bluuebunny/crossref_metadata_2025 huggingface dataset:
Pendampingan Warga Binaan Rehabilitasi Narkoba Kota Banjar dalam Pemanfaatan Tanaman Lokal
Authors: Rohimah Siti , Hertini Reni , Suhariyanti Enik , NIralam Deni , Permana Indra , Zulfikar Zulfikar
Published: August 2024

This community service program aims to assist drug rehabilitation inmates in utilizing local plants such as Hangasa (Amomum dealbatum), Parahulu (Vatica scortechinii), and Honje (Toona sinensis) for health and environmental conservation. This program was conducted with a participatory approach for 1 week, involving 50 participants who received theoretical and practical training. Quantitative results showed a significant increase in participants' knowledge and skills, with an average increase of more than 28% in all aspects assessed. Qualitative results showed an increase in participants' awareness of the importance of environmental conservation and positive social impacts in the form of working group formation and community empowerment planning. In conclusion, this program was successful in increasing knowledge and skills in supporting environmental conservation. Recommendations for future implementation include developing sustainable support and increasing public education. This holistic approach has the potential to be applied in other locations to support community rehabilitation and development.
Pelatihan Kader Dalam Penanganan Hipertensi: Optimalisasi Terapi Daun Sirsak Sebagai Bentuk Konservasi Yang Berbasis Kearifan Lokal
Authors: Rosdiana Nina , Suleman Happy Kurniati , Rosita Sinta , Asiah Selina Nur
Published: August 2024

Background As age increases, the body undergoes many changes, both in terms of physical and psychological. Striking changes are physical changes which often cause health problems are changes in the cardiovascular system. One of them is hypertension which often occurs in the elderly. Based on data from the Ciamis Regency Health Office, there are around 640 elderly people experiencing hypertension in Cipaku sub-district. Hypertension is a lifelong disease, so it needs to be treated and maintained so that blood pressure is always in a normal state. One of them is by using alternative therapy of soursop leaf decoction water which in the Ciamis area itself has many soursop trees. The object of this service is health cadres in the Ciamis district area as many as 30 cadres. The method of this service is to provide training to cadres about soursop leaf decoction water and its impact on blood pressure. The results showed that the cadres' knowledge became better after being given this training with a picture of knowledge with an increase of 26.0. Conclusions Soursop leaf decoction water can be used as an alternative therapy in maintaining normal blood pressure. therapy in maintaining normal blood pressure.
Morphometric Characters and Meristic Counts of Mastacembelus armatus (Lacebede, 1800) from Maruthur Anicut, Tirunelveli District, India
Authors: P Raja , S Muthukrishnan , Reneese Joseph Antony
Published: August 2024

The present study highlights about morphometric measurement and meristic count of Mastacembelus armatus (Lacebede, 1800) collected from the Maruthur wetland ecosystem have been investigated with 23 specimens to observe the relationship between morphometric characters. Identification of species is an initial step in any research work and plays a vital role in the behavioural study. Morphometric character analysis and meristic counts are considered as simplest and authentic methods for fish species identification which is termed as morphological systematics. Fourteen different morphometric characters in percentage of total fish length (9 characters), head length (5 characters), and five different meristic counts (branched and unbranched rays) have been studied. The obtained result reveals that morphometric characters vary depending on the growth and size of the fish. However, the meristic counts were comparatively similar. All the characters show a positive correlation both in the percentage of total length and head length. The different morphometric and meristic counts of M. armatus have been analyzed for the population dynamics which includes taxonomy study and proper identification of fishes. The fin formula was calculated for some hard rays and soft rays. Therefore, this study supplement additional data for the identification of the fish species.
STUDI KORELASI DUKUNGAN KELUARGA DENGAN KEAKTIFAN LANJUT USIA DALAM PELAKSANAAN POSYANDU LANJUT USIA
Authors: Pratiwi Putri Martalia Henni , Siswantoro Edy
Published: August 2024

Posyandu lanjut usia (lansia) merupakan salah satu upaya meningkatkan derajat kesehatan dan mutu pelayanan kesehatan lansia di masyarakat, bahagia dan berdaya guna bagi keluarga serta komunikasi antara masyarakat lanjut usia. Fenomena di RW 08 Kelurahan Sidotopo Wetan Kecamatan Kenjeran Kota Surabaya, beberapa lansia tidak rutin mengikuti kegiatan posyandu lansia yang diadakan di balai RW. Tujuan penelitian ini adalah untuk mengetahui hubungan dukungan keluarga dengan keaktifan lansia dalam pelaksanaan posyandu lansia di RW 08 Kelurahan Sidotopo Wetan Kecamatan Kenjeran Kota Surabaya. Desain penelitian ini menggunakan metode cross sectional. Dengan Teknik sampling Simple Random sampling. Sampel yang diambil sebanyak 33 responden yaitu lansia yang tinggal bersama keluarga yang berusia > 60 tahun. Setelah itu data dikumpulkan dengan kuesioner kemudian dianalisis dengan uji Spearman Rho dengan tingkat kemaknaan α = 0,05. Hasil penelitian didapatkan seluruhnya (100%) yaitu 17 responden memiliki dukungan kurang dan tidak aktif mengikuti kegiatan posyandu lansia, sebagian kecil (40%) dukungan lansia cukup dan lansia aktif mengikuti kegiatan posyandu lansia. Hasil uji Spearman Rho dan diperoleh nilai signifikan ρ = 0,000 dan α = 0,05 atau (α<0,05) yang berarti H1 diterima artinya ada hubungan antara dukungan keluarga dengan keaktifan lansia mengikuti posyandu lansia di RW 08 Kelurahan Sidotopo Wetan Kecamatan Kenjeran Kota Surabaya. Dukungan keluarga yang baik akan membantu meningkatkan keaktifan lansia dalam mengikuti posyandu lansia. keluarga lansia dapat memberikan dukungan yang lebih baik lagi kepada lansia terutama dalam kondisi kesehatan dengan mendukung lansia supaya aktif mengikuti posyandu lansia dengan cara mengingatkan jadwal dan mengantarkan lansia ke tempat posyandu agar dapat meningkatkan kekatifannya dalam mengikuti posyandu lansia
PENGARUH PENDIDIKAN KESEHATAN TENTANG SADARI DENGAN MEDIA DEMONSTRASI DAN VIDEO TERHADAP PERILAKU SADARI PADA REMAJA PUTRI
Authors: Rosyidah Nanik Nur , Supriani Anik
Published: August 2024

Kanker payudara (carcinoma mammae) merupakan tumor ganas yang tumbuh di dalam jaringan payudara. Gejala permulaan kanker payudara sering tidak disadari atau dirasakan dengan jelas oleh penderita, sehingga banyak penderita yang berobat dalam stadium lanjut. Kanker sebenarnya dapat dideteksi pada tahap awal, termasuk kanker payudara yang dapat dilakukan dengan pemeriksaan payudara sendiri (SADARI). Dengan demikian, pengobatan dini diharapkan dapat memperpanjang harapan hidup pasien. Banyaknya remaja yang tidak paham tentang bagaimana cara meraba yang tepat pada payudara serta ketidaksiapan mental dan takut apabila ditemukan adanya perubahan ciri-ciri abnornal (benjolan) atau kanker didalam tubuhnya menjadi salah satu faktor penyebab wanita tidak melakukan pemeriksaan payudara sendiri atau SADARI. Desain penelitian yang digunakan dalam penelitian ini adalah Quasy Eksperiment dengan bentuk Nonequivalent Control Group Design. Teknik sampling dengan cara total sampling. Populasi sebanyak 30 responden. Sampel diambil seluruhnya yaitu 30 responden. Instrumen yang digunakan adalah lembar kuesioner. Setelah data terkumpul dianalisis dengan Uji Man Whitney. Hasil uji statistik menggunakan Uji Man Whitney Test didapatkan nilai sig. 8.66 dan nilai α > 0,05 artinya Ada Pengaruh Pendidikan Kesehatan Tentang SADARI Dengan Media Demonstrasi dan Video Terhadap Perilaku SADARI Pada Remaja Putri Di Desa Lengkong Kecamatan Mojoanyar Kabupaten Mojokerto. Dari penelitian ini diharapkan remaja harus senantiasa meningkatkan perilaku SADARI. SADARI merupakan salah satu upaya mendeteksi dini kanker payudara. SADARI harus dilakukan rutin satu bulan sekali setelah menstruasi. Jika SADARI dilakukan secara rutin maka akan meningkatkan perilaku SADARI yang awalnya berperilaku negatif menjadi berperilaku positif
Transformation in Journalism: Photojournalism in the Era of Augmented Reality
Authors: Naz, Mehmooda , Khan (PhD) Dr.Musa
Published: August 2024

Field of photojournalism is conveniently developed after the incredible advancement in visuals by the convergence of technology which have made communication more convenient. Convergence in photojournalism determine various expansions, deal with the creative line of augmented reality in relation to the future. The objectives of this paper include to identify possible effects related to the convergence of Augmented Reality as an emerging technology in visual media communication in the form of photojournalism. Augmented reality is digital collaboration between digital, visual, and verbal content to bring context on the ensuring level of clarity. The advancement of this tool played a vital role in various fields of communication, education, advertisement, and business. However, literature review defines a gap that photojournalism is somehow under-discussed area. This paper examines the converging advanced technology of augmented reality with photojournalism that has become more effective and increase a level of information in print media. The paper further investigates and explain the under-discussed area of photojournalism with the use of augmented reality in the future. Following the qualitative method approach, data were collected from the experts in the field through in-depth interviews. Data were analyzed through thematic analyzes. The findings show that experts in augmented reality and photojournalism are agree to accept the futuristic reliable quality of AR in photojournalism and also drive a focus of attention towards some precautions regarding technology.
Natural Law, Constitutionalism and Media Laws: What’s Amiss in Media Regulations?
Authors: Quddus Usman , Ahmed Dr.Ghufran , Ashraf Zeeshan
Published: August 2024

The adverse effects of media today mandate the mulling of appropriate reforms for effective regulation of media. The research in hand attempts to study the adverse impacts of biased reporting and subsequently suggests suitable reforms for improving media legislation. The methodology is descriptive, comparative, and critical. Findings propose minimum content of media laws for all jurisdictions based on naturalism and constitutionalism. Naturalism and constitutionalism are the ends of the law and provide protection of life, liberty, property, dignity, etc. Naturalism means natural law i.e. ultimate values to which all laws must conform. Constitutionalism in this research connotes the ultimate law in a country based on natural law e.g. U.S. Constitution which is based on natural law. Results have significance across the world for improving the standards of media reporting. Studies of this kind proposing media reforms have been attempted before without any meaningful results proposed. U.S., India, and the Islamic Republic of Pakistan have been chosen for case studies of media laws due to the rise of increasing intolerance in these countries.
GENDER DISCRIMINATION IN PAKISTANI MEDIA INDUSTRY: A JOURNALISTIC PERCEPTION
Authors: Ali Abid Naqvi Syed , Munir Dr. Asad , Ansar, Sharoon
Published: August 2024

Females are countering different problems is every walk of life and journalism is no exception. This study “Gender Discrimination in Media Industry: A Journalistic Perception from Pakistan” aims at examining the perception of Pakistani journalists regarding the issues faced by female journalists with three research question, Firstly, what gender issues exist among women journalists in Pakistan? Secondly, what challenges do women journalists face in Pakistan? And thirdly what should be the possible solution and polices for gender discrimination in Pakistan media industry?The study involves a quantitative approach and Survey design was adopted. Questionnaire was the main instrument with closed ended questions and the responses were measured on 5 point likert scale. All the registered members of National Press Club Islamabad were taken as the population and 347 respondents were taken as sample frame. Census approach was used for distribution of electronic questionnaire.
This study reveals that majority of male respondents strongly agreed that female journalists face gender discrimination in media industry. Most of the male respondents strongly agreed with that there are some possible solution and polices should be present for gender discrimination in Pakistan media industry like, improvement in recruitment system, equal opportunities for development, recognition of genuine work.
Etika Profesi Pariwisata Yang Perlu Dimiliki Oleh SDM Pada Masa Revolusi 4.0: Teknologi Yang Mereduksi Manusia Sebagai Tenaga Kerja
Authors: Indra Febryola , Suryadi Evelyn , Gosal Manopo Gloria Blessing , Lee Michelle
Published: August 2024

Artikel ini mengkaji mengenai perkembangan teknologi yang telah berkembang pesat hingga mengalami transformasi besar dimana sumber daya manusia mulai tergantikan oleh adanya robot atau komputer yang memiliki kecerdasan mirip dengan manusia. Tantangan yang muncul bisa berupa kecemasan karena teknologi yang dapat mereduksi atau mengurangi manusia sebagai tenaga kerja, khususnya tenaga kerja dalam bidang pariwisata. Jika kualitas sumber daya manusia lemah maka tidak dapat dihindari manusia bisa tergantikan oleh teknologi. Artikel ini bertujuan untuk menganalisis dan menemukan solusi untuk mengurangi rasa kecemasan tersebut, yaitu perlu adanya sumber daya manusia yang berkompeten (hard skill) dan beretika (soft skill) sehingga kehadiran revolusi 4.0 dapat disikapi dengan bijaksana karena pengaruhnya dapat menjadi peluang atau bahkan menjadi tantangan bagi manusia yang menciptakan teknologi itu sendiri. Adapun metode penelitian yang digunakan adalah metode kualitatif yang dilakukan dengan menggunakan studi kepustakaan literatur yaitu teknik penelitian yang bersumber dari jurnal ilmiah, buku ataupun karya ilmiah yang lebih menekankan deskriptif.
Geomechanical Analysis of Caprock Integrity and Fault Stability for Greensand CO2 Storage Project Feasibility
Authors: Younessi A. , Kårstad E. , Basu P. , Larsen M. , Burachok O.
Published: August 2024

A comprehensive geomechanical assessment is carried out to investigate the upper pressure limit of CO2 injection for the depleted Frigg Sand oil reservoir in the Nini field, offshore Denmark. The mechanical stability of the Frigg Sand reservoir, shale caprock and key intersecting faults was investigated using a field-scale coupled finite element model built for the target storage reservoir, taking into account the forecasted CO2 injection plan. The analysis shows that the calculated threshold pressure to initiate tensile failure in the caprock is considerably above the planned CO2 injection pressure. The results also show that there is no risk of shear failure in the caprock for the entire studied area. The fault stability analysis shows that no risk of fault reactivation exists in the overburden. However, some faults may reach the critical stress state for reactivation in the reservoir with high injection pressures. Overall, the most likely mode of failure is possible tensile failure in the caprock and this defines the safe operational limit for the Frigg Sand reservoir. Thorough analyses using a field-scale finite element simulation coupled with the reservoir flow dynamic simulations helped to capture the risk associated with the CO2 injection operation and to optimize the injection plan.

1. INTRODUCTION

Project Greensand is a geological CO2 storage project located in offshore Denmark. The storage layer is the depleted Frigg Sand reservoir approximately 1800 m below the seabed in the Nini field. The Frigg Sand reservoir has a potential storage of 0.5 million tonnes of CO2 per year by 2026 with an expected storage capacity of 5.0 million tonnes. Modeling and monitoring the subsurface behavior throughout the CO2 injection is key to a permanent, efficient and secure storage. Subsequently, as part of the injection design, a comprehensive geomechanical analysis was carried out to investigate the impact of the CO2 pressure on the caprock and fault stabilities near the injection zone and estimate the upper pressure limit of the CO2 injection.
Poroelastic Properties of Indiana Limestone
Authors: Kalbekov A. , Naumann M. , Duranti L. , Prasad M.
Published: August 2024

This research investigates the poroelasticity of Indiana Limestone, focusing on how confining and pore pressures affect properties like porosity, permeability, and wave velocities. We analyzed the dynamic and static stiffnesses, highlighting the influence of hydraulic properties on rock elasticity. Findings indicate that, for this set of rocks, higher permeability possess greater stiffness and faster velocities, due to improved grain cementation and lower surface areas per grain volume. Additionally, we discovered a linear relationship between dynamic and static effective stress coefficients. A significant outcome is the stress dependency on Biot's coefficient, with considerable changes observed after a 20 MPa differential pressure change, underscoring the necessity for pressure-adjusted estimations rather than utilizing a constant value for a rock as per industry standards. Moreover, our experiments show that deionized water interaction softens the carbonate's matrix, challenging traditional fluid substitution models like Gassmann's in predicting rock stiffness accurately.

1. INTRODUCTION

Classical elasticity theory does not completely explain the behaviors of petroleum and CO2 reservoirs due to the presence of pore fluids and changing boundary conditions that affect the mechanics of porous rocks (Detournay & Cheng, 1993).

A porous medium saturated with fluid is composed of a solid matrix and interstitial fluid, which coexist and interact in the following ways: (1) an increase in pore pressure when external force is applied, and the fluid is trapped within the system; and vice-versa, (2) dilation of the system in response to applied internal pore pressure (Detournay & Cheng, 1993).

In the realm of infinitesimal deformations, solids are regarded as elastic entities (Gassmann, 1951a; 2007). The dynamics of an isotropic porous material subjected to diverse stresses are encapsulated by strains, as elucidated by Nur and Byerlee (1971):

(equation)

In this context, σij represents Kroenecker's delta, and the notation of repeated indices implies a summation, with

σkk representing the hydrostatic stress. The right-hand side of the equation is divided into three distinct parts: the first part reflects the rock's response to deviatoric stresses, which is strictly controlled by the shear modulus G. The middle part describes the deformation resulting from hydrostatic compression, characterized by the bulk modulus K. The third part illustrates the dilation of the porous rock due to variations in pore pressure, with 1/Kbp representing the poroelastic expansion coefficient, also known as the pseudo-bulk modulus (Biot, 1941). This approach uses a sign convention in which compression is considered positive.
Use of Minifrac and PVC Data to Constrain Re-Pressurization Stress Path
Authors: Zhang J. , Edwards S. , Majidi R. , Mahadev K. , Duvivier G.
Published: August 2024

Determination of minimum horizontal stress (Sh) and its alteration with reservoir pressure (or stress path) is critical for efficient drilling, completion, production, intervention, and reservoir management. A comprehensive method is developed to constrain stress path for both depletion and re-pressurization by integrating the actual field mini-frac and rock mechanics laboratory pore volume compressibility (PVC) test data.

PVC test demonstrates that the stress path decreases with depletion. Field data from three reservoirs in Gamma Field and one reservoir in Delta Field in deep-water wells in the Gulf of Mexico (GoM) show that stress path measured from PVC test agrees very well with the stress path defined from minifrac tests. Therefore, it can be used to predict Sh for depleted sand. The calculated stress path for re-pressurization shows that the higher the stress path for depletion, the higher it is for re-pressurization. The most likely stress path is 0.66 for depletion and 0.56 for re-pressurization for Reservoir B and 0.70 for depletion and 0.61 for re-pressurization for Reservoir C.

The results from this study have been used to determine the depleted sand fracture gradient for drilling and operation pressure limit for well intervention.

INTRODUCTION

It is critical throughout the various phases of drilling, completion, production and intervention to understand and predict the evolution of reservoir pressure and in-situ stresses especially when production is ongoing, and the reservoir becomes progressively depleted. Stress path is introduced to evaluate how the in-situ stresses change with reservoir pressure variation. There are three stress path parameters that relate to the three principal stresses, overburden (Sv), maximum horizontal stress (SH) and minimum horizontal stresses (Sh) to reservoir pressure alteration (Sayer, 2006, Zhang et al. 2021a & 2021b). Stress path for Sh is discussed in this paper.

Stress path can be measured in the lab by running pore volume compressibility (PVC) tests. Through various methods of loading and unloading, there are three types of PVC tests that can be conducted: "true" depletion, effective stress, and rate type compaction method (RTCM). Zhang et al. (2021a) found that the Sh calculated by using the stress path measured from PVC tests matched very well with the minifrac and drilling losses data from two fields in deep water Gulf of Mexico. It is also discovered that "true" depletion method is more accurate when compared to effective stress and RTCM methods. This observation seems to agree with the physics of the test.
Study on the Mechanism of Wellbore Stability and Drilling Fluid Technology Countermeasures in Ultra-Deep Composite Salt Formations in the Tarim Basin
Authors: Zhang Zhen , Fang Zheng , Li Jiaxin , Sheng Yong , Zhou Bo , Zhao Li , Lu Yunhu
Published: August 2024

In the Tarim Oilfield, drilling encountered the Cambrian strata's composite salt layer, resulting in significant wellbore narrowing and collapse. The lithology of the composite salt layer primarily consists of salt and gypsum interbed, exhibiting complex and variable features. Given the recurring drilling incidents, it is imperative to investigate wellbore instability mechanisms within these composite salt layers and adjust related drilling fluid techniques. This paper analyzed the engineering properties of composite salt rock, carried out experiments on physical and chemical properties and rock mechanical strength, and elucidated the control mechanism of wellbore stability of composite salt rock; experiments were carried out on the dissolution rate and creep characteristics of salt rock, and a model for characterizing the density and chlorine content of drilling fluids for maintaining the wellbore stability was set up. Model analyses and on-site verifications were carried out. The study results show that the composite salt layer belongs to the wellbore stability mechanism controlled by the combination of dissolution and creep in water; the appropriate drilling fluid density and chloride ion concentration can prevent the dissolution and creep of the composite salt layer. By utilizing the appropriate density of undersaturated brine drilling fluid and fine-tuning the chloride ion concentration, the salt rock's dissolution rate and creep rate in the wellbore can be effectively balanced, and the wellbore stability can be improved.

1. INTRODUCTION

Wellbore instability poses a significant global technical challenge in drilling engineering [1]. Salt and gypsum layers are common in both onshore and offshore deepwater oil and gas drilling [2-3]. During drilling operations, especially in the case of composite salt layers, the variable lithology and complex mechanical, physical, and chemical properties exacerbate the issue of wellbore instability, leading to incidents such as narrowing, enlargement, collapse, and sticking [4-5]. Consequently, both domestic and international scholars have conducted extensive research on collapse prevention drilling fluids for salt and gypsum layers, leading to the development of relatively mature saturated and undersaturated brine drilling fluid systems [6]. These advancements have contributed to alleviating the complexities encountered in downhole operations. However, due to limitations in research approaches and the focus on specific regions, as well as the inherent complexity and variability in lithology and structure of salt and gypsum layers across different areas [7], the issue of wellbore instability in composite salt layers remains unresolved.
Preliminary Blast Fragmentation Modeling in an Underground Aggregate Operation
Authors: Shields L. , Calnan J. , Silva J. , Maldonado E. , Agioutantis Z.
Published: August 2024

The availability of fragmentation models for underground mine-to-mill optimization is fundamental, given that fragmentation models establish which blasting parameters can be manipulated to produce a desired particle size distribution. Given the ever-changing conditions in which mining takes place (geology, stress conditions, mining procedures, etc.), any applicable model must be flexible, adaptable, and dynamic to provide a range of predictions with acceptable accuracy. This paper discusses the results and model validation of using multivariate regression analysis to analyze blast fragmentation data from an underground aggregate operation. These are the initial results with respect to the development of a probabilistic model for underground bench blasts that predicts the resultant particle size distribution.

1. INTRODUCTION

In underground mining, optimizing blasting practices to achieve the desired particle size distribution (PSD) is crucial for enhancing downstream processing efficiency, energy consumption reduction, and overall ore recovery (Fuerstenau & Han, 2003). Traditional approaches to blast design and fragmentation modeling in surface mining operations have been well-established (Cunnigham, 1987; Kuznetsov, 1973, Lilly, 1986; Ouchterlony, 2003). However, the unique challenges posed by underground environments, including confinement conditions, excavation stability, and limited visibility, demand innovative solutions (Siddiqui et al., 2009; Demenagas, 2008).

The efficiency of aggregate quarry operations heavily relies on optimizing blasting processes, which directly impact subsequent stages of the mine-to-mill workflow. One critical aspect of this optimization lies in predicting the particle size distribution resulting from blasting activities (McKee, 2013). A thorough understanding of particle size distribution facilitates better control over downstream processes such as crushing, grinding, and sorting, ultimately enhancing overall operational efficiency and profitability.

Traditionally, the prediction of particle size distribution following blasting has been approached using empirical models or simplistic statistical techniques. However, the inherent complexity and variability of geological formations, coupled with the diverse characteristics of explosive materials, demand a more sophisticated and data-driven approach (Nadolski et al., 2015). In this context, Multivariate Regression Analysis (MRA) or Multivariate Multiple Regression emerges as a powerful tool for accurately predicting particle size distribution by incorporating multiple variables that influence blasting outcomes.
Proactive Identification of Adverse Geological Structure in a Deep Mine Environment
Authors: Hall A. , Marshfield S. , Simser B. , Howell L. , Lindsay J. , Cai M.
Published: August 2024

This paper details proactive measures taken to identify adverse geological structures present in the rock mass before mining occurred in the area. During the sinking of Glencore's Onaping Depth winze and subsequent excavation of the shaft stations, a major fault had to be crossed. This structure exhibited erratic behavior ranging from local wedge formation in tunnels to major rock bursting when it had been encountered historically at shallower depths. Through the use of scout holes, diamond drill holes drilled ahead of the mining face, the ground conditions around the fault ahead of the shaft and drift development were characterized. The holes provided a wealth of data for ground condition assessment, from physical examination of the core to in-situ evaluation of the rock mass using acoustic and optical televiewer surveys. Examination of the scout holes identified up to a 50 m zone of anomalous ground conditions below the fault. Based on the proactive identification of the anomalous zone, the ground support was enhanced, and the strategy for mining through the area was modified. Whenever feasible, permanent excavations were relocated further away from the fault zone. For the drives that had to go through the fault, conservative ground control measures were employed. This resulted in a significant risk reduction and improved operator safety associated with the construction of the critical excavations. Seismic data were collected while mining through this area, and the data confirmed the presence of anomalous ground conditions.

1. INTRODUCTION

The presence of large geological structures can be a significant factor leading to increased frequency of rockbursts and large seismic events in deep underground mines. Predicting the rock mass behavior associated with geological structures is challenging because the structures are not always easily identified until after an excavation has been made. Many geological structures are benign and cause few ground control problems. On rare occasions, a structure may have locked-in stress, which could potentially cause severe rock mass failures. Seismic monitoring is extensively used to provide real-time feedback on the local rock mass response to mining. To some extent, the data can be used to evaluate geotechnical risks. However, it is important to note that this dataset shows a response to mining activity and is not available until the excavation process begins. Reactionary mitigation efforts are employed after a rockburst or a significant seismic event has occurred, in contrast to proactive efforts aimed at preventing the event or reducing its potential damage severity.
Production Enhancement by Microproppants: Concept Proof Using Laboratory Experiment and Numerical Modeling
Authors: Han Yanhui , Liang Feng , Liu Hui-Hai
Published: August 2024

In our previous work, an improved fracturing treatment, which combines a mixture of solid delayed acid generating material (SDAGM) with microproppants in the pad/pre-pad fluids during the engineering process, was demonstrated to be an effective technology by a series of laboratory tests and further investigated with mesoscopic fluid dynamics – microscopic solid mechanics coupling simulations. In this work, two field-scale porous media fluid flow models, consisting of rock matrix, randomly distributed microfractures and a major hydraulic fracture, are developed to evaluate the production enhancement of using microproppants for a producing well in an unconventional reservoir. The rock matrix is constructed as porous media with hydraulic properties of tight carbonate formation. The fluid flow in the rock matrix and fractures are mutually communicated. The permeability of zones representing hydraulic fracture and microfractures are determined by upscaling the hydraulic conductivities of fracture and microfractures containing supporting proppants and microproppants. The simulation can predict the well productivity with and without microproppants in the hydraulic fracturing treatment. This developed model can be applied to optimize the concentration of microproppants in the field operation to maximize the well productivity.

1. INTRODUCTION

Horizontal drilling and multistage hydraulic fracturing are two critical technologies that make it economically feasible to produce hydrocarbon from unconventional reservoir formations. Horizontal drilling increases the wellbore length exposed to reservoir mass. Hydraulic fracturing enhances production by creating fractures and sustaining their opening using solid particles (called proppants) such that the contact area between producing rock mass and fluid pathways (fractures and well) are significantly increased.

Most unconventional formations, such as shales and tight carbonates, contain extensive natural microfractures. Before hydraulic fracturing treatment, these microfractures may be sealed and thus inactive. Hydraulic fracturing will change the stress state around the newly created main fractures, which may reactivate existing natural fractures impacted by the stress change (see Fig. 1). In addition, new microfractures may also be created. Similar to main hydraulic fractures, these microscopic fractures, pre-existing or newly created, will close after the hydraulic fracturing pressure is released. If they can be kept open (e.g., during production), the well productivity can be further enhanced significantly. However, the proppants designed for supporting the main hydraulic fractures cannot enter these microfractures because of their large size relative to the microfracture aperture.
Experimental and Numerical Investigations into Fracturing Process of Brittle Rocks
Authors: Khadivi Babak , Masoumi Hossein
Published: August 2024

Tensile strength plays a vital role in the efficient design of underground openings and support system in rock engineering practice. Among various approaches developed for estimating this property, Brazilian testing has received considerable attention in analytical, numerical, and experimental studies. The test has been deployed for various materials such as rock and concrete; however, its fracturing process at micro and macro scales has not yet been thoroughly characterized. In this study, a coupled experimental-numerical technique was used to characterize the failure process of granite to better understand the fracturing process of brittle rocks under indirect tensile loading. In the experimental part, two independent monitoring techniques, Acoustic Emission (AE) and high-speed imaging, were deployed to investigate micro and macro cracking processes. The sample's behaviour was then simulated using a Distinct Element Method (DEM) code through Trigon logic to further compare the brittle failure characteristics with the experimental results. The collective results revealed that the tensile microcracks are the first to initiate during the failure with higher intensity compared to shear microcracks, resulting in a dominant tensile failure at macro scale. Also, it was noted that the sample's failure started from the center, which keeps the Brazilian results valid for brittle rocks while some overestimations may be added due to following shearing and the lack of enough stiffness in the testing machine.

1. INTRODUCTION

The initiation of fractures in brittle rocks can occur through tensile events, highlighting the significant role of tensile strength in the design of rock engineering projects (Griffith, 1921, Tapponnier and Brace, 1976, Stacey, 1981, Diederichs and Kaiser, 1999, Perras and Diederichs, 2014, Khadivi et al., 2023). Therefore, accurate assessment of tensile strength and cracking mechanism is essential for better understanding the mechanical behavior of brittle rocks. The convenience of sample preparation and straightforward testing operation have made the Brazilian test the most popular approach to estimate the tensile strength across a wide range of materials (Hobbs, 1964, Barla and Innaurato, 1973, Jonsén et al., 2007, Bahaaddini et al., 2019). Valid testing results are obtained by inducing a tensile fracture at the center, splitting the sample along the compressive diameter into two halves (Colback, 1966, Carmona and Aguado, 2012).
Enhanced Method for Measuring Joint Roughness Using Sub-Millimeter Resolution 3D Laser Scanning
Authors: Shintassova M. , Sepúlveda S. A. , Fatolahzadeh S.
Published: August 2024

Accurate estimation of joint roughness is critical for characterizing the mechanical and hydraulic properties of rock joints, thereby contributing to informed assessments of the rock mass classification, shear strength, and permeability estimates. The most prevalent way to quantify joint roughness is the Joint Roughness Coefficient (JRC). However, this conventional approach has shown subjectivity and bias, which can significantly affect engineering design strategies. To accurately assess JRC, this study proposes to use 3D laser scanning technology. In this work, a high-resolution scanner was used in the field for the first time on borehole cores. Scanned 3D roughness surfaces were used to obtain statistical roughness parameters, followed by the determination of JRC using empirical equations. This paper examines the use of a sub-millimeter resolution scanner on the example of joint surfaces of core samples and discusses the importance of scanning resolution and noise reduction in the measurement of roughness of discontinuities. It was found that this approach is also applicable to several-meter-long joints in outcrop formations, provided that a scaling relationship for JRC is applied. The results indicated a similarity in JRC values derived from laser scanning and visual profiling tools.

1. INTRODUCTION

Joint roughness is a measure of surface irregularities of a rock fracture and is described by surface topography. This rock property is important to quantify the mechanical and hydraulic properties of rock joints. There is a range of contact and non-contact methods to measure it. Contact techniques include linear profiling and local surface orientation methods (Barton & Choubey, 1977; Fecker & Rengers, 1971). Non-contact tools are triangulation (structured light projection, photogrammetry) and distance measurement methods (laser scanning and laser profilometry) (Fardin, Feng, & Stephansson, 2004; Huang, Oelfke, & Speck, 1992; Jessell et al., 1995; Tatone & Grasselli, 2009).

The most common roughness parameter used in geotechnical practice is the Joint Roughness Coefficient (JRC) introduced by Barton and Choubey (1977). JRC is estimated based on a comparison of profiles of a joint surface obtained from a profile comb (Fig.1) to the standardized set of 10 roughness profiles of JRC values ranging from 0 to 20 (Fig.2).
A Comprehensive Comparison Between Discrete Fracture Network and Generalized Anisotropic Material Behavior for Modeling Jointed Rock Mass
Authors: Ko B. H. , Moallemi S. , Dang H. K. , Yacoub T.
Published: August 2024

Rock masses are blocky assemblages formed by networks of natural discontinuities (fractures), such as joints, foliations, shear zones or faults, formed by geological activities. To accurately predict the mechanical behavior of rock mass, it is essential to consider these fractures. The complex interaction between intact rock and those fractures coupled with man-made excavation imposes critical limitations to predict rock mass behavior solely via kinematic or analytical methods. In this context, numerical modeling approach fills the need for a powerful tool that can provide geotechnical engineers with sophisticated solutions to complex rock mechanics problems. This paper demonstrates different approaches to model joint sets in 3D Finite Element Method (FEM) to model discontinuities in jointed open pit mine. They include the explicit representation of discontinuities using Discrete Fracture Network (DFN) and incorporation of a special constitutive model that considers anisotropic material behavior to the solid elements that implicitly account for the presence of joint sets. The investigation presents findings from simulations involving models with single and multiple joint sets. Notably, the focus is given to validating the use of DFN and the benefits for slope stability assessment. The obtained results showed high levels of agreement between the two modeling approaches, underscoring the efficacy of DFN in replicating the complex behavior of geological structures. These insights contribute to the enhancement of the rock slope designs with significant implications for the safety and profitability of mining operations.

1. INTRODUCTION

In open pit mining, the primary objective is to maintain the structural integrity of the slope surface and prevent/mitigate any potential failures. Achieving a cost-effective yet stable design for open-pit mines requires a comprehensive grasp of lithology, rock mass characteristics, and structural geology. Thus, conducting a robust slope stability assessment for open pit excavations is of utmost importance to ensure the safety of mining operations.

The presence of geological structures (also termed as natural discontinuities) such as joints, foliations, and faults within rock mass introduces complexities in stress distribution and stability, which are unique to the geological history of different regions. Therefore, a thorough consideration of natural discontinuities is imperative in geomechanical analyses and design exercises to gain accurate prediction of rock mass behavior. They play a pivotal role in controlling the driving failure mechanism to slope instability. With respect to the distribution, surface condition, and orientations of discontinuities, the mechanical response of rock mass should vary extensively.
Research on the Cuttings Transport in Large-Sized Hole Based on CFD-DEM Method
Authors: Zhao Jun , Huang Wenjun , Gao Deli
Published: August 2024

During drilling large-sized hole, due to the low return velocity of the drilling fluid and weak cuttings transport effect, it is difficult to clean the borehole, resulting in serious backpressure even pipe sticking, high equivalent circulating density (ECD), low rate of penetration (ROP), etc., which will bring significant time costs and economic losses. In this paper, a CFD-DEM coupling model is built to accurately simulate the dynamic transport process of cuttings. For the liquid phase, the Euler method is used to describe its motion characteristics through the flow field. For the solid phase, the Lagrange method is used to solve the variation of physical quantities of cuttings over time. And the coupling of fluid and solid phase is achieved through mutual forces. The reliability of this CFD-DEM coupling model is validated through experiments. Based on a large number of numerical simulations and the nonlinear regression method, a data-driven mathematical model for predicting the cuttings bed height is developed, which is useful in hole-cleaning design and drilling parameters optimization. The Pearson correlation coefficient R2 is 0.893451, indicating high accuracy of this mathematical model.

1. INTRODUCTION

Hole cleaning is one of the major challenges during drilling large-sized hole section, especially in the horizontal sections. Under the effect of gravity, cuttings will accumulate at the bottom of the annulus and be transported upwards in the form of cuttings bed. However, if the cuttings bed is too high, the cuttings in the lower part of the cuttings bed will be stuck and unable to move, resulting in the stationary bed that is difficult to remove and poor hole cleaning. This may cause downhole complications and accidents, such as serious backpressure even pipe sticking, high ECD, low ROP, etc., which bring significant time costs and economic losses. Therefore, conducting research on cutting transport is of great significance for on-site operations.

In the past, many researchers have conducted a large number of studies on cuttings transport, including experiments, numerical simulation and theoretical modeling. Experimental studies on cuttings transport began in the 1940s (Zhu 2022), analyzing the influence laws of various parameters through measured results and observation of phenomena. Sorgun (2013) summarized an empirical formula for the height of cuttings bed under water and four non-Newtonian fluids. Kim et al. (2014) studied the transport characteristics of cuttings in inclined annulus with the inclination of 30-75°. Song et al. (2017) proposed a mathematical model for cuttings concentration in a Microhole-Horizontal-Well based on 136 sets of experiments. Through massive experiments, Huque et al. (2022) believed that fluid velocity and cuttings size were the two most key parameters for cuttings transport efficiency in an inclined well.
Numerical Simulation of Enhancing Coalbed Methane Recovery by RF Heating with Small Spacing Well Pattern
Authors: Liu Rui , Dong Xuelin , Gao Deli
Published: August 2024

In recent years, electromagnetic (EM) heating excitation technology has been widely concerned in the exploitation of Coalbed methane (CBM). However, the heating volume of a single antenna in a vertical well is limited and cannot meet the needs of large-scale development. From the perspective of multi-well and multi-antenna, this paper establishes a mathematical model of radio frequency (RF) heating coupled with EM field and temperature field of small-spacing well pattern, comprehensively analyzes the average temperature and heating efficiency of coal seam heated by RF, reveals the influence law of different well types on the temperature distribution of coal seam, and conducts sensitivity analysis on heating power, well spacing and well pattern layout according to the characteristics of well pattern. The results show that triangular well pattern heating has higher heating efficiency and heating rate. Increasing the RF heating power can improve the heating rate and heating range of the coal seam, but too high power will form high temperatures near the wellbore, resulting in downhole equipment or wellbore integrity failure. On the whole, the spacing of heating wells has little effect on the average temperature of coal seam. The larger the spacing of wells in 5 ∼ 9 m, the larger the heating range, but the worse the superposition effect of temperature. Finally, according to the different well pattern layout schemes in the same reservoir, the optimal scheme is well pattern 1.

1. INTRODUCTION

CBM is a kind of unconventional gas in coal seams. Deep coal seam has the characteristics of low formation pressure, low permeability and weak gas saturation, which are the biggest challenges faced by coalbed gas exploitation (Gao et al., 2022). To overcome these challenges, engineers and researchers have proposed a number of methods, such as hydraulic fracturing, blasting, partial pyrolysis, solvent extraction, inert gas displacement, etc. (Guo et al., 2020). These methods can be divided into two categories: decompression and anti-reflection mechanisms. However, these approaches face environmental and economic challenges. In recent years, thermal stimulation technology has been widely concerned as an alternative method to increase natural gas production in unconventional reservoirs.