Jurnal Geofisika Eksplorasi
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INVERSI MIKROTREMOR UNTUK PROFILING KECEPATAN GELOMBANG GESER (Vs) DAN MIKOROZONASI KABUPATEN BANDUNG
Full text linkBandung Regency is a highland area with a slope between 0 - 8%, 8-15% to above 45%. The district is located at an altitude of 768 m above sea level with the northern region higher than the south. The purpose of this study was to determine the distribution of Vs30 waves and determine the impact of damage due to wave amplification (amplification). To minimize the impact of this earthquake identification can be done including a survey to map soil characteristics in response to earthquake shocks using the seismic Horizontal to Vertical Spectral Ratio (HVSR) method. Based on the results of the study, the distribution of the dominant frequency values, Bandung Regency was identified as having hard and soft rock soil and having solid clay with a thickness of tens of meters. The amplification value in Bandung Regency has a value (0 <Ao <6) which can be categorized that Bandung Regency has a small impact on the earthquake. The difference between the results of inversion processing and HVSR is due to the assumption that the layer inversion is heterogeneous and the HVSR layer is homogeneous
IDENTIFIKASI BIDANG GELINCIR PADA DAERAH RAWAN LONGSOR DESA SRIMARTANI, YOGYAKARTA
Full text linkLandslides are one of the disasters that often occur in Srimartani Village, Piyungan District, Yogyakarta. The biggest cause of landslides is the steep slope and the existence of a sliding plane on the slope. This study aims to identify the sliding plane on the slopes in Srimartani Village. This research was conducted using geoelectric method Wenner configuration with a: 10 m and n: 6. The data acquisition was taken in 6 lines. Data processing was done using Res2Dinv software and the result is a 2D true resistivity cross section. The results of the interpretation of the six lines indicate the existence of a sliding plane which is characterized by low resistivity contrast at the bottom and higher resistivity near the surface. Low resistivity (<10 Ωm) is identified as clay rock and high resistivity (> 10 Ωm) above is identified as surface soil
KLASIFIKASI PETROFISIKA TIPE BATUAN UNTUK MEMPREDIKSI KUALITAS RESERVOAR PASIR SERPIHAN PADA FORMASI TALANG AKAR, CEKUNGAN ONWJ
Full text linkHydrocarbons were accumulated in reservoir, the reservoir has a lot of types depending on the geological conditions and the constituent mineral. In ONWJ basins, sub-basins Arjuna, Talang Akar Formation is sand splintersreservoir type. The presence of clay in a reservoir will reduce the resistivity and increase thesaturation, so it takes a multimineral analysis and the reservoir qualityclassification. In this study, physical properties (porosity, permeability, Rw, and saturation) and the quality of the reservoir can be identified through petrophysical analysis by utilizing log data and core analysis, and the rocktypeprediction(using R35 Winland or HFU method). In this study 5 wells (IX-A1, IX-13, IX-4, IX-7 and IX-8)used and found eight hydrocarbon zones, 6 are validated by the DST (drill steam test)data, androck type method that suitable is the method of HFU (hydraulic flow units) due to the coefficient of correlation between porosity and permeability shows a value of > 0.75, based on the calculations, the eight types of rock is conclude, where the dominance of the rock typeis the type 12 with a pore size between 5-10 microns, type reservoir rocks in this study belong to the lithofacies distributary channel and mouthbar sand. By knowing the petrophysical property values, it can determine reservoir productivity and determine the zone eligible to be produced or not, by using curve SMLP (Stratigraphic Modified Lorenz Plot)
PREDIKSI PERMEABILITAS MENGGUNAKAN METODE LOG DAN PORE GEOMETRY STRUCTURE (PGS) PADA DAERAH CEKUNGAN JAWA BARAT UTARA
No full textDetermination 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
ANALISIS SIFAT FISIS PADA RESERVOAR BATUPASIR MENGGUNAKAN METODE SEISMIK INVERSI IMPEDANSI AKUSTIK (AI) DAN MULTIATRIBUT PADA LAPANGAN “MNF†CEKUNGAN BONAPARTE
Full text linkAnalysis of the physical properties of the sandstone reservoir in this study was carried out using the acoustic impedance inversion method and seismic multi-attribute which was carried out at the Bonaparte Basin "MNF" Field. In this study, the acoustic impedance distribution is generated, and the acoustic impedance is derived to obtain a water saturation distribution map and the volume of the log property is predicted to predict pseudo gamma ray, density and porosity with multi-attribute analysis using linear regression method with step wise regression technique. From the results of well data crossplot analysis for sand-shale sensitivity analysis and inversion analysis on sandstones filled with hydrocarbon fluid obtained the acoustic impedance value is between 12,000 ft / s * g / cc - 27,000 ft / s*g / cc. In the Middle part around the NN-1, NN-3 and NN4 wells and the Southeastern part of the research area are prospect areas that have gamma ray values with a range of 5-70 API, density with a range of 2.1-2.3 gr / cc and porosity with a range of 18-23% and SW of 10-13% indicating that the hydrocarbon gas accumulated in the research field. The results of the multi-attributes and acoustic impedance show that the sandstones in this field are thight sandstones
ANALISIS RESERVOAR MIGAS (SANDSTONE) MENGGUNAKAN MULTIATRIBUT SEISMIK PADA LAPANGAN TG12, CEKUNGAN BARITO, KALIMANTAN SELATAN
Full text linkThe study using multi attribute seismic has been done on TG12 field which situated at Lower Foreland Formation, Barito Basin dominated by sandstone on layer area of the target X. The objective of the study is to map the sandstone reservoir by predict distribution value of gamma ray log, neutron porosity, and density which goes through wells such as FM1, FM2, FM3, and FM4 on seismic data. Total attribute that is being used by step wise regression method by considering validation error. Multiattribute process only applied on FM2, FM3, and FM4 wells, whereas FM1 is used as a test well to determine the correlation value between seismic data and log data that is being used. In addition, from well test correlation showing great correlation result of neutron porosity log and density log both obtain the correlation around 0.6322 and 0.6557 while the gamma ray log obtain low correlation that is 0.1647 towards multi attribute result. The processing result of multi attribute obtained distribution of sandstone with gamma ray estimation range value of 65-75.8API, neutron porosity estimation range value 0.15-0.2262, while density estimation range value 2.4308-2.77gr/cc
PERHITUNGAN CADANGAN HIDROKARBON FORMASI TALANG AKAR MENGGUNAKAN ANALISIS PETROFISIKA DAN SEISMIK INVERSI AI DENGAN PENDEKATAN MAP ALGEBRA PADA LAPANGAN BISMA, CEKUNGAN SUMATERA SELATAN
Full text linkAs 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
3D DATA GRAVITY MODELING FOR IDENTIFICATION OF THE FORMATION STRUCTURE OF THE HYDROCARBON BASIN IN THE BAJUBANG REGION, JAMBI PROVINCE
Full text linkJambi is an area that has natural resources in the form of petroleum, one of which is the Bajubang region. Bajubang is located in the Jambi Sub Basin where ripe hydrocarbons are visible in the Talang Akar Formation. Petroleum exploration continues to run out of oil reserves. To find the presence of a sedimentary basin that has stopped, it can be done by measuring the gravity method. The basic concept of this method is to measure the geographical variation of an area on the earth's surface and corrected through the prevailing measurements or prices. The purpose of this research is to determine the geological structure pattern that causes the formation of sub-basins that indicate the presence of hydrocarbons and describe the subsurface conditions using forward modeling and backward modeling. Based on the modeling results found as many as 7 sub basins sediment. The height and fault structures are identified in the subsurface model. Based on the regional anomaly map shows the presence between the basin and the elevation. The fault structure, anticline and sub-basins are found which are expected to produce hydrocarbons
PENGHILANGAN SWELL NOISE DAN LINIER NOISE PADA DATA SEISMIK 2D MARINE HIGH RESOLUTION PADA LINTASAN “AF†MENGGUNAKAN METODE SWNA, F-K FILTER DAN TAU-P TRANSFORM
Full text linkoai:ojs2.jge.eng.unila.ac.id:article/3Research have been done about noise removal caused by environment (swell noise) and linear noise on high frequency 2D seismic data on line “AF†using swell noise attenuation (SWNA) method, f-k filter and tau-p transformation. Based on obtained result, swell noise succeed removed from data using velocity limited filter that is 1000 m/s on frequency 25 Hz applied to swell noise attenuation process. Applied SWNA data, then created input f-k filter process. In f-k filter process, used polygon design having a minimum frequency limit around 5 Hz maximum high frequency around 450 Hz. The results f-k filter giving a good output with linear noise removal to time 1500 ms. F-k filter output obtained, then processed again using tau-p transformation method. Application of tau-p transformation transformed data into (τ-p) domain. Transformed data on (τ-p) domain, linear noise made on moveout 600 ms. Then the data muted using surgical mute. Based on obtained result, tau-p result can removing linear noise on data. Linear noise removed dominating on time 1500 ms-2500 ms. That matter caused by linear noise on time 0-1500 ms succeed removed using previous process. After the method succesfully applied , data processing continued doing the stack and migration process. Applied migration is postack kirchoff time migration, migration do with migration angel around 300 and aperture around 600 m
OPTIMALISASI DAN ANALISIS DESAIN PARAMETER SEISMIK 3D DARAT BERDASARKAN MODEL GEOLOGI LAPANGAN “RLâ€
No full textThe design of 3D land seismic parameters is a preliminary step before the acquisition of 3D land seismic data to obtain seismic data quality and efficient survey budget. The objective of this research is to obtain high quality of 3D land seismic data based on fold coverage spread on each target layer. The method used is based on the principle of wave propagation or ray tracing method on each target layer, wherein each wave reflection point (bin) will have a different value of fold so that the required configuration of the stretch that will result in the optimal spread of the fold. The applied stretch configurations are orthogonal, brick, zig-zag and slanted where each stretch configuration uses two types of templates that is narrow and wide azimuth. From the simulation analysis results of several stretch configurations in the survey area, then the optimal stretch configuration will be obtained in the survey area. The stretch configuration will be applied is the configuration of orthogonal stretch with narrow azimuth type template. Consideration of the selection of this stretch configuration because it has a more evenly folding effect on the target layer than with other stretch configurations. Furthermore, to obtain the configuration of the appropriate stretch of field conditions, the source point is moved outside the obstacle zone so that the quality of seismic data is maintained