bluuebunny/crossref_metadata_2025_split huggingface dataset:
Optimizing Fracturing Design and Well Spacing with Complex-Fracture and Reservoir Simulations: A Permian Basin Case Study
Authors: Xiong Hongjie , Liu Songxia , Feng Feng , Liu Shuai , Yue Kaimin 
Published: December 2019

Summary
Proper lateral and vertical well spacing is critical to efficiently develop unconventional reservoirs. Much research has focused on lateral well spacing, but little on vertical spacing, which is important and challenging for stacked-bench plays such as the Permian Basin. Following the previous single-well study (Xiong et al. 2018), we performed a seven-well case study to optimize completion design and 3D well spacings, by integrating the latest complex-fracture-modeling and reservoir-simulation technologies. Those seven wells are located at the same section but also are vertically placed in four different zones in the Wolfcamp Formation in the southern Midland Basin.
With the latest modeling technologies, we first built a 3D geological and geomechanical model, and full wellbore fracture-propagation model for these seven wells, and then calibrated the model with multistage-fracturing pumping history of each well. The resulting model was then converted to an unstructured-grid-based reservoir-simulation model, which was then calibrated with production history. On the basis of the local geomechanical characterization, as well as confidence in the capacity of the models from our previous study, we conducted experiments in fracturing modeling to study the impact of different completion design parameters on fracture propagation, including cluster spacing, fracturing-fluid viscosity, pumping rate, and fluid and proppant intensities. With the statistical distributions of fracture length and height from different completion designs, we then optimized the completion design, and studied lateral and vertical well spacings.
The results show the following. The resulting fracture length and height from multistage fracturing treatments are in log-normal distribution, which provides great insights on the probability of well interference/fracture hits and drained/undrained reservoir volumes. Both fracture hits/well interference and drainage volume depend on the well spacings and corresponding well completion designs The hydraulic-fracture length, height, and network complexity mainly depend on in-situ stress, cluster spacing, cluster number per stage, and fluid and proppant intensity. For the Wolfcamp Formation in the southern Midland Basin, tighter cluster spacing with fewer perforation clusters per stage and high fluid and proppant intensity, might create larger fracture surface area, which will increase the initial production rate and the ultimate recovery.
Therefore, we can reasonably model complicated fracture propagation and well performance with the latest modeling technologies, and optimize both lateral and vertical well spacings, and the corresponding completion design. The application of those technologies could help operators save significant time and costs on well-completion and -spacing pilot projects and, thus, speed up field-development decisions. In addition, we will demonstrate a novel workflow to perform this job.
Model for Asymmetric Hydraulic Fractures with Nonuniform-Stress Distribution
Authors: Hu Xiaofan , Liu Guoqing , Luo Guofan , Ehlig-Economides Christine 
Published: December 2019

Summary
Engineers commonly expect symmetric fracture wings in multiple-transverse-fracture horizontal wells. Microseismic surveys have shown that asymmetric hydraulic fractures grow away from the recent fractured wells and grow toward previously produced wells. This might be caused by the elevated stress around the recently fractured well and the reduced stress near the depleted wells. This paper presents the asymmetric fracture growth observed by the microseismic events, develops a simple model to simulate the fracture propagation, and discusses its effect on the well productivity.
Motivated by the microseismic observations, we developed a simple 2D fracture model to simulate asymmetric fracture wings that can capture the behavior of fracture hits between two adjacent horizontal fractured wells. Fluid leakoff during fracture propagation is considered in the model. The effect of asymmetric fractures on production is evaluated with numerical simulations.
The newly developed fracture model shows that the fracture can grow asymmetrically if the horizontal well is near where the stress field is different between its two sides. Numerical simulation is used to quantify the productivity reduction caused by asymmetric hydraulic fractures. Our results provide a reason for why asymmetric fractures occur and demonstrate that they do penalize well performance. Our model suggests the importance of fracturing under a balanced-stress distribution that benefits long-term production. Use of this model also suggested that an optimized hydraulic-fracturing-treatment design will improve the overall performance of multiple parallel wells, which minimizes or avoids asymmetric fracture wings.
The fracture-propagation model and productivity model provide simple but profound guidelines for well-pad management, including well spacing, stage planning and spacing, and completion and production order.
Multiscale Integration for Karst-Reservoir Flow-Simulation Models
Authors: Correia Manuel Gomes , von Hohendorff Filho João Carlos , Schiozer Denis Jose 
Published: December 2019

Summary
The significant oil reserves related to karst reservoirs in a Brazilian presalt field add new frontiers to the development of upscaling procedures to reduce time for numerical simulations. This work aims to represent karst reservoirs in reservoir simulators using special connections between matrix medium and karst medium, each modeled in different grid domains of a single-porosity flow model. This representation intends to provide a good relationship between accuracy and simulation time.
The concept follows the embedded discrete-fracture model (EDFM) developed by Li and Lee (2008) and later extended by Moinfar et al. (2014); however, this work extends the approach for karst reservoirs [embedded discrete-karst model (EDKM)] by adding a representative volume through gridblocks to represent karst geometries and porosity. For the extension of the EDFM approach in a karst reservoir, we adapt the methodology to four stages: construction of a single-porosity model with two grid domains; geomodeling of karst and matrix properties, each for the corresponding grid domain; application of special connections through the conventional reservoir simulator to represent the transmissibility between the matrix and the karst medium; and calculation of transmissibility between the matrix and the karst medium.
For a proper verification, we applied the EDKM methodology in a carbonate reservoir with megakarst structures, which consists of nonwell-connected enlarged conduits and greater than 300 mm of aperture. The reference model was a refined grid with karst features explicitly combined with matrix facies, including coquinas interbedded with mudstones and shales. The gridblock of the reference model measures approximately 10 × 10 × 1 m. For the simulation model, the matrix-grid domain has a gridblock size of approximately 100 × 100 × 5 m. The karst-grid domain had the same block size as the refined grid. Flow in the individual karst-grid domain or matrix-grid domain is governed by Darcy's equation, implicitly solved by a simulator. However, the transmissibility for the special connections between karst and matrix blocks is calculated as a function of open area to flow, matrix permeability, and block-center distance. The matrix properties were scaled up through conventional analytical methods. The results show that EDKM had a considerable performance regarding a dynamic matching response with the reference model, within a reduced simulation time, while maintaining a higher dynamic resolution in the karst-grid domain without using an unconstructed grid.
This work aims to contribute to the extension of the EDFM approach for karst reservoirs, which can be applied to commercial finite-difference reservoir simulators. This could be a solution to reduce simulation time without disregarding the explicit representation of karst features in structured grids.
Recent Development and Remaining Challenges of Iron Sulfide Scale Mitigation in Sour-Gas Wells
Authors: Chen Tao , Wang Qiwei , Chang Frank , Aljeaban Norah , Alnoaimi Khalid 
Published: December 2019

Summary
Iron sulfide scale deposition can be a significant flow-assurance issue in sour-gas production systems. It can deposit along the water-flowing path from the near-wellbore reservoir region to the surface equipment, which results in formation damage, causes tubing blockage, interferes with well intervention, and reduces hydrocarbon production.
The main objectives of this paper are to review the new advancements and remaining challenges concerning iron sulfide management in sour-gas wells, covering the mechanisms of iron sulfide formation, the mechanical and chemical removal techniques, and the prevention strategies.
In this paper we give a special emphasis to the different mechanisms of iron sulfide formation during well-completion and production stages, especially the sources of ferrous iron (Fe2+) for scale deposition. It is essential to understand the root cause to identify and develop suitable technologies to manage the scale problem. We also summarize the latest developments in mechanical methods and chemical dissolvers for the removal of iron sulfide deposited on downhole tubing. The capabilities of the current chemical dissolvers are discussed, and the criteria for effective dissolvers are provided to serve as guides for future development. Then, we provide an overview of recent developments on iron sulfide prevention technologies and treatment strategies. We differentiate the treatment approaches for corrosion byproduct and scale precipitation and scale-inhibitor deployment through continuous-injection and squeeze treatments. Finally, we outline the technical gaps and areas for further research-and-development (R&D) efforts.
We provide the latest review on iron sulfide formation and mitigation, with an attempt to integrate viable solutions and showcase workable practices.
Combining therapy with recombinant human endostatin and cytotoxic agents for recurrent disseminated glioblastoma: a retrospective study
Authors: Ge Jing-jing , Li Cheng , Qi Shao-pei , Xue Feng-jun , Gao Zhi-meng , Yu Chun-jiang , Zhang Jun-ping 
Published: December 2019

Abstract
Background: The optimal chemotherapeutics of recurrent disseminated glioblastoma has yet to be determined. We analyzed the efficacy and safety of recombinant human endostatin (rh-ES) combined with temozolomide and irinotecan in patients with recurrent disseminated glioblastoma.
Methods: We retrospectively reviewed 30 adult patients with recurrent disseminated glioblastoma treated with this combination chemotherapy at Department of Neuro-Oncology, Sanbo Brain Hospital, Capital Medical University of China from November 2009 to August 2018. Temozolomide was given orally at 200mg/m 2 daily for 5 days and rh-ES was administrated 15 mg/d daily for 14 days of each 28-day treatment cycle. Irinotecan was given intravenously every 2 weeks on a 28-day cycle at 340 mg/m 2 or 125 mg/m 2 depending on antiepileptic drugs. Primary endpoint was progression-free survival (PFS) at 6 months (6m-PFS).
Results: The 6m-PFS was 23.3%. The median PFS was 3.2 months. The overall survival rate (OS) at 12 months was 28.6%. The median OS was 6.9 months. Six out of 30 (20%) patients demonstrated partial radiographic response and 11 (36.7%) remained stable. The PFS of the 6 patients who got partial response was 5.8, 6.3, 6.9, 13.6, 15.8 and 16.6 months, respectively, and the median time interval of first response was 4 (range, 2.0-6.6) months. The most common adverse events were hematologic toxicities and gastrointestinal effects. The Grade ≥ 3 adverse event was hematologic toxicities. The adverse events were manageable.
Conclusions: Rh-ES, in combination with cytotoxic drugs, was an alternative effective regimen with manageable toxicities in treatment of recurrent disseminated glioblastoma.
Systematical identifications of prognostic meaningful lung adenocarcinoma subtypes and the underlying mutational and expressional characters
Authors: Lv Zhenyang , Lei Ting 
Published: December 2019

Abstract
Background Lung adenocarcinoma (LUAD) is one of the most common cancer types, threatening the human health around the world. However, the high heterogeneity and complexity of LUAD limit the benefits of targeted therapies. This study aimed to identify the key prognosis impacting genes and relevant subtypes for LUAD. Methods We recognized significant mutations and prognosis-relevant genes based on the omics data of 515 LUAD samples from The Cancer Genome Atlas. Mutation significance was estimated by MutSigCV. Prognosis analysis was based on the cox proportional hazards regression (Coxph) model. Specifically, the Coxph model was combined with a causal regulatory network to help reveal which genes play master roles among numerous prognosis impacting genes. Based on expressional profiles of the master genes, LUAD patients were clustered into different sub-types by a consensus clustering method and the importance of master genes were further evaluated by random forest. Results Significant mutations did not influence the prognosis directly. However, a collection of prognosis relevant genes were recognized, where 75 genes like GAPDH and GGA2 which are involved in mTOR signaling, lysosome or other key pathways are further identified as the master ones. Interestingly, the master gene expressions help separate LUAD patients into two sub-types displaying remarkable differences in expressional profiles, prognostic outcomes and genomic mutations in certain genes, like SMARCA4 and COL11A1. Meanwhile, the subtypes were re-discovered from two additional LUAD cohorts based on the top-10 important master genes. Conclusions This study can promote precision treatment of LUAD by providing a comprehensive description on the key prognosis-relevant genes and an alternative way to classify LUAD subtypes.
Cues for different diagnostic patterns of interpersonal violence in a psychiatric sample: an observational study
Authors: Talevi Dalila , Collazzoni Alberto , Rossi Alessandro , Stratta Paolo , Mazza Monica , Pacitti Francesca , Costa Manuela , Crescini Claudio , Rossi Rodolfo 
Published: December 2019

Abstract
Background. Interpersonal violence has increased as a health concern, especially in psychiatry practice, over the last decades. Nevertheless, most patients with stable mental disorders do not present an increased risk of violence, and mental disorder is not a necessary or sufficient cause of violent behaviours. People with mental disorders endorse more often a number of risk factors for violence that could confound this association, such as young age and male gender. The aim of this study was to investigate the effect of age, gender, and diagnosis on reported levels of interpersonal violence in a sample of people with severe mental illness. Methods. The sample was composed of 160 inpatients: 73 with a psychosis within the schizophrenia spectrum, 53 with a mood disorder and 34 with a personality disorder. All patients enrolled in the study were assessed for experiences of victimization and perpetration of interpersonal violence using the Karolinska Interpersonal Violence Scale interview. Demographic variables were also collected. Results. Both violence perpetration and victimization negatively correlated with age. Compared to males, females were exposed to higher degree of victimization in childhood and adulthood, whereas males were more involved in the perpetration of violence in childhood. Personality disorders were associated with higher levels of interpersonal violence, both perpetration and victimization; an interaction effect of gender and diagnosis was also observed for violence perpetration in adulthood. Distinct patterns of interpersonal violence did emerge for the diagnostic groups with mood disorder showing a victimization pattern, personality disorders a perpetration pattern and psychoses less defined patterns. Conclusions. The main finding is that psychotic disorders, mood disorders and personality disorders have different patterns of violent experiences interacting with age and gender. This study offers a better understanding of how gender and age could affect violent behaviours. Moreover, study findings may increase the comprehension of the reason why some mental disorders, compared to others, are more associated with the risk of victimization or perpetration of violence. These patterns could have pathophysiological or pathoplastic meaning addressing clinical and diagnostic trajectories and they could interact with other intervening risk factors.
Understanding the Healthcare Experiences and Needs of African Immigrants in the United States: A Scoping Review
Authors: Omenka Ogbonnaya Isaac , Watson Dennis P. , Hendrie Hugh C. 
Published: December 2019

Abstract

Background: Africans immigrants in the United States are the least-studied immigrant group, despite the research and policy efforts to address health disparities within immigrant communities. Although their healthcare experiences and needs are unique, they are often included in the “black” category, along with other phenotypically-similar groups. This process makes utilizing research data to make critical healthcare decisions specifically targeting African immigrants, difficult. The purpose of this Scoping Review was to examine extant information about African immigrant health in the U.S., in order to develop lines of inquiry using the identified knowledge-gaps. Methods: Literature published in the English language between 1980 and 2016 were reviewed in five stages: (1) identification of the question and (b) relevant studies, (c) screening, (d) data extraction and synthesis, and (e) results. Databases used included EBSCO, ProQuest, PubMed, and Google Scholar (hand-search). The articles were reviewed according to title and abstract, and studies deemed relevant were reviewed as full-text articles. Data was extracted from the selected articles using the inductive approach, which was based on the comprehensive reading and interpretive analysis of the organically emerging themes. Finally, the results from the selected articles were presented in a narrative format. Results: Culture, religion, and spirituality were identified as intertwined key contributors to the healthcare experiences of African immigrants. In addition, lack of culturally-competent healthcare, distrust, and complexity, of the U.S. health system, and the exorbitant cost of care, were identified as major healthcare access barriers.
Use of SOPARC to assess physical activity in parks: do race/ethnicity, contextual conditions, and settings of the target area, affect reliability?
Authors: Marquet Oriol , Hipp J. Aaron , Alberico Claudia , Huang Jing-Huei , Fry Dustin , Mazak Elizabeth , Lovasi Gina S. , Floyd Myron F. 
Published: December 2019

Abstract
Background Since its introduction in 2006, SOPARC (Systematic Observation of Play and Recreation in Communities) has become a fundamental tool to quantify park visitor behaviors and characteristics. We tested SOPARC reliability when assessing race/ethnicity, physical activity, contextual conditions at the time of observation, and settings of target areas to understand its utility when trying to account for individual characteristics of users.Methods We used 4,725 SOPARC observations completed simultaneously by two independent observers to evaluate intraclass correlation and agreement rate between the two observers when trying to assess sex, age group, race/ethnicity, and level of physical activity of urban park users in different park settings. Observations were in 20 New York City parks during Spring and Summer 2017 within the PARC 3 project.Results Observers counted 25,765 park users with high interobserver reliability (ICC=.94; %Agreement.75). Reliability scores were negatively affected by the population being observed, the intensity of physical activity, and the contextual conditions and settings of the target area at the time of observation. Specific challenges emerged when assessing the combination of physical activity and race/ethnicity.Conclusions SOPARC training should aim to improve reliability when assessing concurrent measures such as physical activity, race/ethnicity, age, and sex. Similarly, observing crowded park areas with many active users areas may require more observation practice hours.
Genome-wide systematic characterization of the HAK/KUP/KT gene family and its expression profile during plant growth and in response to low-K+ stress in Saccharum
Authors: Feng Xiaomin , Wang Yongjun , Zhang Nannan , Wu Zilin , Zeng Qiaoying , Wu Jiayun , Wu Xiaobin , Wang Lei , Zhang Jisen , Qi Yongwen 
Published: December 2019

Abstract
Background: Plant genomes contain a large number of HAK/KUP/KT transporters, which play important roles in potassium uptake and translocation, osmotic potential regulation, salt tolerance, root morphogenesis and plant development. Potassium deficiency in the soil of a sugarcane planting area is serious. However, the HAK/KUP/KT gene family remains to be characterized in sugarcane (Saccharum). Results: In this study, 30 HAK/KUP/KT genes were identified in Saccharum spontaneum. Phylogenetics, duplication events, gene structures and expression patterns were analyzed. Phylogenetic analysis of the HAK/KUP/KT genes from 15 representative plants showed that this gene family is divided into four groups (clades I-IV). Both ancient whole-genome duplication (WGD) and recent gene duplication contributed to the expansion of the HAK/KUP/KT gene family. Nonsynonymous to synonymous substitution ratio (Ka/Ks) analysis showed that purifying selection was the main force driving the evolution of HAK/KUP/KT genes. The divergence time of the HAK/KUP/KT gene family was estimated to range from 134.8 to 233.7 Mya based on Ks analysis, suggesting that it is an ancient gene family in plants. Gene structure analysis showed that the HAK/KUP/KT genes were accompanied by intron gain/loss in the process of evolution. RNA-seq data analysis demonstrated that the HAK/KUP/KT genes from clades II and III were mainly constitutively expressed in various tissues, while most genes from clades I and IV had no or very low expression in the tested tissues at different developmental stages. The expression of SsHAK1 and SsHAK21 was upregulated in response to low-K+ stress. Yeast functional complementation analysis revealed that SsHAK1 and SsHAK21 could rescue K+ uptake in a yeast mutant. Conclusions: This study provided insights into the evolutionary history of HAK/KUP/KT genes. HAK7/9/18 were mainly expressed in the upper photosynthetic zone and mature zone of the stem. HAK7/9/18/25 were regulated by sunlight. SsHAK1 and SsHAK21 played important roles in mediating potassium acquisition under limited K+ supply. Our results provide valuable information and key candidate genes for further studies on the function of HAK/KUP/KT genes in Saccharum. Keywords: Saccharum, HAK/KUP/KT, evolution, gene expression, low-K+ stress