bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of Liquid Crystal on Gel Formation Rate of Viscoelastic Surfactant for Hydraulic Fracturing
Authors: Yang Jiang , Lu Yongjun , Guan Baoshan , Cui Weixiang , Qiu Xiaohui , Yang Zhen , Chen Junbin , Yang Guanke 
Published: April 2013

Abstract
The viscoelastic surfactant (VES) as low formation damage fluids can be used in hydraulic fracturing and acidizing of low permeability oil and gas reservoir. The physical association and entanglement of wormlike micelle in diluted range gives viscoelastic properties, which gives similar properties as polymer. Compared with traditional polymer fluids, VES fluids used few additives and were easy to prepare in the wellsite. However, some VES fluids could take a long time to dissolve and build up viscosity in the field operation when it is diluted from concentrate. Amphoteric VES is hereby studied to understand the cause of such problems. The phase behavior of the surfactant-solvent-water was investigated. It was found that a three phase range consisted of liquid crystal gel was passed during diluting process. It consisted of a hexagonal liquid crystal phase. Hexagonal liquid crystal is highly viscose rod-like aggregate, it took longer time, up to several hours, to dissolve to form VES in the lab and field test. A cosurfactant was added to concentrate to increase the dissolve rate. Transient hexagonal liquid crystal gel is transformed to lamellar liquid crystal gel upon addition of co-surfactant. The microstructure of liquid crystal is confirmed by cross-polarizer microscope and small angle X-ray diffraction. The lamellar liquid crystal with multi-layer structure has low viscosity. It forms VES and builds up in viscosity within 2 minutes in the lab tested, and can form VES on-the-fly in field blending. Addition of cosurfactant didn't change performance of the prepared fluid at high temperature. Hence, the liquid crystal phase structure is the critical factor for dissolving rate of VES concentrate in the field operation.
Energy Policy Analysis and Uncertainty
Authors: Blaskovich Frank 
Published: April 2013

Abstract
Developing energy policies that work well is a difficult task. Many factors can affect the results for all interested parties, including the government and energy producers. Good policies require an appreciation for the interactions among oilfield development and operations, costs and prices, government taxes and regulations, infrastructure failures, and many other factors. We built a system dynamics model of an oil province to explore how government tax policy might be impacted by uncertainties in field operations as well as parameters outside the normal purview of most model studies. We tried to identify those uncertain parameters that might have the largest impacts on energy policies for both the government and operators. The government and producer typically want the maximum possible profitability. However, the best solution (e.g., maximum net present value) is seldom, if ever, the same for everyone. We developed an approach using regret analysis to finding flexible and resilient tax policies, in spite of uncertainties, that would provide all parties with fair, profitable solutions – even though none might achieve their maximum goals.
Our model can quickly run thousands of scenarios and can also be used as a training simulator. This makes our approach very useful and flexible for government agencies, energy companies and both groups working together to find solutions that might otherwise not be explored.
We believe that significantly better policy solutions may be found using our approach than more traditional "linear" techniques in which simulation model results are subsequently used to perform economics analysis in a stepwise manner. Instead, we combine the important aspect of both plus other non-traditional factors to achieve solutions that depend on the interaction of the most important parameters.
We believe that this approach represents a useful new paradigm compared to techniques that focus on individual components and/or exclude non-traditional, but important factors. We emphasize the inter-relationships among those factors that greatly affect policies for the mutual benefit of all parties in ways that are unique compared to other approaches that have previously been reported in the petroleum literature.
Global Model for Failure Prediction for Rod Pump Artificial Lift Systems
Authors: Liu Yintao , Yao Ke-Thia , Raghavenda Cauligi S. , Wu Anqi , Guo Dong , Zheng Jingwen , Olabinjo Lanre , Balogun Oluwafemi , Ershaghi Iraj 
Published: April 2013

Abstract
This paper presents a new generalized global model approach for failure prediction for rod pumps. By embedding domain knowledge into an Expectation Maximization clustering algorithm, the proposed global model is able to statistically recognize pre-failure and failure patterns from normal patterns during the training stage. Compared with previous field-specific models, the enriched training set for the global model learns from much larger scale of normal and failure examples from all fields with which a generalized Support Vector Machine (SVM) is trained and is able to predict failures for all fields. The data set for this paper is taken from five real-world assets using rod pump artificial lift systems which contain nearly 2,000 rod pumps. The results show that the global model of failure prediction is capable of capturing future rod pump and tubing failures that produce acceptable precision and recall. The resulting global model is scalable and can be used for predicting failures for proactive maintenance to reduce lost oil production. Results from our case studies with multiple fields data show that precision and recall are better than 65% with this global model.
Our prior work [1] used machine learning techniques to generate high quality failure prediction models with good accuracy. However, these efforts suffer from two major drawbacks. First, this used machine learning techniques that require labeled datasets for training the model. Generating these labeled datasets is human-intensive and time-consuming. Second, this model is field-specific which is only applicable to the specific field from which the labeled dataset is derived. These field-specific models generally perform poorly on other fields because of the differences in the data characteristic caused by field geology, operational procedure, etc. Moreover, these models have to be maintained independently, which accordingly raises nontrivial maintenance costs.
Dynamic Soltion Approach to the Inclination and Amizuth of Bottom Rotating Drill String
Authors: Xue Qi-Long , Wang Rui-He , Huang Lei-Lei , Sun Feng 
Published: April 2013

Abstract
In the oil drilling process, measurement-while-drilling (MWD) system is usually used to provide real-time monitoring of the position and orientation of the bottom hole. Particularly, in rotary steerable drilling technology and application, how to accurately measure the spatial attitude (inclination, azimuth, tool face) of the bottom drilling tool in real time while the drill string rotating is a challenging problem. Current MWD surveying is performed along the well path at stationary survey stations, because of that the bottom drilling tool shows complex characteristics while rotating due to combined effect of their randomly nonlinear moving state, such as vertical vibration, horizontal vibration, and stick-slip. The effects of complex characteristics cause sensors to generate a great dynamic error which will accumulate gradually during attitude resolving, so ultimately measuring spatial attitude deviates seriously from the true value.
This is a huge challenge for signal processing. In this paper, a set of "strap-down" measurement system was developed, the triaxial accelerometer and triaxial fluxgate were installed near the bit, and real-time well deviation and azimuth can been measured even when the drill string was rotating. However, according to the drilling field tests, playback analysis on storage data of the underground measurement indicates that drill string vibration is the main reason for measurement errors.
So this paper proposed dynamic solution approach to the bottom of the rotating drill string attitude. By setting a time window, the real-time measurement of the accelerometer and the flux gate signal are processed and analyzed, the movement patterns of the rotary drilling tool at the bottom were judged within the time window.utilizing stick-slip vibration to improve measurement accuracy, reducing the impact of vibration on the measurement results at the same time. Although the stick-slip vibration should be avoided point of view the life of the drill string, we can still take advantage of it because of it cannot be avoided entirely.
A continuous measurement while drilling system was developed and a large number of field test data were also analyzed. Simulation results in Matlab showed that recommended dynamic survey approach could effectively enhance measurement precision, and deduce effect of vibration on resolve results.
SDPF: A Framework for Online, Real-time Cleansing of Upstream Operating Data
Authors: Banaei-Kashani Farnoush , Asghari Mohammad , Mofrad Mahdi Rahmani , Shahabi Cyrus , Brenskelle Lisa 
Published: April 2013

Abstract
Since the quality of the raw upstream operating data can be poor in many instances (due to errors, incompleteness, and inconsistency), there is often an urgent need to cleanse the data in real time before using the data for process and business decision-making. In this paper, we present the design and development of an integrated data cleansing framework that can address a variety of upstream operating data quality issues systematically. Our proposed framework, dubbed SDPF (short for Scalable Data Processing Framework), benefits from the following features: Online/Real-time Data Cleansing, Scalability, Configurability, Reusability, and Comprehensiveness. We have tested and verified the performance of our data cleansing system with both real upstream operating data collected and synthetic data.
Characterization and Analysis on Petrophysical Parameters of a Marine Shale Gas Reservoir
Authors: Wei Chenji , Qin Guan , Guo Wei , Yan Bicheng , Killough John E. , Wang Hongyan , Liu Honglin 
Published: April 2013

Abstract
Shale gas remains one of the hottest topics in the petroleum industry. Petrophysical characterization is an important step for a new shale gas play to better understand the geology of the formation, and it provides vital data to optimize production plan and stimulation design. However, there is little research on correlations between petrophysical parameters for shale gas reservoirs.
The methodologies involved in this study include experimental study, outcrop observation, statistical analysis, and numerical modeling. The Longmaxi shale formation, which is an emerging Lower Silurian marine shale play in China with huge potential according to preliminary explorations, was characterized petrophysically in detail, and research on correlations between different petrophysical parameters was conducted. More than 100 ft core samples were collected from target layers for experiments. Also, the reservoir properties of the Longmaxi shale were compared with those of shale gas plays in the United States, such as the Barnett and Marcellus. Furthermore, based on a robust in-house simulator exclusively for shale gas, a reservoir model was developed by integration of those available petrophysical data to evaluate the key production drivers for typical shale gas reservoirs.
After integrating results from all these methodologies and technologies, total organic content (TOC), vitrinite reflectance (Ro), porosity, permeability, mineralogy, and gas content were obtained. Then, analysis was carefully conducted, and some interesting observations were found, such as an intimate correlation between the clay content and desorbed gas content. Additionally, both similarities and differences between petrophysical properties were concluded from comparison between the Longmaxi Shale and shale gas plays in the US. Moreover, Simulation results quantified the effects of natural fractures and desorption for the production performance.
This study provides a methodology for understanding and characterizing other shale plays. In addition, it offers detailed evidence to support engineers and geologists for understanding the geology and optimizing production plan on the marine shale.
Development and Application of Near-Well Multiphase Flow Upscaling for Forecasting of Heavy Oil Primary Production
Authors: Li Hangyu , Chen Yuguang , Rojas Danny , Kumar Mridul 
Published: April 2013

Abstract
Near-well effects can have a strong impact on reservoir flow. Current reservoir modeling practice often uses coarse-scale flow simulation models, which may lead to biased results, compared with fine-scale models. In this work, we extend and apply a recently developed near-well multiphase flow upscaling technique to the coarse-scale simulation of heavy-oil primary production. For heavy oils, oil viscosity is a strong function of pressure when the pressure is below the bubble point. Therefore, the upscaled mobility functions (from near-well multiphase upscaling) depend on both pressure and saturation, which cannot be directly input to general purpose reservoir simulators. This is very different than the upscaled mobility functions for typical black-oil fluids, in which oil viscosity does not vary significantly with pressure. Accordingly, the upscaled mobility functions are often equivalent to upscaled relative permeabilities (as functions of saturation only). In this work, we develop two procedures to derive either the upscaled relative permeability or viscosity functions from the phase mobility functions, thus decoupling the dependency on pressure and saturation. It is found that the upscaled oil viscosity provides more accurate predictions than the upscaled relative permeabilities, especially at early time. This is because that the rapid change of pressure at early stage is captured sufficiently in the upscaled oil viscosity (as a function of pressure). The use of upscaled viscosity function in multiphase upscaling is new, and has not been presented in previous studies. We also introduce a grouping technique to reduce the number of upscaled flow functions in coarse-scale models. This is based on an observation that there is a strong correlation between the upscaled flow functions and the coarse-scale well-block permeabilities. The proposed methods are applied to realistic models from heavy-oil fields. For cases considered, the near-well multiphase flow upscaling considerably improves upon the standard coarse models. The use of upscaled relative permeability and viscosity functions, as well as the grouping of upscaled flow functions, provides practical applicability for fast and accurate forecast using coarse-scale models.
Diversity in Diploid, Tetraploid, and Mixed Diploid–Tetraploid Populations of Paspalum simplex
Authors: Brugnoli E. A. , Urbani M. H. , Quarin C. L. , Martínez E. J. , Acuña C. A. 
Published: April 2013

ABSTRACTThe tetraploid cytotype of Paspalum simplex Morong has a wide geographical distribution and reproduces by apomixis while the diploid grows in a restricted area in northern Argentina and behaves as cross‐pollinated. The objective was to evaluate the genetic diversity among and within natural diploid and tetraploid populations of P. simplex growing in sympatry and allopatry by studying the phenotypic variability and DNA polymorphisms. Twenty‐three phenotypic traits and 10 inter‐simple sequence repeat (ISSR) molecular markers were used for evaluating the variability present in six populations of P. simplex. Two populations were diploid and four were tetraploid. One of the tetraploid populations was sympatric to a diploid population while the rest of the populations were allopatric. A rich diversity was observed for specific traits, especially for seasonal biomass yield, presence of a terminal raceme in the inflorescence, and leaf pubescence. The 2x and 4x populations growing in proximity were closely related. Diversity was higher within diploid populations when compared with the evaluated tetraploid populations. Among the tetraploid populations, the one sympatric with a diploid population exhibited the greatest diversity. Gene flow occurs between 2x sexual and 4x apomictic populations of P. simplex. Diploid populations seem to be the main source of the diversity observed among tetraploid populations.
Molecular Markers for Leaf Rust Resistance Gene Lr42 in Wheat
Authors: Liu Zhengli , Bowden Robert L. , Bai Guihua 
Published: April 2013

ABSTRACTWheat leaf rust, caused by Puccinia triticina Eriks., is an important wheat (Triticum aestivum L.) foliar disease worldwide. Growing cultivars incorporating genetic resistance is one of the most effective approaches for disease control. Leaf rust resistance gene Lr42 was identified from a wheat relative, Aegilops tauschii Coss. (goatgrass), and has been transferred into hard winter wheat. A previous study identified two markers closely linked to the gene on the short arm of chromosome 1D (1DS) using a near‐isogenic population, but flanking markers for Lr42 were not found. In this study, a new mapping population was developed from a cross between ‘KS93U50’ (a Lr42 carrier) and a susceptible parent, ‘Morocco’. An F2 population was analyzed with all simple sequence repeat (SSR) markers available from chromosome 1D and F2 plants and F3 families were evaluated for seedling resistance to isolate PNMRJ, a rust isolate avirulent to Lr42. The F2 and F3 rust data showed that Lr42 was recessive. Seven markers formed the linkage group on chromosome 1DS. The Lr42 region was flanked by two SSR markers, Xwmc432 and Xgdm33, at 18 cM apart. The results confirmed that Lr42 is positioned on the distal end of chromosome 1DS. The flanking markers for Lr42 should be useful for map‐based cloning and marker‐assisted pyramiding of Lr42 with other leaf rust resistance genes.
Comparative Performance of Early‐maturing Maize Cultivars Developed in Three Eras under Drought Stress and Well‐watered Environments in West Africa
Authors: Badu‐Apraku B. , Oyekunle M. , Menkir A. , Obeng‐Antwi K. , Yallou C. G. , Usman I. S. , Alidu H. 
Published: April 2013

ABSTRACTMaize (Zea mays L.) is a major staple crop in West Africa and has the potential to mitigate the food insecurity in the subregion. However, maize grain yield is severely constrained by drought. A study was conducted at 13 locations in West Africa for 2 yr to determine genetic gains in yield of cultivars developed during three eras, 1988 to 2000 (first‐generation cultivars), 2001 to 2006 (second‐generation cultivars), and 2007 to 2010 (third‐generation cultivars) under drought and optimal conditions. Under drought, yield ranged from 1346 kg ha⁻1 for first‐generation cultivars to 1613 kg ha⁻1 for third‐generation cultivars with a genetic gain of 1.1% yr−1. Under optimal conditions, yield gain ranged from 3363 kg ha⁻1 for first‐generation cultivars to 3956 kg ha⁻1 for third‐generation cultivars with genetic gain of 1.3%. The average rate of increase in yield was 14 and 40 kg ha⁻1 yr⁻1 under drought and optimum conditions. Genetic gains in yield from first‐ to third‐generation cultivars under drought was associated with improved plant aspect and husk cover, whereas under optimum conditions it was associated with plant and ear aspects, increased ears per plant, plant and ear heights, and improved husk cover. Cultivars TZE‐W DT C2 STR, DTE‐W STR Syn C1, DT‐W STR Synthetic, 2009 DTE‐W STR Syn, and EV DT‐W 2008 STR were high yielding and stable across drought environments. Substantial progress has been made in breeding for drought tolerance during the last three decades.
Drought Tolerance in Maize: Indirect Selection through Secondary Traits versus Genomewide Selection
Authors: Ziyomo Cathrine , Bernardo Rex 
Published: April 2013

ABSTRACTPhenotyping maize (Zea mays L.) for drought tolerance is costly and time consuming. Our objectives were to determine (i) the heritability, genetic variance, and genetic correlations for grain yield and secondary traits in maize under drought and (ii) the efficiency of indirect selection through secondary traits versus genomewide selection. Testcrosses of 238 recombinant inbreds from the intermated B73 × Mo17 population were evaluated in multilocation trials under managed drought and nondrought (control) conditions in Minnesota in 2009 and 2010. Mean grain yield under drought was 52% of the mean grain yield in the control experiments. Heritability for grain yield was 0.37 ± 0.08 under drought and 0.60 ± 0.04 in the control experiments. Indirect selection based on anthesis‐silking interval, leaf senescence, leaf chlorophyll content, or grain yield in control conditions was not predicted to be more efficient than direct selection for grain yield under drought. Genomewide selection (with 998 markers) for grain yield under drought had a predicted relative efficiency of 1.24. Genetic correlations estimated from genomewide marker effects agreed well with correlations estimated from genetic covariances. Given that multiple cycles of marker‐based selection can be done per year in maize and that genotyping is cheaper than phenotyping for drought tolerance, our results suggest that genomewide selection could increase genetic gains per unit time for grain yield under drought.
Interventional Nephrology
Authors: Urbanes Aris Q. 
Published: April 2013

Summary
The patient’s vascular access is critical in ensuring that hemodialysis is successful, effective, relatively uncomplicated, and consistently reproducible from one treatment to another. The choice of vascular access is dictated by a multitude of factors, some of which are generalizable to a larger system, and others of which are flavored by local experience and expertise; an important fraction is specific to the patient presenting to the clinician at a particular point in time. Some of these factors, such as patient age and sex, are not modifiable; others, like comorbidity, vessel size and urgency of presentation to the renal provider, are manageable and sometimes modifiable. The role of the autologous arteriovenous fistula as the ideal conduit for hemodialysis treatments is well established. The role of the prosthetic graft warrants discussion and investigation to most optimally apply to patients this important alternative within the armamentarium of vascular access.