Udi Harmoko
Departemen Fisika, Fakultas Sains dan Matematika, Universitas Diponegoro, Semarang

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INVERSI IMPEDANSI ELASTIK UNTUK ESTIMASI KANDUNGAN RESERVOIR BATUPASIR LAPANGAN “Ve” FORMASI CIBULAKAN CEKUNGAN JAWA BARAT UTARA Aisyah, Veratania; Harmoko, Udi
YOUNGSTER PHYSICS JOURNAL Vol 1, No 1 (2012): Youngster Physics Journal Oktober 2012
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An Elastic Impedance inversion has been done for determine sandstone reservoir characterization of “Ve” Field Cibulakan Formation Northwest Java Basin. Amplitude Variation with Offset (AVO) inversion is done for determining Elastic Impedance reflectivity, near angle stack, mid angle stack, and far angle stack. Moreover Elastic Impedance inversion is done for determining Elastic Impedance volume. With DST 5 horizon for obtaining structure and slicing map to determine separating lithology of sandstone reservoir. In this research used seismic data and well data which only have a well. The step of data processing by analizing well data in order to get sensitive angle in separating lithology of sandstone and shale. Mudrock Line equation is used for this research because the available of log Vs can not reach the research target zone. Well seismic tie is done for obtaining horizon that approach the real geological zone. Initial model is made by used a control well and DST 5 horizon. From three inversion has been done Bandlimited, Sparse Spike, and Model Based inversion, Sparse Spike inversion is inversion method which gives accurate result. From that result of inversion volume is used for making slicing map intent on knowing of sandstone lithology separated. Based on analysis of Elastic Impedance inversion that content estimation of sandstone reservoir be in layer which have impedance 1348 (m/s)2gr/cc – 1365 (m/s)2gr/cc. Crossplot analysis result between log Elastic Impedance and log Gamma Ray shows that angle 350 is the best angle parameter in separating lithology of sandstone and shale. And from slicing map analysis on DST 5 horizon shows that zone distribution of sandstone reservoir have oriented north untill northeast.   Keyword: Elastic Impedance, AVO, inversion, Mudrock Line
VERTICAL TRANSVERS ISOTROPY (VTI) PRE STACK DEPTH MIGRATION ANISOTROPI UNTUK PENCITRAAN STRUKTUR BAWAH PERMUKAAN YANG LEBIH AKURAT Rasid, Ibnu; Harmoko, Udi; Setyawan, Agus; Suroso, Teguh
YOUNGSTER PHYSICS JOURNAL Vol 1, No 1 (2012): Youngster Physics Journal Oktober 2012
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Anisotropic Pre Stack Depth Migration method has been carried out for 2D seismic reflection data on Line “IR” The simplest form of anisotropic media (VTI (Vertical Transverse Isotropy) was used. Theoretically, this form requires two parameters to describe the media, those are δ (delta) and ε (epsilon). δ is an anisotropy parameter that describe velocity variation near to vertical while ε is an anisotropy parameter that describe velocity variation near to horizontal. The anisotropic Pre Stack Depth Migration produce a section which has corrected build up image and has change to be the true of reflector in 67 m of depth. Base on well and seismic data calculation process, an anisotropic parameter is in the range of 0.050-0.058. Generally, Anisotropy Pre Stack Depth Migration method gave better result than isotropy Pre Stack Depth Migration. Key Word: Anisotropy, Pre Stack Depth Migration, VTI, delta, epsilon
PENCITRAAN STRUKTUR BAWAH PERMUKAAN KOMPLEKS MENGGUNAKAN METODE PRE-STACK DEPTH MIGRATION DENGAN ALGORITMA HORIZON BASED TOMOGRAPHY PADA LAPANGAN “MF-3D” Fahmi, Muhammad; Danusaputro, Hernowo; Harmoko, Udi
YOUNGSTER PHYSICS JOURNAL Vol 1, No 1 (2012): Youngster Physics Journal Oktober 2012
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A research in “MF-3D” field under Pre Stack Depth Migration method for 3D seismic reflection data has been carried out. PSDM selected to describing to perfect subsurface structure that obtain. This research aimed to applying initial interval velocity model determination method in PSDM to obtain better imaging subsurface structure with lateral velocity variation. Initial interval velocity model determination method which used was Dix Transformation and Constrained Velocity Inversion (CVI). Velocity model is quite sufficient to determining interval velocity in shallow layer and inclined flat under Dix Transformation. However, Dix Transformation precisely obtains less sufficient and unstable interval velocity in deeper subsurface layer. CVI conducted to determining initial interval velocity model which required to obtaining better and stable interval velocity in deeper subsurface layer. Both models required to obtaining initial model of 3D seismic section in depth domain as PSDM result. That model will get correction by using Horizon Based Tomography Algorithm in further step. This research yields initial 3D interval velocity model as input for PSDM process. Key Word: Pre Stack Depth Migration (PSDM), Constrained Velocity Inversion (CVI), Horizon Based Tomography
EVALUASI MODEL KECEPATAN HASIL METODE TOMOGRAFI REFLEKSI MENGGUNAKAN ATRIBUT KINEMATIK WAVEFIELD PADA DATA SEISMIK LAPANGAN AREA JAWA TIMUR LINE “Σ01” Candra Kusuma, Galih; Suroso, Teguh; Harmoko, Udi
YOUNGSTER PHYSICS JOURNAL Vol 1, No 1 (2012): Youngster Physics Journal Oktober 2012
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A commonly used tool for the construction of such velocity models is reflection tomography by velocity analysis. One of the drawbacks of that method is, however, that it requires picking of reflection events in the seismic prestack data to provide the traveltime information for the tomographic inversion. This picking is extremely time-consuming and can become difficult or even impossible if the signal-to-noise ratio in the data is low. In this study, other tomographic inversion is presented that use of traveltime information in the form of kinematic wavefield attributes. These attributes are the coefficients of second-order traveltime approximation by coherence analysis with the common-reflection-surface (CRS) stack. The research has been carried out with real seismic data of East Java area which has been processed until pre-processing. Process is started with determining kinematic wavefield attributes. Then, the attributes is calculated to get CRS stack. Based on the CRS stack, one can determine information about normal ray travel time, spatial coordinate, first spatial travel time derivatives or slowness, and second spatial travel time derivatives. That information is reconstructed by tomographic inversion modeling to get velocity model of subsurface structure. Initial model is constructed by defining the near surface velocity and velocity gradient as a function of depth. Tomographic inversion tries to minimize the misfit between  observed data and calculated modeling data. The final model is accepted if the misfit is already reached its minimum value. Apart from the tomographic inversion with kinematic wavefield attributes, data is also processed with conventional method to get velocity model by velocity analysis. Both of the velocity models then be compared. The advantages of using tomographic inversion method is to reduce subjectivity in generating velocity model for the process carried out using a mathematical calculation. Picking is further simplified by the fact that, the pick locations do not need to follow continuous of reflector events but are independent of each other and may be placed on locally coherent events. However, if the data input that used in tomographic inversion is bad, such as in this study, then the obtained velocity model  become less precise. Whereas the conventional method, the velocity values can be directed to obtain velocity model according to most likely section. Key words : velocity model, CRS stack, reflection tomography, kinematic wavefield attributes
Analisis Velocity Model Building Pada Pre Stack Depth Migration Untuk Penggambaran Struktur Bawah Permukaan Daerah ”x” Triarto, Yose Rizal; Danusaputro, Hernowo; Harmoko, Udi
BERKALA FISIKA Vol 13, No 1 (2010): Berkala Fisika
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Pre Stack Depth Migration method has been carried out for 2D seismic reflection data on Line KPH-11807 at “X” area. This method was chosen for reconstruction geology features and imaging the subsurface structure. Based on previous investigation which done October, 2004-January, 2005, Line KPH-11807 at “X” area was a potential development as hydrocarbon prospect area which complex geology structure and strong lateral velocity variations. In the same area has been done previously with Pre Stack Time Migration by Elnusa Geosains, PT. Therefore the result of the PSDM can be compared to PSTM method. Seismic section with complex geology structure and/or strong lateral velocity variations area, which often there are at seismic data migrated stack can be overcome using an accurate velocity model. Velocity model building with the IVMB (interval velocity model building) concept consist of the coherency inversion and global tomography yield the right subsurface geological model. Hereinafter the velocity model will be used for the PSDM (pre stack depth migration) process. Result of PSDM shows a significant image enhancement, able to assure the reflection pattern at the horizons with strong lateral velocity variations and give the more coherence resolution compared with Pre Stack Time Migration seismic data. This study is very valuable in building exploration concept and development of the area, especially in a complex structure with strong lateral velocity variations.   Keywords: PSDM, velocity model building.
INVERSI IMPEDANSI ELASTIK UNTUK MENGESTIMASI KANDUNGAN RESERVOIR BATUPASIR LAPANGAN “Ve” FORMASI CIBULAKAN CEKUNGAN JAWA BARAT UTARA Aisyah, Veratania; Harmoko, Udi; Mualimin, Mualimin
BERKALA FISIKA Vol 14, No 3 (2011): Berkala Fisika
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An Elastic Impedance inversion was carried out  to determine sandstone reservoir characterization of “Ve” Field Cibulakan Formation, Northwest Java Basin. There are many steps of data processing to analize a well log data in order to get sensitive angle of lithologic characterization. Mudrock Line equation was applied to obtain Vs log data of the research target zone. The next step, we did Well seismic tie toobtain horizon that approach the real geological zone. Initial model was made by used a control well andDST 5 horizon. Sparse Spike inversion gives the most accurate result than two other one. According to thevolume inversion, we plotted to a map show the contrast of sandstone lithology. Based on Elastic Impedanceinversion analysis, we estimate the rangeof sandstone reservoir impedance:1348 (m/s)gr/cc – 1365(m/s)2gr/cc. Crossplot analysis result between log Elastic Impedance and log Gamma Ray shows that 35isthe best angle of the sandstone and shale lithologic sparation.Keyword: Elastic Impedance, AVO, inversion, Mudrock Lin
KARAKTERISASI RESERVOIR MENGGUNAKAN METODE INVERSI LAMBDA MU RHO (LMR) DAN ELASTIC IMPEDANCE PADA LAPANGAN ‘X’ Silalahi, Dian L; Harmoko, Udi; Razi, M.
YOUNGSTER PHYSICS JOURNAL Vol 2, No 4 (2013): Youngster Physics Journal Oktober 2013
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Lambda Mu Rho (LMR) inversion method has been used to diagnose the validity of the brightspot concept as the indication of the existance of hidrocarbon fluid and to find the sandstone lithology distribution of ‘X’ field with validation lithology by using the result of Elastic Impedance (EI) inversion. In fact the existance of brigthspot apparently not always be the indication of the hidrocarbon fluid and sand stone. The application of Lambda Mu Rho inversion method was able to indicates the existance of the hidrocarbon fluid and lithology well by using the incompressibility and rigidity of the rocks. The target zone was Z2260 layer with lithologies of sandstone and shale.Inversion analysis showed the distribution of fluid hidrocarbon and sandstone through indication of the low value of the incompressibility and high value of the rigidity in the target zone. The value of incompressibility dan rigidity is obtained from the data log crossplot which is then used as a reference to determine the distribution of the hidrocarbon and lithology through map inversion. To give a certain type of lithologies we made validation using the result of EI inversion which is sensitive to distinguish the lithologies.LMR inversion result showed hidrocarbon fluid distribution in layer Z2260 with Lambda Rho value 33 to  44 Mpa*gr/cc, the distribution of sandstone lithology with Mu Rho value 30 to 35 Mpa*gr/cc. The lithology was validated by the result of EI inversion which able to show the distribution of sandstone lithology in the Z2260 layer with value 8000 to 9800 (m/s)2*gr/cc. Keywords: Inversion, Lambda Mu Rho (LMR), Elastic Impedance (EI), sandstone, hidrocarbon.
KARAKTERISASI CAP ROCK DAN RESERVOIR AREA GEOTERMAL X BERDASARKAN STUDI SEISMISITAS DENGAN METODE SED Oktikawati, Anjar; Harmoko, Udi; Raharjo, Imam Baru
YOUNGSTER PHYSICS JOURNAL Vol 2, No 3 (2013): Youngster Physics Journal Juli 2013
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X geothermal area is located in the western Indonesia with high seismicity. Microearthquake (MEQ) data in geothermal exploration usually used as one of tools for approximating permeable structure in geothermal reservoirand for determining boundaries of reservoir.Five seismic recording stations recorded the earthquake in the period October 2011 to December 2011. From 34671 records data stored on the period, only 68 events microearthquake (MEQ) are inverted to obtain the hypocenter with Single Event Determination method (SED).Result inversion of the method show that permeable zone at X geothermal area is located at 10000 to 22000 X axis and 5000 to 12000 Y axis. Depth distribution shows that cap rock is located about 580 meter to 1100 meter mean sea level and the reservoir is located at altitude about 600 meter to -2000 depth. Keywords: microearthquake (MEQ), hypocenter, SED, reservoir geothe.
STUDI DISTRIBUSI TEMPERATUR PERMUKAAN DANGKAL, EMISI GAS KARBONDIOKSIDA DAN POLA ALIRAN FLUIDA UNTUK MENGKLARIFIKASI SISTEM PANAS BUMI DI DAERAH MANIFESTASI DIWAK-DEREKAN, JAWA TENGAH Nikmah, Imroatun; Harmoko, Udi
YOUNGSTER PHYSICS JOURNAL Vol 3, No 1 (2014): Youngster Physics Journal Januari 2014
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The research on temperature, carbon dioxide emissions (CO2) and fluid flow has been done at the site of geothermal manifestations Diwak-Derekan by using three methods: shallow surface temperature method, emissions of carbon dioxide (CO2) and Advance Groundwater (water level). The purpose of this study is to determine the temperature distribution, the emission of carbon dioxide (CO2) and fluid flow in the area Diwak-Derekan to get a conceptual model of the geothermal system.The shallow surface temperature measurement, emissions of carbon dioxide (CO2) and water table at the site of geothermal manifestations Diwak-Derekan has done with maps and put them in a third compiles data on height topography data.The result of study, in the manifestation area obtained result distribution of shallow surface temperature is about 30,77 oC (Diwak) and 30,64 oC (Derekan) with emission of carbon dioxide (CO2) is about 9%. And for water level measurement indicates that the flow of shallow ground water is coming from the west location of manifestations and mixed with hydrothermal fluids which then turn up to the surface as hot springs.Keywords: shallow surface temperatures, emissions of carbon dioxide (CO2), ground water, geothermal.
INTERPRETASI BAWAH PERMUKAAN SISTEM PANAS BUMI DIWAK DAN DEREKAN BERDASARKAN DATA GRAVITASI Ilmi, Syamsul; Harmoko, Udi; Widada, Sugeng
YOUNGSTER PHYSICS JOURNAL Vol 3, No 2 (2014): Youngster Physics Journal April 2014
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ABSTRACTResearch 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.Keywords: Gravity Method, 2D modelling, Diwak, Derekan