bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect Of Gender And Lifestyle Behaviors On BMI Trends In A Sample Of The First State’s Undergraduate Population
Authors: D’Souza Malcolm J. , Walls Karri-Jo E. , Rojas Christine , Everett Lynn M. , Wentzien Derald E.
Published: February 2016

The 2010 Centers for Disease Control and Prevention (CDC) report indicates that 63.4% of Delaware’s adult population is overweight and 28% is obese. Here, the authors reveal analyses acquired from detailed investigations about the importance of gender, and other lifestyle factors and behaviors on the Body Mass Index (BMI) trends amongst an indiscriminate sample of the Wesley College (Wesley) undergraduate population. A 25-question paper-format survey was distributed to 307 randomly chosen Wesley undergraduates. The accrued qualitative (or categorical) data were transferred to an Excel spreadsheet to construct and observe frequency distributions. A Chi-square test of independence (χ2) was performed between BMI status (normal, overweight, obese) and the following factors: gender, diet plan, adherence to the United States Department of Agriculture (USDA) MyPlate nutrition guide, use of the seasonal flu shot, weekly workout schedule, supplement usage, participation on athletic teams, questioning of label nutritional facts, and the use of added salt in food. A 2-sample proportion test was performed between students who were overweight or obese for the same factors. Also performed were t-tests for mean BMI for those who followed USDA MyPlate guidelines and for those who did not. An analysis of 278 completed surveys show that 29.5% of the Wesley respondents are overweight and 19.8% are obese. The mean BMI for males was statistically higher than the mean BMI for females. The mean BMI for students living on-campus was statistically higher than the mean BMI for students living off-campus. The results also demonstrate that adhering to the USDA dietary recommendations for fruit and dairy can be important factors in reducing the risk of obesity.
The Development And Validation Of The Test Of Astronomy STandards (TOAST)
Authors: Slater Stephanie J.
Published: February 2016

The Test Of Astronomy STandards (TOAST) is a comprehensive assessment instrument designed to measure students general astronomy content knowledge. Built upon the research embedded within a generation of astronomy assessments designed to measure single concepts, the TOAST is appropriate to measure across an entire astronomy course. The TOASTs scientific content represents a consensus of expert opinion about what students should know from three different groups: the American Association for the Advancement of Science, the National Research Council, and the American Astronomical Society. The TOASTs reliability and validity are established by results from Cronbach alpha and classical test theory analyses, a review for construct validity, testing for sensitivity to instruction, and numerous rounds of expert review. As such the TOAST can be considered a valuable tool for classroom instructors and discipline based education researchers in astronomy across a variety of learning environments.
LIBRARY OF THE MINISTRY OF FOREIGN AFFAIRS OF THE PRINCIPALITY OF SERBA IN 1846
Authors: JAGODIĆ MILOŠ
Published: February 2016

This paper presents the content of the library fund (a list of books, periodicals and manuscripts) of the library of the Ministry of Foreign Affairs of the Principality of Serbia in 1846. The fund was quantitatively analyzed according to the languages in which the works were written. The paper also explains when, how and why some titles were acquired for the library. The paper was written on the basis of relevant literature and published and unpublished archival materials of Serbian origin.
FOR READING, WATCHING AND CLAPPING: SARTRE’S “DIRTY HANDSˮ AND HRISTIĆ’S “CLEAN HANDSˮ
Authors: MARIČIĆ GORDAN , MILANOVIĆ MARINA
Published: February 2016

The aim of this paper is to show how and to what extent destinies of two characters two antipodal drama titles are intertwined in the context of human sinning and atonement. We are going to analyze Dirty Hands by Jean-Paul Sartre and Clean Hands by Jovan Hristic. The paper offers interpretations of errors committed by tragic heroes and their comparison with characters from Sophocles' tragedy Oedipus the King. The paper sheds more light on the role and importance of the environment in shaping human guilt, as well as the consequences which this guilt leaves in the lives of the drama characters.
Talking about the limits of legal change: an interview with Marc Galanter
Authors: Galanter Marc , Asperti Maria Cecília , Gabbay Daniela , Salinas Natasha Schmitt Caccia , Alves da Silva Paulo Eduardo
Published: February 2016

Recognized as one of the central figures of the Law & Society and as one of the first editors of the Law & Society Review, Marc Galanter is the author of pioneer and internationally recognized studies on the legal system and patterns of litigation (including "Why the haves come out ahead: Speculations on the Limits of Legal Change", one of the most cited articles in legal literature), lawyers and legal culture, legal institutions and informal regulation, among others. In this interview, Galanter speaks mostly about his academic and professional trajectory, a narrative that is intertwined with the history of tha Law & Society movement itself and with some of the most important developments in American academia since the 60s to the present day. The author also talks about the growth of law firms (described in Tournament of Lawyers) and cultural perceptions currently surrounding lawyers and the legal profession. He discusses the importance of the studies he developed in India for his work, including the famous "Why the haves come out ahead", a piece that is still relevant in the current context.
Notas sobre os juizados de violência doméstica e familiar contra a mulher
Authors: Brandão Cristiane , Lima Clara , Tavares Danielle , Azevedo Juliana , Saueia Renan , Trindade Renato , Carvalho Luiza
Published: February 2016

No âmbito da violência de gênero, as diferenças biológicas apropriadas culturalmente reforçam um estado de acesso desigual a direitos e de submissão a um modelo histórico de aviltamentos recorrentes, que necessitam de um locus de resistência e combate, reivindicado também pelo Poder Judiciário. Assim, com o marco legislativo da Lei 11340/06, criaram-se os Juizados da Violência Doméstica e Familiar contra a Mulher (JVDFM), espaço originalmente concebido para um olhar atento e diferenciado sobre as diversas for- mas de agressão física, moral, psicológica, sexual e patri- monial. A questão que se apresenta agora é, portanto, se a prática de tais órgãos jurisdicionais se coaduna com os objetivos internacionalmente declarados e com os compro- missos assumidos pelo Brasil na implementação de condi- ções para garantir a eficácia de políticas públicas em Direi- tos Humanos. Especificamente, se a assistência judiciária gratuita e de qualidade, através das Defensorias Públicas dos Estados, vem se inserindo conscientemente nesse pro- jeto maior de acesso à justiça, à informação emancipadora, à orientação humanizada e às técnicas de empoderamento capazes de romper o ciclo de violência. O presente texto constitui, então, um mapeamento das práticas institucio- nais, visando a contribuir para o aprimoramento da obten- ção da cidadania plena e reestruturação da nossa esfera pública.
As pesquisas sobre o “sentencing”: disparidade, punição e vocabulários de motivos
Authors: Raupp Mariana
Published: February 2016

O presente artigo propõe-se a traçar um panorama das pesquisas empíricas, estrangeiras e nacionais, so- bre o processo de determinação da pena pela justiça criminal, o “sentencing”. Apontamos a trajetória des- se campo, suas principais conclusões, bem como os pontos cegos de tais estudos. O objetivo é descrever os caminhos desse conjunto de pesquisas de modo a mostrar como os mesmos nos possibilitam refletir sobre a problemática do padrão de funcionamento desigual da justiça criminal apontado não somente por muitos estudos, mas também pelo imaginário so- cial sobre a justiça criminal. A partir do levantamento da literatura sobre o tema, bem como da análise dos principais trabalhos apontados, propomos uma re- qualificação do problema da disparidade das senten- ças criminais, bem como indicamos um novo objeto a ser explorado e, assim, para novas possibilidades de pesquisa empírica sobre o sentencing.
Experiencias en un modelo con material instruccional en línea centrado en el aprendizaje
Authors: Martinez García Mario
Published: February 2016

Por su misma naturaleza, el éxito en la formación universitaria depende de varios actores y factores, cuyo desempeño facilita o inhibe el aprendizaje. La relación pedagógica en los cursos presenciales optimizados que se apoyan en las tecnologías- modelo desarrollado en el Centro Universitario de los Valles (en adelante CU Valles) es afectada por el medio y el contexto de la institución. La calidad de la interacción no solo de los actores centrales del proceso de aprendizaje, estudiantes y profesores, sino también de la misma tecnología, el dispositivo pedagógico utilizado, el apoyo recibido (técnico, académico y social) así como el tiempo dedicado, el lugar y el equipo de trabajo, es decisiva para el buen desarrollo de un curso en línea en este trabajo. La propuesta contempla la implementación de espacios de gestión de la información y del aprendizaje en línea (Material Instruccional en Línea, en adelante MIEL) y la instalación de espacios equipados con equipo de cómputo y con acceso a Internet en las localidades de la región denominados Comunidades de Aprendizaje y Servicios Académicos (en adelante CASAS Universitarias).
Study of Thermal Variations in Wells During Carbon Dioxide Injection
Authors: Lund Halvor , Torsæter Malin , Munkejord Svend Tollak
Published: February 2016

Carbon dioxide (CO2) can be injected into the subsurface to achieve enhanced oil recovery (EOR), possibly with geological CO2 storage. This procedure brings about a set of unique challenges with respect to well construction, operation, and remediation. As compared with normal production, CO2 injection imposes lower temperatures and stronger temperature variations on wells. This is especially prevalent if the injection is not continuous. Downhole-temperature variations will result in expansion or contraction of casings and well-barrier materials, which can cause them to crack or debond at interfaces. To avoid leakage paths through wells, it is therefore important to understand within which temperature intervals it is safe to operate.

In the present paper, we describe a heat-conduction model for calculating heat transfer from the well to the casing, annular seal, and rock formation. These materials have dissimilar thermal properties, and will behave differently with respect to downhole-temperature variations. The model is discretized by use of a finite-volume method developed especially for accurate calculation of heat conducted radially in a well. This allows us to predict temperatures and temperature variations at various locations in and around a given well during CO2 injection.

To validate the numerical model, we compare our simulation results with the time-varying temperatures measured in our laboratory. Good agreement is found between the numerical predictions and the measured data. Simulation results are presented for different combinations of formations and well-barrier materials (cement and alternative types of annular sealants) to display their effect on the well temperature. It is found that, by replacing cement with an annular sealant material with higher thermal conductivity, the temperature difference across the seal can be significantly reduced. A high-conductivity formation such as halite/rock salt can also reduce thermal gradients in the well materials.
Effects of metal ions on biomass and 5-aminolevulinic acid production in Rhodopseudomonas palustris wastewater treatment
Authors: Liu Shuli , Zhang Guangming , Li Jianzheng , Li Xiangkun , Zhang Jie
Published: February 2016

This work investigated the effects of eight metal ions on Rhodopseudomonas palustris growth and 5-aminolevulinic acid (ALA) yield in wastewater treatment. Results show that metal ions (Mg2+ of 15 mmol/L, Fe2+ of 400 μmol/L, Co2+ of 4 μmol/L, Ni2+ of 8 μmol/L and Zn2+ of 4 μmol/L) could effectively improve the chemical oxygen demand (COD) removal, Rp. palustris biomass and ALA yield. The highest ALA yield of 13.1 mg/g-biomass was achieved with Fe2+ of 400 μmol/L. ALA yields were differentially increased under different metal ions in the following order: Fe2+ group > Mg2+ group > Co2+ group = Ni2+ group > Zn2+ group = Mo2+ group > control. Cu2+ and Mn2+ inhibited Rp. palustris growth and ALA production. Mechanism analysis revealed that metal ions changed ALA yields by influencing the activities of ALA synthetase and ALA dehydratase.
Biodegradation of microcystin [Dha7]MC-LR by a novel microcystin-degrading bacterium in an internal airlift loop bioreactor
Authors: Phujomjai Yupin , Somdee Anchana , Somdee Theerasak
Published: February 2016

Cyanobacterial hepatotoxin microcystins are a health problem found in bodies of water in Thailand. Bacteria capable of biodegrading microcystin [Dha7]MC-LR were isolated from the Bueng Nong Khot reservoir in Khon Kaen, Thailand. The bacterium Novosphingobium isolate KKU25s was shown to degrade [Dha7]MC-LR at a concentration of 25 μg l−1 at 30 °C within 24 h. Two intermediate by-products (linearized peptide and tetrapeptide) and a cluster gene (mlrA, mlrB, mlrC and mlrD) that encodes four putative enzymes involved in [Dha7]MC-LR degradation were detected in KKU25s. KKU25s was also shown to form strong biofilms in microtiter plate assays. These assays were carried out in preparation for use of the bacterium in a bioreactor for [Dha7]MC-LR degradation. In an internal airlift loop bioreactor, the biodegradation of [Dha7]MC-LR by the bacterium was established in batch and continuous flow experiments. In the batch experiment, KKU25s degraded [Dha7]MC-LR at a concentration of 25 μg l−1 at 30 °C within 24 h, whereas in the continuous flow experiment, KKU25s degraded the toxin at the same concentration within 36 h. This study demonstrated that this bacterium could potentially be used to remove microcystins from water.
Poultry slaughterhouse wastewater treatment plant for high quality effluent
Authors: Del Nery V. , Damianovic M. H. Z. , Moura R. B. , Pozzi E. , Pires E. C. , Foresti E.
Published: February 2016

This paper assesses a wastewater treatment plant (WWTP) regarding the technology used, as well as organic matter and nutrient removal efficiencies aiming to optimize the treatment processes involved and wastewater reclamation. The WWTP consists of a dissolved air flotation (DAF) system, an upflow anaerobic sludge blanket (UASB) reactor, an aerated-facultative pond (AFP) and a chemical-DAF system. The removal efficiencies of chemical oxygen demand (COD) (97.9 ± 1.0%), biochemical oxygen demand (BOD) (98.6 ± 1.0%) and oil and grease (O&G) (91.1 ± 5.2%) at the WWTP, the nitrogen concentration of 17 ± 11 mgN-NH3 and phosphorus concentration of 1.34 ± 0.93 mgPO4−3/L in the final effluent indicate that the processes used are suitable to comply with discharge standards in water bodies. Nitrification and denitrification tests conducted using biomass collected at three AFP points indicated that nitrification and denitrification could take place in the pond.
Drivers for and against municipal wastewater recycling: a review
Authors: Kunz Nadja C. , Fischer Manuel , Ingold Karin , Hering Janet G.
Published: February 2016

The reclamation, treatment and reuse of municipal wastewater can provide important environmental benefits. In this paper, 25 studies on this topic were reviewed and it was found that there are many (>150) different drivers acting for and against wastewater recycling. To deal with the challenge of comparing studies which entailed different research designs, a framework was developed which allowed the literature to be organized into comparable study contexts. Studies were categorized according to the level of analysis (wastewater recycling scheme, city, water utility, state, country, global) and outcome investigated (development/investment in new schemes, program implementation, percentage of wastewater recycled, percentage of water demand covered by recycled water, multiple outcomes). Findings across comparable case studies were then grouped according to the type (for or against recycling) and category of driver (social, natural, technical, economic, policy or business). The utility of the framework is demonstrated by summarizing the findings from four Australian studies at the city level. The framework offers a unique approach for disentangling the broad range of potential drivers for and against water recycling and to focus on those that seem relevant in specific study contexts. It may offer a valuable starting point for building hypotheses in future work.
Impact of fine mesh sieve primary treatment on nitrogen removal in moving bed biofilm reactors
Authors: Rusten B. , Razafimanantsoa V. A. , Andriamiarinjaka M. A. , Otis C. L. , Sahu A. K. , Bilstad T.
Published: February 2016

The purpose of this project was to investigate the effect of selective particle removal during primary treatment on nitrogen removal in moving bed biofilm reactors (MBBRs). Two small MBBR pilot plants were operated in parallel, where one train treated 2 mm screened municipal wastewater and the other train treated wastewater that had passed through a Salsnes Filter SF1000 rotating belt sieve (RBS) with a 33 µs sieve cloth. The SF1000 was operated without a filter mat on the belt. The tests confirmed that, for the wastewater characteristics at the test plant, Salsnes Filter primary treatment with a 33 µs RBS and no filter mat produced a primary effluent that was close to optimum. Removal of organic matter with the 33 µs sieve had no negative effect on the denitrification process. Nitrification rates improved by 10–15% in the train with 33 µs RBS primary treatment. Mass balance calculations showed that without RBS primary treatment, the oxygen demand in the biological system was 36% higher. Other studies have shown that the sludge produced by RBS primary treatment is beneficial for biogas production and will also significantly improve sludge dewatering of the combined primary and biological sludge.
Tylosin effect on methanogenesis in an anaerobic biomass from swine wastewater treatment
Authors: García-Sánchez Liliana , Garzón-Zúñiga Marco Antonio , Buelna Gerardo , Estrada-Arriaga Edson Baltazar
Published: February 2016

The effect of different concentrations of tylosin on methane production was investigated: first methanogenesis in a biomass without contact with the antibiotic, and later the ability of the sludge to adapt to increasing concentrations of tylosin. Results showed that, for biomass that had no contact with the antibiotic, the presence of tylosin inhibits the generation of methane even at concentrations as small as 0.01 mg L−1, and samples at concentrations above 0.5 mg L−1 produced practically no methane, whereas, in the digesters acclimated in the presence of tylosin at a concentration of 0.01 to 0.065 mg L−1, methanogenesis is not inhibited in the presence of antibiotic and the generation of methane is improved. This behaviour suggests the microorganisms have developed not only resistance to the antibiotic but also an ability to metabolize it.
Comparison of the efficacy of prednisone and cyclosporine for treatment of dogs with primary immune-mediated polyarthritis
Authors: Rhoades Amy C. , Vernau William , Kass Philip H. , Herrera Melissa A. , Sykes Jane E.
Published: February 2016

OBJECTIVE To compare efficacy between cyclosporine and prednisone for treatment of primary immune-mediated polyarthritis (IMPA) in dogs.

DESIGN Randomized controlled clinical trial.

ANIMALS 20 client-owned dogs with primary IMPA.

PROCEDURES Dogs were randomly assigned to receive prednisone (starting at 1 mg/kg [0.45 mg/lb], PO, q 12 h; n = 10) or cyclosporine (5 mg/kg [2.3 mg/lb], PO, q 12 h; 10) for 90 days. Cyclosporine-treated dogs also received carprofen, tramadol, or both for the first 7 days for analgesia. Data collection, physical examination, and cytologic analysis of synovial fluid samples were performed on days 0, 14, 45, and 90. Trough whole blood cyclosporine concentrations were determined on days 7 to 17 for cyclosporine-treated dogs. Treatment failure was defined as lack of clinical improvement by day 14, lack of cytologic improvement by day 45, or need to change treatment because of adverse effects.

RESULTS Treatment was successful for 7 prednisone-treated dogs and 7 cyclosporine-treated dogs. Absence of synovial fluid cytologic abnormalities on day 45 was identified for 5 prednisone-treated dogs and 8 cyclosporine-treated dogs. Prednisone-treated dogs were more likely to develop polyuria, polydipsia, and polyphagia than were cyclosporine-treated dogs. Opportunistic infections (ie, demodicosis or Erysipelothrix bacteremia) were identified in 2 cyclosporine-treated dogs and 0 prednisone-treated dogs, and diarrhea developed in 1 cyclosporine-treated dog, requiring treatment discontinuation.

CONCLUSIONS AND CLINICAL RELEVANCE Although the number of dogs evaluated was small, limiting generalizability, results of this study suggested that cyclosporine offers promise as a suitable alternative to prednisone for treatment of IMPA in dogs.
Ventricular pneumocephalus, cervical subarachnoid pneumorrhachis, and meningoencephalitis in a dog following rhinotomy for chronic fungal rhinitis
Authors: Launcelott Zoë A. , Palmisano Mathew P. , Stefanacci Joseph D. , Whitney Beth L.
Published: February 2016

CASE DESCRIPTION A 5-year-old 35.8-kg (78.8-lb) neutered male Labrador Retriever was evaluated for chronic nasal discharge associated with a fungal infection. The dog had previously been prescribed antimicrobials and antifungal treatment, but owner compliance was lacking.

CLINICAL FINDINGS Bilateral mucopurulent nasal discharge, mild ulceration of the left nasal commissure, and hyperkeratosis of the dorsal nasal planum were present. Computed tomography revealed destruction of the intranasal structures, focal lysis of the cribriform plate, and invasion of a soft-tissue mass into the frontal cortex. Rhinoscopy revealed a large pale mass in the caudal aspect of the right nasal passage; a biopsy sample was consistent with Aspergillus sp on histologic evaluation.

TREATMENT AND OUTCOME Initial treatment included medical management with an antifungal agent. Approximately 3 months later, a large fungal granuloma in the right frontal sinus was removed and debridement was performed via dorsal rhinotomy. One month after surgery, the dog was evaluated for signs of cervical pain and altered mentation. An MRI and CSF analysis were performed; diagnoses of ventricular pneumocephalus, subarachnoid pneumorrhachis, and meningoencephalitis were made. Management included oxygen therapy and administration of antimicrobials, analgesics, and antifungal medications. On follow-up 9 months after initial evaluation, neurologic deficits were reportedly resolved, and the dog was doing well.

CONCLUSIONS AND CLINICAL RELEVANCE This report emphasizes the importance of prompt, appropriate treatment of fungal rhinitis in dogs. Although rare, pneumocephalus and pneumorrhachis should be included as differential diagnoses for neurologic signs following treatment for this condition. In this dog, the complications were not considered severe and improved over time with supportive care.
Identification of Metastatic Lesions in a Patient With Low Back Pain Following a Motor Vehicle Collision
Authors: Plass Lindsey M. , McGee Terrence G. , Elliott James M.
Published: February 2016

A 58-year-old man was referred to physical therapy with a primary complaint of intermittent low back pain (LBP) 2 weeks after being in a motor vehicle collision. The absence of red flags justified the initiation of treatment, but when symptoms of unrelenting LBP emerged, he was referred to his primary care physician with a request for further medical workup. Before further imaging work-up was performed, the patient presented to the emergency room with a urinary complaint; this, in combination with unrelenting LBP, prompted further imaging follow-up. Lumbar/thoracic spine magnetic resonance imaging revealed multiple compression fractures and diffuse bone marrow heterogeneity consistent with a malignant infiltrative marrow process. The patient underwent additional laboratory testing and a bone marrow aspirate and biopsy that confirmed the diagnosis of multiple myeloma.

J Orthop Sports Phys Ther 2016;46(2):124. doi:10.2519/jospt.2016.0403
Surfactant-Enhanced Stimulation Technology for Polymer-Injection Wells
Authors: Wang Yan , Wang Demin , Sun Zhi , Zhao Song , Wang Gang , He Guanzhong , Zhang Jian , Xu Wenqin , Yu Yongbo
Published: February 2016

After polymer flooding in Daqing Oil Field, the injection pressure in the flooded areas has increased. The injection pressure of one third of the polymer-injection wells is near to its fracturing pressure, and many polymer injection wells have to lower its injection rate. Since the effective period of fracturing in polymer injection wells is less than 3 months, a new polymer injection well stimulation technology was in great need to be developed.

The system does not need alkali, and under formation conditions, the interfacial tension remains ultra-low for at least 28 days. A series of lab tests shows that to first remove the polymer adsorbed on the rock, a slug containing an oxidant needs to be injected before the surfactant slug. The surfactant slug lowers the residual oil concentration, increases the relative permeability to water and adsorbs on the rock near the well bore, preventing polymer to adsorb on the rock in the subsequent stage of polymer flooding. Lab tests shows that adopting a flooding process of subsequently injecting an oxidant slug, then a surfactant slug and last followed by polymer flooding obtains the best results (the permeability to polymer fluid is increased about 120%).

Introduction

At present, the starting pressure (e.g., the pressure at which water starts to be injected into the well) of polymer-injection wells is commonly high and injection rate is relative insufficient in Daqing Oil Field. The high starting pressure and injection pressure of the polymer injection wells greatly influence the development results of the oil field, these are mainly reflected in the following aspects:The starting pressure is too high so that an effective pressure differential cannot be set up between production and injection wells, resulting in poor developing result.The high injection pressure causes an increase in the number of casing damage wells.The injection pressure is too high; therefore the injection solution cannot advance evenly into the wells.In order to maintain the injection rate of medium and low permeability layers developed by polymer flooding, the well spacing needs to be reduced and the development cost is increased.

Therefore, it is very important to study technology that can effectively reduce the starting pressure and injection pressure of polymer-injection wells.
GTL Plus Power Generation: The Optimal Alternative for Natural Gas Exploitation in Nigeria
Authors: Adegoke Adesola Ayodeji , Barrufet Maria A. , Ehlig-Economides Christine A.
Published: February 2016

Nigeria has an estimated 187 trillion cubic feet (Tcf) of proven natural gas reserves, which is about 4% of the world proven reserves. About 60% of this reserve is associated gas and over 50% is either being flared or re-injected for enhanced oil recovery. The government just introduced a policy to stop gas flaring by 2008, hence energy companies have to develop new strategies of utilizing the stranded gas reserves especially the associated gas. Liquefied Natural Gas (LNG) is the country's cutting-edge technology in the exploitation of stranded gas reserves. With a projected increase in world market share to 13%; the country ranks as one of the highest producers of LNG in the world. However, while LNG accounts for 27% of all traded natural gas the hydrocarbons used for LNG are dwarfed by the size of liquid middle distillates such as diesel and naptha. Furthermore, LNG as traded today is strongly driven by long-term and high risk contractual agreements.

A re-visited way for natural gas exploitation is the Gas to Liquids (GTL) technology, with most end products being useful in transportation fuels and base chemical feedstock. An often overlooked issue, which could be decisive in Nigeria, is the use of GTL ancillary products with no commercial value. The underlying objective of this study is to build a business case for GTL as an alternative marketing strategy to LNG for stranded gas reserves in Nigeria, with the utilization of by-product streams for commercial power generation.

This analysis will present a robust and economic solution to natural gas exploitation in terms of the technological and environmental factors scalable to supply and demand constraints. Justifying the technology and economics involved in the utilization of the by-product streams for commercial power generation may possibly increase the net revenue and profitability of the GTL projects. This technology may be transferable to other GTL projects in the world wherever there is a market for power generation.

Introduction

The World Bank estimates Nigeria alone accounts for 12.5% of the world's annual gas flared though the Nigerian government has enacted a policy of "Zero-Gas Flare" by 2008. This translates to about 800 Bcf of natural gas flared annually. Hence, energy companies have to develop strategies to utilize the "stranded" gas produced.
A Novel Ultrasonic Cased-Hole Imager for Enhanced Cement Evaluation
Authors: van Kuijk Robert , Zeroug Smaine , Froelich Benoit , Allouche Michael , Bose Sandip , Miller Douglas , Le Calvez Jean-Luc , Schoepf Virginie , Pagnin Andrea
Published: February 2016

Current acoustic (sonic and ultrasonic) techniques for cement evaluation have proved to be limited in providing unambiguous answers to the zonal isolation issue. This is especially true in lightweight cements where they often fail to differentiate cement from mud. Also, as far as imaging of the cement sheath is concerned, ultrasonic pulse-echo tools fail to image beyond the cemented region adjacent to the casing, thus providing limited diagnosis of the annulus. A new ultrasonic imaging tool has been developed to address these limitations.

The new imager combines the classical pulse-echo technique with a new ultrasonic technique that provides temporally compact echoes arising from propagation along the casing and also reflections at the cement-formation interface. Processing these signals yields unprecedented characterization of the cased hole environment in terms of the nature and acoustic velocity of the material filling the annulus between casing and formation, the material immediately behind casing, the position of the casing within the hole, and the geometrical shape of the hole.

Different wells cemented with conventional and light cements were logged with the new experimental tool. The results demonstrate enhanced cement evaluation for both cement types and significant reduction in the uncertainty in making a squeeze or no-squeeze decision.

Introduction

Cement evaluation logging tools have been used successfully for many years to evaluate casing and cement conditions. These tools, which use sonic or ultrasonic1 techniques, are designed for conventional steel casing and cements. The sonic tools, commonly known as Cement Bond Log or CBL, operate at frequencies of about 20 kHz and measure the amplitude or the attenuation of a wave traveling along the casing. The wave loses energy mainly though shear coupling to the surrounding cement, so that well-bonded solid cement attenuates more quickly than a fluid. Due to the low frequency, the CBL logs made with these tools lack azimuthal resolution, which makes it difficult to distinguish channeling from poor cement properties.
Obtaining Permeability From Seismic Data - A New Breakthrough in Carbonate Reservoir Modelling
Authors: Gartner G.L. Bracco , Wagner P.D. , Baechle G.T. , Sun Y.-F. , Weger R. , Eberli G.P. , Asyee W. , Hillgartner H. , Van der Kolk K. , Leguijt J. , Nasser M.R. , Massaferro J.L.
Published: February 2016

This reference is for an abstract only. A full paper was not submitted for this conference.

Shell's Carbonate Team has been developing a method in which post-stackseismic can be used to estimate average interval matrix permeability incarbonates. The foundation of the technique is a new model, which describes quantitative relationships between sonic velocity, porosity and permeability. This model relates a pore shape factor from the poro-elasticity theory with permeability from lab measurements. This pore shape factor describes the 3Dpore structure and can be extracted from inverted post-stack seismic data. Additionally, this factor relates to pore connectivity and, therefore, to permeability.

After the concept was tested and successfully proven on plug scale, the first implementation focused on a large carbonate field in the Middle East. This accumulation had all the ingredients to perform a full field test of the concept - good thickness for multiple seismic reflections, matrix-dominated permeability, single mineralogy (calcite), superb seismic data and enough wells with good compressional and shear sonic logs.

Introducing pore structures in the characterisation of carbonate reservoirs from acoustic data helps resolve the ambiguity in porosity/permeability prediction. In the test case, we have demonstrated that: the new rock property prediction is much more accurate than properties predicted by commercial inversion packages,pore structure can be extracted from 3- Dpost-stack seismic,a permeability indicator can be estimated from inverted seismic anda permeability indicator volume proved to produce a superior history match against a permeability model constructed from extensive welldata
Application of Wireline Formation Tester (Openhole and Cased-Hole) Sampling Techniques for Estimation of Nonhydrocarbon Gas Content of Khuff Reservoir Fluids in the North Field, Qatar
Authors: Al-Mohsin A. , Tariq S. , Haq S.A.
Published: February 2016

Qatar's North Field is the largest non-associated gas field in the world. The North Field is being developed primarily to supply feedstock gas for a number of LNG (Liquefied Natural Gas) and GTL (Gas-to-Liquid) plants. Accurate determination of the amount of H2S and CO2 in the feedstock gas is critical for the proper design of the LNG and GTL plants. Due to long lead time required for the design and the construction of these processing plants, it is necessary to establish the feedstock gas specifications as early as possible during the FEED (Front End Engineering & Design) process. Moreover, once the plant design specifications are set, early estimation of H2S and CO2 content of Khuff reservoirs at the development well locations is necessary to design a well completion scheme to meet the plant design specification for the feedstock gas.

In 2003, RasGas decided to evaluate several sampling techniques for early estimation of the non-hydrocarbon (NHCG) gas content from Khuff reservoirs. After a thorough study of available options for making reliable measurements of H2S and CO2 content of reservoir fluids using down hole tools, it was decided to test Wireline Formation Testers (WFT), both open-hole (OH-WFT) and cased-hole (CH-WFT) tools, in an appraisal well as a "proof of concept" of these technologies for estimation of H2S and CO2 contents. The results from both OH-WFT and CH-WFT techniques were compared with normal DST surface recombined samples obtained from the same well.

In this paper, the following aspects of OH-WFT and CH-WFT sampling techniques for determining H2S and CO2 contents are discussed and the results/analysis presented:Optimal tool / Sampling bottles / flow line configuration for reducing H2S scavenging effect.Comparative analysis on a relative basis between OH-WFT & CH-WFT samples, both on-site and in laboratory.Evaluation of OH-WFT, CH-WFT and DST sample compositional results on a relative basis.Conclusions / Recommendations.
Assessment of Interwell Communication in the Carbonate Al Khalij Oil Field Using Isotope Ratio Water Sample Analysis
Authors: Danquigny Jacques Albert , Matthews James , Noman Rashed , Mohsen Abdulla
Published: February 2016

Assessment of communication between water injectors and oil producers is a key issue to implement improved oil recovery programs. This paper presents an innovative use of isotope ratio water sample analysis to characterize injector-producer communication and intra-reservoir connectivity in a mature field.

Salt analysis is the standard approach to differentiate injection water from formation water, and assess water injection sweeping efficiency. This requires the brines to have different compositions. However, interactions from the mixing of the two waters or with the formation can prevent reliable information from being obtained from such analyses.

The isotope ratios of water samples are not sensitive to these interactions. This technique is often used in exploration to assess inter-reservoir connectivity at the delineation stage. This paper shows the successful application of isotope ratio analysis to the complex Mishrif carbonate reservoir of the mature Al Khalij field located offshore Qatar. The field has been in production since 1997 and water is injected from a shallow aquifer, while coning from a bottom aquifer is suspected.

In this field, Strontium, Oxygen and Deuterium isotope ratio measurements were carried out on samples collected from a number of wells across the field. This technique enabled us to assess the percentage of injection water produced at each well, and assist in optimizing water injection management.

Introduction

Interwell tracing and water injection

Water injection is the most common secondary recovery process. Injection optimization requires a correct assessment of interwell communication. This is all the more valid in carbonate reservoirs which are commonly fractured; the dynamic impact is usually difficult to assess with static data such as wellbore images or seismic. Production logging or interwell tracing are among the most applied and valuable monitoring techniques to evaluate this impact.
Shell's LNG Technology for 7 - 10 Mtpa LNG Trains
Authors: Buijs K. , Pek B. , Nagelvoort R.
Published: February 2016

The rapid market growth in LNG and the development of large gas reserves such as the North Field of Qatar demand another step-change in the capacity of LNG trains, as lowest unit cost continues to be a key value driver.

With the standard Propane Mixed Refrigerant (C3/MR) technology, capacities up to 5 Mtpa can be achieved with two GE Frame 7 gas turbines as drivers. For higher LNG capacities new configurations are required. Shell has developed designs for both mechanically driven and electrically driven large LNG trains, featuring low cost and low emissions. The choice is determined by project specific considerations.

The Shell Parallel Mixed Refrigerant process consists of a single pre-cool cycle followed by two parallel liquefaction cycles. For pre-cooling either propane or a mixed refrigerant, like in Shell's Double Mixed Refrigerant Process (DMR), is used. With three well proven GE Frame 7 gas turbines, 8 Mtpa of LNG production is achieved. With GE Frame 9 or Siemens V84.2 gas turbines, the LNG capacity increases to 10 Mtpa; these gas turbines are still novel drivers for the LNG industry but are already used as mechanical drivers in other processes.

The Shell Parallel Mixed Refrigerant Process for large LNG trains has a number of appealing advantages:Robustness through the application of well-proven equipment without scale-up of equipment.High reliability and availability by parallel line-up of the liquefaction cycle. For example, if one of the liquefaction cycles trips, LNG production is designed to continue at 60% of train capacity.The optimal power balance between the two liquefaction cycles (1:2) results in a high efficiency.

The application of Shell's electrically driven DMR process is also very attractive. This concept is based on a parallel line-up of the refrigerant compressors around a common set of cryogenic spoolwound exchangers. Electric motors of 65 MW have already been constructed for LNG service. In combination with Shell's DMR technology an LNG production capacity of 8 Mtpa can be achieved. The power station is driven by gas turbines.
Sustained Development in the Pearl GTL Treating Design
Authors: Grootjans Henk
Published: February 2016

Feed gas for Shell's Gas to Liquids (GTL) project in Qatar is supplied from the North Field. Before this sour gas can be processed in the GTL plant it has to be rigorously treated to meet the stringent contaminant specifications for a modern GTL process.

The feed gas contains a wide range of contaminants, including H2S, CO2, several mercaptan species and COS. Treating this gas to specification requires a series of treating processes. These processes have to be selected and integrated to provide a treating complex that is not only cost effective, but also will remove contaminants in an environmental friendly way.

Sustained development has been one of the key elements in the process selection of the Pearl GTL treating units, and this can be clearly seen from the final line-up that has been selected. For the main acid gas removal unit a selective amine process has been chosen. By removing mercaptans in a molecular sieve process, rather than by using a physical solvent the co-absorption of hydrocarbons has been minimized. This improves hydrocarbon efficiency and thus reduces CO2 emissions from burning these hydrocarbons in the sulfur recovery unit is. All sulfur containing streams from the treating units are routed to the sulfur recovery unit, which has been fitted with a special burner arrangement and an integrated tail gas treating unit to maximize the sulfur recovery efficiency over a wide range of feed gas compositions.

The paper provides details on the process selection process taken by Shell Global Solutions, showing the process options that were available and the environmental benefits that were achieved.

Introduction

The Pearl GTL project will be located in Ras Laffan, Qatar and will consist of two trains, which together will produce 140,000 barrels of middle distillates and base oils from natural gas using Shell GTL technology. In addition the plant will produce significant quantities of condensate and LPG. The Pearl GTL project has completed the FEED design phase. Start-up of the project is targeted for late 2009.
Khuff Gas Condensate Development
Authors: Whitson C.H. , Kuntadi A.
Published: February 2016

This paper addresses some key reservoir and production issues related to gas and condensate recovery from Khuff reservoirs in the Middle East – namely Ghawar Khuff, North Field and South Pars. These fields represent somewhere between 1,000 and 2,000 Tcf initial gas in place, with 30 to 70 billion barrels of condensate in place. We apply engineering methods and reservoir simulation to quantify the expected performance of Khuff gas condensate fields for a realistic range of geologic description, petrophysical and fluid properties, and production facilities based on published information.

We review key data for reservoir and production design, summarizing the impact of geologic zonation, areal and vertical communication, mean permeability and its variation, relative permeability, water encroachment, and fluid composition on field performance. Because most commercial development projects involving gas sales export are based on delivery contract quotas (DCQs) of 1–1.5 bcf/D for up to 25 years, well-average plateau length and rate-time is used as a primary measure of performance.

We try to describe the interplay of reservoir and production-facilities performance on overall design of field deliverability and total well requirements. Other production issues not considered in our work but with significant impact on Khuff development strategy include gathering system design, rate metering, platform vs. onshore processing, and single-phase vs two-phase pipeline flow. Economics are not considered in our evaluation.

We estimate deliverability impairment from condensate blockage using relative permeability models that reflect the impact of velocity (capillary number improvement and inertial effect). The velocity effect is particularly important in Khuff wells because of the high-k, low-h layers with unusually-high flow velocities and convergent flow.

Layer vertical and areal connectivity can have a profound effect on water encroachment. When sufficient lateral continuity exists, even small aquifers can result in rapid water encroachment through thin, high-permeability zones. This has been studied and is shown to have a lesser effect in Khuff reservoirs.
Physics-Based Well Design - Engineering the Well for Production
Authors: Kline William E. , Dale Bruce A. , Kumar Rahul , Clingman Scott , Asmann Marcus , Rosenbaum Darren F.
Published: February 2016

Ensuring long-term well integrity and optimum completion performance is important for the economic development of any field. However, as fields are now developed with fewer wells and in more technically challenging environments, new technologies are required to deliver mechanically robust and reliable wells that can be operated at the high rates required to meet today's aggressive production targets. Unfortunately, in this environment, our industry can no longer rely on historical industry practices that are based on generalized principles, aggregate historical data, anecdotal evidence, and simplified analytical models, because the inherent inaccuracy of these types of analyses requires excessive use of a significant safety factor between the planned production rates and the actual deliverability limit of the well.

To address this challenge, ExxonMobil has developed unique, physics-based, completion design and well performance modeling capabilities that are applied during both well planning and production phases to optimize overall well performance.

For example, the ability to accurately model the coupled-physics effects of reservoir compaction, sand production, subsurface shear/slip, completion tubular deformations, and various near-well flow impairment effects enables targeted management of critical mechanical integrity and flow capacity issues. More importantly, these models have provided predictive technologies that have resulted in significant business advantage, as ExxonMobil has developed the capability to quantitatively transform these highly complex issues into well defined, and easily applied "technical limits," which establish the boundaries between conservative, optimum, and potentially detrimental well design and production operations. Practical application has been facilitated by defining these limits in simple terms, including reservoir depletion and/or well drawdown.

The incorporation of advanced physics and the corresponding coupled-physics interactions into modeling, simulation and decision-making processes, enables accurate, definition of well performance technical limits and the ability to produce a well right up to these limits. These physics-based production guidance tools provide the technical basis from well design to choke management, enabling more aggressive production with confidence, without risk of failing or impairing wells unnecessarily.