bluuebunny/crossref_metadata_2025_split huggingface dataset:
Applying Field-Proven Surface Modified Proppant SMP to Increase Gas Production: A Case Study from Marcellus Shale
Authors: Bammidi Vidya Sagar , Mortazavi Millad , McClure Mark , Kakadjian Sarkis , Sobernheim Dave 
Published: October 2019

Abstract
In shale formations, operators are constantly seeking new technologies to improve proppant transport and conductivity in order to boost production. A novel technique known as surface modified proppant (SMP) has been pumped in more than a dozen wells in the United States, with proven results of increased production. This paper demonstrates and analyzes a case study for a Marcellus shale development where two wells are presented. Well A applied the SMP technique while the offset, Well B, was stimulated without the technology. After three years, Well A yielded an 18% increase in normalized cumulative gas production over the offset Well B.
In presenting the benefits of this technique, the paper provides a brief overview of the development of the conductivity enhancer; the case study; 3D reservoir and hydraulic fracturing simulator selection; model setup and simulation results. SMP is a chemical additive that, when pumped, creates a buoyancy effect of proppant particles upon entering the fracture network. This dynamic SMP application also propels proppant transportation, prevents proppant settling and enhances the fracture network conductivity by increasing the volume by which sand inhabits the fracture network. Increasing the proppant pack height enables deeper penetration into the fracture network, allowing for an increase in proppant distribution and ultimately enhancing the stimulated rock volume (SRV). We have been able to prove the application in both the lab and field scale tests. The impact of the SMP proppant is investigated by performing numerical simulations of hydraulic fracturing and subsequent production.
Along with clear results showing better proppant placement using the simulator with the conducted study, we further explain the completion effectiveness. We outline advantages and the ease of pumping the SMP, including design optimization, thus making this technology cost beneficial.
Analyses of Multiple Pressure Drops on the Potential Productivity of Shale Wells
Authors: Gorell Sheldon , Browning Jim , Andrews Justin 
Published: October 2019

Abstract
Production from shales can be dependent on many things, including multiple reservoir properties, drilling, completion and production methods. Designs and analyses often focus on drilling and completion issues, such as number of stages, wellbore length and fracture properties, such as conductivity, length, spacing and complexity. As a result, many aspects of the reservoir, fractures and production methods can be significant. Flow from the reservoir to production points is driven by pressure drops. If an entire well including fractures and surrounding reservoir is considered as a single system, then the production behavior is driven by the magnitude of three pressure drops and corresponding resistances to flow in the system. Those that need to be considered are: pressure drop between the reservoir and the fractures, pressure drop along the fractures to the wellbore perforations and pressure drop along the wellbore to the pump inlet or tubing head. Different aspects of the well/fracture/reservoir system become important, or unimportant, depending on the relative magnitude of these pressure drops and resistances to flow. For example, many people believe that fractures should be as long as possible assuming they can be restricted to zones of interest and do not interfere with other wells and/or fractures. However, since the pressure along a fracture increases as you move further away from the wellbore, increasing fracture length can have diminishing returns for reservoirs with small reservoir to fracture pressure drops and/or low fracture conductivities. Similar effects pertain to number of fractures, fracture spacing and wellbore lengths. This paper analyzes effects of different reservoir, fracture and wellbore properties and the influence of different pressure drops on shale well productivity.
Improved Analysis of Stimulated Reservoir Volumes in Unconventional Reservoirs Using Supervised Learning Techniques
Authors: Tandon Saurabh 
Published: October 2019

Abstract
"Sweet spots" in the unconventional reservoirs such as organic-rich mudrocks are zones with high productivity. However, identifying such regions in unconventional reservoirs depends non-only on their petrophysical and but also on their geomechanical properties. Supervised learning methods can help in integrating numerical simulation and legacy field data in sweet-spot identification workflows and enhance their analysis in complex reservoirs. The objectives of this paper are to: (i) demonstrate the use of supervised learning in parameter selection and evaluation for fracture design and (ii) provide non-linear models for sweet-spot analysis in complex reservoirs.
We used fracture simulator that combines with fracture deformation with fluid-flow in discrete fracture networks. We started by selecting different geomechanical rock properties related to its fracability. We then used quasi-random design approach to obtain wide variation in aforementioned properties and performed 200 fracture simulations using the hydraulic fracturing simulator. We used the short-term Stimulated Reservoir Volumes (SRV) obtained at the end of numerical simulations, to quantify the performance of hydraulic fracturing operations. We used supervised learning techniques like support vector machines, decision trees, and random forests to perform parameter ranking and create non-linear regression models that can correlate the SRV to formation geomechanical properties.
The inputs for the analysis are: initial aperture, toughness, dilation angle, closure stress, and friction coefficient of initial fractures, stress anisotropy, shear modulus and a ratio of the reservoir rock. We analyzed the results using β-linear and multinomial regression, support vector machines, decision trees, and random forests. The linear models and non-linear models can explain up to 89.1% of output variance. The classification accuracy of support vector machines was at most 35% higher than other algorithms like random forests. Parameter rating using non-linear models showed that stress anisotropy and dilation angle demonstrated the highest effect on SRVs. Shear modulus and fracture toughness show minimal effect on the SRV but these parameters might still be useful they could be correlated to other formation parameters.
The outcomes of this paper demonstrated that parameters pertaining to unpropped fracture conductivity play a significant role in determining the success of hydraulic fracturing treatments. We have also compared the performances of supervised machine learning algorithms in assessing the impact of rock properties on fracturing treatments. Such supervised machine learning algorithms can help integrate field legacy data and numerical simulation outputs to develop proxy models that improve sweet-spot analysis and production estimates in unconventional reservoirs.
Evaluation of Reservoir Compartmentalization Through Organic Geochemistry jawdah Field, South of Oman
Authors: Al Shukairi Saleem Abdullah 
Published: October 2019

AbstractAs the oil and gas industry has been investigating the challenges in identifying reservoir compartmentalization and interpreting the negative influences it generates, diverse disciplines within the oil and gas industry have presented beneficial approaches to inspect and reduce the challenges found while exploring and appraising oil fields. despite the various pieces of literature that have been published in this field stating that reservoir compartments are either structurally or stratigraphically in origin depending on the depositional facies or fault geometry. This study presents, geochemical data from twenty oil samples which are used to investigate horizontal and vertical compartmentalization of the Jawdah Field, which is located in the south of Oman. The data were intended to identify the causes of the segmentation using fluid properties. The results from each oil sample are integrated with carbon isotopes, whole-oil gas chromatography, saturates, aromatics, resins and asphaltenes (SARA) analysis and biomarkers in order to detect different variations in fluid composition that may be lead to better understanding of reservoir compartmentalization. Based on these four analyses, the research findings indicate that Jawdah oils are derived from a single source rock (Huqf oils). The identification of the Huqf source rock was based on the similarities between pristane and phytane peaks from the whole-oil gas chromatography data and the carbon isotopes for the Jawdah oils and from the Grantham (1988) paper. However, the API gravities in Jawdah field varied ranging from light to moderately heavy oil (20-33 API), indicating a possibility of other geological factors affected the alteration of the crude oil. Therefore, these oils were further characterized by interpreting the level of maturation and biodegradation ratios using biomarker signatures. This combination of methods has provided a more advanced method of investigating and interpreting compartmentalized reservoirs and it will lead to enhancing recovery. It was found that the Gharif and Al Khlata reservoir units are not in communication, potentially impacting well design, and field development planning.
Trial Forge Guidance 2: How to decide if a further Study Within A Trial (SWAT) is needed
Authors: Treweek Shaun , Bevan Simon , Bower Peter , Briel Matthias , Campbell Marion , Christie Jacquie , Collett Clive , Cotton Seonaidh , Devane Declan , Feky Adel El , Galvin Sandra , Gardner Heidi , Gillies Katie , Hood Kerenza , Jansen Jan , Littleford Roberta , Parker Adwoa , Ramsay Craig , Restrup Lynne , Sullivan Frank , Torgerson David , Tremain Liz , von Elm Erik , Westmore Matthew , Williams Hywel , Williamson Paula R , Clarke Mike 
Published: October 2019

Abstract
The evidence base available to trialists to support trial process decisions– e.g. how best to recruit and retain participants, how to collect data or how to share the results with participants – is thin. One way to fill gaps in evidence is to run Studies Within A Trial, or SWATs. These are self-contained research studies embedded within a host trial that aim to evaluate or explore alternative ways of delivering or organising a particular trial process. SWATs are increasingly being supported by funders and considered by trialists, especially in the UK and Ireland. At some point, increasing SWAT evidence will lead funders and trialists to ask : given the current body of evidence for a SWAT, do we need a further evaluation in a another host trial? A framework for answering such a question is needed to avoid SWATs themselves contributing to research waste. This paper presents criteria on when enough evidence is available for SWATs that use randomised allocation to compare different interventions.
Seroprevalence of Hepatitis B Virus among antenatal clinic attendees in Gamawa Local Government Area, Bauchi State, Nigeria
Authors: MUSTAPHA GARBA UMAR , Ibrahim Abdulrasul , Balogun Muhammad Shakir , Umeokonkwo Chukwuma David , Mamman Aisha Indo 
Published: October 2019

Abstract
Background: Hepatitis B is a potentially life-threatening liver infection and a major global health problem. It causes chronic infection and puts people at high risk of death from cirrhosis and liver cancer. WHO estimated 257 million people are living with hepatitis B virus (HBV) infection and in 2015 alone HBV resulted in to 887,000 deaths globally. We determined the prevalence and associated factors of hepatitis B virus infection among Antenatal Care (ANC) attendees in Gamawa Local Government Area, Bauchi State. Methods: We conducted a descriptive cross-sectional, health facility-based study between March and April 2018. We used systematic random sampling technique to recruit 210 pregnant women aged 15-49 years. With a structured questionnaire, we interviewed the respondents and collected blood sample to test for hepatitis B surface antigen. We calculated frequencies, means, proportions, and tested for associations using Epi Info 7.2 and Microsoft Excel. Results: The mean age of respondents was 24.5 ± 6.0 years; 112 (53%) of whom were younger than 25 years. All were married, 183 (87%) had no formal education and up to 190 (90%) were employed. Overall, 14 (6.7%) tested positive for HBsAg; women aged ≥35 years had the highest prevalence (10%). None with tertiary education tested positive and women married before 18 years had 13 (6.2%) prevalence. Conclusions: The prevalence of HBsAg among pregnant women in Gamawa LGA was 6.7% which is quite lower than the national prevalence reported. We recommended improved surveillance of HBV infection and screening of women attending ANC. Keywords: Hepatitis B virus, Hepatitis B Surface antigen, Prevalence, Pregnancy, Health facilities, Hepatitis B
A Sense of Place: Transcriptomics Identifies Environmental Signatures in Cabernet Sauvignon Berry Skins in the Late Stages of Ripening.
Authors: Cramer Grant R. , Cochetel Noé , Ghan Ryan , Destrac-Irvine Agnès , Delrot Serge 
Published: October 2019

Abstract
Background Grape berry ripening is influenced by climate, the main component of the “terroir” of a place. Light and temperature are major factors in the vineyard that affect berry development and fruit metabolite composition. Results To better understand the effect of “place” on berry ripening, transcript abundances in Cabernet Sauvignon berries grown in Bordeaux were compared to those in Reno during the late stages of berry development at similar berry sugar levels (19 to 26 °Brix, total soluble solids (TSS)). Day lengths were similar in both locations but day temperatures were warmer and night temperatures were cooler in Reno. TSS was lower in Bordeaux berries compared to Reno at maturity levels considered optimum for harvest. RNA-seq analysis identified 4,455 differentially expressed genes (DEGs) between Bordeaux and Reno grape skins at 22°Brix. Top DEG gene ontology categories involved response to stimulus (1464 genes), biosynthesis (1260 genes) and response to stress (834 genes). Some DEGS included genes encoding terpene synthases, cell wall enzymes, kinases, transporters, transcription factors and photoreceptors. Most circadian clock genes had higher transcript abundance in Bordeaux. The plant temperature sensor phytochrome B was linked with Reveille 1 expression, which is part of the circadian clock output pathway that affects seed dormancy. Bordeaux berries had higher transcript abundance with DEGs associated with seed dormancy, light, auxin, ethylene signaling, powdery mildew infection, phenylpropanoid, carotenoid and terpenoid metabolism, whereas Reno berries were enriched with DEGs involved in water deprivation, cold response, ABA signaling and Fe homeostasis. Conclusions Transcript abundance profiles in the berry skins at maturity were highly dynamic. RNA-seq analysis identified a common core set of ripening genes that do not depend on rootstock, vineyard management, plant age, soil and climatic conditions. Most DEGs could be associated with different environmental conditions that affected the berries in the two locations and may be potentially controlled in different ways by the vinegrower to adjust final berry composition and reach a desired result. Temperature, light, water status and fungal infection were identified to be some of the most influential factors that affected differential gene expression and the quality trait pathways associated with them.
Chronic Hypersensitivity Pneumonitis In The Southeastern United States: An Assessment Of How Clinicians Reached The Diagnosis
Authors: Gu Jessie , Tsai Chen-Liang , Wysham Nicholas , Huang Yuh-Chin Tony 
Published: October 2019

Abstract
Background: Chronic hypersensitivity pneumonitis (cHP) is a disease caused by exposure to inhaled environmental antigens. Diagnosis of cHP is influenced by the awareness of the disease prevalence, which varies significantly in different regions, and how clinicians utilize relevant clinical information. We conducted a retrospective study to evaluate how clinicians in the Southeast United States, where the climate is humid favoring mold growth, diagnosed cHP using items identified in the international modified Delphi survey of experts, i.e., environmental exposure, CT imaging and lung pathology, Methods: We searched Duke University Medical Center database for patients over the age of 18 with a diagnosis of cHP (ICD-9 code: 495) between Jan. 1, 2008 to Dec. 31, 2013 using a query tool, Duke Enterprise Data Unified Content Explorer (DEDUCE). Results: Five hundred patients were identified and 261 patients had cHP confirmed in clinic notes by a pulmonologist or an allergist. About half of the patients lived in the Research Triangle area where our medical center is located, giving an estimated prevalence rate of 6.5 per 100,000 persons. An exposure source was mentioned in 69.3% of the patient. The most common exposure sources were environmental molds (43.1%) and birds (26.0%). We used Venn diagram to evaluate how the patients met the three most common cHP diagnostic criteria: evidence of environmental exposures (history or precipitin) (E), chest CT imaging (C) and pathology from lung biopsies (P). Eighteen patients (6.9%) met none of three criteria. Of the remaining 243 patients, 135 patients (55.6%) had one (E 35.0%, C 3.3%, P 17.3%), 81 patients (33.3%) had two (E+C 12.3%, E+P 17.3%, C+P 4.9%), and 27 patients (11.1%) had all three criteria (E+C+P). Overall, 50.6% of patients had pathology from lung biopsy compared to 31.6% with CT scan. Conclusions: Environmental mold was the most common exposure for cHP in the Southeast United States. Lung pathology was available in more than half of cHP cases in our tertiary care center, perhaps reflecting the complexity of referrals. Differences in exposure sources and referral patterns should be considered in devising future diagnostic pathways or guidelines for cHP.
Occurrence and seasonal variation of human Plasmodium infection in Punjab Province, Pakistan
Authors: Qureshi Naveeda Akhtar , Fatima Huma - , Afzal Muhammad , Khattak Aamer Ali , Nawaz Muhammad Ali 
Published: October 2019

Abstract
Background:
Background: Malaria is the fifth leading cause of death worldwide. Pakistan is considered as a moderate malaria-endemic country but still, 177 million individuals are at risk of malaria. Roughly 60% of Pakistan’s population, live in malaria-endemic regions. The present study is based upon the survey of various health care centers in 10 major cities of Northern and Southern Punjab to find out the malarial infection patterns in 2015. The diagnosis, seasonal variations, age and gender-wise distribution of Plasmodium spp. circulating in the study area were also included in the objectives.
Methods: The malaria-suspected patients ‘16075’ were enrolled for malaria diagnosis using microscopy, out of which 925 were malaria positive which were processed for molecular analysis using nested PCR. The 18S rRNA genes of Plasmodium species were amplified, sequenced, blast and the phylogenetic tree was constructed based on sequences using online integrated tool MEGA7.
Results: The 364 cases recruited from Northern Punjab with the highest incidence in Rawalpindi (25.5%) and lowest in Chakwal (15.9%). From Southern Punjab 561 cases were enlisted Rajanpur (21.4%) maximum and lowest from Multan and Rahim Yar Khan (18%). The slide positivity rate, annual parasite incidence, and annual blood examination rates were 5.7 per 1000 population, 0.1%, and 0.2% respectively. The only P. vivax (66.7%), P. falciparum (23.7%) and mixed infection by these two species (9.6%) were diagnosed. The same trend ( P. vivax > P. falciparum > mixed infection) in species identification %age was confirmed from molecular analysis. However, the occurrence of malaria was higher in Southern Punjab (5.5%) as compared to the Northern Punjab (4.0%). The overall malaria percentage occurrence of treatment-seeking patients in all recruited cities of Punjab was 4.9%. The age-group of 1-20 and males among genders were more affected by malaria. The comparison of different seasons showed that the malaria infection was at a peak in Summer and post-monsoon.
Conclusion: The incidence of malaria was high in the flood infected rural areas of Southern Punjab, Summer, and post-monsoon. The age group (1-20) and gender-wise males were more affected by malaria.
A detailed in silico analysis of secondary metabolite biosynthesis clusters in the genome of the broad host range plant pathogenic fungus Sclerotinia sclerotiorum
Authors: Graham-Taylor Carolyn , Kamphuis Lars G , Derbyshire Mark 
Published: October 2019

Abstract
Background

The broad host range pathogen Sclerotinia sclerotiorum infects over 400 plant species and causes substantial yield losses in crops worldwide. Secondary metabolites are known to play important roles in the virulence of plant pathogens, but little is known about the secondary metabolite repertoire of S. sclerotiorum. In this study, we predicted secondary metabolite biosynthetic gene clusters in the genome of S. sclerotiorum and analysed their expression during infection of Brassica napus using an existing transcriptome data set. We also investigated their sequence diversity among a panel of 25 previously published S. sclerotiorum isolate genomes.Results

We identified 80 putative secondary metabolite clusters. Over half of the clusters contained at least three transcriptionally coregulated genes. Comparative genomics revealed clusters homologous to clusters in the closely related plant pathogen Botrytis cinerea for production of carotenoids, hydroxamate siderophores, DHN melanin and botcinic acid. We also identified putative phytotoxin clusters that can potentially produce the polyketide sclerin and an epipolythiodioxopiperazine. Secondary metabolite clusters were enriched in subtelomeric genomic regions, and those containing paralogues showed a particularly strong association with repeats. The positional bias we identified was borne out by intraspecific comparisons that revealed putative secondary metabolite genes suffered more presence / absence polymorphisms and exhibited a significantly higher sequence diversity than other genes.Conclusions

These data suggest that S. sclerotiorum produces numerous secondary metabolites during plant infection and that their gene clusters undergo enhanced rates of mutation, duplication and recombination in subtelomeric regions. The microevolutionary regimes leading to S. sclerotiorum secondary metabolite diversity have yet to be elucidated. Several potential phytotoxins documented in this study provide the basis for future functional analyses.