Hasil Pencarian  ::  Simpan CSV :: Kembali

"Formasi Keutapang yang berada pada Cekungan Sumatera Utara merupakan salah satu cekungan back-arc di Indonesia yang sudah memproduksi minyak dan gas. Dalam penelitian ini, formasi Keutapang didominasi oleh litologi perselingan batupasir dan batuserpih. Metode Continuous Wavelet Transform (CWT) dan metode atribut RMS Amplitude digunakan untuk pemetaan reservoir batupasir karena dapat memetakan lapisan tipis dan efektif terhadap perubahan kontras amplitude. Hasil dari penerapan (CWT) pada frekuensi 30 Hz dapat memetakan dengan baik kemenerusan lapisan batupasir pada Formasi Keutapang. Untuk hasil analisa atribut RMS Amplitude dengan jendela 20 ms dapat memetakan sebaran batupasir dengan baik. Respon RMS Amplitude tinggi merupakan batupasir sedangkan untuk batuserpih ditunjukkan dengan daerah RMS Amplitude rendah. Interpretasi distribusi reservoar batupasir dari (CWT) dan atribut RMS Amplitude dihasilkan sebagai pengendapan channel.

---

Keutapang Formation located in North Sumatera basin is one of the back arc basin in Indonesia which has produced oil and gas. In this research, Keutapang formation dominated by sandstone and shale lithology. Continuous Wavelet Transform (CWT) and RMS Amplitude attribute method used for sandstone reservoir mapping because it can map out a thin layer and effective to amplitude contrast changing.

The result of (CWT) apllication in 30 Hz frequency could map well on the sandstone layer continuity in Keutapang Formation. For RMS amplitude attribute analysis result with 20 ms window can map out the distribution of sandstone well. High amplitude RMS response is sandstone while shale showed by Low Amplitude RMS area. The interpretation of sandstone reservoir distribution of and RMS Amplitude attribute generated as the channel sedimentation."

"Lapangan Salemba dan Depok adalah lapangan gas yang berada di daerah Selat Madura. Pada dua sumur eksplorasi telah ditemukan akumulasi hidrokarbon gas pada Formasi Lidah yang berumur Plio-Pleistocene. Formasi Lidah didaerah studi ini diinterpretasikan sebagai sistem pengendapan channel. Permasalahan yang muncul dalam menganalisa data seismik untuk mengetahui geometri dari channel sendiri adalah adanya lapisan tipis yang tidak terdeteksi dan batas kontinuitas pelapisan yang kurang jelas. Oleh karena itu, diperlukan metode yang lebih baik untuk analisa data seismik agar masalah tersebut dapat diatasi.Dalam tesis ini, analisa data seismik metode dekomposisi spektral dengan algoritma Continuous Wavelet Transform (CWT) digunakan karena hasilnya dapat memberikan gambaran yang lebih baik dalam penyebaran ketebalan dan diskontinuitas geologi. Selain itu juga digunakan metode inversi seismik untuk mengetahui penyebaran impedansi akustik yang merupakan sifat fisis batuan.Hasil studi ini menunjukkan bahwa metode dekomposisi spektral dan inversi seismik telah berhasil membantu dalam mendeliniasi geometri channel Formasi Lidah. Penampang dekomposisi spektral merepresentasikan ketebalan dan diskontuniuitas geologi dari reservoir batupasir Formasi Lidah. Distribusi frekuensi pada reservoir direpresentasikan pada nilai frekuensi 10, 20, dan 30 Hz. Pada inversi seismik, penampang impedansi akustik merepresentasikan litologi bawah permukaan. Distribusi impedansi akustik pada reservoir mempunyai nilai rata-rata 15000 - 19700 ((ft/s)*(g/cc)), sedangkan pada non-reservoir mempunyai nilai impedansi akustik lebih dari 19700 ((ft/s)*(g/cc)).

---

Salemba and Depok fields are a gas field which located in the Madura Strait. Two exploration wells have been discovered hydrocarbons accumulation of gas in the Lidah Formation aged Plio-Pleistocene. Lidah Formation in the study area was interpreted as channel depositional environment. The problem that then arises in analyzing seismic data to predict the channel geometry is undetected thin layer and unclear reservoir continuity. Therefore, the better method to analyze the seismic data is needed to solve the problem.

In this thesis, seismic data analysis spectral decomposition method with Continuous Wavelet Transform (CWT) is used because the results can provide a better map of the thickness distribution and geological discontinuities. This thesis is also used seismic inversion method to know the acoustic impedance distribution as the physical properties of rocks.

The result of this study shows that the spectral decomposition method and seismic inversion has helped to delineate the channel geometry of Lidah Formation. The section of spectral decomposition represents thickness and geological discontinuity in Lidah Formation. Frequency distribution in the reservoir has an average of 10, 20, and 30 Hz. In the seismic inversion, the section of acoustic impedance represents the subsurface lithology. Acoustic impedance distribution in the reservoir has an average of 15,000 - 19,700 ((ft/s)*(g/cc)), whereas in nonreservoir having an acoustic impedance more than 19,700 ((ft/s)*(g/cc))."

"ABSTRAKPada studi ini dilakukan evaluasi daerah prospek penyebaran hidrokarbonmenggunakan metode dekomposisi spektral CWT dan inversi Seismik yangdiintegrasikan untuk mendelineasi daerah prospek hidrokarbon. Studi kasusdilakukan pada daerah prospek ”XYZ” cekungan Sumatra Selatan dengan targetreservoir formasi Baturaja dengan kedalaman 400m - 1650 m. Studi inimenggunakan data Seismik 2D dan dua data sumuran (sumur B dan sumur C). Daridata Log sumuran yang tersedia, sumur B menunjukkan kosong (dry) namun padaformasi Baturaja terlihat Oil Show pada kedalaman 1500 m – 1600 m. Sedangkansumur C menunjukkan kosong dan memperlihatkan bahwa formasi Baturaja tidakberkembang dengan baik. Hasil studi menunjukkan bahwa metode spektraldekomposisi CWT mampu memperlihatkan konsistensi anomali hidrokarbon padafrekuensi rendah hanya pada sumur B. Hal ini sejalan dengan dugaan adanyakeberadaan hidrokarbon pada sumur B. Lebih lanjut hasil metode inversimemperlihatkan kemenerusan reservoir formasi Baturaja ke arah barat laut padadaerah studi. Nilai acoustic impedance formasi Baturaja berada pada kisaran 9000 –11000 m/s * gr/cc. Hasil integrasi inversi Seismik dan analisa dekomposisi spektralmemberikan gambaran zona prospek penyebaran hidrokarbon.

---

ABSTRACTThis study evaluates the hydrocarbon prospect area deployment using CWT spectraldecomposition method and the integrated Seismic inversion to delineate areas ofhydrocarbon prospects. Case studies conducted in the South Sumatra basin “XYZ”prospect area with the target Baturaja Formation with a depth of 400 m - 1650 m.This study uses 2D Seismic and two data wells (well B and well C). From availablewell log data, well B shows empty (dry) but indicate oil show on the Baturajaformation at a depth of 1500 m - 1600 m, whereas well C shows empty wells andshow Baturaja formations not developed well. The study results showed that themethod of spectral decomposition CWT is able to demonstrate the consistency ofanomalous hydrocarbons at low frequencies only in well B. This is consistent withthe allegations of the presence of hydrocarbons in the well B. Further resultsInversion method shows Baturaja reservoir formations continuity to the northwest inthe study area. Baturaja formations acoustic impedance values in the range of 9000 –11000 m/s*gr/cc. The result of the integration of Seismic Inversion and spectraldecomposition analysis give an overview of deployment of hydrocarbon zoneprospects."

"Penelitian ini melakukan identifikasi lapisan shale gas menggunakan Inversi Impedansi Akustik dan Dekomposisi Spektral. Penelitian dilakukan di Lapangan "AP", Cekungan Barito dan formasi target yaitu Formasi Tanjung. Nilai Total Organic Carbon (TOC) ditentukan dengan menggunakan Passey's Number dan data geokimia. Selanjutnya, zona shale gas ditentukan dengan mengorelasikan Log Gamma-ray dengan Log Densitas, Sonic, NPHI, dan Resistivitas pada dua sumur. Hasil korelasi menunjukkan terdapat zona shale gas pada masing-masing sumur, yaitu dikedalaman 7130-7370 ft (Sumur A-1) dan 3100-3280 ft (Sumur P-1). Zona shale gas Sumur A-1 dan Sumur P-1 memiliki TOC rata-rata 5.4 wt% dan 2.8 wt%. Hasil tersebut didukung oleh hasil inversi impedansi akustik (AI) yang menujukkan nilai impedansi rendah untuk zona shale gas antara 5000-8000 m/s*g/cc (Line A-1), dan 7200-8900 m/s*g/cc (Line P-1). Selain itu, hasil tersebut juga didukung oleh hasil dekomposisi spektral yang menunjukkan anomali Continuous Wavelet Transform (CWT) tinggi pada frekuensi 18 Hz (untuk Line A-1) dan 20 Hz (untuk Line P-1). Analisis terintegrasi antara data seismik, hasil inversi AI dan CWT menunjukkan terdapat daerah potensial shale gas pada punggungan antilkin di Line A-1 dan Line P-1.

---

This study identify shale gas layer using acoustic impedance (AI) and spectral decomposition. The object of this study is Field ‘AP’, Barito Basin, and the formation target is Tanjung Formation. Total Organic Carbon (TOC) values was determined using Passey’s Number and geochemical data. Furthermore, shale gas zone was determined by correlating Gamma-ray log with Density, Sonic, NPHI and Resistivity log in two wells.

Correlation result showed there are a shale gas zone in each well, which is at 7130-7370 ft (Well A-1) and 3100-3280 ft (Well P-1). Shale gas zone Well A-1 and P-1 has average TOC of 5.4 wt% and 2.8 wt%. These results are supported by calculation of AI inversion, which showed a low impedance values for shale gas zone between 5000-8000 m/s*gr/cc (Line A-1) and 7200-8900 m/s*gr/cc (Line P-1).

Besides, spectral decomposition also showed high CWT anomaly at 18 Hz (Line A-1) and 20 Hz (Line P-1). Integrated analysis of seismic data, AI, and CWT indicates there are potentials area of shale gas on the anticline ridge on Line A-1 and Line P-1."

"A detailed combined geological and geophysical study in North Sumatra basin has shown that prospective formations for shale play containing gas sweet spots are found to be shales from Bampo, Belumai, and Baong Formations. Bampo Formations Exhibits low shale gas potential with very low to medium in organic material contents, maturity index of immature to mature, and moderate brittleness. Rocks within the formation tent to be reactive to highly reactive to water, with a moderate degree of swelling capacity. Porosity varies within 5.8-7.4% with permeability raging from 0.37 to 3.2 mD. Sweet spots in the formation found around Basilam-l and Securai-l wells occupy about 21% of the formation. On the other hand, Belumai Formation shows moderate to good shale gas potential, with low to high organic material contents, immature to mature levels of maturity, and moderately brittle to brittle. Sweet spots areas in the formation fpund around the two wells are about 29% of the formation. For Baong Formation, analysis reveals moderate to good shale gas potential, with low to medium contents of organic material, immature to mature in maturity index, moderately brittle to brittle in brittleness, and tendency of being reactive to highly reactive to water but with low degree of swelling capacity. Sweet spots in the formation found around two wells occupies are roughly 11% of the total formation volume in the area. Basin modeling leading to gas resources estimation for Baong, Belumai, and Bampo Formations has led to estimated volumes of 6, 379 TCF, 16, 994 TCF, and 25,024 TCF, respectively, with a total amount of 48, 397 TCF. The resources figures are speculative in nature and do not incorporate any certainty and efficiency factors."