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Karakteristik Sistem Akuifer pada Formasi Endapan Permukaan di Daerah Sei Mati Kota Medan Berdasarkan Metode Geolistrik 2D Mutaqin, Deden Zaenudin; Mardiana, Undang; Alfadli, Muhammad Kurniawan; Mohammad, Febriwan; Yuniardi, Yuyun; Nur, Andi Agus
BERKALA SAINSTEK Vol 8 No 4 (2020)
Publisher : Universitas Jember

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.19184/bst.v8i4.18102

Abstract

Daerah Sei mati memiliki potensi sumber daya air yang baik, dikarenakan daerah yang termasuk Cekungan Air tanah Medan. Penelitian ini bertujuan untuk mengetahui potensi airtanah dengan menggunakan metode geolistrik 2D dengan konfigurasi wenner-schulumberger. Hasil penelitian menunjukan terdapat 2 lapisan akuifer yaitu akuifer dangkal dan dalam. Lapisan akifer dangkal berada pada kedalaman berkisar antara 0 – 50 meter, membentuk pola channel-channel yang menunjukan endapan fluvial dengan nilai tahanan jenis antara 5 Ω.m - 10 Ω.m, dengan litologi pasir lempungan, namun dibeberapa tempat dijumpai channel lempung yang bersifat akuiklud (tidak dapat menyimpan air). Lapisan akuifer dalam muncul pada kedalaman 50 meter hingga 100 meter dengan litologi pasir.
Eocene – Late Miocene Tectonostratigraphy of Bima Field in Northwest Java Basin Natasia, Nanda; Alfadli, Muhammad Kurniawan; Syafri, Ildrem
Journal of Geological Sciences and Applied Geology Vol 2, No 3 (2017): Journal of Geological Sciences and Applied Geology
Publisher : Faculty of Geological Engineering, Universitas Padjadjaran

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24198/gsag.v2i3.15619

Abstract

This study aim to understand the tectonostratigraphy of Bima Field from Basement forming in Eocene to Late Miocene Interval based on seismic observation. Regional structural analysis of the Bima Field and surrounding area was conducted using integration 2D seismic lines and existing wells. The main purpose of the analysis is to describe structural pattern and style in the study area in relation to regional tectonic of the North-West Java Basinal area. The results of structural mapping using regional 2D seismic data controlled by numbers of wells indicates study area is mostly located along NNE-NSW trending basement high structures (Figure 3). Structural development of the study area is dominated by series of normal faults system with some locally observed folds. In many seismic sections, faults geometry characterized by high to moderate dips. This specific geometry often interpreted as half graben and horst structures resulting from Eocene rifting. The structural geology of Bima field can be observed clearly at the WNW-ESE seismic line. It was dominated by N-S trending Normal fault that was probably related to the Eocene rifting which occurred predominantly at the west part of the study area. The main fault, occurred toward to the west, formed the half graben system which cut from basement to Parigi formation. However, others that placed at central part only cut the basement. The pre-Baturaja Sediment can be divided into two packages, which are syn-rift package and quiescence package while the post-Baturaja interval is the late post rift (sag) package.
Combining geological surface data and geostatistical model for Enhanced Subsurface geological model Alfadli, Muhammad Kurniawan; Natasia, Nanda; Haryanto, Iyan
Journal of Geological Sciences and Applied Geology Vol 2, No 2 (2017): Journal of Geological Sciences and Applied Geology
Publisher : Faculty of Geological Engineering, Universitas Padjadjaran

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24198/gsag.v2i2.13451

Abstract

AbstractThis paper emphasis the use of geological information gathered from surface mapping and subsurface data, the method that used was mainly utilizing statistical information and deterministic model interpreted. Comparison model was built to calculate the deviation between realization, the calculation was furthered can be used as a uncertainty to make a better decision to choose the best realization. Geostatistics is a branch of statistics focusing on spatial or spatiotemporal datasets. In geology, geostatistical is used for numerical calculation of subsurface approach with several data such as geophysical or geological observation. Geostatistics modelling have several parameters setup to obtain best approach model. The parameters namely lithological boundary, geological structure and random seed number. Process for modelling used 23 drilling data with various lithological type. Two type geostatistical method is applied for the data that is Indicator Kriging (IK) and Sequential Indicator Simulation (SIS) with grid size 1000x1000 and 2000x1500. Distribution of lithology begin without parameters. Resulted shown that the model not appropriate with geological surface data and mismatch lithology position. To obtained better model, several geological information is included before geostatistical calculation. From regional geology surface data is obtained geological formation within lithological information. Then, geological structure describes the geology fault and formation boundary.Keywords: Geostatistics, subsurface, enhanced model, variance, random seed number
Linking Petrography And Petrophysical Analysis In Carbonate Reservoir Characterization: Case Study In Baturaja Formation Offshore Northwest Java Natasia, Nanda; Alfadli, Muhammad Kurniawan; Arfiansyah, Kurnia; Hardiyono, Adi; Barkah, Mohamad Nursiyam; Haryanto, Iyan
Journal of Geological Sciences and Applied Geology Vol 2, No 2 (2017): Journal of Geological Sciences and Applied Geology
Publisher : Faculty of Geological Engineering, Universitas Padjadjaran

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24198/gsag.v2i2.13448

Abstract

AbstractLinking geological analysis with petrophysical characterization in complex carbonate reservoir is a chalangging task. Many previous researcher has proofed that depositional facies in carbonate reservoir has very little advantages in reservoir quality due to overprinted with diagenetic facies. The difficulties in characterized the carbonate may rise because one does not include some genetic, geometrical and petrophysical character of the pore space, both geometry and distribution. The aim of this study is to evaluate the reservoir rock typing in carbonate reservoir by comparing rock-fabric descriptions analyzed in thin section with laboratory measurements of porosity, permeability, capillarity, and Archie m values. Methodology employed for this study involved the examination of thin sections and the integration of routine analysis data following lucia’s pore classification scheme. The first step in characterized the petrophysical class is the determination of interparticle porosity by substracting the separate vug porosity from total porosity. The separate vug porosity is estimated in petrographic analysis in 325 thin section samples. Than estimating the value for un cored interval by determining the relationships between total porosity, separate vug porosity and sonic interval transit time. The petrographic analysis to estimating the separate vug porosity is a qualitative way, and so the value is not quantitative, but the trend is still implies the value so the relationships between porosity and sonic log can be quantified. Calibration of pore types to acoustic log response is accomplished by making a detailed log of porosity types described from thin sections and constructing Z-plots of total porosity and transit time from logs and separate-vug porosity from thin sections . The “m” value (lithology exponent or cementation factor) is different from the other terms in the Archie equation in that it is related to rock fabrics, specifically to vuggy porosity. Reservoir characterization by using this scheme has proofed that geological analysis made in detailed thin section can be a helpfull tool since the validation in tested and produced interval shows a verry good relationships. Keywords : Reservoir Characterization, Baturaja Fm., Carbonate, Petrophysics.
Slope Stability Analysis of East Ring Road Construction at Sadawarna Dam With Shear Strength Reduction Method Putra, Rafino Kurnia; Zakaria, Zufialdi; Alfadli, Muhammad Kurniawan; Sophian, Raden Irvan; Khoirullah, Nur; Firmansyah, Yusi
Journal of Geological Sciences and Applied Geology Vol 7, No 3 (2023): Journal of Geological Sciences and Applied Geology
Publisher : Faculty of Geological Engineering, Universitas Padjadjaran

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24198/gsag.v7i3.50589

Abstract

Slope stability has been a problem that studied on geotechnical works for the uncertainties such as varieties of soil behaviours to unpredicted failure of measurements and samplings. The Limit Equilibrium Method (LEM) has been popular for decades for its convenience but cannot determine displacement thus the result could be uncertain. As computational calculations have been developed, the Finite Element Method (FEM) began to use as a tool to not only determine factor of safety, but also determine displacement and forces that affect slope’s stability. This research was done to analysed slope stability using Shear Strength Reduction (SSR) and compared it to general method such as Limit Equilibrium Method (LEM). The research was conducted on a section in Sadawarna DAM ring road area, Subang, West Java. Slope on research area was divided into two layers with the bottom layer relatively non-cohesive compared to the top of layer. Both soil however dominantly consist with fine grain soil such as silt and clay. The upper layer of slope can contain more water with liquid limit of 73,46% compared to the lower layer with 68,27% liquid limit.  Simulation result showed slope that analysed using SSR method has Factor of Safety (FoS) 0,12 lower than LEM method. SSR method could be used to analysed pessimistic value at worst scenario and could predicted deformation of slope.
LITOFASIES ENDAPAN KUARTER DI WILAYAH DKI JAKARTA Listyono, Girlly Marchlina; Arfiansyah, Kurnia; Natasia, Nanda; Alfadli, Muhammad Kurniawan; Pranantya, Pulung Arya
Bulletin of Scientific Contribution Vol 14, No 1 (2016): Bulletin of Scientific Contribution
Publisher : Fakultas Teknik Geologi Universitas Padjadjaran

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (798.933 KB) | DOI: 10.24198/bsc.v14i1.9803

Abstract

Bay of Jakarta is covered of Qartenary deposits with terrestrial deposits intercalation with marine deposits. Interaction between those depositional environment produce deposits which have lithofacies variation. Rapid development of Jakarta impact on impossibility in finding outcrop. This research gives changes for detailed Quarternary deposit lithofacies study through 22 wells with depth range about 120-450 metres and depth total 6.556,61 metres. Terrestrial deposit characterized by domination of relatively coarse clastics and content of remaining roots, woods, plants, high content of quartz, lithic fragment, calcareous and oxidated appearace. Marine deposit characterized by finer clastics, contain remain of shells, fosil, coral, limestone fragments, glauconites, calcareous. The lithofacies variation of Quartenary depost from the wells indicate lateral and vertical variation change, also on coastline shifting either by transgression or regression.       Keywords : deposits, Jakarta, quartenary, sediment Jakarta merupakan daerah teluk yang tersusun oleh endapan kuarter dengan karakteristik litologi yang beragam. Sedimen penyusun endapan kuarter Jakarta dipengaruhi oleh proses sedimentasi lingkungan pengendapan darat dan laut. Interaksi antara dua lingkungan pengendapan tersebut menghasilkan endapan yang memiliki variasi litofasies. Dengan pesatnya pembangunan di Jakarta menjadikan kesempatan untuk melihat singkapan sangat kecil. Penelitian ini memberikan kesempatan untuk melihat litofasies endapan kuarter Jakarta dengan lebih jelas melalui 22 sumur bor dengan kedalaman berkisar 120 – 450 meter dan total tebal 6.556,61 meter. Endapan darat dicirikan oleh dominansi klastika yang relatif kasar dan kandungan sisa akar, kayu, tumbuhan, kaya butiran kuarsa, fragmen litik, kerikilan, serta sifat karbonatan dan kenampakan teroksidasi. Batas antara keduanya sepanjang periode Kuarter memperlihatkan variasi secara vertikal dan lateral dan perubahan garis pantai baik transgresi maupun regresi. Kata Kunci : endapan, Jakarta, kuarter, sedimen
Geomorfologi dan Ciri Fasies Vulkanik Pada Sungai Cihideung dan Ciparikalih, Sub Das Cibadak, Gunung Salak, Jawa Barat Natasia, Nanda; Mardiana, Undang; Alfadli, Muhammad Kurniawan
Bulletin of Scientific Contribution Vol 16, No 2 (2018): Bulletin of Scientific Contribution GEOLOGY
Publisher : Fakultas Teknik Geologi Universitas Padjadjaran

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (1443.787 KB) | DOI: 10.24198/bsc.v16i2.18439

Abstract

ABSTRACTSalak Mount is a volcanic complex located in the south of Jakarta. This mountain area is included in the area of Sukabumi Regency and Bogor Regency, West Java. The peak part is a forest area whose management of the forest area was originally under the Perhutani Public Corporation Forest Management Unit (KPH) Bogor, but since 2003 it has been an expansion area of the Gunung Halimun National Park, and is managed as Gunung Halimun-Salak National Park. This research begins with the analysis of topographic maps to determine the geomorphological characteristics of the study area. These geomorphological characteristics include river flow patterns, land use and slope. At this stage it can be distinguished as many as nine recognizable geomorphological units. The next stage is field observation to find out the surface geological conditions of the study area. at this stage two stratigraphic cross sections were made which passed the Cihideung and Ciparikalih. From the results of geomorphological analysis, the research area can be divided into nine geomorphological units which are compiled based on their morphographic, morphometric and morphogenetic characteristics. Two stratigraphic cross sections through the Cihideung River and Ciparikalih River trajectories are made based on field observations with a measured section method. In both trajectories, there are six volcanic facies that make up the research area.. Keywords: Salak Mount, Cibadak Sub Das, Volcanic Facies, Geomorphology ABSTRACKGunung Salak merupakan kompleks gunung berapi yang terletak di selatan Jakarta. Kawasan rangkaian gunung ini termasuk ke dalam wilayah Kabupaten Sukabumi dan Kabupaten Bogor, Jawa Barat. Bagian puncaknya merupakan kawasan hutan yang pengelolaan kawasan hutannya semula berada di bawah Perum Perhutani Kesatuan Pemangkuan Hutan (KPH) Bogor, tetapi sejak 2003 menjadi wilayah perluasan Taman Nasional Gunung Halimun, dan dikelola sebagai Taman Nasional Gunung Halimun-Salak. Penelitian ini diawali dengan analisis peta topografi untuk mengetahui ciri geomorfologi daerah penelitian. Ciri ciri geomorfologi tersebut diantarana pola pengaliran sungai,  tata guna lahan, serta kemiringan lereng. Pada tahapan ini dapat dibedakan sebanyak sembilan satuan geomorfologi yang dapat dikenali. Tahapan selanjutnya adalah pengamatan lapangan untuk menetahui kondisi geologi permukaan daerah penelitian. pada tahapan ini dibuat dua buah penampang stratigrafi yang melewati sub Das Cihideung dan sub DAS Ciparikalih. Dari hasil analisis geomorfologi, daerah penelitian dapat dibagi menjadi sembilan satuan geomorfologi yang disusun berdasarkan ciri morfografi, morfometri dan morfogenetiknya. Dua buah penampang stratigrafi melalui lintasan Sungai Cihideung dan Sungai Ciparikalih dibuat berdasarkan pengamatan lapangan dengan metoda penampang terukur. Pada kedua lintasan tersebut dapat diketahui enam fasies vulkanik yang menyusun daerah penelitian. Kata Kunci: Gunung Salak, Sub Das Cibadak, Fasies Vulkanik, Geomorfologi.
Stratigrafi Vulkanik Sub DAS Cibadak Implikasinya terhadap Kegiatan Gunungapi Salak Lereng Timur MUTAQIN, DEDEN ZAENUDIN; Mardiana, Undang; Mohammad, Febriwan; Alfadli, Muhammad Kurniawan; Natasia, Nanda
Bulletin of Scientific Contribution Vol 17, No 1 (2019): Bulletin of Scientific Contribution GEOLOGY
Publisher : Fakultas Teknik Geologi Universitas Padjadjaran

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24198/bsc.v17i1.20904

Abstract

Penelitian Stratigrafi rinci mengenai daerah vulkanik masih jarang dilakukan. Hal ini biasanya dikarenakan oleh kondisi lapangan yang sulit ditempuh. Akan tetapi, penelitian fasies vulkanik  ditujukan untuk mengetahui perkembangan gunungapi secara geologi baik dari segi kebencanaan atau potensi. Penelitian ini berlokasi di Sub DAS Cibadak Lereng Timur Gunung Salak untuk mengetahui perubahan litologi baik secara lateral maupun vertikal. Permasalahan dipecahan dengan Observasi lapangan dan karakteristik permukaan. Data lapangan berupa lintasan-lintasan stratigrafi berdasarkan daerah sub DAS Cibadak yang terdiri dari sungai cibadak, cikuda, cipanengah dan cimenteng. Berdasarkan fasies vulknik dari keseluruhan analisis , terdapat 6 kelompok fasies dari muda ke tua yaitu Block and ash flow deposit 2 salak, lava flow 2 salak, block and ash flow deposit 1 salak, lava flow 1 salak, pumice flow deposit salak dan scoria flow deposit pra salak.
POLA PERSEBARAN DAN ESTIMASI CADANGAN TANAH MERAH PADA DESA TANJUNG KECAMATAN SURIAN KABUPATEN SUMEDANG MUTAQIN, DEDEN ZAENUDIN; MARDIANA, UNDANG; MOHAMMAD, FEBRIWAN; ALFADLI, MUHAMMAD KURNIAWAN
Bulletin of Scientific Contribution Vol 18, No 2 (2020): Bulletin of Scientific Contribution : GEOLOGY
Publisher : Fakultas Teknik Geologi Universitas Padjadjaran

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24198/bsc.v18i2.27826

Abstract

Kesuburan alami tanah merah mengandung unsur hara makro seperti nitrogen, fosfor, dan kalium meningkatkan produksi tanaman. Penambangan tanah merah tidaklah semudah yang dibayangkan karena karena belum tahu perkiraan ketebalan tanah merah untuk kearea prospek. Tahapan eksplorasi guna mengetahui persebaran dan estimasi cadangan yang dapat mengurangi resiko dalam upaya penambangan tanah merah. Metode penelitian  yang digunakan berupa pengukuran geolistrik 1D dengan jumlah 15 titik pengukuran dengan luas 30 ha. Tujuan dari penelitian ini yaitu mengetahui pola sebaran dan estimasi cadangan tanah merah pada desa Tanjung kecamatan Surian kabupaten Sumedang.  Hasil penelitian menunjukan tanah merah memiliki niali resistivitas >30 ohm.meter dengan ketebalan  berkisar 3.5-20 meter dengan pola persebaran acak  dengan warna coklat kemerahan, berbutir lempung lanauan. Kemudian pada bagian bawahnya berupa batulanau, dan batupasir dari formasi batuan sedimen.Kata kunci : Resistivitas, Surian, Tanah merah
ZONA PRODUKTIF RESERVOIR HIDROKARBON BEDASARKAN ANALISIS PETROFISIKA PROBABILISTIK PADA FORMASI BATURAJA, DI LAPANGAN FM, CEKUNGAN SUMATERA SELATAN, MENGGUNAKAN DATA WELL LOG DAN CORE Ibrahim, Farrel Malik; Mardiana, Undang; Mohammad, Febriwan; Saputro, Julian; Alfadli, Muhammad Kurniawan
Bulletin of Scientific Contribution Vol 21, No 1 (2023): Bulletin of Scientific Contribution : GEOLOGY
Publisher : Fakultas Teknik Geologi Universitas Padjadjaran

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24198/bsc.v21i1.45329

Abstract

Analisis petrofisika merupakan salah satu kegiatan analisis dalam eksplorasi minyak dan gas bumi yang bertujuan untuk mengetahui lapisan reservoir hidrokarbon disuatu sumur. Lapangan ”FM” berada di Cekungan Sumatera Selatan daerah tinggian Musi. Formasi yang prospek menjadi reservoir hidrokarbon pada lapangan ini adalah Formasi Baturaja yang berlitologi batugamping dan berumur miosen awal. Hasil dari analisis elektrofasies dan data mudlog didapatkan bahwa lingkungan pengendapan dari Formasi Baturaja  pada lapangan ini adalah lingkungan reef front dan back reef lagoon. Fasies reef dicirikan oleh adanya penebalan pada sumur FM-1 dan memiliki komponen batugamping terumbu, sementara fasies back-reef cenderung tipis dan berupa batugamping klastik. Metode analisis petrofisika yang digunakan pada penelitian kali ini adalah analisis petrofisika probabilistik dengan menghitung volume tiap komponen mineral dan fluida. Pemilihan analisis petrofisika probabilistik dinilai karena metode ini cukup baik digunakan pada sumur pengembangan. Hasil penentuan zona produktif reservoir di lapangan FM didapatkan sebesar 13,11 meter di FM-1, 3,81 meter di FM-2, dan 1,07 meter di FM-3. Zona produktif reservoir hidrokarbon berada pada top baturaja fasies reef pada FM-1 dan back-reef pada FM-2 dan FM-3. Hasil perhitungan petrofisika probabilistik akan lebih baik jika terdapat penambahan data berupa analisis petrografi dan XRD sebagai pendukung mineral penyusun batuan dan volume dari tiap komponen mineral.