bluuebunny/crossref_metadata_2025 huggingface dataset:
Self-care differences in COVID-19 pandemic situation
Authors: Sari Ni Putu Wulan Purnama , Artsanthia Jintana
Published: June 2022

Introduction: Coronavirus Disease-2019 (COVID-19) pandemic has been happening for years now and no one can guarantee when this situation will end. The best thing that we can do in this new normal era is doing different self-care activity than what we usually do before the pandemic. This study aimed to analyze self-care differences before and after pandemic situation in the general population.

Methods: This cross-sectional study involved 645 respondents living in five congested communities in Surabaya, Indonesia. Sample was enrolled by means of cluster random sampling. Variables on this study was self-care activities related to new normal activies among community. Valid and reliable questionnaire of self-care activities was used in data collection. Independent sample t test was used in data analysis.

Results: Most respondents were female (54.6%) in their productive age (29.7 ± 11.5 y.o.), graduated (77.8%), private employee (35.5%), having no income (45.7%), and live with more than 3-5 family members at home (43.4%). Before pandemic, self-care was mostly sufficient (21.8 ± 5.9). After pandemic, self-care was improved greatly but still in sufficient level (28.5 ± 4.8). There was a significant self care difference before and after pandemic situation in the general population (p = 0.000).

Conclusions:
Self-care activities changes significantly after COVID-19 pandemic situation in the general population, but it was still in unoptimal level. Efforts to improve individual self-care in new normal era are needed to ensure this activity is implemented in its optimal level.
The Role of Thromboelastography in Heparin Therapy for COVID-19 Patients
Authors: Butar Yosua Butar , Hernaningsih Yetti , Yusoff Narazah Mohd
Published: June 2022

The 2019 coronavirus disease (COVID-19)-associated coagulopathy one of the significant complications often found in hospitalized COVID-19 patients. A hypercoagulable and prothrombotic state characterize coagulopathy with an increased risk of thrombotic events. Abnormal coagulation tests could predict bleeding risk, thrombosis, and disease severity. In addition to increasing the D-dimer, prolonged prothrombin time has decreased survival and increased treatment requirements. Based on laboratory findings, it was reported that 70% of patients with COVID-19 had disseminated intravascular coagulation (DIC) and 30% had thrombosis. Approximately 8% of patients with COVID-19 have hemorrhagic complications, the most common one is gastrointestinal bleeding. Variations in hypercoagulability and bleeding occur in COVID-19 patients. Therefore, the anticoagulant drug should be considered to minimize bleeding risk. An anti-bleeding agent for bleeding complications should be considered for the potential increase of coagulopathy. Thromboelastography (TEG) is a tool that is used to analyze the characteristics of viscoelastic clots, platelet function, and fibrinolysis in whole blood, providing a complete picture of the patient's coagulation status. From various therapeutic guidelines for COVID-19 patients, heparin is used as an anticoagulant drug to prevent thrombosis in COVID-19 patients. Starting from prophylactic doses to therapeutic doses, heparin is used to prevent the severity of COVID-19 patient course. The effect of coagulation on COVID-19 patients varies from no impact to hypercoagulation in TEG results.
The Use of Mask in Respiratory Exercise in the Era of COVID-19 Pandemic
Authors: Djajalaksana Susanthy , Listyoko Aditya Sri , Harjantho Lucky Togihon , Christanto Anthony , Falyani Silvy Amalia , Yamasaki Akira
Published: June 2022

Introduction: The 2019 Coronavirus Disease (COVID-19) pandemic causes public health protocols to be strictly enforced. This may disrupt the willingness to practice sports and/or exercises due to the requirement of masks, which may be uncomfortable and limiting for some people. However, masks are not an obstacle for someone to exercise. Moreover, some exercises, including respiratory-focused ones, are known to be particularly beneficial for one’s health. This study examined the effect of using masks on performing exercises, particularly respiratory exercises, in the era of COVID-19 pandemic.
Methods: A total of 24 people participated in this study using randomization and cross over techniques. The variables measured were respiratory rate, oxygen (O2) saturation, pulse rate, carbon monoxide (CO) levels, and fatigue scale using the Borg Breathless Score. Statistical test used independent t test, Wilcoxon, and Mann-Whitney U with a difference level of p < 0.05.
Results: There was no significant difference between the observed parameters (heart rate, respiratory rate, peripheral O2 saturation, CO levels, and Borg scale) in the groups using masks and not using masks.
Conclusion: The increase in pulse rate, respiratory rate, and Borg Scale in the aerobic phase of respiratory exercise is physiological and can improve significantly after the cooling phase.
Lung Function and Respiratory Symptoms Features of Smoker among University Students
Authors: Zacharia Nathaniel Jason , Damayanti Triya , Wibowo Adityo
Published: June 2022

Introduction: Smoking habit still becomes one of the problems in Indonesia with the high number of active smokers in university students. Smoking is one of the causes of several conditions of respiratory symptoms and risk factor of multiple case of lung function impairment. This study aimed to examine characteristic of lung function and respiratory symptoms and its relationship in active smokers among university student in Depok, Indonesia.
Methods: This was a cross-sectional study using American Thoracic Society (ATS) questionnaire for respiratory symptoms and Brinkman index for smoking habits. Lung function was examined using EasyOne® Air Spirometer.
Results: This study was participated by 116 male university students who are active smokers. This study found that majority of respondents fell into the mild category of smoking habit (96.56%) and complained of respiratory symptoms (74.14%). This study found lung function impairment in 15.5% respondents (8.6% obstructive and 6.9% restrictive disorder). There was no significant relationship between smoking habits with respiratory symptoms and lung function impairment among respondents.
Conclusion: This study found the characteristics of smoking habits in male university students were categorized as mild smoking habit, followed by the appearance of respiratory symptoms and lung function impairment. However, there was no significant relationship between smoking habits and respiratory symptoms or lung function. This issue needs to be paid attention to strengthen the campaign to prevent smoking initiation and to help smoking cessation among young adults as early as possible.
Association of IL-6 rs1800796 Gene Polymorphism on Susceptibility to Pulmonary Tuberculosis
Authors: Kristiani Maria , Sugiri Yani Jane , Chozin Iin Nor , Setiyowati Nanik , Listyoko Aditya Sri
Published: June 2022

Introduction: Tuberculosis (TB) is still the leading cause of mortality and morbidity around the globe, particularly in underdeveloped nations. Indonesia is listed as the country with the second-largest TB burden in the world according to Global TB Report 2020. Only 10% of those infected with Mycobacterium tuberculosis (MTB) develop active TB and the great majority continues to stay latently infected, indicating that the host response to MTB may be genetically controlled at each stage. A growing number of studies have shown that numerous host genetic variables have a role in TB susceptibility. IL-6 is a pro-inflammatory cytokine produced by monocytes, endothelial cells, and fibroblasts that stimulates B and T lymphocytes while also controlling the immune response to TB. This study investigated the association of IL-6 rs1800796 gene polymorphism on susceptibility to pulmonary TB in drug-sensitive (DS) or drug-resistant (DR) patients.
Methods: The case-control study involved 71 cases and 34 controls. Blood samples were taken from all study participants at Dr. Saiful Anwar General Hospital, Malang between August 2020 and February 2021. To determine SNPs, blood samples were used in a genotyping investigation using the PCR-Multiplex technique.
Results: The genotype association of IL-6 rs1800796 (G/G, G/C, C/C) and allele frequency for patients and controls of IL-6 rs1800796 with susceptibility to pulmonary TB were insignificant (p > 0.05).
Conclusion: This study found no evidence of association of IL-6 rs1800796 gene polymorphism with susceptibility to pulmonary TB.
Detection of SARS-CoV-2 Delta Variant of Concern AY.57 and Clinical Characteristics of Imported Cases on a Vietnamese Coal Carrier Vessel in East Kalimantan, Indonesia: A Case Report
Authors: Marwan Marwan , Winardi Wira , Mu'ti Abdul , Wahyuni Sri , Jatmiko Ridmawan Wahyu , Alfian Donni Irfandi , Nur Muhammad Ikhwan , Sewu Satria
Published: June 2022

Introduction: The 2019 Coronavirus Diseases (COVID-19) continues to be a severe public health issue throughout the world. Disease transmission channels exist across all modes of transportation, including land, air, and water. The presence of this disease has been demonstrated by a study conducted in South Korea, which discovered that 90% of ship passengers have also been tested with SARS-CoV-2 virus.
Case: At the port of Samarinda, real-time polymerase chain reaction (RT-PCR) testing was performed on 20 Vietnamese coal carrier vessel crew members. According to the findings obtained from the RT-PCR test, every single member of the team had been infected with the virus. Since they exhibited symptoms of an infection caused by SARS-CoV-2 virus (such as coughing, fever, and shortness of breath), a total of 6 members had to be taken to the hospital. According to the results of genomic sequencing, the crew members were found to be infected with SARS-CoV-2 virus and variant of concern (VOC) of Delta AY.57, Vietnam lineage.
Conclusion: COVID-19 can be transmitted via public transportation, including land, air, and sea travel. Controlling the spread of the virus requires RT-PCR testing at terminals, stations, and ports. SARS-CoV-2 Delta variant is still dominating Southeast Asia region, particulary Delta VOC AY.57.
Precision surgery for primary liver cancer
Authors: Takamoto Takeshi , Makuuchi Masatoshi
Published: June 2022

Liver resection remains the best curative option for primary liver cancer, such as hepatocellular carcinoma (HCC) and intrahepatic cholangiocarcinoma. In particular, in liver resection for HCC, anatomical resection of the tumor-bearing segments is highly recommended to eradicate the intrahepatic metastases spreading through portal venous branches. Anatomical liver resection, including anatomical segmentectomy and subsegmentectomy using the dye-injection method, is technically demanding and requires experience for completion of a precise procedure. The recent development of imaging studies and new computer technologies has allowed for the preoperative design of the operative procedure, intraoperative navigation, and postoperative quality evaluation of the anatomical liver resection. Although these new technologies are related to the progress of artificial intelligence, the actual operative procedure is still performed as human-hand work. A precise anatomical liver resection still requires meticulous exposure of the boundary of hepatic venous tributaries with deep knowledge of liver anatomy and utilization of intraoperative ultrasonography.
LumbarNet: A Deep Learning Network for the Automated Detection of Lumbar Spondylolisthesis From X-Ray Images
Authors: Trinh Giam Minh , Shao Hao-Chiang , Hsieh Kevin Li-Chun , Lee Ching-Yu , Liu Hsiao-Wei , Lai Chen-Wei , Chou Sen-Yi , Tsai Pei-I , Chen Kuan-Jen , Chang Fang-Chieh , Wu Meng-Huang , Huang Tsung-Jen
Published: June 2022

A common spinal condition, spondylolisthesis is the presence of a relative back or forth displacement between the upper and lower vertebra due to one vertebra being oriented away from the smooth curvature of a normal spine. Aging-related illnesses such as degenerative spondylolisthesis are especially burdensome on social welfare and health-care systems in an aging society, especially radiologists and clinical physicians. Therefore, we proposed a computer aided diagnosis algorithm, named LumbarNet, for vertebral slippage detection on clinical X-ray images. Collaborating with i) a P-grade, ii) a piecewise slope detection scheme, and iii) a dynamic shift detection routine, LumbarNet was thus specialized for analyzing complex structural patterns in lumbar spine X-ray images and outcompeted other U-Net based methods. Extensive experiments on lumbar spine X-ray images in standard clinical practices showed that LumbarNet achieved a mean intersection over union value of 0.88 in vertebral region detection and an accuracy of 88.83% in vertebral slippage detection.
Harvesting Context and Mining Emotions Related to Olfactory Cultural Heritage
Authors: Massri M.Besher , Novalija Inna , Mladenić Dunja , Brank Janez , Da Silva Sara Graça , Marrouch Natasza , Murteira Carla , Hürriyetoğlu Ali , Šircelj Beno
Published: June 2022

This paper presents an Artificial Intelligence approach to mining context and emotions related to olfactory cultural heritage narratives, in particular to fairy tales. We provide an overview of the role of smell and emotions in literature, as well as highlight the importance of olfactory experience and emotions from psychology and linguistic perspectives. We introduce a methodology for extracting smells and emotions from text, as well as demonstrate the context-based visualizations related to smells and emotions implemented in a novel Smell Tracker tool. The evaluation is performed using a collection of fairy tales from Grimm and Andersen. We find out that fairy tales often connect smell with emotional charge of situations. The experimental results show that we can detect smells and emotions with F1 score of 92.7 and 79.2, respectively.
Genotype Uniformity, Wild Bird-to-Poultry Transmissions, and Farm-to-Farm Carryover during the Spread of Highly Pathogenic Avian Influenza H5N8 in the Czech Republic in 2021
Authors: Nagy Alexander , Černíková Lenka , Stará Martina , Hofmannová Lada , Sedlák Kamil
Published: June 2022

In 2020-2021, the second massive dissemination of a highly-pathogenic avian influenza (HPAI) of H5Nx subtype occurred in Europe. During this period, the virus caused numerous outbreaks in poultry, including in the Czech Republic. In the present study, we provide an insight into the genetic variability of the Czech/2021 (CZE/2021) H5N8 viruses to determine the relationships between strains from wild and domestic poultry and to infer transmission routes between the affected flocks of commercial poultry. For this purpose, whole genome sequencing and phylogenetic analysis of 70 H5N8 HPAI genomes representing 79.7% of the cases were performed. All CZE/2021 H5N8 viruses belonged to the 2.3.4.4b H5 lineage and circulated without reassortment, retaining the A/chicken/Iraq/1/2020 H5N8-like genotype constellation. Phylogenetic analysis suggested frequent local transmission of H5N8 HPAI from wild birds to minor poultry and extensive farm-to-farm spread among commercial poultry farms. In addition, the analysis suggested one cross-border transmission event. Indirect transmission via contaminated materials was considered the most likely source of infection. Improved biosecurity and increased collaboration between the field veterinarians and the laboratory are essential to limit the local spread of the virus and to reveal and interrupt critical routes of infection.
Marine artificial reef (MAR) interference in artisanal fisheries in Brazil: use of traditional knowledge
Authors: ABREU Juliana Silva de , DI BENEDITTO Ana Paula Madeira , MARTINS Agnaldo Silva , ZAPPES Camilah Antunes
Published: June 2022

The aim of this study was to describe the traditional knowledge from artisanal fishermen related to marine artificial reef (MAR) ship Victory 8B and to identify possible changes in the fishery area after its installation. We performed single ethnographic interviews (n = 80) through a semistructured questionnaire, using participant observation, visual ethnography, and field diary recordings. All the interviewees were men from 27 to 77 years old, with low education levels and up to 60 years of experience in the fishery artisanal. Most of the interviewees (n = 71; 88.7%) recognize the presence of this MAR in the region and its role as a shelter for marine fauna and an attractor for species with commercial value. Even with fishery prohibition in the vicinity of MAR Victory 8B, most of the interviewees (n = 75; 93.7%) reported the practice in that area. According to the fishermen, the ship installation did not alter area the fishery, but the structure positively changed the activity by attracting more fish, increasing capture and profits. With that, from the perspective of the fishermen perception, MAR Victory 8B fulfilled its role in the enrichment of the fish stock and the conservation of marine biodiversity in the region.
Identification of Alteration-Mineralization in Skarn Deposit System based on Time-Domain Induced Polarization Method Approach in Kasihan Area, Pacitan, East Java
Authors: Seizarsyah Taufik , Setiahadiwibowo Ajimas Pascaning , Maskuri Firdaus , Sutarto Sutarto
Published: June 2022

This research was conducted in Kasihan, Pacitan, East Java with the aim of knowing the alteration zone and ore mineralization from mineral sediment systems based on the conductivity and resistivity of subsurface rocks in the study area. A geophysical method is needed to map area area area of the prospect of mineral deposits as well as mathematical models in the area research. One of the geophysical methods used in studies of mineral sediment cases is Time Domain Induced Polarization (TDIP). Measurement  of Time Domain Induced Polarization method done with configuration dipole-dipole which is arranged relatively straight northeast-southwest as much 2 tracks, with each track having the length of 260 m with an initial space of 20 m electrodes. Targets of the TDIP Method can describe subsurface conditions as far as 48 m. The position of mineralization in skarn deposits in the Time Domain Induced Polarization method at a depth of 25 m below the surface topography shown by high resistivity values >2000 Ωm and   >500 msec chargeability in dacite and limestone
Analysis of Coal Quality on Mining Front and Ship Loading in East Kalimantan Province
Authors: Amsah La Ode Muh Yazid , Kurnia L.M. Hilman , Malim Anna Irada La Ode
Published: June 2022

This study aims to determine the quality of coal on the mining front and ship loading. The method used consists of literature study, sample collection and processing and data analysis using proximate analysis. The results of the analysis on the mining front obtained ash content 2.8%, total moisture 13.12%, volatile matter 39%, total sulfur 0.23%, fixed carbon 48%, calorie value 5.812 Kcal/Kg. On ship loading obtained ash content 3.89%, total moisture 14.15%, volatile matter 43.04%, fixed carbon 46%, total sulfur 0.25%, and calorie value 5.365 Kcal/Kg. The very different calorific value of 7.69% is influenced by changes in the total water content and ash content. This indicates a significant decline in coal quality.
Limit Equilibrium Method for the Slope Stability Analysis of Coal Mining at PT. Kalimantan Prima Nusantara
Authors: Ma’rief Al’Faizah , Hedianto Hedianto , Okviyani Nur , Mahyuni Enni Tri , Affan Abdul
Published: June 2022

Various problems on a slope can be influenced by several factors such as slope geometry and also the property value of the slope. The polemic regarding the exhibition conducted on the mining business license of PT. Kalimantan Prima Nusantara which has an area of 1500 hectares. PT. Kalimantan Prima Nusantara, there is a coal mining company located in Kapuas Regency, Central Kalimantan. The slope conditions in the mining area require attention to the stability of the slopes due to the lithological conditions of the research area found types of sedimentary rocks in terms of engineering geology or rock mass weathering class into the rock category. highly weathered – rock that is completely weathered. The purpose of this study is to analyze the mine slopes at GT-01 – GT-02 (South block pit) GT-03 – GT-04 (Central block pit), GT-05 – GT-06 (North block pit). The research used the balance limit method or the Bishop's method to see whether the shear strength on a slope (shear strength) has a high or low safety value. This is based on kinetic analysis by relying on inputs such as cohesion, bulk density, and internal shear angle. The results of this study indicate that the condition of the rock layers on the slopes are dominated by sedimentary materials such as claystone, siltstone and sandstone. The overall slope shows a slope angle of 35°-50 ° and based on the results of the analysis of the condition of the slopes on GT-01 to GT-06 it shows a stable condition with an average factor value of FK =>2.
Una interpretación sobre el bajo crecimiento económico en México
Authors: Sánchez Juárez Isaac Leobardo
Published: June 2022

Desde 1982 la economía mexicana se ha caracterizado por la presencia de bajas tasas de crecimiento económico, tal situación ha provocado una severa reducción del empleo y con ello del bienestar de la población mexicana. Siguiendo la concepción kaldoriana del desarrollo se supone que el proceso de estancamiento que sufre el país, sobre todo en los últimos años, se explica por la falta de dinamismo del sector manufacturero nacional. Esto último se atribuye, principalmente, al actual modelo económico, implementado a finales de los ochenta, y sus políticas asociadas. De no corregirse la actual política económica y aplicarse una política industrial estratégica, la economía seguirá estando sometida a un estancamiento estructural y a crisis recurrentes. La solución pasa por un cambio de modelo económico, en el marco de la economía de mercado, que privilegie el crecimiento y el empleo.
Combined Effect of Contact Area, Aperture Variation, and Fracture Connectivity on Fluid Flow through Three-Dimensional Rock Fracture Networks
Authors: Huang Na , Zhang Yubao , Yin Qian , Jiang Yujing , Liu Richeng
Published: June 2022

In order to investigate the combined effect of contact area, aperture variation, and fracture connectivity on the fluid flow through a fractured medium, a series of flow simulations were implemented on two types of three-dimensional discrete fracture network (3D DFN) models constituting fractures having spatially variable apertures and parallel plates, respectively. The flow tortuosity within the 3D DFN models was examined by changing the density, aperture distribution, and closure of fractures. The results show that compared with the 3D DFN models constituting parallel plates, the model with variable apertures provides more pronounced 3D preferential flow pathways. At the individual fracture scale, the preferential flow pathways mostly converge within the void spaces of large aperture, and at the network scale, they are located in the most transmissive fractures within the connected networks. The permeability of 3D DFNs depends not only on the contact area and aperture variation within individual fractures but also on the fracture connectivity and the contact at fracture intersections within the fracture network. Increasing the fracture connectivity tends to enhance the permeability, while increasing the contact at fracture intersections would significantly reduce the permeability. A correlation between the equivalent permeability of 3D DFNs constituting fractures with spatially variable apertures and parallel plates is proposed incorporating the effect of network-scale topology. A tortuosity factor for 3D DFNs is defined based on the proposed model, and it can account for two competing effects when the model is upscaled from individual fracture to fracture network: the permeability reduction induced by contact obstacles at fracture intersections and permeability enhancement induced by increasing the fracture connectivity.
Thermodynamic Model Evaluations for Hydrogen Pipeline Transportation
Authors: Cely Alexandra , Hammer Morten , Andersen Hilde , Yang Tao , Nekså Petter , Wilhelmsen Øivind
Published: June 2022

Equations of state and transport property models for hydrogen and hydrogen mixed with natural gas components relevant for pipeline transport have been evaluated by comparing to experimental data and reference equations of state. The evaluated properties are density, speed of sound, Joule-Thompson coefficient, the isobaric and isochoric heat capacity, viscosity, and thermal conductivity. A temperature span of −10 to 50 °C and a pressure span of 1-300 bara has been set as the target range for pipeline transport. Viscosity and thermal conductivity models have been evaluated for binaries where experimental data are available. The goal of this work was to determine if models already available in commercial simulators can predict fluid properties accurate enough for engineering purposes.

The classical cubic equations of state of Soave-Redich-Kwong (SRK) and Peng-Robinson (PR) with van der Waals mixing rules have been tested with parameters extracted from the common commercial simulations tools Hysys, Unisim, PVTsim Nova and Multifash. In general, the different parameter sets give similar performance. One exception is the H2-CH4 binary, where both Unisim and Multifash use a non-optimal kij interaction parameter. Neither the SRK, nor PR can describe the Joule-Thompson coefficient of hydrogen, and the error lies in the range 50%-100%. The Joule-Thompson coefficient is however small, and the effect of this misprediction on pipeline simulations might not be significant.

For viscosity and thermal conductivity predictions, the SuperTRAPP model in REFPROP 10 as well as simpler viscosity models LGE, LBC and a corresponding-state-principle model of PVTsim Nova have been evaluated. The SuperTRAPP model in REFPROP 10 was found to predict viscosity and thermal conductivity within a reasonable accuracy for pure hydrogen. The simpler viscosity models LGE and LBC overestimate the viscosity of hydrogen by 65% to 90% in the transport domain of interest. For the hydrogen binary systems studied, the SuperTRAPP model for the thermal conductivity and viscosity had errors around 20% at high pressures. Comparing corresponding-state-principle viscosity models with the SuperTRAPP model gave relative deviations in the range 3.9% to 13%. The SRK equation of state is found to perform better than the PR equation of state, with a relative density error below 1% for hydrogen rich systems.

A TIBCO Spotfire® visualization dashboard has been developed for easy access to the evaluation results of the large amount of data and thermodynamic models. A steady-state thermohydraulic analysis for Europipe (Norway to Europe) has been performed to evaluate the effect that using different equations of state and viscosity models have on the thermohydraulic estimations. After a review of the thermodynamic model's performance, clear guidance on model selection for hydrogen transportation is provided.
Stimulation of Conventional Geothermal Wells with Propped Fractures
Authors: Shaoul Josef R. , Park Jason , de Pater C. J.
Published: June 2022

Conventional hydrothermal ("low enthalpy") geothermal reservoirs are already being developed in the Netherlands as a source of heat for greenhouses, district heating. Many of these wells are left with a positive skin after being drilled, and could therefore benefit from stimulation. In order to evaluate the potential benefit of propped fracture stimulation for this type of reservoir, a history match of a real geothermal injection and production doublet was made using an industry standard 3D reservoir simulation model. This model was then used to perform production and injection forecasts for different completion scenarios, including propped fracturing.

All available data (logs, PLT, welltests) was used in creating and history matching the reservoir simulation model. The model was history matched to the individual welltests for both the production and injection well and to a 3 year data set of production and injection data. In order to match the long-term pressure trend, an increase in the size of the thermal fracture in the injection well was needed. The history matching results were compared to the predicted increase in the size of the thermal fracture using a new 3D FEM fracture model. The same model parameters were also used to design propped hydraulic fracturing treatments. The propped fractures were also placed in the reservoir simulation model for both the production and injection wells, to predict the performance of the wells with fracture stimulation.

Although the actual wells used in this study had negative skins to begin with (after drilling), many wells drilled in the same reservoir (Rotliegend in the Netherlands) have positive skins to begin with. Our simulations showed significant improvement in well injectivity and productivity using propped fractures, compared to a well with a typical initial skin of +2 seen in new open-hole wells in this reservoir. Injection pressure was also reduced significantly, to below the regulatory limits on "safe" injection. The new 3D FEM model showed that injection well thermal fracture propagation was strongly affected by small differences in the Young's modulus between the higher and lower porosity layers in the reservoir.

This paper shows, based on actual well data from a real geothermal doublet, the expected benefit from hydraulic fracture stimulation is significant, especially when the wells have a positive skin after drilling. The effect of small differences in rock stiffness on thermal fracture propagation in a geothermal injection well is also a new and surprising result.
Physics-Based Data-Driven Interwell Simulator for Waterflooding Optimization Considering Nonlinear Constraints
Authors: Li Ying , Nguyen Quang , Onur Mustafa
Published: June 2022

When nonlinear constraints such as field liquid and water production rate are imposed onto the problem and need to be honored, optimizing well controls such as producing bottom-hole pressures (BHPs) and injection rates becomes more challenging. Hence, the main objective of this paper is to present an efficient production optimization tool to handle nonlinear state constraints for well-control waterflooding optimization problems. The proposed efficient optimization tool uses our newly improved physics-based data-driven interwell waterflooding simulator (referred to as INSIM-BHP) that handles both rate and pressure controls. Our previous waterflooding optimization applications used an old version of INSIM which only considered the linear constraints and did not incorporate the correct well indices for computing BHPs in the case of well BHP control optimization. In this study, we use our newly developed interwell waterflooding simulator that removes the mentioned restrictions in well-control optimization to maximize the net-present-value (NPV) with nonlinear state constraints. We use a recently developed line-search sequential quadratic programming (LS-SQP) algorithm coupled with stochastic simplex approximate gradients (StoSAG). We tested our proposed methodology on a three-dimensional (3D) channelized reservoir with multi-segmented wells and compared it with a commercial simulator. Results show that our methodology provides optimal well controls that satisfy the specified nonlinear state constraints successfully. In addition, the optimal well controls and NPV obtained from our INSIM-based optimization method compare well with the corresponding results from a high-fidelity commercial reservoir simulator but in a far less computational time. The novelty of our work is its presentation of an improved physics-reduced data-driven proxy simulator (INSIM-BHP) to replace the high-fidelity simulators to simulate the oil saturation and pressures to perform computationally efficient well-control waterflooding optimization under nonlinear constraints.
A Deep-Learning-Based Approach for Production Forecast and Reservoir Evaluation for Shale Gas Wells with Complex Fracture Networks
Authors: Dong Peng , Liao Xinwei
Published: June 2022

This paper proposes a data-driven proxy model to effectively forecast the production of horizontal wells with complex fracture networks in shales. With the multilayer gated recurrent unit (GRU) cell, the proxy model is coupled with newly developed deep learning methods include attention mechanism (Att-GRU), skip connection, and cross-validation to deal with time series analysis (TSA) issue of multivariate operating and physical parameters. In the formulation, the input variables include time, variable bottom hole pressure (BHP), horizontal well length, fracture number, fracture half-length, and fracture conductivity and the output variable refers to the production corresponding to the forecast time. The sample data generated by the boundary element method (BEM) is used in the proxy model learning process. The shuffled cross-validation method is utilized to improve the model accuracy and generalization capability. Results depict that the Att-GRU can accurately forecast the production for shale gas wells with complex fracture networks at a given time and variable BHP while maintaining a high calculation efficiency. The operating and physical parameters analysis indicates that the Att-GRU has learned the underlying physical features of complex fracture networks and variable BHP. Case study from Marcellus shale shows that the proposed Att-GRU is robust in both production forecast and reservoir evaluation, and it is a potential proxy model for transient analysis.
IAST Modelling of Competitive Adsorption, Diffusion and Thermodynamics for CO2-ECBM Process
Authors: Asif Mohammad , Wang Lei , Hazlett Randy , Serikov Galymzhan
Published: June 2022

Objective/Scope

The CO2 emission is one of the main causes for the global warming and it may be controlled by sequestrating CO2 into the geological formation. The coalbed formation provides a dual advantage for CO2 sequestration as CO2 may be stored in coal forever with enhancing the coalbed methane recovery. Thus, the cost of CO2 sequestration may be offset completely or partially. The main objective of the paper was to comprehend the CO2-ECBM displacement using the three concepts viz. competitive adsorption, diffusion, and thermodynamic modelling of coal

Methods, procedure, and process

In this paper, the pure gas isotherm on coal for CH4, and CO2 was evaluated using manometric method. The binary gas isotherm or competitive adsorption was studied using IAST modelling. MATLAB code was developed for the solution of IAST model and Newton Raphson approach was followed. The IAST modelling was done by taking 50%/%50 mole fraction of CH4/CO2. By analyzing the binary gas isotherm, the optimum injection pressure was evaluated. On the same injection pressure, co adsorption isotherm was drawn at different mole fraction of CO2 in gas phase. Separation factor was calculated by taking ratio of CO2 and CH4 in the gas and adsorbed phase respectively. Furthermore, adsorption data was used for discussing the sorption kinetics in coal and diffusion coefficient was evaluated. Furthermore, the thermodynamic parameters were also calculated and integrated with above noted parameters for the methane displacement in CO2-ECBM process.

Results, observations, and calculations

The CO2-ECBM displacement is very much dependent on the competitive adsorption and diffusion process in coal. The surface potential and Henry constant are important parameters for defining the CO2-ECBM displacement. The coadsorption isotherm was drawn at the optimum injection pressure and it shows that methane displacement would be the optimum by taking 11 %/89% mole fraction of CO2 and CH4 for two temperatures i.e., 288 K, 308 K. It is identified through diffusion regime that diffusion coefficient for the binary gas isotherm is the average of the diffusion coefficients of pure CO2 and CH4.

Novel/Additive information

This is the first kind of study which provides the completely integrated approach for describing the methane displacement in CO2-ECBM process. This novel study promotes our understanding of the complex mechanisms of CO2-ECBM displacement process.
Miscibility Study of Flue Gases for a Coupled CCS-EOR Project
Authors: Gonzalez-Perez Alfonso , Barrado Manuel , Pardo Rosario Rodriguez , Ruiz Jesus Montes
Published: June 2022

Miscible hydrocarbon (HC) rich gas injection is a common EOR technique included in the development plan of many Abu Dhabi oil fields. This technology, that provides a very high oil recovery, requires the supply of a gas that is very valuable for other uses or its commercialization. Utilization and storage of flue gases rich in CO2 and N2 can play a key role in lowering the overall reservoir emissions by coupling carbon capture and storage (CCS) with EOR techniques. Thus, the substitution of hydrocarbon gas by these gases is of great environmental and industrial interest. Nevertheless, the change of the injection gas is not straightforward and requires a previous study to ensure the gas miscibility.

The aim of this piece of research is to estimate the minimum miscibility pressure (MMP) of the studied gas, in order to clarify if miscibility conditions are achieved at reservoir pressure. Thus, a comprehensive study was performed applying three different approaches to predict/estimate the MMP:

Empirical correlations from the literature based on experimental results. Experimental measurements with Slim Tube tests. Computer modeling based on equations of state for phase-behavior calculations.

Miscibility of CO2 and N2 was successfully investigated through the three approaches. In the case of CO2, miscibility at reservoir pressure was totally ensured at 120°C since MMP was estimated to be the bubble pressure of the studied oil, more than 100 bar below reservoir pressure. Otherwise, the conclusion of the nitrogen miscibility studies is that N2 gas flooding is not a feasible EOR technique since MMP is far above reservoir pressure. Before completely discarding the use of nitrogen, miscibility of mixtures of HC rich gas and N2 was first studied by PVT simulations. Thermodynamic modelling was compared against experimental Slim Tube tests evaluating HC+N2 mixtures. Laboratory work led to conclude that mixtures with 42% of N2 could be injected at miscible conditions and revealed that simulations overestimate the minimum miscibility pressure of the studied gas mixtures. Finally, miscibility of CO2 and N2 mixtures with typical compositions of flue gases from post-combustion processes were studied using the thermodynamic model retuned with previous experimental measurements.

This work presents a thorough study of minimum miscibility pressure of CO2 and N2 in oil from Abu Dhabi, which is the first step of any EOR project coupled with CCS. The developed methodology covered the three different approaches and the results provide a broad comparison amongst correlated, measured and simulated MMP.
A Practical Approach to Maximise UGS Storage Efficiency in Order to Secure Energy Supply
Authors: Li Limin , Yu Huijuan , Kshirsagar Atul , Samy Ayman , Mao Chuanqin , Qu Lin , Kuswiranto Agung , Gui Feng , Cook Dave
Published: June 2022

The Underground Gas Storage (UGS) working gas capacity is one of the important design parameters for a UGS project. The objective of this paper is to demonstrate a case study from Sichuan area, China, where a fractured carbonate gas reservoir was used for UGS and show the key factors that should be considered to optimize UGS working gas capacity and help to secure energy supply during peak season.

The dynamic simulation model was history matched on both depletion and storage. This model was coupled with 4D Geomechanics effects. It was then employed to capture the key parameters that will affect the working gas capacity. Based on the 4D Geomechanical integrity and facility assessment results, the forecast model was created using the subsurface and surface facility constraints. The study workflow included setting up the forecast model, uncertainty analysis and sensitivity analysis to capture the key driving parameters for the working gas volume. This study also included sensitivities of emergency gas supply during peak winter season.

This study showed that the main factors that determine the UGS working gas capacity are the initial gas in place, tubing head pressure (THP) during withdrawal phase, bottom hole pressure (BHP) during injection phase, well pattern and well count. It was observed that each injection/production cycle is affected by the previous cycles. The simulation showed that the incremental working gas volume represented as a trend can be better fitted by a power function with both THP and BHP. It also demonstrated that lowering the THP limitation is more effective than increasing the BHP limitation. However, this may require surface facility upgrading. The optimum operating condition was identified by considering all engineering and geomechanical constrains such as erosion, wellbore integrity and cap rock integrity. This is used to guide the UGS daily operations with optimum production/injection rate of each well in a safe manner. The study recommended to implement a stepwise strategy to reach the working gas capacity.

This paper presents a novel practical workflow and methodology to implement increased UGS reservoir working capacity. It also provides a practical way to forecast the operational pressure range and quickly predict the deliverability of emergency gas supply under various market demands.
A Universal Method for Predicting the Relative Permeability Data of Low Salinity Injection
Authors: Aljaberi Abdulla , Aghabozorgi Shokoufeh , Sohrabi Mehran
Published: June 2022

Low salinity waterflood (LSWF) injection is an enhanced oil recovery (EOR) method proven effective through extensive experimental studies. Correct implementation of this method in reservoir-scale simulations requires reliable estimation of changes in relative permeability data associated with LSWF. For this purpose, a few models have been suggested based on geochemical interactions, such as the cation exchange capacity of clay, which are case dependent and cannot be applied to all systems.

This study presents a novel semi-empirical model based on incremental oil recovery measured during low salinity injection. Therefore, it can be applied to all rock types, fluid systems, and wettability conditions regardless of the active mechanism. Some mechanisms proposed in the literature relate the additional oil recovery during low salinity injection to measurable parameters such as micro-dispersion. As a result, the kr curves can be constructed using this new methodology by measuring the micro-dispersion.

This method has been validated against five sets of secondary and tertiary coreflood experiments published in the literature. First, the high salinity kr data is obtained by history matching using the CMOST module of CMG software. Then the proposed method and the measured value of additional oil recovery were used to estimate the kr data of low salinity injection. The results showed that the suggested method could predict the oil recovery and pressure drop in secondary and tertiary modes. The high-salinity relative permeability was shifted towards a more water-wet condition in tertiary mode. The kr curve of secondary LSWF showed a significant shift towards a more water-wet condition than tertiary mode, implying lower residual oil saturation. Since the additional oil recovery versus micro-dispersion curve was reported for this rock sample, one can simply predict the kr values of LSWF for other values of micro-dispersion.

Due to the ongoing debate regarding the dominant mechanism during LSWF, there is no universal model for estimating the relative permeability of LSWF in all systems. The model presented in this paper provides a powerful tool for engineers to simulate the LSWF kr data in both tertiary and secondary flooding regardless of the active mechanism.
Implementation of Streamline Derived Rate Targets Improved Oil Production of Mature Field
Authors: Adamson Scott , Giden Ilhami , Matzka-Pöll Ronald
Published: June 2022

The application and implementation of streamline derived rate targets have proven to increase oil production and reduce water cut with minimal investment (Kornberger & Thiele, 2014). The Matzen field, and in particular the 16.TH layer, has significant peripheral water injection as well as a large operating range on the production and injection wells, making it an ideal candidate for streamline based water flood optimization measures.

A multidisciplinary approach was taken to modelling the 16.TH, incorporating and analyzing data including pressures, production & injection volumes as well as individual well operational envelopes. Several uncertainties surrounding the field were also addressed in the modelling approach, for example faults and their transmissibilities. As a result, robust streamline derived rate targets could be defined and implemented across approximately 30% of the active wells in the field (around 60 wells), which significantly improved the production performance.

Following implementation, the performance was continuously monitored, with impressive results. Implementation of the rate targets, resulted in a field wide daily production rate increase of up to 5%, peaking at 26 m3/day (165 boe/day) with an increase of only 140 m3/day on the liquid production and an increase of 160 m3/day water injection, exceptional for a field with an average water cut of 98%.

Despite the positive results, there were several lessons learned that are discussed in the paper and can be applied to future field implementation to improve the performance further.

It has been again proven that implementation of streamline derived rate targets can provide significant value, and through a defined workflow and automatic model updates this value can be realized faster, more reliably and with less manpower, offering an effective method of managing a water flooded asset and maximizing its value.
Seismicity Induced by Cooling of CCS Reservoirs
Authors: Berentsen Cas , de Pater C. Hans
Published: June 2022

CO2 injection into depleted gas fields involves long term cooling of the reservoir. Therefore, even if injection pressure is relatively small, the cooled volume still creates an extensive stress disturbance that can lead to changes in the shear and normal stress on faults. Destabilization of the faults will be especially strong when the cold front reaches a bounding (sealing) fault. Modelling the stress evolution provides an estimate of this effect and its timing.

Induced seismicity due to CO2 injection has been observed in some projects. In the Netherlands, depleted gas reservoirs are used for storage, where faults can be critically stressed due to depletion compaction. Modelling methods of induced seismicity that were developed for gas production and storage can be beneficial for deep CCS projects, where potential leakage of stored fluids along activated faults is the main concern.

Since CO2 injection may induce large thermal fractures, it is important to include thermal fracturing in the analysis of seismic risk since the pressure and temperature field may be influenced by the propagating thermal fractures.

A geomechanical model is used to forecast seismicity risk. Benchmarking the model on the observed data is critical for validating the geomechanical modelling. Even in the absence of observed seismicity, the model can show the maximum slippage area that could occur, so that the extent of enhanced fault transmissibility can be bounded.