bluuebunny/crossref_metadata_2025 huggingface dataset:
Otaria Exercise for the Influence of 8-hydroxydeoxyguanosine (8-ohdg) in Postpartum Women
Authors: Januarsih Januarsih , Mallongi Anwar , Kristiana Efi , Rafidah Rafidah , Yuliastuti Erni , Darmayanti Darmayanti
Published: November 2023

Objectives: If a woman is in a physiological post partum condition, there will be an increase in the production of free radicals in her body. This situation will be worse if the woman is undergoing pathological postpartum, the production of free radicals in her body will be even greater. This condition is known as "oxidative stress".   Theoretical Framework: Doing Otaria exercise will affect the muscle's need for oxygen, which will increase, meaning it requires strong blood flow like the uterine muscles. By doing postpartum exercises, it will stimulate uterine contractions, so that uterine contractions will be better, the release of lochia will be smooth, which will affect the uterine involution process.   Method: The design used in this research was Post Test Only Control Group Design or post test with experimental and control groups. The sample in this study was 20 respondents in the experimental group and 20 respondents in the control group.   Results and conclusion: In postpartum mothers, there is an increase in lipid peroxidation products, especially 8-OhdG. The 8-OHdG is one of the product compounds of the lipid peroxide reaction which is also used as a marker of oxidative stress   Implications of the research: Research implications: midwifery services, maternal and child health and the reduction of maternal and infant mortality rates are affected by this study. The potential for quality midwifery care in the postpartum period can benefit the health of mothers and their babies. This study allows for further research and collaboration in the future to further reduce maternal mortality in the post partum period.
Innovation E-Learning Affecting the Efficiency of Employee: A Case Study of Airports of Thailand Public Company Limited
Authors: Kiewkong Phrompatsorn , Saengnoree Amnuay , Deepijarn Samart , Vuthisopon Sujira
Published: November 2023

Introduction: Human resource development from Innovation E-Learning is one of the important steps in Human Resource Management that affects the efficiency and success of modern organizations that are prone to high technological changes starting from the moment those employees come to work by orientation and must continue training and development continuously throughout the time. The current administration cannot therefore use the traditional methods that were used in the past but must be ready to accept changes from various factors and adjust to keep up with the situation at all times. Therefore, “Electronics Learning Innovation” is therefore a necessity of organizational management in the current era (Covid-19) and in the future in order for the organization to continue to be successful and produce effective personnel.
 
Objective: This dissertation aims 1) to examine the components of online learning efficiency 2) to explore the variables influencing the online learning efficiency of Airports of Thailand (AOT) employees.
 
Method: This is quantitative research. The sample is employees of Airports of Thailand Public Company Limited for 340 people through quota and simple random methods. The research tool is questionnaire and data are analyzed by descriptive and inferential statistics, confirmatory component analysis and SEM.
 
Results: E-learning Innovation and Human Resource management have direct influence on job satisfaction. Moreover, Innovative Electronic Learning and Personal Learning have direct influence on Performance Efficiency through the intermediate variable of Performance Satisfaction. According to the results of SEM, overall Innovative Electronic Learning has the highest influence on Performance Efficiency, followed by Performance Satisfaction, Human Resource Management and Personal Learning, respectively.
 
Conclusion: This research is a guideline for AOT to develop personnel's operational potential through learning with e-learning innovation. This research adds the value to the concept of E-learning, Innovative Electronic Learning, Human Resource Management, Personal Learning for airport companies.
Reinforce Human Resource Performance Through the Implementation of E-Government and Leadership in the Government Organization
Authors: Umiyati Sri
Published: November 2023

Objective: This research aims to analyze the relationship between e-government variables and human resource performance and analyze the relationship between leadership and human resource performance in government organizations.

Method: This research method is quantitative research using surveys, research data was obtained by distributing online questionnaires via social media. The questionnaire was designed using a Likert scale of 1 to 7. The respondents for this research were 458 senior government office staff who were selected using a simple random sampling method. Research data was analyzed using structural equation modeling (SEM) partial least squares (PLS) with the SmartPLS 3.0 software tool. The research stages are the outer model test, namely the validity, reliability test and the inner model test, namely the significance test or hypothetical test. The hypothesis of this research is that there is a positive and significant influence between e-government on performance and there is a positive and significant influence between leadership and performance.

Results: Based on the results of analysis tests using structural equation modeling (SEM) partial least squares (PLS) with the SmartPLS 3.0 software tool, it was found that the relationship between e-government and performance resulted in a p value of less than 0.050 and a T value of greater than 1.96. The relationship between leadership and performance results in a p value of less than 0.050 and a T value of greater than 1.96.

Conclusion: The conclusion of this research is that there is a positive and significant influence between e-government on performance and there is a positive and significant influence between leadership and performance. E-government and leadership are important factors for improving the performance of human resources in government organizations.
The Role of The Actuary in Assessing Financial Risks: a Case Study of Iraqi Insurance Companies
Authors: Jarallah Seenaa Ahmed , Bougatef Khemaies
Published: November 2023

Objective: This study aims to examine the role of actuaries in assessing financial risks in insurance companies, their roles in applying financial risk assessment methods, and the authority granted to them for comprehensive risk assessment. Indeed, some companies may impede actuaries from performing their duties effectively by limiting their authority, causing obstacles and inability to perform their duties. Thus, the main objective of this paper is to assess to what extent actuaries could manage financial risk in insurance companies in spite of all the challenges and difficulties that they face.

 

Methods: The study objectives are achieved by using data collected from a questionnaire distributed to employees of Iraqi insurance companies. A total of 165 forms were distributed, and 150 of them were retrieved and validated for statistical analysis.

 

Results: The findings reveal a strong positive association between actuary’s dimensions and the dimensions of the financial risk assessment. This relationship reduces investment risks and enhances pricing and estimation processes.

 

Conclusion: The positive association between all the actuary’s dimensions and the dimensions of the financial risk assessment highlights the active and essential role of actuaries in assessing both internal and external risks.
QUADROS DE ANSIEDADE E ESTRESSE EM ENFERMEIROS DA ATENÇÃO PRIMÁRIA À SAÚDE
Authors: Brito Gessyka Nunes Rocha , Da Rocha Leiliane Tavares , Da Silva Manuelle Rodrigues
Published: November 2023

A atenção primária à saúde é aporta de entrada para os demais serviços ofertados pela rede pública de saúde, no Brasil. Assim, o enfermeiro exerce um papel importante na equipe, o que lhe confere muitas atribuições. Nesse contexto, o objetivo do estudo é analisar a literatura sobre os quadros de estresse e ansiedade vivenciados por enfermeiros que atuam na Estratégia Saúde da Família. O estudo se trata de uma revisão integrativa da literatura, a partir de artigos publicados entre os anos de 2018 e 2023 nas bases de dados Literatura Latino-Americana e do Caribe em Ciências da Saúde (LILACS), Base de Dados em Enfermagem (BEDENF), Medical Literature Analysis and Retrieval System Online (MEDLINE) e SCIENCE DIRECT. Foram incluídos 12 artigos, dos quais 7 (58,3%) foram obtidos na MEDLINE e 5 (41,7%) na SCIENCE DIRECT. Quanto ao ano de publicação, 6 (50%) são de 2022,4 (33,3%) de 2021 e 2 (16,7%) de 2023. A maioria (75%) são estudos transversais e abordam a pandemia de COVID-19, enquanto 2 (16,7%) são estudos qualitativos e 1 estudo de coorte. O estudo concluiu que a pandemia de COVID-19 foi responsável por desencadear os fatores que levaram a quadros de ansiedade e estresse em enfermeiros que atuam na atenção primária. São necessárias novas pesquisas que abordem o trabalho desenvolvido pelo enfermeiro, na atenção primária, destacando seu protagonismo e suas lutas diárias para promover a saúde.
Unveiling the Thematic Landscape of Cultural Studies Through Bibliometric Analysis
Authors: Gómez Cano Carlos Alberto , Sánchez Castillo Verenice
Published: November 2023

Introduction: the sociology of knowledge has been a source of interest for researchers. The implication of bibliometrics as a science for the construction of scientific knowledge in the different branches of knowledge, especially the social sciences, occupies an important center.Objective: characterize the research published in Scopus referring to cultural studies.Method: a bibliometric analysis was carried out on the articles referring to cultural studies published in the period 2018 – 2023 in journals subscribed to the Scopus database. The SciVal tool was used to collect the information. Bibliometric indicators were analyzed. Descriptive statistics were applied.Results: A total of 169 434 documents were found in the thematic category Cultural Studies, of which 37,9 % were open access, with a trend of increasing scientific production. In the period from 2018 to 2022, researchers worldwide have contributed 3 674 topics on Cultural Studies. A marked concentration of these topics was observed in the area of Social Sciences and Psychology, which is to be expected if one takes into account that these are prominent areas due to their relevance in the study of human interaction and social behavior. The most productive countries were the United States, United Kingdom, Russia, Spain and Australia. On the other hand, with respect to collaboration indicators, 70,5 % of the papers had no collaboration and only 6,9 % of the studies had international collaboration, which is to be expected given that cultural studies are mostly developed in a local or regional context.Conclusions: scientific production in matters of cultural studies showed gradual growth in correspondence with topics of interest to the scientific community. The focus of the studies was located on high-impact journals in correlation with the behavior of the citations received. At the same time, the collaboration was characterized by its institutional nature
The Effect of Nutrition Education on Knowledge, Attitudes, and Iron Intake in Adolescent Girls
Authors: Zakiah Sitti , Toaha Aminah , Abri Nur , Wahyutri Endah
Published: November 2023

Anemia in adolescent girls is still a health emergency in developing countries, including Indonesia. This is still a priority scale for health management in various countries because it will harm the generation to be born. The education movement is considered very effective and efficient in preventing problems early. This study aimed to determine the influence of education on the knowledge, attitudes, and iron intake of adolescent girls at Public high schools 1 Tanjung Redeb. The research method is an experimental Quasy with a design of two groups Pre-test and Post-test conducted in May-June 2023. 50 research samples were selected in total sampling. Nutritional status is measured using anthropometric tools, and knowledge, attitudes, and food recalls are obtained using questionnaires that have been validated by tests. Independent sample T-test and Paired T-test and Wilcoxson test. The results showed that there was an effect of nutrition education in the intervention group on increasing knowledge (p 0.000) while the control group did not (p 0.100), while attitude did not affect the intervention and control groups respectively (p 0.876) and (p 0.410). Nutrient intake in the intervention and control groups (p 0.709) and (0.143) respectively. There were differences in knowledge after education in the control and intervention groups (p 0.013). Meanwhile, attitudes and iron intake were no different (p 0.722) and (p 0.100) after intervention and control education.
Personalized Design of Student Autonomy in STEM Curriculum
Authors: Cheng Yu
Published: November 2023

This paper explores the implementation of personalized design approaches to enhance student autonomy in STEM (Science, Technology, Engineering, and Mathematics) education. The current state of STEM curriculum in China is examined, highlighting existing challenges in its implementation. The role of autonomy in learning is discussed, emphasizing its definition, importance, and its correlation with effective STEM learning. The paper then delves into personalized design approaches, including the customization of learning paths, integration of real-world applications, utilization of educational technology, and the adoption of project-based learning. Barriers to implementing personalized design are identified, encompassing teacher training, resource challenges, and cultural considerations. The advantages and implications of personalized design are discussed, focusing on improved student engagement, performance, and alignment with educational goals. The paper concludes by emphasizing the transformative potential of personalized design in STEM education.
THE EFFECT OF ENTREPRENEURSHIP EDUCATION, AND SOCIAL ENVIRONMENT ON ENTREPRENEURIAL INTEREST WITH SELF-EFFICACY AS A MEDIATING VARIABLE
Authors: Brahmatiyo Dodyk , Muwarni F. Danardana , Kusdiyanti Heny
Published: November 2023

Entrepreneurial interest is still quite low in Indonesia because it is known that until now the number of entrepreneurs has not been able to reach the ideal number, SMK as a vocational school must always develop its quality to realize high-quality graduates in answering the needs of the industrial world and creating new entrepreneurs. This study uses a quantitative approach with Partial Least Squares structural equation modeling (PLS-SEM) to predict and confirm the hypotheses given. This study uses Google Forms for data collection on students of the Tourism Business Department of SMKN 1 Trowulan in Mojokerto Regency. Respondents in this study were 184 student respondents. The results showed that the Social Environment could not explain Self-efficacy or Entrepreneurial Interest. However, the Entrepreneurship Education variable can explain Self-efficacy and Entrepreneurial Interest. Furthermore, Entrepreneurship Education will have more influence on Entrepreneurial Interest, if strengthened by Self Efficacy as a mediator variable. The Social Environment will not have a greater influence on the Interest in Entrepreneurship, although strengthened with Self-efficacy as a mediator variable
PENERAPAN TEKNIK REVERSE SURAL FLAP DALAM REKONSTRUKSI KULIT SETELAH PENGANGKATAN MELANOMA MALIGNA: SEBUAH TINJAUAN LITERATUR
Authors: Asril Fadly
Published: November 2023

Tumor melanoma merupakan penyakit yang cukup langka, namun bersifat mematikan. Untuk mengatasi permasalahan ini, sering kali perlu adanya operasi yang cukup besar, sehingga kemudian terdapat adanya cacat pada jaringan lunak yang sifatnya cukup penting. Penelitian ini kemudian bertujuan untuk melihat mengenai bagaimana Reverse Sural Flap dilaksanakan untuk dapat mengatasi pengelolaan cacat kaki yang berasal dari reseksi onkologi melanoma. Penelitian ini dilaksanakan dengan menggunakan pendekatan kualitatif deskriptif dan metode studi pustaka. Data yang digunakan di dalam penelitian ini berasal dari berbagai hasil penelitian dan studi terdahulu yang bersifat relevan dengan pembahasan penelitian. Hasil dari penelitian menemukan bahwa terdapat adanya beberapa tahapan penting dalam pelaksanaan Reverse Sural Flap untuk merekonstruksi kulit setelah operasi pengangkatan Melanoma Maligna. Tahapan-tahapan tersebut adalah diagnosis melalui anamnesis, pemeriksaan fisik, dermoskopi, dan histopatologi. Selanjutnya adalah tahap evaluasi untuk memastikan diagnosis, diikuti oleh pembedahan sesuai kebutuhan. Proses reverse sural flap bisa dilakukan setelah operasi melanoma selesai, dengan potensi komplikasi tergantung pada diagnosis dan pengobatan yang tepat waktu.
Selecting Hydraulic Fracturing Method for Wells Landed in Deep and Tight Gas Reservoirs
Authors: Xia K. , Mahood T. , Hassani S.
Published: November 2023

Many deep and tight gas reservoirs require hydraulic fracturing treatment to boost production, even though they are naturally fractured to some extent. In the oil and gas industry, different fracturing methods are generally used, which are named cased hole/clustered-perforation fracturing and openhole multistage stimulation methods. In practice, how to select the right fracturing method for a well landed in deep and tight reservoirs has rarely been discussed. Both fracturing methods can fail for deep and tight reservoirs, which leads to poor production performance. To solve this issue, a novel geomechanics workflow and some criteria are presented that can be used to select the right fracturing method for wells landed in deep and tight reservoirs. The key components of the novel geomechanics workflow will be briefly introduced, such as natural fractures prediction, a framework for calculating the breakdown pressure envelope and optimal perforation direction, 3D modeling of hydraulic fracture-natural fracture interaction, and fully coupled poroelastic model for openhole multistage fluid injection. The interactions between discrete natural fractures (NF) and propagating hydraulic fractures (HF) will be investigated through some modeling studies, which can exhibit the possible impact of natural fractures on hydraulic fractures propagation. Both advantages and disadvantages of the natural fractures’ role can be objectively visualized based on the resultant fracture network. Some guidelines for both openhole MSF (multistage fracturing) and cased hole perforation hydraulic fracturing treatment are also given in this paper.
Optimization of Hydraulic Stimulation Treatments of Tight Sandstone Gas Reservoirs in Oman with Geomechanical Sensitivity Analysis Using Analytical Simulation Techniques; A Case Study
Authors: Alyaaribi Aflah , Aamri Mohammed , Azim Mohamed Abdel , Hinai Khalid , Al-Ghaithi Ali
Published: November 2023

The development of Oman's tight gas accumulation is a multifaceted endeavor, characterized by the utilization of fractured vertical wells targeting a multitude of hydrocarbon units. Additionally, highly deviated to horizontal wells have been employed to access the most impermeable zones within these units. The intrinsic geomechanical, petrophysical, and lithological complexities within these tight units profoundly influence not only the distribution of fracture conductivity but also the efficiency of gas drainage from these fractured zones. This is evident through variations in mobility across the reservoir, ultimately impacting the collective gas production from all well architectures. To optimize hydraulic fracturing design and analysis, accurate predictions and calibration of formation breakdown pressure and minimum horizontal stress (Shmin) are imperative. Notably, it was observed that conventional mechanical earth models derived from sonic logs often fall short in realistically capturing the dynamic variations in minimum horizontal stress within these tight formations. Consequently, this study advocates the integration of diagnostic fracture injection tests (DFIT) within the same formation. These tests serve as a pivotal tool for the calibration of both breakdown pressure and minimum horizontal stress, ensuring a more precise and effective approach to tight gas accumulation development.
1D/3D Clustering Techniques of Geomechanical and Reservoir Properties to Overcome Stimulation Challenges
Authors: Hamid Osman , Alamer Sarah
Published: November 2023

Multi-stage hydraulic fracture in vertical and horizontal wells of extremely tight and unconventional reservoirs has become one of the main techniques to effectively create communication between the reservoir and the wellbore to enhance hydrocarbon flow; there is a need to integrate all available parameters to address the stimulation challenges. This study aims to construct fully integrated models to improve completion and stimulation operations using 1D/3D clustering techniques for all available properties.

1D/3D modeling approaches will be used to cluster geomechanical, geological, drilling, and reservoir parameters using Agglomerate Hierarchical clustering techniques that provide an innovative 1D/3D composite product that is used to overcome stimulation operational challenges. This approach provides strong guidelines and effective solutions for the formation fracability and injectivity-related issues facing completion and stimulation operations.

These techniques will increase confidence in stimulation modeling that provides clear guidance to develop strategies for completion and stimulation operations to maximize hydrocarbon production.

The results of 1D clustering techniques provide a composite log highlighted in the color code of the breakdown pressure and identify the best interval for stimulation and perforation operations. In contrast, the 3D clustering provides a stimulation index (SI), that enables users to identify the best sweet-spot interval within the study area, which improves stimulation requirements.

These models have been proven successful in the selection of the frac stages, yet they can be optimized for all other operations. This model opened the doors for long-term studies when coupled with the dynamic model.
Experimental Study on Indoor Multi-Cluster Fracturing Based on Distributed Fibre-Optical Monitoring
Authors: Wang Su , Chen Mian , Chang Zhi , Zhang Qixing , Lv Jiaxin , Cui Zhuang , Hou Bing
Published: November 2023

Hydraulic fracturing is an important stimulation technique for unconventional oil and gas fields, and real-time monitoring of fractures technology is crucial to evaluate the result of reservoir stimulation. This paper combines distributed sensing equipment based on OFDR with large-scale true triaxial fracturing physical simulation equipment. Then, the laboratory single-cluster and multiple-cluster hydraulic fracturing physical simulation experiments were carried out, while conducted real-time fracture monitoring using bare optical fibre. The experimental results indicate that the location and sequence of fractures initiation can be determined based on the strain evolution of the optical fibre. The general law of fracture propagation on fibre strain evolution can be obtained in single-cluster hydraulic fracturing experiments. In addition to determine the sequence and location of fractures initiation, multi-cluster experiments can also observe the mutual influence of different fractures, and the amount of liquid entering each fractures. These laboratory hydraulic fracturing experiments by distributed optical fibre sensing were conducted under true triaxial conditions, which can provide reference and guidance for on-site oilfield fracturing design.
Modeling Horseshoe Wells Performance in Unconventional Plays
Authors: Merzoug A. , Dehdouh A. , Ouadi H. , Alghawi Y.
Published: November 2023

The development of unconventional plays often presents unique challenges, such as drilling through overpressured zones with narrow mud windows. A prime example is the Inyan Kara formation in the Bakken, where operators have had to add additional casing to drill safely, incurring extra costs of approximately half a million dollars per well. In the Permian Basin, a different challenge arises due to lease constraints, which limit drilling to a square mile, resulting in horizontal wells with short laterals of 5,000 ft. To mitigate these issues, novel drilling techniques have been adopted, such as the U-shape well design first implemented by Shell in 2019. This design, featuring one vertical section and two laterals connected by a U-turn, has been increasingly utilized to reduce risks associated with drilling in shallow formations while allowing for extended lateral lengths of up to 12,000 ft. However, a comprehensive evaluation of the performance of these wells has been lacking in the literature. This study presents a numerical modeling analysis of U-shape wells, using a well-calibrated model of the Bakken formation. The model, built on a fully coupled physics-based simulator, incorporates reservoir, fractures, and wellbore data, enabling a nuanced understanding of multiphase flow and pressure losses. The study compares the performance of U-shape wells with conventional wells in unconventional plays over a 30-year period, considering total oil production. The results indicate that U-shape wells, on average, have longer fracture lengths towards unstimulated regions compared to two horizontal wells, due to the dissipation of stress shadow when moving from heel to toe. This effect enhances the performance of U-shape wells. Furthermore, when comparing two U-shape wells with four conventional wells, the performance was found to be similar. This study provides valuable insights into the potential of U-shape wells as a viable solution for drilling in unconventional plays.
Estimation of the Mechanical Parameters of a Mining Rock Mass Based on Resistivity Detection
Authors: Wang Chao , Li Hongze , Zhang Yujie , Feng Jili
Published: November 2023

In this paper, resistivity is employed to estimate the mechanical parameters of disturbed rock masses. The relation between resistivity and mechanical parameters is clarified by the damage variables based on resistivity and the interrelation among logging physical parameters. Such a relation is further mathematically expressed and verified by experiments and numerical simulations. To apply the proposed method for the stability evaluation of coal mine goaf sites, a calculation framework for the mechanical parameters of the mining rock mass is developed. Based on this framework, the in situ overburden mechanical parameters are obtained by resistivity detection, while the stability evaluation of abandoned goaf sites is performed together with FLAC3D. The results show that there is a reasonable relation between the mechanical parameters of the rock mass and resistivity, which is a linear negative relation between the mechanical parameters and the resistivity proportional coefficient. The goaf site is stable through both numerical results and in situ monitoring data. Additionally, it is demonstrated that the proposed method to calculate mechanical parameters by resistivity is of paramount significance to rock mass engineering.
Sensitivity Analysis of the Factors Affecting Formation Breakdown Pressure Using a Computational-Based Approach
Authors: Almani Tameem , Alquhaidan Yousef , Khan Khaqan
Published: November 2023

In hydraulic fracturing operations, formation breakdown pressure is the pressure at which the fracture initiates. This corresponds to the peak pressure at which the fracture opens as a result of injecting a drilling fluid at a very high pressure (Ito and Hayashi, 1991; Ito, 2008). An accurate estimation of this value remains an open problem due to several reasons, one of which is the dependance of this value on different underlying physical parameters. The criticality of this parameter stems from the fact that it drives how much horsepower is needed on site: overestimating it leads to expenditure loss and underestimating it lead to operation failure. In this work, we will perform a sensitivity analysis on the several factors affecting the formation breakdown pressure value. We will utilize the computational framework developed in (Almani et al. 2021 (1,2)) which computes the breakdown pressure as a function of all the underlying physical parameters including in situ stresses, drilling fluid related parameters, and rock mechanics parameters. The ultimate objective is to determine the significance of every input parameter on the corresponding breakdown pressure.
Possible Scenarios of CO2 Injection Through a Thermal Induced Fracture Predicted by an Analytical Model
Authors: Su K. , Dechelette B. , Pujol G.
Published: November 2023

The multidisciplinary studies in the project phase of CO2 storage in depleted sandstone reservoir raised a lot of questions, one of these is related to the risk of thermal induced fractures (TIF) leading to a sustained injectivity increase. What is the consequence of such induced fracture on bottom hole flowing pressure (BHFP)? Does the CO2 flow will concentrate inside the fracture leading to propagation further and further of the TIF? To answer these questions, this paper presents an analytical solution of pressure at bottom hole with supposed constant hydraulic aperture of a TIF. The masse balance equation of CO2 flow with consideration of leak-off through fracture walls is solved explicitly. This solution enables us to assess the range of BHFP for various injection rate and fracture opening scenarios. Typically for an injection at 20 bpm, the BHFP could reach 310 bars. The maximum length of the fracture influenced by CO2 flow is affected by the assumptions made regarding the hydraulic aperture of the TIF and the characteristic time (τ) applied in the calculation of the leak-off coefficient. This range spans from 40 meters to 250 meters.
Integral System of Monitoring and Modeling for Rock Fragmentation and Blast Vibration
Authors: Yang R.
Published: November 2023

Most mines seek fine fragmentation for down-stream operations to maximize mineral abstraction with minimized energy cost. On the other hand, maintaining stable highwalls and undisturbed nearby community is highly desirable. To obtain fine fragmentation, it is often required to design blasts with favorable energy concentration through explosive loading or blasthole delay timing. Such blast designs have potential to cause high blast vibration in general. A blast optimization requires a desirable fragment size distribution as well as controlled blast vibration at concerned locations. To achieve the optimization, an integral system for accurate monitoring and reliable modeling of full blast design parameters for rock fragmentation and blast vibration is required. Current technology in the literature falls short for each of the needs. This paper presents an integral system, which includes three indispensable components for blast monitoring and modeling, which together complete a close loop of the needs for blast optimization.
Experimental Study and 3D Numerical Analysis of Wellbore Instability in Naturally Fractured Formations
Authors: Wei Yaoran , Li Xiaorong , Tan Zhenlai , Yang Tianyu , Su Feiyu , Feng Yongcun
Published: November 2023

Exploration and development of fractured formations is difficult, because complex conditions such as stuck pipe, wellbore collapse, and even the loss of borehole intervals occur frequently, causing huge economic losses and affecting the later drilling operations. However, most of the existing literature on wellbore stability analysis in fractured formations focuses on the coupled effects of fluid flow and deformation, and the impact of three-dimensional natural fracture characteristics (roughness, dip angle, etc.) on wellbore instability is not yet closely examined, which may yield significant errors and misleading predictions. This paper carried out a series of experiments to analyze the shale sample's fracture characteristics and shear strength. Then, a fully coupled 3D hydro-mechanical model was then constructed using the distinct element method (DEM) to investigate the wellbore instability. Finally, a comprehensive parametric study was performed to analyze the effects of characteristics of fractures (e.g., distribution density, surface roughness and associated shear strength, and dip angle) on wellbore stability under different in-situ stress states. The results show that the increase of the number of parallel weak surfaces results in a larger radial displacement around the wellbore. Fracture roughness poses an important impact on wellbore stability because larger fracture roughness is associated with higher rock shear strength. As the dip angle of the weak plane increases, the maximum wellbore displacement increases and then decreases, and the peak displacement occurs at the dip angle of 45°, which is more obvious in a normal fault stress regime. This research results provide a useful tool to understand and assess the effect of natural fracture characteristics on wellbore instability for drilling design in fractured formations.
Quantitative Prediction of Tectonic Fractures in the Fourth Member of the Leikoupo Formation in the Pengzhou Area, Sichuan Basin
Authors: Yang Xu , Bai Mingsheng , Xie Qiang , Li Gao , Shangguan Ziran
Published: November 2023

This paper aims to highlight the fracture characteristics of the fourth member of the Leikoupo Formation in the Pengzhou area. An anisotropic fracture density model considering the fracture attitude was established to predict tectonic fractures quantitatively. The results indicated that the maximum and minimum principal stresses experienced during the Himalayan Period were mainly concentrated in 120–150, and 85–100 MPa, respectively. The fracture strike can be grouped into NEE, NE, NWW, NW, nearly SN, and nearly EW trending. Three typical fracture development areas were determined: fault zone, anticline core, and others. The high value of vertical linear density was chiefly concentrated in the north and southwest of the study area and around the fault. The high value of the maximum horizontal linear density was primarily concentrated in the center of the study area. In addition, the vertical linear density of the anticline core was relatively low, but the horizontal density was relatively high, resulting in high gas productivity in these areas. Considering that the core area of the anticline included in the A-5 platform is the largest and the corresponding horizontal linear density is high, it is suggested that future wells be made in the A-5 platform.
Successful Pilot Deployment of Wellbore Strengthening Design Criteria and Quantification of Enhanced Fracture Gradient in a Depleted Reservoir in Malay Basin
Authors: Tan C. P. , Razak M. S. , Zakaria S. S. , Abitalhah A. , Zainudin W.N.S. Wan Mohd
Published: November 2023

Comprehensive large scale laboratory test data was used to develop fracture gradient enhancement technology for drilling mud compounds. Based on the laboratory test data, correlations were developed between optimum compound particle size against Young’s modulus of the rock and generated fracture width to maximise the wellbore strengthening performance of the compounds. In addition, Enhanced Fracture Gradient (EFG) concept and criteria were developed for the compounds to widen the stable mud weight window, and a niche workflow was developed for utilisation of the wellbore strengthening design criteria. The workflow was deployed and validated in the pilot deployment of the correlations and EFG criteria in two wells for drilling through depleted reservoir in Malay Basin. The EFG was predicted and incorporated into the mud weight programme and mud loss contingency plan of the wells. The wells were drilled with 10 ppb of the optimum mud compounds and the concentration was monitored and maintained throughout the drilling. In the first well, the maximum ECD exceeded the in-situ fracture gradient of the depleted reservoir by 1 ppg without any losses. Following TD of the hole section, an open-hole leak-off test was conducted which validated the predicted average EFG of 1.8 ppg above the in-situ fracture gradient. The predicted EFG was within 0.2-0.3 ppg from the open-hole leak-off test value. In the second well, the depleted reservoir was exposed to 0.6 ppg above the in-situ fracture gradient and no losses were observed. The successful deployment in the two wells validated the design criteria and guidelines for maximising wellbore strengthening performance of optimum mud compounds and the quantification of EFG for widening the stable mud weight window for safe and efficient drilling, especially in depleted reservoirs. The quantification of the wellbore strengthening and predicted EFG in advance enable their proactive incorporation into the well programme design and operation.
Fracture Morphology Evaluation of Surrogate Model for Fast Prediction Using Machine Learning
Authors: Hu Zhongyu , Sheng Mao , Wei Zhaoyang , Tian Shouceng , Zhou Jun , Hu Shimeng
Published: November 2023

Fracture morphology is the fundamental data to optimize hydraulic fracturing design. However, the physical modeling and simulation is time consuming involving data preparation, model parameter setting and validation, time-consuming running. Machine Learning (ML) methods have the potential to integrate multi-source data and enhance calculation efficiency, thus enable to be critically useful in fracture morphology prediction. This paper aims to create a ML-based surrogate model for quick fracture morphology prediction. The approach involves the numerical simulation of hydraulic fracturing in two blocks wells, the combination of geological and engineering parameters to be a dataset. Particularly, the pumping time-series data were integrated by encoding and the Conditional Generative Adversarial Networks were used to expand the samples in order to enhance the model's capabilities. Following this, the correlation and principal component analyses were used for the feature engineering to identify key factors for stimulation effectiveness and surrogate model inputs. The comparative analysis demonstrated the excellent predictive ability of the fused Recurrent Neural Network and Multi-Layer Perceptron model, reducing validation set errors by approximately 15%. This work demonstrates the feasibility of ML-based surrogate models for predicting fracture morphology, with the advantages of fast, efficient and integrated multi-source data.
Effect of H2 on Salt Caverns During Fast Cycling Injection-Production: Laboratory Characterization & Storage Integrity Workflow
Authors: Younes J. , Ghafouri S.M. H. S. , Grasselli G.
Published: November 2023

The expanding global population and clean energy demand suggests utilizing renewable energy from sources such as wind, solar, biomass, geothermal, hydro and biofuel. The intermittent nature of such sources has propelled a need for efficient storage. Hydrogen (H2), being a carbon-free energy carrier, emerged as a potential solution, but it will require large volume to be stored to meet the demand. Underground hydrogen storage (UHS) is preferred given its low cost, tightness, and safety. Although existing UHS facilities have safely operated for over 40 years, the expected demand growth will require frequent injection-withdrawal cycles. This review provides an examination of the processes involved during H2 cycling. Firstly, the different cyclic tests are classified based on loading path, frequency, type and environment conditions. Then the behavior of rock salt under cyclic loading is discussed. Detailed attention is given to the chemical interaction between H2 and salt, covering experimental research concerning UHS in salt caverns. The review ends by presenting a laboratory experimental workflow involving the coupled processes within UHS operations.
The Effect of T Stress on Rock Crack Initial Fracture Properties
Authors: Junyu Liu , Yan Su , Tianyu Zhang , Shuting Wang
Published: November 2023

The traditional fracture criterion ignores the influence of non-singular term parameters when analyzing the crack tip initiation characteristics of rock. The results of I-II mixed mode fracture experiment show that after ignoring the influence of T stress, the results of crack initiation angle obtained by traditional fracture theory are different from those of experimental results. In this paper, based on the scaled boundary finite element method (SBFEM), the singular parameters I and II stress intensity factors and T stress at the crack tip of composite rock are extracted. The traditional fracture criterion is modified by considering the non-singular parameter T stress. The initiation characteristics of rock under different crack forms are studied and compared with the existing experimental and theoretical results. The results show that the crack propagation will be intensified when the T stress is positive, and the crack propagation will be inhibited when the T stress is negative. It can be seen that the influence of the non-singular parameter of the crack tip, that is, the T stress, cannot be ignored.
Carbonate Formation Pressure Prediction Method Based on Machine Learning
Authors: Tao Zhenyu , Fan Honghai , Liu Yuhan , Zhou Fei , Chen Yiwei
Published: November 2023

Formation pore pressure is the pressure of fluid in the formation pore, which is an important parameter in oil and gas well engineering. It is related to the design of the well structure, drilling fluid density, and the supporting use of casing pipe. Accurate prediction of formation pore pressure contributes to achieving safe drilling. However, due to the complex geology of carbonate rock formation, it is difficult to predict. This paper presents a prediction method for carbonate formation pore pressure based on machine learning. This method first analyzes the causes of abnormal formation pore pressure in the Block X and selects the Fan comprehensive interpretation method and the grey correlation degree method as the theoretical basis to determine the correlation between formation pore pressure and different well-logs. Through the Back propagation neural network method, the relationship between formation pore pressure and well-logs is established, and the prediction results have higher accuracy than the original model. Compared with the measured data, the error is less than 5%, which meets the needs of engineering. Compared with traditional methods, this method has strong applicability and greatly improves the accuracy of prediction, which is suitable for the pressure prediction of multiple genesis in carbonate rock formation.
Assessing the Feasibility of Above Injection Zone Pressure Monitoring of CO2 Geologic Storage in the Williston Basin, North Dakota, USA
Authors: Chellal Hichem A. K. , Malki Mohammed Lamine , Egenhoff Sven
Published: November 2023

This study evaluates the feasibility of above injection zone pressure monitoring (AIZ pressure monitoring) in one of the Williston Basin CO2 storage projects. This approach relies on reservoir flow-geomechanics coupled simulations to predict the pressure response in the AIZ in the case of perfect seal and hypothetical scenarios where CO2 leakage occurs along the injector or nearby legacy wells. In this study the advantages and limitations of the pressure monitoring at AIZ were evaluated and we found that while this approach is capable of accurate and early detection of CO2 leakage, it is recommended to be implemented with other direct monitoring methods as it has its limitations as was seen in two simulation cases with low permeability leakage pathways that allowed CO2 to slowly migrate to the monitoring formation without causing significant pressure changes in this later which would make such leaks undetectable if pressure monitoring is the only monitoring technique implemented in the storage complex.
Relationship Between Geomechanical Properties and Rock Wetting Behavior
Authors: Isah Abubakar , Mahmoud Mohamed , Aljawad Murtada Saleh , Arif Muhammad , Kamal Muhammad Shahzad
Published: November 2023

Although geomechanical properties primarily relate to the structural aspects of rocks, while wettability is predominantly associated with surface properties, there can be a connection or interrelation between these two aspects. Rock mechanical properties, including unconfined compressive strength (UCS), surface hardness, Young's modulus, and Poisson's ratio, can be correlated to rock wettability via contact angle measurements through various interconnected mechanisms. This could be through fluid penetration and seepage which affect the ability of fluids to infiltrate the rock matrix. Moreover, mechanical properties are associated to porosity, permeability, and pore structure and connectivity of rocks which could also affect wettability. Overall, the relationship between geomechanical properties and wettability is intricate and requires comprehensive investigation. Therefore, in this work, we investigated the relationship between geomechanical properties and rock wettability via contact angle and Amott index. Both sandstone and carbonate samples were assessed. The contact angle measurements were conducted at reservoir temperature (353 K) and pressures (0.1 to 50 MPa) using drop shape analyzer, and the wettability results were compared with Amott tests under similar conditions. The findings indicate a correlation between the wetting behavior of the rocks, as measured by the contact angle, and its mechanical properties. Rocks with lower values of UCS, surface hardness, and Young's modulus tend to have higher values of Poisson's ratio, leading to lower contact angles and a more water-wet behavior, suggesting an interconnection between these properties. However, the Amott index does not indicate this relationship. In addition, increase in pressure causes a slight reduction in the contact angles observed in the oil/brine/rock systems. Thus, understanding the relationship between rock mechanical properties and wettability requires considering the combined influence of fluid penetration, and geomechanical and stress-induced effects. It is essential to integrate these factors to gain comprehensive insights into the complex behavior of fluid-rock interactions and its implications for various geological and engineering applications.
Pengaruh Store Atmosphere dan Hedonic Shopping Terhadap Impulse Buying
Authors: Monica Andi Anggi , Astaginy Niar , Hendrik Hendrik
Published: November 2023

This study aims to determine the effect of store atmosphere and hedonic shopping on impulse buying in consumers of MR DIY Kolaka stores. This research is a quantitative study with an eksolanatory research approach using a questionnaire as an instrument. The population in this study were all consumers of MR DIY Kolaka stores with 120 respondents using purposive sampling technique, namely the technique of determining certain criteria. Testing research instruments using validity tests and reliability tests with SPSS 25.0. The data analysis technique used in this study is the measurement model test (outer model) and structural model testing (inner model) with Smart PLS 4.0. Based on the results of the study, it is known that there is a positive and significant influence between the Store Atmosphere variable on Impulse Buying at MR.DIY Kolaka Store Consumers, which is indicated by the t-statistic value of 4.293 with a P-Value of 0.000. While the Hedonic Shopping variable on Impulse Buying in MR.DIY Store consumers has a positive and significant effect, which is indicated by the t-statistic value of 5.792 with a P-Value of 0.000.