bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Use of CFD Simulations to Compare and Evaluate Different Sizing Algorithms for Three-Phase Separators
Authors: Ahmed Tariq , Hamad Faik , Russell Paul A. 
Published: October 2017

Abstract
This paper presents a comparative study of two commonly used three-phase separator design procedures; Arnold and Stewart and Svrcek and Monnery. The procedures were developed based on droplet settling and retention time theories for the separation of gas, oil and water and are known to predict different separator geometries for the same operating conditions. These procedures were constrained to allow optimisation of the design but details of the constraints applied on the rational for their application are not available. To better understand these constraints, the two procedures for sizing a three - phase horizontal separator equipped with weir plate were investigated. Each procedure was used to calculate the geometries for three different sets of flowrates namely; fixed oil with varying gas and water, fixed water with varying gas and oil and finally fixed gas with varying oil and water. The calculated geometries determined from each procedure were then investigated using ANSYS Fluent to determine the separation achieved. To ensure that the ANSYS Fluent simulations accurately defines the separation process, a small scale industrial separator was modelled. Simulation results in terms of the separator outlet quality predicted that the separator designed using Arnold and Stewart procedure has a greater separation efficiency than that designed by Svrcek and Monnery.
Application of Lasers for Perforation of Petroleum Wells
Authors: da Silva M. G. , Braga A. M. , de Faria G. V. , Rosario F. F 
Published: October 2017

Abstract
This thesis presents the results of a study evaluating the application of high powered lasers when perforating cement-lined wells in carbonate rock reservoirs. The focus is on the creation of lateral channels in the walls of the well to allow the flow of the oil into the well. Through an intensive literature review of the international patents published in the last decade, the current state-of-the-art use of lasers in the perforation of rocks was evaluated. Specifically, 226 patent documents were found to have been published since 2008, showing the great importance of lasertechnology in this field. The results of the microtomography analysis are presented, showing samples of the cement slurry formulation used in pre-salt wells and carbonate rocks with characteristics close to the ones found in these types of reservoirs. The fiber laserutilized presented an output of up to 1.5kW and a wavelength of 1,064µm. To evaluate the structure of the samples, X-ray tomography and microtomography were employed. The specific energy was estimated at 243 J/mm3 for the carbonate rocks. The final tests to represent the well architecture were realized with samples of liner/cement/carbonate. By means of lasers with the power of 1.5kW for 80 seconds, channels with 5mm diameters and 50mm depths were produced. The results obtained show, although only preliminarily, the potential of using this technology in perforation operations.
Evaluation of Gas Hydrates Operation Zone to Establish an Optimal Hydrate Management Strategy
Authors: Fossen Martin , Johnsen Heidi , Kilaas Lars , Shmueli Andrea 
Published: October 2017

Abstract
Years of research and development, as well as field experience has moved the hydrate management philosophy towards less conservative operations. Previously, the standard was to avoid gas hydrates altogether. Now, on the other hand, the industry is more often looking into how to "live with hydrates" meaning that they are willing to accept the risk of hydrate formation given that there are enough evidence that the hydrates will not plug the pipeline. This paper presents some of the experimental techniques and methods used to realize an effective hydrate management strategy by investigating hydrate properties with regard to plugging and possible slurry transport.
Developments and Optimizations in the Pre-Salt Risers Systems: From Initial Technical Challenges up to Future Expectations
Authors: de Oliveira R. Caldeira , Gasparetto V. , Oazen E. V. , Senra S. F. , Aguiar L. L. , Valença C. J. , Lima D. L. , Carrara W. , Lemos C. A. D. 
Published: October 2017

Abstract
This paper aims to describe developments in the Santos Basin Pre-Salt risers systems, which in some few years experienced many different concepts to overcome big challenges. This paper also describes initiatives to optimize configurations with evolution and maturity of riser technologies and expectations for future developments.
In Santos basin Pre-Salt cluster, due to the challenging environmental conditions, presence of H2S and CO2, water depth up to 2310m, production riser's insulation requirements, relatively high temperature and high pressure, the riser system design for this scenario was something innovative and challenging for the industry. Currently, due to lower oil prices, an even more complex scenario is in evidence, imposing even greater challenges for risers systems regarding cost reduction. The experience acquired with the implementation of the first projects was a key factor to find viable and comprehensive ways to optimize cost.
In approximately 7 years of production in the Santos basin Pre-Salt layer, oil production surpassed 1 million bpd by using several different riser concepts: BSRs (Buoy-Supported Risers), SLWRs (Steel Lazy Wave Risers), Flexible Lazy Wave Risers, Free Hanging Flexible Risers and FSHRs (Free Standing Hybrid Risers). Nowadays, with greater maturity and new design premises, considerable cost reduction results have been obtained, mainly motivated by the reduction of buoyancy modules and reduction of riser sections quantity in the flexible risers. For the future, there are other ongoing optimizations studies to apply both flexible and rigid risers in free hanging configuration.
In early stages of project development, an extensive engineering work on riser analysis, the establishment of new design premise and some changes on current design process were done through a joint effort by operator, partners and suppliers. These are key factors for the achievement of considerable cost reduction. The maturity reached with the riser system designs was obtained through several design cycles, whose process can bring more future cost reductions.
Study of the Effect of Monoethylene Glycol MEG on the Precipitation of Calcium Carbonate in a Pressurized Dynamic System
Authors: Kartnaller V. , Venâncio F. , Cajaiba J. , Rosário F. do 
Published: October 2017

Abstract
Scale build-up in petroleum production systems is a major impediment to efficient oil and gas production. Calcium carbonate is one of the most commonly occurring sources of scale, but the formation of gas hydrate is also a challenge, especially in offshore and subsea deep water production. Thermodynamic inhibitors like monoethylene glycol (MEG) are frequently used to prevent hydrate formation. This paper describes the influence of MEG on the calcium carbonate scaling time by using a Dynamic Scale Loop System (DSL). The study also examines the influence of temperature, pressure and salt concentration on the scaling time. Experiments were performed using a 25-1 fractional factorial experiment design. The experiments showed that as MEG content increases, the expected calcium carbonate scale decreases. In contrast, an increase in temperature, will increase the calcium carbornate scale, while pressure and salt concentration did not have a significant influence on their own. Furthermore, the paper describes the interaction between the variables under review. The interaction between pressure, temperature and MEG content results in an overall decrease in MEG performance to avoid scale build-up by changes in the system's viscosity. Finally, we determine that the increase of MEG content increases the time to reach full-scale blocking; thus, the results indicate that an inhibition of the calcium carbonate deposition occurs as the MEG content increases.
Integrated Solution for Deepwater Cementing Challenges: Case Histories
Authors: Brunherotto Leonardo , Ribeiro Danilo , Perez Miguel Vicente 
Published: October 2017

Abstract
The primary objectives of well construction are to maximize reservoir deliverability, reduce remedial operations, and minimize nonproductive time (NPT) during the drilling and cementing process. Challenges associated with designing and delivering dependable barriers in deepwater environments include low bottomhole circulating temperatures (BHCTs), temperature variance, narrow pressure margins, annular pressure buildup (APB), etc. Cementing operations in these conditions should be engineered such that the equivalent circulating density (ECD) does not exceed the fracture gradient during cement-slurry placement. Additionally, lost circulation materials (LCMs) should be incorporated into the cement slurry to help control loss zones. This paper discusses the field implementation procedures and the cement-slurry design tailored for deepwater wells in offshore Brazil, which helped minimize risks and achieve the zonal-isolation objectives for extending the life of the well.
Hydrogen Induced Cracking HIC Resistance in HSLA API 5L X65 e 5L X80 Steels
Authors: Aviles J. Quispe , Alonso-Falleiros N. , de Melo H. G. 
Published: October 2017

Abstract
In the oil and natural gas production chain the structures for transport and extraction of the product are damaged by the conditions they are exposed to, which generally contain H2S, reducing the properties and the good performance of these pipes. In this work, we studied an API 5L X65LMN tube and another API 5L X80 with different levels of C and, mainly, Mn and Nb. The inclusions were examined by optical microscopy (OM) and scanning electron microscopy (SEM), the microstructure was examined by scanning electron microscopy (SEM) and the chemical analysis by Dispersive Energy Spectroscopy (EDS) of the inclusions was performed. As for the hydrogen-induced crack resistance in H2S containing media, the procedures of NACE TM0284-11 were used. The materials were subjected to the HIC test in solution A saturated with H2S of said standard. After the HIC, the characterization of the samples by Scanning Electron Microscopy (SEM) was performed. The API 5L X65LMN tube showed inclusions homogeneously distributed in the matrix, whose classification was of the type oxide-sulphide fine series, with maximum size of 5.6 μm and rounded format mainly with presence of Ca, Al, Ti and Mn. For tube X80 Presented irregular inclusions of type D-globular oxide-sulfide sserie coarse with a maximum size of 7.2 μm, with presence of Mn, O and S inclusions, with respect to the microstructural characterization of the tube X65 presented ferritic matrix, with presence of microconstituent M / A (Martensita / Austenite) and perlite in the cross section with lamination direction and grain size of 6.8 μm, the API 5L X80 tube presented ferritic matrix, with presence of M / A (Martensite / Austenite) and maximum grain size of 4.6 Μm. The results of the Hydrogen Induced Cracking Resistance (HIC) tests showed that the API 5L X80 tube showed cracks initiated on the D-globular oxide-sulphide coarse series inclusions, showing the deleterious effect of these inclusions on HIC resistance. It is important to note that the API 5L X80 tube has higher mechanical strength, which contributes to its lower resistance to HIC.
Stability Solver For Offshore Oil Flows
Authors: Andreolli Ivanilto , Azevedo Gabriel R. de , Baliño Jorge L. 
Published: October 2017

AbstractAn offshore flow system is designed to operate at steady state. However, it is possible that this condition does not exist. The stability of an offshore flow system depends on the set of parameters that defines the operational state and can be numerically determined. The stationary solution is given as initial condition for the numerical simulation; if the numerical solution does not go away from the initial condition with time, the stationary solution is stable and it is the system steady state. If the numerical solution goes away with time, the stationary state is unstable, there is no steady state and an oscillatory solution develops. As a numerically cost efficient alternative to time simulations, the linear stability theory is a powerful technique to identify the stable and unstable regions. This paper presents the main features of a stability solver developed for oil production systems. Numerical results are presented for two oil fields. Stability maps are obtained and compare to field data. The comparison showed an excellent agreement with the operational conditions presented.
Development of Alkoxylated Fatty Diamines as New Film-Forming Corrosion Inhibitors
Authors: Rabelo R. B. , De Rezende F. C. , Poltronieri O. C. , Ewbank C. G. , Velasco J. A. , Lima L. G. , Gonçalves I. L. , Freitas D. S. 
Published: October 2017

Abstract
Corrosion inhibitors are widely used to guarantee asset integrity from oil exploration and production stages (e.g. drilling equipment and metal piping in producing wells) to refinery, as well as during transportation of produced fluids and finished by-products. The major forms of corrosion found among the oil and gas industry include chemical, electrochemical, mechanical, and microbiologically induced. Corrosion inhibition by organic compounds is applied mostly in electrochemical corrosion due to acidic gases (H2S and CO2), from which CO2 corrosion is considered one of the major threats in oil and gas producing assets. According to the literature, amide and amine/diamine are the main classes of corrosion inhibitors used to combat sweet corrosion (CO2) in oilfields. However, the constant need to overcome new challenges makes it possible to create novel chemicals or to identify well-known molecules that can be improved in order to meet both the market demands and technical requirements, for example: guaranteed inhibitory capacity under several conditions, low emulsion and foaming tendency. In the present work, evaluations of different alkoxylation degrees and types of diamines were carried out in order to analyze the influence on the corrosion behavior of a carbon steel surface (SAE 1020 and API 5L X65), as well as emulsion and foaming tendencies. For these studies, the corrosion measurements were either performed by linear polarization resistance (LPR) or by weight loss measurements. The data revealed that their corrosion protection of carbon steel depended critically on the alkoxylation type and degree. Therefore, a suitable choice of molecule can create a tailor-made product to achieve specific requirements. The chemicals developed have shown good corrosion inhibiton performance and have satisfied defined pratical requirements to avoid emulsion and foaming tendencies.
HSE in Libra Project – Designing for Outstanding Performance
Authors: Bo Wang , Castro Fabio , Deplante Christian , Katekawa Marcel , Balint Stephen 
Published: October 2017

Abstract
The Libra project is exploring and developing a very large deposit of oil and gas in the pre-salt area of Santos Basin, 100 miles offshore Brazil's coastline. Five companies have come together in a consortium together with Pré-sal Petróleo SA (PPSA) to develop this area under the country's first Production Sharing Contract (PSC). While still in the exploration phase, the project has been moving at a rapid pace, creating full field development scenarios, drilling wells, developing a system to collect dynamic reservoir information, and preparing for the initiation of its first production FPSO project. Ultimately, the field could see the drilling of nearly a hundred deepwater wells and the installation of several very large FPSOs. The area will be active with seismic, drilling, construction, production, installation and support vessels for many years.
By applying industry safety statistics to the large number of man-hours required to bring these plans to life, the potential for fatalities, Lost Time Accidents (LTI's) and other HSE incidences associated with the project can be statistically extrapolated. With these figures in mind, Project Leadership embarked upon a program to substantially improve safety performance with an objective to not only develop this rare field efficiently, but to establish a legacy of exceptional HSE performance. Now three years into Libra's exploration and development, and already exceeding 20 million man-hours expended, this paper seeks to share the steps taken to improve the HSE Culture of the Libra team and the performance of its contractors and subcontractors. Examples of physical changes in specifications to improve process safety, and changes in leadership behavior will be cited. The paper will discuss the successes, challenges, and future opportunities, in the hope that broader discussion of these efforts will assist this project and the industry to achieve project objectives while assuring safe working environments.
Identification of Genetic and Epigenetic Variants Associated with Breast Cancer Prognosis by Integrative Bioinformatics Analysis
Authors: Shilpi Arunima , Bi Yingtao , Jung Segun , Patra Samir K. , Davuluri Ramana V. 
Published: October 2017

IntroductionBreast cancer being a multifaceted disease constitutes a wide spectrum of histological and molecular variability in tumors. However, the task for the identification of these variances is complicated by the interplay between inherited genetic and epigenetic aberrations. Therefore, this study provides an extrapolate outlook to the sinister partnership between DNA methylation and single-nucleotide polymorphisms (SNPs) in relevance to the identification of prognostic markers in breast cancer. The effect of these SNPs on methylation is defined as methylation quantitative trait loci (meQTL).Materialsand MethodsWe developed a novel method to identify prognostic gene signatures for breast cancer by integrating genomic and epigenomic data. This is based on the hypothesis that multiple sources of evidence pointing to the same gene or pathway are likely to lead to reduced false positives. We also apply random resampling to reduce overfitting noise by dividing samples into training and testing data sets. Specifically, the common samples between Illumina 450 DNA methylation, Affymetrix SNP array, and clinical data sets obtained from the Cancer Genome Atlas (TCGA) for breast invasive carcinoma (BRCA) were randomly divided into training and test models. An intensive statistical analysis based on log-rank test and Cox proportional hazard model has established a significant association between differential methylation and the stratification of breast cancer patients into high- and low-risk groups, respectively.ResultsThe comprehensive assessment based on the conjoint effect of CpG–SNP pair has guided in delaminating the breast cancer patients into the high- and low-risk groups. In particular, the most significant association was found with respect to cg05370838–rs2230576, cg00956490–rs940453, and cg11340537–rs2640785 CpG–SNP pairs. These CpG–SNP pairs were strongly associated with differential expression of ADAM8, CREB5, and EXPH5 genes, respectively. Besides, the exclusive effect of SNPs such as rs10101376, rs140679, and rs1538146 also hold significant prognostic determinant.ConclusionsThus, the analysis based on DNA methylation and SNPs have resulted in the identification of novel susceptible loci that hold prognostic relevance in breast cancer.
Civil society challenged: towards an enabling policy environment
Authors: Anheier Helmut K. 
Published: October 2017

Abstract
The roles of non-governmental or civil society organizations have become more complex, especially in the context of changing relationships with nation states and the international community. In many instances, state-civil society relations have worsened, leading experts to speak of a “shrinking space” for civil society nationally as well as internationally. The author proposes to initiate a process for the establishment of an independent high-level commission of eminent persons (i) to examine the changing policy environment for civil society organizations in many countries as well as internationally, (ii) to review the reasons behind the shrinking space civil society encounters in some parts of the world and its steady development in others, and (iii) to make concrete proposals for how the state and the international system on the one hand and civil society on the other hand can relate in productive ways in national and multilateral contexts.
Coccolithophore fluxes in the open tropical North Atlantic: influence of thermocline depth, Amazon water, and Saharan dust
Authors: Guerreiro Catarina V. , Baumann Karl-Heinz , Brummer Geert-Jan A. , Fischer Gerhard , Korte Laura F. , Merkel Ute , Sá Carolina , de Stigter Henko , Stuut Jan-Berend W. 
Published: October 2017

Abstract. Coccolithophores are calcifying phytoplankton and major contributors to both the organic and inorganic oceanic carbon pumps. Their export fluxes, species composition, and seasonal patterns were determined in two sediment trap moorings (M4 at 12° N, 49° W and M2 at 14° N, 37° W) collecting settling particles synchronously from October 2012 to November 2013 at 1200 m of water depth in the open equatorial North Atlantic. The two trap locations showed a similar seasonal pattern in total coccolith export fluxes and a predominantly tropical coccolithophore settling assemblage. Species fluxes were dominated throughout the year by lower photic zone (LPZ) taxa (Florisphaera profunda, Gladiolithus flabellatus) but also included upper photic zone (UPZ) taxa (Umbellosphaera spp., Rhabdosphaera spp., Umbilicosphaera spp., Helicosphaera spp.). The LPZ flora was most abundant during fall 2012, whereas the UPZ flora was more important during summer. In spite of these similarities, the western part of the study area produced persistently higher fluxes, averaging 241×107 ± 76×107 coccoliths m−2 d−1 at station M4 compared to only 66×107 ± 31×107 coccoliths m−2 d−1 at station M2. Higher fluxes at M4 were mainly produced by the LPZ species, favoured by the westward deepening of the thermocline and nutricline. Still, most UPZ species also contributed to higher fluxes, reflecting enhanced productivity in the western equatorial North Atlantic. Such was the case of two marked flux peaks of the more opportunistic species Gephyrocapsa muellerae and Emiliania huxleyi in January and April 2013 at M4, indicating a fast response to the nutrient enrichment of the UPZ, probably by wind-forced mixing. Later, increased fluxes of G. oceanica and E. huxleyi in October–November 2013 coincided with the occurrence of Amazon-River-affected surface waters. Since the spring and fall events of 2013 were also accompanied by two dust flux peaks, we propose a scenario in which atmospheric dust also provided fertilizing nutrients to this area. Enhanced surface buoyancy associated with the river plume indicates that the Amazon acted not only as a nutrient source, but also as a surface density retainer for nutrients supplied from the atmosphere. Nevertheless, lower total coccolith fluxes during these events compared to the maxima recorded in November 2012 and July 2013 indicate that transient productivity by opportunistic species was less important than background tropical productivity in the equatorial North Atlantic. This study illustrates how two apparently similar sites in the tropical open ocean actually differ greatly in ecological and oceanographic terms. The results presented here provide valuable insights into the processes governing the ecological dynamics and the downward export of coccolithophores in the tropical North Atlantic.