Wibowo, Ramadhana Millenio Olka (2022) Analisis Sub-Cekungan Dan Potensi Hidrokarbon Berdasarkan Pemodelan Gaya Berat Serta Inversi Acoustic Impedance (AI) Data Seismik Pada Cekungan Nias. Other thesis, Institut Teknologi Sepuluh Nopember.
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Abstract
Perkembangan teknik interpretasi membuka peluang baru dalam eksplorasi migas pada cekungan fore-arc bagian barat Indonesia. Termasuk diantaranya wilayah Cekungan Nias dengan indikator penemuan rembesan minyak dan gas. Studi Cekungan Nias dilakukan berdasarkan analisis dan pemodelan gayaberat serta inversi seismik dengan tujuan mengetahui gambaran umum bawah permukaan, pola penyebaran sub-cekungan sedimen, dan keberadaan potensi hidrokarbon. Pemrosesan data gayaberat Complete Bouguer Anomaly (CBA) dilakukan dengan Teknik analisis spektral untuk mengetahui kedalaman anomali serta lebar window yang digunakan sebagai input untuk pemisahan anomali. Filter yang digunakan adalah high-pass dan low-pass dengan keluaran berupa anomali regional dan residual. Struktur bawah permukaan diperoleh berdasarkan interpretasi kuantitatif pemodelan kedepan dari anomali residual menggunakan perangkat lunak Oasis Montaj. Interpretasi data seismik dan sumuran menggunakan perangkat lunak Hampson Russell. Tahapan pengolahan data seismik dan sumur meliputi analisis sensitivitas untuk mengetahui perbedaan litologi pada sumur, well seismic tie untuk menyamakan kedalaman sumur dan data seismik, picking horizon untuk mengetahui kemenerusan lapisan dari amplitudo seismik, serta inversi acoustic impedance (AI). Berdasarkan hasil anomali residual ditemukan 8 pola sub-cekungan sedimen yang tersebar pada area penelitian dan memiliki arah kemenerusan relatif barat laut – tenggara mengikuti pola kelurusan tinggian yang terbentuk di area Cekungan Nias. Hasil pemodelan kedepan diperoleh 4 lapisan formasi batuan yang secara berurutan dari basement berupa batuan dasar metamorfik dengan densitas 2,7 gr/cc, Formasi Lelematua dengan densitas 2,5 gr/cc, Formasi Gomo dengan densitas 2,4 gr/cc, dan Formasi Gunungsitoli serta lapisan alluvium dengan densitas 2,25 gr/cc. Interpretasi data sumur dan seismik menunjukkan zona target pada kedalaman 2017 – 2101 m. Hasil inversi AI menggunakan Model Based Hard Constraint pada zona target mengungkap potensi hidrokarbon Cekungan Nias yang diperkirakan berada pada batuan tight carbonate berupa batugamping anggota Formasi Gomo. Nilai cutoff AI diketahui tergolong tinggi > 34000 (ft/s)*(g/cc) berdasarkan analisis sensitivitas dengan interval 34000 – 47000 (ft/s)*(g/cc).
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The development of interpretation techniques opens up new opportunities in oil and gas exploration in the fore-arc basins of western Indonesia. This includes the Nias Basin area with indicators of the discovery of oil and gas seepage. The study of the Nias Basin was carried out based on analysis and modeling of gravity and seismic inversion with the aim of knowing the general description of the subsurface, distribution of sedimentary sub-basins, and the presence of potential hydrocarbons. Complete Bouguer Anomaly (CBA) gravity data processing is carried out using spectral analysis techniques to determine the depth of the anomaly and the width of the window that is used as input for the separation of anomalies. The filters used are high-pass and low-pass with the output in the form of regional and residual anomalies. The subsurface structure was obtained by quantitative interpretation of forward modeling of the residual anomaly using Oasis Montaj software. Seismic and well data interpretation using Hampson Russell software. The proccess of the seismic and well data include sensitivity analysis to determine lithology differences in wells, well seismic tie to equalize well depth and seismic data, picking horizon to determine layer continuity from seismic amplitude, and acoustic impedance (AI) inversion. Based on the results of the residual anomaly, 8 sedimentary sub-basin patterns were found scattered in the study area and have a relatively northwest-southeast direction following the pattern of high lineaments formed in the Nias Basin area. The forward modeling results obtained 4 layers of rock formations sequentially from the basement in the form of metamorphic bedrock with a density of 2.7 gr/cc, the Lelematua Formation with a density of 2.5 gr/cc, the Gomo Formation with a density of 2.4 gr/cc, and the Gunungsitoli and alluvium layer with a density of 2.25 g/cc. The interpretation of the well and seismic data shows the target zone at a depth around 2017 – 2101 m. The results of the AI inversion using a Model Based Hard Constraint in the target zone reveal the hydrocarbon potential of the Nias Basin which is estimated to be located in tight carbonate rocks in the form of limestone members of the Gomo Formation. The AI cutoff value is known to be high > 34000 (ft/s)*(g/cc) based on sensitivity analysis with interval 34000 – 47000 (ft/s)*(g/cc).
| Item Type: | Thesis (Other) |
|---|---|
| Additional Information: | RSGf 551.22 Wib p-1 2022 |
| Uncontrolled Keywords: | Cekungan Nias, Pemodelan Kedepan Gayaberat, Inversi Acoustic Impedance (AI), Tight Carbonate. Nias Basin, Forward Modeling Gravity, Acoustic Impedance (AI) Inversion, Tight Carbonate. |
| Subjects: | Q Science > QE Geology > QE538.8 Earthquakes. Seismology |
| Divisions: | Faculty of Civil, Planning, and Geo Engineering (CIVPLAN) > Geophysics Engineering > 33201-(S1) Undergraduate Thesis |
| Depositing User: | Mr. Marsudiyana - |
| Date Deposited: | 21 May 2026 04:07 |
| Last Modified: | 21 May 2026 04:07 |
| URI: | http://repository.its.ac.id/id/eprint/133301 |
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