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Abstrak :
Pada lapangan Meranji terdapat tiga sumur yang ketiganya menembus formasi Namur, tetapi hanya sumur Meranji-1 yang mengalirkan hidrokarbon minyak dari formasi Namur. Kebutuhan mengenai informasi geologi regional menjadi dasar atau batasan berpikir penulis sekaligus acuan dalam memetakan persebaran fasies pada lapangan ini. Sebagai dasar dalam pembuatan model properti batuan, perkembangan fasies perlu diketahui secara rinci dengan menggunakan pendekatan data geologi regional, data seismik, data sumur, dan juga data pendukung lainnya. Pemodelan dan karakterisasi reservoar di lapangan Meranji pada formasi Namur meliputi distribusi fasies dan distribusi properti reservoar di formasi tersebut. Persebaran batupasir dan persebaran properti reservoar Namur secara lateral dipandu oleh atribut seismik dan impedansi akustik hasil inversi seismik. Hasil pemodelan menunjukkan bahwa unit batupasir yang paling tebal, morfologi chanel yang terpotong atau tidak menerus atau tidak berkembang ke sumur Cooba-1 dan Pelican-5, arah pengendapan chanel fasies batupasir dari timur laut menuju ke barat daya berkumpul ke sumur Meranji-1 dan persebaran lateral AI yang rendah membentuk suatu lensa yang menipis, kemungkinan tidak berkembang ke arah dua sumur lainnya, analisis ini mendukung hipotesa mengapa hanya pada sumur Meranji-1 mengalir hidrokarbon. ......On Meranji field there are three wells penetrated Namur Formation, but only Meranji-1 well that drain oil hydrocarbons from the Namur Formation. The needs of the regional geological informations as author references or limitations to map the distribution of facies in this field. As a basis for modeling properties of rocks, facies development needs to be known in detail by using a regional geological data, seismic data, well data, as well as other supporting data. Modeling and reservoir characterization in Meranji field in Namur formations include the distribution of facies and reservoir properties distribution in Namur formation. Distribution of sandstones facies and reservoir properties laterally guided by seismic attributes and seismic acoustic impedance inversion results. Modeling results indicate that the unit sandstone thickest, morphology channels are truncated or not continuous or does not develop into a well Cooba-1 and Pelican-5, direction of deposition of sandstone facies channel from the northeast toward southwest converge into well Meranji-1 and distribution of lower AI laterally forming a lens thinning, may not evolve towards two other wells, this analysis supports the hypothesis why only on Meranji-1 well flowed hydrocarbons.

Abstrak :
Prospek play reservoar dengan konsep sub thrust fault merupakan hal baru di cekungan Kutai. Cekungan Kutai merupakan cekungan sedimen tersier terluas dan terdalam di Indonesia. Cekungan ini masih memiliki banyak potensi reservoar hydrocarbon yang belum ditemukan dan harus terus dieksplorasi. Evaluasi prospek merupakan salah satu tahapan penting dalam eksplorasi hydrocarbon. Analisis sekat patahan dilakukan untuk menguji integritas jebakan pada prospek. Pemetaan geometri persebaran reservoar prospek menggunakan metode analisis spectral decomposisi. Tujuan tesis ini adalah untuk menyelidiki sebaran reservoar beserta keutuhan jebakan dengan menggunakan analisis Spektral Dekomposisi dan dengan menganalisis throw, transmsibility, dan juxtaposisi. Analisis patahan menentukan area leaking dan sealing pada bidang patahan. Dalam penelitian ini juga dilakukan analisis zona frekuensi rendah dimana anomali amplitudo diamati pada frekuensi rendah dan dibandingkan dengan amplitudo pada frekuensi pertengahan dan frekuensi tinggi. Analisis amplitude digunakan untuk membedakan kemungkinan lithologi dan fluida pengisinya. Anomali amplitudo terlihat pada frekuensi rendah dan menghilang pada frekuensi tinggi. Metode dekomposisi spektral yang digunakan adalah Continous Wavelet Transform (CWT) dengan menggunakan wavelet Morlet, Short Term Fourier Transform (STFT) dan Generelized Spectral Decomp (GSD). Hasil proses dekomposisi spektral pada frekuensi rendah (10 Hz) menunjukkan potensi area reservoar baru di kedalaman 1500-2500 ms. Hasil analisis sekat patahan juga memperlihatkan potensial jebakan di bawah sub thrust Patahan 2. Peta dari berbagai proses tersebut kemudian di-overlay untuk melihat peta resiko prospek eksplorasi di daerah penelitian.

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The prospect of a play reservoir with the concept of sub thrust fault is new in the Kutai basin. The Kutai Basin is the widest and deepest tertiary sedimentary basin in Indonesia. This basin still has many hydrocarbon reservoir potentials that have not yet been discovered and must be explored. Prospect evaluation is one of the important stages in hydrocarbon exploration. Analysis of fault seal is done to test the unity of the trap to the prospect. Geometry mapping of prospect reservoir distribution is defined by using spectral decomposition analysis method. The purpose of this thesis is to investigate the distribution of reservoirs and trap integrity by using Spectral Decomposition analysis and by analyzing the throw, transmissibility, and juxtaposition. Fault analysis determines the area of leaking and sealing in the fault plane. In this study also carried out low frequency zone analysis where amplitude anomalies is able to be observed at low frequencies and compared with amplitude at mid frequency and high frequency. Amplitude analysis is used to distinguish lithological possibilities and fill fluid. Amplitude anomalies are seen at low frequencies and disappear at high frequencies. The spectral decomposition method used is Continuous Wavelet Transform (CWT) using Morlet wavelets, Short Term Fourier Transform (STFT) and Generelized Spectral Decomp (GSD). The results of the spectral decomposition process at low frequencies (10 Hz) show the potential of the new reservoir area at a depth of 1500-2500 ms. The results of fault seal analysis also show potential trap under sub thrust Fault 2. Maps of the various processes are then overlaid to see the risk map of exploration prospects in the research area.

Abstrak :
Inversi seismik deterministik sudah banyak digunakan dalam lapangan eksplorasi dan pengembangan. Metode ini digunakan sebagai salah satu cara untuk karakterisasi reservoir dengan menghilangkan efek wavelet sehingga dapat membantu interpreter untuk memetakan struktur bawa permukaan dengan lebih baik. Akan tetapi, metode ini memiliki limitasi karena menggunakan impedansi rata-rata dari layer seismik dimana pada umumnmya nilai impendansi lebih kecil daripada impedansi data sumur sehingga dihasilkan model inversi yang tidak sesuai. Metode inversi stokastik menggunakan konsep geostatistikal, dimana variogram berperan penting dalam menghasilkan output yang sesuai. Pada inversi stokastik dihasilkan banyak realisasi inversi yang digunakan sebagai basis dalam analisis uncertainty, tiap realisasi akan sama pada tiap lokasi sumur yang digunakan namun akan berubah seiring dengan bertambahnya jarak spasial dari lokasi sumur. Metode inversi stokastik akan diaplikasikan pada lapangan gas “K” yang terletak di lepas pantai cekungan Bonaparte, Indoensia Timur. Data yang tersedia antara lain, sebagian dari 3D PSTM angle gather dengan luasan 1,300 km2, 3 sumur dengan data P-Sonic, S-Sonic, densitas, Gamma Ray, dan log resistivitas. Tambahan data berupa report komplesi dan report well testing tersedia untuk beberapa sumur. Lapangan gas “K” terletak pada undeformed continental margin Australia yang melampar kearah lndonesia, dimana secara geologi lapangan “K” terletak pada area Timur dari Sahul Platform dan memiliki struktur berupa tiltef fault block. Lapangan ini memiliki reservoir batupasir formasi Plover yang tersaturasi gas dengan hidrokarbon kolom cukup signifikan, dimana reservoir terdeposisi pada lingkungan shallow marine pada umur Middle Jurasic. Target utama pada lapangan gas “K” merupakan strukutural trap berupa horst block, tilted fault block yang berada dibawah sub-unconformity di umur Palaezoic. Penerapan metode inversi stokastik pada lapangan gas “K” menghasilkan kelebihan yang cukup signifikan dibandingkan dengan inversi deterministik. Reservoir pada lapangan gas “K” terdiri dari batupasir dengan persilangan shale tipis. Metode inversi stokastik dapat membedakan antara batupasir yang tersaturasi gas dengan intraformational shale tipis yang tidak teresolusi oleh seismik dan inversi deterministik. Hasil realisasi dapat digunakan untuk analisis uncertainty dengan probabilitas P10, P50, dan P90 dari facies yang dihasilkan. ......Deterministic seismik inversion method has been successfully used in various projects in exploration and development. This method enables the interpreter to get better understanding of subsurface by omitting the wavelet and tuning effects therefore quantitative reservoir properties can be generated. However, this method has significant limitation by generating average impedances of each layer, and the range of values is smaller than the impedance from the wells therefore the inversion will not produce results that are not within the calibration range. Stochastic seismik inversion is done by conditioning well data and reproducing spatially varying statistics using variogram which could overcome the deterministic limitation. This method generates multiple realizations of high-frequency elastic properties that are consistent with both seismik amplitude and well data. In such instances, stochastic seismik inversion method could provide the uncertainties associated with the models that have been generated. The proposed method is applied in “K” gas field which located in the offshore Bonaparte Basin, Eastern Indonesia. The available dataset for this work includes : part of PSTM 3D which cover 1,300 km2 in angle gather, and 3 wells with compressional sonic, shear sonic, density, gamma ray, and resistivity logs. Additional well completion and well testing reports are available for some wells. Geologically, the “K” field is located within relatively undeformed Australian continental margin that extends into Indonesian waters. It lies on the eastern extremity of the Sahul Platform and occupies a large tilted fault block bounded to the east and south by the Calder-Malita Grabens. This field contains a significant gas column, reservoired within shallow marine, highly mature, quartzose sandstone of the Middle Jurassic Plover Formation. Potential targets in the area may be large folds, horst blocks, tilted fault blocks ad sub-unconformity traps in the Palaeozoic section. The application of stochastic seismik inversion showed significant benefits compared to deterministic especially in “K” gas field where the reservoirs are stacked sandstone with intraformational shale. Some of the reservoir and all the intraformational shales are below seismik resolution. Stochastic seismic inversion able to distinguish those features, in addition the inverted volumes with multiple realizations with ranking criteria for P10, P50, and P90 of facies could be utilized to reduce the risk associated with exploration plan and field development.

Abstrak :
[ABSTRAK
Uranium merupakan salah satu bahan bakar PLTN. Eksplorasi uranium akan terus meningkat seiring dengan kebutuhan yang meningkat. Metode geomagnet, tahanan jenis dan polarisasi terinduksi dapat diterapkan dalam eksplorasi deposit uranium yang mineralisasinya berasosiasi dengan mineral sulfida. Pengolahan, analisis, dan interpretasi data geomagnet, tahanan jenis, dan polarisasi terinduksi dilakukan untuk dapat mengidentifikasi sebaran deposit uranium, litologi batuan, model geometri dalam 3 dimensi, serta memperkirakan sumber daya terunjuk di daerah Rabau Hulu, Kalan, Kalimantan Barat. Deposit uranium di daerah Rabau Hulu pada umumnya berasosiasi dengan sulfida, turmalin dan terdapat dalam batuan favourable. Gejala mineralisasi uranium dijumpai dalam bentuk-bentuk tidak teratur dan tidak merata terdiri atas mineral uraninit, pirit, kalkopirit, pirhotit, molibdenit, dan ilmenit. Pengolahan data menghasilkan nilai anomali medan magnet total, tahanan jenis, dan faktor logam yang selanjutnya dibuat penampang 2 dimensi. Penentuan nilai tahanan jenis dan polarisasi terinduksi dilakukan dengan mengkorelasi data sumur bor dengan hasil pengolahan data. Tahanan jenis pada zona deposit uranium bernilai kurang dari 2.000 Ωm dan nilai faktor logamnya lebih besar dari 90 mho/m. Zona deposit uranium ini semakin meluas seiring dengan kedalaman. Model 3 dimensi menunjukkan bahwa distribusinya berarah Barat Daya?Timur Laut dan berbentuk lensa. Kadar rata-rata uranium pada zona deposit di daerah Rabau Hulu adalah 0,0085 %. Massa jenis deposit uranium yang digunakan untuk menghitung sumber daya terunjuk adalah 2,83 gr/cm3.

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ABSTRACT Uranium is one of the nuclear fuel. Uranium exploration will continue to increase along with the increased of demand. Geomagnetic, resistivity and induced polarization methods can be applied in the uranium deposits exploration that mineralization is associated with sulphide minerals. Processing, analysis, and interpretation of geomagnetic, resistivity, and induced polarization data conducted in order to identify the distribution of uranium deposits, lithology, model geometry in 3 dimensions and indicated resource estimates in the area Rabau Hulu, Kalan, West Kalimantan. Uranium deposits in the area Rabau Hulu is generally associated with sulphides, tourmaline and contained in favorable rocks. Symptoms of uranium mineralization encountered in other forms of irregular and uneven consists minerals of uraninite, pyrite, chalcopyrite, pyrrhotite, molybdenite, and ilmenite. Data processing generates a magnetic field total anomalous values, resistivity, and metal factor which further created two-dimensional cross-section. Determination of resistivity and induced polarization conducted by boreholes to correlate the data with the results of data processing. Resistivity in the uranium deposits zone worth less than 2,000 Ωm and the value of metal factor greater than 90 mho/m. Uranium deposit zone is expanding along with the depth. Three dimensional modeling show that the distribution of deposits trending South West-North East and form lens. The average concentration of uranium in the deposit zone in the area Rabau Hulu is 0.0085%. The density of uranium deposits which are used to calculate the indicated resource is 2.83 g/cm3., Uranium is one of the nuclear fuel. Uranium exploration will continue to increase along with the increased of demand. Geomagnetic, resistivity and induced polarization methods can be applied in the uranium deposits exploration that mineralization is associated with sulphide minerals. Processing, analysis, and interpretation of geomagnetic, resistivity, and induced polarization data conducted in order to identify the distribution of uranium deposits, lithology, model geometry in 3 dimensions and indicated resource estimates in the area Rabau Hulu, Kalan, West Kalimantan. Uranium deposits in the area Rabau Hulu is generally associated with sulphides, tourmaline and contained in favorable rocks. Symptoms of uranium mineralization encountered in other forms of irregular and uneven consists minerals of uraninite, pyrite, chalcopyrite, pyrrhotite, molybdenite, and ilmenite. Data processing generates a magnetic field total anomalous values, resistivity, and metal factor which further created two-dimensional cross-section. Determination of resistivity and induced polarization conducted by boreholes to correlate the data with the results of data processing. Resistivity in the uranium deposits zone worth less than 2,000 Ωm and the value of metal factor greater than 90 mho/m. Uranium deposit zone is expanding along with the depth. Three dimensional modeling show that the distribution of deposits trending South West-North East and form lens. The average concentration of uranium in the deposit zone in the area Rabau Hulu is 0.0085%. The density of uranium deposits which are used to calculate the indicated resource is 2.83 g/cm3.]