commercial risk associated with these reservoirs a step change, 30 to 50% reduction in well construction and completion costs, is required.

In order to achieve this cost reduction target, field proven unconventional multi-stage open hole stimulation technology was adapted for these reservoirs. Ball-activated multi-stage Frac sleeves with open hole packers, were integrated into deepwater operations to significantly reduce well construction and stimulation costs. The system design allows open hole deployment of a frac completion into a short radius borehole and the rapid stimulation of multiple zones in a single trip. As a result of this design, it is now possible to stimulate up to 22 stages and prevent the proppant from flowing back during production. In addition, the Frac sleeve system allows the operator to maximize production by strategically placing each zone in the optimum location based on LWD data with virtually no space out limitations. The stimulation design can then be optimized to ensure that the pay zone is properly stimulated while minimizing the risk of premature screen out. In addition, this system offers the only viable option for both casing and open hole should borehole sizes change as a result of geomechanical or drilling issues in the complex reservoirs. If the primary well design option for casing is not accomplished, adjustments can be made thereby eliminating the need to abandon or sidetrack the well. This paper will discuss the flexibility and cost savings that this system offers along with case histories and lessons learned from recent deployments in the Wilcox formations. A brief discussion of stimulation design will be included with regard to optimization of the frac stages and their interaction with the system. Detailed frac designs will not be included.