bluuebunny/crossref_metadata_2025 huggingface dataset:
Utilizing Multimedia Technology in Digital Learning Content Development
Authors: Tuharea Jumiati , Yanuarsyah Iksal , Nitin Mahon , R Muh Rafli , Jie Lie , Jixiong Cai
Published: September 2023

The development of information and communication technology is growing rapidly. Many positive impacts are obtained, especially in the field of education. Teachers and students find it easy to do the learning process in the classroom. If they use technology in digital learning. Access to new knowledge, information from various parts of the world, learning methods that suit student needs, and others can be reached with just one tap of the finger. It is so easy to compete in this globalization era. One of them is by utilizing multimedia technology in the development of digital learning content, so that if utilized optimally, it will get great benefits. The results of content creation are more interesting and favored by the audience. The purpose of this research is to facilitate the development of digital learning content by utilizing multimedia technology as much as possible, so that learning objectives for students can be achieved properly and optimally. For example, by creating educational content about one of the learning materials on YouTube which contains direct explanation by the teacher in an interesting place. And the content is supported by features that are interesting and not boring. The method used in this research is quantitative method. Data obtained through distributing questionnaires to students. The questionnaire was created by utilizing Google form. The results of this study explain that utilizing multimedia technology properly in creating digital learning content will provide benefits for teachers and students in the learning process. The conclusion of this study is that the utilization of multimedia technology has a positive influence and provides space for teachers to provide digital learning content easily and creatively. The limitation of this study is that researchers only conducted research at the school or madrasa level which in fact requires the use of multimedia technology in learning.
The Effectiveness of Using Digital-Based Teaching Materials on Craftsmanship and Entrepreneurship Learning Outcomes of Class XI Muhammadiyah High School Students
Authors: Mustika Mustika , M Usman , Takdir Muhammad , Hermansyah Sam , Kahar Abdul
Published: September 2023

This study uses a quantitative method with the type of experimental research that aims to determine the effectiveness of using Flip Books on the results of Craft and Entrepreneurship learning for class XI SMA Muhammadiyah Pangsid, Sidenreng Rappang Regency.The population of this study were all 27 students of class XI SMA Muhammadiyah Pangsid, and the sample of this study was 27 people using the total sampling technique, namely by taking the overall sample. The data collection techniques used were documentation techniques, test techniques, and questionnaire techniques. The indicators of effectiveness in this study are based on Sinambela's theory (2006), the three indicators of effectiveness are: learning completeness, timeliness, and student responses. Learning outcomes are a measure of one's success. The results of this study indicate that the average posttest score is 88.0% higher, while the pretest result is 70.9%. The results showed that the use of Flip Books on the learning outcomes of crafts and entrepreneurship in class XI SMA Muhammadiyah Pangsid was declared effective.
Threeyasa Group Banyuwangi Company Profile Design
Authors: Arbekti Arman Shevti , Wang Yuanyuan , Zou Guijiao
Published: September 2023

In this era of industrial revolution, it is undeniable that development progress is increasing to meet human needs in carrying out their activities. One of the groups that play an important role in this field is a company that focuses on tourism services. ThreeYasa Group is a Travel Agency business that was founded in 2020. Threeyasa Group is still fairly conventional in conducting promotions and communication with customers, namely utilizing the exchange of short messages only. ThreeYasa Group needs a digital platform to introduce its business to a wider audience.   Company Profile is an effective promotional media design that can attract consumer attention and build cooperation with business people. Designing a company profile can make it easier for the owner to manage his business and make his business more dynamic. software development in making a company profile using the waterfall model. system analysis using interviews and observation methods. in visualizing actors with the system using usecase diagrams implemented using StartUML software. while coding uses the php programming language with Notepade++ software.  Testing the system using Black Box Testing.
Interactive Learning Media Application For The Introduction Of Human Needs In Children Aged
Authors: Teresia Vany , Jie Lie , Jixiong Cai
Published: September 2023

Early childhood education is a form of education that focuses on establishing the basis for significant physical growth and development, such as body growth and motor development. Children begin to develop the ability to think, learn, remember and understand basic concepts. This research aims to produce an animated application for the introduction of human needs in children for their congnitive development.  In the design process using Flowchart diagram to create an overview of how the process in the interactive learning media application. Storyboard is used for an overview of the appearance and workings of interactive learning media applications. There are several choices of materials such as food, drink, clothing, health, hygiene and safety. All materials are equipped with sound images and attractive displays. Flowchart is used to display the workflow, from the start to the stage of selecting interactive learning media application materials. The application contains material that already covers the curriculum used by PAUD schools in general. Interactive learning media applications help early childhood in learning about human needs.
Product Development of Unique Clothing Learning Media to Stimulate Fine Motor Skills of 4-5 Years Old Children
Authors: Nopiyanti Heni , Tabroni Imam , Barroso Uwe , Intes Amina
Published: September 2023

The purpose of this study was to create a learning model product in the form of unique clothing to stimulate fine motor skills of children aged 5-6 years in Purwakarta. The research method used a mixed method with a research and development (R&D) design. The research process starts from making a product design design using media with materials around, in the form of used gallon bottles, design validation, revision, making products, limited product trials, making products, stage 1 product revision, main field trials, revision 2, operational field trials, product revision 3, dissemination and product marketing. The results of research on the development of unique clothing learning models to stimulate fine motor skills are more creative and innovative learning models. The results of the research in the form of children's fine motor movement skills are getting better and children's fine muscles are getting stronger and more skillful. This unique clothing model gives children the interest to be able to play it so that fine motor skills are stimulated in a fun way. The technique supports children's understanding of attitudes, motivation and curiosity towards psychomotor activities (fine motor). This broad trial was conducted three times and experienced good improvement, so it is hoped that this model can be disseminated to PAUD institutions in Purwakarta and surrounding areas.
Number Board Media To Stimulate Symbolic Thinking Ability In Children 5-6 Years Old
Authors: Saripah Ipah , Tabroni Imam , Armando Gonzales , Maria Lucas
Published: September 2023

The child will experience a very important golden period and cannot be missed until he is 3 years old. The reason is that during these times, children's cognitive abilities are still growing and developing rapidly. In fact, about 80% of children's cognitive skills occur optimally in the first 3 years of life, and up to 90% of their abilities will continue to develop until they reach the age of 5 years. Media is a tool that can be used as an intermediary in stimulating all aspects of development in early childhood, both aspects of moral and religious values, physical-motor aspects, language aspects, social-emotional aspects and cognitive aspects. To stimulate all aspects of early childhood development cannot be separated from learning media because for early childhood learning is done through playing using learning media both real media, audio media, visual media, surrounding environmental media and audio visual media, so that learning activities for children early age runs effectively. This article will discuss how the influence of the number board media in stimulating the symbolic thinking skills of children aged 5-6 years in Sumurugul Village
System for quantitative diagnosis of COVID-19 associated Pneumonia based on Superpixels with deep learning and chest CT
Authors: Tetila Everton Castelão , Bressem Keno Kyrill , Astolfi Gilberto , Sant’Ana Diego André , Pache Marcio Carneiro Brito , Wirti Junior Gelson , Barbedo Jayme Garcia Arnal , Pistori Hemerson
Published: September 2023

COVID-19 is a disease caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that can lead to complications such as acute respiratory distress syndrome, acute heart injury and secondary infections in a relatively high proportion of patients and, consequently, lead to significant mortality. The definitive diagnosis of COVID-19 is performed by real-time Polymerase Chain Reaction (RT-PCR). However, as RT-PCR results usually take longer to be completed than computed tomography (CT), the latter has had an important role in the detection of patients infected with COVID-19. A rough estimate of the extent of lung involvement by the disease is also important and considered an additional criterion for deciding on discharge or hospitalization. Recent research has adopted deep neural networks and other machine learning approaches to detect the presence of lung infection caused by COVID-19. However, the extent of lung involvement (volume) caused by the disease has been only superficially investigated. In this work, we created an end-to-end computer vision system to automatically quantify the Percentage of Infection (POI) in chest CT images of COVID-19 cases confirmed by laboratorial analysis. We evaluated the performance of three well-known deep neural networks, trained using three different strategies: (1) no transfer learning with randomly initialized weights; (2) transfer learning using with ImageNet weights without fine-tuning; and (3) transfer learning with weight fine-tuning. Data augmentation and dropout were used during training to reduce overfitting and increase the generalization capacity of the models. Our approach consists of segmenting a chest CT with the SLIC Superpixels method and classifying each segment (superpixel) into a specific class (COVID or non-COVID). We used the weights of the best deep neural network to classify the superpixels and quantify the COVID-19 infection by calculating the POI on chest CT. The results indicate that deep learning models can be successfully used to support radiologists in the quantitative diagnosis of lung infection caused by COVID-19, reaching an accuracy of up to 98.4% with Inception-Resnet-v2 architecture.
Organizational Innovation Theory: A description of the main schools and their contributions by author
Authors: Mejia-Trejo Juan
Published: September 2023

It is a characteristic of the condition of the human being, its sense of social interrelation since there is historical evidence that prehistoric person grouped and organized them to achieve various activities such as hunting, protection, war, and even selecting a partner for the consolidation of their clans or tribes. Once sedentary, it required more sophisticated forms of organization to practice agriculture and cattle raising and build their homes, cities, and diverse infrastructure. However, even though the usefulness of organizing has been evident to humanity, it was not until the 20th century which various thinkers, particularly in the area of ​​psychology, ventured into the deliberation of its design, implementation, as well as the causes and effects that have different organizational structures to use, more than anything, in the business field. In this way, this work is addressed to those who are insiders and outsiders to organizational innovation who need to know about the various structures that have been adopted throughout history and have a notion of how both the external and internal environment has influenced their development. Its definition. They are presented in various chapters so that it is known, in an approximate chronologically, what each current of organizational thought consists of, as well as learning the primary authors and their contribution works with discussions of their scope and limitations. Since the organization is an activity that is the product of the habits and customs that prevail in different periods of history, it is expected that the organizational models presented here will continue to evolve; In fact, it stands out that there is no single organizational innovation structure, but that it responds to a series of factors that, as will be discussed in the book, present themselves in various forms, according to the human group that analyzes them and their interests. You will be free to adopt to the best of your ability.
O SAMBA ENREDO CAPIXABA NA PERSPECTIVA DA CARNAVALIZAÇÃO EM BAKHTIN: DIÁLOGOS POSSÍVEIS
Authors: Da Silva Adriana Souto Tavares , Gomes Antônio Carlos , De Souza Janderson Batista , De Carvalho Letícia Queiroz
Published: September 2023

O presente artigo tem como objetivo analisar a carnavalização da cultura popular no contexto das escolas de samba capixabas, sobretudo pela compreensão do samba enredo sob o viés bakhtiniano, a partir do diálogo com as concepções de Mikhail Bakhtin e do Círculo, destacando-se aquelas presentes nos livros A cultura popular na Idade Média: o contexto de François Rabelais (2008) e Problemas da poética de Dostoiévski (2010).  Por meio de um cotejo teórico, à luz da perspectiva dialógica da pesquisa em Ciências Humanas, pretendemos ampliar as possibilidades de trabalho com as letras do samba enredo capixaba, estabelecendo articulações entre a linguagem carnavalizada, a cultura popular e a participação ativa nessas festividades, de modo a contribuir para que os indivíduos se sintam parte de um grupo, fortalecendo os vínculos sociais.
Fire engineering and structural design – common misconceptions and good practice
Authors: Warren Holly , Quinn Olivia , Byrne Emma , Leach Jon
Published: September 2023

This paper on four common misconceptions in fire engineering and structural design was written as a collaboration between AECOM fire engineers and structural engineers.
Analysis of Principal Managerial Skills in State Senior High Schools
Authors: Erisa Vivit , Mahmud Hilal , Marwiyah St. , Rustan Edhy
Published: September 2023

This study aims to analyze the implementation of the principal managerial skills, internal and external factors that contribute, and their impact on improving the quality of education in state senior high schools in Palopo, Indonesia. This research is field research using the mixed method approach. Data was obtained through questionnaires, interviews, observation, and documentation studies. The mapping of school positions was analyzed using the IFE (Internal Factors Evaluation) matrix and EFE (External Factors Evaluation) matrix. The study results show that the principals implement managerial skills, namely conceptual, interpersonal, and technical skills, to improve education quality. The results of the analysis of the internal (Strengths and weaknesses) and external factors (Opportunities and Threats) evaluation show that the strengths possessed by each school can overcome its weaknesses and are very responsive in overcoming threats in improving the quality of education. The implementation of principal managerial skills has a positive impact on improving the quality of education.
Forensic Entomological Importance of “Hairy Maggot Blowfly”: A Study in Reference to Kerala, India
Authors: Mathew Madona , V. Jaseel Abdul Kader
Published: September 2023

In order to highlight the scopes in entomology, this study aims to determine the usefulness and applicability of forensic entomology from an Indian perspective, to develop an understanding of insect lifecycle, awareness of beneficial insects, understanding of forensic entomology, and increase critical thinking application. In situations where the body has been dead for a while, forensic entomology is quite helpful. After a few days, bug evidence is frequently the most reliable and, in some cases, the only way to determine how long has passed after death. The life cycle of Chrysomya rufifacies was examined in the afore mentioned study at Kerala, India, under a room temperature (dry) 24-280C.
Laboratuvarımızda Çalışılan Prenatal Tarama Testlerinde Ölçüm Belirsizliği
Authors: Demir Leyla , Aksun Saliha
Published: September 2023

Amaç: Ölçüm belirsizliği hem bir yöntemin amaca uygunluğu hem de bir laboratuvarda elde edilen analitik sonuçların güvenilirliği için önemli bir göstergedir. ISO 15189 gibi akreditasyon süreçleri de laboratuvarlardan ölçüm belirsizliği için belirlenmiş bir yöntemleri olmasını ve istendiğinde ölçüm belirsizliği sonuçlarını sağlamasını beklemektedir. Bu çalışmada amacımız birinci ve ikinci trimester prenatal tarama testlerinde kullanılan biyokimya parametrelerinin ölçüm belirsizliğini hesaplayıp bu değerleri total izin verilebilir hata oranları ile karşılaştırmaktır.
Gereç ve Yöntem: Laboratuvarımızda prenatal tarama testlerinde kullanılan gebelikle ilişkili plazma protein-A (PAPP-A), serbest beta insan koryonik gonadotropini (sß-hCG), alfa feto protein (AFP), insan koryonik gonadotropini (HCG) ve unkonjuge estriol (uE3) parametreleri için ölçüm belirsizliği hesaplandı, Nordest kılavuzunda yer alan Avrupa akreditasyon rehberi ve Eurolab teknik raporu ISO 21748 rehberinden faydalanarak hesaplamalar yapıldı. Bu hesaplamalarda iç kalite kontrol ve dış kalite kontrol sonuçları kullanıldı.

Bulgular: Ölçüm belirsizlik değerleri AFP için %16.4, sβ-hCG için %17.04, HCG için %27.84, PAPP-A için %18.54 ve uE3 için %22.52 olarak bulundu. Çalışmamızda en yüksek ölçüm belirsizliği HCG ve uE3 parametreleri için bulunurken en düşük ölçüm belirsizliği ise AFP için bulundu.

Sonuç: Laboratuvarımızda prenatal tarama testlerine ait biyokimyasal parametrelerin ölçüm belirsizlikleri hesaplanmıştır. HCG, PAPP-A ve uE3 testlerinin ölçüm belirsizliği yüksek bulunmuştur, Özellikle risk açısından eşik değere yakın prenatal tarama testlerinde ölçüm belirsizliğinin dikkate alınarak sonuçların yorumlanması önemlidir.
Pigeon Pea Green Manuring and Nitrogen Fertilization Increase Agronomic Efficiency by Improving Yield and Ear Characteristics of Maize
Authors:   Department of Field Crops, Faculty of Agriculture, Isparta University of Applied Sciences, Turkey, Nawaz Haq
Published: September 2023

Green legume incorporation is an encouraging, at least unfinished, substitute for chemical fertilizers, particularly for nitrogen (N). The experiment was conducted in an RCB design with a split plot arrangement replicated four times. Pigeon pea green manuring (GM) of 3.4, 6.3 and 7.3 t ha-1 at pre flowering (GM1), at flowering (GM2) and post flowering (GM3) were assigned to the main plots, respectively, and nitrogen levels (N) (0, 70, 100 and 130 kg N ha-1) were allotted to the subplots. Results showed that GM2 significantly improved plant height (183 cm) and leaf area (393.6 cm2). Whereas, GM1 significantly enhanced biological yield (9826 kg ha-1), grain yield (3500 kg ha-1), thousand grain weight (203.6 g), grain ear-1(319), ear length (18 cm) and ear diameter (11.4 cm) as compared to GM2. Similarly, nitrogen application at the rate of 130 kg ha-1 resulted in taller plants, higher leaf area, thousand grain weight, biological and grain yields, harvest index, grains ear-1, ear height, length, weight and diameter than other N levels. The agronomic efficiency (AE) was significantly increased by 13.8 kg kg-1 and 11.8 kg kg-1 at GM1 and 70 kg N ha-1, respectively. It was concluded from the outcomes of the study that pigeon pea GM at pre flowering stage and 130 kg N ha-1 improved maize crop production.
Experimental Analysis of Rockbolt Plate Strength Through Static and Dynamic Testing
Authors: MacDonald D. , Gaines S. , Render W.
Published: September 2023

A typical ground support system designed to safely excavate mine openings in rock consist of rockbolts, rockbolt plates, steel mesh, structural support lines, and shotcrete. The rockbolt plate, which connects the embedded rockbolt to the surface support, is a crucial part of a ground supporting system and is often the weakest link. Matching the correct embedded rockbolt to the rockbolt plate is crucial for proper ground support system interaction. If the selected plate is too weak, it will deform and will prevent full rockbolt yielding. If the plate is too strong, the system will take a lower cumulative load due to the lost energy dissipation potential of the plate and there will be no indication of rockbolt load due to the hindering of plate deflection. The rockbolt plate should deform during the yielding phase of the rockbolt, and fail after the reinforcing element. The ground support system must accommodate static and dynamic loading conditions and mechanical properties must be characterized to optimize rockbolt density and safety factor. CanmetMINING has developed a static and dynamic rockbolt plate testing regime using industry standards and innovative testing methods. The static testing methods are modified versions of standardized deflection tests. The dynamic testing methods were developed by CanmetMINING and include novel testing methodology. This paper describes the instrumentation and data acquisition methods, testing methodology, data processing method, and analysis of the static and dynamic test results from the tests.

INTRODUCTION

As the demand for critical minerals increases, there is additional pressure on mining operations to exploit new ore reserves, often in areas with more difficult ground conditions (Plouffe et al., 2008). In some cases, these orebodies are now found at depth, which poses additional ground control challenges due to higher in-situ stress conditions. To mitigate ground control instability, mining and ground control engineers carefully select appropriate reinforcement systems that may include rockbolts, mesh, and/or shotcrete (Potvin et al., 2010).

At CanmetMINING's Ground Support Testing Laboratory in Ottawa, Ontario, Canada, linear reinforcement elements (i.e., rockbolt systems) can be evaluated under static and dynamic conditions. This detailed characterization of ground reinforcement elements is important for design engineers to understand the behavior of the ground reinforcement and therefore specify the appropriate reinforcement to counteract anticipated failure mechanism(s). This current research program focusses on the development of a method for evaluating rockbolt plate response under static and dynamic loading conditions for the purpose of improving plate characterization and contributing to improved rockbolt performance.
Longwall-Induced Deformations and Shale Gas Well Casing Stresses: Engineering Principles
Authors: Su Daniel W. , Zhang Peter
Published: September 2023

This paper summarizes important findings from the ongoing National Institute for Occupational Safety and Health (NIOSH) gas well stability research. Over the past seven years, field instrumentation results from NIOSH case studies and active mine-by case studies indicate that, under shallower covers, the measured horizontal displacements within the longwall abutment pillar are one order of magnitude higher than those measured under deep cover. Longwall-induced horizontal displacements occur along weak-to-strong rock interfaces; the sharper the bending stiffness contrast across the interfaces, the larger the longwall-induced horizontal displacements. Longwall-induced vertical compressions under shallower covers are, on the other hand, one order of magnitude lower than those under deep covers. Subsurface strata dip may magnify or reduce longwall-induced horizontal displacements. Uncemented production casings serve to uncouple longwall-induced deformations and stresses from the production casing. A case study is presented to illustrate the importance of leaving the production casing uncemented.

INTRODUCTION

Since 2003, over 1,800 unconventional shale gas wells have been drilled through active and future Pittsburgh Seam coal reserves in Pennsylvania, West Virginia, and Ohio. These unconventional gas wells, whether tapped into the Marcellus or Utica formations, contain very high gas pressure and volume. Strata deformations associated with underground longwall coal mining could induce stresses and deformations in the shale gas well casings, which in certain situations could compromise the mechanical integrity of the production, intermediate, and coal protection casings. Damaged well casings could potentially introduce high-pressure, high-volume explosive gas into underground mine workings to jeopardize underground miners’ safety and health.

To provide critical scientific data to the stakeholders, which includes the Mine Safety and Health Administration (MSHA), the Pennsylvania Department of Environmental Protection (PADEP), the West Virginia Department of Mine Safety (WVDMS), the Ohio Department of Natural Resources (OHDNR), coal operators, and gas operators, NIOSH initiated a research program in 2016 to evaluate the effects of longwall-induced deformations on shale gas well casing stability under deep as well as shallow covers. The effects of longwall-induced subsurface deformations on shale gas well casing stability under deep cover, under medium cover, and under shallow cover were published previously (Su et al., 2018a and 2018b; Su et al., 2019a and 2019b; Su et al., 2020; Zhang et al., 2020; Su and Zhang, 2021; Su et al., 2021). This paper focuses on a case study that illustrates the importance of leaving the production casing uncemented.
Impact of Drilling Mud Intrusion on Borehole Stability in Naturally Fractured Rocks: A Coupled DEM-DFN Investigation
Authors: Wei Yaoran , Feng Yongcun , Yang Tianyu , Tan Zhenlai , Dai Zhiyue , Li Xiaorong
Published: September 2023

Borehole instability in naturally fractured rocks poses significant challenges to drilling. However, the weakening of fracture strength due to mud intrusion was not considered in most existing borehole stability analyses, which may yield significant errors and misleading predictions. In addition, the fracture distribution was oversimplified. In this paper, the impacts of mud intrusion on borehole stability in fractured rocks under anisotropic stress states are investigated using a coupled DEM (distinct element method) and DFN (discrete fracture network) method. A simplified, but reasonably realistic approach is developed to take into account the weakening of fracture strength due to mud intrusion. The results show that mud intrusion and associated weakening of fracture strength and hydro-mechanical coupling effect cause more shear failure of natural fractures and rocks, explaining why the increase in mud weight worsens borehole stability during overbalanced drilling in fractured rocks. This study provides a directly quantitative prediction method of borehole instability in naturally fractured formations based on the consideration of mud intrusion and its weakening of fracture strength.

INTRODUCTION

Borehole instability is a phenomenon that the borehole size and its structural integrity can not be maintained in the openhole interval. Maintaining a stable borehole is of great importance because related instability problems pose negative influences on the drilling schedule and costs, and even lead to the abandonment of the well (Chen et al., 2003; Zhang, 2013; Li et al., 2019). Various factors that affect borehole stability were investigated to explain the mechanism involved with wellbore collapse such as mud weight, in-situ stress, wellbore trajectory, rock properties, and failure criteria (Zhao et al., 2012; Mansourizadeh et al., 2016; Liu et al., 2021; Li et al., 2019; Zhang et al., 2020; Li et al., 2022; Aslannezhad et al., 2021). Both theoretical and field data have indicated that an appropriate increase in mud weight does benefit wellbore stability in continuous media (Salehi et al., 2010; Fan et al., 2020; Ibrahim, 2021; Motahari et al., 2022). However, compared with non-fracture formation, increasing mud weight may negatively impact wellbore stability in naturally fractured rocks (Santarelli et al., 1992; Yamamoto et al., 2002). It has been demonstrated that the role of drilling mud in maintaining borehole stability should be reconsidered when drilling in fractured rock formations. In addition, the mechanism of coupling effect of in-situ stress anisotropy, natural fractures, and drilling mud intrusion on borehole stability has not been fully understood.
The Effect of Rock Heterogeneity on Fracture Initiation During Supercritical CO2 Fracturing
Authors: Yang Bing , Yang Hong , Ren Lingying , Zhu Rongting , Huang Hai , Wang Haizhu , Ni Jun , Zheng Yong , Zhang Wentong
Published: September 2023

To solve the issues during large-scale hydraulic fracturing such as massive consumption of water, formation damage and environmental contamination, etc., supercritical CO2 (SC-CO2) has been introduced as an alternative anhydrous-fracturing fluid. However, the heterogeneity of formation would have significant impact on fracture initiation. In this study, a series of tight sandstones was collected to perform SC-CO2 fracturing experiment. The effects of bedding-plane angle (BPA) and permeability of sandstone on fracture initiation are investigated. The results indicate that the initiation pressure of rock shows a fluctuating trend, it goes up firstly, then slightly goes down with the increasing of BPA. And the fracture morphology is significantly affected by the heterogeneity of rock, which are more inclined to distribute along the bedding planes. Moreover, the rocks with lower permeability have higher initiation pressure, and more complicated fractures would be induced. With the increasing of the permeability, the initiation pressure of rock reduce significantly, also the fractures morphology are gradually simplified. When the permeability reaches to 0.5 mD, the rock cannot be broken by SC-CO2 in the experimental pumping rate, but it can be fractured by water. It means that SC-CO2 as fracturing fluid is more appropriate to implement in low permeability reservoirs since its low viscosity and strong penetration. This research explores the formation adaptability and provides theoretical guidance for field application of SC-CO2 fracturing.

INTRODUCTION

Tight gas as typically unconventional reservoir, is widely distributed in China, which will play a significant role in the supplement of conventional hydrocarbon. According to the fourth oil and gas resource evaluation of CNPC, China's total onshore tight gas resources are 21.85 × 1012 m3, with 60% of the total resources in the Ordos Basin (Jia et al. 2022). Tight sandstone gas resource is usually with porosity less than 10%, in-situ permeability less than 0.1 mD, pore throat diameter less than 1 μm, and gas saturation less than 60% (Jia et al. 2012; Gong et al. 2016). These reservoirs cannot be produced directly without artificial stimulation method (Scanlon et al. 2014; Ma et al. 2015).
Three-Dimensional High Efficiency Fracturing Technology for Preventing Casing Deformation in W Deep Shale Gas
Authors: Wei Ran , Xiaobing Bian , Xudong Zhang , Bo Xiao , Nai Cao , Luo Zuo , Jinlong Du , Yuan Su
Published: September 2023

The right of W mineral cover an area of 143.77km2. As shale gas horizontal wells are prone to casing deformation by segmental fracturing, the casing deformation rate exceeds 45%, which seriously affects the production capacity construction of shale gas wells in W block. A set of techniques for high-strength balanced fracturing process in multiple clusters for preventing casing deformation in W shale gas wells has been developed, including: 1) two evaluation indexes, namely stress-strain brittleness index and vertical stress and difference index between vertical stress and minimum horizontal stress, have been added to establish W deep shale fracturing quality evaluation index plate and realize fine division of segment clusters; 2) a multi-scale fracture network fracturing numerical model for W Shale gas wells was established for the first time via Eclipese software, and key fracture parameters such as optimal fracture half-length, flow conductivity and complexity were obtained; 3) in engineering construction, a multi-cluster, small particle size and variable displacement combination injection fracturing scheme has been proposed for two injection modes: planar perforation and spiral perforation, respectively, with the objective of reducing casing.

INTRODUCTION

Shale gas, as a new unconventional natural gas resource, occupies an increasingly important position in the energy sector. The economic development of deep shale gas in the US has gone through a process of continuous exploration and testing, improvement and refinement, with some blocks now meeting the requirements for economic development. Among them, 3 deep shale gas blocks in Haynesville, Eagle Ford and Canna Woodford with burial depths of 3500-4100m have been economically developed with single well gas production of more than 5×104m3/d after segmental fracturing of horizontal wells, with an average final gas recovery of more than 1×108m3 per well and an integrated cost of less than US$12 million per well (T.Lowe et al.,2014; Mauricio et al.,2013).
Hydraulic Fracturing of a Tight Conglomerate Sample with Distributed Optical Fibre Monitoring
Authors: Wang Zhenyu , Lin Botao
Published: September 2023

In this paper, a distributed fiber-optic monitoring system is used to finely portray the effect of gravel on crack extension during a true triaxial physical simulation experiment. The experimental results show that under the control of stress difference, the obstruction effect of large-grained gravels on cracks is much higher than that of small-grained gravels on cracks. The fracture encounters the large-grained gravels to wind around the gravels mainly, and the fracture produces more microfractures within the rock. The waterfall cloud map shows a greater variation in the stretching and compression regions. When the fractures encounter small gravels, the fractures are still predominantly gravel-wrapping with some gravel penetration, and the strain distribution on the waterfall cloud diagram is uniform. When the gravel is disordered, the fracture morphology is complex and diverse.

INTRODUCTION

Conglomerate reservoirs are low porosity and low permeability. Hydraulic fracturing technology contributes to the efficient development of conglomerate reservoirs. The shape of the sewing mesh after pressing affects the final production result (Kang et al., 2020). Conglomerate reservoirs, another key development target in China after shale, have large development potential. Due to the high non-homogeneity of conglomerate, The extension of fractures in conglomerate reservoirs is affected by complex mechanisms, and characterization of fracture morphology is more difficult (Tang et al., 2022). Some scholars have conducted indoor experimental studies on the hydraulic fracture morphology of conglomerate reservoirs.

Ren et al. found that hydraulic fractures extend along the edges of conglomerate grains by large-scale physical simulations with conglomerate outcrops (Ren et al., 2023). Liu et al. used the baikouquan formation of the Mahu depression as the object of study. The indentation hardness tests found that the gravel was 5.3 times harder than matrix hardness (Liu et al., 2014). Li experimentally clarified several forms of fractures and gravels (Li et al., 2013).
Experimental Investigation of Mechanical Characteristics in Tight Sandstones by Combining Nanoindentation and AFM
Authors: Zhang Wentong , Wen Fugui , Tong Shaokai , Ren Lingying , Ni Jun , Huang Hai , Yang Bing , Ning Zhengfu , Jia Zejiang , Lyu Fangtao
Published: September 2023

Acquiring the micromechanical property of phases in tight sandstones by conventional mechanical testing is a big challenge because of the heterogeneity and complexity of mineralogical composition in sandstone systems. In this study, nanoindentation and AFM (atomic force microscope) technologies were employed to figure out the mechanical characteristic of tight sandstones. Nanoindentation results show that the average Young modulus of quartz is 72.78 GPa in tight sandstones. We found that nanoindentation needs more methods like SEM and EDS to separate the modulus of phases in tight sandstone. In contrast, AFM can easily recognize the elastic modulus of various phases with high accuracy and distinction. AFM results show that the Young modulus of quartz is 7.4 GPa and the Young modulus of minerals is 2.28 GPa. Moreover, the modulus value in nanoindentation is higher than that in AFM. The difference in modulus results of quartz by AFM and nanoindentation is due to the selection in probe in AFM. Overall, it shows that AFM is more suitable for achieving the goal of identifying the modulus of various phases in tight sandstones. The knowledge obtained from this paper is promising in the application of nanoindentation and AFM in tight sandstones. It will also benefit the study of micromechanical characteristics of various phases in tight sandstones.

INTRODUCTION

Acquiring the mechanical property is beneficial for several engineering aspects. Such as designing hydraulic fracturing schemes, enhancing oil recovery, and keeping wellhole stability(Li et al., 2019; Shen et al., 2022; Q. Wang et al., 2022). Rock consisting of several minerals is widely accepted as a homogenous and complex material. In the conventional mechanical tests, the obtained results represent the overall mechanical characterization of rock, which is regarded as the identical mechanical property of minerals (Brotóns et al., 2013). Uniaxial and triaxial pressure tests are typically applied to characterize the mechanical property of rock(Palchik, 2011; J. Wang et al., 2021). However, from the micro-scale, there are different pore structures and components of the minerals in the rock. The result is that the micromechanical characterizations between several minerals differ a lot(Liu et al., 2021; Wu et al., 2020). Therefore, acquiring the micromechanical property of phases in rocks by conventional mechanical testing is a big challenge because of the heterogeneity and complexity of mineralogical composition in rock systems(T. Wang et al., 2022). That is to say, by obtaining the micro-mechanical properties of phases of minerals in the rock, we can have an explicit knowledge of the mechanical property of rock.
A Data Augmentation Method of Variable Density Logging Image Based on GAN
Authors: Wang Z. , Song X. Z. , Li Z. , Zhang Y. L. , Yang X. Y. , Pan T. , Zhu Z. P.
Published: September 2023

In recent years, with the development of artificial intelligence technology, cementing quality evaluation models based on supervised learning algorithms have been gradually proposed and applied. These models automatically evaluate cementing quality by identifying variable density logging images. However, due to the uneven number of training samples (variable density logging images), the accuracy of automatic evaluation models is low, to solve this problem, this paper proposes a Wasserstein distance generation countermeasure network (VDL-WGAN) for variable density well logging images. In VDL-WGAN, the generator network uses reconstruction loss to improve the image generation ability of the model. To evaluate image quality, this paper calculates the PSNR and SSIM values of the generated images and trains the optimal model. After expanding the samples, the intelligent evaluation model of cementing quality is trained to improve the recognition accuracy. The VDL-WGAN proposed in this paper can improve the generation of high-quality virtual samples of logging variable density images, improve the accuracy of the intelligent evaluation model of cementing bond quality, and achieve the effect of data expansion.

INTRODUCTION

The quality of cementing is related to the output and life of oil and gas wells. If the quality of cementing is not good, it will not only bring difficulties to the subsequent drilling and testing, but also greatly affect the production life of oil wells (Ravi et al, 1996). Therefore, it is of great significance to accurately evaluate the quality of cementing. At this stage, the most common method is to use the variable density logging image for evaluation. The logging interpretation experts evaluate the cement bond quality by observing the light, dark and thickness of the strips in the variable density logging image. However, the manual interpretation method has gradually revealed its disadvantages, and the efficiency of manual evaluation of cementing quality is low (Fang et al, 2022). With the rapid development of depth learning, many researchers have proposed to use convolution neural network to recognize the image of VDL to improve the interpretation efficiency (Fang et al, 2022, Viggen et al, 2020, Voleti et al, 2020). However, these methods need a lot of data to support their training, and the number of logging variable density data images is limited.
Prediction of Ground Movements Under Dipping Seam Conditions
Authors: Romero Benitez J. D. , Maldonado E. , Agioutantis Z.
Published: September 2023

The prediction of ground movements due to underground coal mining and their impacts on the surface are important considerations that have been studied by numerous researchers around the world. The majority of these studies have focused on the development of different analytical and empirical models for the prediction and calculation of ground deformation indices for either flat or gently dipping seams under variable topography. However, a few studies are available with respect to the prediction of ground movements under dipping seam conditions. Dipping seam conditions have been encountered in some cases in the US, where the inclination (dip) may be in the range of 10 degrees or greater. Ground movements under such conditions are evaluated using methodologies which assume horizontal seams for their calculations. In order to accurately predict subsidence under these conditions it is necessary to develop an appropriate methodology that builds on the existing infrastructure. This paper presents a methodology that can be used to model subsidence under dipping seam conditions. The methodology has been validated with two case studies that are available in the literature.

INTRODUCTION

Although new alternative energy sources are being developed, non-renewable carbon-based resources still constitute the base energy supply for many countries in the world. Coal production, 69% of which corresponds to electricity and heat generation (Çelik, & Özçelik, 2023), still plays an essential role in meeting the worldwide demand. The reduction of open-pit coal reserves has raised the need for underground coal mining, and, consequently, the need to enhance underground mining methods and technologies.

Although horizontal or near-horizontal coal seams constitute the majority of coal deposits currently extracted using underground mining methods, inclined seams are also being mined and will be mined even more in the future. Some countries, such as China, India, and Spain, classify high-quality reserves of coal as inclined strata (Afsari,1998).
Numerical Simulation and Operational Parameter Optimization for Staged Multi-Cluster Fracturing Horizontal Wells in Coal Seam Roof
Authors: Shi Hongwei , Zhao Haifeng , Li Xuejiao , Yao Wenji
Published: September 2023

The staged multi-cluster hydraulic fracturing technique of horizontal well in roof strata of coal seam is a new method for effective developing the broken-soft coal seam. Therefore, based on cohesive model and Bernoulli equation, considering the friction of fracturing fluid flowing through wellbore, perforation and the stress interference during fracture propagation, a finite element numerical model of multi-cluster fracturing of coal seam roof coupling wellbore and formation is established. The effects of perforation diameter, perforation number and injection rate on fracture extension were studied. The results indicated the fracture tip is always located in the roof during fracture dynamic propagation, and coal seam fractures are wider than roof fractures. During multi-cluster perforation in the fracturing section, the fractures initiated from each perforation cluster have competitive propagation. The stress interference between the fractures and the friction of the fracturing fluid make the distribution of the fracturing fluid between the perforation clusters uneven. Increasing injection rate, reducing number of single perforation cluster, and decreasing diameter of perforations hole can facilitate the even propagation of fractures in each cluster, and increasing the stimulated reservoir volume. The influence of the perforation diameter is significantly greater than the injection rate and perforations number.

INTRODUCTION

China has a wide distribution of broken soft coal seams that have low permeability, and hydraulic fracturing is the key to its efficient development. However, due to their low strength(S), low elastic modulus(E), and high Poisson's Ratio(ν), broken-soft coal seams have high plasticity compared to hard coals or other rocks (Li et al., 2021; Lyu et al., 2020). Long fractures are difficult to form in coal seams and the fracturing sand is severely inlaid when conduct hydraulic fracturing in the plastic broken soft coal seam directly. The stimulation effect is generally poor. In response to this problem, scholars have proposed indirect fracturing technology for coal seam roof. (Li et al., 2014; Olsen et al., 2007; Olsen et al., 2003; Zhang et al., 2018). The technology realizes the efficient extraction of coalbed methane in broken soft coal seam by arranging horizontal wells in the roof strata adjacent to the coal seam, and the fracture extends from the coal seam roof to the coal seam. The field test indicates that the application of this approach to broken soft low-permeability coal seam can significantly improve the efficiency of coalbed methane exploitation (Zhang and Bian, 2015).