bluuebunny/crossref_metadata_2025 huggingface dataset:
Clinical Activity of Ipilimumab in Acral Melanoma: A Retrospective Review
Authors: Johnson Douglas B. , Peng Chengwei , Abramson Richard G. , Ye Fei , Zhao Shilin , Wolchok Jedd D. , Sosman Jeffrey A. , Carvajal Richard D. , Ariyan Charlotte E.
Published: May 2015

Background.

Ipilimumab improves overall survival (OS) in advanced melanoma. Acral melanoma is an uncommon clinical subtype of this disease associated with poor prognosis. The clinical activity of ipilimumab has not been well-defined in advanced acral melanoma.

Methods.

We retrospectively reviewed the demographics, treatment history, and clinical outcomes for all patients with acral melanoma treated with ipilimumab from two academic centers between February 2006 and June 2013. Using Cox proportional hazards models, we assessed for factors that correlated with OS.

Results.

A total of 35 patients with acral melanoma received ipilimumab. Melanomas arose on volar surfaces (n = 28) and subungual sites (n = 7); stage M1c disease was present in 54%, and 45% had elevated serum lactate dehydrogenase (LDH). Best response by RECIST 1.1 criteria was complete response in 1 patient, partial response in 3, and stable disease (SD) in 4 for an objective response rate (ORR) of 11.4% and a clinical benefit rate (ORR + SD) at 24 weeks of 22.9%. Median progression-free survival was 2.5 months (95% confidence interval [CI]: 2.3–2.7 months); median OS was 16.7 months (95% CI: 10.9–22.5 months). Normal LDH and absolute lymphocyte count ≥1,000 at 7 weeks predicted longer OS. Immune-related adverse events (irAEs) were noted in 16 patients including 7 with grade 3/4 irAEs (20%).

Conclusion.

Ipilimumab is clinically active in acral melanoma with similar ORR and OS compared with unselected melanoma populations. Ipilimumab remains a viable therapeutic option for patients with advanced acral melanoma.

Implications for Practice:

Ipilimumab is a commonly used immune therapy that improves survival in metastatic melanoma. The clinical activity of ipilimumab in certain rare melanoma subtypes, such as uveal or mucosal melanomas, is suboptimal. Acral melanoma is another unusual subtype of this disease that arises on the palms, soles, and nailbeds. In this study of 35 patients with acral melanoma from 2 centers, ipilimumab was found to have activity that appears equivalent to unselected melanoma (response rate of 11.4%, median overall survival of 16.7 months). Ipilimumab remains a viable treatment option for this melanoma subpopulation.
Optimising construction with self-compacting concrete
Authors: Rich David , Glass Jacqueline , Gibb Alistair G. F. , Goodier Christopher I. , Sander Graham
Published: May 2015

Self-compacting concrete or self-consolidating concrete (as it is known in North America) (SCC) is used on the basis of its unique properties of flowability, passability and resistance to segregation. It requires no external energy to achieve full compaction, so is advantageous on site, but there is evidence that its higher cost is a significant barrier to greater adoption. The research entailed work measurement of 14 UK single-family home residential projects (eliciting data on construction time and labour productivity) and cost modelling of three slab scenarios (exploring the relationship between material and labour costs). The study found SCC was placed up to 73% faster than conventional concrete and, when labour and material costs are included, the supplier is able to price SCC to closely match conventional concrete, hence making SCC more viable for the contractor. This relationship between as-built costs for SCC and conventional concrete is clarified by developing Pmax, providing a new mechanism for understanding project profitability and viability of SCC.
Um Estudo sobre a Indústria de Transformação de Leite no Município de Serra Talhada – Pernambuco
Authors: Rodrigues da Silva Ana Maria , Sobral Marcos Felipe Falcão
Published: May 2015

A seca é um fenômeno climático que faz parte do semiárido nordestino. A cadeia produtiva de laticínios sofre fortes consequências com a falta de água. O presente estudo tem como objetivo analisar a cadeia produtiva de laticínios do município de Serra Talhada, em Pernambuco. Pretende-se identificar as empresas processadoras do leite, a quantidade e o destino da produção, as variáveis que, além da seca, interferem no desenvolvimento da cadeia. Foi utilizada como ferramenta metodológica a pesquisa aplicada descritiva com abordagem qualitativa. Foi possível identificar o tamanho e o destino da produção, além de variáveis como logística, tecnologia e treinamento que também interferem no desenvolvimento da cadeia. Tais variáveis interferem na produtividade, levando os laticínios a trabalharem com a capacidade mínima. A presente pesquisa é parte primária para conhecimento da cadeia, fazendo-se necessário conhecer as práticas dos produtores de leite, a cadeia a montante da produção. Milk Transformation Industry in Serra Talhada, Brazil ABSTRACT: Drought is a climate phenomenon of the semi-arid region in northeastern Brazil and dairy production chain is highly affected by lack of water. Current assay analyzes the productive chain of dairies in Serra Talhada PE Brazil. Milk-processing industries, amount and selling site of the product and other variables that interfere in the development of the chain are identified. A descriptive applied research coupled to a qualitative approach constituted the assay´s methodology. Production size and selling site plus logistics, technology and training which interfered in the development of the chain were identified. Variables interfere in productivity and make dairies function in a highly slim manner. Since current research is the basis for the knowledge of the chain, it is highly necessary to know the practice of milk farmers and the chain prior to production. KEYWORDS: Development; Milk-Processing Factories; Production; Productivity; Drought
Estudo das Práticas Orçamentárias de Cooperativas Agropecuárias de Santa Catarina
Authors: Pereira Vânia Maria , Lyrio Maurício Vasconcellos Leão , Lunkes Rogério João , Schnorrenberger Darci
Published: May 2015

O presente estudo tem por objetivo analisar as práticas orçamentárias adotadas pelas cooperativas associadas à Federação das Cooperativas Agropecuárias do Estado de Santa Catarina. De caráter descritivo, se utiliza de uma abordagem quantitativa para tratar o problema, por meio de aplicação de questionário elaborado a partir das principais características apontadas na literatura sobre as etapas do processo orçamentário. O questionário foi enviado às 12 cooperativas filiadas, obtendo uma amostra de 67% do universo, sendo as respostas compiladas e analisadas conforme previamente estabelecido no questionário. Concluiu-se que os gestores das cooperativas têm preocupação com o planejamento e alinhamento dos esforços de sua organização, pois a grande maioria realiza e aplica o planejamento estratégico e, em seguida, o traduzem em números com o auxílio do processo orçamentário em suas mais variadas etapas. Analysis on Budget Practice of Agricultural and Cattle-Breeding Cooperatives in Santa Catarina, Brazil ABSTRACT: Current paper analyzes budget practices by cooperatives associated to the Agricultural and Cattle-breeding Cooperative Federation of the state of Santa Catarina, Brazil. The descriptive research applies a questionnaire prepared from the main characteristics found in the literature on the stages of the budget process. The questionnaire was sent to 12 cooperatives and a 67% response sample was received, filled and analyzed as previously established. Results show that the cooperatives´administrators underscore planning and alignment of their organization´s efforts. Most perform and apply strategic planning and translate it in numbers by budget process in one of the different stages possible. KEYWORDS: Agricultural and Cattle-breeding Cooperatives; Budget Practices; Budget Process
Fair Trade como Alternativa para os Empreendedores Familiares: Um Estudo Exploratório
Authors: Salguero Justino , Claro Jose Alberto Carvalho dos Santos
Published: May 2015

O objetivo deste artigo é entender o conceito do Fair Trade e verificar se esta prática tem sido utilizada como forma de inclusão para os pequenos empreendedores brasileiros, bem como as perspectivas de crescimento desta modalidade de associativismo. O método utilizado foi o exploratório, baseado em revisão bibliográfica e documental das informações provenientes de organizações não governamentais, e de sítios das principais associações relacionadas a este assunto. A pesquisa revelou que o negócio do Fair Trade tem crescido mundialmente, sobretudo na Europa, por meio de associações privadas; contudo, no Brasil este tema ainda é incipiente, sobretudo com a participação de pequenos produtores agrícolas. A modalidade de recompensa via um prêmio ao empreendedor familiar é validada pela Teoria do Embeddedness; no entanto, tem sido contestada pelos pesquisadores que colocam a qualidade como primeiro atributo nas transações comerciais. Fair Trade as an Alternative For Family Entrepreneurs: An Exploratory Study ABSTRACT: Current paper focuses on Fair Trade and verifies whether such a practice has been employed as an inclusion form for small Brazilian entrepreneurs and whether there are any prospects of growth in such associations. The exploratory method was based on a bibliographical and documental review on information from non-government organizations and electronic sites of the main associations linked to the theme. Research revealed that Fair Trade has increased worldwide, especially in Europe, through private associations, even though in Brazil the theme is still fledging, especially among small agricultural producers. Recompense modality through a premium to the family entrepreneur is validated by the Embeddedness Theory even though it has been opposed by researchers who place quality as the prime attribute in all commercial transactions. KEYWORDS: Family Economy; Entrepreneurship; Small Producers
Canopy cover and drought influence the landscape epidemiology of an amphibian chytrid fungus
Authors: Beyer Stacy E. , Phillips Christopher A. , Schooley Robert L.
Published: May 2015

Batrachochytrium dendrobatidis (Bd) is a globally distributed fungal pathogen of amphibians that has caused amphibian population declines. Prevalence and infection intensity of Bd should vary spatially across heterogeneous landscapes because survival of the pathogen depends on environmental conditions including humidity and temperature. Wetland temperatures should vary with forest canopy cover, but few studies have examined the relationship between Bd prevalence and canopy cover. We sampled anurans for Bd at 33 wetlands in Illinois across a canopy cover gradient during the severe drought of 2012 and during more typical weather in 2013. We hypothesized that anurans from closed canopy wetlands would have higher Bd prevalence than anurans from open canopy wetlands because high canopy cover would prevent temperatures from exceeding Bd's critical maximum temperature as often. We used occupancy modeling to examine how Bd prevalence varied spatially in relation to environmental covariates, and to determine if weather conditions altered such relationships. We analyzed all common species combined and Spring Peepers (Pseudacris crucifer) separately. Bd was widespread among the study wetlands. During the drought year of 2012, however, Bd prevalence and infection intensity were substantially reduced. Although wetland temperatures were related negatively to canopy cover, the influence of canopy cover on Bd was complex. Bd prevalence for Spring Peepers was related positively to canopy cover during the drought, but not in the non‐drought year. Bd prevalence for all common species was not related positively to canopy cover in either year. Effects of other environmental covariates, such as water depth, also differed between years. Weather conditions had a large impact on Bd infection patterns, which makes predicting pathogen dynamics difficult. In the Midwest region of the United States, climate change models predict more frequent droughts, which may generally inhibit Bd while also altering the effect of environmental factors such as canopy cover on Bd prevalence for amphibians.
Characterization of the Driving Unit of Linear Submerged Double Acting Pumping System
Authors: Moreira André Pimentel , Lepikson Herman Augusto , Schnitman Leizer , Ramalho Geraldo Luis , Matos Francisco Frederico
Published: May 2015

This paper present the characterization of the driving unit of a rodless mechanical pumping device, named linear Mechanical Submerged Pumping of double effect (MSP) which is the subject of a recent patent application at the National Institute of Intellectual Property (BR 2013 10 7033422). This rodless pumping device consists of an alternative hydraulic piston adapted to operate partially or totally submerged in oil production wells. The device is also a viable alternative for pumping water from deep aquifers. The goal of this work is to characterize and identify the main components used in the MSP concept, using the operating parameters and dimensions of conventional artificial lift wells, available in the Laboratory of Artificial Elevation of the Federal University of Bahia (LEA/UFBA). Our results allow estimating the characteristics of the components required to meet the requeriments for production considering the operating parameters of MSP. This new method of artificial lift and the alternative method of pumping fluid of linear wells or with deviation, justify investment in the production of specific components as well as producing the prototype, testing and validating the apparatus using trading components.
Numerical Simulations of 3D Single-Phase Flow in a Stage of a Centrifugal Pump of ESP Systems
Authors: P. Maitelli C. W. , F. Bezerra V. M.
Published: May 2015

In the present work a mathematical model was developed to obtain numerical simulations to describe the 3D single-phase fluid flow within one stage of a centrifugal pump used in the Electrical Submersible Pumping (ESP) systems. Simulations were performed with ANSYS® CFX® software and the results for pressure fields and velocity profiles were analyzed and compared to pump manufacturer curves. Three non-structured meshes were evaluated and two turbulence models were implemented to verify convergence and the model precision.
Reuse Selection Criteria for Progressive Cavity Pumps Based on the Mean Time between Failure and Reliability Function for Each Pump Type in the Cira Infantas Field
Authors: Labrador Laura , Celis Jonathan , Martin José Luis , Rubiano Edward , Gutierrez Jahir , Monroy Manuel , Prada Jesus , Obregon Cristian
Published: May 2015

La Cira-Infantas (LCI) is Colombia's oldest oil field whose production started on April 18th, 1918. Since it is a mature field and is undergoing secondary recovery most of its wells have low flow rates (< 1000 BFPD). The wells require an artificial lifting system with low-cost installation and maintenance. For low flow and gassy wells in sandstone reservoirs, the Progressive Cavity Pump (PCP) system has been used since 2006.

It has been observed that the smallest percentage of PCP failures is due to the pump. When a pump fails, it is necessary to determine if a component should be reused. Currently, when any work is performed on a well, the pump is inspected with a borescope. When the results show that the pump efficiency is 50% or higher, it is considered reusable. In addition, corrosion, scale formation, wear and abrasion from reservoir fluids should be identified to determine if the pump can be reused.

A database was constructed of the history of the PCP in LCI. Each well had its run life, type of installed pump and the cause for any intervention. Thus, every pump model was classified, identifying all the interventions as pump failure or no-failure using failure codes. This data was used to obtain the Mean Time Between Failure (MTBF) calculation and its corresponding probability of survival, obtaining the initial criteria to reuse the pumps according to what was calculated and the experience and knowledge of the conditions in the field. This history, combined with the test bench efficiency analysis, assisted in determining if the pump was in good condition and a candidate for reinstallation.

Today, when a pump is pulled out and successfully passes testing, its information is compared against every pump in the database. This enables a prediction of how much longer the PCP will last. After the estimate of reliability is calculated, the decision is made whether to reuse it or to reject it.
Failure Index Reduction Strategy for Artificial Lift Systems in Cira Infantas Field
Authors: Monroy Manuel , Gutierrez Jahir , Prada Jesus , Martin Jose Luis , Rubiano Edward , Labrador Soraya , Celis Jonathan , Sales Paola de
Published: May 2015

The Cira Infantas Field is located in the Middle Magdalena Valley Basin. It was discovered in 1918, the first oil producing field in Colombia, reaching a peak production of 53,000 BOPD in 1939. The field has been subject to different methods of secondary recovery, gas injection and waterflooding since then. In 2006, a waterflooding redevelopment with injection-production system optimization was started. In the first year, oil production increased from 4,500 BOPD to 9,800 BOPD and injection increased from 12,000 BWIPD to 36,000 BWIPD.

After an increase of the Failure Index in 2012, the artificial lift team developed a strategy to reduce this performance indicator based on process improvements including supply chain, design, storage, installation procedures, well start up and well surveillance.

As of December 2014, the field has 1000 producing wells and 408 injectors. The most common artificial lift system (ALS) is Beam Pump (BP) with 760 wells; followed by Progressive Cavity Pump (PCP) with 135 wells; Electrical Submersible Pump (ESP) with 99 wells and Electrical Submersible Progressive Cavity Pump (ESPCP) with 6 wells. The main failure causes are associated with sand, corrosion (CO2 is present), poor monitoring and operation procedures among others.

The application of the Root Cause Failure Analysis, RCFA was the first step to identify the artificial lift problems to be solved. One of the first conclusions showed the necessity to redefine the production range for the different ALS. This is an example that the problems are not always associated to the reservoir fluids, leading the team to define a strategy that covers all stages where ALS's are involved. The new implemented strategy yield a reduction in the ALS failure index from 0.67 to 0.47 in just 24 months. The savings enabled the operation to carry out additional well work (Workover & Well service) without additional funding.
New Approach for Reservoir Management Through the Implementation of Slim ESP With Bypass System for Production Logging in a Field With Rod Pumping Systems
Authors: Azancot A.. , Saavedra P.. , Romero J.. , Navas E.. , Pabon M.. , Agudelo O.. , Hernandez D.. , Reyes J..
Published: May 2015

Casabe has been under waterflooding for more than 30 years. The heterogenities of the reservoir and the commigled injection implemented at the beginning of the waterflooding, resulted in early break through times. In 2007, selective injection was implemented allowing to inject separately in each layer and, therefore, to have injection distribution through Injection Logging Tools (ILT). However, producer wells are completed in commigled and with PCP or SRP systems, making difficult access the well to have any information about production distribution. At the current phase of the field development, the production distribution is key information for reservoir management to make decisions about short to medium plans to optimize production.

By pass systems has been used in 9 5/8” casings with enough room to set an ESP and a by pass system (Y-tool). In Casabe field, producer wells are completed with smaller casing diameter representing a real challenge due to the lack of space to accommodate an ESP with a bypass system.

This paper presents the sucessfull application of Slim ESP with by pass system installed in high water cut wells with 7” and 29 #/ft casing, to run conventional production logging tools to determine production distribution and to identify swept and damage zones, PI per layer, crossflow between layers and not producing zones. The challenge of production logging in this environment was not only related to the type of completion in Casabe field (completions with rods and smaller diameter), but also to the multilayer characteristics and high water cut which needed an especific set of tools and sensors to have the best accuracy in the oil and water distribution per layer. A Production Logging Tool of 1-11/16” and a set of 8 probes for bubble counting was a must to achieve the objectives, so the Slim ESP with bypass system was selected based on this condition. After reviewing several combinations, a Slim ESP 319 series and a bypass system with a drift of 2.087” was selected as unique solution. Producction logging has been perform for the first time in Casabe field with a conventional PLT, with no operational problems and with clear results related to oil and water production distribution allowing making short term decisions such as isolating swept zones, stimulating damaged zones or optimizing injection in delpeted zones, but also allowing to understand the real behavoir of the wells and reservoir with the current completion strategy which help to make medium term decisions about reservoir management and field development.
Production Optimization using Insert Progressing Cavity Pumps (I-PCP) and Hydraulic Equipment for Heavy Oilfields in Mexico
Authors: Carreno L. Jimenez , Barbosa C. Yudiche , Ramirez B. Villalobos
Published: May 2015

Implementation of compatible production technologies for extraction of heavy oil using progressing cavity pump (PCP) systems in three different oilfields: Altamira, Ebano, Panuco & Cacalilao; located in Northeastern Mexico. The optimization process was accomplished thru implementation of Insert Progressing Cavity Pumps (I-PCP) and hydraulic driveheads, in areas without electric power network, and high restrictions of well service rigs.

The project started with conventional PCP, and a second phase achieved an important operational improvement thru I-PCP and surface systems with smaller internal combustion engines in response to the operator's request for less fuel consumption. In 2008 January a conventional PCP was installed in the Franco Española-66 well (60 BFD & 1000 m lifting capacity), successfully operating for 2 years. Subsequently between 2008 and 2009, 32 additional PCP were installed, but the operator company had serious restrictions for optimization programs because of unavailability of well intervention rigs.

In response for January 2010, an I-PCP was installed in the Altamira-1022 well (189 BFD & 1500 m lifting capacity), for extraction of heavy oil (10-13 °API); the favorable results led to installation of over 200 additional PCP systems in shallow wells (<450 m). At the same time, 80 power generators as surface equipment were installed in Ebano field; this due to the absence of electricity in the area. Those generators used 4.3 and 5.7 liter internal combustion engines. Those wells had low gas-oil ratio (GOR), therefore the use of natural gas obtained from annulus (casing-tubing) was not an option, so an outsourcing of Liquefied Petroleum Gas (LPG) was required. Considerable financial costs for high daily gas consumption were caused by this situation.

Facing this condition, the first hydraulic surface equipment with smaller capacity (3.0 L) was installed for January 2012, showing a decrease in gas consumption and lower costs. Likewise, the new application was focused on shallow wells, during next two years, in which all of the initial engines were replaced.

This PCP optimization process showed several positive economic impacts: Decrease of intervention rig frequency regarding former PCP systems installed, which demanded pulling of production tubing string.Saving in time and cost in front of PCP failures due to lower operating time using flush-by units, in comparison with bigger intervention rigs; i.e., workover or maintenance rigs.Lower deferred production levels were obtained.Additional cost saving associated to the consumption of LPG.

Implementation of this PCP process as artificial lift system for heavy oil wells achieved important improvements regarding operational performance and well productivity.
Three-Dimensional Model for Rod String Stress and Fatigue Calculations in Progressing Cavity Pumping Wells
Authors: Assmann Benno
Published: May 2015

This paper presents a 3D vectorial approach model that is capable of calculating traction, bending, cutting effort and torsion stress which are combined through Von Mises’ theory and applied to Goodman fatigue stress analysis and contact load distribution for guide distribution.

Geometry is described by a 3D model that determines tangent, normal and binormal vectors. This model allows calculating Cartesian coordinates and curvature from wellbore drilling data: measured depth, inclination and direction. Using geometry and curvature it is possible to calculate alternating bending effort that adds and subtracts from traction, besides other orthogonal shearing stresses, like cutting effort stress generated by contact load and friction that is added to torsion. These types of stresses are combined and applied through the applicattion of Von Mises’ Theory and Goodman's Analysis in order to verify rod string sizing.

A three-dimensional model is applied to develop an algorithm to perform stress calculations and analysis in a deviated geometry well and this algorithm is included in design software that makes all the possible combinations of rod strings, pumps, tubings, driveheads and prime movers, selecting the best suited combination by the fuzzy logic method. Some well designs are presented and stress analysis results are compared with commercial software results and the differences are highlighted and analysed. These designs include geometry, curvature and stress components, torque, load, fraction of rod strenght, contact loads and guide distribution along well profile. The algorithm includes contact load calculations and optmized rod guide distribution. Applying this model, rod string performance and MTTF can be improved in deviated wells by taking into account stresses that appear in this type of well and they are frequently not considered.

This model combines additional existing stresses in a deviated well like: bending, cutting shear, contatc friction stresses and compose weight and curvature contact loads resultant in inclined plane curve, in a more accurate approach. The fuzzy logic method, which automatically selects the best equipment combination, is another novelty.
Electric Submersible Pumping, First Application in a Mature Field in Mexico, Using the Unconventional Technology With Synchronous Permanent Magnet Motor (PMM) + “Power Save” Pump
Authors: Garcia Edgar Lopez , Gonzalez Jaime Sanchez , Torales Felipe L. , Campos Israel Molina , Gonzalez Fernando J. , Gonzalez Jose R. , Hernandez Edsel J. , Tapia Ramon
Published: May 2015

To share and divulge lessons learned using ESP system first application in a mature field operated by Petrofac Mexico, using cutting-edge technology and an Electric Submersible Pump (ESP) system with synchronous permanent magnet motor (PMM) + Power Save pump in Santuario 132 well, operated by Petrofac Mexico at the service of Petroleos Mexicanos (Pemex), for 384 days.

In this technical work the ALS selecting process is explained in detail, as well as new technology implementation in ESP systems with synchronous permanent magnet motor (PMM) + Power Save pump with staged vortex type semi-compressors, in the Santuario 132 well, operated by Petrofac Mexico for Pemex, is presenting the recommendations and good practices carried out mainly in the phases : Conceptual (design, specifications and manufacturing), Installation (assembly and commissioning), Operation (operational reliability and optimization), Out of Operation / Fail (methodology for analyzing the fault); phase Removal (analysis and inspection system) and last phase learning (change in design or procedures).
Modeling and Automatic Control in Artificial Lift using Smart Fields Technologies
Authors: Torres L. H. , Souza L. d. , Schnitman L.. , Lepikson H. A.
Published: May 2015

The production and operations in oil and gas fields are getting more complex, with more and more demanding restrictions for safety, energy efficiency, environment, which sets new technical challenges for automation and control. On the other hand, modeling and system identification tools and advanced control systems can be an important key to enhance stability and cost effectiveness and support the personnel (operators, engineers, etc.). This article will illustrate some results obtained with the application of modeling and advanced control systems for artificial lift using smart field technologies.
Determination of Downhole Dynamometer Cards for Deviated Wells
Authors: Araújo A. P. , Maitelli A. L. , Maitelli C. W. , Dos Santos D. P. , Costa R. O.
Published: May 2015

This paper proposes a numerical solution for the calculation of the downhole dynamometer card for deviated wells equipped with sucker-rod pumping. The solution shown is based in the model developed for the project of sucker-rod pumping systems considering three-dimensional trajectories. The results shown indicate that the incorporation of the three-dimensional model to the algorithm allows the adequate calculation of downhole dynamometer cards for vertical and deviated wells. The model enables the estimation of important productive parameters for any sucker-rod pumping system, such as flow rate and intake pressure, besides calculating significant data for deviated systems, such as lateral load acting throughout the rod string.
Computational Model of Heat Transfer in ESP System for Deviated Wells
Authors: Galvão H. L. , Oliva G. B. , dos Santos D. P. , Maitelli A. L. , Costa R. O. , Maitelli C. W.
Published: May 2015

Estimation of temperature effects on wells with artificial lift by Electric Submersible Pump (ESP) is necessary because heat transfer may interfere with fluid characteristics, motor behavior, cables and pump, affecting the whole system. This work presents and describes a computational model of heat transfer in ESP systems for multiphase flow in deviated wells.

The methodology adopted in this work considered geothermal gradient and the heat transfer between motor and production fluids. The geothermal gradient represents how temperature increases inside the well as the true vertical depth increases. For deviated wells, the well is divided by sections and temperature increase at each section is calculated as a function of its true vertical depth and the geothermal gradient. In the transfer of heat between motor and production fluids, calculated changes in motor and fluid temperature occur mostly by forced convection on account of high flow rates available in this artificial lift method.

The computational model was implemented in a program developed to simulate ESP system behavior. To validate developed modeling, results obtained through simulation of vertical wells were compared with field data obtained from wells equipped with bottom-hole sensors. These comparisons showed that calculated temperature values were similar to those obtained from a field data, implying satisfactory results. Deviated wells with ESP system were simulated and the results were also evaluated. Therefore, through analysis of the obtained results for thermal calculation in ESP systems, it is possible to verify if the equipment are working according to their specification, especially those related to the electrical system such as cable and motor.

In order to increase the ESP system efficiency, the results obtained through this work are useful for the development of studies focused on reducing harmful effects caused by the high temperatures present in this artificial lift method.
Well Performance and Production Optimization Through the Use of ESPs as Artificial Lift Method
Authors: Hartenbach Guilherme , Magalhães João , Belsvik Yngve , Pessoa Rui , Lemos Daniel
Published: May 2015

Peregrino field, a Statoil asset in Campos Basin approximately 85 km (53 miles) offshore from Cabo Frio/Rio de Janeiro state in Brazil, completes 4 years of production in April 2015 with the use of electrical submersible pumps as the primary artificial lift method. The oil in Peregrino is highly viscous, reaching up to 365 cP at reservoir conditions (234 bars and 82 °C), and API gravity varies between 13° and 15° API. The field development is accomplished by two drilling- capable wellhead platforms where produced fluids are transferred to a central moored floating production storage and offloading unit (FPSO) through booster pumps. There are 27 producer wells and 6 injector wells in operation. The field is producing close to 100,000 BPD of oil. In nearly 4 years of operation water cut has reached up to 95% in some of the wells and, within specific water cut range, emulsion has become a reality and a challenging factor for ESP operation.

Despite the shear effect that liquid undergoes in centrifugal pumps and sand control screens, during the field basis of design phase emulsions were not expected to be a big concern. However, some actions like downhole chemical injection were taken in case emulsions developed. Maximum viscosity considered was up to 2 times the oil viscosity at reservoir conditions and simulations showed acceptable pump behavior and production. On the other hand field experience has required simulator adjustments up to 11 times the PVT oil viscosity for water cut in the range of 30% and 60%. Empirical modifiers were obtained from controlled in-house loop tests to contemplate viscosity effects on pump head, flow and break horsepower simulations.

Due to the high emulsion viscosity, which generally leads to production loss and flow instability, the ESP performance has been severely affected. This has been observed as high differential pressure and motor electrical current fluctuations leading to possible fatigue of ESP internal components and production deferment. This paper describes the emulsion issues faced in Peregrino and the challenges to minimize their effects.

The objective of this paper is to describe the performance of the field, status and experience gained with Peregrino production regarding optimization and ESP performance.
Use of ESP Motor Cooling Systems
Authors: Mazzola Ricardo , Colla Miguel , Muñoz Heber , Bruni Marcelo , Teves Ricardo , Oyarzun Raul
Published: May 2015

In the last 5 years, GE Oil&Gas and Panamerican Energy worked on alternatives to produce Wells below perforations. All wells are produced by 3.75″ motor having refrigerating shrouds with very good performance. Today's failure index with this technology is 0.20. Besides the fact this is the simplest way to produce below perforations on vertical wells, having mentioned performance for high temperature and deep wells, it is required to overcome some limitations with this technology: In particular one of the problems that shrouded systems have in small series motors is the length of the equipment. This requires up to 30 meters achieving 100hp for a given rating. In general 4 to 5 motors are needed increasing installation time. Also, shrouds have the limitation on well's having doglegs: sometimes shrouds are lost during installation. Long shrouded equipment installed in small casing could also lead to some pressure drops due to scale deposition, reducing production capabilities.

This paper shows the experience in Pan-American Energy on alternative deployments below perforations having production recirculation tubes named Motor Cooling and Snorkel systems, and some comparative results with shrouded system.
Experience With Inverted ESP for Water Injection in Secondary Recovery Project
Authors: Tarabelli Mauro Luis , Blanco Armando , Oyarzun Raul , Russo Martin , Teves Ricardo
Published: May 2015

This paper presents the implementation of an inverted ESP pumping system for injecting water purposes in YPF SA.

In some fields, where it is not yet available facilities in the surface for water treatment and subsequent injection by mean of a conventional system, it is convenient to use an electric submersible pump installed in the injection well. This can be used for pilot testing in some potential areas to start a secondary recovery project. This well has an aquifer available which meets the technical and legislative conditions to be injected in another layer below. This second layer is of particular interest in starting secondary recovery tests.

Both layers are insulated by mean of a standard packer, locked before the ESP deployment.

In the upper side of the packer, the ESP is installed having instrumentation to monitor the water flow rate injected.

In particular this equipment has, unlike a conventional ESP, a seal and a centrifugal pump placed in the bottom side of the motor. A down-hole sensor is located at the top side where all equipment is hanging from.

This report will show the technical challenges and design criteria experienced by YPF SA and GE Oil & Gas for pump selection, instrumentation, fitting and accessories required for completion
Souring Development Associated with PWRI in a North Sea Field
Authors: Evans Paul , Nederlof Eduard , Richmond Will
Published: May 2015

A North Sea Field has been water flooded with commingled produced and aquifer water since 1997. Low- sulphate source waters were selected for injection in order to mitigate barium sulphate scaling and reservoir souring development. Small volumes of seawater are included in the injection water due to operational reasons, but the average sulphate concentration of the overall injection water does not exceed 20 mg/l. Aquifer and produced water has historically been injected with minimal treatment due to the high permeability of the clastic reservoirs.

Despite the low sulphate concentration of the injection water there has been souring development over field life. The reservoir temperature of 104 F is sufficiently low to allow microbiological activity throughout the reservoir. Microbiological monitoring in the produced fluids indicates the presence of sulphate-reducing bacteria (SRB), but the low sulphate availability limits SRB activity.

The injection water was treated with continuous biocide with the intention of controlling SRB activity within the reservoir, and reservoir souring simulations were carried out to investigate the effectiveness of this treatment. The simulation results indicated that the levels of H2S present in the produced water were consistent with the availability of sulphate in the injection water, and that the biocide treatment was not limiting SRB activity. The continuous biocide treatment was discontinued and no subsequent increase in H2S generation was observed in the field, demonstrating that souring development was sulphate limited.
Offshore IOR/EOR Implementation Through Weight and Footprint Reduction
Authors: Henthorne Lisa , Van Pelt Stephen , Johnson Holly
Published: May 2015

Treating water for injection in an offshore environment has always been challenging. As injection water quality becomes more stringently specified to maximize oil production across a wide range of reservoir geologies, the technical and economic complexity of treating the water dramatically increases. The more stringent treatment can include fine filtration to improve injectivity, specific ion treatment such as sulphate, calcium, magnesium removal to reduce precipitation risks and/or to enable chemical EOR, low salinity treatment for IOR/EOR, and deaeration to very low levels of oxygen to reduce corrosion.

One of the most significant aspects of this added complexity is the inherent weight and footprint of the various unit operations of the water treating facilities that are necessary to achieve rigorous treatment. The weight and footprint of these facilities directly impacts capital costs, which in turn affects the economic viability of greenfield projects and, to an even larger degree, dictates the feasibility of brownfield improvements.

The need for robust, lightweight and compact water treatment technologies for offshore injection has driven innovations in filtration, desalination, softening, sulphate removal, and deaeration. Relative to existing conventional seawater injection facilities composed of media filtration followed by vacuum tower deaeration, the subject innovations achieve an approximate 50 and 90% reduction in footprint and weight, respectively. A number of these technologies have recently undergone pilot and field testing to improve their technology readiness levels prior to full-scale commercialization, and to demonstrate capital costs savings. In addition, operating costs were evaluated. This paper presents the performance results of the pilot and field tests of two of these compact technologies: high production reverse osmosis membranes, and membrane deaeration. In addition to performance results, weight and footprint reductions associated with the technologies are provided to demonstrate the expected savings.
Identifying Chinese Microblog Users With High Suicide Probability Using Internet-Based Profile and Linguistic Features: Classification Model
Authors: Guan Li , Hao Bibo , Cheng Qijin , Yip Paul SF , Zhu Tingshao
Published: May 2015

Background

Traditional offline assessment of suicide probability is time consuming and difficult in convincing at-risk individuals to participate. Identifying individuals with high suicide probability through online social media has an advantage in its efficiency and potential to reach out to hidden individuals, yet little research has been focused on this specific field.

Objective

The objective of this study was to apply two classification models, Simple Logistic Regression (SLR) and Random Forest (RF), to examine the feasibility and effectiveness of identifying high suicide possibility microblog users in China through profile and linguistic features extracted from Internet-based data.

Methods

There were nine hundred and nine Chinese microblog users that completed an Internet survey, and those scoring one SD above the mean of the total Suicide Probability Scale (SPS) score, as well as one SD above the mean in each of the four subscale scores in the participant sample were labeled as high-risk individuals, respectively. Profile and linguistic features were fed into two machine learning algorithms (SLR and RF) to train the model that aims to identify high-risk individuals in general suicide probability and in its four dimensions. Models were trained and then tested by 5-fold cross validation; in which both training set and test set were generated under the stratified random sampling rule from the whole sample. There were three classic performance metrics (Precision, Recall, F1 measure) and a specifically defined metric “Screening Efficiency” that were adopted to evaluate model effectiveness.

Results

Classification performance was generally matched between SLR and RF. Given the best performance of the classification models, we were able to retrieve over 70% of the labeled high-risk individuals in overall suicide probability as well as in the four dimensions. Screening Efficiency of most models varied from 1/4 to 1/2. Precision of the models was generally below 30%.

Conclusions

Individuals in China with high suicide probability are recognizable by profile and text-based information from microblogs. Although there is still much space to improve the performance of classification models in the future, this study may shed light on preliminary screening of risky individuals via machine learning algorithms, which can work side-by-side with expert scrutiny to increase efficiency in large-scale-surveillance of suicide probability from online social media.
Optimization of diode pumped solid state ultraviolet laser dicing of silicon carbide chips using design of experiment methodology
Authors: Savriama Guillaume , Baillet Francis , Barreau Laurent , Boulmer-Leborgne Chantal , Semmar Nadjib
Published: May 2015

This paper investigates the laser micromachining of SiC-4H wafers with an ultraviolet (355 nm) nanosecond source. The design of experiment methodology was used to study the effect of pulse energy, number of passes, defocus, and scanning speed on scribing depth and was modeled with Design Expert® software. Pulse energy and scanning speed were found to have a significant effect on scribe depth (by a factor of 10 compared to defocus), while the effect of the number of passes varied with pulse energy and scanning speed. The model predicted a narrow set of processing parameters to scribe half of the wafer thickness (180/360 μm). A more fundamental study was also conducted in order to validate literature observations on the ablation mechanism. A brief comparison between conventional blade dicing and the laser scribe-break method was performed on a 3 in. diameter wafer. It was discovered that a possible gain of gross die (number of usable chips per wafer) of 7% could be achieved which could provide a useful economic benefit.
Participation of various habitat groups in the flora of spring niches in the Ojców National Park (Southern Poland)
Authors: Sołtys-Lelek Anna , Barabasz-Krasny Beata , Różkowski Jacek
Published: May 2015

The paper presents composition of vascular plant species in spring niches in the Ojców National Park (Southern Poland). 111 species of vascular plants, fourteen mosses, two liverworts and one species of ferns were recorded during the first comprehensive study carried out in 2009 and 2010. Plants occurring in these places showed different degrees of association with spring niches. The largest group was represented by accidental krenophytes (74 species), while spring plants - obligatory krenophytes, constituted only a small part of the local flora (5 species). Meadow species of the Molinio-Arrhenatheretea class and forest species of the Querco-Fagetea class, penetrating niche areas from the adjacent areas, were the dominating ones. Plants of aquatic and spring communities were scarce, due to the predominance of small type karst springs. The diversity of vegetation was significantly influenced by habitat factors such as availability of light, humidity or the amount of organic matter in the soil.
Myoxanthus ortizianus (Orchidaceae), a new species from southern Colombia
Authors: Kolanowska Marta , Szlachetko Dariusz L.
Published: May 2015

With over 3000 species, Colombian orchid flora represents one of the richest in the World. The neotropical subtribe Pleurothallidinae is the most diverse, but it is still a poorly recognized Orchidaceae group and numerous new discoveries within national representatives are described every year. An examination of material collected recently in the Colombian department of Putumayo revealed the existence of a new species of Myoxanthus, named M. ortizianus, which is described, illustrated and placed within an identification key for national species of the nominal section of the subgenus Myoxanthus.
Ophrys apifera Huds. (Orchidaceae), a new orchid species to the flora of Poland
Authors: Osiadacz Barbara , Kręciała Mirosław
Published: May 2015

The paper provides data on the first locality of Ophrys apifera Huds. s. str. in Poland. Information about its geographical distribution and ecological features is given. A newly discovered population, found in a worked-out dolomite quarry near Imielin (Silesian Upland), is described and illustrated, as also, O. apifera is compared with O. insectifera L.