Pub Date : 2020-06-02DOI: 10.32693/bomg.35.1.2020.672
S. Zulaikah, R. Pujiastuti, G. Afrillah
Weathering is a geological phenomenon that is often an important considered because of its destructive properties, mainly in subsurface. Many parameters are used to measure the presence of weathering indications. This study focuses on testing of magnetic susceptibility (c), compound oxide content and Fe3O4/Fe2O3 ratio that have been selected as an indicators of weathering process. This study explains in detail the quantitative analysis of weathering based on these parameters in basaltic andesite rocks found in coastal atmospheric areas. The results obtained for weathered rocks, magnetic susceptibility, compound oxide content such as CaO and the Fe3O4/Fe2O3 ratio has decreased significantly. In the coastal atmosphere, the weathering of basaltic andesite rocks also marked by the distribution of magnetic minerals which tend to be in the domain of pseudo single domain (PSD) or single domain (SD). Thus it can be concluded that both of low frequency magnetic susceptibility (clf), CaO and Fe2O3 content and also the Fe3O4/Fe2O3 ratio can be used as weathering level indicators.
{"title":"Detecting Coastal Atmosphere Weathering Process on Andesite Rock Using Magnetic Susceptibility and Fe3O4/Fe2O3 Ratio","authors":"S. Zulaikah, R. Pujiastuti, G. Afrillah","doi":"10.32693/bomg.35.1.2020.672","DOIUrl":"https://doi.org/10.32693/bomg.35.1.2020.672","url":null,"abstract":"Weathering is a geological phenomenon that is often an important considered because of its destructive properties, mainly in subsurface. Many parameters are used to measure the presence of weathering indications. This study focuses on testing of magnetic susceptibility (c), compound oxide content and Fe3O4/Fe2O3 ratio that have been selected as an indicators of weathering process. This study explains in detail the quantitative analysis of weathering based on these parameters in basaltic andesite rocks found in coastal atmospheric areas. The results obtained for weathered rocks, magnetic susceptibility, compound oxide content such as CaO and the Fe3O4/Fe2O3 ratio has decreased significantly. In the coastal atmosphere, the weathering of basaltic andesite rocks also marked by the distribution of magnetic minerals which tend to be in the domain of pseudo single domain (PSD) or single domain (SD). Thus it can be concluded that both of low frequency magnetic susceptibility (clf), CaO and Fe2O3 content and also the Fe3O4/Fe2O3 ratio can be used as weathering level indicators.","PeriodicalId":31610,"journal":{"name":"Bulletin of the Marine Geology","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45223756","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 : 2020-06-02DOI: 10.32693/bomg.35.1.2020.659
Popy Dwi Indriyani, A. Harja, T. B. Nainggolan
Berau Basin is assessed to have same potential in clastic sediments with Mesozoic and Paleozoic ages, where reservoirs and source rocks are similar to productive areas of hydrocarbons in Northwest Shield Australia. This study aims to identify the hydrocarbon prospect zones and potential rocks zones using petrophysical parameters, such as shale volume, porosity, water saturation and permeability. Petrophysical analysis of reservoir and source rock are carried out on three wells located in the Berau Basin, namely DI-1, DI-2 and DI-3 in Kembelangan and Tipuma Formation. Qualitative analysis shows that there are 4 reservoir rock zones and 4 source rock zones from thorough analysis of these three wells. Based on quantitative analysis of DI-1 well, it has an average shale volume (Vsh) 9.253%, effective porosity (PHIE) 20.68%, water saturation (Sw) 93.3% and permeability (k) 55.69 mD. DI-2 well’s average shale volume, effective porosity, water saturation and permeability values are 29.16%, 2.97%, 67.9% and 0.05 mD, respectively. In DI-3 well, average shale volume, effective porosity, water saturation and permeability values are 6.205%, 19.36%, 80.2% and 242.05 mD, respectively. From the reservoir zone of these three wells in Kembelangan Formation, there are no show any hydrocarbon prospect.
{"title":"Petrophysical Analysis to Determine Reservoir and Source Rocks in Berau Basin, West Papua Waters","authors":"Popy Dwi Indriyani, A. Harja, T. B. Nainggolan","doi":"10.32693/bomg.35.1.2020.659","DOIUrl":"https://doi.org/10.32693/bomg.35.1.2020.659","url":null,"abstract":"Berau Basin is assessed to have same potential in clastic sediments with Mesozoic and Paleozoic ages, where reservoirs and source rocks are similar to productive areas of hydrocarbons in Northwest Shield Australia. This study aims to identify the hydrocarbon prospect zones and potential rocks zones using petrophysical parameters, such as shale volume, porosity, water saturation and permeability. Petrophysical analysis of reservoir and source rock are carried out on three wells located in the Berau Basin, namely DI-1, DI-2 and DI-3 in Kembelangan and Tipuma Formation. Qualitative analysis shows that there are 4 reservoir rock zones and 4 source rock zones from thorough analysis of these three wells. Based on quantitative analysis of DI-1 well, it has an average shale volume (Vsh) 9.253%, effective porosity (PHIE) 20.68%, water saturation (Sw) 93.3% and permeability (k) 55.69 mD. DI-2 well’s average shale volume, effective porosity, water saturation and permeability values are 29.16%, 2.97%, 67.9% and 0.05 mD, respectively. In DI-3 well, average shale volume, effective porosity, water saturation and permeability values are 6.205%, 19.36%, 80.2% and 242.05 mD, respectively. From the reservoir zone of these three wells in Kembelangan Formation, there are no show any hydrocarbon prospect.","PeriodicalId":31610,"journal":{"name":"Bulletin of the Marine Geology","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44839233","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 : 2020-06-02DOI: 10.32693/bomg.35.1.2020.598
Hersenanto Catur Widiatmoko, Eddy Mirnanda, H. Kurnio
Fragments of ultramafic, metamorphic, basalt and serpentine compose coastal sediments. These fragments derived from outcrops in hinterland as well as the coast. Existence of greywacke sandstone through microscopic observation in coastal sediments indicate deep sea derivation. Marine sediments also show almost the same composition with coastal sediments.Rock fragment abundances of ultramafic (10-47%), serpentine (12-24%) and metamorphic (3-12%) in stream and coastal sediments which have direct relation with the presence of nickel metal in the research area were resulted from petrographic analyses. While mineralographic analyses of heavy mineral concentrate from wooden pan show the existence of ferro nickel (Fe-Ni) and nickeline (Ni-As) in coastal and stream sediments. XRF analyses show nickel contents in seabed sediments 0.0140 to 0.793 %, chromite 0.0179 to 0.1128% and iron 1.2 to 6.85%. Coastal water nickel distribution is controlled by local trapped waves in Buli Bay that excite by equatorial Pacific Ocean waves propagate westward. Nickel occurrences in marine sediments would be an interesting further research.
{"title":"Nickel in Buli Coastal Area, East Halmahera","authors":"Hersenanto Catur Widiatmoko, Eddy Mirnanda, H. Kurnio","doi":"10.32693/bomg.35.1.2020.598","DOIUrl":"https://doi.org/10.32693/bomg.35.1.2020.598","url":null,"abstract":"Fragments of ultramafic, metamorphic, basalt and serpentine compose coastal sediments. These fragments derived from outcrops in hinterland as well as the coast. Existence of greywacke sandstone through microscopic observation in coastal sediments indicate deep sea derivation. Marine sediments also show almost the same composition with coastal sediments.Rock fragment abundances of ultramafic (10-47%), serpentine (12-24%) and metamorphic (3-12%) in stream and coastal sediments which have direct relation with the presence of nickel metal in the research area were resulted from petrographic analyses. While mineralographic analyses of heavy mineral concentrate from wooden pan show the existence of ferro nickel (Fe-Ni) and nickeline (Ni-As) in coastal and stream sediments. XRF analyses show nickel contents in seabed sediments 0.0140 to 0.793 %, chromite 0.0179 to 0.1128% and iron 1.2 to 6.85%. Coastal water nickel distribution is controlled by local trapped waves in Buli Bay that excite by equatorial Pacific Ocean waves propagate westward. Nickel occurrences in marine sediments would be an interesting further research.","PeriodicalId":31610,"journal":{"name":"Bulletin of the Marine Geology","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43760623","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 : 2019-12-10DOI: 10.32693/bomg.34.2.2019.595
P. Raharjo, M. Saputra, Delyuzar Illahude, P. H. Wijaya
Delta Topang, located in Topang Island, Riau Province is known to have the potential of biogenic gas. This research was conducted to identify the Quaternary sediment and the existence of biogenic gas reservoar. In this research has been conducted 75 points of surface geoelectrical measurements (38 points in Parit Jawa and 37 points in Parit Bintang) and 2 points of core drilling (BH-1 in Parit Jawa and BH-2 in Parit Bintang). Total Organic Carbon was also carried out on 10 samples (5 samples from each drilling core). Based on resistivity value of geoelectrical measurements from all points, in general are determined 2 sediment types, very fine sediment (silt and clay) and fine sand. We discussed in detail only point 11 representing Parit Jawa region and point 39 representing Parit Bintang Village. Both in point 11 and point 39, very fine sediment was identified from the surface down to 59 m and 58.5 m respectively, mostly dominated by hydrous clay. Below these, very fine sediment is identified as fine sand. Core drilling BH-1 and BH-2 (40 m length each) composed of thick layer of hydrous clay from the core surface down to bottom part, intercalated with thin layers of silt and fine sand. We considered fine sand found at depths between 24 to > 90 m (from all geoelectrical measurement points) as the closure of biogenic gas. At Parit Jawa biogenic gas closures are found at 2 locations, which are in south west and north east measurement area. At Parit Bintang biogenic gas closures are found at 3 location which are one in south and two in north measurement area. Total organic carbon analyzed from BH-1 indicate the highest percentage at 26-27 m depth with percentage 71.6%. From BH-2 the highest value is indicated at 33-34 m depth with percentage 78.0%. From all this information it is known that the formation of biogenic gas from the abundance of TOC is in the layers of hydrous clay and clay where is in an anaerobic sulfate-reduction environment.
{"title":"Identification of Quaternary Sediments and the Existence of Biogenic Gas Sources in the Topang Delta, Meranti, Riau","authors":"P. Raharjo, M. Saputra, Delyuzar Illahude, P. H. Wijaya","doi":"10.32693/bomg.34.2.2019.595","DOIUrl":"https://doi.org/10.32693/bomg.34.2.2019.595","url":null,"abstract":"Delta Topang, located in Topang Island, Riau Province is known to have the potential of biogenic gas. This research was conducted to identify the Quaternary sediment and the existence of biogenic gas reservoar. In this research has been conducted 75 points of surface geoelectrical measurements (38 points in Parit Jawa and 37 points in Parit Bintang) and 2 points of core drilling (BH-1 in Parit Jawa and BH-2 in Parit Bintang). Total Organic Carbon was also carried out on 10 samples (5 samples from each drilling core). Based on resistivity value of geoelectrical measurements from all points, in general are determined 2 sediment types, very fine sediment (silt and clay) and fine sand. We discussed in detail only point 11 representing Parit Jawa region and point 39 representing Parit Bintang Village. Both in point 11 and point 39, very fine sediment was identified from the surface down to 59 m and 58.5 m respectively, mostly dominated by hydrous clay. Below these, very fine sediment is identified as fine sand. Core drilling BH-1 and BH-2 (40 m length each) composed of thick layer of hydrous clay from the core surface down to bottom part, intercalated with thin layers of silt and fine sand. We considered fine sand found at depths between 24 to > 90 m (from all geoelectrical measurement points) as the closure of biogenic gas. At Parit Jawa biogenic gas closures are found at 2 locations, which are in south west and north east measurement area. At Parit Bintang biogenic gas closures are found at 3 location which are one in south and two in north measurement area. Total organic carbon analyzed from BH-1 indicate the highest percentage at 26-27 m depth with percentage 71.6%. From BH-2 the highest value is indicated at 33-34 m depth with percentage 78.0%. From all this information it is known that the formation of biogenic gas from the abundance of TOC is in the layers of hydrous clay and clay where is in an anaerobic sulfate-reduction environment.","PeriodicalId":31610,"journal":{"name":"Bulletin of the Marine Geology","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49362492","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 : 2019-05-24DOI: 10.32693/bomg.34.1.2019.590
Subarsyah Subarsyah, L. Arifin
Acoustic waves propagate through a medium meet the Snell’s Law, its energy is reflected and some are scattered back at certain angle. The Side Scan Sonar (SSS) methods use this principle to identify seabed character. The intensity of the backscatter greatly depends on the morphology and sediments texture or rocks distributed on seabed.The intensity of backscatter waves is a representation of the morphology, sediments texture, and types of rock that distributed on the seabed, therefore it is possible to estimate sedimentary texture and identify the presence of rocks or coral reefs based on this information. In this publication authors estimate sediments texture, rocks or coral reefs based on backscatter intensity through the image processing on the Side Scan Sonar (SSS) image. Intensity will be converted into pixel values on the image with range value 1-255 (gray scale image) and entropy values which are statistical measures of randomness. Entropy value is maximum when most of pixel value image is in the middle of the colour spectrum range (between very dark to very bright), in contrast, it is minimum when pixel value is in the spectrum of very dark or very bright. Based on both parameters, classification is conducted. The classification is carried out on the SSS image at Bontang and Batam that have very different seabed characters.The classification results using an image processing shows that the distribution of sediment textures consist of 4 (four) classes for either Batam or Bontang. In the Bontang area, very fine sediments were identified which are associated with low value of both intensity and entropy - dark zones in gray scale images, and coarse sediments associated with high value of both intensity and entropy - bright zone in the gray scale image. Similar characteristic is observed in Batam area, which are identified fine sediment (associated to low intensity) - coarse sediments (high intensity). In contrast to Bontang, in Batam the entropy exhibit the opposite value, high value are correlated to fine sediment and vice versa. This might be due to the presence of rocks and sedimentary structures.Keywords: Side Scan Sonar, Intensity, Backscatter and entropy.Gelombang akustik sebagian besar energinya dipantulkan memenuhi prinsip snellius dan sebagian kecil dihamburkan balik dengan sudut. Metode Side Scan Sonar (SSS) memanfaatkan prinsip hambur-balik gelombang untuk mengidentifikasi permukaan dasar laut. Intensitas gelombang dari karakter hambur-balik akan sangat tergantung morfologi dan tekstur sedimen atau batuan dari permukaan dasar lautnya. Intensitas gelombang hambur-balik merupakan representasi dari morfologi, tekstur sedimen, dan jenis batuan yang tersebar di permukaan dasar laut, sehingga sangat memungkinkan untuk melakukan estimasi tekstur sedimen dan identifikasi keberadaan batuan maupun terumbu karang berdasarkan informasi tersebut. Pada publikasi ini akan dilakukan estimasi tekstur sedimen atau batuan berdasarkan intensitas hambu
{"title":"Seabed Characterization through Image Processing of Side Scan Sonar Case Study: Bontang and Batam","authors":"Subarsyah Subarsyah, L. Arifin","doi":"10.32693/bomg.34.1.2019.590","DOIUrl":"https://doi.org/10.32693/bomg.34.1.2019.590","url":null,"abstract":"Acoustic waves propagate through a medium meet the Snell’s Law, its energy is reflected and some are scattered back at certain angle. The Side Scan Sonar (SSS) methods use this principle to identify seabed character. The intensity of the backscatter greatly depends on the morphology and sediments texture or rocks distributed on seabed.The intensity of backscatter waves is a representation of the morphology, sediments texture, and types of rock that distributed on the seabed, therefore it is possible to estimate sedimentary texture and identify the presence of rocks or coral reefs based on this information. In this publication authors estimate sediments texture, rocks or coral reefs based on backscatter intensity through the image processing on the Side Scan Sonar (SSS) image. Intensity will be converted into pixel values on the image with range value 1-255 (gray scale image) and entropy values which are statistical measures of randomness. Entropy value is maximum when most of pixel value image is in the middle of the colour spectrum range (between very dark to very bright), in contrast, it is minimum when pixel value is in the spectrum of very dark or very bright. Based on both parameters, classification is conducted. The classification is carried out on the SSS image at Bontang and Batam that have very different seabed characters.The classification results using an image processing shows that the distribution of sediment textures consist of 4 (four) classes for either Batam or Bontang. In the Bontang area, very fine sediments were identified which are associated with low value of both intensity and entropy - dark zones in gray scale images, and coarse sediments associated with high value of both intensity and entropy - bright zone in the gray scale image. Similar characteristic is observed in Batam area, which are identified fine sediment (associated to low intensity) - coarse sediments (high intensity). In contrast to Bontang, in Batam the entropy exhibit the opposite value, high value are correlated to fine sediment and vice versa. This might be due to the presence of rocks and sedimentary structures.Keywords: Side Scan Sonar, Intensity, Backscatter and entropy.Gelombang akustik sebagian besar energinya dipantulkan memenuhi prinsip snellius dan sebagian kecil dihamburkan balik dengan sudut. Metode Side Scan Sonar (SSS) memanfaatkan prinsip hambur-balik gelombang untuk mengidentifikasi permukaan dasar laut. Intensitas gelombang dari karakter hambur-balik akan sangat tergantung morfologi dan tekstur sedimen atau batuan dari permukaan dasar lautnya. Intensitas gelombang hambur-balik merupakan representasi dari morfologi, tekstur sedimen, dan jenis batuan yang tersebar di permukaan dasar laut, sehingga sangat memungkinkan untuk melakukan estimasi tekstur sedimen dan identifikasi keberadaan batuan maupun terumbu karang berdasarkan informasi tersebut. Pada publikasi ini akan dilakukan estimasi tekstur sedimen atau batuan berdasarkan intensitas hambu","PeriodicalId":31610,"journal":{"name":"Bulletin of the Marine Geology","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47653556","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 : 2019-05-24DOI: 10.32693/bomg.34.1.2019.570
Lestari Lestari, F. Budiyanto, C. Y. Manullang
Five metals in sediment samples at seven sites from the Ambon Bay were analyzed with BCR sequential extraction procedure to determine chemical fractionation of metals and to assess bioavailability of metals with Risk Assessment Code (RAC). The result showed that the percentages of cadmium (100%), lead (82.6-97.08%) and zinc (41.68-76.33%) were mostly accumulated in the non-residual (F1+F2+F3) fraction of the total concentrations. While the copper percentages (44.74-78.91%) and nickel (59.71-74.16%) were mostly accumulated in residual (F4) fraction of the total concentrations. The Risk Assessment Code (RAC) reveals that cadmium, copper, nickel and zinc at locations exist in acid soluble (exchangeable) fraction and therefore, they are in low until very high risk category meanwhile there is no Pb at locations exist in acid soluble (exchangeable) fraction.
{"title":"A First Record of Metal Fractionation in Coastal Sediment from Ambon Bay, Moluccas, Indonesia","authors":"Lestari Lestari, F. Budiyanto, C. Y. Manullang","doi":"10.32693/bomg.34.1.2019.570","DOIUrl":"https://doi.org/10.32693/bomg.34.1.2019.570","url":null,"abstract":"Five metals in sediment samples at seven sites from the Ambon Bay were analyzed with BCR sequential extraction procedure to determine chemical fractionation of metals and to assess bioavailability of metals with Risk Assessment Code (RAC). The result showed that the percentages of cadmium (100%), lead (82.6-97.08%) and zinc (41.68-76.33%) were mostly accumulated in the non-residual (F1+F2+F3) fraction of the total concentrations. While the copper percentages (44.74-78.91%) and nickel (59.71-74.16%) were mostly accumulated in residual (F4) fraction of the total concentrations. The Risk Assessment Code (RAC) reveals that cadmium, copper, nickel and zinc at locations exist in acid soluble (exchangeable) fraction and therefore, they are in low until very high risk category meanwhile there is no Pb at locations exist in acid soluble (exchangeable) fraction.","PeriodicalId":31610,"journal":{"name":"Bulletin of the Marine Geology","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49011206","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 : 2019-05-24DOI: 10.32693/bomg.34.1.2019.621
I. Setiadi, B. Setyanta, T. B. Nainggolan, J. Widodo
East Java basin is a very large sedimentary basin and has been proven produce hydrocarbons, this basin consists of several different sub-basins, one of the sub-basin is in the Madura Strait and surrounding areas. Gravity is one of the geophysical methods that can be used to determine geological subsurface configurations and delineate sedimentary sub-basin based on density parameter. The purposes of this study are to delineate sedimentary sub-basins, estimate the thickness of sedimentary rock, interpret subsurface geological model and identify geological structures in the Madura Strait and surrounding areas. Data analysis which used in this paper are spectral analysis, spectral decomposition filter and 2D forward modeling. The results of the spectral analysis show that the thickness of sedimentary rock is about 3.15 Km. Spectral decomposition is performed at four different wave numbers cut off, namely (0.36, 0.18, 0.07 and 0.04), each showing anomaly patterns at depth (1 Km, 2 Km, 3 Km and 4 Km). The sub-basins that can be delineated from the gravity data analysis are 10 sedimentary sub-basins, while the structural patterns identified are basement high, graben and fault. 2D modeling results indicate that the basement is a continental crust with a mass density value of 2.7 gr/cc. Sedimentary rock from modeling result consecutively from the bottom to up, the first is Paleogene sedimentary rock with mass density value of 2.4 gr/cc and above this layer is Neogene sedimentary rocks with mass density values of 2.25 gr/cc. The results of the subsurface geological modeling analysis show that based on the graben pattern and the basement high of the East Java basin in the Madura Strait and surrounding areas there are many structural patterns that support the development of petroleum systems like at the western part of the East Java basin that have already produced hydrocarbon.Keywords : Gravity, spectral analysis, spectral decomposition filter, 2D Modeling, East java basin Cekungan Jawa Timur merupakan cekungan sedimen yang sangat besar dan telah terbukti memiliki kandungan minyak dan gas bumi. Cekungan ini terdiri atas beberapa sub-cekungan yang berbeda-beda, salah satunya adalah sub-cekungan yang ada pada wilayah selat Madura dan sekitarnya. Gayaberat merupakan salah satu metoda geofisika yang dapat digunakan untuk mengetahui konfigurasi bawah permukaan serta mendelineasi sub-cekungan sedimen berdasarkan parameter rapat massa (densitas). Tujuan dari penelitian ini adalah untuk mendelineasi sub-cekungan sedimen, memperkirakan ketebalan sedimen, menginterpretasi geologi bawah permukaan serta mengidentifikasi struktur yang ada pada wilayah selat madura dan sekitarnya. Analisis data yang digunakan yaitu analisis spektral, filter spektral dekomposisi serta pemodelan maju (forward modeling) 2D. Hasil analisis spektral menunjukaan bahwa tebal batuan sedimen rata-rata adalah sekitar 3.15 Km. Spektral dekomposisi dilakukan pada empat bilangan gelombang cuttoff yan
东爪哇盆地是一个非常大的沉积盆地，已被证实具有油气生产能力，该盆地由几个不同的子盆地组成，其中一个子盆地位于马杜拉海峡及其周边地区。重力是一种基于密度参数确定地质地下构造和圈定沉积次盆地的地球物理方法。研究的目的是在马杜拉海峡及周边地区进行沉积次盆地圈定、沉积岩厚度估算、地下地质模型解释和地质构造识别。本文使用的数据分析方法包括光谱分析、光谱分解滤波和二维正演建模。光谱分析结果表明，沉积岩厚度约为3.15 Km。在(0.36、0.18、0.07和0.04)4个不同的波数截断点进行频谱分解，每个波数分别显示深度(1 Km、2 Km、3 Km和4 Km)的异常模式。重力资料分析圈定了10个沉积子盆地，确定了基底隆起、地堑和断裂等构造模式。二维模拟结果表明，基底为大陆地壳，质量密度为2.7 gr/cc。从建模结果来看，沉积岩从下向上依次为:第一层为古近系沉积岩，质量密度值为2.4 gr/cc，其上一层为新近系沉积岩，质量密度值为2.25 gr/cc。地下地质模拟分析结果表明，在马都拉海峡及周边地区东爪哇盆地地堑格局和基底隆起的基础上，存在许多支持含油气系统发育的构造格局，如东爪哇盆地西部已经产烃的构造格局。关键词:重力，光谱分析，光谱分解滤波器，二维建模，东爪哇盆地，切昆干，爪哇，木木尔，merupakan，切昆干，沉积，阳sangat besar, dan telah, terbukti, memiliki, kandungan, minyak, dan gas bumi这句话的意思是:“我是说，我是说，我是说，我是说，我是说，我是说，我是说，我是说，我是说，我是说，我是说，我是说，我是说，我是说，我是说，我是说，我是说，我是说。”Gayaberat merupakan salah satu mettoda geofisika yang dapat digunakan untuk mengetahui konfigasi bawah permukaan serta mendelineasi sub- kungan sedimen berdasarkan参数rapat massa (density)。Tujuan dari penelitian ini adalah untuk mendelineasi subcekungan sedimen, memperkirakan ketebalan sedimen, menginterpretasi geologi bawah permukaan serta mengidentifikasi strukturr yang ada ada wilayah selat madura dan sekitarya。分析数据杨迪古纳坎亚图分析光谱，滤波光谱分解，serta pemodelan maju(正演模拟)2D。Hasil分析光谱menunjukaan bahwa tebal batuan沉积物rata-rata adalah sekitar 3.15 Km。光谱dekomposisi dilakukan pada empat bilangan gelombang cut off yang berbeda beda yitu (0.36, 0.18, 0.07, 0.04) yang masing-masing menunjukkan pola anomali pada kedalaman (1 Km, 2 Km, 3 Km, 4 Km)。10个切昆干下沉积、切当坎坡坡构造、切当坎坡坡构造、切当坎断陷、切当坎断陷、切当坎断陷。Hasil pemodelan 2D menunjukkan bahwa batuan dasar adalah berupa kerak kontinen dengan nilai rapat massa 2.7 gr/cc。巴团沉积系hail - permodelan - secara - bertura - turut - dari - bawah - ke - as - yang perama - yitu巴团沉积系yang berum古近系dengan - nilai - rapat mass 2.4 g /cc, didiatasnya - adalah巴团沉积系yang mempunyai - nilai rapat mass新近系yang mempunyai - nilai rapat mass 2.25 g /cc。Hasil分析模型bawah permukaan menunjukkan bahwa berdasarkan pola地陷带dantinggian cekungan爪哇帖木儿段selat Madura dansekitarya cuup banyak terdapat pola构造带yang mendukung berkembangnya石油系统seperti pada wilayah sebelah barat cekungan爪哇帖木儿yang sudah berproduksi油气。Kata Kunci: Gayaberat，光谱分析，滤波光谱分解，pemodelan 2D, Cekungan java Timur
{"title":"Delineation of Sedimentary Subbasin and Subsurface Interpretation East Java Basin in the Madura Strait and Surrounding Area Based on Gravity Data Analysis","authors":"I. Setiadi, B. Setyanta, T. B. Nainggolan, J. Widodo","doi":"10.32693/bomg.34.1.2019.621","DOIUrl":"https://doi.org/10.32693/bomg.34.1.2019.621","url":null,"abstract":"East Java basin is a very large sedimentary basin and has been proven produce hydrocarbons, this basin consists of several different sub-basins, one of the sub-basin is in the Madura Strait and surrounding areas. Gravity is one of the geophysical methods that can be used to determine geological subsurface configurations and delineate sedimentary sub-basin based on density parameter. The purposes of this study are to delineate sedimentary sub-basins, estimate the thickness of sedimentary rock, interpret subsurface geological model and identify geological structures in the Madura Strait and surrounding areas. Data analysis which used in this paper are spectral analysis, spectral decomposition filter and 2D forward modeling. The results of the spectral analysis show that the thickness of sedimentary rock is about 3.15 Km. Spectral decomposition is performed at four different wave numbers cut off, namely (0.36, 0.18, 0.07 and 0.04), each showing anomaly patterns at depth (1 Km, 2 Km, 3 Km and 4 Km). The sub-basins that can be delineated from the gravity data analysis are 10 sedimentary sub-basins, while the structural patterns identified are basement high, graben and fault. 2D modeling results indicate that the basement is a continental crust with a mass density value of 2.7 gr/cc. Sedimentary rock from modeling result consecutively from the bottom to up, the first is Paleogene sedimentary rock with mass density value of 2.4 gr/cc and above this layer is Neogene sedimentary rocks with mass density values of 2.25 gr/cc. The results of the subsurface geological modeling analysis show that based on the graben pattern and the basement high of the East Java basin in the Madura Strait and surrounding areas there are many structural patterns that support the development of petroleum systems like at the western part of the East Java basin that have already produced hydrocarbon.Keywords : Gravity, spectral analysis, spectral decomposition filter, 2D Modeling, East java basin Cekungan Jawa Timur merupakan cekungan sedimen yang sangat besar dan telah terbukti memiliki kandungan minyak dan gas bumi. Cekungan ini terdiri atas beberapa sub-cekungan yang berbeda-beda, salah satunya adalah sub-cekungan yang ada pada wilayah selat Madura dan sekitarnya. Gayaberat merupakan salah satu metoda geofisika yang dapat digunakan untuk mengetahui konfigurasi bawah permukaan serta mendelineasi sub-cekungan sedimen berdasarkan parameter rapat massa (densitas). Tujuan dari penelitian ini adalah untuk mendelineasi sub-cekungan sedimen, memperkirakan ketebalan sedimen, menginterpretasi geologi bawah permukaan serta mengidentifikasi struktur yang ada pada wilayah selat madura dan sekitarnya. Analisis data yang digunakan yaitu analisis spektral, filter spektral dekomposisi serta pemodelan maju (forward modeling) 2D. Hasil analisis spektral menunjukaan bahwa tebal batuan sedimen rata-rata adalah sekitar 3.15 Km. Spektral dekomposisi dilakukan pada empat bilangan gelombang cuttoff yan","PeriodicalId":31610,"journal":{"name":"Bulletin of the Marine Geology","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42432738","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 : 2019-05-24DOI: 10.32693/bomg.34.1.2019.637
Fathkhurozak Yunanda Rifai, T. B. Nainggolan, H. Manik
Seismic method is one of the most frequently applied geophysical methods in the process of oil and gas exploration. This research is conducted in Nias Waters, North Sumatra using one line 2D post-stack time migration seismic section and two wells data. Reservoir characterization is carried out to obtain physical parameters of rocks affected by fluid and rock lithology. Seismic inversion is used as a technique to create acoustic impedance distribution using seismic data as input and well data as control. As final product, multi-attribute analysis is applied to integrate of inversion results with seismic data to determine the lateral distribution of other parameters contained in well data. In this research, multi-attribute analysis is used to determine the distribution of NPHI as a validation of hydrocarbon source rocks. In that area, there is a gas hydrocarbon prospect in limestone lithology in depth around 1450 ms. Based on the results of sensitivity analysis, cross-plot between acoustic impedance and NPHI are sensitive in separating rock lithology, the target rock in the form of limestone has physical characteristics in the form of acoustic impedance values in the range of 20,000-49,000 ((ft/s)*(g/cc)) and NPHI values in the range of 5-35 %. While the results of the cross-plot between the acoustic impedance and resistivity are able to separate fluid-containing rocks with resistivity values in the range about 18-30 ohmm. The result of acoustic impedance inversion using the model based method shows the potential for hydrocarbons in the well FYR-1 with acoustic impedance in the range 21,469-22,881 ((ft/s)*(gr/cc)).
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Pub Date : 2019-05-24DOI: 10.32693/bomg.34.1.2019.622
T. B. Nainggolan, Said Muhammad Rasidin, I. Setiadi
Multiple often and always appear in marine seismic data due to very high acoustic impedance contrasts. These events have undergone more than one reflection. This causes the signal to arrive back at the receiver at an erroneous time, which, in turn, causes false results and can result in data misinterpretation. Several types of multiple suppression have been studied in literature. Methods that attenuate multiples can be classified into three broad categories: deconvolution methods; filtering methods and wavefield prediction subtraction methods. The study area is situated on Seram Sea in between 131°15’E – 132°45’E and 3°0’S – 4°0’S, Seram Trough which is located beneath Seram Sea at northern part of the Banda-Arc – Australian collision zone and currently the site of contraction between Bird’s Head and Seram. This research uses predictive deconvolution and FK-filter to attenuate short period multiple from their move out, then continued by SRME method to predict multiple that cannot be attenuated from previous method, then followed by Radon transform to attenuate multiple that still left and cannot be attenuated by SRME method. The result of each method then compared to each other to see how well multiple attenuated. Predictive deconvolution and F-K filter could not give satisfactory result especially complex area where multiple in dipping event is not periodic, SRME method successfully attenuate multiple especially in near offset multiple without need subsurface information, while SRME method fails to attenuate long offset multiple, combination of SRME method and Radon transform can give satisfactory result with careful selection of the Radon transform parameters because it can obscure some primary reflectors. Based on geological interpretation, Seram Trough is built by dominant structural style of deposited fold and thrust belt. The deposited fold and thrust belt has a complexly fault geometry from western zone until eastern of seismic line.
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Pub Date : 2019-03-26DOI: 10.32693/bomg.33.2.2018.547
T. Purbonegoro, M. Cordova, R. Puspitasari, D. Hindarti
Jakarta Bay coastal ecosystem is known suffered from water pollution and habitat degradation. Solid and fluid waste from households and several industrial areas flow and ended up in the bay. Ecotoxicological studies are needed to assess the effects of pollutant on marine organism, including phytoplankton as the primary producer. Therefore chemical analysis and toxicity test were performed to investigate the impact of Jakarta Bay Sediments to marine diatoms Chaetoceros gracilis. Heavy metals concentration especially Cu, Pb, Cd, and Hg in the sediments were lower than in previous studies. It could be related to the stricter environmental regulations which started enforced at the end of 1990s. Meanwhile, PAH and pesticide were higher than in previous studies. Increasing activities and maritime traffic in surrounding area of Tanjung Priok Port area and most likely comes from other adjacent harbors (Muara Baru, Muara Angke, and Marina Ancol harbor) and the massive usage of the pesticide compound in the households of the Jakarta City area were suspected to be the reasons. Estuaries area and locations <10 km were identified and predicted would produce harmful effects since the concentration of Zn and Hg in those area exceeded Probable Effects Level (PEL) of Sediment Quality Guidelines (SQG). The growth responses of Chaetoceros gracilis were varied greatly. Most of the sites (24 from 31 sites) showed inhibition effects on the growth of diatoms, ranged from 1.75-35.33 % (17.75±9.59 %) relative to control, with the highest inhibition value was at Cengkareng Drain estuary (M2). The relationship between the concentration of contaminants and the inhibition response could not be clearly explained, however, there is an assumption that low concentrations of some heavy metals were suspected to give adverse effects on diatom’s growth.Keywords: sediment, toxicity, marine diatoms, Chaetoceros gracilis, Jakarta BayEkosistem Teluk Jakarta dikenal mengalami pencemaran air dan degradasi habitat. Limbah cair dan padat berasal dari perumahan dan industri mengalir dan berakhir di teluk tersebut. Kajian ekotoksikologi diperlukan untuk mengetahui pengaruh pencemar terhadap organisme laut termasuk fitoplankton sebagai produsen primer. Analisis kimia dan uji toksisitas dilakukan untuk mengetahui dampak sedimen Teluk Jakarta terhadap diatom laut Chaetoceros gracilis. Konsentrasi logam berat terutama Cu, Pb, Cd, dan Hg dalam sedimen lebih rendah dari penelitian sebelumnya. Hal tersebut berkaitan dengan peraturan lingkungan ketat yang mulai diberlakukan pada akhir 1990-an. Namun demikian, konsentrasi PAH dan pestisida lebih tinggi dari penelitian sebelumnya. Hal tersebut diduga kuat akibat dari peningkatan aktivitas dan lalu lintas maritim di daerah sekitar Pelabuhan Tanjung Priok, juga kemungkinan besar berasal dari pelabuhan lain yang berdekatan (Muara Baru, Muara Angke, dan pelabuhan Marina Ancol) serta akibat penggunaan besar-besaran senyawa pestisida kegiatan rumah tangga di
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