Identifikasi Panas Bumi Diwak dan Derekan Kecamatan Bergas Kabupaten Semarang dengan Menggunakan Metode Audiomagnetotellurik

Audio-Magnetotellurics (AMT) surveys has been conducted in September 2013 in the Diwak and Derekan geothermal fields. The purpose of the audio-magnetotelluric surveys to indicate heat source, reservoir, and cap rock. The data obtained from the field was apparent resistivity, phase difference, and coherence as a function of frequency are processed using softwere package WinGLink then matched with regional geological information studies, and the results are interpreted.Characterization of geothermal systems include the caprock with a resistivity of 0-10Ωm value where the area is a zone of conductivity. Then the reservoir area is suspected to have a resistivity value with arange of 50-500 Ωm with a depth of about 500 m. In the heat source located in a geothermal system resistivity values > 500Ωm with a depth of about 1.5 km

Interpretasi Bawah Permukaan Daerah Sumber Air Panas Diwak-derekan Berdasarkan Data Magnetik

Research has been carried out using a magnetic method that aims to interpret the subsurface structure of the area hot springs Derekan - Diwak based on the total magnetic field anomaly data. It also aims to investigate the geothermal system in the area.Some 99 points measurement areas were measured using PPM (Proton Precession Magnetometer) geometrics type GSM19T models to get the value of the total magnetic field and two points as a base station simultaneously measured using the PPM G856X models. Measurement data is processed by the daily variation correction and IGRF (International Geomagnetic Reference Field) correction. The data has been used to create a contour corrected total magnetic field anomalies and subsurface cross sections involving the upward continuation and reduction to the poles.The results of study showed the total magnetic field anomaly closure pair of positive and negative closure indicate a fault zone below the surface. Interpretation is strengthened by the results of the modeling showed two faults of Derekan - Diwak areas trending southwest- northeast. This fault zone is a media outlet fluid to the surface in the area of geothermal systems

Identifikasi Struktur Bawah Permukaan Menggunakan Metode Geolistrik Konfigurasi Schlumberger di Area Panasbumi Desa Diwak dan Derekan Kecamatan Bergas Kabupaten Semarang

Diwak and Derekan is one of geothermal manifest which exist in geothermal system of Ungaran. Geoelectric method schlumberger configuration is one of the geophysical methods that used in the exploration of natural resources below the surface. The purpose of researching is to know layer of subsurface structure which control Diwak and Derekan geothermal manifest.Field measurement data in the field are potential differences and currents which can be used to calculate apparent resistivity value. After apparent resistivity value is created then processed using IPI2WIN program to know resistivity value in each layer with geology information validation.The results of the study showed six geoelectric layer of rock that is composed of layers of mudstone, siltstone, tuff, sandstone brecia and pasirtuf with resistivity values and different thicknesses. Interpretation of manually indicate the presence of two down faults that are weak zone where the fluid surface discharg

Interpretasi Bawah Permukaan Sistem Panas Bumi Diwak dan Derekan Berdasarkan Data Gravitasi

Research has been carried out using a gravity method that aims to interpret the subsurface structure of the Diwak - Derekan hot springs area based on the Bouguer anomaly data. It also aims to investigate the geothermal system in the area. The data aquisition was taken using gravitymeter Lacoste & Romberg.Data processing had been done with high correction tool, tidal correction, drift correction, gravity absolute correction, gravity theoretical correction, free air correction, Bouguer correction, terrain correction to get the complete Bouguer anomaly. Bouguer anomolay is projected to flat plane and upward continuation is used to separate the regional and residual anomaly. For 2D modelling interpretation by Grav2DC software.The results of study showed the complete Bouguer anomaly contour pair of positive and negative contour indicate a fault zone below the surface. Interpretation is strengthened by the results of the modeling showed a fault of Diwak - Derekan areas trending southwest- northeast. This fault zone is used as a media outlet fluid to the surface of geothermal systems

Identifikasi Sifat Fisis Batuan Reservoir Karbonat Menggunakan Inverse Acoustic Impedance (AI) Model Sparse Spike pada Lapangan “ABDUH” Formasi Kujung Cekungan Jawa Timur Utara

Physical rocks properties identification on "ABDUH" field, North East Java Basin has been done by acoustic impedance seismic inversion. The research aim conducted to predict the physical properties of rock by acoustic impedance inversion value and the porosity distrubution by linier programming sparse spike. Sparse spike linear programming method assumes that a reflectifity regarded as the model a series of rarely spike and the big value deconvoluted with a new spike smaller than before maked it more accurated. This study used at single well and seismic 3D data post stack time migration is the area on research. Then with assumes a linear relationship between acoustic impedance and log porosity log based crossplot, obtained linear equation which was used to get the distribution of porosity from the distribution of acoustic impedance. Inversion results show the distribution of reefs on Kujung Reef formation has the porosity value 21-27% and the acoustic impedance vaue 17.000 to 28.000 ft/s.g/cc

Interpretasi Pola Aliran Fluida Panas Bumi dengan Metode Spontaneous-potential (SP) dan Suhu Permukaan Dangkal di Lereng Utara Gunung Telomoyo Kabupaten Semarang

The model heat flow at Telomoyo Mountain Semarang District has measured and identified using spontaneous potensial and shallow temperature surface methods.Field data has proceed using Microsoft Excel which the result entered to Surfer11 with the result map contour of SP and temperature distribution. The result showed that range anomaly SP about -40mV-70mV and distribution of temperature which has temperature range 23,5º-31ºC. The direction of heat flow direct from South to North-East

Pemodelan Steady State Sistem Panas Bumi Daerah Sumber Air Panas Diwak-derakan dengan Menggunakan Software Hydrothrem 2.2

Steady State Modeling has been done hot springs Diwak-Derekan using Hydrotherm 2.2 software which aims to model numerically geothermal system Diwak-Derekan in Steady State conditions. The results form the output of Hydrothrem 2.2 Temperature Distribution and visualization of the data carried Temperature Distribution.Extent of the study area is 16 km x 16 km, where there is a buffer area in the outer portion of the study area. then made construction research area consisting of several slice and block research. Used topographic data using secondary data, and topographic data modeling made in accordance with the slice. Each slice of the construction area made initial research model that contains the physical parameters. Due to the limitations of the data parameters of physics, then some physical parameters of the data analogous to data from Mount Merapi and soil mechanics research data Diponegoro University Dam, physical parameters and the data is made in the form of program listings in the form of input for software Hydrothrem which Hydrotherm Software run the program until the year to 200,000 by year interval 10,000 years.The results of data visualization is seen that the temperature distribution for the data in the year to 80,000 and so no change is significant, this indicates that in the year to 80,000 already reached Steady State conditions. Khono (2000) said, geothermal system reach steady state condition between 200.000-500.000 years, its because using analogical data from Merapi Vulcano and ground mechanic Diponegoro University dam. Manifestations of geothermal systems around the emergence of hot water Diwak-Derekan a geothermal system associated with sediments. This is confirmed by studies based on the gravity method which is done around the study area, where there are faults trending down southwest - northeast parallel to Kali and Kali Jumbleng Klampok, where after a qualitative interpretation there are 4 layers of rock, where the top layer is sediment layer has a depth of about 3 km