bluuebunny/crossref_metadata_2025_split huggingface dataset:
Do Data Mining Methods Matter? : A Wolfcamp “Shale” Case Study
Authors: Zhong Ming , Schuetter Jared , Mishra Srikanta , LaFollette Randy F. 
Published: February 2021

Abstract
Data mining for production optimization in unconventional reservoirs brings together data from multiple sources with varying levels of aggregation, detail, and quality. Tens of variables are typically included in data sets to be analyzed. There are many statistical and machine learning techniques that can be used to analyze data and summarize the results. These methods were developed to work extremely well in certain scenarios but can be terrible choices in others. The analyst may or may not be trained and experienced in using those methods. The question for both the analyst and the consumer of data mining analyses is, “What difference does the method make in the final interpreted result of an analysis?”
The objective of this study was to compare and review the relative utility of several univariate and multivariate statistical and machine learning methods in predicting the production quality of Permian Basin Wolfcamp Shale wells. The data set for the study was restricted to wells completed in and producing from the Wolfcamp. Data categories used in the study included the well location and assorted metrics capturing various aspects of the well architecture, well completion, stimulation, and production. All of this information was publicly available.
Data variables were scrutinized and corrected for inconsistent units and were sanity checked for out-of-bounds and other “bad data” problems. After the quality control effort was completed, the test data set was distributed among the statistical team for application of an agreed upon set of statistical and machine learning methods. Methods included standard univariate and multivariate linear regression as well as advanced machine learning techniques such as Support Vector Machine, Random Forests, and Boosted Regression Trees.
The strengths, limitations, implementation, and study results of each of the methods tested are discussed and compared to those of the other methods. Consistent with other data mining studies, univariate linear methods are shown to be much less robust than multivariate non-linear methods, which tend to produce more reliable results. The practical importance is that when tens to hundreds of millions of dollars are at stake in the development of shale reservoirs, operators should have the confidence that their decisions are statistically sound. The work presented here shows that methods do matter, and useful insights can be derived regarding complex geosystem behavior by geoscientists, engineers, and statisticians working together.
Open-Hole Completion Based Mechanical Diversion of Acid/Chemical Stimulation Operations: Design, Deployment and Field Trial Results
Authors: Carvajal E. I. , Caline Y. , Rylance M. , Rice K. , Waters J. , Wells S. 
Published: February 2021

Abstract
The ubiquitous challenge that is faced by chemical stimulation techniques, of any kind, has always been achieving an economic and efficient distribution of the stimulation solution across the exposed reservoir interval. Many have approached this problem from a chemical perspective and others from the use of additives for mechanical diversion; however the very nature of stimulation itself means that a changing injection profile will make efficient diversion by such techniques uncertain and unpredictable. Instead, rather than relying on serendipitous deployment techniques, the approach described and reported here places true mechanical diversion as part of the well construction process. This paper will completely describe the process and achievements to date, including successful application in a number of horizontal wells completed in the Austin Chalk, as part of an overall deployment plan.
Essentially, this new completion system comprises of multiple pressure actuated assemblies, distributed along the liner/casing. These assemblies, when activated, allow the lateral deployment of forty-foot needles, radially distributed at ninety-degree phasing around the casing, into the unstimulated reservoir. These subs can be precisely located across pre-selected intervals and thereby provide certainty of acid treatment distribution. The acid is pumped through the needles themselves during stimulation; however production takes place through a suite of ports. A bespoke debris basket may be run, after the stimulation treatment, in order to recover a suite of needle deployment indicators. This run, if performed, effectively establishes the success of the deployment.
In order to demonstrate the concept and avoid the high-cost environment of the North Sea, a low cost field trial location was sought and identified. An Austin chalk operator was looked for that had an extensive horizontal candidate well set available for re-completion in open-hole. A number of candidate wells were then identified and the wells were recompleted and stimulated with this new system. This paper will present the entire suite of data related to these deployments, stimulation operations, lessons learned, production impact and potential. This novel technology was greatly assisted, supported and delivered via the Joint Chalk Research (JCR) council, comprising of some ten operating companies that encourage, fund and drive the development of carbonate completion and stimulation solutions.
A Peridynamics Model for the Propagation of Hydraulic Fractures in Heterogeneous, Naturally Fractured Reservoirs
Authors: Ouchi Hisanao , Katiyar Amit , Foster John T. , Sharma Mukul M. 
Published: February 2021

Abstract
A novel fully coupled hydraulic fracturing model based on a nonlocal continuum theory of peridynamics is presented and applied to the fracture propagation problem. It is shown that this modeling approach provides an alternative to finite element and finite volume methods for solving poroelastic and fracture propagation problems and offers some clear advantages. In this paper we specifically investigate the interaction between a hydraulic fracture and natural fractures. Current hydraulic fracturing models remain limited in their ability to simulate the formation of non-planar, complex fracture networks. The peridynamics model presented here overcomes most of the limitations of existing models and provides a novel approach to simulate and understand the interaction between hydraulic fractures and natural fractures. The model predictions in two-dimensions have been validated by reproducing published experimental results where the interaction between a hydraulic fracture and a natural fracture is controlled by the principal stress contrast and the approach angle. A detailed parametric study involving poroelasticity and mechanical properties of the rock is performed to understand why a hydraulic fracture gets arrested or crosses a natural fracture. This analysis reveals that the poroelasticity, resulting from high fracture fluid leak-off, has a dominant influence on the interaction between a hydraulic fracture and a natural fracture. In addition, the fracture toughness of the rock, the toughness of the natural fracture, and the shear strength of the natural fracture also affect the interaction between a hydraulic fracture and a natural fracture. Finally, we investigate the interaction of multiple completing fractures with natural fractures in two-dimensions and demonstrate the applicability of the approach to simulate complex fracture networks on a field scale.
A New Tool for Multi-Cluster & Multi-Well Hydraulic Fracture Modeling
Authors: Zhai Zongyu , Fonseca Ernesto , Azad Ali , Cox Barbara 
Published: February 2021

Abstract
Unconventional gas and tight oil reservoirs require cost-effective fracturing technologies to optimize cost versus productivity and ensure viable commercial development. Horizontal wells together with completion techniques to initiate transverse fractures have been the key to unlocking these vast resources. Variables in the completion design for fracture stimulation in a horizontal well include injection rate, fluid properties, solid loading, well spacing, cluster spacing, and the sequence and timing of pumping stages between wells in a multi-well pad.
An optimized design is critical to improve hydrocarbon production and to reduce the cost. However in current practice, multi-cluster and multi-well design is primarily based on progressive experience and is typically of standardized design in a given area (e.g. the clusters and wells are evenly distributed). This is due in part by the limitations of existing hydraulic fracturing simulators, including: 1. An assumption of planar fractures; 2. Fracture interference within and among stages and adjacent wells is ignored; and 3. Numerical instability when modeling systems with large dimensionless toughness e.g. slick water injection into high-toughness rock.
This paper describes an emerging non-planar 3D fracturing software package with the capability to simulate interference between hydraulic fractures propagating from multiple clusters and multiple wells. Thus, both simultaneous and sequential multiple fracture propagation can be modeled. Furthermore, numerical instability with large dimensionless toughness is solved and makes it possible to predict the fracture geometry equally well for slick water fluids. The case study in this paper shows how fracture interference and proppant distribution occurs within a stage as well as between well and stages. The simulated fracture patterns can be matched with field microseismic data and the simulated pressure trend is in agreement with field operational data. Using this approach, multi-cluster and multi-well designs can be optimized in a manner not previously possible.
Applications of Geomechanics to Hydraulic Fracturing - Case Studies from Coal Stimulations
Authors: Pandey Vibhas J. 
Published: February 2021

Abstract
Modern hydraulic fracture treatments rely heavily on the implementation of formation property details such as in-situ stresses and rock mechanical properties, in order to optimize stimulation designs for specific reservoir targets. Log derived strain and strength calibrated in-situ properties provide critical description of stress variations in different lithologies and at varying depths. From a practical standpoint however, most of the hydraulic fracture simulators that are used for fracturing treatment design purposes today can accommodate only a limited portion of a geologic-based rock mechanical property characterization which targets optimal data integration thus resulting in complexity. By using examples from hydraulic fracture stimulations of coals in a complex but well characterized stress environment (Surat Basin, Eastern Australia) we distil out the reservoir rock related input parameters that are determinants of hydraulic fracture designs and identify those that are not immediately used. In order to understand the impact on improving future fracture stimulation designs, the authors present workflows such as pressure history matching of fracture stimulation treatments and the calibration process of key rock mechanical parameters such as Poisson's ratio, Young's modulus, and fracture toughness. The authors also present examples to discuss synergies, discrepancies and gaps that currently exist between ‘geologic’ geomechanical concepts (i.e. variations in the geometry and magnitude of stress tensors and their interaction with pre-existing anisotropies) in contrast to the geomechanical descriptions and concepts that are used and implemented in hydraulic fracturing stimulations.
In the absence of a unifying hydraulic fracture design that honors well established geologic complexity, various scenarios that allow assessing the criticality, usefulness and weighting of geologic/mechanical property input parameters that reflect critical reservoir complexity, whilst maintaining applicability to hydraulic fracturing theory, are presented in the paper. Ultimately it remains paramount to constrain as many critical variables as realistically and uniquely possible. Significant emphasis is placed on reservoir-specific pre-job data acquisition and post-job analysis. The approach presented in this paper can be used to refine hydraulic fracture treatment designs in similar complex reservoirs worldwide.
Characterizing the Stimulated Reservoir with a Hydraulic Deformation Index Using Tiltmeter-based Surface Microdeformation
Authors: Nanayakkara Asanga S. , Roadarmel William H. , Marsic Scott D. 
Published: February 2021

Abstract
Surface microdeformation monitoring is a fracture diagnostic technology that uses measurements of surface deformation morphology, on the micrometer scale, to geomechanically invert for dislocations and volumetric changes at reservoir depth. Surface microdeformation monitoring is a mature technology that has been successfully applied for more than two decades, using measurements from surface tiltmeter arrays. The conventional deliverables of this fracture-mapping technology have historically been limited to orientation (azimuth and dip) and the volumetric ratios of main fracture components.
This paper introduces a new technique for mapping and characterizing the areal distribution of the main fracture components using surface tiltmeter measurements. The areal distribution of main fracture components is additionally characterized with a hydraulic deformation index (HDI). HDI aids the identification of rock volumes having higher or lower volumetric fracture activity, and thus may provide additional insight into approximate fracture dimensions, productive stimulated reservoir area and where proppant could be located.
This paper describes the process of producing stimulated reservoir characterization (SRC) results with HDI using surface tiltmeter measurements. Synthetic data examples as well as SRC and HDI results derived by applying the new technique to a horizontal well hydraulic fracture stimulation project in the Viking sandstone formation are presented. The paper also includes comparison of SRC and HDI results with downhole microseismic results of the Viking sandstone project.
Surface microdeformation does not require an observation well. Once a precision surface tiltmeter array is installed, it can be used to diagnose multiple stages within the covered area. Hence, the new technique provides an economically viable fracture diagnostic solution for many unconventional reservoir stimulations, such as massive multistage horizontal well hydraulic fracture treatments.
Exploring the influence of the North Pacific Ocean Rossby wave sources on interannual variability of summer precipitation and surface temperature over the Northern Hemisphere.
Authors: Fuentes-Franco Ramon , Koenigk Torben , Docquier David , Graef Federico , Wyser Klaus 
Published: February 2021

Abstract
The influence of Rossby wave sources (RWS) emitted on the Northeastern Pacific Ocean in the Northern Hemisphere during summer is analysed in the ERA5 reanalysis and new large ensemble performed with the EC-Earth3 model. Using extreme years composites of precipitation, surface temperature, geopotential height, we found a causal influence of the Rossby waves generated over the Northeastern Pacific Ocean, on a global climate response. Both the reanalysis ERA5 and the EC-Earth3 model show that RWS triggers wave-like patterns arising from the upper troposphere Northeastern Pacific region. We show that an increased Rossby wave sources intensity is related with negative temperature anomalies over western North America, and positive temperature anomalies over eastern North America concurrently increased precipitation over Northern Europe during summer and sea-ice concentration decrease in the Arctic. We also show that the North Atlantic plays a very important role hindering or permitting that Rossby waves generated in the Pacific reach the Atlantic and modulate the atmospheric conditions over Europe. Such conditions were found in ERA5 and SMHI-LENS during colder and icier conditions over the North Atlantic.
Optimizing sludge dewatering with an alternate pressure and electric field
Authors: Li Yunyi , Huang Xinmiao , Wei Ying , Liu Yangsheng 
Published: February 2021

Abstract
Sludge dewatering is a prerequisite for the subsequent utilization of sludge. However, the existing mechanical dewatering cannot achieve satisfactory water content (< 60%). Herein, pressure and electric dewatering in alternate operation (P/EDWalt) was proposed to improve dewatering efficiency. Compared with conventional simultaneous mode, P/EDWalt performed better in sludge dewatering. Its optimal dewatering conditions were voltage of 30 V for 20 min in two electric dewaterings, and pressure of 0.04, 0.07 and 0.10 MPa in three pressure dewaterings. Such conditions, the water content of sludge was reduced from 83.7% to 53.3%, the dewatering efficiency was 36.3%, and the energy consumption was 0.138 kWh/kgtotal removed water. These phenomena such as electroosmosis, the ohmic heating and electrophoresis facilitated the removal of water in sludge, and the dewatered sludge has good reusability in incineration, landfill and agriculture. Therefore, P/EDWalt could serve as a promising method for the sludge dewatering.
An Unusual Case of chest wall Glomus Tumor presenting with axillary pain: a case report and literature review
Authors: Zanjani Leila Oryadi , Nia Bahman Shafiee , Vosoughi Farzad , Mirzaian Elham , Aghaghazvini Leila , Arabzadeh Aidin 
Published: February 2021

Abstract
Background: Glomus tumor is an uncommon soft tissue tumor. However, as the tumor causes significant disability, its early diagnosis is essential. It involves subungual areas of fingers and toes in most cases, and its extra-digital involvement is rarely seen. To the best of the authors' knowledge, only a few chest wall involvement cases have been reported in the literature. Case presentation: In this paper, we describe a 63-year-old patient with a chest wall glomus tumor presented with axillary paroxysmal pain and limitation in his shoulder range of motion that had been missed for nearly 15 years. His symptoms were relieved immediately following surgical excision.Conclusion: Glomus tumors may involve any part of the human body. It is curable with surgical excision in most cases. Therefore, a correct early diagnosis has paramount importance. A high index of suspicion is needed for early diagnosis, especially when the tumor involves uncommon anatomic areas.
Effects of autoantibody against M2-muscarinic acetylcholine receptor in peripartum cardiomyopathy patients on digoxin additional to standard treatment
Authors: Ma Guiling , Chen Long , Yue Yin , Liu Xiyan , Wang Yidan , Shi Cheng , Song Fei , Shi Wei , Lo Yingshih , Zhang Lin 
Published: February 2021

Abstract
Objectives

To evaluate the effects of autoantibodies against the M2-muscarinic receptor (anti-M2-R) on digoxin additional to standard treatment in peripartum cardiomyopathy (PPCM) patients.
Methods

107 PPCM patients, receiving digoxin and standard treatment regimen for HF, were enrolled between January 1998 and June 2020, who were separated into anti-M2-R negative (n = 59) or positive (n = 48) group according to the anti-M2-R reactivity. Echocardiography and serum digoxin concentration (SDC) were performed regularly. All-cause mortality, cardiovascular mortality and re-hospitalization for heart failure were compared.
Results

103 patients completed the final data analysis, including 46 in the anti-M2-R (+) group and 57 in the anti-M2-R (-) group. Heart rate of the positive group was lower than that of the negative group at baseline (102.7 ± 6.1 vs. 96.0 ± 6.4, p < 0.001). The initial SDC of patients in the positive group was higher than that of patients in the negative group with the same dosage of digoxin (1.25 ± 0.45 vs. 0.78 ± 0.24 ng/mL, p < 0.001). Anti-M2-R (-) patients had better tolerance to metoprolol (38.4 ± 4.6 mg b.i.d. vs. 27.4 ± 5.0 mg b.i.d., p < 0.0001) and digoxin (0.12 ± 0.02 mg/day vs. 0.08 ± 0.04 mg/day, p < 0.0001). The improvement of heart function was obvious in the first year, especially in the first half. Furthermore, anti-M2-R (-) patients showed better improvement than that in anti-M2-R (+) patients. Re-hospitalization for heart failure was decreased in the negative group, but not of all-cause or cardiovascular mortality.
Conclusions

Anti-M2-R maybe a predictor for vagus nerve overactivation and is associated with poor response to digoxin in PPCM patients.
Development and Multicenter Assessment of a Reference Panel for Clinical Shotgun Metagenomics for Pathogen Detection
Authors: Liu Donglai , Xu Teng , Zhou Haiwei , Yang Qiwen , Mo Xi , Shi Dawei , Ai Jingwen , Zhang Jingjia , Tao Yue , Wen Donghua , Tong Yigang , Ren Lili , Zhang Wen , Xie Shumei , Chen Weijun , Xing Wanli , Zhao Jinyin , Wu Yilan , Meng Xianfa , Ouyang Chuan , Jiang Zhi , Liang Zhikun , Tan Haiqin , Fang Yuan , Qin Nan , Guan Yuanlin , Gai Wei , Xu Sihong , Wu Wenjuan , Zhang Wenhong , Zhang Chuntao , Wang Youchun 
Published: February 2021

Abstract
Background Clinical shotgun metagenomics for pathogen detection has been used in diagnosing infectious diseases. However, its technical assessments have been limited to reference standards by individual labs, single experimental workflow and laboratory.Results Here we reported the design and development of a set of reference reagents and reporting metrics dedicated for clinical metagenomics by the National Institutes for Food and Drug Control (NIFDC) of China, and a joint evaluation study including 17 independent laboratories in cross-workflow and cross-platform settings. Our results showed that the performance of metagenomic assays was significantly impacted by the factors of microbial types, host context, and read depth, thus highlighting the importance to take these factors into consideration when designing reference reagents and benchmarking assays. Through this study, we found false positives to be a common challenge across centers, and considerable site and library effects to limited the assay’s quantitative value. Our multicenter study also provided practical guidance of performance that laboratory-developed shotgun pathogen metagenomics tests should aim to detect microbes at 500 CFU/mL (or copies/mL) in clinically relevant host context (10^5 human cells/mL) within a 24h turn-around time, and with a read depth of 20M reads or lower. This collaboration work provided a unique resource comprising nearly 600 billion reads (>5Tb) for technical evaluation in clinical and regulatory settings.Conclusion We demonstrated that the performance of metagenomic assays was significantly impacted by the microbial type, the host context and read depth, which emphasizes the importance to consider these factors when designing reference reagents and benchmarking studies. Across sites, workflows and platforms, false positive reporting and considerable site/library effects were common challenges to the assay’s accuracy and quantifiability. Our study also suggested practical guidance of performance that laboratory-developed shotgun pathogen metagenomics tests should aim to detect microbes at 500 CFU/mL (or copies/mL) in clinically relevant host context (10^5 human cells/mL) within a 24h turn-around time, and with a read depth of 20M reads or lower. This collaboration work provided a unique resource comprising nearly 600 billion reads (>5Tb) for technical evaluation in clinical and regulatory settings.