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Perpindahan Panas pada Media Berpori Menggunakan Metode Elemen Hingga Surya Ningsih; Wahyu Srigutomo
SAINTIFIK Vol 4 No 2 (2018): volume 4 nomor 2 juli 2018
Publisher : Universitas Sulawesi Barat

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (999.253 KB) | DOI: 10.31605/saintifik.v4i2.182

Abstract

Masuknya aliran panas dari bawah reservoir ke dalam medium berpori di dalamnya mempengaruhi kondisi tekanan, entalpi, dan temperatur di dalam reservoir. Hal ini terjadi karena panas mengalir dari daerah bertemperatur tinggi ke daerah bertemperatur lebih rendah. Panas mengalir melalui daerah patahan (fracture zone) yang memiliki permeabilitas dan porositas lebih tinggi dari daerah sekitarnya di dalam reservoir untuk kemudian terjadi perpindahan panas secara konduksi menuju daerah sekitarnya. Tulisan ini mensimulasikan proses perpindahan panas dengan mengamati distribusi temperatur dan aliran fluida pada medium berpori. Metode numerik yang digunakan adalah metode elemen hingga. Hasil yang ditampilkan adalah distribusi tekanan, kecepatan aliran fluida, dan distribusi temperatur dan kemudian diinterpretasikan.Kata kunci: permeabilitas, porositas, kecepatan, distribusi temperatur, metode elemen hingga.
Analisis Parameter Anomali SP Menggunakan Metode Inversi Non linier Pendekatan Linier Fajriani Fajriani; Hardi Hamzah; Wahyu Srigutomo; Prihamdhanu Mukti Pratomo
SAINTIFIK Vol 5 No 1 (2019): Volume 5 Nomor 1
Publisher : Universitas Sulawesi Barat

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (134.577 KB) | DOI: 10.31605/saintifik.v5i1.193

Abstract

nterpretasi anomali self-potential (SP) model geometri sederhana (fixed geometry) sederhana, dilakukan untuk menghitung kedalaman, sudut polarisasi benda, moment dipole listrik, dan bentuk struktur benda dibawah permukaan yang mempengaruhi data SP yang diamati diatas permukaan. Dalam mengidentifikasi parameter anomali SP akibat dari model fixed geometry dibawah permukaan bumi dapat dilakukan dengan cara pemodelan inversi. Dalam tulisan ini pemodelan inversi diselesaikan menggunakan pendekatan linier dengan metode least-square terbobot dan metode Levenberg-Marquardt. Kedua metode ini diaplikasikan untuk menentukan nilai parameter dari anomali self-potential akibat struktur sesar, dengan menganggap struktur sesar menyerupai bentuk lempeng. Metode least-square terbobot dan Levenberg-Marquardt mampu mengikuti pola hasil data pengukuran di lapangan. Kedua metode inversi tersebut efisien karena proses perhitungannya yang relatif singkat serta nilai parameter model struktur lempeng hasil perhitungan kedua metode tersebut menunjukkan hasil yang sama hanya terdapat sedikit selisih perhitungan pada nilai kemiringan sudut lempeng.Kata kunci: anomali self-potential, fixed geometry, pendekatan linier
PEMODELAN ANOMALI SELF-POTENTIAL GEOMETRI TETAP DAN INVERSI GLOBAL OPTIMASI VERY FAST SIMULATED ANNEALING Hardi Hamzah; Mohammad Heriyanto; Wahyu Srigutomo
PHYDAGOGIC : Jurnal Fisika dan Pembelajarannya Vol 1 No 1 (2018): PHYDAGOGIC : Jurnal Fisika dan Pembelajarannya
Publisher : Universitas Sulawesi Barat

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (385.76 KB) | DOI: 10.31605/phy.v1i1.222

Abstract

Penelitian ini membahas interpretasi anomali self-potential (SP) berdasarkan asumsi model bergeometri sederhana yang tetap (fixed-geometry) berbentuk lempeng di bawah permukaan. Inversi anomali SP berupa data sintetik untuk mendapatkan parameter-parameter model lempeng dilakukan dengan menggunakan metode global optimasi Very Fast Simulated Annealing (VFSA). Nilai parameter model hasil inversi memiliki nilai yang hampir sama dengan nilai parameter model yang membangkitkan data sintetik. Hal ini mengindikasikan validasi dan efektivitas skema inversi yang dibuat untuk diterapkan pada anomali SP hasil pengukuran sesungguhnya di lapangan.
CO2 Thermal Conductivity Detection in Gas Mixture for Concentration Measurement Using Bridge Configuration of Thermopiles Eko Satria; Melany Febrina; Mitra Djamal; Wahyu Srigutomo; Martin Liess
Science and Technology Indonesia Vol. 7 No. 4 (2022): October
Publisher : Research Center of Inorganic Materials and Coordination Complexes, FMIPA Universitas Sriwijaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (947.182 KB) | DOI: 10.26554/sti.2022.7.4.443-448

Abstract

In this research, improvisation was carried out by modifying the market IR thermopile which functions as a thermal conductivity detector to measure the concentration of CO2 gas in the gas mixture. Four thermopiles are configured with a Wheatstone bridge with the aim of increasing the accuracy of the measurement system in detecting changes in CO2 concentration in the gas mixture (N2 and CO2). Using the bridge configuration of these four thermopiles, this measurement system can measure changes in CO2 concentration in small orders. The sensor developed is easy to manufacture, low cost, and has high linearity as evidenced by a correlation coefficient of 0.9943. From the experiments carried out, the sensor works quite accurately in detecting CO2 concentrations with the sensor’s sensitivity of -88.19 Volt/%, the detection range is 0% to 100%, and the RMS error value is 2.25.
Study of Deep Sounding Time-Domain Electromagnetic (TDEM) Method Using Horizontal Electric Dipole to Infer Subsurface Resistivity Structure Wahyu Srigutomo; Tsuneomi Kagiyama; Wataru Kanda; Hisashi Utada
Indonesian Journal of Physics Vol 16 No 4 (2005): Vol. 16 No. 4, October 2005
Publisher : Institut Teknologi Bandung

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (556.052 KB)

Abstract

Electromagnetic methods to infer subsurface resistivity structure particularly in volcanic and hydrothermal regions are considered highly effective to apply. Time domain electromagnetic (TDEM) method as one of them, is a robust method utilizing controlled-galvanic source which has higher ability to penetrate deeper structure. This paper tries to elaborate the theoretical formulation of TDEM with a long-grounded current wire for a layered-earth problem, the mathematical inversion algorithm to find the suitable model for interpretation as well as its sensitivity analysis, and the application to synthetic and real measured data.
VLF Data Analysis Through Transformation Into Resistivity Value: Application tTo Synthetic and Field Data Wahyu Srigutomo; Asep Harja; Doddy Sutarno; Tsuneomi Kagiyama
Indonesian Journal of Physics Vol 16 No 4 (2005): Vol. 16 No. 4, October 2005
Publisher : Institut Teknologi Bandung

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (917.556 KB)

Abstract

Transformation of VLF-EM signals, which are approximated as the real and imaginary components of the ratio between the vertical and the horizontal components of magnetic fields was carried out in this study to improve the quantitative interpretation aspect of VLF analysis. The transformation filter has been tested using synthetic data generated by a two-dimensional finite element algorithm that provides VLF responses for several models typically encountered in VLF surveys. The transformed apparent resistivity profiles show good agreement in value and pattern to those modeled by the finite element algorithm. The transformation was applied to the field data and further analysis was conducted by inverting the recorded original VLF-EM signals and the transformed apparent resistivity into a two-dimensional resistivity-depth section. From the comparison with the dc-resistivity-depth section obtained previously, the resulted resistivity section revealed the general features of the subsurface structure.
Quantitative Analysis of Self-Potential Anomaly: Derivative Analysis, Least-Squares Method and Non-Linear Inversion Wahyu Srigutomo; Eleonora Agustine; M. Habri Zen
Indonesian Journal of Physics Vol 17 No 2 (2006): Vol. 17 No. 2, April 2006
Publisher : Institut Teknologi Bandung

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (574.614 KB)

Abstract

Despite the broadly usage in geophysical fields due to its non-intrusiveness, inexpensiveness and fast deployment, self-potential (SP) method still posses challenges in the interpretation. In this work, quantitative identification of SP parameters such as the shape factor of cylindrical and spherical objects, the depth of burial, the polarization angle and the electric dipole moment is addressed. Three approaches of quantitative interpretation are used, i.e., a derivative method, a least-squares method and an iterative inversion based on the Levenberg-Marquardt method. The above approaches were first tested on a theoretical synthetic model, where a close agreement between the presumed and calculated parameters was obtained. Application to the real data was conducted by analyzing the SP anomaly obtained from a buried cylindrical conductive object at certain depth.
Self Potential Modeling for Investigation of Shallow Structure in Volcanic Region: a Study Case at Domas Crater, Tangkuban Parahu Volcano, West Java Wahyu Srigutomo; Alamta Singarimbun; Adhitya S. Sunarya; Prihandhanu M. Pratomo; Anggie Susilawati; Candra E. Novana; Deny Juanda Puradimaja; Eleonora Agustine
Indonesian Journal of Physics Vol 21 No 2 (2010): Vol. 21 No. 2, April 2010
Publisher : Institut Teknologi Bandung

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (1087.52 KB) | DOI: 10.5614/itb.ijp.2010.21.2.1

Abstract

Quantitative numerical modeling of self-potential (SP) anomaly associated with subsurface electric current density that is attributed to cross-coupling between fluid flow and electrical conductivity distributions has been conducted. The modeling scheme was applied to an area in the vicinity area of Domas crater, Tangkuban Parahu volcano in West Java. The field surveys at domas were conducted from mid-2008 until mid-2009. The main objective of this researchis to obtain a quantitative model that is possible to explain the shallow convective hydrothermal system in the eastern side of the volcano by making comparison between SP anomaly measured on the surface with theoretical anomaly resulted from modeling. Since the modeling scheme requires information on the subsurface resistivity structure, we performed measurement and interpretation of 2-D resistivity at Domas crater. The measurement of CO2 emission that is commonly associated with magmatic gas migration patterns through fracture system was also carried out on the same SP and resistivity lines. Fluid velocity vector was calculated by solving the coupled Darcy’s and energy equations involving heat transfer terms by both convection and conduction. The subsurface electric current source distribution was calculated by solving the coupled equation of velocity and potential gradients. The results show that the fluid flow patterns around Domas Crater which in addition is controlled by topographic effect; it is also influenced by thermal fluid flows through relatively high permeability zone beneath the Domas Crater.
Resistivtiy Structure in Kamojang Geothermal Field Derived from CSAMT Data Enjang Jaenal Mustopa; Wahyu Srigutomo; Doddy Sutarno; Umar Fauzi
Indonesian Journal of Physics Vol 22 No 1 (2011): Vol. 22 No. 1, January 2011
Publisher : Institut Teknologi Bandung

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (307.747 KB) | DOI: 10.5614/itb.ijp.2011.22.1.4

Abstract

Controlled-source audio frequency magnetotelluric (CSAMT) survey consisting of 60 soundings has been carried out in the Kamojang geothermal field to delineate resistivity structure correlated to the present geothermal reservoir. The transmitter site was located about 3 − 5 km in the south-west of the survey area. The sounding sites were distributed irregularly and the distance between each of them varied from 200 to 500 m, covering the Kamojang Geothermal area. The two dimensional (2D) inversion scheme was applied to interpret the CSAMT data. The results show that the subsurface resistivity structures in the Kamojang geothermal field consists of three types of resistivity features correlated to the existing geothermal reservoir in the area, that is, the overburden (first layer) having resistivity value of 30 – 150 ohm.m and thickness of 30 to 100 m overlaying the intermediate (second) layer which has an extremely low resistivity of 3 – 10 ohm.m with 500 – 1200 m thick. This low resistivity layer can be considered as a hydrothermal alteration zone comprising the impermeable layer or sealing cap rock. Finally, the third layer which is relatively more resistive than the second layer with resistivity of 30 − 100 ohm-m. From the 3D view of the low resistivity anomaly (<10 ohm.m) considered as a hydrothermal alteration zone, it is obtained that altered zone is deep in the south-west and becomes shallow in the north-east of the area.
Resistivity Imaging of Mataloko Geothermal Field By Mise-Á-La-Masse Method Enjang Jaenal Mustopa; Wahyu Srigutomo; Doddy Sutarno
Indonesian Journal of Physics Vol 22 No 2 (2011): Vol. 22 No. 2, April 2011
Publisher : Institut Teknologi Bandung

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (616.313 KB) | DOI: 10.5614/itb.ijp.2011.22.2.3

Abstract

Mise-á-la-masse (MAM) measurement has been carried out in the Mataloko geothermal field, Flores, East Nusa Tenggara. The survey was conducted along 16 survey lines in a radial configuration to collect 176 sounding sites. The purpose of the measurement is to image a promising reservoir zone and to correlate the results with the previous geosciences surveys for locating the best drilling target. Three-dimensional (3D) inversion scheme was applied to interpret MAM data. The subsurface resistivity structure obtained from 3D inversion result shows that a low resistivity (1 − 10 ohm.m) structure is widely distributed in the southwest and northeast of the well MT-3/MT-5 at the depth 0 − 100 m. On the other hand, in the deeper part of the survey area, it is recognized that a resistivity in the western part is lower than in the eastern part of the area. The fluid flow tests of well MT-5 produced dry saturated steams of 19.3, 12.6 and 17.4 ton/h at wellhead pressures of 4.0, 6.0, and 5.0 kscg, respectively. Furthermore, the fluid has high enthalpies whose values are 2746, 2755, 2763, 2768, and 2771 kJ/kg at wellhead pressure of 4.0, 5.0, 6.0, 7.0, and 7.5 kscg, respectively. The incorporation of MAM data analyses results with the geosciences data makes it possible to recommend the location of the best target for the drilling site.
Co-Authors Abdullah, Adi Rahmansyah Amir Acep Purqon Acep Purqon Adam Sukma Putra Adhitya S. Sunarya Adi R.A. Abdullah Alamta Singarimbun Alan Maulana Alan Maulana Alief Sadlie Kasman Anggie Susilawati Anwar, Hairil Ari Setiawan Arizal Akbar Zikri Asep Harja Asep Harja Asep Saefullah Azrul Azwar Bakrun Bakrun Candra E. Novana Deny Juanda Puradimaja Dini Andriani Dini Fitriani Doddy Sutarno Doddy Sutarno Doddy Sutarno Doddy Sutarno Doddy Sutarno Doddy Sutarno Eddy Supriyana Eleonora Agustine Eleonora Agustine Eleonora Agustine Eleonora Agustine Enjang Jaenal Mustopa Enjang Jaenal Mustopa Enjang Jaenal Mustopa Fajriani Fajriani Fajriani Fajriani Fariduzzaman Fariduzzaman Fourier Dzar Eljabbar Latief Frafti Rejeki Fungki Iqlima Nasyidiyah Ghany Hanifan Muslim Hairil Anwar Hairil Anwar Hairil Anwar Halawa Ernwati Hapsoro, Cahyo Aji Harapan Marpaung Hardi Hamzah Harry Mahardika Haryo Seno Hendra Gunawan Herlan Darmawan Herlin Tarigan Hisashi Utada Humolungo, Ismail Husnul Hamdi Husnul Hamdi, Husnul I G. P. F. Soerya Djaja I Gede Putu Fadjar Soerya Djaja Imam Suyanto Imran Hilman Mohammad Imran Hilman Mohammad Irwan Ary Darmawan irwan meilano Irzaman, Irzaman Ismail Humolungo Jayawarsa, A.A. Ketut Joko Sampurno Kartika Hajar Kirana Kumalasari, Ratih Kuncoro, Alvina Kusumadewi Linus Pasasa M. Habri Zen Mahardika, Harry Maria Evita Martin Liess Martin Liess Melany Febrina Mitra Djamal Moh Yasin Mohammad Heriyanto Mohammad Heriyanto Muhamad Hilmi Aufa Muhammad Abdilllah Budianto Nadhira Gunawan Ni Ketut Lasmia Nina Siti Aminah Pepen Supendi Pratomo, Prihamdhanu Mukti Prihamdhanu Mukti Pratomo Prihandhanu M. Pratomo Purnama, Dikdik Sidik Putra, Heriansyah Rahmi Elzufiah Rakotovao Lovanantenaina Omega Rasito Tursinah, Rasito RATIH KUMALASARI Ratih Kumalasari Retna Apsari Richardo Barry Astro Rifky Nauval Rostikwati, Diana Ayu Ruddy Kurnia Satria, Eko Seno, Haryo Sesri Santurima Setyanto Cahyo Pranoto Sidik, Adi Permana Sitti Balkis Sparisoma Viridi Sumintadireja, Prihadi Suprijadi Suprijadi Suprijadi Suprijadi Supriyadi Supriyadi Surya Ningsih Surya Ningsih Suryanto, Wiwit Tsuneomi Kagiyama Tsuneomi Kagiyama Tsuneomi Kagiyama Umar Fauzi UMAR FAUZI Umar Said Wahyu Hidayat Wahyudi Wahyudi Warsa warsa Wataru Kanda Yanti Yanti Yazid Bindar Yuant Tiandho Zulfahmi Zulfahmi Zulfahmi Zulfahmi Zulhendra Zulhendra