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IDENTIFIKASI BATAS SUB-CEKUNGAN HIDROKARBON MENGGUNAKAN ANALISIS SHD (SECOND HORIZONTAL DERIVATIVE) DAN SVD (SECOND VERTICAL DERIVATIVE) BERDASARKAN KORELASI DATA GAYABERAT DAN SEISMIK Wuri Andari; Karyanto Karyanto; Riski Kurniawan
Jurnal Geofisika Eksplorasi Vol 5, No 1 (2019)
Publisher : Engineering Faculty Universitas Lampung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.23960/jge.v5i1.23

Abstract

Gravity method generally can read the difference of rock density to identify subsurface structures. This research was conducted in Riau area with the aim of knowing fault and subsurface structure, and determining sub-basin boundary. Data processing was done by using spectral analysis, SHD and SVD analysis, and 2D modeling then later correlated with seismic section to find out the subsurface structure of research area. The results showed that the bouguer anomaly value had a range of values between 5.6 mGal to 33.2 mGal with a surface density of 1.95 g / cc. High anomaly were in the eastern region and low anomaly were in the NW - SE trending region. 6 low anomalies indicated as a sub-basin pattern were separated by a relatively high altitude area of North West Southeast. The average residual anomaly depth was about 2.3 km. Based on the 2D subsurface modeling results, there was layer structure from the youngest to eldest that were alluvial deposits, Petani Formation, Sihapas group and granitic rock as the base rock. The projected subsurface section to surface showed 5 sub-basins with basin width 4-12 km located in the sub-basin and fault indication area.
IDENTIFIKASI STRUKTUR BAWAH PERMUKAAN MENGGUNAKAN METODE MAGNETOTELLURIK 2D DI DAERAH CEKUNGAN BINTUNI SEBAGAI POTENSI HIDROKARBON Ririn Yulianti; Syamsurijal Rasimeng; Karyanto Karyanto; Hidayat Hidayat; Noor Muhammad Indragiri
Jurnal Geofisika Eksplorasi Vol 4, No 2 (2018)
Publisher : Engineering Faculty Universitas Lampung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.23960/jge.v4i2.18

Abstract

Magnetotelluric research was done in hydrocarbon prospect area of Bintuni basin, West Papua province. The purpose of this research is to identificate hydrocarbon prospect in subsurface structure using 2D resistivity section. Data processing step for the research are; (i) Data transformation from time domain to frequency domain using Fourier transformation. (ii) Filtering process using Robust No Weight, Robust Rho Variance and Robust Ordinary Coherency. (iii) XPR selection and formatting data into EDI file. (iv) 2D resistivity section modeling using inversion. The result of this research based on 2D resistivity section in Klasafat formation have resistivity value about 1 – 20 Ωm. From 0 until 1000 meter below the surface the main lithology is claystone that identified as caprock. Kemblengan formation have resistivity value about 20 – 90 Ωm in 3500 meter under surface with main lithology lime-sandstone and identified as a reservoir. Tipuma formation have resistivity value about 0.62 – 2 Ωm in 8000 meter under surface with main lithology claystone. Kemun formation have resistivity value about 20 – 32 Ωm in 6000 meter under surface with main lithology sandstone and identified as a basement.
PENGOLAHAN DATA MIKROTREMOR BERDASARKAN METODE HVSR DENGAN MENGGUNAKAN MATLAB Winda Styani Yuliawati; Syamsurijal Rasimeng; Karyanto Karyanto
Jurnal Geofisika Eksplorasi Vol 5, No 1 (2019)
Publisher : Engineering Faculty Universitas Lampung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.23960/jge.v5i1.22

Abstract

The research has conducted to get the result of Matlab program for microtremor data processing. The purpose of this research is to apply Matlab software into microtremor data processing. The microtremor is the ground motion to identify earthquake vulnerability by using HVSR (Horizontal to Vertical Spectral Ratio) method. The HVSR method for comparing both of horizontal component and vertical component on microtremor wave to obtain the result dominant frequency(f0) based on the high spectrum H/V value from the analysis of HVSR curve. Based on this research which concludes that microtremor data processing has processed using Matlab software. The result of this data processing gives similar value from the geopsy software. The value of dominant frequency by Matlab software and geopsy software calculation are classified on the site class type II which is dominantly alluvium. Whereas, the result of dominant period by geopsy and Matlab are classified on the site class type I which shows as the bedrock.
PEMODELAN 3D STRUKTUR BAWAH PERMUKAAN GUNUNGAPI AGUNG PROVINSI BALI MENGGUNAKAN METODE GAYA BERAT Nasyratul Ilmi; Karyanto Karyanto
Jurnal Geofisika Eksplorasi Vol 5, No 2 (2019)
Publisher : Engineering Faculty Universitas Lampung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.23960/jge.v5i2.30

Abstract

Under surface structure, 3d modelling of Agung volcano in Bali had been conducted by using gravity methods. This research aims to identify the magma chamber and make a model below the surface of the Great Volcano of Bali Province by using gravity anomaly data. Data processing methods performed in this research were consists of six steps: (i) arrangement the contour map of Bouguer anomaly, (ii) spectrum analysis, (iii) anomaly regional and residual separation, (iv) Second Vertical Derivative analysis, (v) cross-section of subsurface geology construction by using 3D (inverse modelling), (vi) qualitative and quantitative interpretation. Anomaly Bougeur contour map result shows the value of Bouguer anomaly in research area around 84 mGal spreading around west-south part of research point until 279 mGal on Agung volcano body. Anomaly regional value is around 97 mGal to 253 mGal. The boundary between basement a sedimentary rock of the research area are at the depth of 0,89 km. The magma chamber of Agung volcano is in the depth of 500 to 8000 metres to a form of towing up and polluted in the middle. The density of the magma chamber is around 2,73 until 2,86 gr/cc. The magma flow in the Agung volcano of visible at the depth of 0 metres.
ANALISIS PENDUGAAN BAHAYA KEGEMPAAN DI BATUAN DASAR UNTUK WILAYAH LAMPUNG MENGGUNAKAN METODE PSHA Mhd Azri Pangaribuan; Syamsurijal Rasimeng; Karyanto Karyanto; Rudianto Rudianto
Jurnal Geofisika Eksplorasi Vol 5, No 3 (2019)
Publisher : Engineering Faculty Universitas Lampung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.23960/jge.v5i3.32

Abstract

Analysis of seismic hazard estimation is one method for estimating the effect of earthquakes. The purpose of this study was to determine the maximum value of ground acceleration in bedrock or PGA values for the Lampung Province region. This analysis of seismic hazard estimation is carried out by a probabilistic seismic hazard analysis (PSHA) method. In the process of estimating the influence of earthquakes, the PSHA method principally uses 3 types of earthquake sources, namely the source of background earthquakes, subduction earthquakes (earthquake subduction) and fault earthquakes (faut). The calculation of the estimated seismic hazard value is carried out using the 2007 USGS PSHA program. The distribution of seismic hazard values for the Lampung Province region on bedrock with a 500-year return period or a 10% probability on the PGA condition (T = 0) is 0.1 g to 1, 3 g and a 2500 year return period or a probability of 2% in the PGA condition (T = 0) is 0.1 g to 1.3 g.
ANALISIS ANOMALI SINYAL ULTRA LOW FREQUENCY BERDASARKAN DATA PENGUKURAN GEOMAGNETIK SEBAGAI INDIKATOR PREKURSOR GEMPABUMI WILAYAH LAMPUNG TAHUN 2016 Ulfa Wahyuningsih; Syamsurijal Rasimeng; Karyanto Karyanto
Jurnal Geofisika Eksplorasi Vol 4, No 2 (2018)
Publisher : Engineering Faculty Universitas Lampung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.23960/jge.v4i2.16

Abstract

Regional research had been done to analysis anomalies signal of ultra low frequency based on measurement data as an indicator of the geomagnetic earthquake precursor of lampung in 2016. To achieve purpose of the study conducted by the following steps: (i) Calculation of the total magnetic field of data; (ii) Daily Trend Analysis; (iii) the Fourier transform of the data Geomagnetic Anomaly; (iv) Localization Frequency ULF; (v) Calculation of Ratio Vertical-Horizontal (Polarization Ratio Z / H); (vi) Correction magnetic storms or Disturbance Strom Time (DST); (vii) the identification of earthquake precursors; (viii) Determination of OnsetTime, leadtime,and the direction of precursors. The results of the analysis of ten earthquakes with a magnitude above 5 MW have precursors between 11 to 30 days before an earthquake. Nine out of ten earthquakes studied had an earthquake precursors and precursors that do not have, this is because the distance is too far from the station Magdas in Liwa, West Lampung. Thus it can be seen that the precursor using the magnetic data can be used to make short-term predictions.
PREDIKSI PERMEABILITAS MENGGUNAKAN METODE LOG DAN PORE GEOMETRY STRUCTURE (PGS) PADA DAERAH CEKUNGAN JAWA BARAT UTARA Ayu Yuliani; Ordas Dewanto; Karyanto Karyanto; Ade Yogi
Jurnal Geofisika Eksplorasi Vol 6, No 1 (2020)
Publisher : Engineering Faculty Universitas Lampung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.23960/jge.v6i1.57

Abstract

Determination of reservoir rock properties is very important to be able to understand the reservoir better. One of these rock properties is permeability. Permeability is the ability of a rock to pass fluid. In this study, the calculation of permeability was carried out using log and PGS (Pore Geometry Structure) methods based on core data, logs, and CT scans. In the log method, the calculation of permeability is done by petrophysical analysis which aims to evaluate the target zone formation in the form of calculation of the distribution of shale content (effective volume), effective porosity, water saturation, and permeability. Next, the determination of porosity values from CT Scan. Performed on 2 data cores of 20 tubes, each tube was plotted as many as 15 points. The output of this stage is the CT Porosity value that will be used for the distribution of predictions of PGS permeability values. In the PGS method, rock typing is based on geological descriptions, then calculation of permeability predictions. Using these two methods, permeability can be calculated in the study area. The results of log and PGS permeability calculations that show good correlation are the results of calculation of PGS permeability. It can be seen from the data from the calculation of PGS permeability approaching a gradient of one value with R2 of 0.906, it will increasingly approach the core rock permeability value. Whereas the log permeability calculation for core rock permeability is 0.845.
PERHITUNGAN CADANGAN HIDROKARBON FORMASI TALANG AKAR MENGGUNAKAN ANALISIS PETROFISIKA DAN SEISMIK INVERSI AI DENGAN PENDEKATAN MAP ALGEBRA PADA LAPANGAN BISMA, CEKUNGAN SUMATERA SELATAN Egi Ramdhani; Ordas Dewanto; Karyanto Karyanto; Nanang Yulianto
Jurnal Geofisika Eksplorasi Vol 4, No 3 (2018)
Publisher : Engineering Faculty Universitas Lampung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.23960/jge.v4i3.37

Abstract

As a potential field in hydrocarbon prospect, Bisma field, the part of south Sumatra basin, can be evaluated in order to mapping the hydrocarbon accumulation and total reserve calculation purpose. Petrophysical analysis is an analytic method to evaluate the formation which sensitive with vertical contrast. Main output of this analysis is the compilation of some property value that useful on reservoir quality justification. Seismic acoustic impedance inversion is a method that can be used to define the distribution of porous zone as a hydrocarbon reservoir. This inversion result is the distribution of prospect area map by using combination of interpretation in AI map, density map and P-wave map. Map algebra is a calculation method that used to map that has the same grid number. By using those three methods, the reserve of hydrocarbon accumulation on Bisma field can be calculated. Petrophysical analysis results the indication of hydrocarbon in target zone is oil on two main layer, S and W3. Meanwhile, seismic inversion interpreting the distribution of porous zone is between 7400 – 9315 m/s*gr/cc in AI value context. Then, the effective porosity, Sw value and isopach are spread laterally using picked horizon and seismic acoustic impedance result as a guide, also, calculating the reserve. Layer S accumulating 21.1 million barrel oil and W3 accumulating 50.2 million barrel oil. This value resulted by aplicating Original Oil in Place (OOIP) equation on property map with map algebra approachment.
DESAIN DAN REALISASI ACCELEROMETER BERBASIS ARDUINO SEBAGAI INSTRUMEN PENDETEKSI MIKROTREMOR Ahmad Amiruddin; Suharno Suharno; Karyanto Karyanto
Jurnal Geofisika Eksplorasi Vol 5, No 3 (2019)
Publisher : Engineering Faculty Universitas Lampung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.23960/jge.v5i3.31

Abstract

To investigate soil vulnerability zones, one of the methods is microtremor analysis to analyze soil characteristics based on the natural frequency of the soil layer. However, the technology used to obtain the data is still expensive. Considering the need for this technology, this research was conducted to design a tool used as a microtremor analysis with Arduino-based accelerometer which is affordable and easier to use.  As a result, the design of the accelerometer body size is 18.5 cm x 12 cm x 7 cm with the bottom side of the box made of the iron plate as a vibration medium and the lid box is made of mica. The program system can work efficiently with a maximum sampling rate of data collection of 500/s. From the validation test, the f0 value of the HVSR curve from the accelerometer tool ranges from 0.19 Hz - 0.93 Hz. Whereas from the reference tool Reftek Accelerograph produces a range of 0.18 Hz - 0.90 Hz. The smallest difference between the two measurement tools is 0.0072 Hz at point 1 and the biggest difference is 0.1299 Hz at point 3. The average difference between the two values of f0 is 0.0377 Hz.
PERBANDINGAN NILAI PERCEPATAN TANAH MAKSIMUM BERDASARKAN MODIFIKASI KONSTANTA ATENUASI DAN DATA ACCELEROGRAPH TAHUN 2008-2016 PADA STASIUN BMKG LAMPUNG Pipit Melinda Meitawati; Bagus Sapto Mulyatno; Karyanto Karyanto; Agung Setiadi
Jurnal Geofisika Eksplorasi Vol 4, No 2 (2018)
Publisher : Engineering Faculty Universitas Lampung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.23960/jge.v4i2.17

Abstract

Peak ground acceleration is one of the parameters used in estimating the extent of breakdown caused by earthquake shocks. In the present study, the determination of an attenuation empirical formula PGA (Peak Ground Acceleration) based on the attenuation equation Lin and Wu (2010). Data used in the study of seismic event data by period year 2008-2012. Through the calculation of regression analysis, then obtained the function attenuation of peak ground acceleration in Lampung region at each station accelerograph.At the LWLI accelerograph station obtained the value of the empirical coefficient of the distance of earthquake -2.351, the empirical coefficient of earthquake magnitude 0,574, and the constant 2,430. At the KASI accelerograph station obtained the value of the empirical coefficient of the distance of earthquake -2.522, the empirical coefficient of earthquake magnitude 0.654, and the constant 2.182. At the BLSI accelerograph station obtained the value of the empirical coefficient from the distance of earthquake -3.224, the empirical coefficient of earthquake magnitude 0.651, and constant 4,092. At the KLI accelerograph station obtained the value of the empirical coefficient from the distance of earthquake -2.746, the empirical coefficient of earthquake magnitude 0.751, and the constant 2.053.Result of correlation test verification, chart relation between distance and magnitude earthquakes, ratio PGA contour maps, as well as a ratio between the value of PGA models with the observation of accelerograph year 2013-2016 show that the acceleration attenuation function of the obtained soil is relatively good. Based on PGA attenuation contour map model at an event the earthquake on 28th May 2011, PGA great value be found in the Liwa region with a PGA score of 10-20 gal and its seismic intensity value is V-VI MMI. It happens because of the source the earthquake is in the western sea of Liwa.