bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Analysis of Permeability Influence on CO2 Plume based on Reservoir Simulation
Authors: Lo Julian , Komara Eki , Utama Widya 
Published: July 2024

Abstract
Permeability is critical in site characterization and geoscience studies for carbon capture and storage projects. There is significant uncertainty of CO2 movement in the subsurface caused by permeability. This study aims to analyze the influence of permeability on the movement of CO2 plumes using a synthetic single-porosity model based on reservoir simulation. By simplifying geomechanics, employing tornado experimental design, as well as utilizing Pearson and Spearman correlations from 30,000 neural network proxy models based on Latin Hypercube and Monte Carlo experimental design, this research successfully explains the impact of permeability on CO2 movement. The reservoir can withstand pressures up to 6500 psi without rock failure. The total CO2 injection with a 90% probability is ∼1.3 TSCF equivalent, with an injection rate of 30 MMSCFD, optimized for a duration of 120 years. Initially, the CO2 movement tends to be upward during injection due to gravitational effects, but over time, it tends to move laterally. Vertical permeability exhibits a negative correlation with total CO2 injection, lateral distribution of CO2 plumes, and CO2 solubility in water. On the other hand, horizontal permeability shows a positive correlation with total CO2 injection. Factors such as perforation location and layer thickness also influence the extent of permeability’s role. However, the lateral and vertical movement of CO2 in this study has not been fully identified, and more complex quantification formulas are needed in commercial simulators. Despite the limitations in data and computational resources, this research successfully explains the movement of CO2 plumes and highlights the importance of other factors such as porosity, perforation location, layer thickness, among others. The recommendations of this study include the use of more complex quantification formulas to model the movement of CO2 plumes, along with increasing the complexity of the model.
Petrological and mineralogical characteristics of “red material layer” in Patuha geothermal field, Bandung, West Java
Authors: Pradana E P A , Setiawan N I , Sesesega R S 
Published: July 2024

Abstract
Patuha Geothermal Field is located in Ciwidey, Bandung, West Java Province, with a total resource potential of approximately 400 Mwe (Megawatt electric). With such potential, seven power plants have been developed in Unit-1, capable of producing 60 MWe of electricity, and are currently being developed in stages for Unit-2. In the development of the Unit-2 power plant, there was a problem where collapse occurred around the drill hole area, especially since the color of the material that came out during drilling was red. We call this material the red material layer (a layer composed of red material). This problem also occurs in Unit-1. This research aims to characterize the type of red material layer to see why this problem occurs in this layer. We studied the petrological and mineralogical characteristics of the red material layer by cutting rock samples from six drill holes in Unit-1. The analytical methods used were megascopic observation, petrography, and XRD (X-ray diffraction) to determine the mineral content texture and identify the material’s origin, including clay minerals, alteration, and oxidation mineral aggregates. The petrological and mineralogical analysis found that the red-colored material is dominated by hematite, with some samples containing magnetite. We found four characteristic types of red layer material and four types of textures that appeared in iron oxide minerals: rim, vein, matrix replacements, and fragment replacements. We conclude from the visible vein texture that oxidation occurs due to oxygen penetration through gaps of a fault/fracture/joint. This oxidizes the area around the vein and then undergoes hydrothermal change. Meanwhile, those that do not have a vein texture are considered material resulting from an oxidation process on the surface, which is then deposited and undergoes hydrothermal change to contain oxide minerals such as hematite and magnetite. Apart from that, XRD observations also found high amounts of clay minerals such as chlorite, smectite, kaolinite, illite-smectite mixed layers, and chlorite-smectite mixed layers. The presence of these clay minerals is thought to cause a collapse in the area around the drill hole because its swelling and exfoliation properties are reactive to fluids, especially drilling fluids.
Petrology and geochemistry of Mount Lurus lavas: evidence for alkaline to subalkaline transition in the rear arc of Java, Sunda Arc
Authors: Mumtaza T H , Handini E , Hasenaka T , Mori Y , Khasanah T N 
Published: July 2024

Abstract
Mount Lurus, a small Quaternary volcanic center in the rear of Java Island, Sunda arc, has erupted both alkaline and subalkaline lavas in a short span of active period. Furthermore, this small volcanic edifice, together with its neighboring alkaline volcanic center of Ringgit-Beser, corresponds to a shallower slab depth (∼160 km) than Muria in Central Java (270 km). We report the mineralogical and geochemical characteristics of Lurus lavas and compare them to the Ringgit-Beser lavas. All Lurus lavas show typical characteristics of island arcs with elevated Ba, Sr, Pb, and K and negative anomalies of Nb and Ti. The older Lurus edifice (Old Lurus) produces alkaline lavas with high alkalinity, which are trachyandesite and phonotephrite in composition. The younger Lurus (Young Lurus) generates calc-alkaline lavas with basaltic andesite composition. Both groups have plagioclase, clinopyroxene, olivine, and opaque minerals as phenocrysts phase. Leucite is found in one sample of Old Lurus with the lowest SiO2 content (48.92 wt%) and highest alkali content (5.38 wt%). Old Lurus lavas tend to show higher contents of incompatible elements (Pb, Ba, Nd, and Rb) than Young Lurus. The mineralogical and compositional differences between these lavas suggest that these magmas are sourced from at least three magma chambers of distinct composition: highly potassic magma chamber (comparable to the evolved-K series of Ringgit-Beser) and hydrous-potassic magma which fed Old Lurus edifice; and calc-alkaline magma chamber which fed Young Lurus edifice.
Geology and Ore Mineralization Characteristics of the Selodong Prospect, Lombok Island, Indonesia
Authors: Kirom N , Idrus A , Setijadji L D , Vanessa A 
Published: July 2024

Abstract
The Selodong prospect is located in the southwest sector of Lombok Island which tectonically lies within the W-E trending Sunda-Banda magmatic arc, which hosts various gold-base metal mineralizations including porphyry and epithermal deposits. Lombok Island, particularly southwestern portion of the island is known to hosts gold, silver and copper prospects, including Selodong prospect. The Selodong prospect is divided into several sub-prospect areas which include the Blongas, Montong Botek, Kekalik and Belikat. However, this study only focuses on the Blongas sub-prospect. The study is aimed to discusses the geology, characteristics of alteration and mineralization of the sub-prospect. To achieve the objective, some methods such as mapping and numerous laboratory works were conducted. Petrography to identify alteration minerals, ore microscopy to identify type of ore minerals, and fluid inclusion microthermometry to characterize ore fluid were performed. The geological conditions of the study area are composed of andesite lava, andesite breccia, diorite intrusion and alluvial deposit. Typical porphyry alteration type i.e., potassic is present. Argillic, silicic, advanced argillic, propylitic and phyllic alterations are also identified. The distribution of potassic and some argillic alteration is controlled by lithology, while silicic alteration, advanced argillic, propylitic and some argillic alterations are controlled by geological structures with an NW-SE and NE-SW trending patterns. Propylitic alteration is characterized by chlorite + epidote + calcite ± clay. Argillic alteration is marked by the presence of clay minerals such as clay + quartz. Advanced argillic alteration is typified by quartz + alunite + pyrolusite ± paragonite. Phyllic alteration is typified by sericite + quartz ± clay. Potassic alteration is marked by secondary biotite + quartz ± clay. Silicic alteration is marked by quartz + pyrolusite + epidote. Ore mineralization in the study area is associated with massive and stockwork vein textures. Ore and metalliferous minerals are found as magnetite, chalcopyrite, pyrite, hematite, goethite, jarosite, sphalerite, pyrrhotite, chalcocite and native gold. Generally, homogenization temperatures in the research area range from 543 - >600 °C, with salinity of 26.3 - 73.95 wt.% NaCl eq associated with potassic alteration, whereas homogenization temperatures range from 251 to 349 °C, with salinity of 5.46 - 8.38 wt.% NaCl eq. associated with silicic alteration. Based on those characteristics, the prospect in the study area indicates a porphyry deposit type, which is transition to high sulfidation epithermal.
Mineralogical and ore-fluid characteristics of the Onto Porphyry-HSE transition in Hu’u district, West Nusa Tenggara, Indonesia
Authors: Putra Z A M , Idrus A , Warmada I W 
Published: July 2024

Abstract
Onto prospect is located in the eastern part of Sumbawa Island in West Nusa Tenggara Province, Indonesia. The island is situated within the Sunda-Banda magmatic arc, which extends from west to east, consists of volcanic rocks from the early Miocene to the Holocene. Onto is one of the highly potential prospects and holds significant economic value among ore deposits in Indonesia. The aim of this research is to explain the geological setting and determine the genesis of mineralization based on petrographic, ore microscopic, and fluid inclusion analyses. Eight lithological units have been identified, namely early andesites, polymictic diatreme breccia, upper sedimentary package, caping andesite, quartz-phyric andesite sill, early porphyry, early intra-mineral porphyry, and late intra-mineral porphyry. Nine samples were analyzed for petrography to identify the alteration types consisting of illite-smectite, quartz-dickite, residual vuggy quartz, silicic, quartz-alunite, quartz-pyrophyllite±diaspore, potassic, phyllic-chloritic, and propylitic alterations. Additionally, pyrite, chalcopyrite, and covellite are predominantly present in the study area. Meanwhile, native gold is found as an inclusion in covellite and pyrite. From micro thermometric analysis of fluid inclusions in quartz veins associated with multiphase intrusive rocks, it is shown that the homogenization temperature of early porphyry ranges on average from 279°C to 377°C, early inter-mineral porphyry ranges from 263°C to 361°C, and late intra-mineral porphyry ranges from 275°C to 336°C. The salinity level of the measurements ranges from 5.71 to 10.27% by weight NaCl equivalent, with an average of approximately 8.15% by weight NaCl equivalent. The mineralization formation during the early or prograde phase is associated with the EDM vein system with a mineralization set of biotite-magnetite, digenite, chalcocite, and coevellite, type A veins with quartz-sulfides + anhydrite, M veins type associated with quartz-magnetite-chalcopyrite-bornite mineralization, AB veins type associated with quartz-sulfides + anhydrite textures, and B veins type with sulfide centerline characteristics. The mineralization system during the early stage is generally associated with potassic alteration (K-feldspar-magnetite-secondary biotite). Whereas the retrograde phase, the vein system is associated C veins type with sulfide mineralization groups consisting of massive chalcopyrite + quartz with phyllic alteration (quartz-muscovite-chlorite ± dickite), D veins type with quartz-pyrite+chalcopyrite associated with advanced argillic alteration (quartz-alunite-pyrophyllite ± diasporite), E veins representing the epithermal stage associated with minerals such as quartz-carbonates, galena, sphalerite, chalcopyrite, tetrahedrite-tennatite in the alteration stage of kaolinite-illite-smektite-sericite.
The Influence of Concrete Age on the Accuracy of Pile Integrity Testing on Bored Piles Foundation
Authors: Santoso H.T. , Hartono J. , Andani R. , Primaswari G. 
Published: July 2024

Abstract
Bored pile foundations are defined as deep foundations in the form of an elongated tube with a specific diameter made of reinforced concrete installed using the drilling method and in-situ casting concrete. The cast in-situ process in bored holes with a deep elevation below the ground surface can potentially cause integrity problems, such as voids, segregation, fracture, necking, bulging, and other concrete defects. Currently, many non-destructive test methods are available to ensure the quality of the bored pile; one is the Low Strain Integrity Testing method, also known as Pile Integrity Testing (PIT). ASTM recommends that PIT should be carried out no sooner than 7 days after casting or the strength of the concrete has reached a minimum of 75,0% of its design strength. In fact, the PIT test is carried out before the concrete’s age and/or its strength is achieved, considering the limited construction time. This could lead to misinterpretation of the PIT test results and inaccurate identification of the bored pile defect locations. The study aims to determine the effect of concrete age on the accuracy of bored pile defect locations on a laboratory scale. The test model consisted of four bored piles with a diameter of 0,3 meters and a depth of 2,0 meters, which were cast using reinforced concrete with a design strength of fc’ 30 MPa. The PIT was performed at <7, 14, and 28 days of concrete age, and then the confusion matrix method was used to create a binary classification model to determine the accuracy of the defect location. The defect locations were visually observed and validated by dismantling the test model after 28 days of casting. The results showed that the accuracy of identifying the location of concrete defects was not affected by the age of the concrete but was determined by the compressive strength of the concrete during testing. Referring to the F-score, bored piles with concrete strength >75,0% of the design accurately identify defect locations above 84,21%. On the other hand, bored piles with concrete strength <75,0% design resulted in accuracy below 66,67%.
Sequence Stratigraphy and Depositional Environment of the ‘Perahu’ Sand, Bekasap Formation, ‘DAP’ Field, Central Sumatera Basin
Authors: Putra M D A , Husein S , Multihadi  
Published: July 2024

Abstract
The ‘DAP’ Field is one of the oil and gas fields within the Central Sumatera Basin that is proven to have hydrocarbon reserves. One of the proven reservoirs in the ‘DAP’ Field is the ‘Perahu’ Sand, Bekasap Formation. This study aims to determine the depositional environment and facies distribution focusing on the ‘Perahu’ Sand, Bekasap Formation through a sequence stratigraphic approach. The research was based on an integrated analysis of sedimentary facies from one core data and a key well log to interpret the facies association. Then the key well is correlated to eight other well logs with the help of sequence stratigraphic concept to determine the depositional facies distribution and succession at the study interval. Lithofacies that are identified from core data were interpreted as floodplain, tidal channel, mud flat, mix flat, and sand flat, hence the depositional environment of ‘Perahu’ Sand was interpreted to be a tide-dominated estuarine. The parasequence set level of Bekasap Formation was interpreted to be in a transgressive system tract, with the ‘Perahu’ Sand divided into three flooding surfaces that is FS3, FS4, and FS5. The FS3 distribution consists of tidal-fluvial channel, crevasse splay and floodplain facies. The FS4 distribution consists of two tidal channels and one sand flat facies. The FS5 distribution consists of one sand flat facies. The depositional trend of the ‘Perahu’ Sand shows a northeast to southwest trend, with basinward toward southwest.
Sandstone facies distribution of potential reservoirs within lower talang akar formation in ‘Jasmine’ Field, Northwest Java Basin
Authors: Jasmine S R , Setyowiyoto J , Winardi S , Amrizal  
Published: July 2024

Abstract
‘Jasmine’ Field is an oil and gas field in the working area of a national oil company located in Northwest Java Basin. Lower Talang Akar Formation is considered to have one of the largest sandstone reservoir potentials in Northwest Java Basin based on earlier studies. This study aims to determine the depositional environment of Lower Talang Akar Formation and get the sandstone facies distribution of potential reservoirs in ‘Jasmine’ Field, as an early guideline for future production and drilling in new points within the field. Interpretation of this study was carried out by integrating 13 well log data, 13 well report data, 2 core data, and 1 3D seismic cube. Well log, well report, and core data were integrated to interpretate lithofacies, electrofacies, depositional environment, and stratigraphy sequence analysis. Sandstone body width vs. thickness ratio determination, fluid contact analysis, and RMS seismic attribute method were then carried to obtain the sandstone facies distribution of potential reservoir intervals of Talang Akar Formation in ‘Jasmine’ Field. The results shows that there are 2 intervals that has thick sandstone bodies as potential reservoirs in this study. The deposition direction for both Sandstone Body-A group and Sandstone Body-B group intervals is northeast-southwest. Sandstone Body-A group facies distribution is controlled by a braided river depositional environment and is distributed in the west side of the field. In the other hand, Sandstone Body-B group facies distribution is controlled by a distributary channel system in a lower delta-plain depositional environment and is distributed in both the west side and east side of the field.
Advancing the automated foraminifera fossil identification through scanning electron microscopy image classification: A convolutional neural network approach
Authors: Harbowo D G , Muliawati T 
Published: July 2024

Abstract
Handling more than thousand fossil foraminifera data is very challenging, especially for old-way identification. Determining morpho-taxonomy by conventional microscopic observation is very time-consuming and can lead to innacuracy identification. We are certain that the process could be advanced through big data analysis using a machine learning approach. Foraminifera fossils have already become a common standard for biostratigraphic proxies and paleoenvironmental interpretation. Therefore, the objective of this study was to develop an automated identification method using Convolutional Neural Networks (CNN). We used standardized Scanning Electron Microscopy (SEM) images of foraminifera acquired from various open-source databases for image classification. The analysis was conducted using Python programming language in Google Colaboratory. The image dataset is categorized based on its genus (n: 138) and divided into training and test/validation data for accuracy simulation (total image: 1833; data training: 1387; test/validation: 237/237). The best-fit accuracy values of the training-data and testing-data were between 97-86%:73-77%, with parameters including epoch number ranging up to 40, learning rates of 0.05, and a batch size of 64. These values indicate good prospects for foraminifera SEM Image taxonomic classification, demonstrating a noteworthy level of identification accuracy (63%). The outcomes of this study offer a new method for further effective automated morpho-taxonomic identification of foraminifera fossils using other conventional optic microscopy.
Evaluation of release wells for liquefaction mitigation using numerical simulation
Authors: Purbawati O , Faris F , Istiarto  
Published: July 2024

AbstractThe liquefaction phenomenon in sandy soil due to an increased pore-water pressure ratio during an earthquake can have significant consequences. The 2018 liquefaction event in Sibalaya, Central Sulawesi, highlights the need for mitigation measures to prevent similar incidents. This study evaluates the efficacy of constructing release wells along the Sibalaya segment of the Gumbasa irrigation canal to mitigate liquefaction using Standard Penetration Test data. The aim is to protect irrigation canal facilities and roads from recurrent flow liquefaction in Sibalaya. The release well is designed to rapidly dissipate the abnormally elevated pore water pressure that may occur during an earthquake. This study uses numerical simulations with the integration of Geostudio 2022.1 software, namelyQUAKE /WandSEEP /W. Simulation results comparing the Sibalaya location with and without the release well indicate that the latter is effective in preventing recurrent liquefaction in the Sibalaya region. Therefore, the construction of release wells is recommended as a viable mitigation measure against liquefaction.
Shallow groundwater quality around the area Kaligending final processing site in Kebumen Regency, Central Java Province
Authors: Widiyanto K , Raharjo P D , Hastria D , Puswanto E , Farisan A , Wibowo D A 
Published: July 2024

Abstract
The location of the Kaligending final Processing site is in Kraminan, Kaligending Village, Karangsambung District, Kebumen Regency which is the place for final waste processing. The Kaligending final processing site which is located in the hills can have an environmental impact on the area located below it. One of the impacts is the condition of groundwater in the area. The purpose of this study is to determine the condition and quality of shallow groundwater in the area. To find out groundwater conditions especially position and the pattern of shallow groundwater flow in the area is measured in the shallow ground water level which is then made a map of shallow groundwater and shallow groundwater flow direction patterns, while groundwater quality is measured by electrical conductivity and total dissolve solid (TDS) shallow groundwater in several wells. The results of the map pattern of shallow groundwater flow directions in the area come from the east and northeast, groundwater quality based on electrical conductivity is still suitable for use. The quality of shallow groundwater in residents’ wells in the Kraminan area is based on total dissolved solids, there are 4 wells that exceed the upper limit of drinking water quality standards (wells 3, 4, 5 and 6) which are located close to the Krembeng River