Data validation of gravity field and satellite data using correlation and coherence method

Satellite data is frequently used as an initial study of a research area for its easy to access feature as well as its improving quality. One of the available satellite data is geopotential data. Satellite data is commonly used to be correlated to the topography data. In this research, satellite data is used as the database of validation in a research area. Valid measuring data is highly required, so that the qualified data is obtained for further process. To identify the validity, additional other QC is required than the existing QC which in 1D. The validation method which applied are correlation and coherence method. The distribution of correlation and coherence values show  asimilirity or compatibility of field data with satellite data. The correlation method was calculate in 2D and the coherence in 1D. Correlation calculation of field data produces high correlation and coherence value to satellite data as much as 0.7 to 0.95 so that it could be identified that acquisition and data processing have been carried out correctly

Inversi Impedansi Akustik Seismik 3D Untuk Estimasi Porositas Batuan (Studi Kasus Lapangan X Cirebon)

Telah dilakukan inversi impedansi akustik pada data seismik 3D time migrated amplitude preserved stack dengan kontrol data log sumur pada lapangan X Cirebon. Metode yang digunakan adalah constraint sparse-spike in eigenvalue basis yang bertujuan mengestimasi porositas reservoar dari impedansi akustik di lapangan X Cirebon. Sebagai data input proses inversi wavelet dari fase residual seismik 3D dibandingkan dengan wavelet seismogram sintetik pada tiap lokasi sumur. Model awal inversi yang diperoleh dari 8 data log sumur diinterpolasi dengan metode kriging. Impedansi akustik hasil inversi selanjutnya dibuat model garis regresi linear kuadrat minimum terhadap log porositas sumur AL-03. Persamaan yang diperoleh digunakan untuk mengestimasi nilai porositas berdasarkan nilai impedansi akustik reservoar. Dari hasil inversi impedansi akustik yang dilakukan diperoleh tiga zona impedansi akustik di area penelitian. Nilai impedansi akustik untuk lapisan yang diduga merupakan lapisan reservoir memiliki nilai impedansi relatif rendah dibanding sekitarnya yaitu berkisar antara (1500 – 6500) ´103kg/m2s yang berada pada twt 940 ms sampai 1010 ms, dengan porositas berkisar antara 18% sampai 34%

Penentuan Kedalaman dan Ketebalan Akuifer Menggunakan Metode Seismik Bias (Studi Kasus Endapan Alluvial Daerah Sioux Park, Rapid Creek, South Dakota, United State of America)

Data processing of refraction Seismic has been done by using the secondary data in area of Sioux Park, Rapid Creek, South Dakota, United State of America with the trajectory of seismic SP#1 which has geology structure of alluvial sediment. The sediment Alluvial has a form of water carrier rock precipitated by Rapid Creek Tthe data processing of refraction Seismic usedin this experiment is Reciprocal Hawkins methode that represent a method that develop concept of time depth recognition. The time Depth from the refractor is equal for the travel of critical time from the aspect of between refractor and surface less than time required for the ray path of projection of area refractor at a speed of refractor. Results of the seismic refracted obtained: first layer consist of clay functioning as covering laye, the second layer lapped over from clay, sand, and gravel functioning as carrier coat irrigate or coat acquife and the third layer lapped over from stone napal, functioning as waterproof coat ( impermeable). Deepness of layer acquifer vary from 0.93 ft - 12.01 ft ( 0.28 m – 3.66 m), and their thickness vary from 0.86 ft – 14.43 ft ( 0.26 m – 4.40 m). The geometry of these acquiferare in the form of free acquifer or unconfined aquifer

ESTIMASI HUBUNGAN POROSITAS DAN PERMEABILITAS PADA BATUPASIR (Study kasus FORMASI KEREK, LEDOK,SELOREJO)

The research to know the relation of porosity and permeability on sandstone from Kerek, Ledok, and Selorejo formation is carried out. Permeability is measured using Ruska Gas Permeameter, and the porosity is measured using Helium Porosimeter. The relation between porosity and permeability on sandstone taken by linear regretion method. The result of linear corellation analysis shows that there is a positive relation between porosity and permeability on sandstone samples. Data was processed by using linear regression and the result is log k = 0,06f + 0,34 with r= 0,95. where k in mD and f in percent

PEMETAAN SEBARAN AIR TANAH ASIN PADA AQUIFER DALAM DI WILAYAH SEMARANG BAWAH

A research to mapping of saline groundwater spreading at deep aquifer in SEMARANG Awash area, exactly at 49 zone, coordinate X(422000-445000), Y(9222100-9232000) is carry out. Electrical conductivity used in this research as approximation to saline value of groundwater. Then, the isoconductivity contour map made based on that’s conductivity value using surfer 7 to see the mapping of saline groundwater spreading. After that, a hydrochemistry analyze method resemble to Trilinier Piper diagram and Chlorida-Carbonat Ratio (R) used to analyze caused factor of saline from groundwater. Base on the groundwater saline grade clasification from PAHIAA, Jakarta, the groundwater at deep aquifer of Semarang bawah area come in insipid that spread out almost in all Semarang bawah area and insipid-saltish groundwater clasification that just found in two area, are central Pedurungan (Tlogosari) and Tugu Muda direct to Pemuda street area. Base on Trilinier Piper diagram and Chlorida-Carbonat Ratio (R) analyze, the saline of groundwater at deep aquifer in Semarang Awash area is the effect from the sea water intrusio, except in central Semarang area the salted of groundwater it’s not caused by the sea water intrution, may be couse by dilution of salt mineral which imbedded in the groundwater.

ANALISIS ATRIBUT SEISMIK UNTUK IDENTIFIKASI POTENSI HIDROKARBON(Studi kasus daerah Amandah, Formasi Talangakar, Cekungan Jawa Barat Utara)

Rms amplitude and spectral decomposition attribute have been extracted for hydrocarbon potential identification in Amandah area, Talangakar Formation, North West Java Basin. Purpose of rms amplitude extractions is to see the change of lithology which is extreme. Example is like reservoir existence. Spectral decomposition has been used to see reservoir at thin thickness. The seismic attributes has been extracted from seismic data 3D Pre Stack Time Migration (PSTM). Log data has been taken from a well (AMD-01) to interpret and determine reservoir thickness in interest zone. Seismic attribute analysis has been used to see existence and shape of channel’s geometry spreading. The result of rms amplitude attribute extraction is reservoir which can be detected clearly at 10 ms, 20 ms, 30 ms and 40 ms window analysis. Whereas the result of spectral decomposition attribute extraction is reservoir which can be detected at 15 Hz – 25 Hz frequency with 30 ms and 40 ms window analysis. The result of rms amplitude and spectral decomposition attribute analysis shows hydrocarbon in Amandah area, Talangakar Formation is potential in channel depositional facies with depositional direction at north-south (N-S) and north nort east – south south west (NNE-SSW) and thickness high of channel is concern at 36-60 m

PEMODELAN TOMOGRAFI CROSS-HOLE METODE GEOLISTRIK RESISTIVITAS (Bentuk Anomali Silindris)

Cross-hole method using an amount of electrode were placed downhole is one of tomography method. Cross-hole tomography method delineate the geological conditions of the earth surface therefore it takes an important rule in the case of anomaly monitoring. The buis concrete planted in subsurface with deepness of about 1 m were used as the source of anomaly. Tomography cross-hole data with configuration such as pole-pole, pole-bipole, bipole-pole and bipole-bipole array were taken with the depth of the borehole is 1,2 m. The space variation of one electrode to another in the hole of drill is 0,2 m, 0,4 m, 0,6 m and 0,8 m for the configuration of pole-bipole, bipole-pole and bipolebipole. Res2Dinv program obtained the images of bipole-bipole better than the images of other configuration. While the pole-pole configuration had the worst images compared to others. It is caused by two remote electrode of pole-pole array while bipole-bipole array do not have ones

INTERPRETASI BAWAH PERMUKAAN DENGAN METODE SELF POTENTIAL DAERAH BLEDUG KUWU KRADENAN GROBOGAN

The geophysics research to observe the subsurface anomaly in Bledug Kuwu had been done. It was used to analyze and interpret the potential data. The purpose of this research was to interpret the object of subsurface anomaly. The research was used self potential method with base point electrode configuration. Data processed used Surfer 8 software, which result was an isopotential contour map. The modeling processed used curve matching for a spherical model. By using Bhattacharya theory, the depth and polarization angle was founded as the parameter of a spherical model. The research’s result of the depth of anomaly origin is 19,5 m, 23,68m, and 40,8 m. The polarization angle is 70o, 70,38o and 100o

Analysis of Seawater Intrusion Based on Conductivity Method and Hydro-Chemical Approaches to Shallow Coastal Wells in Alluvial Plains of Kendal Regency, Central Java

<p><i>Kendal Regency is one of the regencies in Central Java which has 0.64% of population growth and 1.023/km2 of population density per year. Kendal Regency is also known as Industrial Area. On other hand, Regional Drinking Water Company (PDAM) has increased in demand every year, and mostly being used for household needs. These indicates that there is less surface water supply in Kendal Regency. As a result, there are negative effects such as lowering the ground water level, decreasing the quantity and quality of ground water, and seawater intrusion. This research was made to determine the distribution of seawater intrusion in the coastal areas of Kendal Regency. The method used in this research was to find the value of Electrical Conductivity in well water. And then, the well water was tested using hydro-chemical test to determined the cause of intrusion in the research area by projecting on the Trilinear Piper diagram. This research was conducted in 7 districts in Kendal Regency which are located in 38 shallow well points in coastal area. The result shows that the values of Electrical Conductivity have range of 436 μS/cm to 5.083 μS/cm. based on these results, the well water in this research area can be classified into fresh water, fresh-brackish water, and brackish water. The analysis using Trilinear Piper diagram can be concluded that the saltiness of the well water in the research area are occurred due to seawater intrusion.</i></p&gt

Subsurface Interpretation of the Sembalun Area, East Lombok using the Gravity Method

<p><i><strong>The Sembalun area in UTM coordinates is located atEast hanging 452120,3 to 437998,9 and Northing 9062924 to 9085495 and belongs to the UTM 50S zone which is located on Lombok Island, West Nusa Tenggara. The purpose of this study is to determine the presence of subsurface geological structures in the Sembalun area, East Lombok. The geophysical method used in this research is method gravity namely by finding the distribution of density values and finding values Complete Bouguer Anomaly (CBA) which will be used to perform 2D modeling of subsurface geological structures in the study area using software Grablox. The data used in this research is secondary data in the form of GGMplus 2013 satellite imagery data gravity disturbance and Earth Residual Terrain Model (ERTM2160). The results obtained from this study include the rock density obtained by the parasnis method of 2.815 g/cm3. The fault structure is in the North to Southwest of the study area and there is also a caldera in the middle of the study area (between Sembalun Bumbung and Sembalun Lawang). Manifestations in the form of hot springs are in the south (close to Mount Pusuk). The results of 2D modeling with Grablox are dominant with high density indicating that the study area is dominated by andesitic lava rock.</strong></i></p&gt