Pub Date : 2023-12-19DOI: 10.32693/bomg.38.2.2023.811
Septy Heltria, Amir Yarkhasy Yuliardi, Gentio Harsono, M. I. Joesidawati
The hydrodynamics of the Musi estuary ecosystem is influenced by the flow of water discharge from the river, tidal circulation within the estuary, and complex bathymetry. Numerical modeling is one of the best ways to explain the characteristics and processes occurring in the estuary. However, the obtained model requires validation to ensure its accuracy despite the complexity added by variability in tidal and bathymetric conditions, making the validation process more challenging. This difficulty can be overcome by using high-resolution data, which provides a refined understanding of the river-to-sea estuary flow and its variability. The validation process involves the use of conductivity-temperature-depth (CTD) instruments and mooring tidal stations. The validated model is considered capable of accurately simulating tidal propagation as it represents the temperature-salinity-density properties within the estuarine environment. The development of this model demonstrates the effective implementation of these parameters within the Musi estuary ecosystem domain. The 3D model simulation is used to consider the vertical discretization in the river-estuary-sea channel, which enhances the representation of temperature-salinity-density in the water column. The obtained results suggest that the 3D-MIKE modeling is well-suited for operational purposes, including the prediction of hydrodynamics and the management of estuarine areas, specifically in the Musi estuary ecosystem.
穆西河口生态系统的流体力学受到河流排水量、河口内潮汐环流和复杂水深的影响。数值模型是解释河口特征和过程的最佳方法之一。然而，尽管潮汐和水深条件的变化增加了模型的复杂性，但所获得的模型需要验证以确保其准确性，这使得验证过程更具挑战性。使用高分辨率数据可以克服这一困难，因为高分辨率数据可以提供对河口至海口水流及其变化的精细理解。验证过程包括使用电导率-温度-深度（CTD）仪器和系泊潮汐站。经过验证的模型能够准确模拟潮汐传播，因为它代表了河口环境中的温度-盐度-密度特性。该模型的开发展示了这些参数在穆西河口生态系统领域的有效应用。三维模型模拟考虑了河流-河口-海道的垂直离散性，从而增强了水体中温度-盐度-密度的代表性。所获得的结果表明，三维-MIKE 模型非常适合用于实际操作，包括水动力预测和河口地区的管理，特别是 Musi 河口生态系统。
{"title":"ASSESSMENT OF THREE-DIMENSIONAL BAROCLINIC CIRCULATION MODEL FOR THE MUSI COASTAL AREA","authors":"Septy Heltria, Amir Yarkhasy Yuliardi, Gentio Harsono, M. I. Joesidawati","doi":"10.32693/bomg.38.2.2023.811","DOIUrl":"https://doi.org/10.32693/bomg.38.2.2023.811","url":null,"abstract":"The hydrodynamics of the Musi estuary ecosystem is influenced by the flow of water discharge from the river, tidal circulation within the estuary, and complex bathymetry. Numerical modeling is one of the best ways to explain the characteristics and processes occurring in the estuary. However, the obtained model requires validation to ensure its accuracy despite the complexity added by variability in tidal and bathymetric conditions, making the validation process more challenging. This difficulty can be overcome by using high-resolution data, which provides a refined understanding of the river-to-sea estuary flow and its variability. The validation process involves the use of conductivity-temperature-depth (CTD) instruments and mooring tidal stations. The validated model is considered capable of accurately simulating tidal propagation as it represents the temperature-salinity-density properties within the estuarine environment. The development of this model demonstrates the effective implementation of these parameters within the Musi estuary ecosystem domain. The 3D model simulation is used to consider the vertical discretization in the river-estuary-sea channel, which enhances the representation of temperature-salinity-density in the water column. The obtained results suggest that the 3D-MIKE modeling is well-suited for operational purposes, including the prediction of hydrodynamics and the management of estuarine areas, specifically in the Musi estuary ecosystem.","PeriodicalId":31610,"journal":{"name":"Bulletin of the Marine Geology","volume":" 10","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138959959","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-07-25DOI: 10.32693/bomg.38.1.2023.818
Maulana Yusuf Ibrahim, Salma Dita Rysqi Puspita, Z. Syarafina, S. Zulivandama, E. Agustine
The acoustic impedance inversion seismic method, carried out at the "EL" well in East Java,provides a description of the physical properties of subsurface rocks. This method involves identifying rocklayers, lithology types, porosity values, the presence of hydrocarbons, and fluids in the target zone usingboth well data and integrated seismic data. The data processing included the cross-plotting of acousticimpedance (AI) with gamma ray logs, porosity logs, and resistivity logs. We integrated seismic and welldata, picked horizons, and created AI inversion models. The based model inversion technique was used tocompare the synthetic model with the seismic data, aiming to obtain an AI value that closely represents theactual model. AI seismic inversion effectively separates lithological boundaries vertically and laterally,based on the selected picking horizon and created model. To enhance understanding of the lithology andhydrocarbon prospect zone in the study area, a cross-plot analysis was used to correlate the seismic inversionmodel. The results reveal that the study area represents a hydrocarbon prospect zone, with reservoir rocksconsist of coral and foram at a depth range of 2320 - 2430 ft.
{"title":"LITHOLOGY AND RESERVOIR IDENTIFICATION IN THE “EL” WELL, EAST JAVA USING SEISMIC INVERSION","authors":"Maulana Yusuf Ibrahim, Salma Dita Rysqi Puspita, Z. Syarafina, S. Zulivandama, E. Agustine","doi":"10.32693/bomg.38.1.2023.818","DOIUrl":"https://doi.org/10.32693/bomg.38.1.2023.818","url":null,"abstract":"The acoustic impedance inversion seismic method, carried out at the \"EL\" well in East Java,provides a description of the physical properties of subsurface rocks. This method involves identifying rocklayers, lithology types, porosity values, the presence of hydrocarbons, and fluids in the target zone usingboth well data and integrated seismic data. The data processing included the cross-plotting of acousticimpedance (AI) with gamma ray logs, porosity logs, and resistivity logs. We integrated seismic and welldata, picked horizons, and created AI inversion models. The based model inversion technique was used tocompare the synthetic model with the seismic data, aiming to obtain an AI value that closely represents theactual model. AI seismic inversion effectively separates lithological boundaries vertically and laterally,based on the selected picking horizon and created model. To enhance understanding of the lithology andhydrocarbon prospect zone in the study area, a cross-plot analysis was used to correlate the seismic inversionmodel. The results reveal that the study area represents a hydrocarbon prospect zone, with reservoir rocksconsist of coral and foram at a depth range of 2320 - 2430 ft.","PeriodicalId":31610,"journal":{"name":"Bulletin of the Marine Geology","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41959474","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-06-30DOI: 10.32693/bomg.38.1.2023.803
D. Ralanarko, P. Nugroho, E. Sunardi, I. Syafri, B. Adhiperdana
Southeast Sumatra is a prolific oil and gas block located offshore in the Java Sea, 90 km north of Jakarta Bay. This area covers two major basins, namely Sunda Basin and Asri Basin. The initial development of the area focused on faulted and high closures and high-resistivity reservoirs. Further analysis shows that there are special low-resistivity reservoirs in Widuri Area, especially in the Aryani field. This paper will discuss the low resistivity pay zone reservoirs and fluid containment of the intervals. The paper will also include further assesment this undeveloped interval to increase oil production, considering the upside potential of the reservoirs using current geological, geophysical, and reservoir engineering approaches. Additionally, it will describe the operational challenges faced during the production period. The low-resistivity pay zone, a hydrocarbon-bearing reservoir in the Aryani field of the Widuri area, was identified using gas readings in the daily drilling reports, complemented with mud logging data. The Basal Sand interval, which drapes above the basement, was the site of the first producing well of Basal Sand, Aryani AC-X, preceded by a hydraulic fracturing job. Lambda-mu-rho inversion was implemented to delineate this reservoir. To recognize the potency in those wells, data reconfirmation was conducted between the elan summary, sidewall core, and cutting data. Aryani AC-X has successfully drained oil using a submersible pump, with an initial production of 408 bopd and cumulative production of 240 MBO.
{"title":"LOW RESISTIVITY PAY DEVELOPMENT: CASE STUDY OF TALANGAKAR FORMATION ASRI BASIN, OFFSHORE SOUTHEAST SUMATRA, INDONESIA","authors":"D. Ralanarko, P. Nugroho, E. Sunardi, I. Syafri, B. Adhiperdana","doi":"10.32693/bomg.38.1.2023.803","DOIUrl":"https://doi.org/10.32693/bomg.38.1.2023.803","url":null,"abstract":"Southeast Sumatra is a prolific oil and gas block located offshore in the Java Sea, 90 km north of Jakarta Bay. This area covers two major basins, namely Sunda Basin and Asri Basin. The initial development of the area focused on faulted and high closures and high-resistivity reservoirs. Further analysis shows that there are special low-resistivity reservoirs in Widuri Area, especially in the Aryani field. This paper will discuss the low resistivity pay zone reservoirs and fluid containment of the intervals. The paper will also include further assesment this undeveloped interval to increase oil production, considering the upside potential of the reservoirs using current geological, geophysical, and reservoir engineering approaches. Additionally, it will describe the operational challenges faced during the production period. The low-resistivity pay zone, a hydrocarbon-bearing reservoir in the Aryani field of the Widuri area, was identified using gas readings in the daily drilling reports, complemented with mud logging data. The Basal Sand interval, which drapes above the basement, was the site of the first producing well of Basal Sand, Aryani AC-X, preceded by a hydraulic fracturing job. Lambda-mu-rho inversion was implemented to delineate this reservoir. To recognize the potency in those wells, data reconfirmation was conducted between the elan summary, sidewall core, and cutting data. Aryani AC-X has successfully drained oil using a submersible pump, with an initial production of 408 bopd and cumulative production of 240 MBO.","PeriodicalId":31610,"journal":{"name":"Bulletin of the Marine Geology","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47364586","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-06-30DOI: 10.32693/bomg.38.1.2023.812
Subarsyah Subarsyah, Sahudin Sahudin
Cable power installation along the route with bedforms-sediment structures sometimes potentially to have problems in the future or near future. In order to mitigate the cable from exposure because of currents, it is important to know a detailed understanding of the seabed and its mobility. Seabed characteristics, either textures or sediment structures, could be interpreted from acoustic characters, one of which is based on sidescan sonar images. An automatic interpretation to classify seabed characteristics can be done by using an image processing software. Image processing has been done on sidescan sonar images along power cable route between Dumai and Rupat Island. The image processing was using simple textures and Grey-Level Co-occurrence Matrix (GCLM) textures. Manual interpretation of sidescan sonar images classifies the acoustic characters into six; (1) fine sand waves with ripple marks, wave length 2.5-4 meters, (2) fine sands, (3) fine sand waves with ripple marks, wave length 5-9 meters, (4) fine sand with ripple-mega ripples, (5) coarse sands with ripple-trawl marks, and (6) very fine sands. The results of automatic classification show that image processing with simple textures is unable to identify the textures and structures of sediments properly, but by combining simple texture classification and GCLM types of sediment textures and sediment structures are better identified. This classification results are in agreement with the results of manual interpretation of sidescan sonar images.
{"title":"ACOUSTIC CHARACTERISTICS OF SIDESCAN SONAR ALONG PROPOSED POWER CABLE ROUTE, DUMAI – RUPAT ISLAND","authors":"Subarsyah Subarsyah, Sahudin Sahudin","doi":"10.32693/bomg.38.1.2023.812","DOIUrl":"https://doi.org/10.32693/bomg.38.1.2023.812","url":null,"abstract":"Cable power installation along the route with bedforms-sediment structures sometimes potentially to have problems in the future or near future. In order to mitigate the cable from exposure because of currents, it is important to know a detailed understanding of the seabed and its mobility. Seabed characteristics, either textures or sediment structures, could be interpreted from acoustic characters, one of which is based on sidescan sonar images. An automatic interpretation to classify seabed characteristics can be done by using an image processing software. Image processing has been done on sidescan sonar images along power cable route between Dumai and Rupat Island. The image processing was using simple textures and Grey-Level Co-occurrence Matrix (GCLM) textures. Manual interpretation of sidescan sonar images classifies the acoustic characters into six; (1) fine sand waves with ripple marks, wave length 2.5-4 meters, (2) fine sands, (3) fine sand waves with ripple marks, wave length 5-9 meters, (4) fine sand with ripple-mega ripples, (5) coarse sands with ripple-trawl marks, and (6) very fine sands. The results of automatic classification show that image processing with simple textures is unable to identify the textures and structures of sediments properly, but by combining simple texture classification and GCLM types of sediment textures and sediment structures are better identified. This classification results are in agreement with the results of manual interpretation of sidescan sonar images.","PeriodicalId":31610,"journal":{"name":"Bulletin of the Marine Geology","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42086873","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-06-30DOI: 10.32693/bomg.38.1.2023.833
H. Nurfaidah, I. Setiadi, M. Sarkowi, O. Dewanto
The Sunda Asri Basin is dominated by normal faults and has little compressional structure. This basin consists of several depocenters with a thickness of up to 6000 m. Among the geophysical methods, gravity analysis has proven to be effective in determining the bedrock configuration and identifying sedimentary basins. This study aims to analyze sedimentary sub-basin patterns, basement height structures, faults, and bedrock configuration using trend surface analysis of polynomial filters. The analysis of polynomial filter show that a 10th-order anomaly yields optimal results. The high correlation value of 0.990925 provides the suitability of a 10th-order anomaly for qualitative interpretation. Spectral analysis results indicate an average bedrock depth of about 2.75 km within the Sunda Asri Basin. Furthermore, this analysis reveals the presence of 14 sedimentary sub-basin patterns in this area. The gravity modeling results indicate that the top layer has a density value of 2.37 g/cc, which interpreted as Pleistocene Tertiary sediment. The second layer consists of Tertiary-Miocene sediment with a density value of 2.28 g/cc, while the third layer comprises of Pre-Tertiary sedimentary rock at a density of 2.02 g /cc. The bottom layer of the model corresponds to metamorphic bedrock with a density 2.7 g/cc. SVD (Second Vertical Derivative) analysis successfully identified the presence of normal and thrust fault structures
{"title":"SUBSURFACE GEOLOGICAL INTERPRETATION OF THE NORTH SUNDA ASRI BASIN BASED ON SVD ANALYSIS AND GRAVITY ANOMALY MODELING","authors":"H. Nurfaidah, I. Setiadi, M. Sarkowi, O. Dewanto","doi":"10.32693/bomg.38.1.2023.833","DOIUrl":"https://doi.org/10.32693/bomg.38.1.2023.833","url":null,"abstract":"The Sunda Asri Basin is dominated by normal faults and has little compressional structure. This basin consists of several depocenters with a thickness of up to 6000 m. Among the geophysical methods, gravity analysis has proven to be effective in determining the bedrock configuration and identifying sedimentary basins. This study aims to analyze sedimentary sub-basin patterns, basement height structures, faults, and bedrock configuration using trend surface analysis of polynomial filters. The analysis of polynomial filter show that a 10th-order anomaly yields optimal results. The high correlation value of 0.990925 provides the suitability of a 10th-order anomaly for qualitative interpretation. Spectral analysis results indicate an average bedrock depth of about 2.75 km within the Sunda Asri Basin. Furthermore, this analysis reveals the presence of 14 sedimentary sub-basin patterns in this area. The gravity modeling results indicate that the top layer has a density value of 2.37 g/cc, which interpreted as Pleistocene Tertiary sediment. The second layer consists of Tertiary-Miocene sediment with a density value of 2.28 g/cc, while the third layer comprises of Pre-Tertiary sedimentary rock at a density of 2.02 g /cc. The bottom layer of the model corresponds to metamorphic bedrock with a density 2.7 g/cc. SVD (Second Vertical Derivative) analysis successfully identified the presence of normal and thrust fault structures","PeriodicalId":31610,"journal":{"name":"Bulletin of the Marine Geology","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46609811","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-06-21DOI: 10.32693/bomg.38.1.2023.789
Gisela Malya Asoka, Denny Nugroho Sugianto, Yani Permanawati
Ocean thermal energy conversion is an attempt to convert potential energy in the variances heat content of seawater into other energy by utilizing the temperature change between the sea surface and deep sea at least 20°C. The Lembata waters is near to the equator, sea surface temperature tends to be warm and stable. This research was conducted to estimate the potential energy generated from a closed cycle OTEC system in North Lembata Waters. This study used temperature data from Global Ocean Physics Reanalysis from Copernicus Marine Environment Monitoring Service (CMEMS) for 9 years (2012-2020) in 6 stations. Validation was performed using the primary CTD Lembata OTEC Team of the Marine Geological Institute (MGI). Temperature data validation results on the MSE (Mean Square Error), RMSE (Root Mean Square Error), and MAPE (Mean Absolute Percentage Error) methods are considered to represent field temperature conditions. The variability value shows the station point in the North Lembata Waters has a temperature with slight differences. The vertical temperature change (ΔT) shows between 20.98°C to 23.44°C. Potential electric power resulting from the OTEC system using the technical estimation formula. The average net power generated from those temperature gradients ranges from 5.65 MW-7.56 MW, respectively. The Lembata waters have temperature conditions suitable for OTEC installations. Station C-4 has a power potential of 6.84 MW with a depth of 763 m and the distance of 1.86 km from the coastline. Station C-4 in the Omesuri sub-district is the best point for OTEC installation in North Lembata Waters.
{"title":"STUDY OF POTENTIAL INSTALLATION OF OCEAN THERMAL ENERGY CONVERSION (OTEC) IN THE NORTH WATERS OF LEMBATA, NTT","authors":"Gisela Malya Asoka, Denny Nugroho Sugianto, Yani Permanawati","doi":"10.32693/bomg.38.1.2023.789","DOIUrl":"https://doi.org/10.32693/bomg.38.1.2023.789","url":null,"abstract":"Ocean thermal energy conversion is an attempt to convert potential energy in the variances heat content of seawater into other energy by utilizing the temperature change between the sea surface and deep sea at least 20°C. The Lembata waters is near to the equator, sea surface temperature tends to be warm and stable. This research was conducted to estimate the potential energy generated from a closed cycle OTEC system in North Lembata Waters. This study used temperature data from Global Ocean Physics Reanalysis from Copernicus Marine Environment Monitoring Service (CMEMS) for 9 years (2012-2020) in 6 stations. Validation was performed using the primary CTD Lembata OTEC Team of the Marine Geological Institute (MGI). Temperature data validation results on the MSE (Mean Square Error), RMSE (Root Mean Square Error), and MAPE (Mean Absolute Percentage Error) methods are considered to represent field temperature conditions. The variability value shows the station point in the North Lembata Waters has a temperature with slight differences. The vertical temperature change (ΔT) shows between 20.98°C to 23.44°C. Potential electric power resulting from the OTEC system using the technical estimation formula. The average net power generated from those temperature gradients ranges from 5.65 MW-7.56 MW, respectively. The Lembata waters have temperature conditions suitable for OTEC installations. Station C-4 has a power potential of 6.84 MW with a depth of 763 m and the distance of 1.86 km from the coastline. Station C-4 in the Omesuri sub-district is the best point for OTEC installation in North Lembata Waters.","PeriodicalId":31610,"journal":{"name":"Bulletin of the Marine Geology","volume":"114 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-06-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136356051","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-01-28DOI: 10.32693/bomg.37.2.2022.796
Eddy Mirnanda, Vera Sarah Simatupang, Harkins Prabowo
The South Sumatra Basin is a prolific oil and gas basin. The Tulung Selapan area, which is to the east and part of the South Sumatra Basin, is considered to have hydrocarbon potential. Several sub-basins, including the South Palembang and the North Palembang sub-basins, exist in the region. One of the geophysical methods for determining the presence of sedimentary sub-basins, structural patterns, and bedrock is the gravity method. The purpose of this study is to determine the structural pattern and interpret the subsurface geological model of the Tulung Selapan area using 2D modeling. The complete Bouguer anomaly (CBA) reveals circular and relatively northwest-southeast trending patterns, ranging from +33 mGal to +62 mGal. 2D gravity forward modeling results in eight successive rock layers. From top to bottom, the uppermost layer is swamp sediment with a mass density of 2.1 g/cm3, followed successively by the sedimentary rocks of the Kasai Formation (2.28 g/cm3), the Muara Enim Formation (2.32 g/cm3), the Air Benakat Formation (2.39 g/cm3), the Gumai Formation (2.3 g/cm3), the Baturaja Formation (2.48 g/cm3), and lastly a layer with a density of 2.7 g/cm3, which represents the bedrock. Due to the limited depth of 2800 m in 2D forward modeling, it is unable to identify the source and reservoir rocks. The seal rock (caprock) is interpreted to be shale from the Gumai Formation at an average depth of 1.53 km. Based on Second Vertical Derivative (SVD) analysis, 2D modeling identifies the presence of geological structures with normal faults.
{"title":"GEOLOGICAL INTERPRETATION OF 2D GRAVITY MODELING IN TULUNG SELAPAN AREA AND SURROUNDINGS, SOUTH SUMATRA BASIN","authors":"Eddy Mirnanda, Vera Sarah Simatupang, Harkins Prabowo","doi":"10.32693/bomg.37.2.2022.796","DOIUrl":"https://doi.org/10.32693/bomg.37.2.2022.796","url":null,"abstract":"The South Sumatra Basin is a prolific oil and gas basin. The Tulung Selapan area, which is to the east and part of the South Sumatra Basin, is considered to have hydrocarbon potential. Several sub-basins, including the South Palembang and the North Palembang sub-basins, exist in the region. One of the geophysical methods for determining the presence of sedimentary sub-basins, structural patterns, and bedrock is the gravity method. The purpose of this study is to determine the structural pattern and interpret the subsurface geological model of the Tulung Selapan area using 2D modeling. The complete Bouguer anomaly (CBA) reveals circular and relatively northwest-southeast trending patterns, ranging from +33 mGal to +62 mGal. 2D gravity forward modeling results in eight successive rock layers. From top to bottom, the uppermost layer is swamp sediment with a mass density of 2.1 g/cm3, followed successively by the sedimentary rocks of the Kasai Formation (2.28 g/cm3), the Muara Enim Formation (2.32 g/cm3), the Air Benakat Formation (2.39 g/cm3), the Gumai Formation (2.3 g/cm3), the Baturaja Formation (2.48 g/cm3), and lastly a layer with a density of 2.7 g/cm3, which represents the bedrock. Due to the limited depth of 2800 m in 2D forward modeling, it is unable to identify the source and reservoir rocks. The seal rock (caprock) is interpreted to be shale from the Gumai Formation at an average depth of 1.53 km. Based on Second Vertical Derivative (SVD) analysis, 2D modeling identifies the presence of geological structures with normal faults.","PeriodicalId":31610,"journal":{"name":"Bulletin of the Marine Geology","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43251684","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-01-08DOI: 10.32693/bomg.37.2.2022.788
Restu Ningsih, I. Setiadi, R. Rahardiawan, O. Dewanto, Rahmi Mulyasari
The offshore sedimentary basin of North Central Java is a marine basin located in the northern part of North Serayu Basin. This basin was formed through the uplift of the southern part of Central Java (Bumiayu) caused by the movement of a pair of horizontal faults. Studies of sub-basin delineation and basement configuration are rarely carried out in this basin. Therefore, the gravity method referring to subsurface-density variations was carried out to obtain this information. This research aims to delineate sedimentary basins and interpret the geological subsurface based on gravity data using spectral analysis, highpass and lowpass filters, also 2D gravity modeling. An average estimation depth to the basement in the study area of about 2.22 km was determined using spectral analysis. Qualitative analysis shows the basement-high pattern, sub-basin, and structure lineament patterns. The 2D model shows three layers consisting of the upper sedimentary layer of Tertiary-Neogene and the middle layer of Tertiary-Paleogene sediment with a density value of 2.3 gr/cc and 2.5 gr/cc, respectively. The lower layer has the highest density of 2.67 gr/cc, assumed as a granitic basement. The results of the Second Vertical Derivative (SVD) analysis on the residual anomaly cross-sectional paths indicate the presence of thrust and normal faults which can be used to assist the interpretation of fault structures in subsurface geological models. Gravity analysis of the offshore North Central Java sedimentary basin indicates the occurrence of sub-basins and geological structure patterns that considered as a potential zone for the development of the petroleum system in this area.
{"title":"GEOLOGICAL INTERPRETATION OF THE OFFSHORE SEDIMENTARY BASIN OF NORTH CENTRAL JAVA BASED ON SPECTRAL ANALYSIS AND 2D GRAVITY MODELING","authors":"Restu Ningsih, I. Setiadi, R. Rahardiawan, O. Dewanto, Rahmi Mulyasari","doi":"10.32693/bomg.37.2.2022.788","DOIUrl":"https://doi.org/10.32693/bomg.37.2.2022.788","url":null,"abstract":"The offshore sedimentary basin of North Central Java is a marine basin located in the northern part of North Serayu Basin. This basin was formed through the uplift of the southern part of Central Java (Bumiayu) caused by the movement of a pair of horizontal faults. Studies of sub-basin delineation and basement configuration are rarely carried out in this basin. Therefore, the gravity method referring to subsurface-density variations was carried out to obtain this information. This research aims to delineate sedimentary basins and interpret the geological subsurface based on gravity data using spectral analysis, highpass and lowpass filters, also 2D gravity modeling. An average estimation depth to the basement in the study area of about 2.22 km was determined using spectral analysis. Qualitative analysis shows the basement-high pattern, sub-basin, and structure lineament patterns. The 2D model shows three layers consisting of the upper sedimentary layer of Tertiary-Neogene and the middle layer of Tertiary-Paleogene sediment with a density value of 2.3 gr/cc and 2.5 gr/cc, respectively. The lower layer has the highest density of 2.67 gr/cc, assumed as a granitic basement. The results of the Second Vertical Derivative (SVD) analysis on the residual anomaly cross-sectional paths indicate the presence of thrust and normal faults which can be used to assist the interpretation of fault structures in subsurface geological models. Gravity analysis of the offshore North Central Java sedimentary basin indicates the occurrence of sub-basins and geological structure patterns that considered as a potential zone for the development of the petroleum system in this area.","PeriodicalId":31610,"journal":{"name":"Bulletin of the Marine Geology","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45388366","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-01-04DOI: 10.32693/bomg.37.2.2022.783
R. S. Jatiningrum, Anggun Mutika, L. Gustiantini, N. Y. Gerhaneu, G. Latuputty, Agustina Rosi Divina
Putri Island is the outermost island bordering Singapore, located north of Batam City, Riau Archipelago Province. A total of 29 sediment samples were collected from the seafloor off Putri Island for foraminiferal study. The purpose of this study is to determine their abundance and distribution related to previous data of environmental conditions. For this study, we analysed quantitative analysis of benthic foraminifera including its abundance, diversity, dominance, and evenness indices. The results denoted that benthic foraminifera was composed of 62 species that belonged to 31 genera. The diversity index was categorized as a moderate to high diversity index (1.85-3.12), with a low to high evenness index (0.37 – 0.78), and a low dominance index (0.05-0.24). This indicates that in general the waters of Putri Island are considered to have a fairly good environment and are quite stable for foraminiferal growth. A slight environmental stability degradation occurred in the north eastern part of the study area which demonstrates high levels of pollutants in the waters. This situation influent the benthic assemblages which are indicated by lowering index diversity at that location.
{"title":"DISTRIBUTION OF BENTHIC FORAMINIFERA IN THE WATERS FROM OFF PUTRI ISLAND, NORTHERN BATAM, RIAU ARCHIPELAGO","authors":"R. S. Jatiningrum, Anggun Mutika, L. Gustiantini, N. Y. Gerhaneu, G. Latuputty, Agustina Rosi Divina","doi":"10.32693/bomg.37.2.2022.783","DOIUrl":"https://doi.org/10.32693/bomg.37.2.2022.783","url":null,"abstract":"Putri Island is the outermost island bordering Singapore, located north of Batam City, Riau Archipelago Province. A total of 29 sediment samples were collected from the seafloor off Putri Island for foraminiferal study. The purpose of this study is to determine their abundance and distribution related to previous data of environmental conditions. For this study, we analysed quantitative analysis of benthic foraminifera including its abundance, diversity, dominance, and evenness indices. The results denoted that benthic foraminifera was composed of 62 species that belonged to 31 genera. The diversity index was categorized as a moderate to high diversity index (1.85-3.12), with a low to high evenness index (0.37 – 0.78), and a low dominance index (0.05-0.24). This indicates that in general the waters of Putri Island are considered to have a fairly good environment and are quite stable for foraminiferal growth. A slight environmental stability degradation occurred in the north eastern part of the study area which demonstrates high levels of pollutants in the waters. This situation influent the benthic assemblages which are indicated by lowering index diversity at that location.","PeriodicalId":31610,"journal":{"name":"Bulletin of the Marine Geology","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-01-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45398217","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-01-01DOI: 10.32693/bomg.37.2.2022.774
Abdul Motalib Angkotasan, D. Bengen, I. Nurjaya, N. Zamani, N. M. Natih, F. Novico
The geomorphology of small islands in the eastern and western parts of Halmahera Island encompasses diversities of geological processes, island forms and types, and topography. The typology of the small islands to the west of Halmahera Island is volcanic and are categorized as hilly islands. To the east, there are coral islands classified as flat islands with smaller area contrast to volcanic ones. This study aims to analyze the land mass elevation of the small islands and the sub-bottom profiles in the eastern and western Halmahera waters. Island elevation data was obtained from Sentinel-2B imagery, whereas seafloor topographic data was acquired from direct field measurements using a GPS sounder. First, the image data underwent atmospheric, radiometric, and sunlight corrections, while the actual depth was estimated through bathymetry correction using tidal data. Then, QGIS version 3.16.6 and ArcGIS version 10.8 were used to analyze the data. The results show that the slope degree of volcanic islands is higher and their seafloor topography is steeper than that of coral islands. The slope degree of Ternate, Maitara, Tidore, and Hiri Islands, abbreviated as Termadoreh, is more than 30o with elevation of more than 100 meters, characterizing hilly islands. While there is only Pakal Island in Buli Bay that has a slope of 33o and the highest elevation of only 100 meters, it is nevertheless considered a flat island. Significantly, the different typologies indicate different morphogenesis and sub-bottom topography; i.e., volcanic islands have higher slope degrees and steeper seafloor profiles compared to coral islands.
{"title":"GEOMORPHOLOGY OF SMALL ISLANDS AND ITS SEAFLOOR PROFILES IN THE EASTERN AND WESTERN HALMAHERA WATERS","authors":"Abdul Motalib Angkotasan, D. Bengen, I. Nurjaya, N. Zamani, N. M. Natih, F. Novico","doi":"10.32693/bomg.37.2.2022.774","DOIUrl":"https://doi.org/10.32693/bomg.37.2.2022.774","url":null,"abstract":"The geomorphology of small islands in the eastern and western parts of Halmahera Island encompasses diversities of geological processes, island forms and types, and topography. The typology of the small islands to the west of Halmahera Island is volcanic and are categorized as hilly islands. To the east, there are coral islands classified as flat islands with smaller area contrast to volcanic ones. This study aims to analyze the land mass elevation of the small islands and the sub-bottom profiles in the eastern and western Halmahera waters. Island elevation data was obtained from Sentinel-2B imagery, whereas seafloor topographic data was acquired from direct field measurements using a GPS sounder. First, the image data underwent atmospheric, radiometric, and sunlight corrections, while the actual depth was estimated through bathymetry correction using tidal data. Then, QGIS version 3.16.6 and ArcGIS version 10.8 were used to analyze the data. The results show that the slope degree of volcanic islands is higher and their seafloor topography is steeper than that of coral islands. The slope degree of Ternate, Maitara, Tidore, and Hiri Islands, abbreviated as Termadoreh, is more than 30o with elevation of more than 100 meters, characterizing hilly islands. While there is only Pakal Island in Buli Bay that has a slope of 33o and the highest elevation of only 100 meters, it is nevertheless considered a flat island. Significantly, the different typologies indicate different morphogenesis and sub-bottom topography; i.e., volcanic islands have higher slope degrees and steeper seafloor profiles compared to coral islands.","PeriodicalId":31610,"journal":{"name":"Bulletin of the Marine Geology","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49022776","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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